Simulation Studies on Adaptive Nonlinear Control of Ship Motion Course

The maneuvers of the ship with the characteristics of the rudder are described by the unmatched uncertain nonlinear model with unknown virtual control coefficient. A nonlinear adaptive control algorithm combining adaptive backstepping algorithm with Nussbaum gain technique is proposed for ship course keeping steering without a prior knowledge about virtual control coefficient. By means of Lyapunov function, it is theoretically proven that the proposed controller makes all signals of the resulting closed-loop adaptive system uniformly bounded, and set heading is kept by the actual heading output of the controlled uncertain ship motion nonlinear system. The results of simulation show that the designed controller can be properly adopted to the ship course keeping with good effectiveness.