Forced oscillation control with a wearable reaction wheel to assist human periodic arm swing

Abstract

Rehabilitation for stroke patients includes periodic arm exercises, but these require assistance by caregivers at the start of the exercise, which is a burden for caregivers. In this study, we have developed a system with three reaction wheel mechanisms, which can generate not only moments in each direction but also a larger moment than the output of a single axis by interlocking the axes. In addition, by using forced oscillation control, it is possible to assist the movement of the wearer's periodic arm swing even if the weight and output moment of the reaction wheel is not large. Although a large torque of 2.65 Nm is required for the system to swing the arm, it was confirmed that the developed device can be used to increase the amplitude of arm oscillation and achieve an oscillation frequency equivalent to that of a human arm swing, even with a single reaction wheel exerting a torque of 0.4 Nm.