Research On Technology Of Small UAV Based On Dynamic Net Recovery

Dynamic net recovery landing for Unmanned Aerial Vehicle(UAV) is an ideal assigned spot recovery method, and this technique is especially suitable for UAV landing on moving aircraft carriers. The problem, how to guide the UAV to the recovery net with reasonable flight attitude and speed, is the key issue of this paper's study. In order to solve this problem, this paper designs a rational recovery trajectory together with guidance and control laws with high accuracy and strong robustness, according to the characteristics of the moving aircraft carrier.Firstly, the paper build aircraft carrier motion model, and then quantitatively analyzes how carrier's navigation and disturbed motion influence the ideal recovery spot. In addition,after analyzing some performance of UAV, the paper designs the typical working point and range of maneuver flying capability, which are the theoretical foundations for recovery trajectory together with guidance and control law, based on UAV six degree of freedom nonlinear motion model.Secondly, Drawing on the mechanism of carrier based aircraft landing, combined with the characteristics of the sample UAV, the paper designs a feasible net recycle plan which contains state adjustment period, proportional guidance period and carrier motion compensation period. The thesis puts forward a new guidance law based on UAV position varying rate, by using proportional guidance. This new guidance law can weaken the sensitivity of the carrier motion to the change of UAV parameters, satisfied the rapid and accurate requirements of net recovery of sample UAV.Thirdly, based on the RSLQR-L1 theory, this paper designs an altitude controller with H?and trajectory tracking controlers with ? and ?.Which satisfies the demands of strong robustness and high control precision. To solve the influences of aircraft carrier's plunging motion recovery precision, the paper designs motion compensation network for UAV control system. The specific network can improve tracking precision of the UAV and achieve high performance of dynamic response.In the end, the paper builds simulation environment for six degree of freedom nonlinear model and aircraft carrier model. To verify the influences of net recovery, the paper take the circumstance of UAV model's uncertainties, wind disturbance, aircraft carrier's plunging motion and sailing speed into consideration. The simulation results indicate that the designed trajectory, guidance law and control law can realize net recovery quickly, stably and accurately.