Development And Experimental Study Of Impedance Pavement State Sensor

With the rapid development of express logistics and other industries,China's highway construction level is constantly improving and the scale of construction is expanding.As the expressways extend in all directions,the number of traffic accidents on the expressways is also rising.About one-quarter of the traffic accidents are caused by bad weather such as high winds,rain,snow,ice,etc.It is especially important to establish a road weather information warning system with icing sensors for complex road conditions as the core..Through research on the field of road junction detection at home and abroad,it is found that some developed countries have established a relatively complete road meteorological monitoring and early warning information system,the core of which is the road icing sensor,which can accumulate water,freeze,snow,etc.The status is identified,and even specific thickness information can be given as a data source for the road weather monitoring and warning information system.Domestic research is relatively weak.In addition to research conducted by a few universities,domestic sensor products have been imported.In view of this situation,this thesis proposes an impedance icing sensor based on the original pressure level film and photoelectric sensor of the research group.Starting from the dielectric properties of air,water and ice,the dielectric properties of air,water and ice are analyzed by the polarization phenomenon of dielectric,the dielectric loss law of dielectric and the Debye relaxation model of dielectric.The difference is derived from the equivalent conductance and capacitance of the measured object and the mathematical relationship between the impedance modulus and the phase angle in the frequency domain.It is theoretically proved that the impedance sensor can detect the state that the road surface is air,water or ice.Correctness.Based on impedance,combined with pressure level film and photoelectric icing sensor,this thesis proposes a multi-sensor road icing detection method and designs a new icing sensor system.In this thesis,the feasibility of the impedance icing sensor is verified by a large number of experiments.The temperature characteristics of the sensor and the influence of salinity on the performance of the sensor are studied.The test results show that the sensor is not sensitive to temperature and can be used at-20 °C-20 °C.The road surface condition is accurately identified,and the sensor can still correctly identify the road icing state in a salt solution environment with a concentration lower than 30%.