TOHOKU UNIVERSITY Researchers

Takashi Watanabe

Section

Graduate School of Biomedical Engineering

Job title

Professor

Degree

博士（工学）（東北大学）
工学修士（東北大学）

researchmap

https://researchmap.jp/read0180276

J-GLOBAL ID

200901034107151060

Research History 3

2013/04 - Present

東北大学教授（医工学研究科）
2008/04 - 2013/03

東北大学准教授（医工学研究科）
2001/04 - 2008/03

東北大学助教授（情報シナジーセンター，工学研究科）

Education 2

Tohoku University　Graduate School, Division of Engineering　電気及通信工学

- 1991/03
Yamanashi University　Faculty of Engineering　電気工学科

- 1989/03

Committee Memberships 22

日本生体医工学会　代議員

2019/04 - Present
バイオメカニズム学会　理事

2018/04 - Present
バイオメカニズム学会　評議員

2006/04 - Present
電子情報通信学会　ソサイエティ論文誌編集委員会査読委員

2005/11 - Present
日本生体医工学会　ME技術教育委員会委員

2005/04 - Present
日本エム・イー学会　東北支部幹事

2003/01 - Present
電子情報通信学会ＭＥとバイオサイバネティックス研究専門委員会　委員長

2020/06 - 2021/06
電子情報通信学会ＭＥとバイオサイバネティックス研究専門委員会　副委員長

2019/06 - 2020/06
電子情報通信学会ＭＥとバイオサイバネティックス研究専門委員会　専門委員

2014/06 - 2019/06
電子情報通信学会ＭＥとバイオサイバネティックス研究専門委員会　幹事

2012/05 - 2014/06
日本生体医工学会　代議員

2005/04 - 2009
日本FES研究会　会計幹事

1994/04 - 2008/01
日本生体医工学会　第46回日本生体医工学会大会実行委員（会計担当）

2006/04 - 2007/05
バイオメカニズム学会・編集委員会　編集委員

2003/04 - 2007/04
International Functional Electrical Stimulation Society　11th Annual Conference of the International Functional Electrical Stimulation Society, Scientific Committee Co-Chair

2005/04 - 2006/10
計測自動制御学会　第5回制御部門大会実行委員

2004/10 - 2005/05
バイオメカニズム学会・編集委員会　編集委員会幹事

2003/04 - 2005/04
日本エム・イー学会　東北支部代表幹事

2000/01 - 2002/12
International Functional Electrical Stimulation Society　6th Annual Conference of the International Functional Electrical Stimulation Society組織委員

2000/12 - 2001/05
日本エム・イー学会　東北支部会計幹事

1999/01 - 1999/12
International Functional Electrical Stimulation Society　6th Annual Conference of the International Functional Electrical Stimulation Society実行委員

1998/07 - 1999/09
日本エム・イー学会　第38回日本生体医工学会大会実行委員（会計担当）

1998/04 - 1999/06

Show all ︎Show first 5

Professional Memberships 5

電子情報通信学会
バイオメカニズム学会
International Functional Electrical Stimulation Society
IEEE(The Institute of Electrical and Electronics Enginees,Inc.)
Japan Society for Medical and Biological Engineering

Research Interests 6

user interface
wearable sensor
evaluation of motor function
motion measurement
motion control
FES

Research Areas 2

Life sciences / Biomaterials / Medical Electronics and Biological Engineering
Life sciences / Biomedical engineering / Medical Electronics and Biological Engineering

Awards 4

生体医工学シンポジウムベストレビューワーアワード

2016/09/17　日本生体医工学会生体医工学シンポジウム編集委員会
石田實記念財団研究奨励賞

2013/11/08　石田實記念財団　無線型慣性センサによるウェアラブル下肢運動計測・解析システムのリハビリテーション応用に関する研究
生体医工学シンポジウムベストレビューワーアワード

2013/09/20　日本生体医工学会生体医工学シンポジウム編集委員会
平成12年度科学新聞賞・研究奨励賞・阪本研究刊行助成賞・阿部賞

2001/05/10　日本エム・イー学会　ダブルパルスによるM波を利用したFES制御時の筋疲労評価の検討

Papers 169

A Computer Simulation Test for Validation of Linear Model Predictive Control with Nonlinear Transformation for FES in Wrist Joint Control Peer-reviewed

Fauzan Arrofiqi, Takashi Watanabe, Achmad Arifin

2021 6th International Conference on Intelligent Informatics and Biomedical Sciences (ICIIBMS)　144-148　2021/11/25
Publisher: IEEE
DOI： 10.1109/iciibms52876.2021.9651660 　
A Feasibility Study of Gait Change Detection Using LSTM Based on Inertial Sensor Measurements under Fixed Step Widths Peer-reviewed

Kento Katayama, Takashi Watanabe

2021 6th International Conference on Intelligent Informatics and Biomedical Sciences (ICIIBMS)　111-115　2021/11/25
Publisher: IEEE
DOI： 10.1109/iciibms52876.2021.9651568 　
A Preliminary Study on Prediction of Initial Contact Timing During Gait Using LSTM for FES Control Peer-reviewed

Yuto Uwaseki, Takashi Watanabe

Converging Clinical and Engineering Research on Neurorehabilitation IV: Biosystems & Biorobotics　115-120　2021/10
Publisher: Springer International Publishing
DOI： 10.1007/978-3-030-70316-5_19 　

ISSN：2195-3562

eISSN：2195-3570
A Study on Reference Range of Healthy Subjects for Detection and Evaluation of Abnormal Foot Movement During Walking in Hemiplegic Subject Using Inertial Sensors Peer-reviewed

Taihei Noro, Takashi Watanabe, Katsunori Murakami, Naomi Kuge

Converging Clinical and Engineering Research on Neurorehabilitation IV: Biosystems & Biorobotics　109-113　2021/10
Publisher: Springer International Publishing
DOI： 10.1007/978-3-030-70316-5_18 　

ISSN：2195-3562

eISSN：2195-3570
Average Walking Speed Estimation with an Inertial Sensor in 10-m Walk Test: A Validation Test with Healthy Subjects Peer-reviewed

Takashi Watanabe

8th European Medical and Biological Engineering Conference　169-177　2021
Publisher: Springer International Publishing
DOI： 10.1007/978-3-030-64610-3_20 　

ISSN：1680-0737

eISSN：1433-9277
Design of Post-stroke Upper Limb Rehabilitation Game using Functional Electrical Stimulation for Hemiplegic Patient Peer-reviewed

Steven Seaver Wiarta, Achmad Arifin, Siti Halimah Baki, Fauzan Arrofiqi, Muhammad Hilman Fatoni, Takashi Watanabe

2020 International Conference on Computer Engineering, Network, and Intelligent Multimedia (CENIM)　2020/11/17
Publisher: IEEE
DOI： 10.1109/cenim51130.2020.9297963 　
Development of Artificial Neural Network Based Automatic Stride Length Estimation Method Using IMU: Validation Test with Healthy Subjects Peer-reviewed

Yoshitaka NOZAKI, Takashi WATANABE

IEICE Transactions on Information and Systems　E103.D　(9)　2027-2031　2020/09/01
Publisher: Institute of Electronics, Information and Communications Engineers (IEICE)
DOI： 10.1587/transinf.2019edl8227 　

ISSN：0916-8532

eISSN：1745-1361
Design of Myoelectric Control Command of Electric Wheelchair as Personal Mobility for Disabled Person Peer-reviewed

I Wayan Nudra Bajantika Pradivta, Achmad Arifin, Fauzan Arrofiqi, Takashi Watanabe

Proceedings of 2019 International Biomedical Instrumentation and Technology Conference　112-117　2019/10
A Design of Multipurpose Virtual Reality Game for Children with Autism Spectrum Disorder Peer-reviewed

Milla Rahmadiva, Achmad Arifin, Muhammad Hilman Fatoni, Siti Halimah Baki, Takashi Watanabe

Proceedings of 2019 International Biomedical Instrumentation and Technology Conference　1-6　2019/10
A Feasibility Test of Evaluation of Gait Movement by Using Center of Mass Estimation with Inertial Sensors Peer-reviewed

Yuho Takeda, Takashi Watanabe

IFMBE Proceedings　76　718-726　2019/09
A Study on Relationship between Walking Speed and Acceleration of Center of Mass Estimated with Inertial Sensors Peer-reviewed

Takashi Watanabe, Yuho Takeda

IFMBE Proceedings　76　694-702　2019/09
A Basic Study on Detection of Movement State in Stride by Artificial Neural Network for Estimating Stride Length of Hemiplegic Gait Using IMU

Yoshitaka Nozaki, Takashi Watanabe

2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)　2019/07
Publisher: IEEE
DOI： 10.1109/embc.2019.8856352 　
Research on Detection Method for Abnormal Gait UsingThree-dimensional Thigh Motion Analysis with Inertial Sensor Peer-reviewed

Maho SHIOTANI, Takashi WATANABE, Katsunori MURAKAMI, Naomi KUGE

57　(1)　1-7　2019/03
慣性センサを用いた大腿部ベクトル推定による片麻痺者歩行の3次元的運動異常の検出可能性 Peer-reviewed

塩谷真帆, 渡邉高志

バイオメカニズム学会誌　43　(1)　2019/02
A Feasibility Study on Thigh Inclination Angle Estimation With an Inertial Sensor Attched on the Shank Segment Peer-reviewed

Takashi Watanabe, Shinya Yasuhara

Proceedings of the 2018 IEEE Life Sciences Conference　2018/10
A Basic Test of Calibration Methods for Measurement of Three-dimensional Movements of Lower Limbs With Inertial Sensors Peer-reviewed

Takuma Ando, Takashi Watanabe

Proceedings of the 2018 IEEE Life Sciences Conference　211-214　2018/10
Experimental Tests of a Prototype of IMU-Based Closed-Loop Fuzzy Control System for Mobile FES Cycling with Pedaling Wheelchair

Takashi WATANABE, Takumi TADANO

IEICE Transactions on Information and Systems　E101.D　(7)　1906-1914　2018/07/01
Publisher: Institute of Electronics, Information and Communications Engineers (IEICE)
DOI： 10.1587/transinf.2017edp7299 　

ISSN：0916-8532

eISSN：1745-1361
A computer simulation test of feedback error learning-based FES controller for controlling random and cyclic movements Peer-reviewed

Takashi Watanabe, Naoya Akaike

IFMBE Proceedings　68/3　53-57　2018/05
Experimental evaluation of an assist chair for sit-to-stand on speed of flipping up a seat of chair Peer-reviewed

T. Suzuki, N. Tyler, A. Suda, H. Onishi, T. Muromaki, T. Watanabe

ICIIBMS 2017 - 2nd International Conference on Intelligent Informatics and Biomedical Sciences　2018-　239-242　2018/02/02
Publisher: Institute of Electrical and Electronics Engineers Inc.
DOI： 10.1109/ICIIBMS.2017.8279743 　

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Assist chairs with simple mechanism to flip up a seat at the front edge to assist sit-to-stand (STS) is well known as commercial products developed from around 1980. The speed of flipping up the seat on the assist chairs would play a key role how to adjust assisting STS in individual cases, but there is almost no discussion how the speed of flipping up the seat affects the benefit of assisting STS. The aim of study is to investigate the optimised speed of flipping up the seat of the assist chairs. As a first step, a motorised assist chair with controllable speed of flipping up the seat was developed and tested with four healthy participants in three seat height conditions High:520mm, Middle:420mm, and Low:320mm without and with flipping up the seat at maximum speed 30degree/second. Significant main effect of assisting was found on peak vGRF at Low seat height (p&lt 0.005) by Wilcoxon rank test. There was no significant effect at Middle (p=0.126) and High seat height (p=0.507). With assisting at the Low seat height, the reduction of peak vGRF means that the flipping up the seat successfully supports trunk movement and knee function to lift up the hip from the seat. All participants felt the assisting was effective to reduce the hardness of STS at the Low seat height. With further studies to optimise the speed of flipping the seat, the motorised assist chair in this study would provide a proper assist for individual STS movement, with leaving certain part of physical load for keeping muscle functioning.
A validation test of using shoulder joint moment in evaluation of load in wheelchair propulsion Peer-reviewed

D. Kobayashi, T. Watanabe, N. Tyler, T. Suzuki

2017 IEEE Life Sciences Conference, LSC 2017　2018-　242-245　2018/01/23
Publisher: Institute of Electrical and Electronics Engineers Inc.
DOI： 10.1109/LSC.2017.8268188 　

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Manual wheelchair is an effective device for assisting independent life of motor disabled subjects. However, many users of manual wheelchair have been suffered from shoulder pain because propelling the wheelchair needs repetitive movement of upper extremities. The purpose of this study was to examine a validity of using shoulder joint moment in evaluation of load on the users in wheelchair propulsion. Since shoulder joint moment can evaluate mechanical load on the shoulder, the indexes are expected to provide information to help wheelchair propulsion in decreasing of shoulder pain. Two evaluation indexes derived from shoulder joint moment were tested in this paper: Ft/Ms and Fr/Ms, which showed contribution of shoulder joint moment (MS) to wheelchair propulsion (tangential force on handrim FT) and to the resultant force on handrim (FR). These indexes were compared to the index FT/FR which was based on previous studies. Measurements of movements during wheelchair propulsion were performed with 3 healthy subjects on stationary wheelchair ergometer under the different conditions of propulsion speed and resistance of ergometer. Correlation coefficient between the proposed indexes and FT/FR were low (-0.51 to 0.10), which suggested that the proposed indexes had different information from the index FT/FR. Change of the index values between low and high propulsion load conditions were different between subjects. These results suggest that using indexes derived from shoulder joint moment would be effective in evaluation of load in wheelchair propulsion.
An Examination of Stimulation Timing Patterns for Mobile FES Cycling under Closed-loop Control of Low Cycling Speed Peer-reviewed

Takashi Watanabe, Taukmi Tadano

Converging Clinical and Engineering Research on Neurorehabilitation III　21　1106-1110　2018
A Pilot Study of Relationship between Hip Joint Movement and FES Foot Drop Correction with a Hemiplegic Subject Peer-reviewed

Kei Kikuchi, Takashi Watanabe, Ryusei Morita, Katsunori Murakami, Naomi Kuge

Converging Clinical and Engineering Research on Neurorehabilitation III　21　243-247　2018
Design of Closed-Loop Fuzzy FES Controller and Tests in Controlling Knee Extension Movements Peer-reviewed

Takashi Watanabe, Takumi Tadano

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E100D　(9)　2261-2264　2017/09
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1587/transinf.2017EDL8061 　

ISSN：1745-1361

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Fuzzy controller can be useful to realize a practical closed-loop FES controller, because it is possible to make it easy to design FES controller and to determine its parameter values, especially for controlling multi-joint movements by stimulating many muscles including antagonistic muscle pairs. This study focused on using fuzzy controller for the closed-loop control of cycling speed during FES cycling with pedaling wheelchair. However, a designed fuzzy controller has to be tested experimentally in control performance. In this paper, a closed-loop fuzzy FES controller was designed and tested in knee extension movements comparing to a PID controller with healthy subjects before applying to FES cycling. The developed fuzzy controller showed good control performance as a whole in comparing to PID controller and its parameter values were determined through simple control tests of the target movement.
A basic study on improvement of gait of a hemiplegic subject by a body weight supported lift and FES foot drop correction

Morita Ryusei, Kikuchi Kei, Watanabe Takashi, Murakami Katsunori, Kuge Naomi

Transactions of Japanese Society for Medical and Biological Engineering　55　(3)　144-144　2017
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.55Annual.144 　

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Hemiplegic subjects often show abnormal gait such as a circumduction gait. It is difficult for the subjects to acquire practical walking ability because of the abnormal gait. A body weight supported (BWS) training has been used clinically to improve the symmetry of gait pattern. The purpose of this study was to evaluate a variation in the symmetry of gait pattern by applying a BWS lift to hemiplegic patients by using inertial sensors. In this report, gait with the BWS lift and foot drop correction by FES was measured with a hemiplegic subject. The BWS lift with FES foot drop correction improved the limping gait and the symmetry of the gait pattern, while limping gait was not improved only by the BWS lift.
A Preliminary Test of a Portable Prototype System of FES Foot Drop Correction and Gait Measurements with a Hemiplegic Subject Peer-reviewed

Takashi Watanabe, Shun Endo, Ryusei Morita, Katsunori Murakami, Naomi Kuge

CONVERGING CLINICAL AND ENGINEERING RESEARCH ON NEUROREHABILITATION II, VOLS 1 AND 2　15　1217-1221　2017
Publisher: SPRINGER INTERNATIONAL PUBLISHING AG
DOI： 10.1007/978-3-319-46669-9_198 　

ISSN：2195-3562

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In this study, a portable prototype system of FES foot drop correction and gait measurements was tested with a hemiplegic subject to develop FES rehabilitation system for gait of hemiplegic subjects. The prototype system consisted of a tablet-type device and 2 inertial sensors and an electrical stimulator. The system worked properly during walking with FES foot drop correction and foot inclination angles, stride time and gait event timings were obtained. Measurement of gait information during rehabilitation training can be useful to evaluate the training effect.
Determination of stimulation timing pattern based on EMG signals for fes cycling with pedaling wheelchair Peer-reviewed

Takashi Watanabe, Takumi Tadano

IFMBE Proceedings　65　394-397　2017
Publisher: Springer Verlag
DOI： 10.1007/978-981-10-5122-7_99 　

ISSN：1680-0737

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A simple functional electrical stimulation (FES) cycling control with the pedaling wheelchair was developed in our previous study. However, it needed measurement of muscle response time of each stimulated muscle before cycling. In addition, cycling speed varied between subjects and between trials. In this study, stimulation timing pattern was determined based on EMG signals and tested in FES cycling for the pedaling wheelchair with healthy subjects. The EMG-based stimulation timing, in which stimulation start timing for the rectus femoris was modified to be the same as the vastus lateralis, was shown to be effective improving cycling speed and stability of FES cycling. The timing pattern could be practical because it does not require measurements of muscle response times.
Examination of Inertial Sensor-Based Estimation Methods of Lower Limb Joint Moments and Ground Reaction Force: Results for Squat and Sit-to-Stand Movements in the Sagittal Plane Peer-reviewed

Jun Kodama, Takashi Watanabe

SENSORS　16　(8)　2016/08
Publisher: MDPI AG
DOI： 10.3390/s16081209 　

ISSN：1424-8220

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Joint moment estimation by a camera-based motion measurement system and a force plate has a limitation of measurement environment and is costly. The purpose of this paper is to evaluate quantitatively inertial sensor-based joint moment estimation methods with five-link, four-link and three-link rigid body models using different trunk segmented models. Joint moments, ground reaction forces (GRF) and center of pressure (CoP) were estimated for squat and sit-to-stand movements in the sagittal plane measured with six healthy subjects. The five-link model and the four-link model that the trunk was divided at the highest point of the iliac crest (four-link-IC model) were appropriate for joint moment estimation with inertial sensors, which showed average RMS values of about 0.1 Nm/kg for all lower limb joints and average correlation coefficients of about 0.98 for hip and knee joints and about 0.80 for ankle joint. Average root mean square (RMS) errors of horizontal and vertical GRFs and CoP were about 10 N, 15 N and 2 cm, respectively. Inertial sensor-based method was suggested to be an option for estimating joint moments of the trunk segments. Inertial sensors were also shown to be useful for the bottom-up estimation method using measured GRFs, in which average RMS values and average correlation coefficients were about 0.06 Nm/kg and larger than about 0.98 for all joints.
Comparison of Muscle Stimulation Groups for Simplified Practical FES Cycling Control with Cycling Wheelchair: An Experimental Test with Healthy Subjects Peer-reviewed

Takashi Watanabe, Yuta Karasawa

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E99D　(5)　1345-1352　2016/05
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1587/transinf.2015EDP7135 　

ISSN：1745-1361

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The cycling wheelchair "Profhand" was developed in Japan as locomotion and lower limb rehabilitation device for hemiplegic subjects and elderly persons. Functional electrical stimulation (FES) control of paralyzed lower limbs enables application of the Profhand to paraplegic subjects as a rehabilitation device. In this paper, simplified muscle stimulation control for FES cycling with Profhand was examined for practical application, because cycling speed was low and not stable in our preliminary study and there was a difficulty in setting stimulation electrodes for the gluteus maximus. First, a guideline of target cycling speed to be achieved by FES cycling was determined from voluntary cycling with healthy subjects in order to evaluate FES cycling control. The cycling speed of 0.6m/s was determined as acceptable value and 1.0m/s was as ideal one. Then, stimulation to the gluteus maximus and that to the dorsiflexor muscles in addition to the quadriceps femoris were examined for simple FES cycling control for Profhand with healthy subjects. Stimulation timing was adjusted automatically during cycling based on muscle response time to electrical stimulation and cycling speed, which was shown to be effective for FES cycling control. Simple FES cycling control with Profhand removing stimulation to the gluteus maximus was found to be feasible. Stimulation to the dorsiflexor muscles with the quadriceps femoris was suggested to be effective for practical, simple FES cycling with Profhand in case of removing the gluteus maximus stimulation.
Potential of M-wave Elicited by Double Pulse for Muscle Fatigue Evaluation in Intermittent Muscle Activation by Functional Electrical Stimulation (FES) for Motor Rehabilitation Peer-reviewed

Naoto Miura, Takashi Watanabe

Journal of Medical Engineering　2016　2016/02/28

DOI： 10.1155/2016/6957287 　
Feasibility Study of Inertial Sensor-based Joint Moment Estimation Method during Human Movements A Test of Multi-Link Modeling of the Trunk Segment Peer-reviewed

Takashi Watanabe, Jun Kodama

Proceedingd of the 9th International Conference on Bio-inspired Systems and Signal Processing　248-255　2016/02/05
A study of coordination system alignment method for measurement accuracy evaluation using inertial sensor

Shiotani Maho, Watanabe Takashi

Transactions of Japanese Society for Medical and Biological Engineering　54　(27)　S182-S182　2016
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.54Annual.S182 　

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In these days, inertial sensors are used to measure body movements, for example joint angles or segment inclination angles. In many reports that refer to angle measurement, results from sensor systems were compared to those from optical motion analysis system to evaluate measurement accuracy. However, the global coordinate systems doesn't match exactly between sensor and motion analysis systems, which cause problem in the accuracy evaluation. In this paper, a method to define standardized coordination system for several measurement systems was developed. At first, two postures were measured with sensor and motion analysis system, and from these measurement data, the standardized coordinate system was defined. Then, difference between the coordination system of sensor system or motion analysis system and the standardized coordination system was calculated. The data measured from each system were recalculated in the standardized coordination, respectively. Therefore, angle measurement accuracy of sensor system was evaluated more precisely.
A Basic Study on Temporal Parameter Estimation of Wheelchair Propulsion based on Measurement of Upper Limb Movements Using Inertial Sensors Peer-reviewed

Takashi Watanabe, Kodai Miyazaki, Maho Shiotani, Andrew Symonds, Catherine Holloway, Tatsuto Suzuki

2016 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS (SMC)　2729-2733　2016
Publisher: IEEE
DOI： 10.1109/SMC.2016.7844652 　

ISSN：1062-922X

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Wheelchairs are the most widely used assistive device to aid activities of daily living (ADL) for disabled people. However, manual pushing of a wheelchair frequently leads to overuse of upper extremities causing shoulder pain and carpal tunnel syndrome. The purpose of this study was to test a novel method of estimating temporal parameters of wheelchair propulsion using inertial sensors. In this paper, normalized coordinate values of the vector defined on the upper arm were calculated from an inertial sensor attached on the upper arm. The number of strokes and push cycle timings including duration of propulsion and recovery phases were estimated for steady state wheelchair propulsion. This estimation was completed using a novel vector-based approach and a previously published resultant acceleration method; both were compared to timings measured using the SmartWheel. Measurements were performed on level and sloped surfaces with 10 able bodied subjects. The vector-based method improved estimation of the number of strokes when compared to the resultant acceleration method. However, the push cycle was estimated with better accuracy by the resultant acceleration method. Therefore, a combination of the vector-based and the resultant acceleration methods is proposed to ensure more accurate estimation of temporal parameters. The results suggest inertial sensors can be used to measure wheelchair activity accurately and reliably.
Development of a prototype of portable FES rehabilitation system for relearning of gait for hemiplegic subjects Peer-reviewed

Takashi Watanabe, Shun Endo, Ryusei Morita

Healthcare Technology Letters　3　(4)　284-289　2016
Publisher: Institution of Engineering and Technology
DOI： 10.1049/htl.2016.0045 　

ISSN：2053-3713

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This study aimed at developing a prototype of portable FES rehabilitation system for relearning gait pattern of healthy subjects, which can measure gait information during walking applying electrical stimulation for foot drop correction or providing timing information. A gait event detection method using an inertial sensor attached on the foot was determined based on gait of healthy subjects from simultaneous measurements with pressure sensors. From the result of comparing the detected gait event timings with EMG signal of the tibialis anterior muscle during walking of healthy subjects, the toe off and the foot flat timings detected by the inertial sensor were suggested to be useful to determine the stimulation timing for the foot drop correction. The gait event detection method was implemented in a prototype of portable FES rehabilitation system consisting of an 8-inch tablet-type device, 2 inertial sensors and an electrical stimulator. The portable system was examined with hemiplegic subjects under the conditions of FES foot drop correction and inducing voluntary effort to develop ankle dorsiflexion at the timing given by electrical stimulation with small stimulation intensity. The system was considered to be useful for gait rehabilitation of hemiplegia using FES foot drop correction or inducing voluntary effort.
A Basic Study on Walking Speed Estimaiton Using Inertial Sensors for Gait Rehabilitation

Tasuku Miyazawa, Takashi Watanabe

Proceedings of the 12th International Conference on Ubiquitous Healthcare (u-Healthcare2015)　92　2015/11/30
Measurement of EMG Signals for Determination of Stimulation Timing Pattern for FES Cycling with Cycling Wheelchair

