Controllers based on an invariant manifold approach for stabilizing a nonholonomic mobile robot

A system with nonholonomic constraints attracts its attention from the viewpoint of control theory because no conventional control can be applied directly to such a system. Since it cannot be stabilized by a static continuous feedback with constant gains, there are several control methods by using a chained form up to now. In this paper, a four-wheeled mobile robot which is an underactuated system with two inputs is considered as a controlled object. Then, the switching and non-switching control methods based on an invariant manifold theory are proposed for stabilizing it, where a chained form model is assumed to be used as a canonical model. The effectiveness of the proposed method is demonstrated through simulations for a four-wheeled mobile robot.