The Relability Analysis And Application Of The Water Film Thickness Sensor

With the rapid development of our country's highway construction,the importance of road sensors in the field of highway traffic is continuously strengthened and has an more promising market. Road sensor can service for road weather stations, remote monitoring of specific locations to get the meteorological parameters all-weather and accurately.Water film thickness detection sensor, as an important part of the road surface sensor system, is mainly applied to measure the thickness of surface gathered water.This paper is mainly focus on the two aspects of research about water film sensor including the reliability and applicability.(A) In the aspect of reliability:(a)Analyzes the effects of water film sensor reliability bring by the misreading and temperature effect problems.(b)Analyzes the causes of misreading and temperature effect problems.(c)Aiming at the causes of the above analysis, puts forward the corresponding solutions.By adjusting the working frequency of the sensor to solve the problem of misreading caused by the amplitude phase detection chip AD8302.To make microwave signal of incident wave and reflected wave amplitude ratio and phase difference in AD8302 chip interval of low error.In view of the control voltage of generator, designed a bias circuit based on the MOS transistor to replace the resistance of bias circuit, the new bias circuit not only reduces the influence of unstable power supply but has a temperature compensation function.(B) In the aspect of applicability:(a)According to the Bernoulli equation in fluid mechanics, calculate the fixed relationship between water film thickness and liquid flow;(b)Designs a suitable device to realize measuring rainfall.(c)Two methods of measurement about rain gauge device are introduced in detail.(d).The device parameters and software of the rain gauge are designed,finally, the function of rain gauge device is validated and measurement results is analyzed.According to the experimental data,misreading and temperature effect problems are solved.The overall prototype design of rain gauge are implemented,rain gauge validation data shows the rain gauge can measure rainfall intensity range of Omm/min to 4mm/min and the resolution of the rainfall intensity is 0.0086 mm/min.