Autonomous Control System Design For The Four-rotor UAV

Four rotor unmanned aerial vehicle (uav) is an electric, capable of vertical takeoff andlanding (VTOL), multiple rotor remote control of autonomous aircraft. The four rotoraircraft has a cross symmetrical frame structure, and the same type of brushless DC motorwith propelle are fixed on four endpoints of the frame, by controlling the speed of fourmotors to achieve the different flight attitudes of the aircraft. The four rotor aircraft hascomplex characteristics such as nonlinear, strong coupling, the underactuated and multipleinput multiple output. Because of its vertical takeoff, hover and forward flight, invertedand lateral flight and flight attitude characteristics, the four rotor UAV is applied more andmore rich, and becomes the focus of research at home and abroad in recent years.In this paper, a four rotor aircraft was the research object, and its autonomous controlsystems was primarily designed. We used this system as a fundamental, design andconstructed a simulation model of the aircraft, and completed the flight test finally. First ofall, according to flight principles of the four rotor aircraft, dynamics analysis of aircraft,and Newton’s second law of motion and torque balance principle, we carried mechanismmodeling on the body, established the nonlinear dynamic model of the body. We linearizedthe nonlinear model organism baseing on LPV and obtained a linear dynamic model whichcould be easily simulated control. According to the relevant data we analyzed andsummarized algorithm algorithm analysis of four rotor aircraft attitudes. Secondly, we builtthe simulation model of the system in Matlab/Simulink according to the dynamic modelof four-rotor aircraft, and designed PID controllers on the height, pitch angle, roll angle,yaw angle of the four channels individually. We achieved stability control of postures byPID control algorithm, and validated PID control algorithm by simulation. Thirdly, weselected the aluminum cross as the structural frame, brushless DC motor as the drivingforce part,STM32the controller, MEMS gyroscopes accelerometers and magnetoresistivesensor as the detect section, building a four-rotor aircraft research platform. Fourthly, we did the data acquisition and processing for the four-rotor aircraft sensor, did raw dataacquisition for accelerometers and gyroscopes by the I2C bus, did data processing by themean of filtering and the moving average filter, and fused the collected data by quaternion.We synthesized attitude information, got the spacecraft attitudes of the aircraft, andcontrolled the four-rotor aircraft on the research platform according to the attitudeinformation.The difficult point of this essay is the accurate modeling of the system, thecombination of controllers designed according to the simulation model and the actualhardware system, and completed the flight test finally.