Research On Terrain Following Control System Of Multi-rotor UAV

In recent years,multi-rotor unmanned aerial vehicle(UAV)has been widely used in various fields.In power inspection,pesticide spraying and long-distance mapping,the flying altitude of UAV needs to change with the change of terrain.For example,during the operation of pesticide spraying,the UAV always maintains a constant height difference with the crop canopy,so as to ensure more uniform pesticide spraying and reduce pesticide waste.With the help of terrain following function,the plant protection UAV can be used in different terrain to achieve better plant protection effect.Aiming at the problems of poor real-time performance and large calculation volume of the existing terrain following system,this paper designs a ground-based flight control system based on lidar,which solves the shortcomings in the existing technology well.The core of terrain tracking lies in the realization of ranging technology.This article chooses lidar to achieve ranging.The specific design scheme is to design a ranging system based on lidar,transmit the distance information to the flight control system,and realize flight simulation through the flight control system.In order to ensure the accuracy of the ranging system,a gimbal stabilization system is designed,the flight control system sends the UAV attitude data to gimbal in real time.The gimbal will combine the attitude of the drone with the attitude of the lidar.It ensures that the ranging direction of the lidar remains the same,always measuring the height of the UAV relative to the ground directly below.Aiming at the realization of the whole system,it uses the two-way wireless data transmission,the multi-rotor data in the air can be transmitted to the ground station in real time;At the same time,the flight control system can receive the flight mission sent by the ground station,and the UAV can determine the destination position according to the GPS,and then adjust the attitude of the UAV to fly to the mission site.Firstly,the hardware system of terrain tracking is designed,including lidar ranging system,gimbal stabilization control system and aircraft control system.Then,terrain following algorithm design is carried out,including UAV modeling,attitude calculation,stability control,terrain following algorithm and analysis of gimbal stabilization algorithm.Next,a brief introduction to the terrain following operating system.Finally,the test flight results show that the system only uses a single rangefinder,which reduces the computation,and can still achieve good real-time terrain tracking.