Train safety speed measuring device and method and positioning system

Abstract

The invention discloses a train safety speed measuring device and method and a positioning system, and the device comprises a plurality of speed measuring instrument combination mechanisms, and each speed measuring instrument combination mechanism comprises at least two laser speed measuring instruments; the support comprises at least two supporting rods, one ends of the at least two supporting rods or extension lines of the ends of the at least two supporting rods have an intersection point, the included angle between any two supporting rods is fixed, and the at least two laser velocimeters and the at least two supporting rods are arranged in a one-to-one correspondence mode; the ejector rod is located at the top of the support, and the ejector rod is connected with a train bogie; and a laser beam of each laser velocimeter corresponds to a rail surface of a train rail. The speed of the train is directly measured, the speed measurement error caused by wheel idling and slipping is avoided, the speed measurement precision is improved, the positioning precision of the train is improved, the safety margin is shortened, and the operation efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of rail transit technology, specifically to a train safety speed measurement device, method, and positioning system based on a laser Doppler velocimeter. Background Technology

[0002] In the field of rail transit, the safe measurement of train speed is fundamental to train control. Traditional train speed measurement methods use wheel-axle systems, where an coded odometer mounted on the axle rotates at the same speed as the wheel. By measuring the angle of rotation of the odometer and knowing the wheel diameter, the distance the vehicle has traveled can be calculated. This distance divided by the travel time yields the train's speed. The problem with this method is that the wheels, running on the rails, can slip and spin during braking and acceleration. In these situations, the wheel's rotation and the distance the train has traveled are not equal, sometimes making accurate speed measurement impossible. This necessitates increasing the safety margin, which in turn increases the estimation margin for the train's position, leading to longer train intervals and reduced railway operating efficiency.

[0003] A laser Doppler velocimeter is a device that uses the Doppler effect of a laser to measure relative speed. Its laser source frequency can be modulated. When the emitted laser shines on the surface of the target, it is reflected back. If the target has a velocity relative to the direction of laser illumination, a Doppler frequency shift will occur. Therefore, the velocimeter can obtain the target's velocity relative to the laser by measuring the frequency shift of the reflected light. However, existing technology for measuring train speed using laser Doppler velocimeters has the following problems: Because the laser velocimeter is installed at the bottom of the train and must illuminate the rails at an angle downwards, the measured speed cannot be directly equal to the train speed; during train operation, the angle fluctuates in real time due to vehicle vibration, so using a preset fixed value for calculation still cannot accurately measure the train speed. Summary of the Invention

[0004] The purpose of this invention is to provide a train safety speed measurement device, method, and positioning system. It aims to solve the problems of existing laser speed measuring instruments being unable to directly measure or calculate train speed, and the difficulty in accurately measuring train speed due to the influence of train vibration.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] On one hand, the present invention provides a train safety speed measuring device, comprising:

[0007] Several speed measuring device assembly mechanisms, each speed measuring device assembly mechanism including:

[0008] At least two laser velocimeters;

[0009] The bracket includes: at least two support rods, one end of the at least two support rods or the extension of one end of the at least two support rods having the same intersection point, the included angle between any two support rods being fixed, and the at least two laser speed measuring instruments being arranged in a one-to-one correspondence with the at least two support rods; and a top rod located at the top of the bracket, the top rod being connected to the train bogie.

[0010] The laser beam of each laser velocimeter corresponds to the rail surface of the train track.

[0011] Preferably, the top rod is arranged parallel to the direction of train operation.

[0012] Preferably, several speed measuring instrument combination mechanisms are arranged one-to-one on several bogies of the train.

[0013] Preferably, each of the speed measuring device assembly mechanisms includes: three laser speed measuring devices and three support rods, and the three support rods are not on the same plane.

[0014] On the other hand, the present invention also provides a train safety speed measurement method, which is implemented using the above-mentioned train safety speed measurement device, the method comprising:

[0015] The velocities measured by the at least two laser velocimeters are obtained respectively;

[0016] The train speed and speed measurement error are calculated based on the speed measured by each of the laser speed measuring instruments and the angle between each pair of support rods.

[0017] Based on the train speed calculated from different speed measuring instrument combinations and the speed measurement error, the measurement result of the train speed and the safe speed of the train are calculated.

[0018] Preferably, if two laser speedometers and two support rods are provided, the calculation of the train speed based on the speed measured by each laser speedometer and the angle between each pair of support rods includes:

[0019] Calculate the speed v of the train according to the following expression:

[0020]

[0021] Among them, v A v B θ represents the speed measured by the two laser velocimeters respectively; θ represents the included angle between the two support rods.

