Research On Flight Control System Of Four-rotor Aircraft

With the rapid development of four-rotor aircraft, it is widely used in aerial photography,rescue relief, power inspection, exploration & testing and other civilian and military fields. It has been more and more concerned by people, become the focus of research in recent years.The main research contents are the flight control of the four-rotorcraft in this paper, which can reach the fixed-point and stable flight through the control algorithm,maintain the good flight attitude in the case of the non-GPS or Beidou positioning signal in the room.Firstly, the flight principle of the four-rotor aircraft is analyzed, and the mutual conversion between the body coordinate system and the inertial coordinate system is explained. Mutual transformation between Euler angle and quaternion, according to the structural characteristics of the four rotorcraft and the requirements of flight control, design hardware overall, divide into motor drive module, the main control module, the attitude module and the autonomous positioning module. Select the Arduino UNO and Arduino Nano to form the main control module, the attitude module select motion processing sensor MPU-6050 responsible for flight attitude data acquisition, autonomous positioning module select ultrasonic sensor Hc-SR04 to transmit the height of the aircraft, the visual sensor Pixy to pass its horizontal position. In addition, according to the control needs and cost-effective comparison, select the hardware to the control center of the erack, electronic governor,brushless motor and other components are, build a practical and reliable, easy to expand four-rotor aircraft. Then, it designed software structure of aircraft control, orientate to its structure features and fly control requirement of four-wings aircraft. Use positional double closed-round PID controller to control fly pose, fly level position and height, external round reflects fly status (displacement)difference, internal round reflects fly status (speed)difference,in order to make final output value more closer to expected value, external round output as input of internal round again, through the outer ring and inner ring dual control,so that the four rotorcraft flight is more stable, faster and accurate indoor positioning. The positional double closed-loop PID attitude control and position control are realized through Arduino language.Finally,direct mistake to data which collected by every sensor in Arduino platform,allocate code to procedure. Place some targets in a vacant laboratory, control fly pose to fourOwings aircraft and indoor self-positioning control unification test, through many times of flying test, apply adjust skills and experiences to adjust PID parameter repeatedly and made four-swings aircraft realized indoor self-positional stable fly under the situation of non-GPS signal. Trying fly indicated that positional double-closed round PID controller applied by the article can control four-swings aircraft fly pose and indoor self-positioning steadily and effectively.