Design Of Wide Speed Domain Dynamic Inverse Control Law For Flying Wing UAV

In recent years,with the continuous development of radar and missile technology as the support of air defense system,the performance requirements of military aircraft all over the world are also increasing.More excellent stealth performance,longer endurance time and greater load loading have become the mainstream trend of military aircraft development.Compared with the traditional layout,the flying wing layout can better meet the above requirements,and has excellent stealth performance,which is convenient to complete reconnaissance,penetration and other combat tasks in high threat environment.Therefore,flying wing layout has become the main layout selection direction of the sixth generation main combat aircraft in the future.However,the flying wing configuration also brings great challenges to flight control,because of its low longitudinal control efficiency,low heading damping,serious control surface torque coupling,and obvious nonlinear characteristics of aerodynamic parameters in a wide speed range.This has also become the core problem affecting the wide application of flying wing layout.In the above problems,the nonlinear characteristics of aerodynamic parameters obviously lead to the failure of the traditional linear control method of adjusting parameters according to a single stable state point in the flight envelope.The torque coupling of the composite control rudder arranged on the wing is serious,which also makes it difficult for the conventional control allocation method to achieve the ideal efficiency.Therefore,based on nonlinear dynamic inverse control,this paper designs a wide speed domain and high reliability flight control system of flying wing UAV,designs an efficient control allocation method based on intelligent algorithm,and carries out simulation verification.The main research contents of this paper are as follows:(1)The nonlinear dynamic model of flying wing UAV is established,and the handling stability characteristics and rudder efficiency characteristics of flying wing UAV at different speed state points are systematically analyzed.The analysis shows that the flying wing UAV has the characteristics of high lift drag ratio,poor longitudinal stability,low longitudinal control efficiency,high rolling stability,weak heading stability,low heading damping,and obvious changes of aerodynamic parameters and rudder efficiency with speed.(2)In view of the obvious nonlinear characteristics of the aerodynamic characteristics of flying wing UAV with the change of flight speed and altitude,the dynamic inverse control method is used to complete the design of the general autonomous flight control law of multiple state points in the wide envelope,which solves the problem that the traditional PID control method needs to design the control parameters independently according to each state point in the envelope,The effects of the two control methods are simulated and verified at multiple state points.(3)Aiming at the problem of high model accuracy in the application of dynamic inverse control method,the idea of incremental dynamic inverse control is introduced to reduce the sensitivity of the controller to model parameters and improve the robustness of the control system to model parameter uncertainty and external disturbances.Through the simulation comparison with the conventional dynamic inverse control method,it is verified that the robustness of the proposed control method is significantly improved.(4)Aiming at the characteristics of flying wing layout with multiple control surfaces,serious control torque coupling and obvious nonlinear characteristics,particle swarm optimization algorithm is used to realize the coordinated control allocation for multiple control surfaces.The Improved Grey Wolf algorithm is introduced to optimize the optimization process of particle swarm optimization algorithm,which improves the operation efficiency of particle swarm optimization algorithm.Compared with traditional control allocation methods such as series chain,it is proved that the allocation accuracy of intelligent allocation algorithm is better,and the state of rudder surface saturation caused by excessive use of a certain stage of rudder surface will not appear,which can effectively solve the problem of efficient coordinated operation of multiple rudders Fault control reconfiguration.Through incremental dynamic inverse control and intelligent algorithm allocation,the high reliability robust control of flying wing UAV in wide speed domain is realized.The robustness and efficiency of the proposed method are verified by simulation analysis.The research results of this paper provide reference for the design and engineering implementation of wide speed domain flight control system of flying wing UAV,and lay a technical foundation for its future development and application.