Takumi Tadano, Takashi Watanabe

Proceedings of the 12th International Conference on Ubiquitous Healthcare (u-Healthcare2015)　20　2015/11/30
A Validation Test of a Simple Method of Stride Length Measurement Only with Inertial Sensors and a Preliminary Test in FES-assisted Hemiplegic Gait Peer-reviewed

T. Watanabe, T. Miyazawa

WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING, 2015, VOLS 1 AND 2　51　1111-1114　2015
Publisher: SPRINGER INT PUBLISHING AG
DOI： 10.1007/978-3-319-19387-8_270 　

ISSN：1680-0737

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The purpose of this study was to test stride length measurement only with inertial sensors to for the simple gait evaluation system developed in our previous study to support rehabilitation, healthcare and so on. In this paper, a calculation method of the stride length was developed, in which acceleration and angular velocity signals of the foot were used. The integration period of the acceleration for calculation of each stride length was automatically detected by the acceleration signal. First, the measurement method was evaluated in 10 m walking of 6 neurologically intact subjects. The average values of error and absolute error of measured stride lengths were 0.38 +/- 4.77% and 3.36 +/- 3.04%, respectively. Correlation coefficient of the measured length with the reference data was 0.910 and the slope of the regression equation was 0.978. Then, stride lengths of a hemiplegic subject were measured in 10 m walking with and without FES-assisted foot drop correction. Although there was no difference in stride length between with and without the FES-assist, the calculated data from inertial sensor signals supported that the time for 10 m walking measured by therapists decreased when the subject walked with the FES-assist. It was expected that the stride length measurement only with inertial sensor would be practical, and it can be implemented easily.
A Basic Study on Quantitative Evaluation of 3-dimensional Foot Contact with an Inertial Sensor for FES Foot Drop Correction Peer-reviewed

Maho Shiotani, Takashi Watanabe

2015 37TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)　6684-6687　2015
Publisher: IEEE
DOI： 10.1109/EMBC.2015.7319926 　

ISSN：1557-170X

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In these days, FES is used to control ankle dorsiflexion of hemiplegic gait. Since not only dorsiflexion but also 3-dimensional foot contact isimportant for gait stability in hemiplegic gait, evaluation and control system of 3-dimensional foot contact with FES is needed to correct foot movement. In this study, the timing of initial contact and the timing when foot movement became stationary in the sagittal plane were detected, and the inclination angles in the sagittal and the frontal planes at these timings were used for evaluation. Using the inclination angles, 10 m walking of a hemiplegic subject under the 4 different gait conditions were quantitatively evaluated. The gait conditions were without FES, stimulation to the tibialis anterior, stimulation to the common peroneal nerve, and stimulation to both the tibialis anterior and the common peroneal nerve. Result of evaluation with the inclination angles showed that stimulation to the tibialis anterior could control foot contact appropriately in the sagittal plane, and stimulation to the common peroneal nerve was better to control foot inclination angle in the frontal plane. Inclination angle at the beginning of the stance phase indicated that FES system which used in clinical site commonly is not appropriate to control 3-dimensional foot contact. It was shown that inclination angle at the beginning of the stance phase was useful to evaluate 3-dimensional foot movements for FES foot drop correction.
Comparison of Angle Measurements Between Integral-Based and Quaternion-Based Methods Using Inertial Sensors for Gait Evaluation Peer-reviewed

Takashi Watanabe, Yuta Teruyama, Kento Ohashi

BIOMEDICAL ENGINEERING SYSTEMS AND TECHNOLOGIES, BIOSTEC 2014　511　274-288　2015
Publisher: SPRINGER-VERLAG BERLIN
DOI： 10.1007/978-3-319-26129-4_18 　

ISSN：1865-0929

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The measurement method of lower limb angles, which were based on the integral of angular velocity with Kalman filter, was validated previously in measurement of angles in a plane with a rigid body model of double pendulum and shown to be practical in measurement of angles in the sagittal plane during gait of healthy subjects. In this paper, in order to realize practical measurements of 3 dimensional (3D) movements with inertial sensors, the previously developed integral-based angle calculation method with variable Kalman gain and a quaternion-based one with fixed gain were tested. First, the quaternion-based method showed higher measurement accuracies for angles in the sagittal and the frontal planes during 3D movements of a rigid body model of lower limb than that of the integral-based one. Second, the integral-based method was shown to be effective in measurement of angles in the sagittal plane of healthy subjects during treadmill walking compared to the quaternion-based one, which suggested effectiveness of the variable Kalman gain method. Third, the integral-based method was shown to cause inappropriate results in some cases of calculation of lower limb angles of hemiplegic subjects during gait, while some of such cases could be measured appropriately with the quaternion-based one. The results of this paper suggested that the quaternion-based method would be more effective with a variable Kalman-gain for measurement of 3D movements. The integral-based method was also suggested to be useful for measurement of angles in the sagittal plane of healthy subjects during gait.
病気別にみた脳卒中片麻痺者の歩行改善に向けて -生活期から-

芝崎淳, 阿部浩明, 渡邉高志

理学療法学　41　(8)　567-572　2014/12/20
Publisher: Japanese Society of Physical Therapy
DOI： 10.15063/rigaku.KJ00009647380 　
An Effectiveness of M-waves Elicited by Additional Pulses in Muscle Fatigue Evaluation for Repetitive Training with FES in Motor Rehabilitation Peer-reviewed

Watanabe T, Miura N

Proceedings the XX Congress of the International Society of Electrophysiology and Kinesiology (ISEK)　2014/07
Angle Measurements During 2D and 3D Movements of a Rigid Body Model of Lower Limb: Comparison between Integral-based and Quaternion-based Methods Peer-reviewed

Takashi Watanabe, Kento Ohashi

Proceedings. 7th International Conference on Bio-inspired Systems and Signal Processing (BIOSIGNALS 2014)　35-44　2014/03

DOI： 10.5220/0004793600350044 　
Measurement of gait movements of a hemiplegic subject with wireless inertial sensor system before and after robotic-assisted gait training in a day Peer-reviewed

Takashi Watanabe, Jun Shibasaki

IFMBE Proceedings　41　1730-1733　2014
Publisher: Springer Verlag
DOI： 10.1007/978-3-319-00846-2_427 　

ISSN：1680-0737

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This study aimed to test a possibility of using wireless inertial sensor system in evaluation of gait rehabilitation clinically. Gait movements of a hemiplegic subject were measured with the sensor system during 10 m walking before and after robotic-assisted gait training in a day. Segment inclination angles and joint angles of the lower limbs were calculated from measured angular velocities and acceleration signals based on Kalman filter. Gait event timings were also detected by foot angular velocities and shank acceleration signals. The measured data showed that gait movement changed after the training, which were considered to be improvements by the instruction of the therapist. The robotic-system could be effective for the training based on the instruction. The wireless inertial sensor system would be useful for measurement and evaluation of movements in rehabilitation clinically. © Springer International Publishing Switzerland 2014.
A Basic Study on a Method of Evaluating 3-dimentional Foot Movements in Walking Peer-reviewed

Maho Shiotani, Takashi Watanabe

2014 IEEE-EMBS INTERNATIONAL CONFERENCE ON BIOMEDICAL AND HEALTH INFORMATICS (BHI)　543-546　2014
Publisher: IEEE
DOI： 10.1109/BHI.2014.6864422 　

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Lower limb motor function is important for activities of daily living. Since gait movements of elderly subjects differ from those of young people, gait measurement is considered to be effective for evaluating lower limb motor function. In this paper, focusing on foot movements during gait, a method of evaluating 3-dimentional movements of the foot during walking was examined. Gait movements were measured with 3 healthy females using the wireless inertial sensor system developed by our research group. Then, foot inclination angle and vector locus of the foot vector were calculated from angular velocity and acceleration signals by using quaternion-based attitude representation. They were projected onto each plane of the global coordinate system. The results showed similar angle waveforms and locus patterns between subjects. These suggested that the angles and the vector loci would be useful in evaluation of lower limb motor function. Developing quantitative evaluation method and making clear meanings of the angles and the vector loci projected to the planes are necessary.
A Preliminary Study on Evaluation of Circumduction Movement during Gait with Wireless Inertial Sensors Peer-reviewed

Maho Shiotani, Takashi Watanabe

2014 36TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)　5828-5831　2014
Publisher: IEEE
DOI： 10.1109/EMBC.2014.6944953 　

ISSN：1557-170X

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Recently, inertial sensors have been used to measure human movements for the purpose of rehabilitation. In evaluation of motor function for rehabilitation, reference data measured from healthy subjects with inertial sensors is needed. In addition, since lower limbs perform 3-dimensional movements during gait, it is needed to analyze 3-dimensional gait movements. The plot of 3-dimensional vector locus can be useful to understand 3-dimensional movements. The purposes of this paper were to show usefulness of the vector locus in understanding circumduction during gait, and to test an evaluation parameter for 3-dimensional movements during walking as reference data. Gait of 12 healthy subjects were measured, and then vector loci were plotted in the 3-dimensional space. Shape of the vector locus was evaluated by the width of each component as one of the reference data. It was suggested that the vector loci plotted in 3-dimensioinal space or those projected on horizontal plane were useful to understand circumduction during gait. It was also suggested that the width of vector locus was useful to evaluate differences of movement between subjects.
A Test of Controlling Different Muscles in FES Cycling with Cycling Wheelchair "Profhand" Peer-reviewed

Takashi Watanabe, Yuta Karasawa, Yasunobu Handa

2014 IEEE 19TH INTERNATIONAL FUNCTIONAL ELECTRICAL STIMULATION SOCIETY ANNUAL CONFERENCE (IFESS)　2014
Publisher: IEEE
DOI： 10.1109/IFESS.2014.7036742 　

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The cycling wheelchair "Profhand" developed by our research group in Japan has been found to be useful in rehabilitation of motor function of lower limbs. The cycling wheelchair can also be applied to rehabilitation of paraplegic subjects by controlling lower limbs with FES. In this paper, FES control without stimulation to the gluteus maximus and that with stimulation to the tibialis anterior were tested for FES cycling with Profhand with healthy subjects, because cycling speed was low and not stable in our previous study and there was a difficulty in setting stimulation electrodes to the gluteus maximus. Stimulation to the quadriceps femoris, the gluteus maximus and the tibialis anterior showed the highest cycling speed. FES control without stimulation to the gluteus maximus was also possible to propel Profhand. Since effective muscle was different between individuals, it is preferable to select muscle group based on the patient's condition. Although stimulation to the tibialis anterior could be useful, it is necessary to study appropriate stimulation timing of each muscle.
A Preliminary Study on Analyzing 3-Dimentional Foot Movements in 10 m Walking with FES-Assisted Foot Drop Correction Peer-reviewed

Maho Shiotani, Takashi Watanabe

ABSTRACT BOOK, 35th Annual Conference of the IEEE EMBS　51　U-26-U-26　2013/07/03
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.51.U-26 　

ISSN：1347-443X
A Feasibility Study of FES Cycling with Cycling Wheelchair “Profhand” Peer-reviewed

Takashi Watanabe, Takuya Murakami, Yasunobu Handa

Proceedings of the 18th Annual Conference of the International FES Society　159-162　2013/06/06
Preliminary Tests of a Prototype FES Control System for Cycling Wheelchair Rehabilitation Peer-reviewed

Takashi Watanabe, Takuya Murakami, Yasunobu Handa

2013 IEEE 13TH INTERNATIONAL CONFERENCE ON REHABILITATION ROBOTICS (ICORR)　2013
Publisher: IEEE
DOI： 10.1109/ICORR.2013.6650484 　

ISSN：1945-7898

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The cycling wheelchair "Profhand" developed by our research group in Japan has been found to be useful in rehabilitation of motor function of lower limbs. It is also expected for rehabilitation of paraplegic subjects to propel the cycling wheelchair by lower limbs controlled by functional electrical stimulation (FES). In this paper, a prototype FES control system for the cycling wheelchair was developed using wireless surface stimulators and wireless inertial sensors and tested with healthy subjects. The stimulation pattern that stimulated the quadriceps femoris and the gluteus maximus at the same time was shown to be effective to propel the Profhand. From the analysis of steady state cycling, it was shown that the cycling speed was smaller and the variation of the speed was larger in FES cycling than those of voluntary cycling. Measured angular velocity of the crank suggested that stimulation timing have to be changed considering delay in muscle response to electrical stimulation and cycling speed in order to improve FES cycling. It was also suggested that angle of the pedal have to be adjusted by controlling ankle joint angle with FES in order to apply force appropriately.
A Basic Study on Variable-Gain Kalman Filter based on Angle Error Calculated from Acceleration Signals for Lower Limb Angle Measurement with Inertial Sensors Peer-reviewed

Yuta Teruyama, Takashi Watanabe

2013 35TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)　3427-3430　2013
Publisher: IEEE
DOI： 10.1109/EMBC.2013.6610277 　

ISSN：1557-170X

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In this study, development of wearable motion measurement system using inertial sensors has been focused with the aim of rehabilitation support. For measurement of lower limb joint angles with inertial sensors, Kalman-filtering-based angle measurement method was developed. However, it was required to reduce variation of measurement errors that depended on movement speeds or subjects. In this report, variable-gain Kalman filter based on the difference between the estimated angle by the Kalman filter and the angle calculated from acceleration signals was tested. From angle measurement during treadmill walking with healthy subjects, it was shown that measurement accuracy of the foot inclination angle was significantly improved with the proposed method compared to the method of fixed parameter value.
A Trial of Making Reference Gait Data for Simple Gait Evaluation System with Wireless Inertial Sensors Peer-reviewed

Yuta Karasawa, Yuta Teruyama, Takashi Watanabe

2013 35TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)　3431-3434　2013
Publisher: IEEE
DOI： 10.1109/EMBC.2013.6610278 　

ISSN：1557-170X

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Recently, the use of wearable inertial sensors have been widely studied in the field of human movement analysis. Our research group developed a wearable motion measurement system using the wireless inertial sensors for rehabilitation training and daily exercise. However, there are few reference data to evaluate motor function. In this paper, reference data of joint and inclination angles of lower limb and that of gait event timing for gait evaluation were made by measurement with 4 healthy subjects in their twenties. Average values of inclination and joint angles and gait event timings were similar to those seen in literature. These suggest that the averaged data obtained in this paper can be used as reference data. Then, gait data of a healthy subject in his thirties were compared with the reference data. Most of angles and all the gait event timings were considered to be standard of 20's. However, some angles of the healthy subject in his thirties were considered not to be the standard partly. These differences in evaluation were considered to depend on a level of similarity of movement to the reference data. It was expected to evaluate the level of similarity of movement from various parameters.
Experimental evaluation of balance prediction models for sit-to-stand movement in the sagittal plane Peer-reviewed

Oscar David Pena Cabra, Takashi Watanabe

Computational and Mathematical Methods in Medicine　2013　2013

DOI： 10.1155/2013/592328 　

ISSN：1748-670X 1748-6718

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Evaluation of balance control ability would become important in the rehabilitation training. In this paper, in order to make clear usefulness and limitation of a traditional simple inverted pendulum model in balance prediction in sit-to-stand movements, the traditional simple model was compared to an inertia (rotational radius) variable inverted pendulum model including multiple-joint influence in the balance predictions. The predictions were tested upon experimentation with six healthy subjects. The evaluation showed that the multiple-joint influence model is more accurate in predicting balance under demanding sit-to-stand conditions. On the other hand, the evaluation also showed that the traditionally used simple inverted pendulum model is still reliable in predicting balance during sit-to-stand movement under non-demanding (normal) condition. Especially, the simple model was shown to be effective for sit-to-stand movements with low center of mass velocity at the seat-off. Moreover, almost all trajectories under the normal condition seemed to follow the same control strategy, in which the subjects used extra energy than the minimum one necessary for standing up. This suggests that the safety considerations come first than the energy efficiency considerations during a sit to stand, since the most energy efficient trajectory is close to the backward fall boundary. © 2013 Oscar David Pena Cabra and Takashi Watanabe.
Movement Change Induced by Voluntary Effort with Low Stimulation Intensity FES-assisted Dorsiflexion: A Case Study with a Hemiplegic Subject Peer-reviewed

Takashi Watanabe, Shun Endo, Katsunori Murakami, Yoshimi Kumagai, Naomi Kuge

2013 6TH INTERNATIONAL IEEE/EMBS CONFERENCE ON NEURAL ENGINEERING (NER)　327-330　2013
Publisher: IEEE
DOI： 10.1109/NER.2013.6695938 　

ISSN：1948-3546

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This study focused on functional electrical stimulation (FES) to assist production of voluntary movement for gait rehabilitation of hemiplegic subjects. Movements during walking under the low stimulation intensity FES with voluntary effort of dorsiflexion (vL-FES) condition were compared with those under conditions of no stimulation, low intensity FES only and FES. Electrical stimulation was applied to assist ankle dorsiflexion in the swing phase. Gait movements were measured with wireless inertial sensors. It was shown that the vL-FES condition produced partly similar angle pattern with FES condition. It was also suggested from shortened stride time and increased inclination angle range of the thigh that walking speed increased under the vL-FES and FES walking conditions. However, electrical stimulation started at the heel off decreased plantar flexion of the foot at around the toe off. It was considered that the vL-FES condition could be useful as a method of rehabilitation using FES, and that plantar flexion control by FES or modifying the timing of applying electrical stimulation for ankle dorsiflexion had to be studied.
Effectiveness of variable-gain kalman filter based on angle error calculated from acceleration signals in lower limb angle measurement with inertial sensors Peer-reviewed

Yuta Teruyama, Takashi Watanabe

Computational and Mathematical Methods in Medicine　2013　2013
Publisher: Hindawi Publishing Corporation
DOI： 10.1155/2013/398042 　

ISSN：1748-6718 1748-670X

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The wearable sensor system developed by our group, which measured lower limb angles using Kalman-filtering-based method, was suggested to be useful in evaluation of gait function for rehabilitation support. However, it was expected to reduce variations of measurement errors. In this paper, a variable-Kalman-gain method based on angle error that was calculated from acceleration signals was proposed to improve measurement accuracy. The proposed method was tested comparing to fixed-gain Kalman filter and a variable-Kalman-gain method that was based on acceleration magnitude used in previous studies. First, in angle measurement in treadmill walking, the proposed method measured lower limb angles with the highest measurement accuracy and improved significantly foot inclination angle measurement, while it improved slightly shank and thigh inclination angles. The variable-gain method based on acceleration magnitude was not effective for our Kalman filter system. Then, in angle measurement of a rigid body model, it was shown that the proposed method had measurement accuracy similar to or higher than results seen in other studies that used markers of camera-based motion measurement system fixing on a rigid plate together with a sensor or on the sensor directly. The proposed method was found to be effective in angle measurement with inertial sensors. © 2013 Yuta Teruyama and Takashi Watanabe.
A Case Study of Angle Measurements in Foot Drop Correction by FES under Different Stimulation Conditions Peer-reviewed

Watanabe T, Endo S, Miura N, Murakami K, Kumagai Y, Kuge N

Proceedings of the 17th Annual Conference of the International FES Society　303-306　2012/09
A Preliminary Test of Lower Limb Joint Moment Estimation Method without Ground Reaction Force using Inertial Sensors Peer-reviewed

Takashi Watanabe, Hiroaki Mori, Tatstuto Suzuki

ABSTRACT BOOK, 34th Annual Conference of the IEEE EMBS　661　2012/08
A TEST OF MULTICHANNEL CLOSED-LOOP FES CONTROLLER IN WRIST JOINT MOVEMENTS OF A HEMIPLEGIC SUBJECT

Takashi Watanabe

SAITO HO-ON KAI NATURAL HISTORY RESEARCH BULLETIN　(76)　79-87　2012/03
Kalman-Filtering-Based Joint Angle Measurement with Wireless Wearable Sensor System for Simplified Gait Analysis Peer-reviewed

Hiroki Saito, Takashi Watanabe

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E94D　(8)　1716-1720　2011/08
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1587/transinf.E94.D.1716 　

ISSN：0916-8532

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The aim of this study is to realize a simplified gait analysis system using wearable sensors. In this paper, a joint angle measurement method using Kalman filter to correct gyroscope signals from accelerometer signals was examined in measurement of hip, knee and ankle joint angles with a wireless wearable sensor system, in which the sensors were attached on the body without exact positioning. The lower limb joint angles of three healthy subjects were measured during gait with the developed sensor system and a 3D motion measurement system in order to evaluate the measurement accuracy. Then, 10 m walking measurement was performed under different walking speeds with a healthy subject in order to find the usefulness of the system as a simplified gait analysis system. The joint angles were measured with reasonable accuracy, and the system showed joint angle changes that were similar to those shown in a previous report as walking speed changed. It would be necessary to examine the influence of sensor attachment position and method for more stable measurement, and also to study other parameters for gait evaluation.
Fuzzy FES controller using cycle-to-cycle control for repetitive movement training in motor rehabilitation. Experimental tests with wireless system Peer-reviewed

Naoto Miura, Takashi Watanabe, Satoru Sugimoto, Kazunori Seki, Hiroshi Kanai

Journal of Medical Engineering and Technology　35　(6-7)　314-321　2011/08

DOI： 10.3109/03091902.2011.591480 　

ISSN：0309-1902 1464-522X

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A prototype of wireless surface electrical stimulation system combined with the fuzzy FES controller was developed for rehabilitation training with functional electrical stimulation (FES). The developed FES system has three features for rehabilitation training: small-sized electrical stimulator for surface FES, wireless connection between controller and stimulators, and between controller and sensors, and the fuzzy FES controller based on the cycle-to-cycle control for repetitive training. The developed stimulator could generate monophasic or biphasic high voltage stimulus pulse and could output stimulation pulses continuously more than 20 hours with 4 AAA batteries. The developed system was examined with neurologically intact subjects and hemiplegic subjects in knee joint control. The maximum knee joint angle was controlled by regulating burst duration of stimulation pulses by the fuzzy controller. In the results of two experiments of knee extension angle control and knee flexion and extension angle control, the maximum angles reached their targets within small number of cycles and were controlled stably in the stimulation cycles after reaching the target. The fuzzy FES controller based on the cycle-to-cycle control worked effectively to reach the target angle and to compensate difference in muscle properties between subjects. The developed wireless surface FES system would be practical in clinical applications of repetitive execution of similar movements of the limbs for motor rehabilitation with FES. © 2011 Informa UK, Ltd.
A Study on Feedback Error Learning Controller for Functional Electrical Stimulation: Generation of Target Trajectories by Minimum Jerk Model Peer-reviewed

Takashi Watanabe, Keisuke Fukushima

ARTIFICIAL ORGANS　35　(3)　270-274　2011/03
Publisher: WILEY-BLACKWELL
DOI： 10.1111/j.1525-1594.2011.01223.x 　

ISSN：0160-564X

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The Feedback Error Learning controller was found to be applicable to functional electrical stimulation control of wrist joint movements in control with subjects and computer simulation tests in our previous studies. However, sinusoidal trajectories were only used for the target joint angles and the artificial neural network (ANN) was trained for each trajectory. In this study, focusing on two-point reaching movement, target trajectories were generated by the minimum jerk model. In computer simulation tests, ANNs trained with different number of target trajectories under the same total number of control iterations (50 control trials) were compared. The inverse dynamics model (IDM) of the controlled limb realized by the trained ANN decreased the output power of the feedback controller and improved tracking performance to unlearned target trajectories. The IDM performed most effectively when target trajectory was changed every one control trial during ANN training.
DEVELOPMENT OF WEARABLE GAIT EVALUATION SYSTEM A Preliminary Test of Measurement of Joint Angles and Stride Length Peer-reviewed

Takashi Watanabe, Hiroki Saito, Eri Koike, Kazuki Nitta

BIOSIGNALS 2011　245-250　2011
Publisher: SCITEPRESS

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The purpose of this study is to develop wearable sensor system for gait evaluation using gyroscopes and accelerometers for application to rehabilitation, healthcare and so on. In this paper, simultaneous measurement of joint angles of the lower limbs and stride length was tested with a prototype of wearable sensor system. The system measured the joint angles using the Kalman filter. Signals from the sensor attached on the foot were used in the stride length estimation detecting foot movement automatically. Joint angles of the lower limbs and the stride length were measured with reasonable accuracy compared to those values measured with optical motion measurement system with healthy subjects. Joint angle patterns measured in 10m walking with a healthy subject were similar to common patterns. High correlation between joint angles at some characteristic points and walking speed were also found adequately from measured data. The system was suggested to be able to detect characteristics of gait.
Tests of Wireless Wearable Sensor System in Joint Angle Measurement of Lower Limbs Peer-reviewed

Takashi Watanabe, Hiroki Saito

2011 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)　5469-5472　2011
Publisher: IEEE
DOI： 10.1109/IEMBS.2011.6091395 　

ISSN：1557-170X

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The aim of this study was to test the wireless wearable sensor system consists of inertial sensors considering application to rehabilitation. The sensor system was evaluated in measurement of hip, knee and ankle joint angles with healthy subjects comparing to those measured with a 3D motion measurement system. Then, the lower limb joint angles of elderly subjects including paralyzed subjects were measured during gait on the level floor with the sensor system. Evaluation of measured joint angles in comparison with the motion measurement system showed that mean values of the RMSE were smaller than 4 deg for all the joint angles, and mean values of the correlation coefficient were larger than 0.985 for hip and knee joint angles and about 0.90 for ankle joint angle. In measurement with elderly subjects, the sensor system showed some differences in joint angles between the paralyzed and the non-paralyzed sides.
A Clinical Trial of a Prototype of Wireless Surface FES Rehabilitation System in Foot Drop Correction Peer-reviewed

Naoto Miura, Takashi Watanabe, Kiyokazu Akasaka, Tatsuto Suzuki

2011 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)　5461-5464　2011
Publisher: IEEE
DOI： 10.1109/IEMBS.2011.6091393 　

