Developing a whole-arm exoskeleton robot with hand opening and closing mechanism for upper limb stroke rehabilitation

There is a lack of enough attention to the patients´ hand posture. When robots implement assistive training, patients are often asked to grip a handle tightly, which may induce strong hand muscle contractions with the hand at an abnormal posture. If we ignore proper control of the muscle tension of subject´s hand, the flexibility of hand/fingers may decrease and the robot training may potentially cause abnormal muscle tone. On the other hand, since the patient´s fingers are already in an abnormal posture, properly aligning the joint and making the robot easy to attach is important. However, an existing multi-DOF hand exoskeleton systems may be difficult for the patients to put it on. the purpose of this paper was to design a patient-friendly mechanism drive by a single motor and attached to the whole-arm rehab robot for the hand and finger opening and closing functions. Using our 8+2 DOF whole-arm robot including this hand opening and closing mechanism, a novel integrated rehabilitation is performed including 1) strenuous stretching of the MCP-thumb joints and other spastic joints of the upper limb; 2) active assistive exercise is provided to improve voluntary neuromuscular control by using robot-computer games with a griping task; 3) outcome evaluations including the cross-coupling torques between the fingers/thumb and the other joints during hand opening/closing and other upper limb movements.