Design And Simulation Of Adaptive Backstepping Controller For Ship Course

Because the effect of the external environment,such as wind,waves and currents complex instabilities and nonlinearities itself,so nonlinear ship course controller with robust adaptive performance attracts more and more attention.In this thesis,the course control of the ship on the sea was studied on the basis of Backstepping control theory and the main contents were as follows:1.Considering the complex and changeable sea conditions,the mathematical models of environmental disturbances including wind,waves and currents are discussed in this thesis.From the perspective of kinematics and dynamics,this thesis analyzes the dynamic characteristics of ship motion and the hydrodynamic characteristics of the ship,and establishes the equation of mathematical motion of the ship.2.Aiming at the ship course nonlinear control system with uncertain parameters,the ship steer controller is designed based on the theory of backstepping method and the adaptive control algorithm.3.Taking the saturation of system into account,an algorithm based on auxiliary design system is applied.Considering the uncertainties of the ship parameters and disturbances in the nonlinear ship course control,the corresponding ship course controllers are designed.4.Given the above,considering both the interference and the input saturation phenomenon of the system,and combing the nonlinear disturbance observer and the adaptive control algorithm,the controller which has more robustness can be constructed as a disturbance observer directly instead of depending on system model.The algorithms employed in this thesis can ensure the stability of the closed-loop system,and the later two works into account the system's input saturation,further enhance the practicability of the system step by step,and the control effect is good.The simulation in Matlab verified the effectiveness of the algorithm.