Nonlinear Sliding Mode Control Implementation of an Upper Limb Exoskeleton Robot to Provide Passive Rehabilitation Therapy

Abstract

Treatment for upper extremity impairment following a stroke or other conditions relies on rehabilitation programs, especially on passive arm movement therapy at the early stages of impairment. An exoskeleton robot (ETS-MARSE) was developed to be worn on the lateral side of upper-limb to rehabilitate and assist daily upper-limb motion. We have implemented a nonlinear sliding mode control technique to maneuver the ETS-MARSE in providing different passive rehabilitation exercises that include single and multi joint movement exercises. To evaluate the robustness and tracking performance of the controller, exercise involving healthy human subject were performed, where spasticity (a resistance) on arm movement which often found to subjects following a stroke was added artificially. Experimental results show the efficient performance of the controller to maneuver the exoskeleton to provide passive rehabilitation therapy.