Adaptive Nonlinear Design of Autopilot for Ship Course Tracking

An adaptive nonlinear control algorithm combined with an adaptive backstepping algorithm using the Nussbaum gain technique is proposed for ship course tracking steering,which takes into account rudder characteristics and parameter uncertainty.With the proposed algorithm,a ship course-tracking autopilot is designed without any a priori knowledge about virtual control coefficient.Based on the Lyapunov function,it is proved in theory that the controller makes all signals in the nonlinear system of unmacthed uncertain ship motion uniformly bounded,and the desired reference course is asymptotically tracked by the ship's actual heading.Performance is demonstrated in a series of simulation studied.