A Novel Reconfigurable Closed-Chain Leg Mechanism Based on Phase Difference Adjustment for Multiple Walking Motion of Quadruped Robot

Abstract

The utilization of single degree-of-freedom (DOF) closed-chain mechanisms as leg mechanisms of quadruped robots has been studied because of its advantages, such as a lightweight structure and simplified control resulting from the decreased number of actuators needed for operation. Furthermore, to improve the scalability of these approaches, researchers have investigated the use of reconfigurable structures. Nevertheless, the traditional method that relies on adjusting the length of links presents a substantial challenge in achieving precise production of various trajectories while maintaining the centroid positions of those trajectories. We propose a novel reconfigurable structure that utilizes the phase difference between the crank gears to generate desired trajectories accurately. The proposed mechanism guarantees that the centroid positions of multiple trajectories remain confined inside the specified border. Comparison with conventional reconfigurable mechanisms demonstrates the ability of the proposed mechanism to achieve high trajectory accuracy over multiple trajectories, even in environments with limited centroid position changes. Additionally, a gait stability analysis of a quadruped robot with the proposed leg mechanism in a simulation environment was conducted to verify its suitability.