Motion control of a robotic device for passive rehabilitation of human shoulder and elbow joint movement

Abstract

Stroke is one of the main cause of upper limb dysfunction. The number of individuals who lost upper limb function due to stroke is increasing day by day and is projected to continue increasing at an alarming rate in United States. Repetitive movement therapy has been the main method to regain lost mobility. We have designed 3 degrees of freedom (DOF) wearable robotic assistive device to provide passive rehabilitation for shoulder (abduction-adduction and vertical flexion-extension) and elbow (flexion-extension) to those patients. A nonlinear computed torque control technique is used for dynamic simulation of the robot. Simulated results show that the controller can effectively maneuver the robot to follow the reference trajectories (passive rehabilitation exercises). To simulate the spasticity and to check the robustness of the controller disturbances were added in each joints and tracking performance of the controller was further evaluated. Excellent tracking performance of the controller was observed in this case as well with error in tracking less than 0.05°.