Preferred Pressure Distribution and Shift Ratings of Comfort on Auto Bed

Abstract

The main aim of the study is to investigate the preferred pressure distribution and shift of comfort ratings on auto bed, which user can adjust height in 8 parts of mattress by controller. The body pressure distributions were measured under two states (at the posture of lying on his/her back, side and face). One was measured in the lying state on the common flat mattress. The other was done after subjects adjusted height of 8 parts to keep comfortable feeling. The results of the study were following. All of three postures had the highest value to the body pressure ratio of the hip. Particularly, when he/she was lying on his/her back, more than 40% of the total body pressure ratio was concentrated on the hip. Also, in each posture, most subjects feel comfortable when the heights of head and legs are higher than those of the other part. In the posture of lying on his/her back, subjects feel comfortable when the heights of head, lumber and thighs region have been raised to form the body with W shape. In the posture of lying on his/her face down, subjects feel comfortable when the heights of head and legs region have been raised to form the body with U shape. The significant relation between change in rating of comfort and change in body pressure ratio was found within each posture, that is, the body pressure distribution may have affect on comfort rating. Also, significant difference was observed between the initial state and the final state in the subjective evaluation.