Design And Implementation Of The Multiplexed Control System For The Ultrasonic Detection Of The Track Slab Structure In High-Speed Railway

The detection of hidden dangers inside the unballasted track slab structure in the high-speed railway provides technical support for the health management and maintenance of the line.From the perspective of avoiding the impact of the reinforcement structure in the track slab on the detection results,the ultrasonic detection technology has significant advantages.Ultrasonic detection uses artificially excited ultrasonic waves to reflect,diffract,scatter and other phenomena at the reflection interface or between structural layers,and reflects the uneven or defective medium structure through waveform records,and make a scientific judgment on whether there are hidden dangers under the plate according to its kinematic or dynamic characteristics.On the basis of studying the geophysical detection background of the multi-layer dielectric structure of the unballasted track slab in the high-speed railway,compared various detection methods and test results,and defines the advantages of the ultrasonic detection;In order to improve the accuracy of ultrasonic detection,referring to the multiple coverage observation system in reflected wave seismic exploration,and taking into account the factors such as detection efficiency and convenient implementation,an array multiplex control system is proposed.On the premise of meeting the requirements of the rapid detection efficiency during skylight period of the high-speed rail line.It simplifies the structural components of signal acquisition and internal control,ensures the stability of the system and facilitates system maintenance.The array multiplex control system is equipped with upper computer,acquisition card,power module,high-voltage transmitting module,communication module,multi-channel main control unit,multi-channel sub control unit,preamplifier module,transducer and so on.The upper computer responds to the user’s instructions and transmits it to the corresponding control conversion port or function module through the control bus or I/O port for execution;The acquisition card completes the functions of signal real-time A/D conversion,transmission and storage;The high-voltage transmitting module uses capacitors for high-voltage storage,carries a monostable trigger circuit,and uses a high-power triode for transmitting control;The multi-channel main control unit and sub control unit select AT89 series single chip microcomputer as the main control chip,and cooperate with MAX487 E transceiver module to establish RS485 communication;The preamplifier selects LF356 and AD603 operational amplifier chips to realize two-stage gain through program control.According to the scheme,the relevant software and hardware design of the control system has been implemented and completed.After joint commissioning and field testing,the whole system can provide reliable basic data guarantee for the rapid detection of hidden dangers of the track slab.