Perception-Assist with a Lower-Limb Power-Assist Robot for Sitting Motion

A lower-limb power-assist robot is expected to assist physically weak persons to walk, stand up, or sit down. However, since the environment perception ability of the physically weak persons is sometimes deteriorated also, falling accident might occur even though the power-assist is applied. A concept of perception-assist has been proposed to avoid an unexpected accident. This paper proposes a perception-assist method that the robot monitors interaction between the user and the surrounding environment and modifies the user´s motion if it is necessary. In the case of sitting on the chair which is not located in a proper position, the robot performs the perception-assist to modify falling motion to squatting motion by adding the additional force from behind. The effectiveness of the proposed method was evaluated by performing the experiments.