Robust Control For Underwater High Speed Vehicle Based On High Gain Observer

Due to the application of supercavitation drag reduction technology,the speed of underwater vehicles has been greatly improved.However,the complexity of the environment of the underwater high speed vehicle and the constant change of the cavitation surrounding the vehicle bring great difficulties to the maneuvering control of the vehicle.It is of great theoretical and practical significance to design an effective observer and robust controller for the disturbance of external noise,model uncertainty and unmeasurable state parameters of underwater high speed vehicles.Therefore,based on the longitudinal plane modeling of underwater high speed vehicle,the design method of observer and controller is studied and simulated.The specific contents are as follows:Firstly,the longitudinal plane motion of underwater high speed vehicle is modeled mathematically.After the stable navigation mode and coordinate system of the vehicle are selected,the force and torque of the vehicle are analyzed.On this basis,the longitudinal plane motion of the underwater high speed vehicle is modeled mathematically,and the open-loop simulation analysis of the model is carried out.Secondly,the extended high gain observer is designed based on the theory of high gain observer for the unmeasurable state parameters of underwater high speed vehicle and the uncertainty of the model.The observer estimates the unmeasured state parameters and the uncertainties in the system.And the output feedback controller with high gain observer is designed based on pole assignment feedback control algorithm.Simulation results show that the output feedback control system with high gain observer can achieve different performance of state feedback control system under different parameters.Then,We analyze the peak phenomenon of high gain observer and propose the anti-saturation control method to solve the peak phenomenon.Thirdly,the H2/H∞ state feedback robust controller is designed to deal with the strong nonlinear planing force and the interference of external noises in the longitudinal plane motion of the underwater high speed vehicle.By analyzing the planing force mechanism of the vehicle,we transformed the vehicle model into LPV model.Combining H2 control and H∞ control,we design H2/H∞ state feedback robust controller.The performance of the controller was verified by simulation analysis of the nominal model,interference model and parameter uncertainty model.Finally,we complete the robust control of underwater high speed vehicle output feedback.In order to solve the problems such as the interference of external noise and unmeasurable parameters in the longitudinal plane motion of underwater high speed vehicle.Based on the LPV model of the vehicle,the output feedback robust controller and the multi-objective constrained robust variable gain output feedback controller based on the high gain observer are designed respectively.The performance of the two output feedback controllers is analyzed by simulation.