Distributed mesh topology structure axle counting system and implementation method thereof

Abstract

The invention provides a distributed mesh topology structure axle counting system and an implementation method thereof, and the system comprises a sensor module which is used for detecting the magnetic field change or mechanical vibration generated when wheels pass through a vehicle sensor; the data acquisition module is used for acquiring the detected data; the communication module is used for realizing data transmission and exchange among the nodes; the processing and operation module is used for receiving and processing data from the data acquisition module; according to the distributed axle counting system, the distributed mesh topology structure axle counting system is adopted, axle counting special cables used by the distributed star-shaped step-extension structure axle counting system can be greatly reduced, the construction cost is reduced, the axle counting operation unit extension set is arranged near each sensor, and the measurement accuracy of the axle counting operation unit extension set is improved. And a distributed layout is adopted, so that the risk of paralysis of the whole axle counting system caused by a single-point fault is avoided, and the accuracy and the reliability of the system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of railway signal systems, and in particular to a distributed mesh topology structure axle counting system and an implementation method thereof. Background Art

[0002] When the railway signal system is used in urban rail transit, its equipment is usually composed of multiple stations with an interlocking system concentration area to centrally place the equipment. In this way, an urban rail line will be composed of several interlocking concentration areas, and the axle counting equipment is also placed in a station selected in the interlocking concentration area. Because the axle counting system adopts a distributed star topology, that is, one track section uses one axle counting operation unit, and the detection points involved in the track section adopt a point-to-point connection method.

[0003] At the same time, all axle counting units in the interlocking centralized area are concentrated in a certain interlocking centralized station. In order to ensure the continuity of the axle counting system in the interlocking divided area, two axle counting sensors must be installed in the interlocking divided area. The two sensors send signals to the axle counting devices in the interlocking centralized areas at both ends. This will add an extra sensor and related construction in the interlocking divided area. In order to ensure the continuity of the axle counting system in the interlocking divided area, corresponding signal machines must be added at the divided area of ​​the interlocking system. With such a structure, the number of signal machines and their supporting cables and construction work are invisibly increased during engineering design and construction, and there is a risk of paralysis of the entire axle counting system due to a single point failure.

[0004] Therefore, it is necessary to provide a new distributed mesh topology axle counting system and an implementation method thereof to solve the above technical problems. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a distributed mesh topology structure axle counting system and an implementation method thereof.

[0006] A distributed mesh topology axle counting system includes a sensor module, which is used to detect magnetic field changes or mechanical vibrations generated when wheels pass through the sensor module, and convert the process of train wheels passing through the sensor module into an identifiable electrical signal;

[0007] A data acquisition module, used for collecting data detected by the sensor module;

[0008] The processing and calculation module is used to receive and process the data collected by the data acquisition module;

[0009] The processing and calculation module includes a microprocessing unit and an axle counting calculation unit. The microprocessing unit receives the digital signal from the data acquisition module and processes the digital signal from the data acquisition module.

[0010] The axle counting unit includes several axle counting unit extensions, and each axle counting unit extension only completes the calculation of the number of wheels above the sensor connected to it. The axle counting unit extension outputs the information it obtains to the interlocking system through an interface, and each axle counting unit extension shares the information on the sensors connected to it, and one track section uses one axle counting unit;

[0011] Power module, used to provide power support for each module of the entire axle counting system;

[0012] The display and monitoring module is used to display the basic data of the current axle counting system and transmit the data of the axle counting system to a remote monitoring center through a communication network.

[0013] Furthermore, the axle counting operation unit extension is meshed through cables, optical fibers or fast Ethernet, and is connected to the interlocking system through a relay interface or an electronic interface through an axle counting operation unit extension that is close to the interlocking system.

[0014] Furthermore, each axle counting unit extension in the axle counting unit can share the number of wheels passing through the respective sensors, information on whether there is a vehicle occupying the section, reset information of the axle counting section collected by the interlocking system in the railway signal system, and fault information.

