Method for judging slipping condition exit based on beacon reading

Abstract

The invention discloses a method for judging to quit a slip working condition based on beacon reading, which comprises the following steps of: 1, acquiring position information of a first beacon and a second beacon arranged on a track, and calculating a distance between the first beacon and the second beacon; 2, the pulse type speed sensor obtains the accumulated pulse number at the first beacon and the accumulated pulse number at the second beacon respectively; 3, calculating the minimum pulse distance and the maximum pulse distance between the first beacon and the second beacon according to the accumulated pulse numbers of the first beacon and the second beacon; 4, whether the distance between the first beacon and the second beacon is between the minimum pulse distance and the maximum pulse distance or not is judged, and if the distance between the first beacon and the second beacon is between the minimum pulse distance and the maximum pulse distance, it is judged that the slipping working condition is quitted, and the normal working state is recovered; otherwise, judging that the slip working condition is not quitted. Excessive speed measurement faults and metro braking parking caused by slight slipping are effectively avoided, and the rail transit operation continuity and the system availability are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of rail transit safety technology, and in particular to a method for determining whether to exit a slippage condition based on beacon reading. Background Technology

[0002] In rail transit signaling systems, Odometer Pulse Generators (OPGs) installed on subway wheels are commonly used to measure and calculate the speed of subway vehicles. The principle of pulse speed sensors is to calculate the lateral speed of the train by analyzing the pulses generated by the wheel rotation and combining this with the wheel circumference. However, this method of deriving the train's running speed from the wheel rotation speed needs to consider the phenomenon of wheel slippage when track conditions are poor, causing the wheel speed to not accurately reflect the actual train speed. Generally, abnormal changes in the speed or acceleration calculated by the speed sensor are detected to determine if wheel slippage has occurred. Furthermore, determining when to return to a normal and safe speed measurement state after a wheel slippage abnormality requires a certain voting algorithm.

[0003] Typically, when other speed sensors that do not rely on wheel rotation are available, such as radar or accelerometers, the abnormal state of the wheel slipping can be determined by cross-checking the speed or acceleration data with that speed sensor data.

[0004] However, when vehicle installation conditions are poor, making it impossible to install more sensors or when other sensors are unavailable, relying solely on two pulse speed sensors for mutual verification cannot meet the safety requirements for exiting the slippage state, considering common causes of equipment failure. This would lead to an excessive slippage fault state every time wheel slippage is detected. Even if the actual wheel slippage is only slight and recovers within three or four seconds, the signal system's safety speed measurement system will judge it as slippage that cannot be recovered and enter a speed measurement fault state. This speed measurement fault will cause the speed measurement and positioning function to fail, resulting in the subway braking and stopping, affecting operation and the system's availability. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing rail transit signaling systems, where, when no other speed sensors are available or unavailable, reliance solely on pulse speed sensors for mutual verification results in common-cause failures, failing to meet the safety requirements for judging wheel slippage and affecting operation and system availability. This invention provides a method for judging slippage based on beacon readings. This method involves acquiring the position information of a first and second beacon on the track to calculate their distance, using a pulse speed sensor to obtain the cumulative pulse count at the two beacons, calculating the minimum and maximum pulse distances between the two beacons based on this pulse count, and then determining whether the actual distance between the two beacons falls within these two distances. This achieves the goal of accurately judging train slippage without relying on other speed sensors, avoiding excessive slippage speed measurement failures caused by slight slippage and subway braking stops, and ensuring the operation and availability of rail transit systems.

[0006] The objective of this invention is achieved through the following technical solution: The method for determining whether to exit a slippage condition based on beacon reading includes the following steps: Step 1: Obtain the position information of the first and second beacons set on the track, and calculate the distance between the first and second beacons; Step 2: The pulse velocity sensor acquires the cumulative pulse count at the first beacon and the second beacon, respectively; Step 3: Calculate the minimum pulse distance and maximum pulse distance between the first and second beacons based on the cumulative pulse count at the first and second beacons. Step 4: Determine whether the distance between the first beacon and the second beacon is between the minimum pulse distance and the maximum pulse distance. If it is between the minimum pulse distance and the maximum pulse distance, it is determined that the slippage condition has been exited and the normal working state has been restored; otherwise, it is determined that the slippage condition has not been exited.

[0007] Preferably, at least two pulse speed sensors are provided, and each pulse speed sensor independently executes steps 2 to 4. Normal operation is restored only when all pulse speed sensors determine that the slippage condition has been exited.