ISSN：1557-170X

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The purpose of this study is to develop a wireless FES rehabilitation system to assist effective improvement of the lower limbs. In this report, a prototype system combined with foot drop correction and gait evaluation using wireless surface electrical stimulator and the wireless inertial sensors was developed and tested with a right hemiplegic subject. For gait evaluation, lower limb joint angles and segment angles were estimated by the Kalman filter from the data measured with wireless inertial sensors. Electrical stimulation was applied to the common peroneal nerve or the tibialis anterior muscle by detecting stimulus timing automatically from the data of wireless inertial sensor attached on the shank of the hemiplegic side. The maximum joint angle of ankle dorsiflexion of the paralyzed side at the swing phase was increased approximately to the value of the healthy side by applying the electrical stimulation. The developed system was performed well in foot drop correction and the measured data of the inertial sensors showed the characteristics and difference of paralyzed side with and without electrical stimulation using the segment angles and joint angles.
Mechanical Power of Ankle Plantar Flexion and Subjective Pain by Monophasic Electrical Stimulation Peer-reviewed

Tatsuto Suzuki, Takashi Watanabe, Ryuichi Saura, Hironobu Uchiyama

2011 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)　7234-7237　2011
Publisher: IEEE
DOI： 10.1109/IEMBS.2011.6091828 　

ISSN：1557-170X

eISSN：1558-4615

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The aim of this study was to investigate the mechanical power of the ankle plantar flexion. The investigated power of the ankle plantar flexion would help to improve effectively the FES walking system using the ankle plantar flexion for patients and aged people in slow walking. The subjective pain by electrical stimulation sometimes becomes the burden to use the FES system. We also investigated the relationship between the mechanical power in ankle plantar flexion by electrical stimulation and the subjective pain. We developed the device to measure the ankle movement by electrical stimulation against load resistance torque. The device consisted of pads to support a single lower leg, a rotational footplate with a large pulley and a vertical weight to generate the load resistance torque, and a monophasic electrical stimulator via surface electrodes. Our results showed the proportional relationship between the mechanical power of the ankle plantar flexion and the subjective pain by electrical stimulation. To generate the same level in the ankle plantar flexor power 2.75W under the maximum voluntary exertion, the subjective pain by electrical stimulation exceeded 70, which means the feeling of crying at the Face Pain Scale. This result would help the better design of the FES walking system using the ankle plantar flexion for patients and aged people.
A Preliminary Test of Measurement of Joint Angles and Stride Length with Wireless Inertial Sensors for Wearable Gait Evaluation System Peer-reviewed

Takashi Watanabe, Hiroki Saito, Eri Koike, Kazuki Nitta

COMPUTATIONAL INTELLIGENCE AND NEUROSCIENCE　2011　2011
Publisher: HINDAWI PUBLISHING CORPORATION
DOI： 10.1155/2011/975193 　

ISSN：1687-5265

eISSN：1687-5273

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The purpose of this study is to develop wearable sensor system for gait evaluation using gyroscopes and accelerometers for application to rehabilitation, healthcare and so on. In this paper, simultaneous measurement of joint angles of lower limbs and stride length was tested with a prototype of wearable sensor system. The system measured the joint angles using the Kalman filter. Signals from the sensor attached on the foot were used in the stride length estimation detecting foot movement automatically. Joint angles of the lower limbs were measured with stable and reasonable accuracy compared to those values measured with optical motion measurement system with healthy subjects. It was expected that the stride length measurement with the wearable sensor system would be practical by realizing more stable measurement accuracy. Sensor attachment position was suggested not to affect significantly measurement of slow and normal speed movements in a test with the rigid body model. Joint angle patterns measured in 10m walking with a healthy subject were similar to common patterns. High correlation between joint angles at some characteristic points and stride velocity were also found adequately. These results suggested that the wireless wearable inertial sensor system could detect characteristics of gait.
An Approach to Applying Feedback Error Learning for Functional Electrical Stimulation (FES) Controller: Computer Simulation Tests of Wrist Joint Control Peer-reviewed

Takashi Watanabe, Keisuke Fukushima

Advances in Artificial Neural Systems　2010/11

DOI： 10.1155/2010/814702 　
A Study on Feedback Error Learning Controller for FES: Generation of Target Trajectories by Minimum Jerk Model Peer-reviewed

Watanabe T, Fukushima K

Proceedings of the 15th IFESS Annual Conference　124-126　2010/09
A Preliminary Study of Muscle Fatigue Evaluation using M-waves Elicited by Additional Pulses for Rehabilitation with FES Peer-reviewed

Miura N, Watanabe T, Hiroshi K

Proceedings of the 15th IFESS Annual Conference　102-104　2010/09
Movement of Ankle Plantar flexor and Subjective Pain by Monophasic Electrical Stimulation Peer-reviewed

Suzuki T, Watanabe T, Saura R, Uchiyama H

Proceedings of the 15th IFESS Annual Conference　372-374　2010/09
Computer Simulation Tests of Feedback Error Learning Controller with IDM and ISM for Functional Electrical Stimulation in Wrist Joint Control Peer-reviewed

Takashi Watanabe, Yoshihiro Sugi

Journal of Robotics　2010/06

DOI： 10.1155/2010/908132 　
Gait Event Analysis of Normal Gait by Using a Gyroscope Attached on the Foot for Simplified Gait Evaluation Peer-reviewed

Y.Minegishi, T.Watanabe, N.Furuse

Journal of the Society of Biomechanisms　34　(1)　63-67　2010/02
Publisher: Society of Biomechanisms
DOI： 10.3951/sobim.34.63 　

ISSN：0285-0885

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In this study, we aimed to realize a simplified method of gait evaluation using a wearable sensor system intended to be used in motor function rehabilitation or daily exercise for healthcare. This paper focused on gait event analysis by using a single gyroscope attached on the instep. Characteristic points such as a turning value or a zero-crossing of the angular velocity waveform measured with the gyroscope were compared with the actual time points of gait events (heel off, toe off, heel contact and foot flat) detected by aluminum electrode sets for normal speed and slow speed walking of three healthy subjects. By using detection rules that could be applied to the offline processing, more than 90% of the gait events were detected within the difference in detection time of 50ms. For the normal speed walking, more than 90% of the gait events were detected within the difference of 42ms by detection rules both in offline and real time processing. These results showed that the characteristic points of the angular velocity waveform corresponded well to the four gait events, allowing to be detected by a single sensor.
A test of lower limb joint angle measurement method for wearable sensor system

Hiroki Saito, Takashi Watanabe, Achmad Arifin

Proc. of the 5th International Symposium on Medical, Bio- and Nano-Electronics　125-126　2010/02
A basic study on error-based parameter adjstment method for fuzzy FES controller using cycle-to-cycle control

Mio Azegami, Takashi Watanabe, Makoto Yoshizawa

Proc. of the 5th International Symposium on Medical, Bio- and Nano-Electronics　127-128　2010/02
A feasibility study of vibrotactile warning for collision prevention in a driving simulator

Makiko Sato, Takashi Watanabe, Makoto Yoshizawa

Proc. of the 5th International Symposium on Medical, Bio- and Nano-Electronics　129-130　2010/02
Improvement of feedback error learning controller for FES - a computer simulation test in wrist joint movements

Keisuke Fukushima, Takashi Watanabe, Makoto Yoshizawa

Proc. of the 5th International Symposium on Medical, Bio- and Nano-Electronics　131-132　2010/02
Comparison of two gait models for describing stability of natural sit-to-stand

Oscar David, Pena Cabra, Takashi Watanabe, Makoto Yoshizawa

Proc. of the 5th International Symposium on Medical, Bio- and Nano-Electronics　133-134　2010/02
A basic study on surface electrical stimulation system for motor rehabilitation

Naoto Miura, Satoru Sugimoto, Takashi Watanabe, Kazunori Seki, Hiroshi Kanai

Proc. of the 5th International Symposium on Medical, Bio- and Nano-Electronics　251-252　2010/02
Preliminary Test of Muscle Fatigue Evaluation Using M-Wave for Motor Rehabilitation with Electrical Stimulation Peer-reviewed

N.Miura, T.Watanabe, H.Kanai

Proceedings of the 14th IFESS Annual Conference　99-101　2009/09
A Computer Simulation Test of the Improvement of FES Controller Using Feedback Error Learning Scheme on 2-DOF Wrist Joint Movements Peer-reviewed

Keisuke Fukushima, Takashi Watanabe, Makoto Yoshizawa

Proceedings of the 14th IFESS Annual Conference　113-116　2009/09
Preliminary Tests of a Practical Fuzzy FES Controller Based on Cycle-to-Cycle Control in the Knee Flexion and Extension Control Peer-reviewed

Takashi Watanabe, Tomoya Masuko, Achmad Arifin

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E92D　(7)　1507-1510　2009/07
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1587/transinf.E92.D.1507 　

ISSN：0916-8532

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The fuzzy controller based on cycle-to-cycle control with output value adjustment factors (OAF) was developed for restoring gait of paralyzed subjects by using functional electrical stimulation (FES). Results of maximum knee flexion and extension controls with neurologically intact Subjects Suggested that the OAFs would be effective in reaching the target within small number of cycles and in reducing the error after reaching the target. Oscillating responses between cycles were also suppressed. The fuzzy controller was expected to be examined to optimize the OAFs, with more subjects including paralyzed patients for clinical application.
A Basic Study on Stimulation Pulse Width Determination for Dynamic Presentation of Electrocutaneous Sensation Patterns Peer-reviewed

Yuka Minegishi, Takashi Watanabe, Makoto Yoshizawa

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E92D　(6)　1328-1330　2009/06
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1587/transinf.E92.D.1328 　

ISSN：0916-8532

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In this study, we aimed to realize a method of presenting dynamic electrocutaneous sensation patterns as a user interface for persons with disabilities. In this study, the previously used pulse width (200 mu s) was used in pattern recognition testing on the forearm and was compared with the short pulse width (80 mu s) used for stimulation. A cathodic pulse with a frequency of 100pps, which was suggested to be suitable in our previous study, was used. Experimental results on neurologically intact subjects suggested that the previously used pulse width was suitable and that a short pulse width would not be effective for stabilizing the stimulation amplitude or for improving the pattern recognition ability of our method.
An Effective Method on Applying Feedback Error Learning Scheme to Functional Electrical Stimulation Controller Peer-reviewed

Takashi Watanabe, Kenji Kurosawa, Makoto Yoshizawa

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E92D　(2)　342-345　2009/02
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1587/transinf.E92.D.342 　

ISSN：0916-8532

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A Feedback Error Learning (FEL) scheme was found to be applicable to joint angle control by Functional Electrical Stimulation (FES) in our previous study. However, the FEL-FES controller had a problem in learning of the inverse dynamics model (IDM) in some cases. In this paper, methods of applying the FEL to FES control were examined in controlling 1-DOF movement of the wrist joint stimulating 2 muscles through computer simulation under several control conditions with several subject models. The problems in applying FEL to FES controller were suggested to be in restricting stimulation intensity to positive values between the minimum and the maximum intensities and in the case of very small output values of the IDM. Learning of the IDM was greatly improved by considering the IDM output range with setting the minimum ANN output value in calculating ANN connection weight change.
Ankle and knee joint angle measurements during gait with wearable sensor system for rehabilitation Peer-reviewed

Hiroki Saito, Takashi Watanabe, Achmad Arifin

IFMBE Proceedings　25　(9)　506-509　2009

DOI： 10.1007/978-3-642-03889-1-134 　

ISSN：1680-0737

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A method of joint angle measurement during gait using wearable sensors for rehabilitation was studied in this paper. The method corrected joint angles measured by gyroscopes using joint angles measured by accelerometers with Kalman filter. Although gyroscopes could measure joint angles, their offset drift caused error in measurement of joint angles. At first, we made up small sensor units consist of a gyroscope and an accelerometer. Then, the method was validated with the developed sensor units in measurement of ankle and knee joint angles of three healthy subjects under walking on short distance pathway and on treadmill for long time. The measured joint angles were compared with reference joint angles measured with optical motion measurement system simultaneously. The result for short distance walking showed low RMS errors and high correlation coefficients (3.19deg and 0.918 for the ankle joint, 2.98deg and 0.993 for the knee joint in average). The result for treadmill walking also showed low RMS errors and high correlation coefficients (3.04deg and 0.960 for the ankle, 4.19deg and 0.994 for the knee in average). Although the measurement accuracy decreased in some of trials of a specific subject because of sensor attachment position, the experimental results suggested that joint angle could be measured with good accuracy independent of measurement period of time, walking speeds and subjects. © 2009 Springer-Verlag.
A test of stride length measurement with an accelerometer and a gyroscope attached on the foot Peer-reviewed

T. Watanabe, Y. Minegishi

IFMBE Proceedings　25　(9)　502-505　2009

DOI： 10.1007/978-3-642-03889-1-133 　

ISSN：1680-0737

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Simplified gait analysis system using wearable sensors based on accelerometers and gyroscopes were focused in this study for rehabilitation of motor function and daily exercise for health. In this paper, a preliminary test of stride length estimation for each step using an accelerometer and a gyroscope attached on the foot was performed with two neurologically intact subjects. Reference signals were obtained from 3D motion analysis system. Although error in stride length estimation varied between subjects and between trials, mean absolute error was acceptable (less than about 10%) except for the 1st step (start of walking) of one subject. For subject B, the mean absolute errors for the 2nd step were less than 5% for all the trials. Experimental results also suggested that precise measurement of tilt angle of the foot and determination of appropriate integration period would realize practical estimation of the stride length using only inertial sensors. Since the sensor unit used in the experiment was not packaged all in one, development of a sensor unit and further tests with the developed sensor would be in the next work. © 2009 Springer-Verlag.
A Basic Experiment of Different Pulse Width Stimulation for Information Presenting Method Using Dynamic Electro-cutaneous Sensation Patterns Peer-reviewed

Yuka Minegishi, Takashi Watanabe, Makoto Yoshizawa

International Symposium on Nano-Biomedical Engineering　102-103　2008/10

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Natonal Cheng Kung University, Tainan, Taiwan,
A Preliminary Test of Modified Applying Methods of Feedback Error Learning for FES Control Peer-reviewed

Takashi Watanabe, Kenji Kurosawa

Proceedings of the 13t IFESS Annual Conference　162-164　2008/09
Detection of Gait Phases with Piezoelectric Gyroscope under Different Walking Speed Conditions Peer-reviewed

Norio Furuse, Takashi Watanabe

Proceedings of the 13t IFESS Annual Conference　97-99　2008/09
A feasibility study of fuzzy FES controller based on cycle-to-cycle control: An experimental test of knee extension control Peer-reviewed

Takashi Watanabe, Tomoya Masuko, Achmad Arifin, Makoto Yoshizawa

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E91D　(3)　865-868　2008/03
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1093/ietisy/e91-d.3.865 　

ISSN：0916-8532

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Functional Electrical Stimulation (FES) can be effective in assisting or restoring paralyzed motor functions. The purpose of this study is to examine experimentally the fuzzy controller based on cycle-to-cycle control for FES-induced gait. A basic experimental test was performed on controlling maximum knee extension angle with normal subjects. In most of control trials, the joint angle was controlled well compensating changes in muscle responses to electrical stimulation. The results show that the fuzzy controller would be practical in clinical applications of gait control by FES. An automatic parameter tuning would be required practically for quick responses in reaching the target and in compensating the change in muscle responses without causing oscillating responses.
Functional Electrical Stimulation (FES) for Motor Disabled Patients

Takashi Watanabe

Book of abstract, 3rd International Symposium on Medical, Bio- and Nano-Electronics　35-42　2008/03
Application of Knowledge Engineering and Fuzzy System in Realizing Cycle-to-Cycle Control Method for Swing Phase of FES-induced Gait

A. Arifin, T. Watanabe, T. Masuko

Book of abstract, 3rd International Symposium on Medical, Bio- and Nano-Electronics　43-51　2008/03
Cycle-to-Cycle制御法に基づくファジィFES制御器による膝関節制御の実験的検討 Peer-reviewed

増子知也, 渡邉高志, Achmad Arifin, 吉澤誠

Transactions of the Japanese Society for Medical and Biological Engineering　45　(4)　313-318　2007/12

DOI： 10.11239/jsmbe.45.313 　
Basic Experiments of Physiological Properties for Information Presenting Method Using Dynamic Electro-cutaneous Sensation Patterns Peer-reviewed

Yuka Minegishi, Takashi Watanabe, Makoto Yoshizawa

International Journal of Bioelectromagnetism　9　(1)　30-31　2007/10
Evaluation of adaptation to visually induced motion sickness based on the maximum cross-correlation between pulse transmission time and heart rate Peer-reviewed

Norihiro Sugita, Makoto Yoshizawa, Makoto Abe, Akira Tanaka, Takashi Watanabe, Shigeru Chiba, Tomoyuki Yambe, Shin-ichi Nitta

JOURNAL OF NEUROENGINEERING AND REHABILITATION　4　2007/09
Publisher: BIOMED CENTRAL LTD
DOI： 10.1186/1743-0003-4-35 　

ISSN：1743-0003

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Background: Computer graphics and virtual reality techniques are useful to develop automatic and effective rehabilitation systems. However, a kind of virtual environment including unstable visual images presented to wide field screen or a head mounted display tends to induce motion sickness. The motion sickness induced in using a rehabilitation system not only inhibits effective training but also may harm patients' health. There are few studies that have objectively evaluated the effects of the repetitive exposures to these stimuli on humans. The purpose of this study is to investigate the adaptation to visually induced motion sickness by physiological data. Methods: An experiment was carried out in which the same video image was presented to human subjects three times. We evaluated changes of the intensity of motion sickness they suffered from by a subjective score and the physiological index rho(max), which is defined as the maximum cross-correlation coefficient between heart rate and pulse wave transmission time and is considered to reflect the autonomic nervous activity. Results: The results showed adaptation to visually-induced motion sickness by the repetitive presentation of the same image both in the subjective and the objective indices. However, there were some subjects whose intensity of sickness increased. Thus, it was possible to know the part in the video image which related to motion sickness by analyzing changes in. max with time. Conclusion: The physiological index,. max, will be a good index for assessing the adaptation process to visually induced motion sickness and may be useful in checking the safety of rehabilitation systems with new image technologies.
Gyro-mouse for the disabled: 'Click' and 'position' control of the mouse cursor Peer-reviewed

Gwang-Moon Eom, Kyeong-Seop Kim, Chul-Seung Kim, James Lee, Soon-Cheol Chung, Bongsoo Lee, Hiroki Higa, Norio Furuse, Ryoko Futami, Takashi Watanabe

INTERNATIONAL JOURNAL OF CONTROL AUTOMATION AND SYSTEMS　5　(2)　147-154　2007/04
Publisher: INST CONTROL ROBOTICS & SYSTEMS, KOREAN INST ELECTRICAL ENGINEERS
ISSN：1598-6446

eISSN：2005-4092

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This paper describes a 'gyro-mouse', which provides a new human-computer interface (HCl) for persons who are disabled in their upper extremities, for handling the mouse-click and mouse-move function. We adopted the artificial neural network to recognize a quick-nodding pattern of the disabled person as the gyro-mouse click. The performance of our gyro-mouse was evaluated by three indices that include 'click recognition rate', 'error in cursor position control', and 'click rate per minute' on a target box appearing at random positions. Although it turned out that the average error in cursor positioning control was 1.4-1.5 times larger than that of optical mouse control, and the average click rate per minute was 40% of the optical mouse, the overall click recognition rate was 93%. Moreover, the click rate per minute increased from 35.2% to 44% with repetitive trials. Hence, our suggested gyro-mouse system can be used to provide a new user interface tool especially for those persons who do not have full use of their upper extremities.
Feasibility study of transmission of information by presenting dynamic cutaneous sensation patterns elicited by surface electrical stimulation Peer-reviewed

Yuki Sato, Takashi Watanabe, Makoto Yoshizawa, Nozomu Hoshimiya

Journal of the Society of Biomechanisms　31　(1)　30-35　2007/02/01
Publisher: Society of Biomechanisms Japan (SOBIM)
DOI： 10.3951/sobim.31.30 　

ISSN：0285-0885

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The purpose of this study was to develop a method of transmission of information by using cutaneous sensation elicited by electrical stimulation. In this paper, we proposed to present dynamically cutaneous sensation patterns such as characters or graphic symbols that could be understood intuitively. First, a basic design of stimulation electrode was determined experimentally. Then, basic 16 presentation patterns were examined in pattern recognition experiments with neurologically intact subjects. As one of reasons of misrecognition, remaining sensation after electrical stimulation was considered. Therefore, inter stimulus interval (ISI) between two presentation patterns was determined experimentally. Based on results of the first recognition experiments and determined ISI, modified 14 patterns were examined in the recognition experiments. Correct recognition ratio was 70.7∼90% on 4 of 6 subjects. It was higher than or equal to that of previous research works, in which only 4 patterns were tested experimentally. In addition, the correct recognition ratio was also expected to be about 90 % in average if patterns including diagonal lines were removed as patterns used in the previous study. The method proposed in this paper was expected to be effective in recognition of many presentation patterns. Optimization of stimulating electrode and parameters of electrical stimulation for pattern presentation, and examination of pattern presentation for practical characters and graphic symbols would be required.
An Experimental Test of Fuzzy Controller Based on Cycle-to-Cycle Control for FES-induced Gait: Knee Joint Control with Neurologically Intact Subjects Peer-reviewed

T. Watanabe, A. Arifin, T. Masuko, M. Yoshizawa

11TH MEDITERRANEAN CONFERENCE ON MEDICAL AND BIOLOGICAL ENGINEERING AND COMPUTING 2007, VOLS 1 AND 2　16　(1-2)　647-+　2007
Publisher: SPRINGER-VERLAG BERLIN
ISSN：1680-0737

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Functional Electrical Stimulation (FES) can be effective in assisting or restoring paralyzed motor functions caused by the spinal cord injury or the celebrovascular disease. The purpose of this study was to develop a control method of gait induced by FES. We had proposed a fuzzy control system based on cycle-to-cycle control for controlling hip, knee and ankle joints during the swing phase of FES-induced gait and evaluated it in computer simulation studies. In this report, the fuzzy controller was tested experimentally in controlling maximum knee extension angle stimulating the vastus muscles using surface electrodes with neurologically intact subjects. The fuzzy controller worked properly in regulating stimulation burst duration time and the maximum knee extension angle was controlled well. The experimental results suggested that the fuzzy controller would be practical in clinical applications for the control of FES-induced gait. However, it was also suggested that electrical stimulation with large burst duration time or muscle fatigue caused a change in muscle response. Including automatic controller parameter tuning during a gait control and further experimental tests were necessary for practical applications.
A Study on Sensing System of Lower Limb Condition with Piezoelectric Gyroscopes: Measurements of Joint Angles and Gait Phases Peer-reviewed

Norio Furuse, Takashi Watanabe

11TH MEDITERRANEAN CONFERENCE ON MEDICAL AND BIOLOGICAL ENGINEERING AND COMPUTING 2007, VOLS 1 AND 2　16　(1-2)　689-+　2007
Publisher: SPRINGER-VERLAG BERLIN
ISSN：1680-0737

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Functional electrical stimulation (FES) training of paralyzed muscles is effective for incomplete spinal cord injured patients in the early period of the rehabilitation process. Information of lower limb joint angles and gait phases are very important to assist walking and to restore motor function with FES. It is considered that a small and inexpensive gyroscope is useful to construct a practical sensor system in clinical. In this paper, we examined the simultaneous measurement method of the lower limb joint angles and the gait phases by using the gyroscopes. From the result of the walking analysis with normal subjects, it was indicated that the sensor system could measure the joint angles with sufficient accuracy and could detect practicably the swing phase and the stance phase without mistake. Therefore, the sensing system of lower limb condition with appropriate accuracy that could be used in clinical would be constructed compactly at inexpensive by using the gyroscopes.
FES Control Method of the Swing Phase of Hemiplegic Gait based on Cycle-to-Cycle Control: Model Simulation Considering Floor Reaction Force Peer-reviewed

Satoshi Shibata, Takashi Watanabe, Achmad Arifin, Makoto Yoshizawa, Nozomu Hoshimiya

Transactions of the Japanese Society for Medical and Biological Engineering　44　(4)　687-695　2006/12
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.44.687 　

ISSN：1347-443X

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ataOur previous computer simulation study showed that the fuzzy controller based on cycle-to-cycle control would be useful in controlling the swing phase of hemiplegic gate using functional electrical stimulation (FES). However, a simplified musculoskeletal model of a swing leg with the floor reaction force eliminated was used in the previous study. In this paper, a musculoskeletal model consisting of the stance and swing legs with a floor model was developed first. Then, the fuzzy controller for controlling the swing phase was examined using computer simulation of the developed model including the toe off and initial contact. Computer simulation results showed that the fuzzy controller and the stimulation schedule developed in our previous work were adequate, and that modifying the schedule considering the strength of the plantar flexion of the ankle joint would be more effective for improving responses at an early stage of control. A control method based on using electromyograms (EMGs)was also discussed. The fuzzy controller and a previously created EMG-based stimulation schedule, which was unable to control the swing phase, were modified by changing the role of the rectus femoris muscle. The modified fuzzy controller with a new EMG-based stimulation schedule was found to develop the swing phase movement appropriately.
Gait Re-education System for Incomplete Spinal Cord Injured Patients -Measurement of Hip Joint Angle by Piezoelectric Gyroscope- Peer-reviewed

N.Furuse, T.Watanabe, N.Hoshimiya

Proceedings of the 11th IFESS Annual Conference　228-230　2006/09
A basic study on upper limb control by FES using feedback error learning with IDM and ISM Peer-reviewed

