Wearable cable-driven upper arm exoskeleton - motion with transmitted joint force and moment minimization

Safety is a critical issue for upper arm exoskeletons intended for human use. Joint forces and moments experienced by a human user during motion must be minimized to ensure safety. Trajectory planning and control of cable-driven exoskeletons is challenging due to the unique property that cables can transmit forces only in tension. This paper introduces the design of a 4-DOF cable-driven upper arm exoskeleton and schemes for trajectory planning and control. Simulations show that in most cases a feasible point-to-point trajectory can be generated while minimizing reaction joint forces and moments.