Stabilization Control Of UAVs With Actuator Saturations

Due to the independent hovering, simple structure and strong maneuverability, VTOL(Vertical Take-off and Landing) vehicles have been received a lot of attention in the fields of military and civilian in the recent years. As one common VTOL vehicle, the quadrotor has become the focus of the scientists.Stabilization problem of UAV with the actuator saturations has been studied in this thesis. Firstly, some background of quadrotors & VTOL vehicles and status of research on the actuator have been introduced. Secondly, the dynamic model of quadrotors has been established by the flight principle and the Newton-Euler theorem, decoupling the internal loop of attitude and the outer loop of position. Controllers for the internal and outer loops have been consturcted using backstepping method. Then, the effect of actuator saturations has been given through simulation results. To solve the problem of actuator saturations, the method of rescaling has been introduced, where the static and dynamic approaches are used to deal with the actuator saturations. Finally, control of VTOL vehicles with actuator saturations has been considered, where coupling relationship between position system and attitude system has been included in design of controllers. The method of rescaling is also used to avoid the actuator saturations of VTOL vehicles.The reconfiguration method proposed in thesis can preserve the stability of quadrotors not only for common quadrotors but also for general VTOL vehicles with the actuator saturations.