[0022] Preferably, the calculation of the speed measurement error based on the speed measured by each of the laser velocimeters and the angle between each pair of support rods includes:

[0023] The speed measurement error ε is calculated according to the following expression:

[0024]

[0025] Where, Δv A Δv B These are the speed measurement errors of two speed measuring instruments in the same speed measuring instrument assembly mechanism.

[0026] Preferred options also include:

[0027] Determine whether the train speed calculated by different speed measuring instrument combinations is valid;

[0028] If the train speed calculated in different speed measuring instrument combination mechanisms is valid, then the measurement result of the train speed is calculated based on the train speed calculated in different speed measuring instrument combination mechanisms and the speed measurement error.

[0029] If any of the train speeds calculated by different speed measuring device combinations is invalid, then the invalid train speed is discarded.

[0030] Preferably, if two speed measuring instrument combination mechanisms are provided, the determination of whether the train speed calculated in different speed measuring instrument combination mechanisms is valid specifically includes:

[0031] If |Δv|≤ε′, where |Δv|=|v1-v2|; v1 and v2 represent the train speeds calculated by the two speed measuring instrument combinations, respectively; ε′=max(ε1,ε2); ε1 and ε2 represent the speed measurement errors calculated by the two speed measuring instrument combinations, then the train speeds v1 and v2 calculated by the two speed measuring instrument combinations pass the comparison, and the train speeds v1 and v2 calculated by the two speed measuring instrument combinations are valid.

[0032] If |Δv|>ε′, then the comparison of train speeds v1 and v2 calculated by the two speed measuring instrument combinations in the current speed measuring cycle fails.

[0033] Preferably, if two speed measuring instrument combination mechanisms are provided, the measurement result of calculating the train speed based on the train speed calculated in different speed measuring instrument combination mechanisms and the speed measurement error includes:

[0034] If the train speed calculated by both speed measuring device combinations is valid, the measurement result v′ of the train speed is calculated according to the following expression:

[0035]

[0036] Wherein, v1 and v2 represent the train speeds calculated by the two speed measuring instrument combination mechanisms, respectively.

[0037] Preferably, if two speed measuring instrument combination mechanisms are provided, the calculation of the train's safe speed based on the train's speed calculated in different speed measuring instrument combination mechanisms and the speed measurement error includes:

[0038] If the train speed calculated by the two speed measuring device combinations passes the comparison, the safe speed V of the train is calculated according to the following expression. safety :

[0039] V safety =[min(v1-ε′, v2-ε′), max(v1+ε′, v2+ε′)]

[0040] Where v1 and v2 represent the train speeds calculated by the two speed measuring instrument combination mechanisms, ε′=max(ε1,ε2); ε1 and ε2 represent the speed measuring errors calculated by the two speed measuring instrument combination mechanisms.

[0041] If the speed comparison between the two speed measuring instruments in the current speed measuring cycle fails, the safe speed for the current speed measuring cycle is calculated based on the safe speed obtained in the previous speed measuring cycle.

[0042] On the other hand, the present invention also provides a train safety speed measurement and positioning system, the system comprising:

[0043] The aforementioned train safety speed measurement device;

[0044] The main processing module is connected to several of the speed measuring instrument combination mechanisms, and is used to receive speed information sent by the several speed measuring instrument combination mechanisms and calculate the speed of the train.

[0045] The train antenna acquires the corresponding beacon information as the train passes the center point of each beacon.

[0046] A beacon reading module is connected to the main processing module and the antenna respectively, receives the beacon information, and sends the beacon information and the corresponding timestamp to the main processing module.

[0047] The main processing module calculates the real-time position of the train based on the beacon information, the corresponding timestamp, and the calculated train speed. After passing a new beacon, the main processing module corrects the real-time position of the train based on the new beacon information and the corresponding timestamp.

[0048] Preferably, both the main processing module and the beacon reading module are 2-out-of-2 architectures.

[0049] Preferably, the main processing module includes a first processing unit and a second processing unit, wherein the first processing unit sends clock synchronization signals to a plurality of speed measuring instrument combination mechanisms, the second processing unit and the beacon reading module respectively.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1. The present invention provides a train safety speed measurement device, method, and positioning system. Compared with the wheel-axle type speed sensor in the prior art, this solution directly measures the speed of the vehicle itself, avoiding speed measurement errors caused by wheel slippage and improving speed measurement accuracy. This, in turn, improves the positioning accuracy of the train, shortens the safety margin, and enhances operational efficiency.

[0052] 2. This invention employs at least two laser speed measuring instruments with fixed relative positions to simultaneously measure speed. The mounting bracket beam is connected to the train bogie and its direction is parallel to the train's running direction, ensuring that the plane formed by the two speed measuring instruments is parallel to the speed direction. The vehicle's speed can be determined through the fixed angular relationship between the two speed measuring instruments, and this speed is unaffected by changes in the elevation angle caused by train vibrations during operation.

