The Design Of Four Rotor UAV Control System

Currently available rotor unmanned aerial vehicles(UAV)are divided into three rotor unmanned aerial vehicles,four rotor unmanned aerial vehicles,six rotor unmanned aerial vehicles and fixed wing unmanned aerial vehicles.Among them,the four-rotor UAV has a lot of advantages such as small volume,flexible operation,simple control,vertical takeoff and landing and no requirement for take-off and so on.So this kind of UAV has a wide range of applications in agricultural,rescue,disaster relief and military.In this context,this paper summarizes the difficulties encountered in the control system of UAVs,designs a four rotor UAV system,and complete the work of implementation and debugging of this system based on chip STM2F07.The four-rotor UAV system is under-driven,strongly coupled and multivariable,since the four-rotor UAV has only four drive units to control the 6-DOF body.To establish its mathematical model,the four rotor UAV is regarded as the rigid body,the dynamic model is established by using the Newtonian mechanics model,and the nonlinear mathematical model is obtained,and the parameters of the mathematical model are optimized by experiment.According to the design,the chip STM32F407 is selected as the core control unit,which has a great advantage compared to STM32F1 x series and STM32F2 x series.This chip’s core performances much better in storing and manipulating instructions,pointers and data.The four-rotor unmanned aerial vehicle control system is based on the real-time detection of the attitude of the four rotor UAV,which includes measuring the attitude angle and the attitude change rate of the four-rotor UAV.Because vibration,electric field and magnetic field is easy to affect the detection of a single attitude detection element,the detection principle and characteristics of the single attitude detection unit are studied firstly,and the feasibility and accuracy of the multi-sensor in data fusion are proved to improve the reliability of the data.In the control unit of the four rotor UAV,the improved fuzzy PID is used as a controller.The traditional PID controller is too slow to response after interference and Imprecise in a small range of fuzzy control.The effects of the traditional PID fuzzy control and improved fuzzy PID control are compared by simulation.After designing the control system,the hardware is purchased,and the control program of the function module and the system of the flywheel and the various sensors are programmed.Designed posture estimation and control sections are jointly downloaded to the flight control board for experimentation and commissioning.The results show that the multi-sensor fusion can achieve the better attitude of the four-rotor UAV,and the flight control system has good stability and fastness in the experimental environment with wind speed of 3m / s.