Abstract
At this laboratory we have been studying and producing comfort-chair-type power assisted chairs using a pneumatic system. The power assisted chairs were evaluated by the questionnaires of the subjects before. In order to get quantitative design guideline, this study aims to evaluate assist-effect by dynamic parameter. In particular the forces exerting human body under stand-up and sit-down motions were measured by load sensors, and the joint angles were measured by motion capture techniques using digital video camera. The torques which works at knee joint and hip joint were calculated based on a human body assuming a 3-link model.