Pflimlin, Jean-MichelHamel, TarekSoueres, PhilippeMahony, Robert2015-12-08May 15-190-7803-9505-0http://hdl.handle.net/1885/34980This paper describes a control strategy to stabilize the position of a Vertical Takeoff and Landing (VTOL) Unmanned Aerial Vehicle (UAV) in wind gusts. The proposed approach takes advantage of the cascade structure of the system to design a hierarchical controller. The idea is to separate the controller in a High Level Controller devoted to position control and a Low Level Controller devoted to stabilization and attitude control. Both controllers are designed by means of backstepping techniques that allow the stabilization of the vehicle's position while on-line estimation of the unknown aerodynamic forces. The global stability of the connected system is proven, and simulations as well as experimental results are presented.Keywords: Computer simulation; Ducted fan engines; Hierarchical systems; Navigation systems; Stabilization; Unmanned vehicles; VTOL/STOL aircraft; Cascade structure; Ducted fan flying robot; High Level Controller; Unmanned Aerial Vehicle (UAV); Mobile robots200610.1109/ROBOT.2006.16420762015-12-08