Transleg: A wire-driven leg-wheel robot with a compliant spine

Abstract

A novel leg-wheel robot, Transleg, is proposed in this paper. Differing from the existing leg-wheel robots, Transleg is driven by wire, so the transmission mechanism is simple and the weight is reduced. Transleg adopts a transformable leg-wheel mechanism which has two degrees of freedom in the legged mode and one degree of freedom in the wheeled mode. The motions in and switching between the two modes are achieved by the same actuators. That is to say only two actuators are needed in one leg-wheel mechanism. The spine contributes significantly to the motion of the quadrupeds, so a compliant spine mechanism is designed for Transleg, which is actuated by two actuators and can bend in yaw and pitch directions. The leg-wheel and spine mechanisms and their kinematic analysis are described in this paper. To verify the feasibility of the leg-wheel mechanisms, the motions of Transleg without spine bending in legged and wheeled modes and switching between the two modes are simulated. Experiments on the motion of the prototype of the leg-wheel and spine mechanisms are also performed to validate the effectiveness of the two proposed mechanisms.