Backstepping Based Fuzzy Adaptive Control Of Ship Course

Ship motion control is the core of ship automation, which is directly related to the safety, maneuverability and economy. However, the ship motion itself has the characteristics of nonlinearity and uncertainty. Designing the course controller based on the nonlinear ship motion is important for the theory value and practical significance. According to the characteristics of ship course system, this article studies the adaptive fuzzy control of nonlinear ship course, based on the Backstepping algorithm and fuzzy adaptive control.Firstly, combined with the Backstepping algorithm, this paper designs the controller using the ship course control as the research object. And then based on the Backstepping, this article designs a nonlinear Backstepping adaptive controller for the ship course system with parameter uncertainty. The simulations is analyzed in the condition of non-disturbance and disturbance, and the results show that adaptive course controller based on the Backstepping can be better completed the track.Secondly, the unknown nonlinear functions are contained in the ship course control system. Based on the feedback linearization techniques and the theory of Lyapunov, an indirect adaptive fuzzy control strategy which can ensure the stability of the ship course system is put forward in this paper using the T-S fuzzy system as the online approximation. And then combined the adaptive fuzzy control with the Backstepping algorithm, this paper proposes an adaptive fuzzy control method based on the Backstepping with the theory of Lyapunov. The Lyapunov can ensure the stability of the closed-loop system and the convergence of the adaptive parameters. And the simulation results show that this method is effectiveness and superiority.Finally, in view of the ship motion model, this paper adds the learning error into the original adaptive fuzzy control law based on the L2theory and puts forward to a direct adaptive fuzzy control of the ship course based on the learning error. The simulation results show that this method can achieve better control effect than before.