Fuzzy adaptive control for ship steering autopilot based on backstepping technique

In allusion to the nonlinear Norbin ship model, a new fuzzy adaptive control algorithm for ship steering autopilot based on backstepping technique and the approximation capability of the fuzzy system constructed by radial basis function(RBF) was put forward, all parameters of the fuzzy system were on-line tuned by Taylor linearization technique. A robust controller was employed to dispel the effect of the approximation error introduced by the fuzzy estimation system. The adaptation laws of the control system were derived based on Lyapunov function. Simulation result shows that the closed-loop control system of steering autopilot is asymptoticalry stable, the error of the output trajectory of ship model and a desired trajectory is zero. The proposed algorithm has better adaptive ability than traditional PID control algorithm.