Passive velocity field control based movement support rehabilitation system for paralysis patients

Abstract

When the movement-assist type rehabilitation robot operation, the disturbance caused by a paralyzed part has often strong nonlinearity. In this study, we focused on the passive velocity field control (PVFC) which uses a velocity field for track following and keeps the passivity of the system. The PVFC controlled system tracks following the pre-designed velocity field when the disturbance not exists, but when the disturbance occurs the system stops following because of the passivity. However, normal PVFC easily stops even if a small disturbance force, therefore in this paper, we added a torque assistance term for preventing the disturbance to the PVFC controller. Using this method, the PVFC only works when the disturbance torque over the setting value. The feasibility of the proposed method for a rehabilitation robot was shown by the experiment.