Path Tracking Control Of Unmanned Surface Vehicles Based On Feedback-Sliding Mode Strategy

In order to improve the autonomy and accuracy of Unmanned Surface Vehicle(USV)in navigation,aiming at the problem of path tracking control in motion control of USV,based on feedback linearization technology and sliding mode control technology,combined with the advantages of neural network control technology and adaptive robust technology,a hybrid path tracking controller for USV is proposed,The simulation experiment platform of path tracking control for USV is constructed by Visual Studio,and the related simulation experiments are carried out to verify the proposed control method.The specific research contents are as follows:1.The mathematic model of the path tracking control system of USV is established.The mathematic model of USV is the basis of the design of the path tracking controller.This paper summarizes the previous research results and establishes the path tracking mathematic model of USV,including the linear path tracking model and curve path tracking model of USV,By introducing Serret-Frenet coordinate system and polar coordinate system,the path tracking mathematical models of USV in Serret-Frenet coordinate system and polar coordinate system are established,which lays a foundation for the design of the controller behind.2.Aiming at the problem of path tracking for a class of USV with uncertain external disturbance,a feedback-sliding mode neural network controller based on input-output linearization is designed by using the approximation ability of RBF neural network system to approximate the unknown external disturbance in the model and combining input-output linearization technology and sliding mode control technology.The simulation results show that the designed controller can effectively suppress the inherent chattering phenomenon of conventional sliding mode,track the set path quickly and accurately,and show strong robustness.3.In view of the random disturbance and the uncertainty of model parameters in the path tracking control system of USV,the adaptive robust technique is applied to solve the adverse effects of the uncertain model parameters and uncertain external disturbances on the control effect.On the one hand,the adaptive technique is used to estimate the uncertain model parameters online,so as to minimize the error with the actual parameters.On the other hand,robust control technology is used to weaken the external interference.Combined with input-output linearization technology and sliding mode control technology,a feedback-sliding mode adaptive robust controller based on input-output linearization is designed in polar coordinates.Theoretical and simulation studies show that the designed controller can guarantee stable tracking and effectively suppress the inherent chattering of conventional sliding mode,and has strong robustness,and can estimate the parameters online,thus improving the path tracking accuracy under uncertain factors.