A performance evaluation method of a passive type force display and rehabilitation system with redundant brakes

We developed a compact and low-cost quasi-3-DOF rehabilitation system ldquoHybrid-PLEMOrdquo for upper limbs of stroke patients. Hybrid-PLEMO has 2-DOF force feedback function in working plane, its working plane can be adjusted the inclination, and it can be switched between active type and passive type. However, there are some directions and link positions which are difficult to display the force when Hybrid-PLEMO works at passive type. Redundant brakes method had been suggested to made it possible to display various force directions and various postures of virtual objects by the improvement of the controllability. In this paper, a novel method is presented for performance evaluation of a passive-type force display system with redundant brakes. Using this method, we evaluate the performance of a 2-DOF passive-type force display system with and without redundant brakes, and draw a conclusion that it is good to add redundant brakes to the passive-type force display and rehabilitation system.