Development and control of a 3DOF upper-limb robotic device for patients with paretic limb impairment

• Main Authors: Fatai, Sado, Sidek, Shahrul Na'im, Md. Yusof, Hazlina, Hafiz, Latif M., Babawuro, Adamu Y.
• Format: Article
• Language: English
• Published: Asian Research Publishing Network (ARPN) 2015
• Subjects: TA164 Bioengineering
• Online Access: http://irep.iium.edu.my/47310/1/IJCAS_vo_4-no3.pdf; http://irep.iium.edu.my/47310/; http://www.arpnjournals.org/jeas/research_papers/rp_2015/jeas_1215_3176.pdf

Rehabilitation therapy after stroke is crucial to helping patients regain as much as possible the use of their paretic limbs. The major challenges, however, in conventional post-stroke rehabilitation therapy is that the therapy is labour intensive, time demanding, and therefore, expensive with consequent reduction in the amount of training session required for optimal therapeutic outcome. In recent times, the use of robotic devices for rehabilitation training has been widely favoured. Robot-assisted rehabilitation therapy is cost-effective, fatigue-free, and has the potential to improve the efficiency of the rehabilitation process. More so, positive outcome of improved motor control abilities for patients undergoing robot-assisted therapy have been widely recorded. This paper presents the development and control of a portable three degree of freedom (3-DOF) end-effector-type robotic device for upper-extremity rehabilitation of paretic stroke patients. The device has three active DOFs consisting of two revolute joints and one prismatic joint (R-R-P) designed to allow 3-dimensional range of motion (ROM) exercise for elbow and shoulder rehabilitation. A novel adaptive hybrid impedance control framework has been developed for the device to allow safe robot-patient dynamic interaction during planned repetitive range of motion exercises and to keep track of patients’ motor recovery based on an embedded Modified Ashworth Scale assessment criteria. Experimental results performed, using a healthy subject, to test and evaluate the ability of the device to track a planned simple flexion/extension range of motion exercise for the elbow joint showed position and force tracking accuracy to a maximum root mean square error (RMSE) of 0.024m and 0.343N respectively which indicate the possibility of use of the device for real patients.