Assist as needed control strategy for upper limb rehabilitation robot in eating activity

Zainul Azlan, Norsinnira and Lukman, Nurul Syuhadah (2020) Assist as needed control strategy for upper limb rehabilitation robot in eating activity. IIUM Engineering Journal. ISSN 1511-788X E-ISSN 2289-7860

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Abstract

The slacking behaviour or lack of participation from impaired patients during robotic rehabilitation therapy is one of the factors that slows down the recovery speed. The implementation of Assist As Needed (AAN) control law in the robotic assisted rehabilitation treatment may alleviate this problem and encourage the patients to be actively involved in the rehabilitation exercises. This paper presents a new Assist As Needed control strategy for an upper limb rehabilitation robot in assisting subjects with various level of capabilities to regain their original upper limb’s functionality in realizing basic motions in eating activity. The controller consists of Proportional, Integral, Derivative (PID) controller in the feedback loop, with an adjustable gain K that varies according to the user’s level of capability. A Force Sensing Resistor (FSR) is used to identify the user’s upper extremity capability level. The controller regulates the necessary amount of assistance provided by the robot based on the information obtained from the sensor. The automatic adjustment of the robot’s assistance to the subjects leads them to put in their own effort in accomplishing the desired movements. The proposed control strategy is simple, easy to be programmed and mathematically less complicated. A prototype of the wearable upper limb rehabilitation robot has been built and a Graphical User Interface (GUI) has been developed using MATLAB software to facilitate the rehabilitation process and for progress monitoring. The simulation and experimental results have proven that the proposed control strategy is successful in regulating the necessary amount of robot assistance according to the patients’ level of capability. The proposed controller has effectively driven the upper limb rehabilitation robot to achieve the desired trajectory with zero steady state error, percentage overshoot less than 8% and settling time below 6 seconds, whilst providing the correct amount of robotic assistance in accordance to the subjects’ capability level. ******************************************************************************************************** Tingkah laku kurang penyertaan dari pesakit yang kurang berkeupayaan semasa terapi pemulihan robotik merupakan salah satu faktor yang melewatkan kadar pemulihan. Pelaksanaan teknik kawalan Assist As Needed (AAN) dalam rawatan pemulihan dengan bantuan robot dapat mengurangkan permasalahan ini dan mendorong pesakit untuk terlibat secara aktif dalam latihan pemulihan. Artikel ini membentangkan strategi kawalan Assist As Needed yang baru untuk robot pemulihan bagi tangan pesakit-pesakit yang terdiri daripada pelbagai tahap kemampuan, dalam mengembalikan fungsi tangan yang asal dalam merealisasikan gerakan asas dalam aktiviti makan. Teknik kawalan yang diusulkan terdiri daripada pengawal Proportional, Integral, Derivative (PID) dalam gelung maklum balas, dengan parameter K yang boleh diubahsuai mengikut tahap kemampuan pesakit. Alat pengukur Force Sensing Resistor (FSR) digunakan untuk mengenal pasti tahap kemampuan pengguna dalam melakukan gerak kerja tangan. Teknik kawalan yang dibentangkan mengatur jumlah bantuan yang perlu diberikan oleh robot kepada pesakit berdasarkan maklumat yang diperoleh daripada sensor. Penyesuaian jumlah bantuan yang dibekalkan oleh robot kepada subjek secara automatik akan mendorong mereka bagi sama-sama meletakkan usaha mereka sendiri dalam melakukan pergerakan yang ditetapkan. Strategi kawalan yang dicadangkan ini adalah ringkas, mudah diprogramkan dan kurang rumit dari segi matematik. Sebuah prototaip robot pemulihan anggota tangan telah dibina dan sebuah platform grafik bagi pengguna (Graphical User Interface, GUI) telah dibangunkan menggunakan perisian MATLAB bagi memudahkan proses pemulihan dan pemantauan kemajuan pesakit. Hasil daripada simulasi dan eksperimen yang telah dijalankan membuktikan bahawa strategi kawalan yang dicadangkan berjaya mengatur jumlah bantuan daripada robot supaya bersesuaian dengan tahap kemampuan pesakit. Teknik kawalan yang dicadangkan telah berjaya menggerakkan robot pemulihan tangan untuk mencapai lintasan pergerakan yang diinginkan dengan ralat sifar pada keadaan stabil, peratusan ayunan berlebihan kurang daripada 8%, masa penyelesaian di bawah 6 saat dan dalam masa yang sama, memberikan jumlah bantuan robotik yang tepat, bersesuaian dengan tahap kemampuan subjek

Item Type:	Article (Journal)
Additional Information:	4494/85230
Uncontrolled Keywords:	Assist-As Needed Control, Upper Limb Rehabilitation Robot, Control Input Regulation, PID Controller and Eating Activity
Subjects:	T Technology > TJ Mechanical engineering and machinery T Technology > TK Electrical engineering. Electronics Nuclear engineering
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Engineering Kulliyyah of Engineering > Department of Mechatronics Engineering
Depositing User:	Norsinnira Zainul Azlan
Date Deposited:	25 Nov 2020 17:13
Last Modified:	29 Jun 2021 08:26
URI:	http://irep.iium.edu.my/id/eprint/85230

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