Design Of The Ultrasonic Guided Waves Broken Rail Detection System Integrated Track Circuit Mode

The rail is exposed to open air for a long time and subjected to repeated rolling of the locomotive wheels,which is prone to breakage.Experts and scholars in related fields have studied and put forward many theories and implementation methods for broken rail detection,but each of these methods has their own limitations.Therefore,two or more types of broken track detection methods are combined,making their advantages complementary,which has a good engineering application prospect.Ultrasonic guided waves broken rail detection method has the characteristics of being free from the impact of ballast bed,environment and electromagnetics,and low cost,but it can not be used to detect the interval with rail joints.In addition,the occurrence of rail joints in the current railway lines is uncertain,which limits its scope of application;Track circuit broken rail detection method can be used to perform the broken rail detection in the interval with rail joints,because of the transmission of electrical signals in the rail.But the cost is high and it is easily affected by environmental factors.Therefore,integrating the track circuit into the ultrasonic guided waves broken rail detection system can exert its own advantages and be suitable for complex on-site conditions,which is more conducive to engineering promotion.In this paper,based on the original ultrasonic guided waves broken rail detection system in our laboratory,some circuits and detection algorithms is improved,and the designed track circuit broken rail detection system is integrated with it,and then ultrasonic broken rail detection system of integrated track circuit method is designed.In order to combine the two types of broken rail detection methods,a special ultrasonic guided waves transducer is customized.The metal shell of transducer is used to transmit electrical signals,so that only the switches on the circuit board is simply controlled and then the two types of detection can be performed,which can avoid the secondary construction.In the interval of 1km along the railway line,the broken rail detection transceiver device is installed in sequence,and different detection methods are selected according to whether or not there is a rail joint in the section.In the corresponding detection method,the ultrasonic guided waves signal or electric signal with certain characteristics is emitted by the launch device.The receiving device performs feature extraction for the received signal,and identifies it by the detection algorithm,and then determines the direction of the signal.If a certain side signal is not identified for a long time,it is considered that there is a broken rail in this side section,and then the broken rail warning message will be sent to the server.Among them,the transmitted ultrasonic guided waves signal is generated by the pulse transformer booster excitation transducer,and the electrical signal is generated by BPSK modulation using the Kasami pseudo-random sequence code and sinusoidal carrier signal.After the two signals are transmitted through the rail,they are collected and identified by the ARM processor.After completing the hardware and software design of the system,a large number of experiments are conducted on the railway site.Through the experimental verification,the two types of broken rail detection methods in the system are easy to switch,which can accurately identify the rail fracture,have high recognition rate,meet the requirements of on-site use and can perform real-time broken rail detection without interruption.