The Study Of Formation Maintain Control Methods Of Unmanned Air Vehicle During Aerial Refueling

Unmanned aerial vehicles are playing a very important role in modern warfare, aerial refueling technology can increase the flight range, cruising duration and payload of UAVs. The direction of future development of the UAVs is equipped autonomous aerial refueling capability, this thesis has studied the formation flight control problem of receiver aircraft during autonomous aerial refueling.First of all, according to the relevant knowledge of flight mechanics and aerodynamics, this paper did a deep analysis of the changes of mass and was equivalent to the disturbances of forces and moments to suppress the influences of fuel transferred to the unmanned aerial vehicles, and the nonlinear model of unmanned aerial vehicles was built. In order to further analysis the characteristics of the unmanned aerial vehicles, a simple fuel tank model and three different refueling cases were established to simulate the process of refueling, analyzed the fuel transport’s influences on natural characteristics of the model. These could set a solid foundation for the next step of the control law design.Secondly, based on the Biot-Savart law, the problem of the aerodynamic coupling of formation flight was studied. Assume that the tanker aircraft was replaced by horseshoe vortex model approximately and the receiver aircraft was replaced by ellipsoid wing to analyze the change of the receiver aircraft’s forces and moments of the receiver aircraft during the formation flight.Thirdly, Used the classic control methods to design the control law, the maintain control system structure of the formation flight during aerial refueling was built and completed the design of altitude hold controller, heading hold controller, lateral deviation controller and speed hold controller. And the formation flight control of unmanned aerial vehicles based on neural network dynamic inversion was studied. Based on the nonlinear formation model, the inner loop of the system of formation flight control was designed used the method of dynamic inversion. The neural network was used to compensate the inversion error included by the inaccuracy of the system model.Finally, the simulation model of the maintain control system is established in the numerical environment in MATLAB. The simulation results show that this method applied to formation flight maintain control system is feasible and effective.