Development of a gripper for power assist suits with linkage and ratchet mechanisms

Abstract

The L-shaped gripper commonly used in power assist suits has the problem of not being able to stably hold arbitrarily shaped objects. To solve this problem, we developed a gripper with a wire-driven ratchet mechanism. However, we could not confirm its effectiveness in reducing the burden on the hands and arms for irregularly shaped objects such as rice bags. This is because the mechanism using a wire did not work as expected due to friction between the wire and the wire guide. Therefore, in this study, we solved these problems by developing a gripper with a link-driven ratchet mechanism, which does not use a wire. We conducted experiments to compare the proposed gripper with our previous gripper by measuring the surface EMG of the wearer's arms when lifting objects of various shapes.