A New Lizard-Inspired Robot With S-Shaped Lateral Body Motions

This article presents a new lizard-inspired robot that can maintain its direction of movement via S-shaped lateral body motions during its high-speed bipedal running. For this purpose, a dynamic model and a control scheme for the proposed robot were derived to simulate the S-shaped lateral body motions of a real lizard. Based on simulations using the dynamic model with the proposed control scheme, a prototype of lizard-inspired robot was built to reproduce a bipedal running gait as well as the lateral body motions of a real lizard. The simple robot body consisted of three links connected by two rotational joints and its hind legs were optimally designed upon a four-bar linkage combined with an ankle mechanism. The experimental tests using the proposed robot were performed by confining its motion in the horizontal plane, which demonstrated that the proposed robot can successfully maintain its direction of movement via the S-shaped lateral motion adjusted by the yaw angle of its posterior body during its bipedal running gait similar to the gait of a real lizard.