[0053] 3. The present invention can use three laser speed measuring instruments with fixed relative positions to measure speed simultaneously. Their mounting plane is connected to the train bogie. The speed of the vehicle can be obtained through the relatively fixed angular relationship between the three speed measuring instruments. This speed is not affected by the changes in the heading angle, pitch angle and roll angle of the vehicle during operation.

[0054] 4. The present invention can use two speed measuring instruments to form a speed measuring instrument combination mechanism. The two independent speed measuring instrument combination mechanisms obtain the train speed value respectively, compare it in pairs, and then fuse it to obtain the safe speed, which is used for train speed measurement, positioning and interval control.

[0055] 5. The speed of the multiple speed measuring device combination mechanism of the present invention can also be obtained by taking m as n, so that when some speed measuring device combination mechanisms cannot work properly due to environmental factors or their own failures, the whole system can still maintain its existing working state and operate normally.

[0056] 6. This invention combines speed measurement and beacon reading functions through a globally synchronized time. By using the beacon position and the timestamp of passing the beacon at intervals, the accumulated mileage is corrected, thereby obtaining a system that can perform continuous high-precision positioning along the entire route. Attached Figure Description

[0057] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings described below are one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0058] Figure 1 This is a schematic diagram of the structure of a train safety speed measuring device provided in an embodiment of the present invention;

[0059] Figure 2 This is a schematic diagram of a train safety speed measuring device provided in an embodiment of the present invention when one end of the two support rods intersects.

[0060] Figure 3 A schematic diagram of a train safety speed measuring device structure provided in an embodiment of the present invention, showing that the extension lines of one end of the two support rods intersect.

[0061] Figure 4 This is a schematic diagram showing the velocity directions of two speed measuring instruments and the angle k between speed measuring instrument B and the train's direction of travel, provided in an embodiment of the present invention.

[0062] Figure 5 This is an installation diagram showing the speeds measured by two laser velocimeters, one positive and one negative, according to an embodiment of the present invention.

[0063] Figure 6 This is a schematic diagram showing the positive and negative velocity directions measured by two laser velocimeters according to an embodiment of the present invention.

[0064] Figure 7 This is an installation diagram of the three support rods and the laser velocimeter provided according to an embodiment of the present invention;

[0065] Figure 8 This is a schematic diagram of a train safety speed measurement and positioning system provided in an embodiment of the present invention.

[0066] Explanation of reference numerals in the attached diagram: 100-bracket; 101-top rod; 102-support rod; 200-laser velocimeter. Detailed Implementation

[0067] The following is in conjunction with the appendix Figures 1 to 8 The train safety speed measuring device, method, and positioning system proposed in this invention will be further described in detail below with specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clarify the illustration of the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable.

[0068] Given that existing laser speed measuring instruments cannot directly measure or calculate train speed, and that train speed is difficult to measure accurately due to the influence of train vibration, the technology has limitations.

[0069] On the one hand, refer to Figure 1 As shown, this embodiment provides a train safety speed measuring device, including: a plurality of speed measuring instrument combination mechanisms, each speed measuring instrument combination mechanism including: at least two laser speed measuring instruments 200, preferably, the laser speed measuring instruments 200 are laser Doppler speed measuring instruments; a bracket 100, which includes: at least two support rods 102, one end of the at least two support rods 102 or the extension line of one end of the at least two support rods 102 having the same intersection point, the included angle between any two support rods 102 being fixed, the at least two laser speed measuring instruments 200 being arranged one-to-one with the at least two support rods 102; a top rod 101, which is located at the top of the bracket 100, and the top rod 101 is connected to the train bogie; the laser beam of each laser speed measuring instrument 200 corresponds to the rail surface of the train rail, so that the laser emitted by the speed measuring instrument can directly hit the rail surface. The top rod 101 is arranged parallel to the train running direction. The plurality of speed measuring instrument combination mechanisms are arranged one-to-one on a plurality of bogies of the train.

[0070] On the other hand, this embodiment also provides a train safety speed measurement method, which is implemented using the above-mentioned train safety speed measurement device. The method includes: acquiring the speeds measured by the at least two laser speed measuring instruments 200 respectively; calculating the train speed and the speed measurement error based on the speed measured by each laser speed measuring instrument 200 and the included angle between each pair of support rods 102; and calculating the measurement result of the train speed and the safe speed of the train based on the train speed calculated in different speed measuring instrument combination mechanisms and the speed measurement error.

