Research On Accurate Control Of UAV In Aerial Refueling Process

Aerial refueling will extend the range,shorten the response times,and extend the loiter time of UAVs.This thesis has studied the guidance and control problem of the unmanned receiver aircraft during rendezvous phases in the autonomous aerial refueling.First of all,the two control structures of an unmanned receiver accurate tracking system during autonomous aerial refueling are analyzed.What’s more,the unmanned receiver aircraft six degrees of freedom model,atmospheric turbulence model and vortex wake model have been established.It laid the foundation for the follow-up study.Secondly,based on the idea of separate design of guidance and control loop,the flight control law is designed by using backstepping method based on radial basis function neural network.With interference involved,simulation results are compared with neural network in the control system or not.Simulation results show that,in the closed-loop system,precise attitude control is accomplished in spite of the uncertainties and external disturbances in the system.The guidance system is designed by L1 guidance algorithm.Thirdly,in order to further improve the performance of unmanned receiver aircraft tracking control,adopting the integrated guidance and control method to design unmanned receiver aircraft flight control system.LOS model of unmanned receiver aircraft tracking tanker has been established,and the integrated control strategy is proposed,nonlinear unmanned receiver aircraft model is improved with feedback linearization.On this basis,The system is designed based on the adaptive neural network feedback.Finally,the simulation system of the receiver refueled aircraft accurate tracking system during arial refueling process is set up.Simulations of the controllers of the two designs were carried out under the condition of adding two kinds of air disturbances respectively in the simulation,the results show that the accurate tracking control system of unmanned receiver aircraft based on two different design methods can accurately track the tanker.but the control system has better control performance by using the integrated guidance and control design structure.