| Flight control system of fixed-wing aircrafts often meets various problems such as the uncertainties of aerodynamic coefficients,external disturbances and time lags,particularly when it flies at high angle of attack.Therefore,this thesis takes public data F-16 as the research object,designing two controllers with anti-disturbance capability and conduct flight simulated experiment,which achieves the stability and robustness of the system.The main research contents are as the following:The conventional Nonlinear Dynamic Inverse（NDI）controller can be easily influ-enced by unknown disturbances and aerodynamic uncertainties casing poor flight quality of the vehicle.Therefore,this thesis proposes an improved three-loop NDI controller based on Adaptive Integral Sliding Mode（AISM）.Firstly,the F-16 motion model is di-vided into a velocity loop,an attitude loop and an angular velocity loop by using the singular perturbation method,and then an AISM/NDI controller is designed for each loop to further enhance the robustness against mismatched disturbances by combining the AISM controller with the NDI controller.The stability of the AISM/NDI controller is then demonstrated by using the Lyapunov function.Although the AISM/NDI controller guarantees the flight quality of flying at high an-gle of attack,it does not solve the time lag problem of the flight control system.Therefore,the first-order Active Disturbance Rejection Control（ADRC）for the attitude and angular velocity loops is designed to address that problem.At the same time,to acquire ADRC parameter,Adaptive Genetic Algorithm-Particle Swarm Optimization（AGA-PSO）is also designed.Based on the work before,two controllers showed above have great significance than the conventional NDI controller after the simulated experiment.To further verify the effectiveness of the above work,a software-in-the-loop simulation platform for a fixed-wing vehicle is built,through which the simulated flight of flying at high angle of attack is realized.The simulated result shows that the designed controllers have good control effects.The designed controllers have good theoretical and engineering application value,and can provide reference for the design of anti-disturbance controllers. |
