A study on motion modification force in perception-assist for a lower-limb power-assist exoskeleton

Power-assist systems have been studied actively in these days. The motion of physically weak persons can be assisted by the power-assist systems. On the other hand, not only the motor ability, but also the sensory ability is sometimes deteriorated in the case of a person who needs the assist of the power-assist systems. Perception-assist is one of the methods to assist the sensory ability for such person. In the perception-assist, the user´s motion is automatically modified by the power-assist robot if it is necessary. This paper presents a method to distribute the motion modification force to multiple joints considering the user´s joint movable ranges and energy efficiency. A null space is applied to take into account the user´s joint movable ranges. The experimental results showed the effectiveness of the proposed method.