Tracking control of surface vessels via fault-tolerant adaptive backstepping interval type-2 fuzzy control

This paper focuses on tracking control of fully actuated surface vessels along a desired trajectory in the presence of time-varying hydrodynamic disturbances. The combination of backstepping control and approximation-based adaptive technique allows the proposed controller to accommodate certain faults in the plant and the controller itself, and to handle time-varying hydrodynamic disturbances without explicit knowledge about the disturbance model. Through backstepping and Lyapunov synthesis, a state feedback fault-tolerant adaptive backstepping interval type-2 fuzzy logic controller is introduced, with the option of high-gain observer for output feedback control. The stability of the closed-loop systems is explored where sufficient condition for guaranteeing global asymptotic convergence of the tracking errors in state feedback control is proposed, whereas semiglobal uniform boundedness of the closed-loop signals in output feedback control is guaranteed. Simulation studies with a container ship are carried out. The proposed technique is found to be effective and robust.