Trajectory Tracking Control Of Quadrotor Based On Backstepping Sliding Mode

Quadrotor aircraft has become a research hotspot in recent years due to its strong maneuverability,ability to fly in narrow spaces,and work in harsh environments.Since the quadrotor aircraft is a typical nonlinear,strongly coupled,multivariable underdrive system and the flight process is vulnerable to interference,the design of its controller has become the difficulty.In this thesis,an improved high-order extended state observer(ESO)is designed to observe and compensate for the external interference and parameter perturbation in the system during the flight of the quadrotor aircraft.The controller is designed combination with sliding mode control,and the backstepping method is used to solve the problem of sliding mode control is difficult to control under non-matching uncertain conditions,which to improve the trajectory tracking control precision and controller robustness of quadrotor aircraft.Firstly,the flight principle and several motion states of the quadrotor aircraft are introduced,and the body coordinate system and the geodetic coordinate system are established,and the conversion relationship between the two coordinate systems is deduced.Moreover,based on the structure and flight principle of the quadrotor aircraft,the aerodynamics model and the motor and propeller actuator model are established according to Newton-Euler theorem.Secondly,an improved high-order extended state observer is designed,and the position and attitude controllers are designed by combining the backstepping sliding mode control method.The backstepping sliding mode control is used to design the controller to ensure the robustness of the quadrotor aircraft system,and the stability of the controller is proved by using Lyapunov stability theory.In view of the compound interference which composed of external interference and parameter perturbation by the quadrotor aircraft,in order to improve the anti-interference ability of the system,a high order extended state observer is used to observe and compensate the compound interference in real time.Thirdly,the chattering problem of sliding mode control is solved by replacing the continuous function of the control law with the symbolic function to enhance the robustness of the system.Finally,in order to prove the performance of the improved high-order extended state observer,the performance of the improved high-order extended state observer is simulated by using matlab.The effectiveness of the controller based on backstepping sliding mode control and high-order extended state observer is verified,and the control performance of the controller is compared with that of the sliding mode controller and PID controller.The results show that the proposed control method has faster response speed,higher tracking accuracy,and enhanced anti-interference ability.