Abstract
This paper describes a locomotion method of a snake-like robot with passive wheels based on a stabilizing control theory for nonlinear systems. The advantage of this method is that the locomotion can be realized only by a state feedback control law, while many reported methods require some reference trajectory such as the serpenoid curve or are realized not only by a locomotion control, but also by a posture control to avoid singular postures. The proposed method evaluates the friction force of passive wheels in the quadratic-like cost function, so that the efficiency with respect to the input can be improved. The state-dependent Riccati equation technique is utilized to realize this method and it permits us to tune the system performance like an optimal control case. The projection method, one of the nice modeling techniques, is utilized to derive both the plant and the friction model. The effectiveness of the proposed method is verified through numerical simulations and experiments.