Switching control approach for the robust practical stabilization of a unicycle-like marine vehicle under non-vanishing perturbations

This paper presents a solution to the robust practical stabilization of a unicycle-like marine vehicle, under non vanishing current-induced perturbations. A hysteresis-based switching control strategy is proposed, rendering the system globally practically stable to a set G around the origin. The control scheme consists of three control laws; the first one is active out of G and drives the system trajectories into G, based on a dipole-like vector field. The other two control laws are active in G and alternately regulate the position and the orientation of the vehicle. The system is shown to be robust, in the sense that the vehicle enters and remains into G even if only a maximum bound of the perturbation is known. The efficacy of the solution is demonstrated through simulation results.