A novel adaptive fuzzy autopilot design based on DSC

This paper develops an adaptive fuzzy course controller with rudder dynamics. The ship model is described by a third order nonlinear model with unknown parameters and unknown virtual control gain function. The Takagi-Sugeno (T-S) type fuzzy systems are used to approximate unknown system functions and a systematic design procedure is developed by combining dynamic surface control (DSC) technique. With only one learning parameter and reduced computation load, the proposed algorithm can avoid both problem of "explosion of complexity" in the conventional backstepping method and singularity problem. In addition, the boundedness stability of the closed-loop system is guaranteed and tracking error can be made arbitrary small. The effectiveness of the presented autopilot has been demonstrated in the simulation.