Transition attitude control of a tail-sitter UAV based on active disturbance rejection control architecture

The reliability of the transition flight is crucial for the full-envelope flight of the tail-sitter UAV. The nonlinear characteristics, including aerodynamic changes, environmental wind fields and other factors that are not considered would influence the tail-sitter UAV during the transition process. In addition, the differences between the established aircraft model and the actual system are also inevitable. Effectively compensating for the uncertainties and disturbances mentioned above to ensure the good attitude of the UAV, brings a significant challenge to the design of control system. The active disturbance rejection control (ADRC) has the characteristic of good estimation and compensation ability for uncertainty and is independent of the controlled object. Therefore, this control architecture is explored for the attitude control of the tail-sitter UAV during the transition process in this study.