Muscle Synergy Analysis Under Fast Sit-to-stand Assist : A Preliminary Study

With the recent advance in robot technologies and the aging of society, a variety of sit-to-stand (StS) assisting systems have been proposed. In this research, we preliminary measured the performance of the chair assistance that enables StS motions faster movements than conventional assistive chairs. The chair has two actuators for sliding forward and lifting up the seat, and has enough power and speed for enabling fast StS. We analyzed the users' coordination of muscle activities in terms of the muscle synergy through the experiments. The results show that the users can perform natural sit-to-stand in which muscle synergy patterns similar to those without assists appear. It suggests that the chair device potentially enables natural and fast StS that healthy young people commonly perform.