An Analysis of Recovery Motion of a Man Wearing Physical Assistant Robot in Response to Collision

Physical assistant robots are expected to be able to assist in our working and daily lives. However, safety problems arise when robots are used in indoor environments with obstacles. The focus of this study was on collision of the side of a robot with an obstacle, and the recovery motion after the collision was measured. A healthy young man participated in this experiment. Two different types of recovery motions were observed. These two motions differed in the degree of deceleration of the body rotation in the horizontal plane. The part of the robot and the timing of the collision with the obstacle affected the recovery motion strategy. A collision at the hip side in the middle swing phase might be the most severe condition from which to recover, among those considered in this study. The results of this study will be helpful in improving the safety of the use of physical assistant robots.