Design Of Railway Axle Counting Safety Hardware Platform

Railway axle counting is currently widely used in the monitoring of the vacancy or occupation status of track sections,and it is also a necessary railway equipment to monitor this state in addition to track circuits.As the track circuit needs to rely on the track as a wire to form loop,under harsh environmental conditions,such as humidity,steel rust,and lightning impact,etc.,it is easy to produce the problems of "red light strip" or poor track shunts,which seriously threaten the safe and normal operation of railways.Even in the zones with better environment,track circuits need constant maintenance,which increases the cost of train operation.The axle counting device is installed at a fixed point on the rail and collects signals by the axle counting sensor.When a wheel passes the sensor,it will change a parameter of the collected signal.According to the changed parameter,the number of axles of the train wheels will be monitored to judge the vacant or occupied state of track section.Although the axle counting device is much less affected by the natural environment than the track circuit,it also has certain defects.First,the electromagnetic induction axle counting sensor is easy to be interfered by the magnetic field around the strong traction current,and the structure of the axle counting sensor is more complicated,which causes difficulties in installation,adjustment and maintenance.Second,the use of axle counting equipment is limited to a certain train operating speed.When the train is running at a high speed,it is easy to lose axles.Finally,when the axle counting system fails to monitor,it needs to be reset manually to make the axle counting equipment not intelligent enough.For the first two major shortcomings of axle counting equipment,the research contents of this article include:(1)Aiming at the shortcomings of the double-sided axle counting sensor based on the principle of electromagnetic induction,this paper designs a simpler axle counting sensor.The finite element simulation tool COMSOL is used to analyze and study the optimal model parameters of the structure sensor.The installation and working methods of the sensor are shown.Experiments show that the sensor can effectively monitor the number of axles,and can effectively identify interference based on signals,which conforms to the requirements of railway equipment safety criterion.(2)Aiming at the defect that axle counting equipment is prone to losing axles on highspeed trains,this article designs a set of axle counting safety hardware platform.When processing axis counting signals,the platform uses FPGA chip as the main control chip for the signal processing board instead of the single-chip microcomputer or single-core DSP.Compared with single-chip or single-core DSP,FPGA chip has obvious advantages,such as fast running speed(parallel execution),strong parameter adjustability,and strong function expandability.The platform uses STM32 chips for signal transmission,data comparison,and control of relays.This article introduces the hardware circuit implementation and software program implementation of the platform.After testing,compared with the previous signal processing system,the platform is suitable for counting faster train axles,and has higher safety and stability.