Signal Acquisition And Development Of Alarm System Of Approaching Train

With the development of science technology and social economy,digital signal acquisition and prototype development have become a key technology,and the emergence of pickup has provided possibility for signal acquisition and development of the train approach warning system.By comparing the advantages and disadvantages of the existing signal acquisition technology in both domestic and foreign train approach warning systems,designed a train approaching alarm system based on wheel-rail sound signal acquisition.This alarm system prototype adopts modular design,has certain anti-interference ability and small volume,and is easy to install and disassemble.Through analyzing wheel-rail sounds generated during train running,this article found that under the different speeds,the train wheel-rail sound components are not the same too.When the train's speed varies between 90 km/h and 140 km/h,the main component of the running train sound is rolling noise generated by interaction between wheel and rails.The MATLAB software is used to analyze the wheel-rail sound signal in both time and frequency domains,and the improved spectral subtraction is used to denoise the wheel-rail noise and get the its pure sound.This article designed the sound signal acquisition warning system.It detects the short-time average energy and the amplitude changes of wheel-rail sound power spectrum at 300 Hz to judge whether the train is approaching.This article has completed the train approaching alarm system hardware design and software simulation.Selected main hardware for alarm system,built with the pickup,signal amplifier and the data acquisition card.This article used virtual instrument platform Lab VIEW to build the simulation software system which includes wheel-rail noise acquisition,analysis,identification and warning functions.It designed the wheel-rail noise processing algorithm through the characteristic parameters of wheel-rail sound in both time and frequency domains,and developed related data collection and data analysis programs.Through the comparison between the original wheel-rail noise and the one after denoising with Lab VIEW,it is realized that the power spectrum of the noise frequency is easy to cause the wrongful train warning,and denoising can improve the reliability and reduce the processing time of early warning judgment,accurately carry on the early warning of train's approach,and construct a more accurate prototype early warning system.