Attitude control of quadrotor UAV based on integral backstepping active disturbance rejection control

For the attitude control system of a quadrotor unmanned aerial vehicle (UAV), an integral backstepping active disturbance rejection control strategy is proposed to solve the tracking and disturbance rejection problems in flight control. To solve the problem of buffeting near the origin of traditional nonlinear functions, this paper designs a function newfal(.) with better smoothness near the origin. Second, to improve the observation performance of the extended state observer and the anti-disturbance performance of the controller, an improved expanded state observer (IESO) based on error is designed according to the working principle of expanded state observer (ESO) and the tracking law of state variables. Then, to improve the tracking accuracy of the controller, the integral term is introduced into the backstepping method and uses the idea of recursion to design the nonlinear backstepping integral control law. Combining the disturbance estimation and compensation functions of active disturbance rejection control (ADRC), an integral backstepping active disturbance rejection control is designed and applied to the attitude angle control channel of quadrotor UAV. Finally, experimental results indicate that the designed control strategy can realize high-precision tracking of the attitude angle of a quadrotor UAV, achieve fast dynamic response, and improve the anti-interference.