Adaptive Control For Quadrotor Unmanned Aerial Vehicles

Quadrotor unmanned aerial vehicles(UAV)is an aircraft that generates lift through four rotors.Due to its simple structure,small size,high flexibility,quadrotor UAV has a good development prospect and a large number of applications in many industries,such as reconnaissance,logistics,agriculture,and so on.In this thesis,the quadrotor UAV is taken as the research object.Considering the external interference and actuator failure of the quadrotor UAV,the controller of the quadrotor UAV is designed using sliding mode control and adaptive control methods.The main contents of research include:Firstly,the structure and flight principle of the quadrotor UAV are explained,and the body coordinate system and ground coordinate system are established based on related knowledge.Euler angles is selected as attitude angles,and the transformation matrix from the body coordinate system to the ground coordinate system is derived.The dynamic model of the quadrotor UAV is established based on Newton’s second law and angular momentum theorem.Secondly,an adaptive sliding mode controller is designed for quadrotor UAV to enable trajectory tracking.Considering the situation when external disturbances may exist in the quadrotor UAV system during flight,based on the classical sliding mode control method,a classical sliding mode controller is designed.An adaptive law is designed based on adaptive control theory to estimate the disturbance variable in real-time and compensate for it in the controller.Simulation results show that the adaptive sliding mode control method can effectively suppress the influence of external disturbances.Finally,a fault-tolerant control method is proposed for the actuator failure of a quadrotor UAV.By using an adaptive observer to estimate the external interference and actuator fault variables of a quadrotor UAV,the adaptive observer can limit the observation error to a certain range.A sliding mode controller is designed based on sliding mode control theory.The faulttolerant controller design for a quadrotor UAV is completed by adding the estimated disturbance variables obtained from the observer to the controller.The controller design process is based on Lyapunov stability theory,ensuring the stability of the system.The simulation results show that the quadrotor UAV using this method has better fault tolerance and anti-interference capabilities.