Development of a Hand-Assist Robot With Multi-Degrees-of-Freedom for Rehabilitation Therapy

This paper presents a virtual reality (VR)-enhanced new hand rehabilitation support system that enables patients to exercise alone. This system features a multi-degrees-of-freedom (DOF) motion assistance robot, a VR interface for patients, and a symmetrical master-slave motion assistance training strategy called "self-motion control," in which the stroke patient's healthy hand on the master side creates the assistance motion for the impaired hand on the slave side. To assist in performing the fine exercise motions needed for functional recovery of the impaired hand, the robot was constructed in an exoskeleton with 18 DOFs, to assist finger and thumb independent motions such as flexion/extension and abduction/adduction, thumb opposability, and hand-wrist co- ordinated motions. To enhance the effectiveness of the exercises, audio-visual instructions of each training motion using VR technology were designed with the input of clinician researchers. Experimental results from healthy subjects and patients show sufficient performance in the range of motion of the robot as well as sufficient assistance forces.