[0008] Preferably, step 3 specifically includes: The difference between the cumulative pulse counts at the first and second beacons is the pulse count from the first beacon to the second beacon. The theoretical pulse distance is obtained by dividing the wheel circumference by the number of pulses per revolution of the pulse speed sensor. The theoretical pulse distance is multiplied by the number of pulses from the first beacon to the second beacon to obtain the theoretical pulse distance between the first and second beacons. The tolerance ratio set above the theoretical pulse distance is the maximum pulse distance, and the tolerance ratio set below the theoretical pulse distance is the minimum pulse distance.

[0009] Preferably, the tolerance ratio is in the range of 1%-3%, and the tolerance ratio is calibrated based on the wheel wear threshold, the operating environment temperature range and the track smoothness level, and is dynamically updated through the track line database.

[0010] Preferably, in step 4, after determining that the slipping condition has not been exited, steps 1-4 are re-executed until it is determined that the slipping condition has been exited or the time spent in the slipping condition exceeds a set threshold.

[0011] Preferably, if the time spent in a slipping condition exceeds a set threshold, it is determined that the device is in a slipping state and an alarm signal is issued.

[0012] Preferably, the first and second beacons are existing beacons pre-set on the track line, and a dense beacon group is arranged in the train entry section, with the distance between any two adjacent beacons in the dense beacon group not exceeding 5 meters.

[0013] Preferably, the threshold range is adjusted according to the train's operating status. The threshold range is 10-15 seconds when the train is running normally and 5-8 seconds when braking. The alarm signal is sent to the train's onboard control system and the ground dispatch center.

[0014] The beneficial effects of this invention are: This invention does not rely on additional speed sensors such as radar and accelerometers. It can accurately determine the train exiting the slippage condition by using the collaborative detection logic of existing track beacons and pulse speed sensors. This effectively avoids over-speed measurement faults and subway braking stops caused by slight slippage, and significantly improves the continuity of rail transit operation and system availability.

[0015] By employing an independent verification and full-pass mechanism with at least two pulse speed sensors, a safety redundancy design is formed, avoiding the risk of misjudgment caused by a single sensor failure or common cause failure. This further enhances the safety and reliability of exit slippage judgment, meeting the high safety standards of rail transit signaling systems.

[0016] Prioritize the use of existing beacons in the densely packed track entry sections, and rely on a high-precision track database to ensure the accuracy of beacon positions. This approach not only eliminates the need for large-scale additional equipment, reducing implementation costs, but also adapts to scenarios where train braking slippage is frequent, thus improving the economic efficiency and practical applicability of the solution. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0018] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0019] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0020] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0021] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0022] Example: Methods for determining exit from slippage conditions based on beacon readings, such as... Figure 1 As shown, it includes the following steps: Step 1: Obtain the position information of the first and second beacons set on the track, and calculate the distance between the first and second beacons; Step 2: The pulse velocity sensor acquires the cumulative pulse count at the first beacon and the second beacon, respectively; Step 3: Calculate the minimum pulse distance and maximum pulse distance between the first and second beacons based on the cumulative pulse count at the first and second beacons. Step 4: Determine whether the distance between the first beacon and the second beacon is between the minimum pulse distance and the maximum pulse distance. If it is between the minimum pulse distance and the maximum pulse distance, it is determined that the slippage condition has been exited and the normal working state has been restored; otherwise, it is determined that the slippage condition has not been exited.

[0023] In this embodiment, two pulse speed sensors are used. Each pulse speed sensor independently executes steps 2 to 4. Normal operation resumes only when all pulse speed sensors determine that the slippage condition has been exited. Through the independent verification and full-pass mechanism of at least two pulse speed sensors, a safety redundancy design is formed, avoiding the risk of misjudgment caused by a single sensor failure or common-cause failure. This further enhances the safety and reliability of the slippage exit judgment, meeting the safety functional requirements of the rail transit signaling system.

[0024] Step 3 specifically includes: The difference between the cumulative pulse counts at the first and second beacons is calculated to represent the pulse count from the first beacon to the second beacon. The theoretical pulse distance is obtained by dividing the wheel circumference by the number of pulses per revolution of the pulse speed sensor. Multiplying this theoretical pulse distance by the pulse count from the first to the second beacon gives the theoretical pulse distance between the two beacons. A tolerance percentage above the theoretical pulse distance represents the maximum pulse distance, and a tolerance percentage below the theoretical pulse distance represents the minimum pulse distance. The tolerance percentage ranges from 1% to 3%, and is calibrated based on wheel wear thresholds, operating temperature ranges, and track smoothness levels, and is dynamically updated using a track database. Calculating the minimum / maximum pulse distance based on the theoretical pulse distance combined with the tolerance percentage allows for flexible adaptation to actual operating variables such as wheel wear, temperature changes, and track smoothness differences, reducing the impact of environmental and equipment wear on judgment accuracy and improving the method's environmental adaptability and robustness.

