ARMin III — arm therapy exoskeleton with an ergonomic shoulder actuation

摘要

Rehabilitation robots have become important tools in stroke rehabilitation. Compared to manual arm training, robot-supportedtraining can be more intensive, of longer duration and more repetitive. Therefore, robots have the potential to improve therehabilitation process in stroke patients. Whereas a majority of previous work in upper limb rehabilitation robotics hasfocused on end-effector-based robots, a shift towards exoskeleton robots is taking place because they offer a better guidanceof the human arm, especially for movements with a large range of motion. However, the implementation of an exoskeletondevice introduces the challenge of reproducing the motion of the human shoulder, which is one of the most complex jointsof the body. Thus, this paper starts with describing a simplified model of the human shoulder. On the basis of that model, anew ergonomic shoulder actuation principle that provides motion of the humerus head is proposed, and its implementationin the ARMin III arm therapy robot is described. The focus lies on the mechanics and actuation principle. The ARMin IIIrobot provides three actuated degrees of freedom for the shoulder and one for the elbow joint. An additional module providesactuated lower arm pro/supination and wrist flexion/extension. Five ARMin III devices have been manufactured and they arecurrently undergoing clinical evaluation in hospitals in Switzerland and in the United States.