Research On Anti-Interference And Fault-Tolerant Control Of Quadrotor Unmanned Aerial Vehicle

As a representative product in the field of artificial intelligence,the Quadrotor UAV has been widely used in real life due to its increasingly mature flight control technology.However,it is easy to be affected by external interference and the sudden failure of the UAV when carrying out the target flight mission,resulting in the instability of the UAV flight posture.Therefore,the research on the four-rotor UAV control system with anti-disturbance and fault-tolerant function is of great significance to increase the security and reliability of UAV flight control.In this paper,the anti-disturbance control technology and fault-tolerant control technology of Quadrotor UAV are studied as follows:(1)The kinematics model and dynamics model of the four-rotor UAV are constructed respectively.Based on the common interference and fault forms of UAV,a four-rotor UAV model is constructed in the case of external interference and actuator failure,and then a fourrotor UAV model is established in the case of both external interference and actuator failure.On the basis of the modern control theory,the state space models of the Quadrotor UAV system under the above three cases are established respectively.(2)Aiming at the problem of unknown external disturbance in the four-rotor UAV model,an anti-disturbance control method based on interval observer is proposed.According to the stability criterion of the positive system,the interval observer based on linear matrix inequality(LMI)is designed,the freedom parameter is introduced,the external disturbance value is estimated,and then a controller is designed to effectively suppress the disturbance term,so as to achieve the stable flight of the UAV and anti-disturbance control of the four-rotor UAV.(3)An adaptive fault-tolerant control method is proposed for the failure of the four-rotor UAV actuator.Firstly,the fault estimator is designed for the system fault item,can realize online estimation of actuator fault signal.Then,using the fault estimator on the estimate of fault signal to design the method based on control allocation distributive law of control,to reduce the fault signal of adverse impact of the four rotor UAV attitude and finally realizes the fourrotor fault tolerant flight control of UAV.(4)For the four-rotor UAV model,considering the simultaneous occurrence of external disturbance and actuator failure,a fault-tolerant composite controller method combining robust control,disturbance observer and fault estimator is proposed.Under the condition of external bounded disturbance and additive fault,the trajectory tracking of the four-rotor UAV is realized.Firstly,the nonlinear dynamic model of the four-rotor UAV is decoupled into an independent outer ring position control system and an inner ring angle control system,the interval matrix is introduced to describe the system parameters,and the disturbance observer and fault estimator are used to estimate and compensate the disturbance and fault.Then,a composite controller is designed to not only suppress the disturbance better but also ensure the smooth flight of the UAV in the case of its own failure,so as to realize the composite control.