[0015] Furthermore, each axle counting operation unit extension shares the information of the sensors connected to it through the transmission channels between the axle counting operation unit extensions.

[0016] Furthermore, the sensor module includes a spoke-type electromagnetic sensor or a rim-type electromagnetic sensor, and the sensor module transmits the electrical signal to the axle counting operation unit extension through the data acquisition module.

[0017] Further, the data acquisition module includes a signal conditioning unit and a data acquisition unit;

[0018] The signal conditioning unit amplifies the original signal generated by the wheel sensor and removes the noise mixed in the wheel sensor signal through the filtering circuit;

[0019] The data acquisition unit converts the electrical signal processed by the signal conditioning unit into a digital signal, samples the analog signal according to the sampling frequency, and the collected digital signal is temporarily stored in a buffer inside the data acquisition unit.

[0020] Furthermore, the microprocessing unit receives the digital signal from the data acquisition module, and determines the number of axles of the train by counting the pulse signal pairs. At the same time, it determines the direction of travel of the train by analyzing the sequence of signals from different sensors, and then calculates the speed of the train by combining the axle number information and time information through the microprocessing unit.

[0021] Furthermore, the digital signal includes the time when the wheel passes the sensor and the number of pulses.

[0022] Furthermore, it also includes a communication module for realizing data transmission and exchange between nodes;

[0023] The present invention also provides a method for implementing a distributed mesh topology axle counting system, comprising the following steps:

[0024] S1. System planning and design: First, clarify the application scenario of the axle counting system, then build a distributed mesh topology, determine the location of each axle counting node, and select appropriate wheel sensors;

[0025] S2. Hardware installation and configuration: Install wheel sensors at the rails and install data acquisition units along the railway.

[0026] S3, software programming: write data acquisition programs to collect and digitize sensor signals;

[0027] S4. According to the arrangement of the wheel sensors on site, a set of axle counting operation unit extensions is placed near each wheel sensor. Each axle counting operation unit extension is meshed through cables, optical fibers or fast Ethernet. A certain axle counting operation unit extension close to the interlocking system is connected to the interlocking system using a relay interface or an electronic interface. Each axle counting operation unit extension shares the axle number information, reset information and fault information collected above the sensor connected to it through the transmission channel between them.

[0028] S5. System testing and optimization: Comprehensively test each function of the axle counting system, and test the accuracy, reliability and stability of the system;

[0029] S6. Operation, maintenance and management: During normal operation of the system, the system's working status is monitored in real time through the monitoring software, and the data generated by the axle counting system is effectively managed. Compared with the related art, the distributed mesh topology axle counting system and its implementation method provided by the present invention have the following beneficial effects:

[0030] 1. The present invention adopts a distributed mesh topology axle counting system. When it uses the ring network laid along the railway or between interlocking centralized stations, it can greatly reduce the axle counting special cables used in the distributed star topology axle counting system, reduce the construction cost, and at the same time save a sensor and corresponding cables and construction in the interlocking partition area. In addition, it can also meet the demand of not setting sensors and signal machines in the interlocking partition area.

[0031] 2. The present invention adopts a decentralized layout by placing an axle counting unit extension near each sensor, thereby avoiding the risk of the entire axle counting system being paralyzed due to a single point failure and improving the accuracy and reliability of the system in complex environments and with multiple devices working together.

