Attitude Control of Underactuated Quadrotor UAV Based on Improved ADRC

In this paper, a cascaded control framework based on active disturbance rejection control (ADRC) is proposed for underactuated quadrotor unmanned aerial vehicle (UAV) to improve the stability of attitude control and the ability of anti-disturbance. The model of quadrotor is given in the first, and then the improved active disturbance rejection control is applied into angular speed controller, the improved nonlinear extended state observer (NLESO) not only considering the delay of motor but also using a smooth nonlinear function which enhanced the accuracy of state estimation. The simulation results show that the improved ADRC performs better in both of the ability of attitude tracking and the ability of anti-disturbance.