Research And Implementation Of Vehicle Weigh-in-motion System Based On Piezo-Film

With the rapid development of the current economy,China's demand for transportation is growing.Therefore,many companies take the risk of overloading in exchange for short-term and high profits.Such irregularities seriously threaten personnel safety,the service life of road and the interests of the country.So Weigh-in-Motion system is important in highway management.Weigh-in-Motion system achieve road management by automatically acquiring and detecting the vehicle load information,which is collected by the sensor on the roadway.And the system allows the vehicle to drive normally.Thereby it has a particularly high requirement for the stability of hardware devices and performance of the algorithm.Now the accuracy of Weigh-in-Motion system still needs to be improved.This paper designs and implements Weigh-in-Motion system based on piezo-film;analyzes the influence of piezo-film sensor and Weigh-in-Motion algorithm on the accuracy of Weigh-in-Motion system.Firstly,aiming at the accuracy of piezo-film sensor,uses the new sensor embedding method of bracket control and colloidal package and sensor layout method of Z-type to reduce the influence of working environment on its stability and sensitivity,and improve the credibility of experimental results.Secondly,aiming at the performance of the Weigh-in-Motion algorithm,detects the point of the weighing signal by the method of wavelet transform modulus maxima,then calculates the area of the weighing signal and the speed of the vehicle by the point,which improve the accuracy of the algorithm;in addition,considers the influence of ambient temperature to the sensitivity of piezo-film sensor,and proposes a dynamic weighing coefficient based on temperature to compensate the sensitivity of symmetrical algorithm.Finally,tests the accuracy of the algorithm by experiment.The experimental results show that the improved algorithm can reduce theinfluence of ambient temperature and vehicle speed.The weighing error is controlled within 4%,and the average weighing error can be reduced by22.28%.Weighing accuracy meets the accuracy requirements of the IV class weighing system according to ASTM E1318-90.