[0032] 3. In the present invention, when the interlocking system sends a reset command to the axle counting system, the axle counting operation unit extension connected to the interlocking system shares the information with other axle counting operation unit extensions, and all axle counting extensions complete the reset operation at the same time. Each axle counting operation unit extension synchronizes its own judgment on whether there is vehicle occupancy information. When the judgment is inconsistent, the axle counting operation unit extension enters the occupied state, effectively reducing the extension of the train running interval caused by the reset delay and ensuring the efficient flow of railway transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A flowchart of a distributed mesh topology axle counting system provided by the present invention;

[0034] Figure 2 A structural block diagram of a distributed mesh topology axle counting system provided by the present invention;

[0035] Figure 3 A schematic diagram of the working principle of a distributed mesh topology axle counting system provided by the present invention;

[0036] Figure 4 A schematic diagram of a distributed mesh topology axle counting system provided by the present invention for multiplexing sensors in interlocking partition areas;

[0037] Figure 5 A schematic diagram of a distributed mesh topology axle counting system provided by the invention for application between interlocking centralized stations;

[0038] Figure 6 A flowchart of a method for implementing a distributed mesh topology axle counting system provided by the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0040] In the specific implementation process, Figure 1As shown, a sensor module is included, which is used to detect the magnetic field changes or mechanical vibrations generated when the wheels pass through the sensor module, and convert the process of the train wheels passing through the sensor module into an identifiable electrical signal.

[0041] The sensor module is a wheel sensor, which uses a spoke-type electromagnetic sensor or a rim-type electromagnetic sensor. It uses the electromagnetic principle to convert the process of the train wheel passing through the sensor into an identifiable electrical signal in a contactless manner, and transmits the electrical signal to the axle counting unit extension. The axle counting unit extension completes the evaluation of the number of wheels passing above the sensor. Specifically, when the wheel passes through the sensor, it can generate a corresponding signal change. When the wheel approaches, the electromagnetic induction sensor will change the surrounding magnetic field due to the metal material of the wheel, thereby generating an induced electromotive force in the sensor coil and generating a pulse signal. This pulse signal represents the event of the wheel passing through, providing basic data for subsequent axle counting operations.

[0042] In addition to simple wheel passing detection, the sensor module can also be used to obtain wheel passing time information and accurately record the time when each pulse signal is generated, which is essential for calculating the train speed and determining the train's direction of travel. Sensors are usually installed on the inside of the rail near where the wheels pass. For double-track railways, sensors must be installed on each track, and the accuracy and consistency of the installation position must be guaranteed. During the installation process, the sensor must maintain a good fit with the surface of the rail to avoid looseness or displacement. The embedded installation method is used to embed the sensor part into the rail so that it is flush with the rail surface, which does not affect the normal operation of the train and can ensure accurate detection of the wheel.

[0043] The data acquisition module is used to collect the data detected by the sensor module, wherein the data acquisition module includes a signal conditioning unit and a data acquisition unit, the signal conditioning unit is used to process the electrical signal transmitted by the sensor module, and the data acquisition unit is used to digitally collect the conditioned electrical signal. The data detected by the vehicle sensor includes wheel passing information, wheel physical property related data, and train running status related data.

[0044] The signal conditioning unit amplifies the original signal generated by the wheel sensor and removes the noise mixed in the wheel sensor signal through the filtering circuit. At the same time, in order to prevent external interference signals from affecting other parts of the axle counting system through the sensor line, the signal conditioning unit will perform signal isolation.

[0045] The signal conditioning unit comprises an amplifier circuit, a filter circuit and an isolation circuit.

[0046] The amplifier circuit is composed of an operational amplifier, which can be configured as a common-phase amplifier or an inverting amplifier as needed. The output signal of the common-phase amplifier is in phase with the input signal, and the amplification factor is calculated as follows:

[0047]

[0048] In the formula, A is the magnification, R is f is the feedback resistor, R i is the input resistance;

[0049] The output signal of the inverting amplifier is inverted to the input signal, and the formula for calculating its amplification factor is:

[0050]

[0051] In the actual signal conditioning unit, the appropriate amplifier circuit configuration is selected according to the characteristics of the sensor signal and the required amplification factor, and high-precision resistors are used to ensure the accuracy of the amplification factor;

[0052] The filter circuit is composed of components such as capacitors, inductors and resistors. A first-order low-pass filter can be composed of a resistor R and then a capacitor C. Its cut-off frequency formula is:

[0053]

[0054] By choosing the appropriate resistor and capacitor values, the filter cutoff frequency can be determined;

[0055] The isolation circuit is composed of a light-emitting diode and a phototransistor. When the input signal makes the light-emitting diode emit light, the phototransistor receives the light signal and turns on, thereby realizing the isolated transmission of the signal. In the signal conditioning unit, the isolation circuit can effectively prevent external interference from entering the core part of the system, and also protect the system from damage caused by abnormal conditions such as high voltage that may occur on the sensor line.

