A passively safe cable driven upper limb rehabilitation exoskeleton.

<bold>Background: </bold>When using upper limb exoskeletons that assist the movement of physically weak people, safety should be the most important index.<bold>Objective: </bold>In this paper, a passively safe, cable-driven upper limb exoskeleton with parallel actuated joints, which perfectly mimics human motions, is proposed.<bold>Methods: </bold>Compared with the existing upper limb exoskeletons which are mostly designed only considering the realization of functional properties, and having poor wearabity, a passively safe prototype for motion assistance based on human anatomy structure has been developed in our design. This design is based on the prior exoskeleton structure with the adoption of a gravity balanced device.<bold>Results and Conclusion: </bold>The gravity balanced mechanism was confirmed in theory and simulation, showing it has a positive effect on balance. [ABSTRACT FROM AUTHOR]