Combined kinematic analysis of a hybrid 7-DOF rehabilitation robot

It is well known that stroke is the leading cause of long-term disability and the number of stroke patients has been increasing due to the ageing of the population worldwide. Over the past decade, the effort to deliver effective rehabilitation robots especially for stroke patients has also been growing steadily with aims to provide timely and effective recovery, thus to reduce overall healthcare service burden. The trend of technical development has been evolving from the passive or one-way assistance regardless of patients' intention or acute physical status toward the interactive therapy taking into account force/torque feedback and movement intention of the patients along with the therapy. Currently, few systems in the market, however, have considered the relative coordinate change of the patients' upper limb, especially the center of humerus head into robot therapy. Here, we have developed a 7-DOF exoskeleton robot system for stroke rehabilitation of the upper extremity. The robot has three motors for the shoulder rotation and one for the elbow actuation. A key differentiating feature of this robot is the additional 3-DOF full shoulder motion control designed to build more ergonomic system, which provides a more user-friendly therapy by making the patient posture more natural. As the first step for the robotic control, this paper describes the combined kinematic analysis of the 7-DOF rehabilitation robot.