[0056] The data acquisition unit converts the analog signal processed by the signal conditioning unit into a digital signal, samples the analog signal at a certain sampling frequency, and the collected digital signal is temporarily stored in a buffer inside the data acquisition unit.

[0057] The structure of the data acquisition unit includes an analog-to-digital converter chip, a sampling and holding circuit, and a control logic circuit; the analog-to-digital converter chip is the core component of the data acquisition unit, and there are many types to choose from. The performance parameters of the analog-to-digital converter chip include resolution, conversion speed, and input range; the sampling and holding circuit samples the analog signal under the control of the sampling instruction, and keeps the signal amplitude at the sampling moment for a period of time to ensure that the analog-to-digital converter can accurately convert. The working principle of the sampling and holding circuit is to store the analog signal voltage at the sampling moment through a capacitor, and then provide this voltage to the analog-to-digital converter for conversion during the holding stage; the control logic circuit is responsible for coordinating the entire data acquisition process. It generates a sampling pulse signal to control the operation of the sampling and holding circuit, and also controls the start-up of the analog-to-digital converter and the reading of the digital signal after the conversion is completed. The control logic circuit can be programmed to implement different sampling modes and control strategies to meet the needs of different axle counting systems.

[0058] The communication module is used to realize data transmission and exchange between nodes; the performance indicators and requirements of the communication module include transmission rate, transmission distance, anti-interference ability, reliability and stability.

[0059] The processing and calculation module is used to receive and process the data from the sensor module, and perform complex logical operations to determine the passing of the train, and perform operations on the received signals.

[0060] Among them, the processing and calculation module includes a microprocessing unit and an axle counting calculation unit. The microprocessing unit receives the digital signal from the data acquisition module, and the microprocessing unit processes the digital signal from the data acquisition module according to a pre-programmed algorithm. The microprocessing unit receives the digital signal from the data acquisition module, and determines the number of axles of the train by counting the pulse signal. At the same time, the direction of travel of the train is determined by analyzing the sequence of signals from different sensors, and then the microprocessing unit can calculate the speed of the train by combining the axle number information and time information; the microprocessing unit consists of a microprocessing unit chip, a storage unit and an interface circuit.

[0061] The microprocessor chip is the core component of the microprocessor. Common chips include ARM architecture and x86 architecture. ARM architecture chips are widely used in embedded systems due to their low power consumption and high performance. The performance parameters of the microprocessor chip include clock frequency, number of cores and instruction set; the storage unit includes random access memory and read-only memory. The random access memory is used to store temporary data during program operation, such as collected signal data and intermediate variables in the calculation process. The read-only memory is used to store program code and some fixed data, such as system initialization parameters and sensor calibration data; interface circuit, the microprocessor is connected to other modules through the interface circuit. Common interfaces include universal serial bus interface, serial communication interface and parallel interface.

[0062] like Figure 2 As shown, the axle counting operation unit includes several axle counting operation unit extensions, and each axle counting operation unit extension only completes the calculation of the number of wheels above the sensor to which it is connected, and provides working power to the sensor; the axle counting operation unit extension outputs the information it obtains to the interlocking system through an interface, and each axle counting operation unit extension shares the information on the sensors connected to each other through a transmission channel. Specifically, each axle counting operation unit extension in the axle counting operation unit can share the number of wheels passing through their respective sensors, the information on whether there is a vehicle occupying the determined section, the reset information of the axle counting section collected by the interlocking system, and the fault information.

