Attitude tracking of UAV based on nonlinear disturbance rejection control

For the attitude tracking problem of the UVA, the controller is proposed to make the system attitute follow the reference with the consideration of model uncertainty and external disturbance. Firstly, based on the attitude dynamics of the servo system, the nonlinear error model is established by the quaternion. Then, a nonlinear generalized predictive controller is designed based on the error model, the NDOB is used to estimate system uncertainty and disturbance. At last the performance of NDOB is analyzed by the theory of frequency domain. The experiment results suggest the validity of the proposed method in this paper.