Altitude control of quadrator UVAs using high gain observer-based output feedback high gain regulator

The motivation of this paper consists in investigating the challenging regulation problem involved in altitude flight dynamics of quadrotor unmanned airborne vehicles in presence of wind disturbances and modeling errors. To this end, we first provide a reliable output feedback regulator involving a state feedback linearization and disturbances compensation together with a high gain observer performing an appropriate estimation of the system state variables as well as the disturbances. Such a regulator is then used to maintain a quadrotor unmanned airborne vehicle at specific orientation despite the wind dynamics and those ubiquitous modeling errors. A particular emphasis is put on the essential properties of the state feedback control system and the observer under consideration, namely the stabilization and the wind disturbances compensation with an admissible transient behavior. The effectiveness of the proposed regulator is particularly studied in a simulation framework involving a realistic physical model of a quadrotor unmanned airborne vehicle.