Position control of a ducted fan VTOL UAV in crosswind

This paper describes a control strategy to stabilize the position of a vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV) in crosswind despite unknown aerodynamic effects. The proposed approach overcomes the problem of gyroscopic coupling by taking advantage of both the structure of the thrust mechanism, which is made of two counter rotating propellers, and the control strategy which involves a decoupling of the yaw rate dynamics from the rest of the system dynamics. The controller is designed by means of backstepping techniques that allow the stabilization of the vehicle's position while online estimating the unknown aerodynamic effects. Acknowledgements The authors wish to express their gratitude to the French Ministry of Research and Technology and the National Direction of Armament DGA for granting this research program. They also thank Olivier Philippe, VTOL UAV project manager at Bertin Technologies, who provided fundings and support in this research. They also address special thanks to the whole drone team of Bertin Technologies for their assistance and advices.