Robust Attitude Tracking Control for a Quadrotor Based on the Uncertainty and Disturbance Estimator

In this paper, a robust control method based on the uncertainty and disturbance estimator (UDE) is developed to achieve the attitude tracking control for a quadrotor. To facilitate the control design, the coupled terms in the roll, pitch and yaw dynamics are lumped into the uncertainty term and the remained dynamics can be regarded as decoupled subsystems. As a result, for each subsystem, the lumped uncertainty term contains all the coupled terms, uncertainties and disturbances, then the UDE method is applied for the uncertainty compensation. Compared with the existing UDE control works, the introduced filtered tracking error dynamics simplifies the controller design and implementation. Furthermore, the stability analysis of the closed-loop system is established and experimental studies are carried out to illustrate the effectiveness of the developed control method.