Design and evaluation of a single-size mechanically self-aligning upper limb exoskeleton

Abstract This work describes the design and validation of a one-size-fits-all assistive exoskeleton for the upper limb that is self-adjustable to the wearer subject. The assistance function is performed even if the joints of the exoskeleton are not aligned with the joints of the subject; therefore, it does not require personalized adjustments during the wearing phase. The device is composed of a distal articulated system with a prismatic interface towards the body segment and a flexible proximal architecture that shifts the actuation towards the pelvis to limit the alteration of the subject’s center of gravity. In vivo experiments in the laboratory demonstrate the ability to alleviate muscular effort, and home-based experiments in performing daily activities show excellent perceived usability and acceptability in an elderly population. Furthermore, a proposed biomechanical model estimates the ability of the exoskeleton to contain the joint constraint reactions in the subject during the assistance phase.