Latissimus-dorsi-inspired wire mechanism for improving energy efficiency of quadruped robot locomotion

A spine, flexible structure in the trunk, improves the locomotion energy efficiency of the quadruped robot. However, improving energy efficiency remains a significant challenge for quadruped robots seeking long-duration operations. This study introduces a wire mechanism that converts active spine flexion into the forelimb propulsive motion, improving energy efficiency during locomotion through spine flexion-extension shape change. Quasi-static force simulations and static force measurements with a developed robot confirm that the proposed mechanism increases the force generated at the forelimb foot. Furthermore, robot-running experiments demonstrates that the robot with the proposed mechanism runs more energy efficiently. These results support the proposed mechanism's effectiveness in improving energy efficiency in locomotion with spine flexion-extension shape change.