Research On Data Processing System Of Electromagnetic Rail Flaw Detection

In the research of rail flaw detection system, the acquisition and processing of sensor's signal is the main content to be researched in this field. In order to locate the flawed rail correctly, the synchronous signal of the coil need to be exquisite correctly and do some real-time processing, because the acquisition density of the coil signal is large and the acquisition speed is high, a lot of problems are carried out in the rail flaw detection in electromagnetic system with the development of electronic technology, FPGA devices are becoming more and more popular. With the properties of high frequency clock, low inner delay, flexible programming mode and parallel processing mode, FPGA devices has become the ideal platform to deal with data processing of rail flaw detection.This thesis mainly discuss the design flow of data processing system based on FPGA, by combine the FPGA technology with electromagnetic flaw detection, a lot of problems on rail flaw detection are solved, and the system's properties of real-time, reliable and speed are improved as well. The main content of the paper is shown as below:1. This thesis points out the theory of spectrum analysis, fast coherent rule and least square method, it also presents the analysis and comparison of the performance of those three methods when the system is under an interruption with noise.2. The model of electromagnetic detection's data processing system based on FPGA is constructed. XILINX ISE design tools and Verilog are chosen to complete the blocks of signal acquisition, signal processing, signal decoding and data output to fulfill the entire FPGA design flow. With the consideration of decoding algorithm's resources consumption and calculation period, in order to choose a proper algorithm in data decoding system, the difficulties and feasibilities of spectrum analysis and fast coherent when they are fulfilled in FPGA will be verified in the thesis.3. The performance of every block of the system will be presented in this thesis, Modelsim and System Generator is chose to do the simulation. Then the system is implemented on the XILINX Virtex-5XC5VLX110T board. The analysis of the performance of the whole system will be verified in the end.With the help of combination of the computer simulation and FPGA design technology, the design of the proto model and verification of the system can be accelerated. The decoding algorithm with large amount of calculation and powerful real-time in hardware can be fulfilled conveniently and the conclusion is:the system has the properties of high speed and strong control ability, it can meet the requirement of rail flaw detection.