[0063] It should be noted that the axle counting unit and the data acquisition module have an interactive relationship. The axle counting unit relies on the signals provided by the data acquisition module. The data acquisition module transmits the digital signals after signal conditioning to the axle counting unit. The quality of these signals directly affects the calculation results of the axle counting unit.

[0064] The interactive relationship between the axle counting unit and the communication module. The number of axles, driving direction and speed information calculated by the axle counting unit need to be transmitted to other devices or monitoring centers through the communication module. The communication module is responsible for packaging these data and sending them to the designated destination.

[0065] At the same time, each axle counting operation unit extension has the function of judging whether there is a vehicle occupying the same axle counting section and can output the information to the interlocking system through the relay interface or the fully electronic interface; each axle counting operation unit extension has the function of collecting the reset information of the interlocking system for the axle counting section; each axle counting operation unit extension has the function of networking with each other through cables, optical fibers, and fast Ethernet as transmission channels, and the channels are redundant channels, and redundancy functions can also be completed between different types of channels; each axle counting operation unit extension has the function of forwarding data from other axle counting operation unit extensions; each axle counting operation unit extension has the function of self-fault diagnosis and the function of sensor fault diagnosis.

[0066] The axle counting system uses point-to-point cable connection between sensors and axle counting computing units, and optical fiber or network connection between axle counting computing units. One axle counting computing unit is used for one track section. In this way, one axle counting unit is composed of several axle counting computing units, and a mesh topology is formed between the axle counting computing units. Each axle counting computing unit can independently output the idle / occupied information of the axle counting section, collect reset information, and the axle counting computing units share the sensor axle number information and reset information processed by each of them. There is no host or slave setting. When the axle counting system with this mesh topology structure uses the ring network that has been laid along the railway or between interlocking centralized stations, it can greatly reduce the axle counting special cables used in the distributed star-type extension step structure axle counting system, reduce the construction cost, and at the same time save a sensor and corresponding cables and construction in the interlocking partition area. In addition, it can also meet the needs of not setting sensors and signal machines in the interlocking partition area.

[0067] like Figure 3 As shown in the figure, the working principle of the axle counting system is as follows; according to the arrangement of sensors in the axle counting section on site, a set of axle counting operation unit extensions are placed near each sensor, and the axle counting operation unit extensions are meshed through cables, optical fibers or fast Ethernet, and are connected to the interlocking system through a relay interface or an electronic interface through an axle counting operation unit extension that is close to the interlocking system. Each axle counting operation unit shares the axle number information, reset information and fault information collected above the sensor connected to it through the transmission channel between them. At this time, any axle counting operation unit extension knows the number of wheels passing through all the entrances and exits of the axle counting section where it is located. At this time, as long as it is determined that the axle counting section is due to the number of wheels passing through the entrance and all the exits. If the information is not consistent, it can be known whether the axle counting section is occupied by a vehicle, and then the relay can be driven or the data output can be completed through the safety code and the interlocking system. Similarly, when the interlocking system sends a reset command to the axle counting system, the axle counting operation unit extension connected to the interlocking system shares the information to other axle counting operation unit extensions, and all axle counting extensions complete the reset operation at the same time. Each axle counting operation unit extension synchronizes its own judgment on whether there is a vehicle occupied. When the judgment is inconsistent, the axle counting operation unit extension enters the occupied state to improve the system safety. When any axle counting operation unit extension in the system fails, the information is shared with several other unit extensions, and other axle counting operation unit extensions will guide the axle counting section to be occupied, completing the fault-guided safety function.

[0068] Figure 4 and Figure 5 They are the practical applications of the axle counting system, Figure 4 For the axle counting system, multiplexing the sensors in the interlocking partition area. Figure 5 It is used for axle counting system between interlocking centralized stations.

