During the trajectory tracking process and low altitude flight of quadrotor, wind gust and ground effect will significantly affect the accuracy and stability of the controller. Therefore, it is vital for a quadrotor to have a robust controller against multiple disturbances. To mitigate this challenge, an active anti-disturbance control strategy based on generalized extended state observer is proposed in this article. Firstly, quadrotor dynamics is modeled as cascaded translational and rotational loops, and the characteristics of wind gust and ground effect are analyzed. Secondly, two generalized extended state observers are constructed for those loops respectively to estimate and attenuate the impact of wind gust and ground effect, and the position and attitude controller are designed based on backstepping method. Finally, real time experiments are carried out on hovering and circle trajectory tracking conditions. The results illustrate that the proposed controller has more advantages in high precision trajectory tracking and low altitude flight of quadrotor in existence of multiple disturbances.
Non-Recursive Fixed-Time Convergence Observer and Extended State Observer
