Research On Flight Control System Of Quadrotor UAV

Quadrotor UAVs are widely used in military and commercial fields due to their simple mechanical structures,strong maneuverability,and vertical taking-off and landing.With the continuous deepening of research,the requirements for safety,stability,and autonomous flight capabilities of quadrotor UAV have been raised.However,because of the fact that the quadrotor UAV is an underactuated,strongly coupled non-linear controlled object and its load capacity is limited,these factors make the study of its flight control system a priority.Based on the analysis of the flight mechanism of the quadrotor UAV,the ground coordinate system and body coordinate system are used to describe the position and attitude angle of the quadrotor UAV,and a mathematical model of the quadrotor UAV is established according to the Newton-Euler formula.Stabilization control of the attitude is the basis for the trajectory tracking of the quadrotor UAV.In this paper,the attitude of the quadrotor UAV in the dynamic environment is easily disturbed and there is a coupling between the attitude angles.The attitude controller is designed using the linear active disturbance rejection control.The following simulation in the Matlab/Simulink results show that the linear active disturbance rejection controller has good attitude tracking ability and anti-jamming characteristics.As to the nonlinear characteristics of the quadrotor UAV mathematical model,a double closed-loop trajectory tracking control system based on the linear extended state observer and backstepping method is designed.The dynamic surface controller is introduced into the design process of the controller to avoid "differential explosion" of the classical backstepping method.Simulation experiments show that the proposed strategy can achieve accurate trajectory tracking in the presence of external disturbances.The hardware and software parts of the quadrotor UAV flight control system are designed and completed.The STM32F407 microprocessor is used as the main control chip,then the inertial measurement,battery management,data storage,PWM capture and output,and wireless data transmission modules are designed.Software development is performed in Keil.Programs the initialization,inertial measurement module data acquisition and processing,PWM input capture and generation,and the functions are implemented in the microprocessor.The ground control station is designed in LabVIEW.It mainly performs the monitoring of the flight status and the function of transferring the control parameters to the quadrotor UAV,avoiding the process of repeatedly burning the program during the debugging.Finally,the quadrotor UAV is used as the experimental platform.The parameters of the attitude controller are respectively adjusted through the debugging platform,and the effectiveness of the algorithm is verified by the experiment.Finally,the hovering experiment is conducted.The experimental results show that the designed quadrotor UAV flight control system can achieve stable attitude controlling and meet the design requirements of the flight control system.