Full-state regulation of underactuated unmanned surface vessels via finite-time disturbance observers

This article investigates a full-state regulation control problem for underactuated unmanned surface vessels (USVs) subject to external environmental disturbances. First, by introducing a state rotation transformation, the primary tracking error is reduced to a new translation-rotation cascade system. Then, a backstepping technique method based on Lyapunov function is suggested to stabilize the new system. The problem of external environmental disturbances is compensated by a finite-time disturbance observer (FTDO). It is demonstrated that the designed controller has the ability to guarantee the desired full-state regulation with the external environmental disturbances. Simulation examples are implemented to illustrate the effectiveness of the designed control strategy.