Semi-endoskeleton-type waist assist AB-wear suit equipped with compressive force reduction mechanism

Abstract

In recent years in Japan, over half of all workers suffered from lower back pain. This has become a social problem that needs to be addressed. To reduce its occurrence, we developed a flexible, high-output waist assist suit called “AB-Wear” in a previous study. The AB-Wear suit can assist human motion and reduce muscular fatigue of the waist. However, the assistive forces of the device generate compressive forces on the backbone, which have adverse effects on the body. Hence, in this study, we propose an exoskeleton-type AB-Wear equipped with a compressive force reduction mechanism, called “semi-endoskeleton-type AB-Wear”. This device has a reduction mechanism similar to a flexible flat spring behind the upper body. Because of this structure, this device can generate an effective assistive force. First, we explain the difference between the semi-endoskeleton-type AB-Wear and the previous device. Then, we model the semi-endoskeleton-type AB-Wear because the model is used for its operation. Moreover, its effectiveness is confirmed using musculoskeletal simulation. Finally it is evaluated by measuring surface electromyography (EMG) on a subject's body to confirm its effectiveness with a real body. The EMGs of the wearer with and without the suit are compared. The usefulness of the AB-Wear is confirmed by simulation and experiment.