Position tracking and attitude control for quadrotors via active disturbance rejection control method

In this paper, a trigonometric-saturation-function-based position controller is designed for the quadrotor system with internal and external disturbances. Furthermore, in the attitude control problem, a dual closed-loop structure is put forward. Specifically, a nonlinear extended-state-observer (ESO) is employed to provide an estimate for the so-called total disturbance. Then, based on the estimate provided by the ESO, a nonlinear composite control strategy is designed for the purpose of angular tracking. Some sufficient conditions are established to guarantee that the position and attitude subsystems are stable. The contributions are mainly as follows. (1) A trigonometric-saturation-function is used in the position control which could guarantee that the studied system is fully-actuated. (2) The nonlinear ESO is implemented in the attitude control-loop which could enhance the anti-disturbance property. Finally, some numerical simulations and practical experiments are provided to verify the applicability of the proposed methodology.