Research On Road Condition Detection Technology Based On Complex Impedance Measurement

In recent years,as the mileage of highway construction in China continues to increase,road safety issues under severe weather have received increasing attention.Highway traffic management departments timely grasp information on road surface conditions such as icing and snow,and quickly release early warning information by road surface condition detection technology.This measure will improve highway maintenance and management efficiency,and reduce the risk of traffic accidents caused by bad weather.On the basis of electrochemical theory and electrolyte theory,This thesis achieves different detection of different road surface conditions such as dry,snow,water,icing,etc.with using electrochemical impedance spectroscopy.This thesis also studys the relationship between the resistance and concentration of calcium chloride solution Salt solution resistance,and achieves the freezing point of the solution.This thesis constructes equivalent circuit model of four road surface conditions such as dry,snow,water,and icing,based on the relevant principles and methods of electrochemical impedance spectroscopy and commonly equivalent components.The accuracy of the model is verified by LCR impedance analyzer and ZSimp Win analysis tool.At the same time,based on the electrolyte theory,the mathematical relationship between the resistance and concentration of the calcium chloride solution is derived.Combining the mathematical model of the solution concentration and freezing point,a method for detecting the freezing point of the salt solution using the solution resistance is proposed.On the basis of theoretical analysis,this thesis proposes a complex impedance road surface condition sensing system based on electrochemical impedance spectroscopy and gives the hardware and software design of the sensor.Under the excitation frequency of 10 Hz ～ 8MHz,using the data collected by the LCR impedance analyzer,the equivalent circuit models of different road surface conditions are tested and verified,which proves the accuracy of the model.The road surface condition detection test of the sensor was carried out,combined with the measurement results of the LCR impedance analyzer,the effectiveness of the sensor was verified.At the same time,using data collected by sensors to train and classify different road surface conditions based on K nearest neighbor algorithm,it realized the recognition of four road surface conditions such as dry,snow,water,icing.The designed sensor realizes the function of integrating road surface condition recognition and freezing point detection.Its recognition accuracy rate is 92%,which has good application value and prospect.