An Novel Model Switching Course Control for Unmanned Surface Vehicle With Modeling Error and External Disturbance

This paper investigates the course control problem for an unmanned surface vehicle in the presence of modeling error and external disturbance. When the unmanned surface vehicle sails at different speeds, the height of the bow lift, that is, the pitch angle, is different, and the parameters of the model will change greatly at this time. This paper firstly divides the driving state of the unmanned surface vehicle into low-speed and high-speed states according to the Froude coefficient, and then obtains the model parameters in different driving states according to the method of system identification. Then, an innovative model switching course control strategy with strong robustness for unmanned surface vehicle based on two-stage time-varying sliding mode method is proposed. The two-stage time-varying sliding mode method can guarantee the global robustness of the whole controlled system. In order to further improve the steady-state accuracy of the system, the time-varying integral sliding mode method is adopted in the second stage sliding mode control. Numerical simulations validate the effectiveness and robustness of the proposed control approach.