[0025] In step 4, after determining that the slipping condition has not been exited, steps 1-4 are re-executed until it is determined that the slipping condition has been exited or the time spent in the slipping condition exceeds the set threshold.

[0026] If the time spent in a slipping state exceeds the set threshold, it is determined that the system is in a slipping state and an alarm signal is issued.

[0027] The first and second beacons are existing beacons pre-installed on the track. A dense beacon group is deployed within the train's approach section, with the distance between any two adjacent beacons within the group not exceeding 5 meters. This design prioritizes the use of existing dense beacons for train approach, eliminating the need for large-scale additional beacon installations. This approach is suitable for train braking slippage during approach scenarios, reduces project implementation costs, and allows all passing trains to share the beacons, improving resource utilization and the overall economic efficiency of the solution.

[0028] The threshold range is adjusted according to the train's operating status. During normal train operation, the threshold range is 10-15 seconds, and during braking, the threshold range is 5-8 seconds. The alarm signal is sent to the train's onboard control system and the ground dispatch center.

[0029] Specifically, the application scheme of this embodiment is applied to the braking scenario of a metro train entering a station in urban rail transit. The train model is a Type A metro train, and the operating line is Metro Line 3 in a certain city. The entry section has a pre-set dense beacon group, and the distance between adjacent beacons in the beacon group is 3 meters. This section is a high-risk area for wheel slippage. The train is equipped with two pulse speed sensors (OPG1, OPG2), which are installed on the wheels of different wheelsets of the train, and are used to independently perform slippage exit judgment.

[0030] When the train enters the braking stage from normal operation in the section, the wheels slip due to slight dampness on the track surface during the initial braking phase. The on-board signal system detects abnormal speed fluctuations in the outputs of OPG1 and OPG2, determines that the train has entered a slipping condition, and initiates the judgment method described in this embodiment.

[0031] The onboard system retrieves the coordinates of the first beacon B1 (X1=123456.789m, Y1=987654.321m) and the second beacon B2 (X2=123459.789m, Y2=987654.321m) from the track line database, and calculates the actual distance between B1 and B2, D_12=√. The train continues to brake and move. When the onboard beacon reader captures beacon B1, OPG1 records the cumulative pulse count N1-1=85620, and OPG2 records the cumulative pulse count N1-2=87340. When beacon B2 is captured, OPG1 records the cumulative pulse count N2-1=85632, and OPG2 records the cumulative pulse count N2-2=87352.

[0032] Calculate the pulse count difference: Pulse count difference ΔN1 for OPG1 = N2-1 - N1-1 = 85632 - 85620 = 12 pulses; Pulse count difference ΔN2 for OPG2 = N2-2 - N1-2 = 87352 - 87340 = 12 pulses; According to the formula "Theoretical pulse distance = Wheel circumference / OPG pulses per revolution", the theoretical pulse distance L0 = C / N = 2.5 meters / 100 pulses = 0.025 meters / pulse; The theoretical pulse distance L1 for OPG1 = ΔN1 × L0 = 12 × 0.025 = 0.3 meters; The theoretical pulse distance L2 for OPG2 = ΔN2 × L0 = 12 × 0.025 = 0.3 meters; Taking a tolerance ratio of 2%, the maximum pulse distance Lmax1 for OPG1 = L1 × (1 + 2%) = 0.3 × 1.02 = 0.306 The minimum pulse distance Lmin1 = L1 × (1-2%) = 0.3 × 0.98 = 0.294 meters; the maximum pulse distance Lmax2 = L2 × (1+2%) = 0.306 meters, and the minimum pulse distance Lmin2 = L2 × (1-2%) = 0.294 meters.

[0033] Comparing the actual beacon spacing with the pulse distance range: For OPG1, is Lmin1 (0.294 m) ≤ D_12 (3.0 m) ≤ Lmax1 (0.306 m)? No; For OPG2, is Lmin2 (0.294 m) ≤ D_12 (3.0 m) ≤ Lmax2 (0.306 m)? No. Therefore, both OPGs determine that they have not exited the slippage condition and trigger the retry mechanism.

[0034] The vehicle system automatically switches beacon groups, selecting the first beacon B3 (K12+316m) and the second beacon B4 (K12+319m), and re-executes steps 1-4: Step 1: Obtain the actual distance between B3 and B4, D_34 = 3.0 meters; Step 2: When capturing B3, the cumulative number of pulses for OPG1 is N3-1=85645, and the cumulative number of pulses for OPG2 is N3-2=87365; when capturing B4, the cumulative number of pulses for OPG1 is N4-1=85657, and the cumulative number of pulses for OPG2 is N4-2=87377. Step 3: ΔN1 = 12 pulses, ΔN2 = 12 pulses, the theoretical pulse distance is still 0.3 meters, Lmax = 0.306 meters, Lmin = 0.294 meters; Step 4: If D_34 is still not within the pulse distance range, continue to retry.

