Study on weigh-in-motion system based on chirped fiber gratings

Abstract

A novel weigh-in-motion (WIM) system used for high way is developed based on Chirped fiber Bragg gratings (CFBG) in this paper. The WIM system consists of four CFBG pressure sensors, each of which contains a couple of CFBG. The sensor can directly output optical intensity signal, so the postprocessor instrument is simple and cheap instead of expensive wavelength demodulation apparatus. Theoretical and experimental results indicate that output optical intensity of the sensor is linearly proportional to the pressure, and the linearity and the repeated error can respectively reach to 0.9997 and 0.05%FS. We have also exceeded series experiments with several kinds of automobile with different velocity, and received good results of relative error below 5%.