Low cost and light-weight multi-DOF exoskeleton for comprehensive upper limb rehabilitation

To respond to increasing risk of stroke in elderly people, several robotic devices for rehabilitation of upper limb and hand have been developed. The devices for upper limb which are mostly operated in active manner have potential to cause subluxation at shoulder because they constrain natural movement of the shoulder joint (Glenohumeral joint). The devices for hand tends to be too heavy to wear during daily activities because hand has greater degrees of freedom (DOFs) requiring many actuating units. Thus, it is hard to find upper limb devices including both arm and hand devices although upper limb tasks require both functions. Through this paper, we introduce concept and development progress of a low cost and light-weight device which includes both upper arm and hand. This work-in-progress paper aims at reporting the design and evaluation of passive gravity compensating tracker mechanism for shoulder joint which is one of the key parts of the whole upper limb rehabilitation system.