Design and control of the Active A-Gear: A wearable 5 DOF arm exoskeleton for adults with Duchenne muscular dystrophy

Adults with Duchenne muscular dystrophy (DMD) can benefit from active arm supports that augment the residual motion capabilities of their arms. While there is a considerable number of active exoskeletons commercially available for rehabilitation purposes, no active exoskeletons for supporting the arm function during the performance of activities of daily living (ADL) are available. In this paper, we present the Active A-gear, a wearable five degree-of freedom exoskeleton that has been specially developed to assist people with DMD for the performance of ADL. The Active A-Gear is built upon our previous design of the passive A-Gear, thus combining active and passive support. The Active A-Gear can be controlled using force-based (admittance) control. We report the results of the system verification, which included endpoint position bandwidth, workspace, weight, joint speed, endpoint force and joint backlash measurements. A pilot evaluation was carried out with one healthy subject (27 years-old) performing ADL. The results of the verification and evaluation tests indicate that with some modifications the Active A-Gear is a suitable platform to test the functional performance and feasibility of a wearable and active support for adults with DMD.