Research Of Optical Fiber Train Axis Counting Technology

In recent years,the modernization of our country's railway is reinforced continually.So we must enhance the efficiency of manoeuvre ulteriorly which is corresponding to the rising power of transport and the requirement.But at present railway signal of our country mainly comes from track circuit and some electromagnetic axis-counting equipments.But traditional track circuit and axis-counting equipment belong to electrical or electromagnetic system.There are many problems in anti-electromagnetic interference,using performance,applying cost and environmental influence to using.So we developed a new-style optical fiber axis counting system which takes optical grating as sensing units and combines optical fiber communicating technology with computer technology.The system transforms the stress of rail to the change of wavelength which is reflected by fiber grating to achieve the aim of axis-counting.Traits of optical fiber are low cost,easy to assemble, small in bulk,high precision,low in additive spoilage,good repeatability,immune to electromagnetic interference.This article introduce rail axis-counting actuality in the world,sensing principle of optical fiber,the mechanical analysis of stress in rail,mechanical design of optical fiber sensor in structure,construction in optical path,data collecting and disposing in the spot and ameliorate of axis-counting program.The work I have mainly done is as following:1.Set up mechanical model of stress of rail and analyze its static dynamics.Affix grating to different places and attain stresses in the different place,validate result of calculate in the theory and confirm the best place of affixed grating. 2.Design the style of sensing base of axis-counting which is fixed on the rail.From all clipping to half clipping to last flat.3.Analyze data from experiment.Attain data from stimulant experiment in lab which include pressure and wavelength shift then make curve related to pressure and wavelength.Optimize the structure of sensor and the method to fix grating.4.Collecting and disposing of the data from the spot.We attained a plenty of data in the applying in trunk line of rail in Beijing-Guangzhou.Analyze many axis-counting wave form of vehicles passing.To those abnormity wave form,we found the method to solve in arithmetic of axis-counting and design of hardware.Now the optical fiber grating axis-counting system can count axis exactly after experiment and improvement.Its performance in applying is good.As the project improve the task constantly,the precision in axis-counting and reliability will advance ulteriorly and become the substitutionary technology of traditional electromagnetic axis-counting equipment.