Development of a Three-Layer Fabric Mechanism for a Passive-Type Assistive Suit

• Published in: Journal of robotics and mechatronics 2022-12, Vol.34 (6), p.1348-1360
• Main Authors: Wan, Chi Lok, Ishioka, Toshifumi, Kanda, Chiaki, Osawa, Keisuke, Kodama, Kenji, Tanaka, Eiichiro
• Format: Article
• Language: English
• Subjects: Fatigue; Muscles; Perception; Rubber; Workers
• ISSN: 0915-3942; 1883-8049
• DOI: 10.20965/jrm.2022.p1348

This paper proposes a three-layer elastic cloth fabric mechanism for an assistive suit with adjustable structure (based on a two-layer non-adjustable structure) to achieve different assistive force profiles. This increases the assistive force on the lower-back muscle group and alleviates the undesired pre-tension that acts on a user when the rubber belt located on the back is pulled to provide a higher assistive force. With the lower pre-tension, users would not encounter body fatigue as rapidly as in the past. The adjustable feature enables the structure to provide a force that increases gradually to a high level over a short distance without pre-tension. An experiment involving the measurement of muscle activities is conducted to evaluate the variation in assistive force in the lower back by comparing the three-layer suit to the two-layer non-adjustable suit. The experimental results show that the new three-layer structure successfully assists without pre-tension in the lower-back muscle group similar to the two-layer structure with pre-tension. A simple questionnaire is also administered to collect feedback from participants on the differences between the three-layer suit and two-layer suit in terms of wearing perception. Over half of the participants reported that the perception of pre-tension in the three-layer suit is lower than that in the two-layer suit.