| China's railway transport is currently an important link in the lifeline of the national economy,its safety is related to the lives and interests of every one of us.The rail is exposed to the open air for a long time,which is easy to break under the rolling of locomotive wheels.Therefore,how to improve the real-time,accuracy and stability of rail breaking detection is an important research topic.This paper presents a real-time ultrasonic track breaking detection system based on multi-core DSP.According to the characteristics of ultrasonic guided wave propagation,in order to solve the problem of low range resolution in traditional monopulse excitation detection,Barker code in two-phase coding is introduced as the transmitting signal modulation method to improve the average power of the transmitting signal.According to the characteristics of multi-core DSP,a signal processing mode of multi-algorithm and multi-core parallel processing is proposed.First of all,in order to ensure the characteristic signal resolution in the long distance detection,matching filter is chosen as the pulse compression method for processing of received signal,.Its feasibility is validated by Matlab simulation analysis for the results of the pulse compression distance sidelobe problems could affect the test result,of matched filter and window function and put forward improving two methods sidelobe suppression.The characteristics and simulation results of different window functions were compared by Matlab.Blackman window was selected as the window adding method.By comparing the side lobe suppression effect of the weighted matched filter and the least square inverse filter,the weighted matched filter is selected as the improved matched filter.In the simulation environment,the peak value of the main lobe was almost unaffected by the improved pulse compression results,and the peak value of the side lobe was reduced by 28.14dB.Secondly,considering the impact of rail break detection on the passing of trains,in order to further increase the real-time performance and reliability of the whole system,an energy spectrum analysis algorithm is proposed to process signals to assist the detection and judgment of rail break.Finally,combined with the pulse compression algorithm and the energy spectrum analysis algorithm,a signal processing mode for the parallel processing and analysis of the received signal is designed to detect the broken orbit.The software and hardware design of the system is completed,and field experiments are carried out.The experimental results show that the pulse compression algorithm can effectively improve the amplitude and detection resolution of the ultrasonic guided wave receiving characteristic signals.Combined with the energy spectrum analysis,it can effectively determine in real time which state the orbit is idle,occupied or broken. |
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