Development of Sit-to-Stand Chair

Abstract

Elderly people and persons with disabilities are likey to be obstructed activities in daily life by deteriorating of sit-to-stand ability. The population of elderly people are increasing rapidly in Japan, and the support of sit-to-stand is hard work for caregivers, who are likely suffering back pain. The purpose of this study is to develop a sit-to-stand assist chair, which assists sit-to-stand movement by lifting a seat. In this report, we focus on the trajectory of a buttock in sit-to-stand, and report results of experiments on three foot height conditions. The buttock's trajectories had a S shape on the high foot height, which was the hardest condition, and was changed to an arc shape on the low foot height, which was the easiest in this study. In the case that the buttock's trajectory gets close to the arc shape, the hardness of the standing motion might be reduced. The velocity of buttock movement varies with the person's height.