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.