Analysis of the Physical Capabilities of Individual Elderly People using Muscle Synergy and a Standing Assistance Robot based on this Analysis

The aim of this paper is to realize a robot that supports standing motion for elderly people with low care needs, using the person's residual physical strength to prevent further decline in their physical strength. To realize this objective, the two key ideas proposed in this paper are as follows. The first idea is to identify the multiple basic movements that make up the standing motion of the elderly through a muscle synergy analysis of the standing motion of the elderly. This makes it possible to design standing assistance procedures according to the physical condition of the elderly person, as the basic motions can be matched to the stability margin range, which varies from one elderly person to another. The second idea proposes standing assistance procedures that allow the voluntary standing motion of the elderly to demonstrate their remaining physical abilities in standing motions. Even if an elderly person performs a standing assistance procedure that differs from the designed standing assistance procedure, our standing assistance robot allows the posture of the elderly person if it is within the stability margin of the individual elderly person, and only gives force assistance to the elderly person if the posture is not within the stability margin. This leads to safety and voluntary movement during standing motion. The above proposed method was implemented in our standing assistance robot prototype, and through experiments with subjects, we confirmed that it brought out the subject's remaining physical strength in standing assistance procedures.