Research On Flight Control System Of Four-rotor Uav Based On Fuzzy Adaptive Pid Control

In recent years,with the development of technology and flight control system mature,multi-rotor unmanned aerial vehicle(UAV)has been accepted and loved by more and more people.In the design,the most basic and core issue of flight control system,as the UAV's brain,is how to make the UAV hover independently more stable in the air.This paper to four rotor UAV as the research object,designed a set of basic flight control system,and contrast in the UAV control effect of the different PID attitude.Firstly,the mathematical model is established from vertical flight,roll flight,pitch flight,yaw flight and their force and movement of the four-rotor UAV,then,verified the correctness of the mathematical model through MATLAB simulation.The paper defined four input quantities of the UAV control system,and the mathematical expression of the corresponding control channel transfer function is obtained according to the mathematical model,which lays the foundation for the design and simulation of the whole UAV control system.In this paper,the quaternion is chosen as the carrier to describe the attitude of the four-rotor UAV,and then construct the relationship between the quaternion and the attitude Euler angle,the roll angle,the pitch angle and the yaw angle in the spatial coordinate system.Use the Quaternion differential equation update algorithm to master the UAV in the air posture,and as a follow-up attitude control input.After the completion of the work,and then set out to design the Attitude Control System.Most open source flight control system uses the classical PID control method for attitude control.In this paper,based on the classical single-loop and cascade PID attitude control system,in order to further enhance the stability of the aircraft,a fuzzy adaptive cascade stage is introduced,which is to allow the flight control system change PID parameters intelligently according to the actual flight of the UAV to achieve the optimal control effect.Then,the simulation of the roll angle and pitch angle response of UAV under three kinds of PID control modes is carried out by MATLAB.At the same time,the feasibility of optimization for fuzzy control to Fuzzy Model Reference Learning Control is proposed.Then,reference the principle algorithm to write the software program of attitude calculation and attitude control.At the same time,the hardware and software design of other modules in flight control system is carried out,including the main controller PWM signal acquisition and output,sensor communication module,wireless communication module,and Combine the above modules into a complete basic flight control program.Finally,set up the flight test board and the UAV test platform.Conduct flight test for three kinds of PID attitude control methods in UAV body back to characteristics test and anti-jamming test and so on.The simulation results show that the attitude control module based on fuzzy adaptive PID can make the UAV more stable.