Feasibility Study of Shoulder Joint Impedance Measurement While Assisting Arm Against Gravity Using a Rehabilitation Exoskeleton Robot

Assessment of patient joint stiffness during robotic upper extremity rehabilitation has the potential to expand the range of its adaptations. In this study, we investigated the feasibility of measuring shoulder joint impedance during arm weight compensation using an exoskeleton robot joint driven by an hybrid actuator. It is shown that, in principle, impedance measurement during assisting is possible by weight compensation by pneumatic force and perturbation application by electromagnetic force.