Asymmetric Robotic Catapults based on the Closed Elastica for Jumping Robot

Abstract

In this paper, we propose new asymmetric robotic catapults based on the closed elastica. The conventional robotic catapults based on the closed elastica the authors developed are the robotic elements for generating impulsive motions by utilizing the snap-through buckling. In a typical closed elastic catapult, the two ends of an elastic strip are fixed to a passive rotational joint and an active rotational joint, respectively. Here, we found that we could obtain higher impulsive motions by adding the range limitation to a passive rotational joint which makes the shape of the elastic strip just before snap-through buckling complicated. The range limitation leads to storing the higher elastic energy for an impulsive motion without changing the actuator of the active joint. We show the results of theoretical analysis and numerical simulations which support the effectiveness of the proposed robotic catapults. We also show that the jumping robot with the asymmetric robotic catapult achieves high performance.