Tele-operation of a robotic exoskeleton for rehabilitation and passive arm movement assistance

A robotic exoskeleton, the MARSE-4 has been developed to provide passive rehabilitation therapy to the physically disabled individuals with impaired upper-limb function. In this paper we focused on the tele-operation of the MARSE-4 using an upper-limb prototype 7DoFs (lower scaled) master exoskeleton arm (mExoArm.) The MARSE-4 has 4DoFs and is able to assist elbow (flexion/extension), forearm (pronation/supination) and wrist joint movements (radial/ulnar deviation, and flexion/extension). Modified Denavit-Hartenberg conventions were used in the kinematic modeling of the exoskeleton. In control, a nonlinear computed torque control and a linear PID control techniques were employed to maneuver the MARSE-4 to follow the desired trajectory. Experimental results show that the MARSE-4 can efficiently track the desired trajectories as generated by mExoArm and therefore guarantee to tele-operate the MARSE to deliver passive therapy for wrist, elbow, and forearm movements.