Controller Design For Quadrotor Unmanned Aerial Vehicle Based On Backstepping Technique

As a kind of Micro UAV (Unmanned Aerial Vehicle), quadrotor UAV has special superiorities:simple mechanical structure and strong maneuverability which make the quadrotor easy to achieve VTOL (Vertical Take-off and Landing), hover at static state and execute acrobat movements. Because of these advantages, quadrotor UAVs have been developed for performing various missions in both military and civilian areas.However, the high performance control of quadrotor UAV is a difficult task because it is a multivariable, nonlinear, state-coupling and under-actuated system subjected to uncertainties. The purpose of the thesis is to design appropriate algorithms to realize the hovering control, trajectory tracking control and adaptive trajectory tracking control of quadrotor UAV. The thesis divides the system into two control loops, horizontal position controller and altitude controller are designed as outer loop, and attitude controller is designed as inner loop.Firstly, the thesis applies backstepping technique which is based on Lyapunov stability theorem to design the hovering controller. With the controller, the quadrotor UAV can not only reach the target position accurately, but also remain stable when hovering; Secondly, the trajectory tracking controller of quadrotor which is designed based on integral backstepping technique makes the quadrotor UAV able to track the anticipated trajectory precisely; Finally, in view of the uncertainties of the quadrotor, the thesis combines backstepping technique with nonlinear adaptive control to design the controller which can achieve the adaptive trajectory tracking control of quadrotor UAV. The controller not only can control the quadrotor precisely, but also has strong anti-disturbance and environmental adaptive abilities, which leads to good stability and strong robustness.The proposed control algorithms are implemented in Matlab/Simulink for simulation experiments to verify the validity and effectiveness. Then, the thesis makes detailed analysis and comparisons of the simulation results of the three control algorithms. The simulation figures show that all the proposed algorithms can realize the goal of control respectively and the control performances are guaranteed. The control algorithms provide a vital theoretical foundation for the practical application of the quadrotor.