Y.Sugi, T.Watanabe, K.Kurosawa, M.Yoshizawa, N.Hoshimiya

Proceedings of the 11th IFESS Annual Conference　181-183　2006/09
A Basic Study of Fuzzy Controller for Cycle-to-Cycle Control of Knee Joint Movements of FES Swing: First Experimental test with a Normal Subject Peer-reviewed

T.Masuko, T.Watanabe, A.Arifin, M.Yoshizawa, N.Hoshimiya

Proceedings of the 11th IFESS Annual Conference　172-174　2006/09
Nonlinear FES control of knee joint by inversely compensated feedback system Peer-reviewed

GM Eom, JK Lee, KS Kim, T Watanabe, R Futami

INTERNATIONAL JOURNAL OF CONTROL AUTOMATION AND SYSTEMS　4　(3)　302-307　2006/06
Publisher: INST CONTROL AUTOMATION & SYSTEMS ENGINEERS-KOREAN INST ELECTRICAL ENG
ISSN：1598-6446

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The aim of applying Functional Electrical Stimulation (FES) is to restore a person's motor function by directly supplying the controlled electrical currents to the site of the paralyzed muscles. However, most clinically utilized FES systems have adapted an open-loop control scheme. Recently the closed-loop control scheme has been considered for setting up the FES system, but due to the inherent nonlinearities in the musculoskeletal system, the nonlinearities were not fully compensated and it caused the oscillatory responses for tracking the output variables. In this study, a, nonlinear controller model that has two inverse compensation units is proposed with the compromising feedback linearization method and this will eventually be used to design the FES control system for stimulating a knee joint musculoskeletal system.
Design of fuzzy controller of the cycle-to-cycle control for swing phase of hemiplegic gait induced by FES Peer-reviewed

A Arifin, T Watanabe, N Hoshimiya

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E89D　(4)　1525-1533　2006/04
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1093/ietisy/e89-d.4.1525 　

ISSN：0916-8532

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The goal of this study was to design a practical fuzzy controller of the cycle-to-cycle control for multi-joint movements of swing phase of functional electrical stimulation (FES) induced gait. First, we designed three fuzzy controllers (a fixed fuzzy controller, a fuzzy controller with parameter adjustment based on the gradient descent method, and a fuzzy controller with parameter adjustment based on a fuzzy model) and two PID controllers (a fixed PID and an adaptive PID controllers) for controlling two-joint (knee and ankle) movements. Control capabilities of the designed controllers were tested in automatic generation of stimulation burst duration and in compensation of muscle fatigue through computer simulations using a musculo-skeletal model. The fuzzy controllers showed better responses than the PID controllers in the both control capabilities. The parameter adjustment based on the fuzzy model was shown to be effective when oscillating response was caused due to the inter-subject variability. Based on these results, we designed the fuzzy controller with the parameter adjustment realized using the fuzzy model for controlling three-joint (hip, knee, and ankle) movements. The controlled gait pattern obtained by computer simulation was not significantly different from the normal gait pattern and it could be qualitatively accepted in clinical FES gait control. The fuzzy controller designed for the cycle-to-cycle control for multi-joint movements during the swing phase of the FES gait was expected to be examined clinically.
A Test of Stimulation Schedules for the Cycle-to-Cycle Control of Multi-joint Movements in Swing Phase of FES-induced Hemiplegic Gait Peer-reviewed

Achamad Arifin, Takashi Watanabe, Makoto Yoshizawa, N.Hoshimiya

Journal of the Society of Biomechanisms　30　(1)　31-35　2006/02
Publisher: Society of Biomechanisms Japan (SOBIM)
DOI： 10.3951/sobim.30.31 　

ISSN：0285-0885

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This paper described a computer simulation test of six different stimulation schedules for the cycle-to-cycle control of swing phase of functional electrical stimulation (FES) induced hemiplegic gait. The stimulation schedules were evaluated in controlling the hip, the knee and the ankle joint movements on the point of view of acceptable quality of the gait that was similar to the natural gait pattern. Five stimulation schedules were knowledge-based stimulation schedules and one stimulation schedule was an EMG-based stimulation schedule. Two acceptable stimulation schedules were found by the evaluation. Results of this study showed that combination of the timing pattern of muscle activation and knowledge of joint movements and muscle function is necessary in design of stimulation schedule for FES gait. Co-activation of the ilopsoas, the hamstrings and the vastus muscle at the beginning of swing phase and that of the tibialis anterior and the soleus at the end of swing phase were found to be effective in controlling swing phase. The knowledge-based generation of stimulation schedule would be effective and necessary in clinical application.
A Study on a Recognition Method of Specific Motions by Processing Outputs of Artificial Neural Networks with Different Input Signals Peer-reviewed

Takashi Watanabe, Taiki Fujihara, Hajime Murakami, Norio Furuse, Makoto Yoshizawa, Nozomu Hoshimiya

Transactions of the Japanese Society for Medical and Biological Engineering　43　(4)　544-550　2005/12
Publisher: None
DOI： 10.11239/jsmbe.43.544 　
Simplified Measurement Method of Lower Limb Joint Angles by using Piezoelectric Gyroscopes Peer-reviewed

Norio Furuse, Takashi Watanabe, Nozomu Hoshimiya

Transactions of the Japanese Society for Medical and Biological Engineering　43　(4)　538-543　2005/12
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe.43.538 　

ISSN：1347-443X

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The joint angles of the lower limbs are important parameters in evaluating the ability and stability of walking when training to walk or control FES gait. In this study, a simplified measurement method for lower limb joint angles that uses gyroscopes attached to the thigh, the shank and the foot is proposed. The method was examined by measuring the leg joint angles of three neurologically intact subjects when walking. The results showed a high correlation between the joint angles measured with the commercially available electric goniometer and those by the proposed method. Appropriate attachment positions of the sensors were also suggested from the experimental results. The proposed simplified measurement method for lower limb joint angles is expected to be effective for walking training or FES gait restoration at clinical sites.
Joint angle control by FES using a feedback error learning controller Peer-reviewed

K Kurosawa, R Futami, T Watanabe, N Hoshimiya

IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING　13　(3)　359-371　2005/09
Publisher: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI： 10.1109/TNSRE.2005.847355 　

ISSN：1534-4320

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The feedback error learning (FEL) scheme was studied for a functional electrical stimulation (FES) controller. This FEL controller was a hybrid regulator with a feedforward and a feedback controller. The feedforward controller learned the inverse dynamics of a controlled object from feedback controller outputs while control. A four-layered neural network and the proportional-integral-derivative (PID) controller were used for each controller. The palmar/dorsi-flexion angle of the wrist was controlled in both computer simulation and FES experiments. Some controller parameters, such as the learning speed coefficient and the number of neurons, were determined in simulation using an artificial forward model of the wrist. The forward model was prepared by using a neural network that can imitate responses of subject's wrist to electrical stimulation. Then, six able-bodied subjects' wrist was controlled with the FEL controller by delivering stimuli to one antagonistic muscle pair. Results showed that the FEL controller functioned as expected and performed better than the conventional PID controller adjusted by the Chien, Hrones and Reswick method for a fast movement with the cycle period of 2 s, resulting in decrease of the average tracking error and shortened delay in the response. Furthermore, learning iteration was shortened if the feedforward controller had been trained in advance with the artificial forward model.
Computer simulation test of fuzzy controller for the cycle-to-cycle control of knee joint movements of swing phase of FES gait Peer-reviewed

A Arifin, T Watanabe, N Hoshimiya

IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS　E88D　(7)　1763-1766　2005/07
Publisher: IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG
DOI： 10.1093/ietisy/e88-d.7.1763 　

ISSN：0916-8532

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We proposed a fuzzy control scheme to implement the cycle-to-cycle control for restoring swing phase of gait using functional electrical stimulation (FES). We designed two fuzzy controllers for the biceps femoris short head (BFS) and the vastus muscles to control flexion and extension of the knee joint during the swing phase. Control capabilities of the designed fuzzy controllers were tested and compared to proportional-integral-derivative (PID) and adaptive PID controllers in automatic generation of stimulation burst duration and compensation of muscle fatigue through computer simulations using a musculo-skeletal model. Parameter adaptations in the adaptive PID controllers did not significantly improve the control performance of the PID controllers. The fuzzy controllers were superior to the PID and adaptive PID controllers under several subject conditions and different fatigue levels. These results showed the fuzzy controller would be suitable to implement the cycle-to-cycle control of FES-induced gait.
A test of multichannel closed-loop FES control on the wrist joint of a hemiplegic patient Peer-reviewed

Watanabe T, Matsudaira T, Hoshimiya N, Handa Y

Proceedings of the 10th IFESS Annual Conference　56-58　2005/07
COMPUTER SIMULATION FOR MULTICHANNEL CLOSED-LOOP FES CONTROL OF THE WRIST JOINT Peer-reviewed

T. Watanabe, M. Otsuka, M. Yoshizawa, N. Hoshimiya

Proceedings of 8th Vienna International Workshop on Functional Electrical Stimulation　138-141　2004/09
Gait Re-education System for Incomplete Spinal Cord Injured Patients - Measurement of Leg Joint Angles by Piezoelectric Gyroscope - Peer-reviewed

Norio Furuse, Takashi Watanabe, Nozomu Hoshimiya

Proceedings of the 9th IFESS Annual Conference　395-397　2004/09
Wearable data collection system for online gait stability analysis Peer-reviewed

T Karcnik, T Watanabe, R Futami, N Hoshimiya

NEUROMODULATION　7　(3)　223-229　2004/07
Publisher: BLACKWELL PUBLISHING INC
DOI： 10.1111/j.1094-7159.2004.04202.x 　

ISSN：1094-7159

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We had shown in our previous research that the stability assessment and control are essential for generation of faster and more energy efficient functional electrical stimulation (FES) and/or crutch-assisted gait. The objective of our recent research work has been to design a wearable and portable system for gait stability analysis with online capabilities that is also applicable to crutch-assisted gait modes. The developed wearable stability assessment system for as yet only biped gait consists of foot switches and goniometers attached to the leg joints. The instantaneous static and dynamic stability is, within the wearable system, assessed from the trajectory of the estimated body center of gravity (COG(HAT)) and the supporting area shape/size as derived from step length and foot-floor contact state. We used motion analysis system data as reference for testing the wearable system accuracy. The wearable system was tested on five healthy subjects and one above-knee amputee. It proved to be reasonably accurate if compared to the classical, motion analysis system based method. However, additional work is required to port the system to the FES assisted and/or crutch assisted gait.
Gait Re-education System for Incomplete Spinal Cord Injured Patients - Development of Gait Measurement System - Peer-reviewed

N.Furuse, T.Watanabe, I.Cikajo, T.Bajd, N.Hoshimiya

Proceedings of the 8th IFESS Annual Conference　198-201　2003/07
Feedback Error Learning for Controlling 1-DOF Joint Angle: Model Simulation and Experiment Peer-reviewed

K.Kurosawa, R.Futami, T.Watanabe, N.Hoshimiya

Proceedings of the 8th IFESS Annual Conference　65-68　2003/07
A method of multichannel PID control of two-degree-of-freedom wrist joint movements by functional electrical stimulation Invited

Takashi Watanabe, Kan Iibuchi, Kenji Kurosawa, Nozomu Hoshimiya

Systems and Computers in Japan　34　(5)　25-36　2003/05

DOI： 10.1002/scj.10298 　

ISSN：0882-1666

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In restoring motor functions of paralyzed extremities by functional electrical stimulation (FES), determination of stimulus intensities of many muscles in multichannel control is an ill-posed problem because of redundancy in the input (stimulus intensity)-output (joint angle) relationship of the musculoskeletal system. In this paper, we use a multi-input and multi-output PID controller and propose a parameter determination method for the controller, which can solve the ill-posed problem in closed-loop control. In the parameter determination process, the stimulus intensity-joint angle characteristics of all muscles controlled were measured first. The elements of the matrix that transforms stimulus intensities into joint angles were determined by linear approximation of the measured characteristics. Then a generalized inverse matrix of the transformation matrix was calculated. The generalized inverse matrix and an expanded CHR method were used to determine the parameters of the PID controller. The PID controller was examined in tracking control on several trajectories of two-degree-of-freedom movement of the wrist joint with neurologically intact subjects. Electrical stimulation was applied to four muscles relating to the wrist joint movements through surface electrodes. The tracking control was achieved generally with good performance under different conditions of the gravitational effect. The new method proposed in this paper was found to provide a solution of the ill-posed problem. Multichannel closed-loop FES control of the wrist joint could be realized with this method. © 2003 Wiley Periodicals, Inc.
Control Command Detection by Artificial Neural Network from Lower Limb Movements for Hemiplegic Patients Using FES Peer-reviewed

Takashi WATANABE, Shiho YAMAGISHI, Hajime MURAKAMI, Norio FURUSE, Nozomu HOSHIMIYA

The Transactions of the Institute of Electronics, Information and Communication Engineering　J86-D-II　(2)　371-375　2003/02
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0915-1923
An approach to real-time parameter determination of the multichannel closed-loop FES controller Peer-reviewed

T Watanabe, T Matsudaira, K Kurosawa, N Hoshimiya, Y Handa

IEEE EMBS APBME 2003　232-233　2003
Publisher: IEEE

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We have developed the multichannel closed loop FES controller using the PID control for multi-joint control and/or several degrees of freedom of movement control stimulating several muscles. Although the method was proved to be effective, it sometimes caused undesirable responses such as oscillations of joint angles because of strong nonlinearity of the input-output characteristics of electrically stimulated muscles. In this paper, a method of real-time parameter determination for the controller was examined. Controller parameters were determined based on stimulus intensities applied just before each adjustment of stimulation intensities. The method was effective in reducing undesirable oscillations during closed loop FES control without trial and error adjustment of controller parameters.
Fuzzy controller for cycle-to-cycle control of swing phase of FES-induced hemiplegic gait: A computer simulation in two-joints control Peer-reviewed

A Arifin, T Watanabe, N Hoshimiya

PROCEEDINGS OF THE 25TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-4　25　1519-1522　2003
Publisher: IEEE
ISSN：1094-687X

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This paper described a test of fuzzy controller for controlling knee and ankle movements of swing phase of FES-induced hemiplegic gait. We developed five fuzzy controllers to control electrical stimulation for the hamstrings, the quadriceps, the gastrocnemius medialis, the tibialis anterior and the soleus muscles. The fuzzy controllers regulated burst durations of stimulation pulse trains to maintain certain maximum angles of knee flexion, knee extension, ankle plantar flexion, and ankle dorsiflexion and to prepare good initial contact. Capabilities of fuzzy controller in automatic generation of stimulation burst duration and compensating muscle fatigue were tested by computer simulation using musculo-skeletal model. The fuzzy controller generated standard burst duration in automatic generation of stimulation burst duration in a few cycles and compensated muscle fatigue fast.
Pitch pattern generation using multispace probability distribution HMM Peer-reviewed

Hironori Nakatani, Takashi Watanabe, Shigeo Ohba, Nozomu Hoshimiya

Systems and Computers in Japan　33　(6)　62-72　2002/06/15

DOI： 10.1002/scj.1133 　

ISSN：0882-1666

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A scheme for simultaneously modeling and generating a pitch pattern and a spectral sequence on the basis of a hidden Markov model (HMM) is presented. Since a pitch pattern is expressed as a time series of voiced intervals taking continuous values and voiceless intervals without values, it cannot be modeled by the usual HMM. This paper proposes a scheme for modeling a pitch and a spectrum integrally with characteristic parameters that combine pitch parameters and spectral parameters by applying an HMM based on a multispace probability distribution (multispace probability distribution HMM: MSD-HMM). In addition, a context clustering scheme based on decision trees in the MSD-HMM is derived, and a scheme for constructing the model while taking account of the variation factors of the pitch and the spectrum is presented. In addition, it is shown that pitch patterns and spectral sequences approximating real voice can be generated by using the parameter generation scheme based on the maximum likelihood criterion. © 2002 Wiley Periodicals, Inc. Syst. Comp. Jpn.
Classification of nerve action potentials for estimation of sensory unit activity

Hironori Nakatani, Takashi Watanabe, Shigeo Ohba, Nozomu Hoshimiya

Systems and Computers in Japan　33　(6)　44-52　2002/06/15
Publisher: Wiley
DOI： 10.1002/scj.1131 　

ISSN：0882-1666

eISSN：1520-684X
A STUDY ON RELEVANCE OF SKIN IMPEDANCE TO ABSOLUTE THRESHOLD FOR STABILIZATION OF CUTANEOUS SENSATION ELICITED BY ELECTRIC CURRENT STIMULATION Peer-reviewed

Takashi WATANABE, Shun'ichi WATANABE, Kazuhiro YOSHINO, Ryoko FUTAMI, Nozomu HOSHIMIYA

Biomechanism　16　61-73　2002/06
Publisher: Society of Biomechanisms Japan (SOBIM)
DOI： 10.3951/biomechanisms.16.61 　

ISSN：1348-7116

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This study focused on stabilizing the sensations elicited by electrical stimulation applied to the skin through surface electrodes, a technique widely used in sensory feedback research. The relationship between absolute threshold (the minimum stimulus amplitude that causes sensation) and the parameters of an electrical equivalent circuit for skin impedance was examined with neurologically intact subjects. Electric current pulse stimulation at 100 Hz frequency and pulse widths between 0.08 and 0.5 ms was used to elicit a cutaneous sensation. The electrical equivalent circuit for skin impedance consisted of resistance Rp and capacitance Cp connected in parallel, plus resistance Rs connected in series to both. First, we estimated the parameters of the equivalent circuit by the skin impedance measured with sinusoidal signals (Rps and Cps), and we examined their relevance to the absolute threshold. For Ag-AgCl electrodes used with electroconductive paste, variations over time of the frequency characteristics of Rps and Cps were found to be similar to the changes caused by repeatedly stripping the skin. Values of Cps and Rps at 10 Hz were found to relate to the absolute threshold with high correlation coefficients. For a solid-gel Ag-AgCl electrode, changes of absolute threshold, Rps and Cps caused by increasing size of the solid-gel electrode were similar to variations over time obtained using electrodes with electroconductive paste. Correlations between the threshold and values of Rps and Cps at 10 Hz were also observed. Next, we estimated the parameters of the equivalent circuit by measuring stimulus pulse current and voltage waves of square-wave stimulus pulses using solid-gel electrodes (Rps and Cpr). We then examined their relevance to the absolute threshold. The absolute threshold increased with repeated electrical stimulation to the skin and decreased after adequate rest with no electrical stimulation. The value of Rpr decreased with repeated electrical stimulation and increased after rest, while the value of Cpr did not change. These variations became minor after preparation of the skin for removing the stratum corneum. A significant correlation between Rpr and the absolute threshold was observed. These results show that electrical stimulation to the stratum corneum affects both absolute threshold and skin impedance; they also indicate that real-time evaluation is important for stabilizing cutaneous sensation elicited by electrical stimulation. The relevance of Rp to the threshold was shown in both methods that were used to estimate the parameters. Possible reasons for decreasing Rp were an increase of ionic conductivity due to osmosis of electroconductive paste into the stratum corneum or an increase of electric charge in the stratum corneum due to charge transfer by electrical stimulation through the skin. The increase of the threshold amplitude was considered to be the result of broadened current path due to increases of ionic or electric conductivities in the stratum corneum. It is necessary to clarify the mechanism of the relationship between the threshold and impedance parameters in order to develop a technique for stabilizing electrocutaneous sensation.
Wrist Joint Control by Multichannel Closed-loop FES system: System Construction and First Clinical Test Peer-reviewed

T.Watanabe, T.Matsudaira, K.Kurosawa, T.Fujii, R.Futami, N.Hoshimiya, M.Ichie

Proceedings of the 7th IFESS Annual Conference　265-267　2002/06
Training of Stance Phase during FES Assisted Walking - Detection of Stance Phase by Artificial Neural Network - Peer-reviewed

N.Furuse, I.Cikajo, T.Bajd, T.Watanabe, N.Hoshimiya

Proceedings of the 7th IFESS Annual Conference　63-65　2002/06
Wearable System For Gait Stability Analysis Peer-reviewed

T.Karcnik, T.Watanabe, R.Futami, N.Hoshimiya

Proceedings of the 7th IFESS Annual Conference　37-39　2002/06
A Method of Multichannel PID Control of 2-Degree of Freedom of Wrist Joint Movements by Functional Electrical Stimulation Peer-reviewed

Takashi WATANABE, Kan IIBUCHI, Kenji KUROSAWA, Nozomu HOSHIMIYA

The Transactions of the Institute of Electronics, Information and Communication Engineers　J85-D-II　(2)　319-328　2002/02
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0916-8532

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In restoration of paralyzed extremities by functional electrical stimulation (FES), stimulus intensity determination has an ill-posed problem because of redundancy of input-output relationship of the musculoskeletal system. We proposed a multi-inputs and -outputs PID controller and a parameter determination method of the controller. The controller was examined in controlling two-degree of freedom of wrist joint movements with neurologically intact subjects. Electrical stimulation was applied to four muscles through surface electrodes. The new method could provide a method of solving the ill-posed problem and was effective for multichannel closed-loop control of the wrist joint.
Development of a Closed-loop FES System Using 3-D Magnetic Position and Orientation Measurement System Peer-reviewed

Kenji Kurosawa, Takashi Watanabe, Ryoko Futami, Nozomu Hoshimiya, Yasunobu Handa

JOURNAL OF AUTOMATIC CONTROL　12　23-30　2002
Gradual potentiation of isometric muscle force during constant electrical stimulation Peer-reviewed

GM Eom, T Watanabe, N Hoshimiya, G Khang

MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING　40　(1)　137-143　2002/01
Publisher: PETER PEREGRINUS LTD
DOI： 10.1007/BF02347707 　

ISSN：0140-0118

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An investigation was carried out into how stimulation frequency and stimulation history affect the potentiation of muscle force during 20 s of constant stimulation of the two knee extensors in isometric conditions. Stimulation frequency significantly affected the potentiation pattern: low-frequency (2.5-10 Hz) stimulation showed a reduction and subsequent enhancement of force, and high-frequency (14.3-25 Hz) stimulation showed only enhancement of force. The degree of enhancement in force and time-to-peak decreased with the stimulation frequency. Whereas 40 Hz conditioning stimulation enhanced the muscle force, 14 Hz stimulation after 10 s of rest induced little force enhancement (8% in both muscles). When the frequency of the conditioning stimulation was 14 Hz and the main 14 Hz stimulation was applied after 50 s of rest, the initial force at the main stimulation was similar to the final force value of the conditioning stimulation (above 90% similarity). The potentiated twitch force slowly decayed during rest, with an average time constant of 2.4 min. These observations indicate that muscle potentiation depends on the stimulation frequency and stimulation history, and therefore a computer model of potentiation can play an important role in predicting muscle force and body movement induced by electrical stimulation.
A Basic Study of Utilizing the M-wave and Local Oxidative Metabolism of Muscle for an Estimation of Electrically Induced Muscle Force Peer-reviewed

Takashi Watanabe, Nozomu Hoshimiya

Japanese Journal of Medical Electronics and Biological Engineering　40　(2)　67-73　2002

DOI： 10.11239/jsmbe1963.40.67 　

ISSN：0021-3292

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This study focused on the estimation of muscle force developed by electrical stimulation to evaluate muscle fatigue during FES control. Muscle force, M-wave, and oxygenated hemoglobin and deoxygenated hemoglobin levels in a muscle were measured simultaneously under isometric conditions during electrical stimulation with three neurologically intact subjects. The oxygen consumption rate was estimated from the measured hemoglobin levels. Electrical current stimulation with 20Hz of frequency and 0.3ms of pulse width was applied to the right vastus lateralis muscle through surface electrodes. Stimulus pulse amplitude patterns were (a) long-term constant stimulation (increase for 10s and maximum for 590s) and (b) repetition of short-term constant stimulation (increase for 10s and maximum for 50s) with 10s interval (intermittent stimulation). The M-wave amplitude and the oxygen consumption rate were approximated to muscle force by the first-order linear equation, using the least-squares method. The results showed that the M-wave would be effective for muscle force estimation before severe muscle fatigue. The M-wave was also found to be useful in predicting muscle force decrease caused by muscle fatigue. As for the oxygen consumption rate, it was suggested that the rate would be useful for muscle force estimation during long-term stimulation, excluding the beginning of the stimulation. The reasons why the M-wave amplitude varied unstably when electrical stimulation was applied continuously more than 200 s and why the oxygen consumption rate was delayed from muscle force at the beginning of the first stimulation must be clarified. © 2002, Japanese Society for Medical and Biological Engineering. All rights reserved.
Detection of nerve action potentials under low signal-to-noise ratio condition Peer-reviewed

H Nakatani, T Watanabe, N Hoshimiya

IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING　48　(8)　845-849　2001/08
Publisher: IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI： 10.1109/10.936360 　

ISSN：0018-9294

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We propose a method for detection of action potentials (APs) under low signal-to-noise ratio condition. It is based on multiresolution analysis. Three parameters are used for detection. Two of them are for determining if there is an AP or not, and the other is for the estimation of waveforms. Our method provides better estimated waveforms than the conventional de-noising approach.
A Method for Solving ill-posed Problem in Multichannel Closed-loop FES Control Peer-reviewed

Takashi Watanabe, Kan Iibuchi, Kenji Kurosawa, Ryoko Futami, Nozomu Hoshimiya

Proceedings of the 6th IFESS Annual Conference　306-308　2001/06
Enhancement in muscle force during and after tetanic stimulation Peer-reviewed

GM Eom, T Watanabe, N Hoshimiya, G Khang, JH Yi, GR Tack

MEDICON 2001: PROCEEDINGS OF THE INTERNATIONAL FEDERATION FOR MEDICAL & BIOLOGICAL ENGINEERING, PTS 1 AND 2　677-679　2001
Publisher: UNIV ZAGREB

