Adaptive robust autopilot design of time-varying uncertain ships with disturbances

This paper develops an adaptive robust course controller for time-varying parametric uncertain nonlinear ships with completely unknown time-varying bounded control coefficient and disturbance. The proposed design method does not require any a priori knowledge of the signs of the unknown time-varying control coefficient and the bound of unknown time-varying parameters and disturbance. It is proved theoretically that the designed adaptive robust autopilot of ship steering can guarantee the global uniform ultimate boundedness of all signals of the resulting closed-loop ship course control system. The adaptive robust regulation of the ship´s course is achieved. The effectiveness of the presented autopilot has been demonstrated in simulations.