Design And Implementation Of Attitude And Height Control Method For Quadrotor UAV

The rapid development of quadrotor UAV technology has broad application prospects.It has become a concern of researchers for designing high-performance control algorithms about the strong nonlinear coupling and disturbance existing in the quadrotor model.The stable and anti-disturbance ability of the control algorithm can improve the flight performance of the quadrotor.This paper establishes the nonlinear dynamic model of the quadrotor UAV based on the dynamic knowledge and Newton’s law of motion considering the conversion relationship between the angular velocity of Euler and the angular velocity of the body.The parameters of the quadrotor model are obtained through measurement and experiment on the basis of completing the construction of the quadrotor aircraft hardware platform,and the simulation model of quadrotor is built based on Simulink.In this paper,a quadrotor cascade PID control system is designed based on the principle of PID control.The simulation results show that the cascade PID controller can achieve better expected follow-up and stable control effects.However,the coupling existing in the quadrotor model cannot be well suppressed.At the same time,the control performance is significantly degraded and the stable control of the aircraft cannot be guaranteed when the disturbance is added to the system.This paper represents each channel of the quadrotor attitude model as a cascade system by analyzing the nonlinearity and coupling existing in the model of quadrotor UAV and considering the nonlinear coupling relationship between the Euler angular velocity and the angular velocity of the quadrotor.A cascade ADRC attitude controller is designed for each cascade system.The nonlinear coupling and external disturbances in the system are observed by two extended state observers of the inner and outer loops respectively,and finally compensated by the nonlinear state feedback link.At the same time,this paper designs a ADRC height controller.The simulation results show that the cascade ADRC attitude controller designed in this paper can achieve good control effect when there are coupling and external disturbances,and the ADRC height controller can suppress external disturbances well.Finally,the PID control algorithm and the ADRC algorithm are implemented based on the quadrotor development environment built in this paper.The control performance of the PID control algorithm and the ADRC algorithm is compared by flight experiments,which verifies the superior control performance of the ADRC control structure designed in this paper.