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The effects of muscle length on the enhancement of muscle force during electrical stimulation and the enhanced twitch muscle force behavior after tetanic stimulation were investigated. The degree of enhancement in developed muscle force and time-to-peak during 20Hz stimulation significantly decreased with the muscle length. The enhanced twitch force after conditioning stimulation slowly decayed with the average time constant of 2.38min. M-wave did not correlate with the post-tetanic twitch muscle force.
Recognition of lower limb movements by artificial neural network for restoring gait of hemiplegic patients by functional electrical stimulation Peer-reviewed

T Watanabe, S Yamagishi, H Murakami, N Furuse, N Hoshimiya, Y Handa

PROCEEDINGS OF THE 23RD ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOLS 1-4　23　1348-1351　2001
Publisher: IEEE
ISSN：1094-687X

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This study focused on man-machine interface of FES system for restoring gait of hemiplegic patients. A method of recognition of lower limb movements using an artificial neural network (ANN) was examined in monitoring restored motions and in giving control command with normal subjects and a hemiplegic patient. Acceleration signals were measured with a three-axis accelerometer attached to the heel of the normal side (right side) during walking for using in the recognition. Subjects performed some specific movements by their normal lower limbs supposing control command input in the walking measurements. The ANN recognized three different walking patterns, which were level floor walking, going up and down stairs, based on the acceleration waveforms with about 80% of recognition rate for normal subjects and above 70% for the patient. A similar structure of the ANN discriminated four specific movements by the lower extremity with more than 90% of recognition rate after the third performance of the movement simulated by using recognition and mis-recognition rates for experimentally measured data. The method was found to be useful in monitoring FES movements for safety and in giving control commands to the FES system without using upper limbs.
Classification of Nerve Action Potentials for Estimation of Sensory Unit Activity Peer-reviewed

Hironori Nakatani, Takashi Watanabe, Shigeo Ohba, Nozomu Hoshimiya

The Transactions of the Institute of Electronics, Information and Communication Engineers　J83-D-II　(12)　2841-2849　2000/12
The Possibility of Using M-waves Related to Double Pulses for Evaluating Muscle Fatigue in FES Control Peer-reviewed

T.Watanabe, N.Miura, N.Hoshimiya, Y.Handa

Japanese Journal of Medical Electronics and Biological Engineering　38　(1)　42-48　2000/03

DOI： 10.11239/jsmbe1963.38.42 　
Computer-aided generation of stimulation data and model identification for functional electrical stimulation (FES) control of lower extremities Peer-reviewed

G.Eom, T.Watanabe, R.Futami, N.Hoshimiya, Y.Handa

Frontiers of Medical and Biological Engineering　10　(3)　213-231　2000

DOI： 10.1163/15685570052062693 　
Analysis of a Normal Subject’s Standing-up for Comparison with Computer Generated FES Stimulation Data. Peer-reviewed

G.Eom, T.Watanabe, K.Kunugiyama, S.Ohba, R.Futami, N.Hoshimiya, Y.Handa

Proc. 21st Ann. Int. Conf. IEEE Eng. in Med. and Biol. Soc.　601　1999/10
Classification of action potentials recorded from peripheral nerves with cuff electrodes Peer-reviewed

H.Nakatani, T.Watanabe, S.Ohba, R.Futami, N.Hoshimiya, Y.Handa

Proc. 21st Ann. Int. Conf. IEEE Eng. in Med. and Biol. Soc.　484　1999/10
Automatic Classification of Nerve Action Potentials Recorded from Peripheral Nerves with Cuff Electrodes for a Closed-loop Functional Electrical Stimulation System Peer-reviewed

H.Nakatani, T.Watanabe, S.Ohba, R.Futami, N.Hoshimiya, Y.Handa

Proc. 4th Ann. Conf. Int. FES Soc.　85-88　1999/08
A Physiologically Based Non-linear Muscle Activation Model of Variable Stimulation Frequency Response Peer-reviewed

O.Gonzalo, T.Watanabe, R.Futami, N.Hoshimiya

Proc. 4th Ann. Conf. Int. FES Soc.　109-112　1999/08
Feedback FES Control Using Jacobian Matrix of the Musculoskeletal System: Experiments on the Wrist with Four Muscles of Normal Subjects Peer-reviewed

T.Watanabe, K.Iibuchi, R.Futami, N.Hoshimiya, Y.Handa

Proc. 4th Ann. Conf. Int. FES Soc.　295-298　1999/08
Control-command Detection for FES using Residual Specific Movement Peer-reviewed

N.Furuse, T.Watanabe, S.Ohba, R.Futami, N.Hoshimiya, Y.Handa

Proc. 4th Ann. Conf. Int. FES Soc.　319-322　1999/08
A Basic Study of Long-Term Force Potentiation during Constant Stimulation for Use in Prediction of FES-Induced Movement Peer-reviewed

G.Eom, T.Watanabe, R.Futami, N.Hoshimiya, Y.Handa

Proc. 4th Ann. Conf. Int. FES Soc.　323-326　1999/08
Control Command Input System Using Residual Motor Function for Motor Disabled Patients Peer-reviewed

N.Furuse, T.Watanabe, R.Futami, N.Hoshimiya, Y.Handa

Japanese Journal of Medical Electronics and Biological Engineering　37　(2)　152-160　1999/06
Publisher: None
DOI： 10.11239/jsmbe1963.37.152 　

ISSN：0021-3292
An approach to a muscle model with a stimulus frequency-force relationship for FES applications Peer-reviewed

T. Watanabe, R. Futami, N. Hoshimiya, Y. Handa

IEEE Transactions on Rehabilitation Engineering　7　(1)　12-18　1999/03
Publisher: IEEE
DOI： 10.1109/86.750545 　

ISSN：1063-6528

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A simplified model of electrically stimulated muscle for use in applications of functional electrical stimulation (FES) is discussed in this paper. The muscle model was required to have both stimulus frequency and stimulus intensity (amplitude/width) inputs. The stimulus frequency versus force relationship of rabbit muscle was modeled first with a small number of model parameters that could be identified by simple experiments in a short time. The model identified was found to be applicable to human muscles. The frequency-force relationships of electrically stimulated fast and slow type muscles were also predicted by the model. The frequency-force model and a simplified model of muscle activation dynamics were used to construct a muscle model that described the summation of muscle contraction. The use of this model decreased the time burden on patients during parameter identification at the clinical site. The clinical applicability of these new model descriptions was suggested through computer simulations.
A Possibility of Using M-waves Evoked by Double Pulses for Evaluating Muscle Fatigue on FES Control Peer-reviewed

Takashi Watanabe, Naoto Miura, Tatsufumi Kamimura, Shigeo Ohba, Ryoko Futami, Nozomu Hoshimiya, Yasunobu Handa

Proceedings of the 3rd Annual Conference of the International Functional Electrical Stimulation Society　CD-ROM　1998/09
A Basic Study on Computer Model and Stimulation Data Generation for FES Standing-Up Peer-reviewed

G.Eom, T.Watanabe, R.Futami, N.Hoshimiya, Y.Handa

Jpn. J. of Med. Electronics and Biol. Engng.　36　(1)　22-31　1998/03

DOI： 10.11239/jsmbe1963.36.22 　
Experimental tests of a musculoskeletal model of the elbow joint for FES applications Peer-reviewed

T Watanabe, T Nozawa, GM Eom, S Ohba, R Futami, N Hoshimiya, Y Handa

PROCEEDINGS OF THE 20TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOL 20, PTS 1-6　20　2594-2597　1998
Publisher: IEEE
ISSN：1094-687X

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Computer model prediction of motions developed by functional electrical stimulation (FES) can be effective for clinical applications. The musculoskeletal model that respond to electrical stimulation is necessary for the model prediction. In this paper, a musculoskeletal model of the elbow joint was tested experimentally on a normal subject with surface electrode stimulation. In the musculoskeletal model, the musculotendon guide that reflects geometrical arrangement of muscles was adopted. Parameters in the muscle model were adapted to the subject based on the force measured under the isometric condition. Output of the tuned model agreed well with experimental results of the single muscle stimulation at high amplitude of stimulation and results of the simultaneous antagonistic stimulation in some stimulus conditions.
Evaluation Method of Percutaneous FES Electrode after Implantation Peer-reviewed

S.Ohba, T.Watanabe, R.Futami, N.Hoshimiya, Y.Handa

Japanese Journal of Medical Electronics and Biological Engineering　35　(3)　320-324　1997/09

DOI： 10.11239/jsmbe1963.35.320 　
Fundamental Study on Creation of Stimulation Patterns with Artificial Neural Network for Functional Electrical Stimulation Peer-reviewed

H.Murakami, T.Machino, T.Watanabe, R.Futami, N.Hoshimiya, Y.Handa

Jpn. J. of Med. Electronics and Biol. Engng.　35　(4)　407-413　1997/09

DOI： 10.11239/jsmbe1963.35.407 　
Stimulus Frequency-Force Relation in Muscle Model for FES Applications Peer-reviewed

Takashi Watanabe, Tsuneyuki Nozawa, Gwang-Moon Eom, Shigeo Ohba, Ryoko Futami, Nozomu Hoshimiya, Yasunobu Handa

Proceedings of the Second Annual Conference of the International Functional Electrical Stimulation Society and Fifth Triennial Conference Neural Prostheses: Motor Systems 5　109-112　1997/08
A stimulus frequency-controlled muscle model for FES simulator Peer-reviewed

T Watanabe, S Ohba, R Futami, N Hoshimiya, Y Handa

PROCEEDINGS OF THE 18TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOL 18, PTS 1-5　18　551-552　1997
Publisher: IEEE

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The purpose of this study is to construct "FES simulator" which is a simulation system of restoring paralyzed motor functions with FES. The simulator enables to modify stimulation data through the estimation of motion by the data before applying the stimulation to a patient. In this paper, a practical model of electrically stimulated muscle was studied for FES simulator. Stimulus frequency-force characteristics obtained in our past work was used for describing the model with tractable parameters and for controlling the model by stimulus frequency with amplitude and/or width of a pulse. The description was useful to represent different properties between electrically stimulated fast and slow type muscles.
Evaluation of percutaneous electrode after implantation for FES Peer-reviewed

S Ohba, T Watanabe, R Futami, N Hoshimiya, Y Handa

PROCEEDINGS OF THE 18TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOL 18, PTS 1-5　18　333-334　1997
Publisher: IEEE

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A quantitative evaluation of implanted percutaneous electrodes for FES is required in clinical site. We measured impedance characteristics of the electrodes from outside of the body with the newly developed system. This measurement made it possible to estimate whether the implanted electrode is breaked or moved. In addition, it could also provide information about disconnection between the electrodes and the stimulator.
A basic study on computer model and stimulation data generation for FES Peer-reviewed

G Eom, T Watanabe, T Nozawa, S Ohba, R Futami, N Hoshimiya, Y Handa

PROCEEDINGS OF THE 19TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOL 19, PTS 1-6　19　1970-1973　1997
Publisher: IEEE
ISSN：1094-687X

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This study aims to develop a practical model of paralyzed patients for simulating FES-induced motions and methods of generating stimulation data for the desired motion. In this report, 'paraplegics' and 'standing up from a chair' are chosen as the first object patient and motion, respectively. Previous FES model studies of other groups often ignored the difficulty of estimating the model parameters, which made them impractical in clinical application. We made the musculoskeletal model easier to be clinically applied by simplifying it to include only the parameters that can be presently estimated noninvasively. Then we generated the stimulation data for standing up without arm-assistance, by manual adjustment and also by the dynamic optimization. Results showed that the present system with the practical model parameters is useful.
Development of Multi-Channel Implantable Functional Electrical Stimulation (FES) System for Clinical Usage Peer-reviewed

Nozomu Hoshimiya, Hiroki Higa, Takashi Watanabe, Hajime Murakami, Ryoko Futami, Hidetoshi Matsuki, Yasutaka Iguchi, Yasunobu Handa, Koro Takahashi, Takashi Furukawa, Yoshikazu Ogasawara, Takashi Shimotomai

Medical & Biological Engineering & Computing　34　(Supplement 1)　281-282　1996/06
Measurement of Stimulus Frequency-Force Characteristics for FES Control Method Including Differences between Fast and Slow Muscle Properties Peer-reviewed

T.Watanabe, K.Morita, H.Murakami, N.Hoshimiya, Y.Handa

Jpn. J. Med. Elect. Biomed. Engng　34　(1)　47-51　1996
Publisher: None
DOI： 10.11239/jsmbe1963.34.47 　

ISSN：0021-3292
A Study on Modification Method of Stimulation Patterns for FES Peer-reviewed

Kenji Kurosawa, Hajime Murakami, Takashi Watanabe, Ryoko Futami, Nozomu Hoshimiya, Yasunobu Handa

Jpn. J. Med. Elect. Biomed. Engng　34　(2)　103-110　1996
Publisher: None
DOI： 10.11239/jsmbe1963.34.103 　

ISSN：0021-3292
FES control of wrist joint angles based on the interpolation of stimulus-angle characteristics

T. Machino, H. Murakami, T. Watanabe, S. Ohba, R. Futami, N. Hoshimiya, Y. Handa

Proceedings of the 2nd International FES Symposium　174-180　1995/10
FES Simulator for Optimizing Control Method: Basic Concepts and A Preliminary Musculotendon Model

Takashi Watanabe, Hajime Murakami, Shigeo Ohba, Ryoko Futami, Nozomu Hoshimiya, Yasunobu Handa

Proceedings of the 2nd International FES Symposium　84-90　1995/10
Fail-Safe Circuits for Implantable FES System -Error Detecting and Correcting Circuits-

H. Higa, T. Watanabe, H. Murakami, S. Ohba, R. Futami, N. Hoshimiya, Y. Handa

Proceedings of the 2nd International FES Symposium　78-83　1995/10
A Basic Study on an FES Control Method Considering Fast and Slow Muscle Characteristics Peer-reviewed

K. Morita, T. Watanabe, H. Murakami, S. Ohba, R. Futami, N. Hoshimiya, Y. Handa

Proceedings of the 17th Annual International Conference of the IEEE Engineering in Medicine and Biology Society　CD-ROM　1995/09
Basic Study on Tongue Movement as a Control Command for Functional Electrical Stimulation (FES) System Peer-reviewed

Hajime Murakami, Kenji Morita, Takashi Watanabe, Nozomu Hoshimiya, Yasunobu Handa

Japanese journal of medical electronics and biological engineering　33　(4)　365-369　1995

DOI： 10.11239/jsmbe1963.33.365 　

ISSN：0021-3292

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Functional electrical stimulation (FES) has been developed in order to restore paralyzed motor functions of patients who have injured their upper motor neurons. Use of tongue movement was proposed as a control command for an FES system, because even quadriplegic patients can move their tongue voluntarily and generate much information easily. In this paper, we investigated the tongue movement by using a simple measurement system that simulated an input part of control commands in an FES system. The measurement system consisted of a 16-key membrane switch array, and a personal computer. The switch array detected the tongue movement as shift of touching area of the buccal region. We measured and discussed recognition rates by which the measurement system could recognize direction of tongue movement correctly. In this discussion, we assumed the following command-rules transverse and longitudinal direction were accepted as a command, and reentry was required if oblique direction or undetected condition occurred. Five healthy subjects operated the system by their tongue in experiments, and the recognition rates were calculated. The rates within three entries were more than 85% even by less-experienced subjects more than 95% by some subjects. The results of experiments during 5 days indicated that the repeatability of the recognition of the tongue movement was high. It implied that a precise calibration of a relative position between the system and a subject was not necessary. The results of this paper verified the fundamental feasibility of the use of tongue movement as a control command for an FES system. © 1995, Japanese Society for Medical and Biological Engineering. All rights reserved.
Basic Studies on Auricular Movement As a Control Command for Functional Electrical Stimulation (Fes) System Peer-reviewed

Hiroo Makari, Hajime Murakami, Takashi Watanabe, Nozomu Hoshimiya, Yasunobu Handa

Japanese Journal of Medical Electronics and Biological Engineering　32　(2)　121-128　1994

DOI： 10.11239/jsmbe1963.32.121 　

ISSN：0021-3292

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Functional electrical stimulation (FES) has been proposed as a technique that could restore the paralyzed motor functions of the patients who injured their upper motor neurons. in this paper, use of voluntary movement of the auricula was proposed as a control command for FES system. the movement may be used exclusively for controlling FES system, because it is seldom used in daily living. However, the percentage of persons who can move the auricula is small. in order to overcome this difficulty, a method of learning the movement was developed in this paper. the method was a training with electrical stimulation to the posterior auricular muscle and electromyogram (EMG) feedback. Three subjects attempted to learn the movement with this method, and two of them acquired the movement in a short term. Furthermore, in order to detect the auricular movement by EMG signal of the posterior auricular muscle, we studied the influenceof othermovements on the detection of the auricular movement. Power spectrum of noise during neck movement was distributed in lower frequency than that of the EMG signal. the noise during jaw movement was smaller in amplitude than the EMG signal. These experimental results suggested that the influence of both neck and jaw movements on detection of the auricular movement could be removed by appropriate signal processing. in addition, we also studied about fatigue characteristic of the posterior auricular muscle and reaction time of the auricular movement. It was difficult to move the auricula constantly over 1 minute, but it was probable to move it intermittently for 15 minutes. the reaction time of the movement was a little longer than that of finger movement. These suggested that the auricular movement could give short-time control commands repeatedly to FES system for long term. © 1994, Japanese Society for Medical and Biological Engineering. All rights reserved.
A BASIC STUDY ON SIMULTANEOUS STIMULATION TO THE ANTAGONISTIC MUSCLE PAIR BY FES - FORCE MEASUREMENT AT DIFFERENT MUSCLE LENGTHS Peer-reviewed

T WATANABE, H MURAKAMI, S OHBA, R FUTAMI, N HOSHIMIYA, Y HANDA

PROCEEDINGS OF THE 16TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY - ENGINEERING ADVANCES: NEW OPPORTUNITIES FOR BIOMEDICAL ENGINEERS, PTS 1&2　440-441　1994
Publisher: I E E E
Basic Study of the AuricuLar Movement as a Control Command for FES System -Learning Method of Voluntary Movement of the Auricula- Peer-reviewed

H. Makari, T. Watanabe, H. Murakami, S. Ohba, R. Futami, N. Hoshimiya, Y. Handa

Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Society　1270-1271　1993/10
Estimation of the Patellar Ligament Tension for FES Standing Peer-reviewed

N. Yamashita, K. Fujita, H. Murakami, T. Watanabe, S. Ohba, R. Futami, N. Hoshimiya, Y. Handa, M. Ichie

Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Society　1338-1339　1993/10
Fundamental Study on the Restoration of the Body Movement by Functional Electrical Stimulation (FES) -Part 3 : EMG Measurement for Elemental and Combined Motions of the Body- Peer-reviewed

Yukinori Matsushita, Hajime Murakami, Takashi Watanabe, Shigeo Ohba, Ryoko Futami, Nozomu Hoshimiya, Yasunobu Handa

Proceedings of the 15th Annual International Conference of the IEEE Engineering in Medicine and Biology Society　1340-1341　1993/10
RESPONSE OF THE ANTAGONISTIC MUSCLE PAIR BY SIMULTANEOUS STIMULATION

T. Watanabe, H. Murakami, S. Ohba, R. Futami, N. Hoshimiya, Y. Handa

Proceedings of the 1st International FES Symposium　30-35　1992/07
Basic Study of Peripheral Nerve Stimulation with Cuff Electrodes Part 3: Electrical Stimulation with a Slowly-rising Semi-rectangular Pulse

T. Yasui, T. Watanabe, H. Murakami, S. Ohba, R. Futami, N. Hoshimiya, H. Takahashi, Y. Handa

Proceedings of the 1st International FES Symposium　58-63　1992/07
RESPONSE OF THE NEUROMUSCULAR SYSTEM BY SIMULTANEOUS STIMULATION TO THE ANTAGONISTIC MUSCLE PAIR Peer-reviewed

N HOSHIMIYA, T WATANABE, H MURAKAMI, S OHBA, R FUTAMI, Y HANDA

PROCEEDINGS OF THE ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY, VOL 14, PTS 1-7　14　1469-1470　1992
Publisher: I E E E
Variable Polarizer by Liquid Crystal-Doped Bulk Plastics with Distributed Rotatory Power Peer-reviewed

Hiroki Yamamoto, Takashi Watanabe, Shinzo Muto, Hiroshi Ito

電子情報通信学会論文誌　J72-C-I　(6)　361-364　1989/06
Publisher: None
ISSN：0915-1893

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Misc. 79

A Basic Study of Application of a Portable Gait Rehabilitation System to Walking of Hemiplegic Subjects in Daily Living

116　(312)　35-38　2016/11/18
Publisher: 電子情報通信学会
ISSN：0913-5685
A Basic Study on Measurement of Knee Joint Angle Using Inertial Sensors During Free Gait in Daily Living

116　(312)　29-34　2016/11/18
Publisher: 電子情報通信学会
ISSN：0913-5685
FESによる麻痺肢の運動制御とそのリハビリテーション応用に向けて

渡邉高志

電気学会誌　136　(10)　670-673　2016/10
Publisher: The Institute of Electrical Engineers of Japan
DOI： 10.1541/ieejjournal.136.670 　

ISSN：1340-5551
A Study on Stimulation Start Timing based on EMG Signals for FES Cycling with Cycling Wheelchair

115　(317)　1-4　2015/11/20
Publisher: 電子情報通信学会
ISSN：0913-5685
A Basic Study on Effect of Rehabilitation Using Cycling Wheelchair with FES with a Hemiplegic Subject

KARASAWA Yuta, SHIOTANI Maho, Tadano Takumi, WATANABE Takashi, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　114　(514)　85-88　2015/03/16
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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Rehabilitation system using a cycling wheelchair with FES has been studied by our research group. However the effect of rehabilitation of FES cycling with the cycling wheelchair has not been clear. In this report, the effect of rehabilitation of cycling using cycling wheelchair was examined with a hemiplegic subject. Ankle dorsiflexion angle during walking increased after voluntary cycling. However the muscle fatigue influenced the movement of ankle dorsiflexion after FES cycling. It is necessary to perform more experiments eliminating method fatigue in order to make clear the effect of rehabilitation of FES cycling.
A basic study on analyzing acceleration of crank rotation for evaluation of FES cycling with cycling wheelchair

Yuta Karasawa, Takashi Watanabe, Yasunobu Handa

Transactions of Japanese Society for Medical and Biological Engineering　52　27-O-28　2014/08/17
Publisher: Japan Soc. of Med. Electronics and Biol. Engineering
DOI： 10.11239/jsmbe.52.O-27 　

ISSN：1347-443X 1881-4379

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The cycling wheelchair “Profhand” was developed as a transportation device for hemiplegic persons. The cycling wheelchair is also expected to be used by paraplegic patients as a rehabilitation device with functional electrical stimulation (FES). We have been studying the FES cycling system using the cycling wheelchair for paraplegic patients. However, cycling speed of FES cycling was less than that of voluntary cycling. The purpose of this study was to evaluate FES cycling. In this paper, acceleration of crank rotation was estimated as an index relating to rotative force during FES cycling with 2 healthy subjects in order to evaluate cycling speed. The result showed the points that reduced the cycling speed were estimated. It is expected to improve the FES control system by finding out the reason of the decreasing of acceleration. It is also necessary to make clear relation between acceleration of crank rotation and rotative force.
A basic study on estimation of foot dorsiflexion movement during walking from measurement in sitting position for FES-assisted foot drop correction

Maho Shiotani, Takashi Watanabe, Shun Endo, Katsunori Murakami, Yoshimi Kumagai, Naomi Kuge

Transactions of Japanese Society for Medical and Biological Engineering　52　25-O-26　2014/08/17
Publisher: Japan Soc. of Med. Electronics and Biol. Engineering
DOI： 10.11239/jsmbe.52.O-25 　

ISSN：1347-443X 1881-4379

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Functional electrical stimulation (FES) is effective to correct foot drop. Although electrode position and stimulation intensity to develop appropriate dorsiflexion are determined in sitting position, FES movement during walking may differ from that in sitting position. That is, it is better to determine appropriate electrode position and stimulation parameters by estimating foot movement during walking from measurement in sitting position. In this report, ankle dorsiflexion angle during FES-assisted walking and that developed by electrical stimulation in sitting position were measured on two hemiplegic subjects with inertial sensors. In both subjects, there were some trials that dorsiflexion angle at 95% of gait cycle was different from that in sitting position. In some trials of one subject, effect of drop foot correction decreased during gait. Decrease of dorsiflexion angle may cause falling, thus it is necessary to study reason of decrease of effect of foot drop correction.
A Study on Measurement of Lower Limb Angles with Inertial Sensors : Evaluation with Healthy Subjects in Normal Gait and Circumduction Gait

TERUYAMA Yuta, WATANABE Takashi

IEICE technical report. ME and bio cybernetics　113　(499)　19-24　2014/03/17
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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In our research group, a measurement system of lower limb angles was developed using inertial sensors. The developed system calculated angles based on integration of the angular velocity component of the one axis corresponding to the movement. The angle measurement method showed practical measurement accuracy in measurement of lower limb angles during walking of healthy subjects. However, measurement accuracy of 3 dimensional movements such as circumduction gait of hemiplegic patients has not been studied. In this paper, an angle measurement method based on quaternion, in which three axes components of angular velocity were used, was introduced to realize practical measurement of movements of gait with stable measurement accuracy. Measurement of normal and circummaduction gaits of healthy subjects using inertial sensors and 3D motion analysis system showed effectiveness of the quaternion based method for 3D gait measurement in comparison to the conventional method based on integral of angular velocity.
A Study of Stimulation Timing based on Cycling Velocity for FES-Cycling Wheelchair

