Research On Rapid Heavy Metal Detection System For Soil With UAV Based XRF Technology

Soil is the most important material basis for human survival and development.The rapid economic and social development has also brought global soil pollution problems,especially heavy metal pollution that seriously threatens food quality and safety.Traditional chemical analysis and Instrumental analysis methods for heavy metal pollution detection have the inevitable shortcomings: high cost,long test cycle,and potential secondary pollution.There are also certain limitations in the practical applications of those methods.Therefore,fast and convenient detection methods for heavy metal pollution of soil need to be developed.XRF(X-Ray Fluorescence)spectroscopy widely used analysis method to investigate soil element contents.It has significant advantages such as convenience,speed,no damage to sample properties,stable and reliable results.The technology can simultaneously analyze and detect a variety of elements,but the current commercial portable XRF analyzer requires manual operation,and it is difficult to quickly complete the detection and evaluation of the overall pollution in a large area.Unmanned Aerial Vehicle(UAV)technology has been developed at a high speed in recent years.Due to its flexibility,low cost,and low terrain constraints,its application fields are being continuously expanded.This research aims at the rapid detection of soil heavy metal pollution in a large area.It combines XRF and UAV technology to give full play to their respective technical advantages and integrate embedded development,computer software,electronic information,and other technical methods.This research focuses on the key technology of the UAV-based rapid detection system for heavy metal pollution of soil.The main research content is as follows.(1)Firstly,to assist the UAV’s safe and accurate fixed-point hover two separate modules for height-fixing ground contact monitoring are developed based on UAV,portable XRF analyser,Raspberry Pi 4B,pressure sensor,ranging sensors,electric push rods and DC push-pull electromagnets and other hardware equipment,to develop a system height-fixing module and a ground contact monitoring module to assist the UAV to achieve safe and accurate fixed-point hover.Then,develop a data acquisition drive device to replace manual control to realize automatic XRF data collection.(2)Enable portable XRF analysis of near the ground collected data,by integrating the Raspberry Pi 4B and linear least square fitting data inversion method,the inversionprocessing algorithm for specific soil heavy metal content is studied and implemented.As such,the portable XRF analyzer can automatically and accurately detect the content of heavy metals in soil at a certain distance.(3)On the basis of the above,complete the key algorithm design and implementation of UAV coordinated control and automatic flight,and carry out UAV flight mission planning and task queue construction,automatic control of flight height and speed,etc.Finally,the software and hardware modules are integrated organically and optimized to get a set of UAV-based XRF rapid detection systems for soil heavy metal pollution.This study is preliminary research and exploration for regional,rapid and convenient soil heavy metal pollution detection,whose purpose it is to provide a new solution for the problems encountered in the practical application of soil heavy metal pollution detection.