[0069] like Figure 4 As shown, one axle counting sensor can be used in the interlocking partition area, and the axle number information of the axle counting sensor is shared with the axle counting unit extension in the interlocking central area on the right through the axle counting operation unit extension in the interlocking central area on the left. Therefore, the sensor connected to the interlocking central station on the right side in the existing axle counting system in the interlocking partition area can be cancelled, saving the sensor and its related cables and construction.

[0070] like Figure 5 As shown, when the railway transportation volume is relatively low, the axle counting section between the interlocking concentration stations A and B can be cancelled. The J1 sensor and the J2 sensor constitute an axle counting section. The axle number information of the J1 / J2 sensors are shared by the two axle counting operation unit extensions to form a complete axle counting section. The two sensors and signal machines at the interlocking division area are cancelled, saving the sensors and signal machines and their related cables and construction.

[0071] In addition, the system also includes a power module, which is used to provide power support for each module of the entire axle counting system; the stability of the power module is crucial to the stable operation of the entire axle counting system. The railway environment is complex and changeable, and there are various interference factors, such as electromagnetic interference and voltage fluctuations.

[0072] It also includes a display and monitoring module, which is used to display the basic data of the current axle counting system and transmit the data of the axle counting system to a remote monitoring center through a communication network; the display and monitoring module is composed of a display device and a monitoring software system; the display device can be a liquid crystal display, a light-emitting diode display or other types of electronic display screens; the bottom layer of the monitoring software system is a data receiving and processing module, which is responsible for receiving data from each axle counting node through the communication module. These data may be in different formats and need to be parsed and preprocessed to convert them into a format that the software can recognize and process.

[0073] like Figure 6 As shown, the present invention also provides a method for implementing a distributed mesh topology axle counting system, comprising the following steps:

[0074] S1. System planning and design: First, the application scenario of the axle counting system needs to be clarified, and then a distributed mesh topology structure is constructed to determine the location of each axle counting node and select appropriate wheel sensors;

[0075] S2. Hardware installation and configuration: Install wheel sensors at appropriate locations on the rails and data acquisition units at appropriate locations along the railway;

[0076] It should be noted that at a curve, the running track of the train wheels will change, so the installation angle of the sensor needs to be adjusted according to the curvature of the curve;

[0077] S3, software programming, writing data acquisition programs to realize the collection and digitization of sensor signals;

[0078] It should be noted that when writing the data acquisition program, first, you need to write code to read the vehicle sensor signal and configure the corresponding communication parameters according to the interface type between the data acquisition device and the sensor;

[0079] S4. According to the arrangement of the wheel sensors on site, a set of axle counting operation unit extensions is placed near each wheel sensor. Each axle counting operation unit extension is meshed through cables, optical fibers or fast Ethernet. A certain axle counting operation unit extension close to the interlocking system is connected to the interlocking system using a relay interface or an electronic interface. Each axle counting operation unit extension shares the axle number information, reset information and fault information collected above the sensor connected to it through the transmission channel between them.

[0080] S5. System testing and optimization: Comprehensively test each function of the axle counting system, and test the accuracy, reliability and stability of the system;

[0081] S6. Operation, maintenance and management: During the normal operation of the system, the system's working status is monitored in real time through the monitoring software, and the data generated by the axle counting system is effectively managed;

[0082] It should be noted that when monitoring the operation of the system, the real-time data generated by the axle counting system is continuously monitored through the monitoring software, and a data anomaly detection mechanism is established to determine whether the data is abnormal by setting thresholds and rules.

[0083] The circuits and controls involved in the present invention are all prior art and will not be described in detail here.