MURAKAMI Takuya, OHASHI Kento, WATANABE Takashi, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　112　(479)　65-68　2013/03/13
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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This study aimed at developing cycling wheelchair rehabilitation system using FES, which is compact and easy to use at clinical site. We developed a simple FES control system that did not need extensive modification of the wheelchair using a wireless inertial sensor and wireless electrical stimulators and appropriate muscles for FES cycling were found. However, cycling speeds of FES cycling were slower and less stable than voluntary cycling. In this report, a method of determination of stimulation timing considering the cycling speed and the muscle reaction time was proposed and tested. It was shown that the cycling speed was raised and became stable.
A Study on Measurement of 3D Movements of Lower Limbs with Inertial Sensors : Evaluation with Rigid Body Models

OHASHI Kento, WATANABE Takashi

IEICE technical report. ME and bio cybernetics　112　(479)　69-74　2013/03/13
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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In our previous studies, a measurement system of lower limb movements was developed using inertial sensors. The sensor system calculated lower limb angles based on integral of angular velocity. The angle measurement method was evaluated in measurement of angles in the sagittal plane during gait of healthy subjects. However, a measurement method of 3D movements including large angle change in the frontal plane has not been developed and evaluated. In this paper, a measurement method of 3D movements using quaternion was developed and evaluated in measurement of 2D and 3D movements of rigid body models. 2D movements were measured with good accuracy using the previous method based on the integral of angular velocity and the new method using quaternion. It was showed that 3D movements could be measured with reasonable accuracy using both methods, although, measurement of 3D movements showed larger error than measurement of 2D movements with both methods.
A Study on Improvement of Measurement Accuracy of Kalman-filtering-based Angle Measurement Method Using Inertial Sensors

TERUYAMA Yuta, WATANABE Takashi

IEICE technical report. ME and bio cybernetics　112　(297)　11-16　2012/11/09
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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In this study, development of wearable sensor system using inertial sensors has been focused with the aim of rehabilitation support. For measurement of joint angles with this system, kalman-filtering-based angle measurement method was developed and was shown to have practical accuracy. However, there was a problem that the error was increased due to movement acceleration. In this report, the method of previous research that adjusts parameter values of kalman filter based on the values of acceleration was tested. A newly proposed method that adjusts the parameter values based on the difference between the estimated angle by kalman filter and the angle calculated from accelerometers was also tested. From the result of experiment using a rigid body model, it was suggested that the proposed method could improve measurement accuracy than the method of acceleration-based parameter adjustment.
無線型ウェアラブルセンサによる運動リハビリテーション・ヘルスケア支援～実用的な歩行計測・評価システムの実現に向けて～

渡邉高志

電波技術協会報FORN　287　38-41　2012/07
Functional Electrical Stimulation (FES) Control for Restoration and Rehabilitation of Motor Function

Takashi Watanabe, Naoto Miura

Technological Advances in Biomedicine for Healthcare Applications　80-93　2012
Publisher: IGI Global
A Basic Study on Kalman-filtering-based Angle Measurement Method in Measurement with Different Inertial Sensors

TERUYAMA Yuta, WATANABE Takashi, ENDO Shun

111　(314)　19-23　2011/11/17
703 Analysis of dynamic foot movement by electrical stimulation on gastrocnemius muscles

SUZUKI Tatsuto, WATANABE Takashi, SAURA Ryuichi, UCHIYAMA Hironobu

85th　(85)　7.3-3"　2010/03/16
Publisher: The Japan Society of Mechanical Engineers
Cyborg technology and gait assistance - A possibility of functional electrical stimulation (FES)-

Takashi Watanabe

Journal of the Society of Instrument and Control Engineering　47　(12)　1045-1050　2008/12
Publisher: 計測自動制御学会
ISSN：0453-4662
An Error Reduction Method of Portable, Low-Cost Joint Angle Sensor System for Human Movement Measurement and Control

ARIFIN Achmad, SAITO Hiroki, WATANABE Takashi

IEICE technical report　108　(314)　31-34　2008/11/14
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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We tested two methods of error reduction of gyroscope in measuring knee joint angle during cyclic movements. The first method was using two gyroscopes and a Kalman filter to reduce the error. In the second method, a Kalman filter was designed to estimate true joint angle by utilizing additional information from two tilt sensors. The second method reduced the error significantly. The sensor fusion with the Kalman filter would be applicable for sensing human movements in clinical measurement system or for clinical FES control.
圧電式ジャイロスコープを用いた足底接地期の検出に関する基礎的検討 (第29回バイオメカニズム学術講演会 SOBIM2008 予稿集) -- (身体運動の解析)

峯岸由佳, 渡邉高志, 古瀬則夫

バイオメカニズム学術講演会予稿集　29　19-22　2008/10/25
Publisher: バイオメカニズム学会
A basic study on an application of center of mass information for sit-to-stand balance control (第29回バイオメカニズム学術講演会 SOBIM2008 予稿集) -- (身体運動の解析)

Cabra Oscar David Pena, 渡邉高志, 吉澤誠

バイオメカニズム学術講演会予稿集　29　23-26　2008/10/25
Publisher: バイオメカニズム学会
1C1-1 Assistive Technology by Using Functional Electrical Stimulation for Motor Disabled Patients : Problems and Expectations for Practical Clinical Use

Watanabe Takashi

The JSME Symposium on Welfare Engineering　2008　31-34　2008/09/17
Publisher: The Japan Society of Mechanical Engineers

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Functional electrical stimulation (FES), which uses electric current or voltage pulses applying to peripheral nerves or muscles, is a method of restoring or assisting motor functions lost by spinal cord injury or cerebrovascular disease. Although FES can be applied to various functions, FES studies have been heading mainly for restoring or assisting motor function focusing on upper or lower limb control. Many studies on clinical application of FES in controlling upper or lower limbs have found that FES can be effective. However, FES system for practical clinical use has not been realized yet. In this paper, problems on clinical application of FES are discussed, first. Then, our current research topics especially focused on control method of paralyzed motor functions of upper and lower limbs are presented.
片麻痺者の歩行遊脚期のCycle-to-Cycle制御に基づくFES制御法の開発 : 制御器パラメータ調整器の検討(3.2 第6回情報シナジー研究会, 3. 研究活動報告)

加茂井敏晃, 渡邉高志, Arifin Achmad, 吉澤誠

年報　7　100-103　2008/07
Publisher: 東北大学サイバーサイエンスセンター
Fundamental Study on a Power Supply System for FES Gait Restoration of Hemiplegic Patients

MURAKAMI Hajime, KOBAYASHI Hiroaki, ITOH Ken-ichi, WATANABE Takashi, OHBA Shigeo, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　101　(611)　55-60　2008/02/25
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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A new Functional Electrical Stimulation (FES) system which electric power is generated by users themselves is proposed for the gait restoration of hemiplegic patients by controlling their drop foot. Specifications for the system are clarified and a prototype system for 1-channel stimulation with surface electrodes is developed. Its function is experimentally evaluated, and the dorsiflexion of the ankle joint of a normal subject is elicited by using the system. Hence the fundamental feasibility of the method is verified.
A Study on FES Control for the Swing Phase of Hemiplegic Gait based on cycle-to-cycle Control : Model Simulation under the Condition of Varying Initial Joint Angles

KAMOI Toshiaki, WATANABE Takashi, ARIFIN Achmad, YOSHIZAWA Makoto

IEICE technical report　107　(351)　17-20　2007/11/15
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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The purpose of this study is to develop fuzzy controller based on the cycle-to-cycle control for controlling the swing phase of gait by using functional electrical stimulation (FES). In our previous computer simulation study, initial joint angles at the beginning of the swing phase and parameters of subject model were fixed. In this report, the fuzzy controller was tested in computer simulation with several different subject models, in which the initial joint angles were varied for each cycle at random. Results suggested that the controller could develop the swing phase when the angle between the foot and floor was not varied. However, early foot contact to the floor was caused occasionally. This has to be studied in more detail.
A Study of Effect of ISM on FES Control Using Feedback Error Learning : Computer Simulation of 2-DOF Movement Control of the Wrist Joint

WATANABE Takashi, SUGI Yoshihiro, KUROSAWA Kenji, YOSHIZAWA Makoto

IEICE technical report　107　(248)　5-8　2007/10/04
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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An application of the Feedback Error Learning (FEL) to Functional Electrical Stimulation (FES) control was examined through computer simulation. The previously developed FEL-FES controller, which used an inverse dynamics model (IDM) as a feedforward controller, frequently could not learn appropriately characteristics of the control object in the case of controlling 2-DOF movements of the wrist stimulating 4 muscles. In this paper, an inverse statics model (ISM) that was trained with data obtained by simple measurements was used with the IDM for the feedforward controller. Computer simulation tests showed that the ISM would be useful in FES control and in IDM training. Since there were some cases that successful learning of the IDM was not achieved, those cases have to be examined in more detail for clinical use of the FEL.
6項システム制御研究会(3節工学研究会,第5章国際会議・シンポジウム等)

吉澤誠, 渡邉高志

東北大学電気通信研究所研究活動報告　14　297-297　2007/01/01
Measurement of Hip, Knee and Ankle Joint Angles during Walking by using Piezoelectric Gyroscopes

FURUSE Norio, WATANABE Takashi

IEICE technical report　106　(370)　49-52　2006/11/15
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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The joint angles of the lower limb are important parameters in evaluating the ability and stability of the walking in walking training or FES gait control. In this study, the effectiveness of a measurement method of hip, knee and ankle joint angles that used gyroscopes attached to the trunk, the thigh, the shank and the foot was examined in the measurement of the leg joint angles during walking with three neurologically intact subjects. The results showed a low difference and a high correlation between the joint angles measured with the commercially available electric goniometer and those with the gyroscopes. The examined measurement method of the lower limb joint angles was expected to be used effectively in the walking training or FES gait restoration at clinical site.
片麻痺者の歩行遊脚期のcycle-to-cycle制御に基づくFES制御法--筋電図に基づく刺激データの検討 (第27回バイオメカニズム学術講演会 SOBIM 2006 予稿集) -- (義肢・FES)

渡邊高志, 柴田聡, Arifin Achmad

バイオメカニズム学術講演会予稿集　27　167-170　2006/10/28
Publisher: バイオメカニズム学会
FES Control Method of the Swing Phase of Hemiplegic Gait based on Cycle-to-Cycle Control : Model Simulation Study on Stimulation Data for using Surface Electrode

WATANABE Takashi, SHIBATA Satoshi, ARIFIN Achmad, YOSHIZAWA Makoto, HOSHIMIYA Nozomu

IEICE technical report　106　(330)　25-28　2006/10/20
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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We proposed a fuzzy controller based on the cycle-to-cycle control for controlling the swing phase of hemiplegic gait by using functional electrical stimulation (FES). The controller was found to be effective in the previous computer simulation studies. However, surface electrode stimulation could not be used because a deep muscle was included for the control. In this study, the control method was modified, in which control target of the rectus femoris was changed to the hip joint angle and stimulation to the hamstrings was added at the beginning of the swing. Computer simulation showed that the control method could be applied using surface electrode.
6項システム制御研究会(3節工学研究会,第5章国際会議・シンポジウム等)

吉澤誠, 渡邉高志

東北大学電気通信研究所研究活動報告　12　273-273　2006/08/01
上肢FES制御の計算機シミュレーションツールの開発(3.2 第4回情報シナジー研究会, 3. 研究活動)

杉義宏, 渡邉高志, 吉澤誠

年報　5　84-87　2006/06
Publisher: 東北大学情報シナジーセンター
Fundamental study on selective control command input system by using laser devices for handicapped

MURAKAMI Hajime, ITO Fumiaki, EGAWA Takashi, WATANABE Takashi, HOSHIMIYA Nozomu

IEICE technical report　106　(80)　21-24　2006/05/19
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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We studied a selective control command input system for the handicapped. A user of the system selects one of the photo-detectors on a desk by using a laser pointer on his/her head. Each detector corresponds to a command of a device for the handicapped, e.g. Functional Electrical Stimulation system. A signal from the detector is compared to the baseline that is a signal measured without laser light. If one of the detected signals is much greater than the baseline, the system recognizes that the detector receives the laser light. Therefore, the user can select a control command by using the laser light. We verified the feasibility of the system that recognized the selected photo-detector, even if the background light varied.
6項システム制御研究会(3節工学研究会,第5章国際会議・シンポジウム等)

吉澤誠, 渡邉高志

東北大学電気通信研究所研究活動報告　13　280-280　2006/01/01
A Study of the FES Control on the 2-DOF Wrist Joint's Movement Using Feedback Error Learning

CHOSA Seiichi, WATANABE Takashi, YOSHIZAWA Makoto, HOSHIMIYA Nozomu

IEICE technical report　105　(402)　13-16　2005/11/17
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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Although the feasibility of FES controller using feedback error learning was shown in our previous study, control error was large in the early stage of training. A new way of applying FEL to FES control was proposed in this study and it was found to be effective through computer simulation. Then, computer simulation study showed that multichannel FES controller using the new FEL application was feasible on controlling the 2-DOF wrist joint's movement.
経皮的電気刺激による皮膚感覚を用いたパターン提示に関する基礎的検討 (第26回バイオメカニズム学術講演会(SOBIM2005 in Tochigi)予稿集) -- (感覚と脳)

佐藤由規, 渡邉高志, 吉澤誠

バイオメカニズム学術講演会予稿集　26　275-278　2005/10/22
Publisher: バイオメカニズム学会
機能的電気刺激(FES)による歩行制御法の開発のための筋骨格モデルの構築 (第26回バイオメカニズム学術講演会(SOBIM2005 in Tochigi)予稿集) -- (シミュレーションとモデル解析)

柴田聡, 渡邉高志, Arifin Achmad

バイオメカニズム学術講演会予稿集　26　183-186　2005/10/22
Publisher: バイオメカニズム学会
21. 人工神経回路(ANN)による動作認識を用いた運動機能障害者のための制御命令入力システムに関する基礎的検討(平成16年度東北支部大会抄録, 支部大会抄録)

藤原大樹, 渡辺高志, 村上肇, 古瀬則夫, 吉澤誠, 星宮望

生体医工学 : 日本エム・イー学会誌　43　(2)　330-330　2005/06/10
Publisher: 日本生体医工学会
ISSN：1347-443X
A test of fuzzy controller of cycle-to-cycle control for controlling three-joint movements of swing phase of FES gait

25　43-46　2004/10/23
Publisher: バイオメカニズム学会
FESによる運動機能代行－現在の方法と課題，制御技術の開発－

渡邉高志, 星宮望

日本エム・イー学会雑誌BME　18　(4)　3-10　2004/10
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe1987.18.4_3 　

ISSN：0913-7556
機能的電気刺激(FES)での利用を目的とした上肢筋骨格モデルシミュレーション(3.2 第2回情報シナジー研究会, 3. 研究活動)

渡邉高志, 大塚雅幸, 吉澤誠

年報　3　101-105　2004/06
Publisher: 東北大学情報シナジーセンター
Design of Fuzzy Controllers for Cycle-to-Cycle Control of Swing Phase of FES-induced Hemiplegic Gait

24　199-202　2003/10/04
Publisher: バイオメカニズム学会
運動麻痺の機能再建のための機能的電気刺激（FES）技術

渡邉高志, 星宮望

最新医学　58　(6月増刊)　1496-1506　2003/06
21.PIDパラメータ切替え型閉ループFES制御に関する基礎的検討(平成14年度東北支部大会抄録)

大塚雅幸, 渡辺高志, 黒沢健至, 星宮望

生体医工学 : 日本エム・イー学会誌　41　(1)　68-68　2003/03/10
Publisher: 社団法人日本生体医工学会
ISSN：1347-443X
23.A Test of Fuzzy Controller for Cycle-to-Cycle Control of FES-induced Hemiplegic Gait : Computer Simulation in Single-joint Control

Arifin A., Watanabe T., Hoshimiya N.

Transactions of the Japanese Society for Medical and Biological Engineering : BME　41　(1)　68-68　2003/03/10
Publisher: Japanese Society for Medical and Biological Engineering
ISSN：1347-443X
22.片麻痺者での手関節2自由度運動の閉ループFES制御の検討(平成14年度東北支部大会抄録)

松平哲郎, 渡辺高志, 黒沢健至, 星宮望, 半田康延

生体医工学 : 日本エム・イー学会誌　41　(1)　68-68　2003/03/10
Publisher: 社団法人日本生体医工学会
ISSN：1347-443X
Cycle-to-Cycle Control of Swing Phase of FES-induced Hemiplegic Gait : A Computer Simulation with Different Controllers

ARIFIN Achmad, WATANABE Takashi, HOSHIMIYA Nozomu

IEICE technical report. ME and bio cybernetics　102　(481)　1-4　2002/11/21
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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This study focused on controlling FES-induced gait using cycle-to-cycle control. Stimulation burst duration was regulated to control the maximum knee-joint and ankle-joint angles of a current cycle based on the errors of the previous cycles. This control method was implemented on a fuzzy controller and a PID controller. An adaptive PID controller and an adaptive fuzzy controller implemented the method too. All of control schemes were tested in swing phase control by computer simulation using a musculo-skeletal model. The fuzzy controller had faster response than the PID controller in compensating muscle fatigue. Online adaptation of controller parameters in the adaptive PID and the adaptive fuzzy controllers had no significant effect on improving control response.
Cycle-to-Cycle制御による片麻痺者の閉ループFES歩行のための目標値の決定

渡辺高志, Arifin Achmad, 星宮望

バイオメカニズム学術講演会予稿集　23　133-136　2002/10/26
Publisher: バイオメカニズム学会
リハビリテーション工学におけるITの必要性 : 機能的電気刺激(FES)を例にして(2.<特集>第1回情報シナジー研究会)

渡邉高志, 吉澤誠, 東北大学情報シナジーセンター先端情報技術研究部, 東北大学情報シナジーセンター先端情報技術研究部

年報　2　43-47　2002/07/01

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我々はこれまで、運動機能障害に対するリハビリテーションの分野で、機能的電気刺激(FES)による麻癖肢の動作再建に関する工学的研究を行ってきた。FESは、臨床的に有効性が示されてきたが、麻痒の症状や電気刺激の効果に関する患者ごとの違いや多様性に対応していくためには、多くの課題が残されている。本稿では、FESによる麻痺肢の動作再建における問題点を工学的観点からいくつか挙げて、情報技術(IT)を応用することによる解決の可能性について考えた。
シナジー効果による教育研究のイノベーション : 先端情報技術研究部が目指すもの(2.<特集>第1回情報シナジー研究会)

吉澤誠, 渡邉高志, 東北大学情報シナジーセンター先端情報技術研究部, 東北大学情報シナジーセンター先端情報技術研究部

年報　2　25-30　2002/07/01

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先端情報技術研究部の役割は、「シナジー効果による教育研究のイノベーション」であり、最先端情報技術の応用研究、情報技術基盤の高度利用技術の開発推進、教育・研究現場の情報化のための最適な情報技術の利用支援、および上記研究を遂行する人材の育成である。本講演では、現在推進している研究の一端と、将来における本研究部のあるべき姿について示す。
A Basic Study of Utilizing the M-wave and Local Oxidative Metabolism of Muscle for an Estimation of Electrically Induced Muscle Force

WATANABE Takashi, HOSHIMIYA Nozomu

Transactions of Japanese Society for Medical and Biological Engineering　40　(2)　67-73　2002/06/10
Publisher: 日本エム・イー学会
ISSN：1347-443X
A Study of Muscle Fatigue Evaluation on Electrical Stimulation Using M-waves Related to Stimulation Including Double Pulses

KONNO Shunsuke, WATANABE Takashi, NAKATANI Hironori, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　101　(733)　31-36　2002/03/11
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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Early occurrence of muscle fatigue is one of problems on FES. We have studied muscle fatigue evaluation using M-waves related to stimulation including double pulses. The stimulation experiment using double pulses with different inter pulse interval (IPI) suggested M-wave evoked by double pulse with short IPI reflected activity of fast type muscle fiber. M-waves evoked by double pulses stimulation with different IPI had a possibility of evaluating progress of muscle fatigue. The long time stimulation experiment suggested value of parameters of M-waves, which related to conduction velocity (CV), changed earlier than muscle force decrease. Therefore, parameters related to CV can be used for early diagnosis of muscle fatigue. We showed that the M-waves evoked by double pulses provided useful estimation of muscle force than M-waves evoked by single pulse.
A Study of Detecting Target Information for Arbitrary Hand Reaching Restoration by FES

ANZAI Akihiro, WATANABE Takashi, MURAKAMI Hajime, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　101　(733)　25-30　2002/03/11
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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In order to develop the FFS system that restores arbitrary hand reaching, it is necessary to detect three-dimensional position of the target object and to identify shape of the object. In this paper, we made a detection system of target information, which consisted of a magnetometric 3-D position sensor and a laser pointer. We evaluated accuracy of detecting positions and height of target objects. We also studied a method of discriminating shapes of objects that could be obstacles or targets of grasping. Experimental results suggested that the system could detect objects' position and height, and discriminate shape of objects, so as to use the detection system with FES system.
Development of a Closed-loop FES System using a 3-D Position and Orientation Sensor

KUROSAWA Kenji, YOSHIZAKI Fumitaka, WATANABE Takashi, FUTAMI Ryoko, HOSHIMIYA Nozomu

16　369-372　2001/08/29
Functional Electrical Stimulation for Independence of Elderly Person

渡辺高志, 星宮望

Journal of the Society of Instrument and Control Engineering　40　(5)　373-378　2001/05
Publisher: The Society of Instrument and Control Engineers
DOI： 10.11499/sicejl1962.40.373 　

ISSN：0453-4662
A study on multichannel feedback FES control of the wrist joint

IIBUCHI K., WATANABE T., KUROSAWA K., OHBA S., FUTAMI R., HOSHIMIYA N., HANDA Y.

IEICE technical report. ME and bio cybernetics　100　(478)　117-124　2000/11/23
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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The commercially available functional electrical stimulation(FES)system in Japan uses EMG-based stimulation data for determining stimulus intensities. This method can solve the ill-posed problem caused by the redundancy in the input-output relationship of the musculoskeletal system. However, this open-loop control is affected by muscle fatigue, disturbance and so on. On the other hand, the closed-loop control is effective in removing those problems, although it is difficult to determine stimulus intensities to each muscle because of the ill-posed problem. In this study, we used the generalized inverse of the Jacobian matrix of the musculoskeletal system and the CHR(Chien, Hrones and Reswick)method in order to determine parameters of the PID controller. The experimental results with normal subjects showed that the proposed feedback controller could control the wrist joint angles with good performance in tracking taska.
A Study on Movement Recognition for FES Gait Control of Hemiplegic Patients

YAMAGISHI Shiho, WATANABE Takashi, FURUSE Norio, MURAKAMI Hajime, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　100　(478)　109-116　2000/11/23
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685

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In order to develop a user-friendly Functional Electrical Stimulation (FES)system with high level of safety, we studied man-machine interface of the FES system considering reconstruction of gait of hemiplegics. First, recognition of different walking patterns(straight on the level floor, upstairs and downstairs)was studied using an artificial neural network(ANN)based on acceleration waveforms measured during the walking with six normal subjects. We found that the ANN could recognize each walking pattern in real time. This method will be useful in monitoring FES movement for safety. We also found that a similar structure of the ANN could recognize specific movements of the lower limb from acceleration patterns. This technique can be applied to detecting control commands to the FES system without using the upper limb.
Estimation of Isometric Muscle Torque during Constant Stimulation for Evaluating Muscle Fatigue in FES

WATANABE Takashi, KAMIMURA Tatsufumi, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

15　69-72　2000/10/13
A Study on Estimation of Muscle Fatigue using Measurement of Local Oxidative Metabolism and M - Wave during Electrical Stimulation

KAMIMURA T., WATANABE T., OHBA S., FUTAMI R., HOSHIMIYA N., HANDA Y.

IEICE technical report. ME and bio cybernetics　99　(458)　69-76　1999/11/19
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685
A Basic Study on Recognition of Different Walking Patterns for FES Gait Restoration of Hemiplegic Patients

YAMAGISHI Shiho, WATANABE Takashi, FURUSE Norio, MURAKAMI Hajime, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　99　(458)　77-84　1999/11/19
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685
Integral control method for calculating a memory address of Functional Electrical Stimulation (FES) system

MURAKAMI H, NISHIMURA N, MASUDA R, ITOH K, WATANABE T, HOSHIMIYA N, AKASAKA K, HANDA Y

IEICE technical report. ME and bio cybernetics　99　(458)　85-90　1999/11/19
Publisher: The Institute of Electronics, Information and Communication Engineers
ISSN：0913-5685
A Study on Estimation of Muscle Fatigue using Measurement of Local Oxidative Metabolism and M-Wave for FES Control

KAMIMURA T., WATANABE T., OHBA S., FUTAMI R., HOSHIMIYA N., HANDA Y.

