Power assist method based on phase sequence driven by interaction between human and robot suit

Abstract

We proposed a power assist method for leg based on the autonomous motion driven by the interaction between human and the robot suit, HAL (hybrid assistive limb) and verified the effectiveness of this method in the experiments in walking. In order to perform walking task autonomically, we used a phase sequence control which generates a task by transiting some simple basic motions called phase. A task was divided into some phases on the basis of the task performed by a normal person. The joint moving modes were categorized into the active, passive and free modes according to the characteristic of the muscle force conditions. The autonomous motion which HAL generates in each phases were designed according to one of the categorized modes. The floor reaction force and joint angle were adopted as the condition to transit each phase. The experiments in power assist were performed for normal person. The experimental results showed that the muscle activation levels in each phase were significantly reduced. With this, we confirmed the effectiveness of the proposed assist method.