The Control Of Ship Course And Track Motion Based On Backstepping

As trade between countries around the world continues to increase,surface vessels are used as the main means of transportation.Its performance requirements are further increased.When sailing long distances between the two ports and operating on special occasions,we always hope that the surface vessels can withstand ocean disturbance during navigation and follow the preset course and track signals accurately.Therefore,the research and control of ship course and trajectory is a very valuable subject.The surface vessel is regarded as the controlled object and the backstepping control algorithm is used to design the ship's course and trajectory controller in this paper.The main achievement of this article includes:1.On the basis of the characteristics of the ship's motion and the different emphasis of the research,a mathematical model of the ship's six degrees of freedom is established from the perspective of dynamics,and further simplified into a three-degree-of-freedom model based on its characteristics.At the same time,in order to facilitate the research and analysis of course control,Norrbin nonlinear mathematical model is established.2.Aiming at the problem of uncertain model parameters in the ship course non-linear system,an adaptive backstepping course tracking control algorithm is obtained by adaptively adjusting the parameters in the backstepping algorithm.3.In the course control system,we consider the fact that the input saturation characteristics of the actuator and the uncertainty of the model parameters exist at the same time,the method of combining the auxiliary design system and the adaptive backstepping control algorithm,which is used to design the ship course anti-saturation robust controller.4.A systematic design method for a robust disturbance observer is given.At the same time,the design indexes such as the interference suppression performance,robust stability,and sensitivity performance of the system are considered,and the norm evaluation function of the filter is established.A virtual loop shaping method is used to solve the Q-filter within the H?framework.Then,according to the frequency characteristics of the sea waves suffered by ship course control system,the weighting functions of disturbance and model perturbation are selected,and the performance evaluation function is established.5.For the three-degree-of-freedom full-drive ship trajectory tracking control with unknown time-varying disturbances and actuator input saturation,a trajectory tracking backstepping control algorithm is designed with the disturbance observer and command filter,which can solve the differential explosion problem in the backstepping method,and introduces a filter compensation mechanism.By selecting Lyapunov function,it is proved that the controller can guarantee all signals in the closed-loop system is uniform ultimate bounded.