14　169-172　1999/10/06
失われた神経機能の回復：機能的電気刺激

星宮望, 嚴光文, 渡邉高志

日本ME学会雑誌BME　13　(8)　11-17　1999/08
Publisher: Japanese Society for Medical and Biological Engineering
DOI： 10.11239/jsmbe1987.13.8_11 　

ISSN：0913-7556
A study on multiunit neural recordings with cuff electrodes and classification of nerve action potentials based on multivariate analysis

NAKATANI Hironori, WATANABE Takashi, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　98　(672)　9-16　1999/03/19
Publisher: The Institute of Electronics, Information and Communication Engineers

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In order to extract information from peripheral nerves, recordings of neura] activities were made with cuff electrodes and the nerve action potentials were classified into unit activities. Aetion potentials. wcre classified based on their wavefonns, as recorded waveforms were affected by the radius of nerve fiber and the distance between fiber and recording electrode. Por objective classification, hierarchical cluster analysis and the criterion based on variance ratio were used. The result was quite reasonable, so the class ification method proposed in this study might he applicable to automatic classification of ncrve action potentials.
A Basic Study on Development of FES System for Restoring Arbitrary Reaching

ARINO Keiko, WATANABE Takashi, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　98　(671)　83-90　1999/03/18
Publisher: The Institute of Electronics, Information and Communication Engineers

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Since reconstruction of the upper extremity movement by FES has been done by using stimulation patterns derived from EMG analysis with normal subjects, the variation of movements developed by FES has been limited. In order to make FES system more practical in clinical applications, we proposed the user interface and the method of calculating wrist trajectory to construct an FES system for reaching movement between two arbitrary points for C_4 tetraplegia. We developed a user interface using head movements for the input of the target position of reaching. We also investigaied the method of making wrist trajectory of the reaching based on analysis of normal subject's reaching movements. Initial and final points of the trajectory detected by the sensor system were used to determine the wrist trajectory.
A Basic Study on Stabilizing the Sensation elicited by Electrocutaneous Stimulation

WATANABE Shun-ichi, WATANABE Takashi, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　98　(400)　33-40　1998/11/17
Publisher: The Institute of Electronics, Information and Communication Engineers

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In studies of sensory feedback to patients paralyzed by spinal cord injury or cerebrovascular diseases, electrical stimulation to the skin through surface electrodes(electrocutaneous stimulation)is widely used. The purpose of this study is to stabilize sensations elicited by electrocutaneous stimulation. First, unstable contact of stimulation electrode with the skin, which causes pain sensation, was studied through measurement of skin impedance using two types of electrodes. Then, to make clear the cause of the variation of electrocutaneous sensation threshold(absolute threshold)with time and difference of the threshold between locations of electrodes, variations of the absolute threshold and skin impedance with time were measured at various electrode locations. It was suggested that the skin impedance was related to the absolute threshold of electrocutaneous stimulation.
A Study on a Creation Method of Stimulus Patterns for Controlling Upper Extremities with Hybrid FES

FURUSE Norio, WATANABE Takashi, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　97　(622)　75-82　1998/03/20
Publisher: The Institute of Electronics, Information and Communication Engineers

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Functional Electrical Stimulation(FES) is widely used for restoring movements of paralyzed upper extremities. When it is applied to restoration of shoulder movements that have high degree of freedom, the number of stimulus electrode is increased and control of movement is difficult. In order to solve this problem, we proposed Hybrid FES which restores elbow function with FES and shoulder one with an active(motorized) orthosis. Analysis of electromyogram(EMG) obtained from normal subjects can be an effective method of creating stimulus patterns for FES. Interpolation of measured EMG signals was adopted into a creation method of stimulus patterns for Hybrid FES. Hence we measured EMG signals during voluntary elbow flexion with shoulder posture maintained by the orthosis, and interpolated the signals for creating stimulus patterns. Then, usefulness of the interpolated pattern in restoring movements by means of the Hybrid FES was investigated. We also studied influence of movement velocity on the EMG signals, and discussed range of movement velocity restored.
A Study on Head Movement as Control Commands of Welfare Apparatus for Seriously Paralyzed Persons

FURUSE Norio, WATANABE Takashi, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　97　(371)　113-120　1997/11/07
Publisher: The Institute of Electronics, Information and Communication Engineers

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When seriously paralyzed persons (e.g., spinal cord injury patients) use a welfare apparatus, they have to control it with their residual motor functions. Two types of operations which consist of selection and confirmation are necessary for command input to the apparatus. In this study, a 3D position measurement device put on the head was used for control commands detection. The nodding was recognized by the artificial neural network connected with the device. The recognized nodding was used as the command for the confirmation. Then, in order to study command input apparatus using head movements, we constructed the character input apparatus which uses the confirmation together with the selection. The selection was made by the cervical flexion, extension, rotation and other head movements. We examined the performance of the command input apparatub in character-input and sentence-input with four normal subjects. The results suggested that the input apparatus was useful.
A study on Musculotendon-skeleton Combination Model at the Elbow Joint for FES Simulator

NOZAWA T., WATANABE T., EOM G., OHBA S., FUTAMI R., HOSHIMIYA N., HANDA Y.

IEICE technical report. ME and bio cybernetics　97　(371)　121-128　1997/11/07
Publisher: The Institute of Electronics, Information and Communication Engineers

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Sendai FES Research Project uses stimulus data based on EMG signals from normals to restore paralyzed motor functions by FES. However, Adjustment of stimulus data is required for each muscle. The goal of our study is to develop the FES simulator which can estimate motions of patients during electrical stimulation. The FES simulator will make it possible to get adequate data for each patient without many times of trial and error modification of the data with the patient. This study aims to make musculoskeletal model for estimating whole body motion developed by FES. For this purpose, it is important to consider the geometry of bones and the fact that musclotendons are surrounded by ohter tissues. In this report, by introducing musculotendon guide, simulation results showed agreements approximatery with experimental results.
A study on estimation of sensory information from peripheral nerve trunk

NAKATANI Hironori, WATANABE Takashi, OHBA Shigeo, FUTAMI Ryoko, HASHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　97　(371)　43-50　1997/11/07
Publisher: The Institute of Electronics, Information and Communication Engineers

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Recordings of peripheral nerve activities were made with cuff electrodes to extract sensory information. To record sensory-unit activities is necessary to get sensory information from nerves but it is very difficult to record each activity separately, because the unit activity is recorded from the outside of nerve trunk. It is considered amplitude and the shape of the recorded action potential from a sensory-unit depends on the axonal diameter and the distance between the axon and the recording electrodes. Multivariate analysis was used to decompose the time series of action potential into the activity of each sensory unit based on amplitude and waveform of action potential. Activity of each sensory unit was observed when different stimulation was applied.
EMG measurement of an upper extremity as a control signal for Functional Electrical Stimulation (FES) system

MURAKAMI H, ITOH K, WATANABE T, HOSHIMIYA N, AKASAKA K, HANDA Y

IEICE technical report. ME and bio cybernetics　97　(371)　129-134　1997/11/07
Publisher: The Institute of Electronics, Information and Communication Engineers

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For restoration of motor function of upper extremity of hemiplegic patients, we have proposed "EMG-controlled FES system" which measures voluntary EMG signals as a control command and stimulates paralyzed muscles. In order to realize a bi-lateral movement, a user manipulates a hand while he/she generates an EMG signal for the control of the other hand. In this paper, we performed an experiment with a normal subject. The joint angle of the wrist and the EMG signal from the dorsi-flexor were measured during tracking tasks, and the error between the measured and the target signal was analyzed. From the results, the fundamental feasibility of the system was verified.
A study on the extraction of sensory information from nerve action potentials

NAKATANI H., WATANABE T., OHBA S., FUTAMI R., HOSHIMIYA N., HANDA Y.

12　389-392　1997/09/04
Musculotendon-skeleton Combination Model for FES Simulator : A study on antagonistic muscle pair at the elbow joint

NOZAWA T., WATANABE T., EOM G., OHBA S., FUTAMI R., HOSHIMIYA N., HANDA Y.

12　377-380　1997/09/04
A Basic Study on Modulation Method of FES for Preventing Urinary Incontinence

NISHIZAWA Masaki, WATANABE Takashi, NAMIMA Takashige, UCHI Keiichiro, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu, ORIKASA Seiichi

IEICE technical report. ME and bio cybernetics　96　(581)　91-98　1997/03/17
Publisher: The Institute of Electronics, Information and Communication Engineers

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A functional electrical stimulerion (FES) system has been developed for restoring motor functions of paralyzed extremities, and this system is also effecive for preventing urinary incontinence. The purpose of this study is to investigate stimulation methods for high urethral closing pressure in short time, and for long time low closing pressure of the urethra, respectively.
A Study on Creation Method of Stimulation Pattern for Restoration of Upper Extremity Movements by Hybrid Functional Electrical Stimulation

FURUSE Norio, MURAKAMI Hajime, WATANABE Takashi, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　95　(596)　67-72　1996/03/18
Publisher: The Institute of Electronics, Information and Communication Engineers

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Functionial Electrical Stimulation (FES) is widely used for restoring movements of paralyzed upper extremities. When it is used for the movement that requires large joint torque (e.g., the shoulder movement), the fatigue of stimulated muscles sometimes becomes a problem for clinical application. In order to solve this problem, we propose FES combined with an active (motorized) orthosis. The analysis of electromyogram (EMG) obtained from normal subjects is an effective method of creating standard stimulation patterns for FES. Hence we measured EMG signals during voluntary elbow movements with shoulder movements simultaneously moved by an active orthosis, and interpolated the signals for creating stimulation patterns. From the results, we investigated that the interpolated pattern is useful for restoring the movements by means of the FES with the active orthosis. We also considered influence of using the active orthosis on the upper extremity movements.
機能的電気刺激（FES）技術の運動機能障害者支援への応用

渡辺高志, 星宮望

エル・エス・ティ学会誌　7　(3)　3-9　1995/09
Publisher: THE SOCIETY OF LIFE SUPPORT ENGINEERING
DOI： 10.5136/lifesupport1986.7.3_3 　

ISSN：0912-1595
A Basic Study on FES Control Including Differences between Fast and Slow Muscle Properties

WATANABE Takashi, MORITA Kenji, MURAKAMI Hajime, OHBA Shigeo, FUTAMI Ryoko, HOSHIMIYA Nozomu, HANDA Yasunobu

IEICE technical report. ME and bio cybernetics　95　(84)　101-108　1995/05/26
Publisher: The Institute of Electronics, Information and Communication Engineers

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A portable multi-channel functional electrical stimulation (FES) system has been developed in order to restore motor functions of paralyzed extremities. In the present clinical FES system, muscle contraction is controlled by amplitude or pulse width modulation of stimulus pulse trains with constant stimulus frequency. The purposes of this study are to form an FES control method having capability of dealing with different muscle properties and to improve control ability of the FES system. As the FES control method considering muscle property and having improved control ability, amplitude modulation with pulse frequency modulation is studied. In this paper, the difference between fast and slow muscle responses at various stimulus frequencies was investigated with rabbits. A few ideas of FES control methods considering these properties were discussed.
機能的電気刺激（FES）による運動機能障害者の支援

渡辺高志, 星宮望

障害者の福祉　14　(6)　5-7　1994/06
重度の運動機能麻痺、電気刺激で機能回復

渡辺高志, 星宮望

ＢＣＬ　67　8-11　1994/04
A Study on Dynamics of Self-similar Neural Network Model

Watanabe Takashi, Murakami Hajime, Ohba Shigeo, Futami Ryoko, Hoshimiya Nozomu, Handa Yasunobu

IEICE technical report. ME and bio cybernetics　94　89-96　1994
Publisher: The Institute of Electronics, Information and Communication Engineers

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Functional Electrical Stimulation(FES)using stimulation patterns made from electromyogram(EMG)of normal subject is effective method on restoring paralyzed motor functions.This method contains simultaneous antagonistic control of voluntary movement. Simultaneous antagonistic stimulation method,which is to stimulate the antagonist with the agonist simultaneously,produces a good effect on the restoration,since it improves steep response of electrically stimulated muscle.Further study about the simultaneous stimnulation is necessary for better control of neuromuscular system by FES.Purposes of this study are to quantify and to make clear mechanism of the effect.In this paper,the effect of simultaneous antagonistic stimulation was evaluated quantitatively,and relation between the effect and the spinal reflex system was discussed.
Basic Study on Measurement of Tongue Motions as a Control Command Source for Functional Electrical Stimulation (FES) System

Morita Kenji, Murakami Hajime, Watanabe Takashi, Ohba Shigeo, Futami Ryoko, Hoshimiya Nozomu, Handa Yasunobu

IEICE technical report. ME and bio cybernetics　93　69/75　1993
Publisher: The Institute of Electronics, Information and Communication Engineers

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A control command source for FES system used by high-level quadriplegic patients needs to be independent of ADL (Activities of Daily Living) of the user and be operated easily.The purpose of this study is to evaluate the transcutenous measurement of tongue motions as a control command source.An experimental system consists of a latticed membrane switches.It detects the tongue motion which is performed vertically , first position.More command signals can be obtained by combination of these motions.It was confirmed by experiments on normal subjects that tongue motions can be used as a control command source for FES system,and above system is effective for measuring tongue motions.

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Presentations 20

Measurement and Control of Lower Limb Movements for Gait Rehabilitation of Hemiplegic Subjects International-presentation

5th International Conference on Bioinformatics and Biomedical Technology　2013/03/17
運動麻痺者を支援する機能的電気刺激(FES) ～生体に学ぶ動作の制御～

電子情報通信学会アンテナ・伝播研究会　2008/10/16
Detection of Gait Phases with Piezoelectric Gyroscope under Different Walking Speed Conditions International-presentation

Norio Furuse

13th Annual Conference of the International Functional Electrical Stimulation Society　2008/09
A Preliminary Test of Modified Applying Methods of Feedback Error Learning for FES Control International-presentation

13th Annual Conference of the International Functional Electrical Stimulation Society　2008/09
Application of Knowledge Engineering and Fuzzy System in Realizing Cycle-to-Cycle Control Method for Swing Phase of FES-induced Gait International-presentation

A. Arifin, T. Masuko

3rd International Symposium on Medical, Bio- and Nano-Electronics　2008/03
Functional Electrical Stimulation (FES) for Motor Disabled Patients International-presentation

3rd International Symposium on Medical, Bio- and Nano-Electronics　2008/03
Basic Experiments of Physiological Properties for Information Presenting Method Using Dynamic Electro-cutaneous Sensation Patterns International-presentation

6th International Conference on Bioelectromagnetism (ICBEM07)　2007/10
An Experimental Test of Fuzzy Controller Based on Cycle-to-Cycle Control for FES-induced Gait: Knee Joint Control with Neurologically Intact Subjects International-presentation

11th Mediterranean Conference on Medical and Biological Engineering and Computing (the MEDICON 2007)　2007/06
A Study on Sensing System of Lower Limb Condition with Piezoelectric Gyroscopes: Measurements of Joint Angles and Gait Phases International-presentation

11th Mediterranean Conference on Medical and Biological Engineering and Computing (the MEDICON 2007)　2007/06
Gait Re-education System for Incomplete Spinal Cord Injured Patients -Measurement of Hip Joint Angle by Piezoelectric Gyroscope- International-presentation

11th Annual Conference of the International Functional Electrical Stimulation Society　2006/08
A basic study on upper limb control by FES using feedback error learning with IDM and ISM International-presentation

11th Annual Conference of the International Functional Electrical Stimulation Society　2006/08
A Basic Study of Fuzzy Controller for Cycle-to-Cycle Control of Knee Joint Movements of FES Swing: First Experimental test with a Normal Subject International-presentation

11th Annual Conference of the International Functional Electrical Stimulation Society　2006/08
A test of multichannel closed-loop FES control on the wrist joint of a hemiplegic patient International-presentation

10th Annual Conference of the International FES Society　2005/07
A Computer Simulation Study of the Feedback Error Learning Controller for FES on the Wrist Joint's 1-DOF Movement International-presentation

6th Asian-Pacific Conference on Medical and Biological Engineering (APCBME 2005)　2005/04
A Test of Stimulation Schedule for the Cycle-to-Cycle Control of Three-joint Movements of Swing Phase of FES-induced Hemiplegic Gait International-presentation

6th Asian-Pacific Conference on Medical and Biological Engineering (APCBME 2005)　2005/04
COMPUTER SIMULATION FOR MULTICHANNEL CLOSED-LOOP FES CONTROL OF THE WRIST JOINT International-presentation

8th Vienna International Workshop on Functional Electrical Stimulation　2004/09
Gait Re-education System for Incomplete Spinal Cord Injured Patients - Measurement of Leg Joint Angles by Piezoelectric Gyroscope - International-presentation

9th Annual Conference of the International Functional Electrical Stimulation Society　2004/09
AN APPROACH TO REAL-TIME PARAMETER DETERMINATION OF THE MULTICHANNEL CLOSED-LOOP FES CONTROLLER International-presentation

IEEE EMBS Asian-Pacific Conference on Biomedical Engineering 2003　2003/10
Feedback Error Learning for Controlling 1-DOF Joint Angle: Model Simulation and Experiment International-presentation

8th Ann. Conf. Int. FES Soc.　2003/07
Gait Re-education System for Incomplete Spinal Cord Injured Patients - Development of Gait Measurement System - International-presentation

8th Ann. Conf. Int. FES Soc.　2003/07

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Industrial Property Rights 1

筋の活動度又は疲労度の評価装置

Property Type: Patent

Research Projects 29

Studies on Man-Machine Interface for Motor Disabled Patients Competitive

1994/04 - Present
Study on Control of Neuromuscular System by Functional Electrical Stimulation(FES) Competitive

1990/04 - Present
バーチャルリアリティ技術を活用した3次元環境での視覚認知障害者の自立支援手法研究

田中敏明, 飯島勝矢, 藪謙一郎, 大月敏雄, 三浦貴大, 渡邉高志, 白銀暁

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(B)

Institution: 東京大学

2023/04/01 - 2026/03/31
高齢者の身体機能に対応する持続支援可能なロボット型パーソナルモビリティの研究開発

田中敏明, 加藤士雄, 小舘尚文, 三浦貴大, 渡邉高志, 白銀暁

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 挑戦的研究(開拓)

Institution: 東京大学

2020/07/30 - 2023/03/31

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2021年度（2022年5月）の課題である高齢者の関節運動と正常な関節運動との誤差を経時的にモニタリングする．また，RPM（ロボットスーツとパーソナルモビリティ）自体もセンシングし，高齢者の動きとの連動性を監視するシステムを構築する．結果として、ヒトとRPMの関節運動をセンシングするIMUを用いた歩行分析システムを構築した。歩行アプリとスマホを用いた無線式となった。健常人で歩行分析を実施した結果、データのバラツキを検討する変動係数において10％以下という再現性のあるデータの取得が可能となった。また、課題の一つである感覚フィードバックシステム構築として、歩行アプリで使用した無線式センサを用いて体幹および上下肢運動で異常運動を起こした際に，センサが感知し，振動と音声による複合刺激を使用者（患者）に提示するシステムを構築した。これにより、無線式位置センサで下肢関節の運動を監視し，正常運動から逸脱する場合，振動および音声刺激で注意を促すことが可能となった．また，RPM側自体にも位置センサを使用し，ヒトの動きを支援しつつ，異常運動を生じないよう監視可能となった。加えて、既製品である歩行アシストロボットを用いて、ロボットの関節運動とそれを装着したヒト側の関節運動が一致しているか動作解析装置を用いて計測分析した。結果として、ロボットスーツとヒトの関節位置のズレは膝関節、足関節ともに数センチとなった。また、運動制御が軽度であるほど、ズレは大となった。この結果より、ズレが歩行時のどのタイミングで大となり、使用する高齢者、障害者に負担と危険を伴うか詳細に検討可能なIMUセンサと注意喚起システムの構築の必要性が示唆された。
半側空間無視者の空間動作支援のための注意喚起機能付き視覚バリアフリー機器開発研究

田中敏明, 飯島勝矢, 加藤士雄, 泉隆, 巖淵守, 三浦貴大, 渡邉高志

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 基盤研究(B)

Institution: 東京大学

2020/04/01 - 2023/03/31

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本研究は、申請者が開発した3次元視覚情報呈示装置としてHMD（ヘッドマウントディスプレイ）を用い，これに動的な歩行・ADL動作時支援のための動作のセンシングを無線同期し，かつ，経時的に無視領域へ注意喚起を促すため視覚・聴覚・体性振動感覚による複合感覚フィードバック装置と眼球計測装置を搭載し、遠隔での使用を可能とする空間動作支援のための感覚フィードバックを利用した注意喚起機能付き視覚バリアフリー機器開発研究を実施する． 2021年度は、①本HMDシステムに必要な聴覚，振動によるフィードバックシステムを製作し、かつ、動的条件である日常生活活動に応用可能とするため特に歩行を支援可能とするHMDシステムを構築することを目標とした。結果として、HMDと歩行計測を同期するなかで、視覚認知障害者への注意喚起として、関節運動計測用IMUセンサと振動装置を組み合わせることに成功し、かつ、音声（聴覚刺激）による注意喚起を加えるシステムとした。健常人5名、脳卒中患者1名においては、本フィードバックシステムは振動、聴覚の複合感覚刺激がより注意を促せる結果となった。しかしながら、振動刺激が歩行速度が速い場合、認知しにくい場面もあり、この点を補ううえでHMD上での視覚提示と音声刺激をさらに改良する必要がある。②加えて、HMD使用時の脳機能活動を分析として近赤外分光法（NIRS: nearinfrared spectroscopy）を用いて、HMDを用いた半側空間無視検査時の脳の賦活領域を計測分析した。結果として、脳卒中患者2名の無視障害の局在側と考えられる前頭葉で脳の賦活が健常側と異なり低下していることを明らかとした。
Sensing the Signs of Fall Occurrence in the Elderly

Watanabe Takashi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Research (Exploratory)

Institution: Tohoku University

2019/06/28 - 2022/03/31

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Based on the idea of detecting signs of falls from gait changes, a method for detecting gait change using a neural network was developed. The results showing the feasibility of classifying gait pattern and classifying factors that cause gait change by using unsupervised learning were also obtained. Then, in order to estimate values of indices of factors that cause gait changes related to falls, methods to detect and evaluate abnormal foot movements in the early stance phase during walking, to estimate automatically stride length and walking speed, to detect automatically gait event timings, and to estimate the body center of mass position for evaluating balance during walking were developed using inertial sensors. Furthermore, a correlation between total sleep time and the feeling of walking instability in healthy subjects was found, which suggested the possibility of using total sleep time in detecting signs of falls.
Estimation of center of mass trajectory of the body during 3D movements based on inertial sensor signals

Watanabe Takashi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2016/04/01 - 2019/03/31

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This study aimed to developing a method to estimate movement trajectory of the center of mass (CoM) position of the body in 3D movements using inertial sensors. First, sensor attachment positions of the trunk and the thigh segments were examined, from which the upper part of the trunk and the lateral side of the thigh were determined to attach inertial sensors. Then, the calculation methods of the foot position and the segment vector of each part of the body were examined. Based on the results, the method of estimating the CoM position based on reconstructing the posture using the body link model was constructed using the foot position and the segment vectors. Finally, the constructed CoM trajectory estimation method was examined experimentally, and factors of the estimation error were discussed. The results showed that the anteroposterior and vertical components of the CoM position were useful, and the applicability to evaluation of movements of the CoM trajectory was suggested.
Development of at-home lower limb rehabilitation system based on teaching support to induce active movements

Watanabe Takashi, HANDA yasunobu, SEKI kazunori, FURUSE norio, SHIBASAKI jun, KUGE naomi, MURAKAMI katsunori

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2015/04/01 - 2019/03/31

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This study aimed to realize a home rehabilitation system focusing on motor dysfunction in the lower limbs. First, methods of calculating evaluation indexes of lower limb motor function from inertial sensor signals were developed. Then, an electrical stimulation teaching method to induce active movements for rehabilitation was constructed and its effectiveness was examined in foot drop correction during walking. The stimulation timing of the teaching in pedaling wheelchair rehabilitation was also determined. In addition, in order to assist movements in rehabilitation, methods of assisting foot movements during walking and propulsion of the pedaling wheelchair were developed by using functional electrical stimulation (FES). Finally, a portable system applied to home rehabilitation was developed. Motion measurement and evaluation methods using a few inertial sensors were also proposed for home rehabilitation and shown to be useful in experimental tests.
New development and application of estimation methods of joint torque and generated power using inertial sensors during movements

Watanabe Takashi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2014/04/01 - 2016/03/31

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A method of estimating lower limb joint torques by using inertial sensors without ground reaction force and 3D motion measurement system were examined for squat and sit-to-stand movements in the sagittal plane. The method estimated lower limb joint torques by using segment inclination angles measured with inertial sensors and an assumption of no external force to the top segment. The proposed estimation method was shown to be feasible from results of comparison of estimated joint torques to those estimated by ground reaction force and data from 3D motion measurement system. An estimation method of the number of strokes and push cycle during wheelchair propulsion using an inertial sensor attached on the upper arm was shown to be useful. Timings of hand contact on pushrim and hand release from it was suggested to be possible with inertial sensors. An estimation method of generated power in wheelchair propulsion by users were examined and problems to be solved were confirmed.
Development of motion capture system using wireless inertial sensors and its test in application to rehabilitation

WATANABE TAKASHI

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Challenging Exploratory Research

Institution: Tohoku University

2012/04/01 - 2014/03/31

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A prototype system of motion capture system using wireless inertial sensors was developed. Three dimensional motion measurement method was also developed and tested with the developed prototype system. Measurements of gait with healthy and motor disabled subjects showed that the developed system and the motion measurement method were useful. Furthermore, the developed system and the measurement method were modified based on problems found in the measurement tests. It was expected that the system would be applied practically to rehabilitation.
Development and validation of active control type FES rehabilitation system with muscle fatigue monitor

WATANABE Takashi, FURUSE Norio, SEKI Kazunori, FURUSE Norio

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2010 - 2012

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A prototype FES rehabilitation system was developed and shown to be useful for gait rehabilitation of hemiplegic subjects, in which FES was used to assist in producing voluntary dorsiflexion. Muscle fatigue evaluation index using amplitudes of M-waves elicited by various additional stimulation pulses was proposed and shown to be feasible to apply to repetitive movement training using short time electrical stimulation. It was shown that FES rehabilitation system with muscle fatigue monitor would be realized by implementing the developed techniques.
Sit-to-stand rehabilitation device with electrical stimulation and reduction of body weight to improve walking performance

SUZUKI Tatsuto, WATANABE Takashi, UCHIYAMA Hironobu, SAURA Ryuichi, ISHIDA Kyoko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: Maizuru National College of Technology

2009 - 2012

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上記の英訳 This study is aimed at developing a sit-to-stand rehabilitation device with electrical stimulation and reduction of body weight to improve walking performance. This study discussed following three important points. (1) Develop a link model for sit-to-stand motion and find the possible sit-to-stand area. And find the standard sit-to-stand motion from the experiments with the participants in various ages. (2) Develop an assist-as-needed control strategy and validate it in the case of propelling an attendant-propelled wheelchair, and develop the posture evaluation system by wearable IMU sensors. (3) Develop the electrical stimulation methodology in rectus femoris and gluteal muscles, and evaluation the subjective pain by electrical stimulation.
Development and application of walking training system to progressed gait patients

