The Design Of Embedded Rail Vibration Monitoring Node

With the universal speed-up of rail transport as well as new high-speed train emerging, due to the limitations of its factors, the traditional railway track inspection method with large flaw detection cars and small flaw detector, has been unable to meet the security needs of the high-speed rail development. Over the years, vibration measurement and signal analysis as a major failure prediction and repair method has been successfully applied to a variety of industrial fields, but the use of railway safety testing is still in the stage of basic research. Therefore, how to use the vibration signal to find a new rail flaw detection mode, and achieve real-time online monitoring the status of railroad rails, has been an important research topic in the field of railway safety testing. In recent years, the rapid development of wireless communication technology, embedded technology and signal processing technology, makes obtaining a large number of experimental data on the rail vibration characteristics and rail state real-time monitoring possible. This paper designed and implemented embedded rail vibration monitoring node based on Zigbee wireless communication technology and embedded technology. The node has real-time, timing and trigger three acquisition modes, can be realized large amounts of data collection, storage, processing and transmission functions via the remote control.This paper designed multiple range difference input channel amplification regulate circuit; Built a second-order Butterworth low-pass filter circuit for hardware anti-aliasing filtering; Utilized sigma-delta24bit high-precision ADC for the voltage signal quantization and acquisition to ensure the accuracy and resolution of node sampling; Used STM32F103VE microprocessor based on the Cortex-M3architecture as control core. With the aid of large-capacity NAND flash memory chips and high gain Zigbee module to achieve the data collection, storage, processing and wireless transmission.On the basis of the design of basic data collection, storage, handling and transfer programs, adding a FIR low-pass digital filter and data re-sampling algorithm, to compensate for the lack of second-order Butterworth low-pass hardware filter, reducing the hardware circuit design complexity and production costs; Proposed "First stored data before the processing" program scheme, in higher-order digital filter to reduce the signal amplitude attenuation and narrow bandwidth, at the same time effectively alleviate the pressure of the FIR filter to the processor; In remote firmware upgrade program for software remote maintenance and extensions, improved traditional updated guide mechanism, and took full advantage of the variety of hardware aborts of the processor for the updated boot exception handler to enhance the reliability of remote firmware upgrade program; Used the wireless transmission of data loss supplement package policies, with improved data frame format, further ensured the integrity of data transmission.The laboratory test and field experiments show that node comprehensive performance has achieved initial design goal, has a certain anti-jamming ability and expansibility, is appropriate for rail vibration online monitoring and has great significance for further research and application of rail dynamic performance by provided a large number of basic data on rail dynamic characteristics analysis.