Research On Longitudinal Motion Control Of Supercavitating Vehicles Based On Strong Tracking Filter Algorithm

Supercavitation technology is the most effective method to reduce the drag and improve the speed of underwater vehicles.The technology uses natural or artificial ventilation to generate cavitation to wrap around the vehicle,greatly reducing the wet area of the underwater vehicle,and achieving the goal of drag reduction.However,the supercavitating vehicle loses the buoyancy effect of water,because it is wrapped by the cavitation mostly.The dynamic characteristics of the supercavitating vehicle are more complex than that of the conventional underwater vehicle,which brings great challenges to the dynamic modeling and stability control of the supercavitating vehicle.Based on the theoretical research and experimental research,the longitudinal theoretical model of the supercavitating vehicle is improved in this paper.A control algorithm based on strong tracking filter is designed to solve the problem of the system control precision decreasing and the vehicle motion instability caused by noise interference.The main research contents of this paper are as follows:Firstly,the forces and corresponding torques in the longitudinal plane of the supercavitating vehicle are analyzed in the body coordinate system.On this basis,the longitudinal theoretical model of the supercavitating vehicle is established,and the dynamic analysis is carried out.Secondly,the control algorithm of the longitudinal motion of the vehicle is designed for the longitudinal theoretical model of the supercavitating vehicle.Firstly,a linear state feedback controller is designed for the longitudinal linear model of the supercavitating vehicle without sliding force,and the simulation results are verified.Then,considering the influence of parameter perturbation on the system stability,the system absolute stable state feedback control algorithm which is based on the circle criterion theorem is designed for the longitudinal nonlinear model with sliding force.Thirdly,the water tunnel experiment is carried out to get the actual noise and improve the longitudinal theoretical model of the supercavitating vehicle.The influence of the actual noise on the system control precision and the longitudinal motion stability of the vehicle is analyzed by simulation,which lays a foundation for further research on the stability control of the supercavitating vehicle under the interference of the actual noise.Finally,the state feedback control algorithm based on strong tracking filter is designed.The principle and implementation of extended kalman filter and strong tracking filter are studied.A state feedback controller based on the improved strong tracking filter is designed,and the simulation results are verified.