Vision/GPS Based Docking Control For UAV Aerial Refueling

Unmanned aerial vehicles have been widely used in modern military war to perform different missions from reconnaissance,intelligence acquisition,to combat missions.Autonomous aerial refueling could supply fuel to UAV during the flight of UAV.It can increase the combat radius,payload and endurance of UAVs.This paper has studied the multi-sensor integrated navigation and docking control problem of the UAV during autonomous aerial refueling.First of all,the reference frames and the unmanned receiver aircraft six degrees of freedom model have been established.In order to precisely simulate the process of autonomous aerial refueling docking phase,the atmospheric turbulence model,vortex wake model and the refueling drogue model were established.Secondly,the multi-sensor navigation system of autonomous aerial refueling has been designed.In order to obtain the accurate relative position between the UAV and the refueling drogue,a vision/GPS based navigation system was proposed.The GPS and machine vision model have been introduced.A linear interpolation method and an extended Kalman filter based sensor fusion method were proposed to integrate the measurements of GPS and machine vision system.The simulation results shows that the extended Kalman filter based sensor fusion system can obtain high accuracy navigation information.Thirdly,the unmanned receiver tracking and docking control system based on L1 adaptive dynamic inversion method has been designed.The L1 adaptive control system was designed to compensate the inversion error caused by turbulence.The results indicate that the L1 adaptive compensated system can improve the robustness of the dynamic inversion based control system.Finally,the vision/GPS based docking control simulation system of autonomous aerial refueling has been established to test the effectiveness of the designed navigation system and control system.The simulation results indicate that the designed vision/GPS based docking control system could restrict the effect of the disturbance and realize the accurate docking of the drogue and unmanned receiver.