Design of shock mitigation mechanism using momentum exchange and avoidance of impact transmission inspired by break-fall in Judo

Abstract

Shock mitigation mechanism is important because mechanical parts can be broken by high acceleration from impact. Springs and dampers are often used, however, the impact is transmitted to the body. To reduce the body velocity for small impact, the mechanism exchanging the momentum from the body to damper-mass has been proposed. On the other hand, mechanical singularity is effective way to avoid the impact transmission. This paper proposes a 1-DOF shock mitigation mechanism inspired by break-fall in Judo. The mechanism exchanges momentum without control system and avoids impact transmission by sequential singular configurations. The first singularity occurs when the center-rod lands, and the second occurs when a weight hits ground. Hitting ground also releases energy by the same way as break-fall in Judo. Through the experiment using a high-speed camera, momentum exchange and avoidance of impact transmission are evaluated.