[0084] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A distributed mesh topology axle counting system, characterized in that: It includes a sensor module, which is used to detect the magnetic field change or mechanical vibration generated when the wheels pass through the sensor module, and convert the process of the train wheels passing through the sensor module into an identifiable electrical signal; A data acquisition module, used for collecting data detected by the sensor module; The processing and calculation module is used to receive and process the data collected by the data acquisition module; The processing and calculation module includes a microprocessing unit and an axle counting calculation unit. The microprocessing unit receives the digital signal from the data acquisition module and processes the digital signal from the data acquisition module. The axle counting operation unit includes a plurality of axle counting operation unit extensions, and each axle counting operation unit extension only completes the calculation of the number of wheels above the sensor connected to it, and the axle counting operation unit extension outputs the information obtained to the interlocking system through an interface, and each axle counting operation unit extension shares the information on the sensors connected to each other, and one axle counting operation unit is used for one track section; Power module, used to provide power support for each module of the entire axle counting system; The display and monitoring module is used to display the basic data of the current axle counting system and transmit the data of the axle counting system to a remote monitoring center through a communication network.

2. The distributed mesh topology axle counting system according to claim 1, characterized in that: The axle counting operation unit extension is meshed through cables, optical fibers or fast Ethernet, and is connected to the interlocking system through a relay interface or an electronic interface via an axle counting operation unit extension that is close to the interlocking system.

3. The distributed mesh topology axle counting system according to claim 2, characterized in that: Each axle counting unit extension in the axle counting unit can share the number of wheels passing through the respective sensors, the information on whether there is a vehicle occupying the section, the reset information of the axle counting section by the interlocking system in the railway signal system, and the fault information.

4. The distributed mesh topology axle counting system according to claim 3, characterized in that: Each axle counting computing unit extension shares each piece of information on the sensors connected to it through the transmission channels between the axle counting computing unit extensions.

5. The distributed mesh topology axle counting system according to claim 4, characterized in that: The sensor module includes a spoke-type electromagnetic sensor or a rim-type electromagnetic sensor, and the sensor module transmits an electrical signal to an axle counting operation unit extension through a data acquisition module.

6. The distributed mesh topology axle counting system according to claim 1, characterized in that: The data acquisition module includes a signal conditioning unit and a data acquisition unit; The signal conditioning unit amplifies the original signal generated by the wheel sensor and removes the noise mixed in the wheel sensor signal through a filtering circuit; The data acquisition unit converts the electrical signal processed by the signal conditioning unit into a digital signal, samples the analog signal according to the sampling frequency, and the collected digital signal is temporarily stored in a buffer inside the data acquisition unit.

7. The distributed mesh topology axle counting system according to claim 1, characterized in that: The microprocessing unit receives the digital signal from the data acquisition module, and determines the number of axles of the train by counting the pulse signal pairs. At the same time, it determines the direction of travel of the train by analyzing the sequence of signals from different sensors, and then calculates the speed of the train by combining the axle number information and time information.

8. The distributed mesh topology axle counting system according to claim 7, characterized in that: The digital signal includes the time when the wheel passes the sensor and the number of pulses.

9. The distributed mesh topology axle counting system according to claim 1, characterized in that: It also includes a communication module for realizing data transmission and exchange between nodes.

10. A method for implementing a distributed mesh topology axle counting system according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. System planning and design: First, clarify the application scenario of the axle counting system, then build a distributed mesh topology, determine the location of each axle counting node, and select appropriate wheel sensors; S2. Hardware installation and configuration: Install wheel sensors at the rails and install data acquisition units along the railway. S3, software programming: write data acquisition programs to collect and digitize sensor signals; S4. According to the arrangement of the wheel sensors on site, a set of axle counting operation unit extensions is placed near each wheel sensor. Each axle counting operation unit extension is meshed through cables, optical fibers or fast Ethernet. A certain axle counting operation unit extension close to the interlocking system is connected to the interlocking system using a relay interface or an electronic interface. Each axle counting operation unit extension shares the axle number information, reset information and fault information collected above the sensor connected to it through the transmission channel between them. S5. System testing and optimization: Comprehensively test each function of the axle counting system, and test the accuracy, reliability and stability of the system; S6. Operation, maintenance and management: During normal operation of the system, the system's working status is monitored in real time through the monitoring software, and the data generated by the axle counting system is effectively managed.

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