Proposal of Non-Rotating Joint Drive Type Power Assist Suit for Lower Limbs Considering Squat Lifting

Abstract

Lower back pain is a major health concern worldwide. One cause of lower back pain is the burden on the lumbar region caused by handling heavy objects. The Ministry of Health, Labour and Welfare in Japan has recommended “squat lifting” to reduce this burden. However, this technique, which supports a large force on the lower limbs, is not very popular. Therefore, we aim to develop a power assist suit for squat lifting and propose herein a gastrocnemius-reinforcing mechanism. We also discuss the joint torque estimation from a motion analysis of squat lifting to construct a prototype. Finally, we describe the performance of the prototype when mounted on a human body. We found that when using the prototype assist suit, the %MVC (maximum voluntary contraction) of the gastrocnemius while performing squat lifting reduced by 48% compared to the value obtained without using the suit.