Aiming at problem that UAV in the whole longitudinal plane flight process

due to the large range of flight attitude angle and the effect of air flow

resulting in trembling

affecting flight stability

present a control and anti-chatter algorithm for UAV flight attitude angle based on PID variable structure control. Parametric analysis on controlled object of flight attitude angle control system is carried out. Three-channel model for UAV in dramatic change of attitude angle

large angle of attack flight

controller is designed with variable structure control method.The disturbance rejection and stability are proved by small perturbation theory and Lyapunov stability theory.Gradient algorithm is used to adjust weights for anti-chatter processing by flight attitude angle control. The adaptive algorithm is used to online adjust the weights to realize improvement of PID variable structure control. The simulation results show that using this algorithm to control attitude angle of UAV and realize anti-chatter

precision of UAV flight attitude is greatly improved

the control precision of roll angle

pitch angle and heading angle is greatly improved

stability and convergence are good

which ensure flight stability of UAV.