Study of the Relationship Between Sit-to-Stand Activity and Seat Orientation

Sit-to-stand (STS) activity from a chair is an important motion in daily life. However, some elderly or physically disabled people experience difficulty in standing because of a deterioration in physical function. Although nursing is necessary for such people, the burden on nursing staff is heavy, especially in the toilet. There are some commercial products to assist with STS activity in toilets. However, these products are problematic because they are large in size and not controlled according to the residual ability of the user. Therefore, to solve these problems, we would like to develop a new device to help STS activity in toilets by reconsidering the ascent/descent mechanism of the seat and actuator. Moreover, no optimal seat movement were shown, although there were some researches about seat orientation during the STS activity [Kawagoe 2000, Takahashi 2012]. In this paper, we investigated the relationship between ease of STS activity and seat orientation during STS activity to improve the design of the seat mechanism.