Design and Control of a Seven Degrees-of-Freedom Semi-exoskeleton Upper Limb Robot

Previous studies have shown that patient’s voluntary participation is one of the key factors in improving rehabilitation effects. End-effector and exoskeleton type robots have been developed to support rehabilitation training at different impedance levels. However, these robots either fail to take the movement of the shoulder girdle into account or suffer from complex and massive shoulder mechanisms. In this paper, we merge the advantages of the end-effector and exoskeleton type robots and propose a simple and effective semi-exoskeleton upper limb robot with seven degrees of freedom to support the impedance training of the human shoulder complex and elbow joint. Besides, an admittance control scheme is developed to generate desired movements during training. Experiments on five subjects are conducted to assess the feasibility and performance of the proposed robot. Results show that the proposed robot has satisfactory performance in terms of shoulder kinematic compatibility and human-robot interaction. This study could pave way for a practical rehabilitation robot for patients with stroke in real-life.