FURUSE Norio, WATANABE Takashi, MITO Kazuyuki

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: Miyagi National College of Technology

2008 - 2010

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The sensor system that was able to carry small as possible to be installed in the body easily was developed, and because the walking training device developed in the present study assumed use with home, the improvement was added and used for the device that assumed the assistive device and the training area places such as the canes and walkers. The sensor system etc. that completed it were installed in the body and the walking experiment by the able-bodied person was developed, and whether data was able to be acquired by the doing sensor was confirmed, the data was used in addition, useful training information for those who trained was presented, and the wavy processing system that was able to present the achievement level of the walking training was developed.
小型センサによる運動機能評価に関する研究 Competitive

System: The Other Research Programs

2009/04 -
Cooperative residual movement control in restoration of paralyzed limbs by functional electrical stimulation(FES)

WATANABE Takashi, FURUSE Norio

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2006 - 2008
Development of an injectable and implantable microstimulator for neuromodulation and neuromuscular control

HANDA Yasunobu, MATSUKI Hidetoshi, SATO Humihiro, SEKI Kazunori, OGURA Takahide, WATANABE Takashi, TAKAHASHI Takayuki, HUTRAMI Ryoko, KANOU Shinnichiro

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (S)

Institution: Tohoku University

2004 - 2008
Development of Sensor System for Walking Training of Incomplete Spinal Cord Injured Patients

FURUSE Norio, WATANABE Takashi

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: Miyagi National College of Technology

2006 - 2007

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It is a purpose of this study to develop the sensor system that automatically evaluates the coverage of training and presents information profitable for the gait improvement to the paralysis person is developed. Therefore, the methods of the waveform processing to the sensor that measures the leg state during the patients walking training were examined. In the sensor system, wireless communication was used to transmit the output signal from the sensor module etc. to the main system and the personal computer. The system that improved a clinical utility was able to be constructed without wiring from the sensor to use the wireless communication. Development of the wireless module was performed by the joint development with Izumi Tec Ltd. It is considered that a small and inexpensive gyroscope is useful to construct a practical sensor system in clinical. In this study, we examined the simultaneous measurement method of the lower limb joint angles and the gait phases by using the gyroscopes. From the result of the walking analysis with normal subjects, it was indicated that the sensor system could measure the joint angles with sufficient accuracy and could detect practicably the swing phase and the stance phase without mistake. Therefore, the sensing system of lower limb condition with appropriate accuracy that could be used in clinical would be constructed compactly at inexpensive by using the gyroscopes.
Cycle-to-Cycle制御によるFES歩行再建手法の開発

渡邉高志

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 若手研究(B)

Institution: 東北大学

2003 - 2004

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実用的で有効性の高いCycle-to-Cycle制御による閉ループFES歩行制御手法を開発するための研究を行い,本年度は以下の成果を得た. (1)筋骨格モデルを,股関節も制御可能にするように改良し,さらに,両側下肢の運動を表現できるようにして,片麻痺者を想定したモデルシミュレーションを実行可能にした.これにより,片麻痺者の健側を健常者の歩行動作計測から得た関節角度軌跡をもとに動作させながら,遊脚期のFES制御を検討することが,計算機シミュレーションで可能になった. (2)上記の改良した筋骨格モデルを用いた計算機シミュレーションにより,cycle-to-cycle制御による歩行の遊脚期のFES制御を,ファジー制御器を用いることで比較的容易に実現できることを示した.また,cycle-to-cycle制御で必要となる各筋への刺激タイミング表の設計指針を計算機シミュレーションで検討した.健常者の歩行中の筋電図(EMG)のパターンだけではFES制御は困難であり,筋の機能や筋骨格系の運動学的な知見を反映させて刺激タイミング表を作成することが有効であることを示した. (3)製作したプログラマブル電気刺激装置について,ポータブル化を考慮して新しく設計した刺激回路による電気刺激の効果を試験した.運動発現のための刺激効果は十分であったが,パルス振幅の安定性と,刺激データやセンサ計測データの通信速度の改善が必要であったことから,刺激装置内のマイクロコントローラのプログラム等を修正し,実用的に使用できるように改善した. (4)ジャイロを用いた簡便な下肢関節角度の計測センサの製作,下肢運動制御実験用器具の設計・製作を行い,上記の刺激装置とあわせて,下肢FES制御の実験システムを構築した.健常者での基礎実験を通して,実験システムの評価を行い,充分機能することを確認した.
Measurement and analysis of biosignals for FES control of paralyzed patient

HOSHIMIYA Nozomu, FUTAMI Ryoko, WATANABE Takashi, KANOH Shin'ichiro, NAKATANI Hironori, HANDA Yasunobu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2001 - 2003

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For developing the flexible human-computer interface systems for controlling the Functional Electrical Stimulation (FES) system, the measurement and analysis of biosignals were investigated as follows. 1.Measurement and categorization of nervous action potential For use of the information included in action potential acquired from peripheral nerves as the input to the FES stimulator, the following techniques were established. (1)high accuracy measurement of action potentials using cuff electrodes placed on the nerve bundle. (2)algorisms of information extraction of sensory events from measured action potential sequences 2.Man-machine interface based in EEG and EOG High S/N EEG and EOG measurement method and the information extraction methods from measured EEG and EOG data were investigated to develop the man-machine interface for FES system. 3.For the development of flexible FES system, the methods to acquire FES control commands (feedback information) from the biosignals using sensors were investigated.
Stabilization of cutaneous sensation elicited by electric stimulation and its application to sensory feedback

FUTAMI Ryoko, KANOH Shinichiro, WATANABE Takashi, HOSHIMIYA Nozomu, HANDA Yasunobu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

2000 - 2002

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The relationship between absolute threshold and the parameters of an electrical equivalent circuit for skin impedance was examined with neurologically intact subjects. The equivalent circuit consisted of resistance Rp and capacitance Cp connected in parallel, plus resistance Rs in series to both. As a result, for Ag-AgCl electrodes with electroconductive paste, variationsover time of the frequency characteristics of Rp and Cp were found to be similar to the changes caused by repeatedly stripping the skin. Values of Cp and Rp at 10Hz were found to relate to the absolute threshold with high correlation coefficients. Next we estimated the parameters of the equivalent circuit by measuring stimulus pulse current abd viltage waves of square-wave pulses using solid-gel electrodes. The absolute threshold increased with repeated electrical stimulation to the skin and decreased after adequate rest with no electrical stimulation. Rp decreased with repeated electrical stimulation and increased after rest, while Cp did not change. A significant correlation between Rp and the absolute threshold was observed. These results show that electrical stimulation to the stratum corneum affects both absolute threshold and skin impedance; they also indicate that real-time evaluation is important for stabilizing cutaneuos sensation elicited by electrical stimulation. Possible reasons for decreasing Rp were an increase of ionic conductivity due to osmosis of electroconductive paste into the stratum corneum due to charge transfer. The increase of the threshold amplitude was considered to be the result of broadened current pad due to increases if ionic or electric conductivities in the stratum corneum. It is necessary to clarify the mechanism of those relationsship between threshold and impedance parameters.
冗長性を有する筋・骨格系のフィードバックFES制御に関する基礎研究

渡邉高志

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 奨励研究(A)

Institution: 東北大学

2000 - 2001

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機能的電気刺激(FES)による筋・骨格系の制御においては,電気刺激時の筋・骨格系の入出力関係(刺激強度-関節角度特性)に冗長性があり,刺激強度の決定が不良設定問題になることが多い.本研究では,そのような系のフィードバック制御を実現するための検討を行い,今年度は以下の成果を得た. 1.手関節の2自由度運動に加え,前腕の回内外,肘関節の屈曲・伸展を計測可能にするために,磁気式の3次元位置角度センサを用いて計測システムを構築した.この計測システムを用いてフィードバック制御を行うために,パルスモジュレータを製作し,プログラムの改良を行った.健常被験者での表面電気刺激による制御実験で,これまでの電気角度計を用いたシステムと同様の制御結果が得られることを確認し,フィードバック制御システムの拡張に成功した. 2.改良したシステムを用いて,片麻痺患者1名で,健常被験者で行ってきた実験と同様に,手関節2自由度運動の表面電極による4筋刺激によるフィードバック制御実験を行った.電気刺激に対する筋の応答が不適切であることや表面電極ゆえの問題が生じたが,本研究で提案してきた手法により,簡単なパラメータ調整だけでフィードバックFES制御を実現できることを確認した. 3.健常被験者で,肘関節の角度が異なる条件で手関節の制御実験を行い,姿勢変化により制御能力に差が現れることを確認した.制御対象に2関節筋を含む場合には,制御器のパラメータを変更する必要があることが示唆された.また,制御中の刺激振幅値に応じてPID制御器のパラメータを変化させる方が,より適切な制御を行える可能性があることも確認された.
Control Principle of Motor Units in Neuro-Muscular Systems

FUTAMI Ryoko, KANO Shinichiro, WATANABE Takashi, HOSHIMIYA Nozomu, HANDA Yasunobu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (C)

Institution: Tohoku University

1998 - 2000

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To make the FES-restoration of paralyzed motor function more rational, it is required that the nonlinear and time-variant muscle contraction dynamics is modeled. We built an activation model with emphasis on the calcium liberation from and re-sequestration into the sarcoplasmic reticulum, including calcium-induced calcium release. The model had two stable equilibrium points in the calcium concentration. Changes from the low to the high equilibrium point could be produced by high frequency trains of input pulses and would account for the potentiation. The model also showed a catch-like effect, as a long-lasting increment of muscle force after the application of single pulse. We also developed a method for detecting nerve action potentials (APs) from noisy signals. This method can be applied to the decomposition of electro-myograms, which are the population of action potentials from motor units. Multiresolution analysis was used for detecting APs under low SNR condition. Multivariate analysis was used to estimate single-unit activity from multi-unit activity recordings. APs produced by an individual unit have a characteristic waveform depending on factors such as the size of the fiber and the distance between the fiber and the recording electrode. Therefore, APs were classified into each unit based on their waveforms.
Research and Development of Simulation System for Restoring Motor Functions of Paralyzed Extremities by FES

HOSHIMIYA Nozomu, KANOH Shin'ichiro, WATANABE Takashi, FUTAMI Ryoko, HANDA Yasunobu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B).

Institution: Tohoku University

1998 - 2000

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(1) Musculoskeletal model was developed and computer simulation of standing up motion was implemented. Generation of stimulation data for standing up motion was achieved by the computer simulation using the musculoskeletal model with the optimizing method. Comparison between EMG signals of normals and the generated stimulation data showed that the method of using model simulation and the optimization was effective in generating standard stimulation data. (2) Torque generator model and parameter identification method of the model was proposed for representation of a certain patient. Computer simulation could predict responses caused by stimulating one knee extensor muscle of a normal subject. A musculoskeletal model including nonlinear characteristics and geometric structure of the musculoskeletal system was also studied. Part of experimental results with normal subjects was predicted after parameter tuning by trial and error manner. (3) For modeling of nonlinear and time variable characteristics, i) it was found that muscle potentiation occurred at 20Hz of stimulus frequency that used in clinical applications of FES.ii) M-waves and near infrared spectroscopy was found to be useful in muscle fatigue detection. iii) muscle activation model based on the playsiology was developed ant predictions of the potentiation and the catch property in muscle response was predicted by the model. (4) A detection method of control commands that were represented by specific movements was proposed for system operation by motor disabled patients. Movements of normal subjects and a C5-6 qtuadriplegic patient measured by a 3 dimensional position sensor or an accelerometer could be recognized by an artificial neural network. (5) A method of reaching target detection was proposed for arbitrary reaching restoration assuming patients who used the wheelchair. Reaching target detection system was composed of a laser pointer and 3 dimensional position/angle sensors. The detection system was found to be useful in practical.
Detection and classification of neural information from peripheral nerves

HOSHIMIYA Nozomu, KANOH Shin'ichiro, WATANABE Takashi, FUTAMI Ryoko, HANDA Yasunobu

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B).

Institution: Tohoku University

1998 - 2000

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The functional electrical stimulation (FES) is used to restore the loss of voluntary motor function caused by the spinal cord injury or the cerebral apoplexy. Less effective for restoration in the presence of the disturbance and muscle fatigue because of open-loop control system are problems of the current FES system. For developing closedloop FES system with natural sensors, we studied biocompatible and low noise electrodes, and method extraction of neural information from peripheral nerves. Fatigue properties and noise characteristic of stainless steel SUS316L, Co-Cr based alloy NAS604PH and newly developed high nitrogen high manganese austenitic stainless steel NAS 106N were investigated. We found that each electrode did not generate excess noise, and NAS106N had higher fatigue life than SUS316L and NAS604PH in both air and saline solution. A model of peripheral nerve was developed. We found that the distance between Ranvier's node and the recording electrode influenced on the recorded waveforms of nerve action potentials and it was possible to identify activity of each nerve fiber based on the recorded waveforms even if diameter and property of membrane of each fiber were similar and each fiber was close in nerve trunk. For clinical application of closed-loop FES system with natural sensors, the recording device must be placed stably and give minor damage to nerve fiber. Cuff electrode satisfies these requirements. However, it sometimes provides recordings whose signal-to-noise ratio is too low to detect action potentials. We used wavelet transform to detect action potentials under low signal-to-noise ratio condition. Our method provided reliable result. Moreover, we proposed the method for classification of action potentials to estimate single-unit activity with cluster analysis and the criterion for deciding the number of groups that action potentials were classified into. It provided reliable result.
機能的電気刺激(FES)による任意のリーチング動作の再建に関する研究

渡邉高志

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 奨励研究(A)

Institution: 東北大学

1998 - 1999

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本研究では、再建したい動作のための刺激データをあらかじめ用意しておくのではなく、患者の意志に応じて、実時間的に刺激データを生成して任意の動作を実現するためのFESシステムのインターフェイスを研究した。特に、上肢の運動機能再建に不可欠な"リーチング"を、障害者がFESによって自由に再建することを目的として、リーチングの目標位置検出について研究を行なった。また、 FES による任意の動作再建の一つとして、片麻痺者がシステム操作を意識しないで様々な条件下で歩行を容易に行えるEFSシステムのインターフェイスについても研究を行った。今年度は、これらの研究に関して、以下の成果を得た。 1.昨年度、重度四肢麻痺者への適用を想定し、残存する頭部の随意動作から目標位置の三次元座標を検出する装置を試作した。このシステムの評価と検出精度の向上を検討するために、ヒトを模擬する実験装置を製作した。頭部の前屈及び回旋が可能であり、頭部に座標検出装置を装着して、机上の点を指示することを可能にした。 2.これまでの座標検出法について、使用したレーザポインタの材質を磁気センサに影響の無いものに変更し、また、磁気センサーのレシーバを2つにして精度の向上を試み、上記1で製作した実験装置を用いて三次元座標検出装置の評価を行った。机上に設定した複数の目標点を指示する実験を行い、磁気センサに対する周囲からの外乱がない場合には0.41〜1.45cmの距離の誤差で座標を検出できた。 3.任意の動作を再建するためのインターフェイスとして、片麻痺者の歩行動作の再建を想定し、歩行中の加速度を計測してニューラルネットにより歩行状態を自動的に識別し、制御命令として利用することを検討した。健常被験者での歩行についてであるが、平地歩行、階段昇り、階段降りについては80%以上の識別率を得ることができた。
機能的電気刺激による麻痺肢制御法の最適化のための基礎研究

渡邊高志

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 奨励研究(A)

Institution: 東北大学

1996 - 1996

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機能的電気刺激(FES)による麻痺肢の運動機能再建の臨床的実用性をさらに向上させるために、臨床におけるFESシステムの生体工学的基礎を確立する事を目的とし、以下の研究を進めた。 1.速筋・遅筋といった異なる特性を有する筋の刺激周波数-張力特性を解析し、筋・腱系の基本的な電気刺激応答モデルとして、刺激強度及び刺激周波数を入力とする筋・腱モデルを構築した。ここでは、先に得られた速筋・遅筋といった筋の異なる特性を、電気刺激による筋活動レベルの刺激周波数依存性に反映させた。 2.3リンク骨格モデルを構築し、簡略化した筋・腱系のモデルを用いて、筋・骨格系の運動モデルを構築した。また、等尺性条件下での筋張力について、構築した筋・骨格モデルによるシミュレーション結果と、健常者での刺激実験による結果とを比較し、筋腱系-骨格系の結合形態に関する検討を加えた。 3.FES制御のためのフィードバック情報等を神経活動電位から検出する事を目的として、外的な機械的刺激により発生した神経インパルス群を計測し、それらを誘発する刺激の種類をそれらの神経インパルス波形から推定する方法について検討した。本研究ではクラスタリング手法を採用し、計測した神経インパルス波形から、与えた機械的刺激を推定可能であることを確認した。 4.尿失禁をFESにより防止することを目的として、閉ループ制御を考慮した新たな刺激方式の検討を行った。尿道閉鎖に関与する筋は、左右の陰部神経による両側性の神経支配があるので、各神経束に印加する刺激パルスの位相をπずらす刺激方法を検討し、超神経束を同位相で刺激する場合に比べて短時間の高尿道収縮力を得る場合に適している事を示唆した。また、長時間の低尿道収縮力を維持する場合には、各神経束を交互に単独刺激する方法が有効である事を示唆する実験結果を得た。
Electronic External Control of the Neuromuscular System

HOSHIMIYA Nozomu, HANDA Yasunobu, MURAKAMI Hajime, WATANABE Takashi, FUTAMI Ryoko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for Scientific Research (B)

Institution: Tohoku University

1994 - 1996

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(1)Models of the neuromuscular and the skeletal systems were developed based on results of analyzing responses of the neuromuscular system during electrical stimulation. Then, a basic simulation system of FES-induced motions for the paraplegics was developed. A stimulation pattern for standing up was made up automatically on the simulation system using the dynamic optimization. (2)It was verified that linear interpolation of EMG patterns and artificial neural network could be used for stimulation pattern generation. In addition, a system that patients could modify stimulation patterns without medical knowledge was developed and its capabilities were verified in experiments of controlling normal subjects' wrist angles. (3)The error detecting and correcting circuit (ECC) based on the Hamming coding was applied to an experimental implantable FES system for rejecting influence of external electromagnetic noise. Improvement of the reliability of transmitted stimulation data by using the ECC was verified on the preliminary implantable FES system. (4)It was suggested that the following two methods were useful in FES control for preventing the incontinence : 1) 180 degrees shift of the phase between stimulus pulses applying to the left and right pudendal nerves for high urethral closing force in short time. 2) stimulation to one of the pudendal nerves alternately for long time low closing force of the urethra. (5)Waveforms of nerve action potentials elicited by external mechanical stimulation were analyzed for extracting information for feed back control in FES application. Cluster analysis was found to be useful for estimating the stimulation that elicited the nerve signals. (6)Methods of getting control commands for FES system, which were based on the posterior auricular muscle, the tongue movement, and head movement identification by artificial neural network e.g. nodding, were confirmed to have fundamental feasibility of using in clinical application.
非線形時変特性を有する神経・筋系の機能的電気刺激による制御のための基礎研究

渡邉高志

Offer Organization: 日本学術振興会

System: 科学研究費助成事業

Category: 奨励研究(A)

Institution: 東北大学

1995 - 1995

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本研究では、FESの臨床応用のための生体工学的基礎を確立するために、神経・筋系の電気刺激応答特性の計測と解析、ならびに、そのモデル化と制御法に関する以下の検討を行った。 1.異なる特性を有する速筋及び遅筋の刺激周波数-張力特性を測定し、それらの差異を解析して、FESシステムの制御能力の向上を図るとともに筋特性を考慮した刺激変調方式を確立するための考察を行った。これより、パルス振幅変調と周波数変調を組み合わせて利用する制御方法の有用性を示唆した。 2.FESにおいて、刺激データの作製・修正や、再建動作のシミュレーションを行うこと等を目的として、電気刺激を入力する筋系のモデル化を進めた。特に、筋の刺激周波数-張力特性によりモデルの一部を記述し、その基本的なモデル化を行った。次に、構築した筋モデルのシミュレーションにより、電気刺激による近似的な筋応答を出力可能でありながら、過去の随意運動のモデルに見られるような複雑さを簡略化でき、かつパラメータが取り扱い易いといった利点があり、臨床応用への展開を期待できることを示した。 3.姿勢を保持するための閉ループ制御機能を有する実験的FESシステムを構築し、電気刺激による神経筋骨格系の応答計測を通して、閉ループ制御アルゴリスムの基礎的な検討を行った。ここでは、パルス振幅変調により動作を再建し、パルス幅変調により姿勢保持の閉ループ制御を行う方法を提案し、健常者の手関節角度制御実験を通して、その有効性を確認した。 4.現在のFESシステムの課題の一つとして、システムの操作性の向上が挙げられることから、その制御命令として、あらゆる患者が利用可能な舌動作について検討を行い、原理的な可能性を確認した。
Fundamental Study of Simultaneous Antagonistic Situmilation by FES and Modeling Study of the Neuromusculoskeletal System

HOSHIMIYA Nozomu, FUJITA Kinya, HANDA Yasunobu, WATANABE Takashi, MURAKAMI Hajime, FUTAMI Ryoko

Offer Organization: Japan Society for the Promotion of Science

System: Grants-in-Aid for Scientific Research

Category: Grant-in-Aid for General Scientific Research (B)

Institution: Tohoku University

1992 - 1993

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Electrical stimulation to the neuromusculoskeletal system causes nonlinear response. The purpose of this research is to make clear the response by simultaneous antagonistic stimulation in order to develop the method of improving the nonlinearity, and to have knowledge for modeling that system responding to electrical stimulation. Following results were obtained by this research. 1. Experimental system for measuring the response of neuromusculoskeletal system caused by electrical stimulation was achieved. It was confirmed that steepy rising slope of Stimulus Intensity-Force characteristic of the agonist became gradual by simultaneous antagonistic stimulation. This shows that the simultaneous stimulation method is useful for controlling parapyzed extremities by functional electrical stimulation (FES). In addition to the results, 2. It was suggested by the slope changes of the Intensity-Force characteristics that the muscle length affected the response of simultaneous antagonistic simulation, and the effect was not observed after eliminating the innervation. From these results, contribution of the neuromuscular system containing the spinal cord reflex to the slope change as obtained. 3. A new method of making stimulation pattern, in which consecutive motion is divided into some "elemental movements" and stimulation pattern of the original mortion is made up by combining their stimulation patterns, was proposed. Validity of the method was confirmed by fundamental EMG analysis and knowledge of influence of the gravity on making stimulation pettern and on modeling the neuromusculoskeletal system was obtained. 4. Stumulation pattern is finally adjusted in clinical application. In order to develop the FES system for easily modifying stimulation pattern, control command detector for FES system and modification method of stimulation pattern were studied. Those were effective and the useful knowledge for developing the practical FES system was obtained.

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Social Activities 1

中学生のためのコンピュータグラフィクス講座－３Dゲームを作ろう－

2002/12 - 2007/12

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中学生を対象としたコンピュータ・グラフィクス講座を開講した．

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腓腹筋電気刺激で蹴り出し強化を行う歩行補助装置の開発

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高齢者や歩行障害者は蹴り出し動作が弱く歩行速度が遅くなり，左右へ身体がぶれるため，転倒危険性が非常に高い．そこで，腓腹筋電気刺激を用いて蹴り出し動作を強化することにより，膝関節及び股関節の運動を誘発して歩容を改善する．同時に転倒危険性を低下でき，歩行速度も増加させ得る歩行補助装置を高齢者や歩行障害者に提供できる．
cycle-to-cycle制御によるFES歩行補助・制御に関する研究

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cycle-to-cycle制御によるFES歩行補助・制御に関する研究
中枢性下肢麻痺者の歩行運動再建システムの開発

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脊髄損傷や脳卒中などによる中枢性の下肢麻痺者の多くに対して実用的な歩行を提供できる運動機能再建手法はこれまでなく，下肢に対する機能的電気刺激（FES）によって歩ける患者は上肢機能が特に優れる場合に限られていた．本研究は，下肢麻痺者の歩行運動の再建に関して，これまでの研究成果では不十分であった部分を補うための問題解決と制御手法の開発を行い，より多くの肢体不自由者のさらなる社会参加を可能にすることを目指す．本研究では，実用性と実現性の高い方法を重点的に進め，下肢麻痺者の歩行運動再建システムの基盤技術を開発する．まず，閉ループ制御や歩行中の制御命令の取得，さらには，FESによる歩行再学習システムに利用するために，両側下肢の関節角度を簡便に計測可能な身体装着型姿勢計測システムを臨床的に利用できるように開発する．また，両脚支持期を含めた歩行全体のシミュレーションが行えるように，下肢のFES応答モデルの改良を行う．これを利用して，杖を用いた安全な歩行機能に着目し，FES歩行のための各種制御アルゴリズムの開発と評価を行えるようにする．一方，不全麻痺者では，FESによる歩行再建の実現性及び実用性が高いことがこれまでの検討結果から確認されたので，不全麻痺者に対する筋電制御による筋力増強制御方式の開発を進める．そして，脳波および眼電図から患者の意図を抽出し，それによりFES制御装置の操作を行うシステムについて検討を行い，FESシステムにおける新たなヒューマンインターフェースシステムの開発を目指す．上記の基盤技術を統合し，FESを利用して歩行機能を提供する手法を開発し，下肢麻痺者の歩行再建システムを実現することで，下肢麻痺者が車椅子で移動した後に，FESの補助のもとで自分の筋力で立って室内等の範囲を移動することが可能になり，より患者の家庭内自立や社会的自立を促し，介護者の負担をも軽減すると期待される．