[0035] After a retry process lasting 5.5 seconds, the beacon group (B5 and B6) was switched for the third time to make a judgment, but the conditions were still not met. At this point, the slippage condition lasted for 6 seconds. The onboard system determined that the train was in a continuous slippage state and immediately issued an alarm signal, which was simultaneously sent to the train's onboard control system and the ground dispatch center. At the same time, the train's graded braking protection was triggered to ensure operational safety.

[0036] In summary, this embodiment achieves the following effects: 1. Relying on the existing dense beacons on the track, it can complete the slippage exit judgment without the need to install additional sensors such as radar and accelerometers, which is suitable for scenarios with limited vehicle installation conditions; 2. The mechanism of independent verification and full pass of two OPGs avoids the risk of single sensor failure and meets the safety redundancy requirements of rail transit; A tolerance range of 3.1%-3% adapts to variables such as wheel wear and temperature changes; a dense beacon spacing of 3 meters improves judgment and response speed; and a braking threshold of 6 seconds balances safety and operational efficiency. 4. Alarm signals are synchronized to the vehicle and ground systems, enabling rapid risk handling and effectively preventing excessive braking and stopping caused by slight slippage, thus improving the continuity of line operation.

[0037] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0038] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for determining exit from slippage conditions based on beacon reading, characterized in that: Includes the following steps: Step 1: Obtain the position information of the first and second beacons set on the track, and calculate the distance between the first and second beacons; Step 2: The pulse velocity sensor acquires the cumulative pulse count at the first beacon and the second beacon, respectively; Step 3: Calculate the minimum pulse distance and maximum pulse distance between the first and second beacons based on the cumulative pulse count at the first and second beacons. Step 4: Determine whether the distance between the first beacon and the second beacon is between the minimum pulse distance and the maximum pulse distance. If it is between the minimum pulse distance and the maximum pulse distance, it is determined that the slippage condition has been exited and the normal working state has been restored; otherwise, it is determined that the slippage condition has not been exited.

2. The method for determining exit from slippage condition based on beacon reading according to claim 1, characterized in that, At least two pulse speed sensors are set up, and each pulse speed sensor independently executes steps 2 to 4. Normal operation is restored only when all pulse speed sensors determine that the slippage condition has been exited.

3. The method for determining exit from slippage condition based on beacon reading according to claim 1, characterized in that, Step 3 specifically includes: The difference between the cumulative pulse counts at the first and second beacons is the pulse count from the first beacon to the second beacon. The theoretical pulse distance is obtained by dividing the wheel circumference by the number of pulses per revolution of the pulse speed sensor. The theoretical pulse distance is multiplied by the number of pulses from the first beacon to the second beacon to obtain the theoretical pulse distance between the first and second beacons. The tolerance ratio set above the theoretical pulse distance is the maximum pulse distance, and the tolerance ratio set below the theoretical pulse distance is the minimum pulse distance.

4. The method for determining exit from slippage condition based on beacon reading according to claim 3, characterized in that, The tolerance ratio ranges from 1% to 3%. The tolerance ratio is calibrated based on the wheel wear threshold, the operating environment temperature range, and the track smoothness level, and is dynamically updated through the track line database.

5. The method for determining exit from slippage condition based on beacon reading according to claim 1, characterized in that, In step 4, after determining that the slipping condition has not been exited, steps 1-4 are re-executed until it is determined that the slipping condition has been exited or the time spent in the slipping condition exceeds the set threshold.

6. The method for determining exit from slippage condition based on beacon reading according to claim 5, characterized in that, If the time spent in a slipping state exceeds the set threshold, it is determined that the system is in a slipping state and an alarm signal is issued.

7. The method for determining exit from slippage condition based on beacon reading according to claim 1, characterized in that, The first and second beacons are existing beacons pre-set on the track line, and a dense beacon group is arranged in the train entry section, with the distance between any two adjacent beacons in the dense beacon group not exceeding 5 meters.

8. The method for determining exit from slippage condition based on beacon reading according to claim 5, characterized in that, The threshold range is adjusted according to the train's operating status. During normal train operation, the threshold range is 10-15 seconds, and during braking, the threshold range is 5-8 seconds. The alarm signal is sent to the train's onboard control system and the ground dispatch center.

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