Docking Control Method For Autonomous Aerial Refueling For Unmanned Aerial Vehicles

With the development of unmanned aerial vehicle technology,autonomous aerial refueling has become an important capability of UAVs.Realizing the autonomous aerial refueling technology can effectively improve the range and time of UAVs and expand the range of use.In the process of autonomous aerial refueling,the docking segment is the most risky and most important stage.In the presence of various external disturbances,the requirements for control accuracy and safety of the docking section are very high,which directly affects the success or failure of docking equipment.This paper mainly focuses on the control issues of autonomous aerial refueling of UAVs.The main contents are as follows:Firstly,the autonomous aerial refueling system of UAV is modeled,and the related coordinate system,aerodynamic model and atmospheric model are introduced.The sixdegree-of-freedom dynamic model of UAV is established.Then,taking into account the actual situation of aerial refueling of UAVs,a model of atmospheric turbulence and a movement model of refueling drogue were built.This is the basic work of the full text and provides a mathematical model for the design of the following control system.Secondly,a state observer-based docking tracking control system was designed using LQR method.The relative position information is calculated by the reference trajectory generator,and a smooth trajectory is generated in real time for the tracking of the UAV.The state observer is used to estimate the reference state and control of the UAV.The LQR controller is used to control the UAV tracking drogue and complete the docking.In order to improve the control accuracy,an integral LQR-PI controller was designed on the basis of the above,and the two controllers were simulated,and their tracking accuracy and system performance were analyzed and compared.Thirdly,aiming at various uncertainties in the actual docking process,a docking control system based on adaptive sliding mode control was designed to enhance the system's anti-jamming capability.The attitude loop controller of the UAV was designed using a layered structure using a first-order integral sliding mode and a second-order terminal sliding mode.Through simulation analysis,the control effect and stability of the designed system are verified.Finally,a comprehensive simulation of the designed autonomous air refueling docking control system was carried out.Under the interference of three different degrees of atmospheric turbulence,through simulation verification,the tracking performance and docking feasibility of each controller in the docking task were fully evaluated,and the simulation results were compared and analyzed.