Research On Autonomous Flight Control For UAVs Of Geophysical Exploration

In the period of mineral resources shortage around the world, an aerial geophysical exploration technology based on UAVs, which is flexible, efficient and safe, has long been received extensive attention of scholars in the international community and has become a hotspot in research. At present, our country is still in the early research state in the use of UAVs for aerial geophysical exploration. Most of issues are still in exploration, for example the platform selection, the flight control method and so on. In the experimental study for mow, most use fixed wing UAVs as geophysical exploration platforms. Considering all above, this paper selected a micro four-rotor UAVs as the platform and studied on the low-altitude and low-speed autonomous flight control of it.This paper selects classical PID control theory to design the controller for the flight control system of UAVs platform by summarizing aviation detection without man-machine technology of domestic and foreign research status, and several flight control algorithm commonly used non UAVs. Based on analysis of the structure, force and flight principle of the UAVs platform, the dynamic model of platform system is established by combining with the Newton Euler equations. With simplifying the model system, the platform flight control system is divided into three control loops in velocity, attitude and position. Respectively design PID controller in Matlab software and do simulation experiment. The experimental results verify the effectiveness of the designed PID controllers. A flight control system is designed based on STM32, which is suitable for UAVs. The system mainly includes five modules: control, measurement, motor driver, wireless communication, power and so on. The control module receives the command from ground station, then calculates the control quantity of the electric motors according to the datum from measuring module, and outputs PWM signals. The measurement module includes three parts, including inertial, direction and pressure. The motor driver module enlarges the output PWM signal to non-brush motor drive. The wireless communication module selects 3-DR radio to complete the data transmission between airborne part and ground station.The experimental results verify the designed platform flight control system in this paper, has accomplished the controlling function of roll, pitch, yaw and height. In the experiment, the roll, pitch and yaw angle are all controlled in the range of 1 degree and the height is no more than 0.2m. It shows the feasibility of the UAVs platform control method, which lays foundation for further research of autonomous flight control.