Variable compliance control for transfer support robot

Recently in Japan, increase in necessity of nursing care with elderly society has been problematic. Transfer task of a person in need of nursing care is one of the heavy load for care-worker. Additionally, the problem of the privacy protection for the disability in the private space such as a toilet and bath is a serious issue. Therefore, the aim of this research is to develop the transfer support robot which enables to promote the independence of the disability in the private space. In this paper, as the first step of the realization, the necessary movements and controls are clarified. The newly-designed variable compliance control method is proposed. In the proposed method, compliance control is applied to the position control based control system. The stiffness of the robot changes smoothly based on the information of disturbance force caused by human motion and weight. It means that safety cooperative work is possible even when humans perform irregular movements. By the proposed method, when a disturbance force occurs downward direction due to a human weight, the robot has highly stiffness value. When a disturbance force occurs upward direction due to a human motion, the robot has lowly stiffness value. The validity of the proposed method was confirmed by simulation and experiment using a 2-link manipulator imitate the transfer support robot.