Standing assistance considering both load reducing and body stability adjustment

Abstract

In this paper, we propose a standing assistance scheme that uses a patient's own physical strength. In previous studies, conventional assistive robots did not require patients to use their own physical strength to stand, which leads to decreased strength in the elderly. Therefore, an assistive robot that allows patients to maximally use the physical strength they possess is desired. To realize this objective, we propose a standing assistance scheme that performs two functions, namely, motion assistance using a patient's own physical strength and posture adjustment. In general, human movements consist of voluntary movement, which mainly generates body motion, and posture adjustment, which keeps the body stable during motion. Our proposed scheme provides the minimum force that enables voluntary movement by patients with their remaining physical strength while keeping their body stable by performing posture adjustment. To perform these two functions simultaneously, we propose a body movement vector for dividing human motion into a voluntary movement and a posture adjustment action. A prototype assistive robot fabricated based on the proposed idea helped elderly patients stand using their remaining physical strength maximally by performing the two assistive functions simultaneously.