Design of a Standing Posture Assist Suit with a Drum-Type Mechanical Brake

Abstract

Orchard farmers often maintain a standing posture for long periods of time when growing and harvesting fruit. Japanese farmers are aging. Prolonged standing posture puts strain on their knees and hips. In this paper, we describe a design of a standing posture assist suit that requires no power supply using a drum-type mechanical brake (DTMB). This assist suit does not use batteries or motors, but only passive mechanical elements. When the user’s knees are bent after moving down a lever of the assist suit, the assist suit’s knee joints are fixed by the DTMBs to support the user’s body. After that, even if the user does not continue to depress the lever, the knee joints remain fixed by the DTMBs while the user’s body is supported by the assist suit. Fixation of the knee joints are released when the knees are extended. The method to design the DTMB including an analysis of the activation angle of the DTMB is also explained. An experiment using the DTMB developed based on the design method was conducted to compare the theoretical actuation angle with the experimental results. The experimental results were approximately the same as the theoretical value.