[0071] On the other hand, reference Figure 8 As shown, this embodiment also provides a train safety speed measurement and positioning system, the system comprising: the aforementioned train safety speed measurement device; a main processing module, which is connected to a plurality of speed measuring instrument combination mechanisms, for receiving speed information sent by the plurality of speed measuring instrument combination mechanisms and calculating the train speed; a train antenna, for acquiring corresponding beacon information when the train passes the center point of each beacon; a beacon reading module, which is connected to the main processing module and the antenna, for receiving the beacon information and sending the beacon information and the corresponding timestamp to the main processing module; wherein, the main processing module calculates the real-time position of the train based on the beacon information, the corresponding timestamp, and the calculated train speed; after passing a new beacon, the main processing module corrects the real-time position of the train based on the information of the new beacon and the corresponding timestamp.

[0072] Specifically, both the main processing module and the beacon reading module are 2-out-of-2 architectures.

[0073] Specifically, the main processing module includes a first processing unit and a second processing unit. The first processing unit sends clock synchronization signals to a plurality of speed measuring instrument combination mechanisms, the second processing unit and the beacon reading module, respectively.

[0074] The clock source for the entire process is provided by the first processing unit of the main processing module, which simultaneously synchronizes the clock signals to the n speedometer assemblies and the two reading units of the beacon reading module. Thus, when the speedometer assemblies send speed information to the main processing module, they include the corresponding time information (i.e., a timestamp). Similarly, the beacon reading unit determines and obtains the timestamp of the instant the antenna passes through the beacon's center point (i.e., when the wireless signal is strongest), and sends it to the main processing unit.

[0075] Initially, before passing over any beacon, the train cannot determine its position. Moving slowly, after passing the first beacon and obtaining its initial location and corresponding timestamp, the main processing unit can use these coordinates and time as a starting point to continuously calculate the train's real-time position by accumulating the measured high-precision speed. When the train's antenna reads the next beacon and its corresponding timestamp after traveling a certain distance, the main processing unit can update the train's current position using this information, eliminating previously accumulated positioning errors, and restarting the accumulation process from the new beacon coordinates and timestamp.

[0076] The following two embodiments provide a detailed description of the train safety speed measurement device and method:

[0077] Example 1

[0078] In this embodiment, the train safety speed measurement device includes: two speed measuring instrument combination mechanisms, each speed measuring instrument combination mechanism including: two laser speed measuring instruments 200 (reference). Figure 2 (A and B are marked); Support 100, which includes: two support rods 102, one end of the two support rods 102 or the extension of one end of the two support rods 102 having an intersection point, the included angle between the two support rods 102 being fixed, and the two laser speed measuring instruments 200 being arranged one-to-one with the two support rods 102; a top rod 101, which is located at the top of the support 100, and the top rod 101 being connected to the train bogie; the laser beam of each laser speed measuring instrument 200 is aligned with the rail surface of the train track.

[0079] refer to Figure 2 As shown, the two support rods 102 can be configured such that one end of each support rod 102 intersects. Or refer to... Figure 3As shown, the two support rods 102 can also be configured such that the extensions of one end of the two support rods 102 intersect.

[0080] The train safety speed measurement method includes: acquiring the speeds measured by the two laser speed measuring instruments 200 respectively; calculating the train speed and speed measurement error based on the speed measured by each laser speed measuring instrument 200 and the included angle between each pair of support rods 102; and calculating the train speed measurement result and the train safety speed based on the train speed calculated in different speed measuring instrument combination mechanisms and the speed measurement error.

[0081] The calculation of the train speed based on the speed measured by each of the laser velocimeters and the angle between each pair of support rods includes:

[0082] Assuming the train's speed is v, speedometers A and B measure the speed v. A v B Let k be the angle between speedometer B and the direction of train travel, and θ be the angle between speedometers A and B. When the train is running, angle k will change due to vibration. (Refer to...) Figure 4 As shown, the following system of equations is obtained:

[0083]

[0084] Solving the system of equations in (1), we can obtain the expression for the train's speed v as follows:

[0085]

[0086] As can be seen from equation (2), the calculated train speed v is independent of the angle k. Therefore, the train safety speed measuring device and method designed in this embodiment can eliminate the influence of vibration on vehicle speed measurement.

[0087] Laser speedometers can measure speeds that are either positive or negative, representing speeds in the forward or reverse direction. Therefore, two speedometers can be installed with one facing the direction of the vehicle's movement and the other against it. (Reference) Figure 5 As shown. Similarly, assuming the train's speed is v, speedometers A and B measure the speed v0 respectively. A v B Let k be the angle between speedometer B and the direction of train travel, and θ be the angle between speedometers A and B. When the train is running, angle k will change due to vibration. (Refer to...) Figure 6 As shown. The following system of equations is obtained:

[0088]

[0089] Solving the system of equations in (3), we can obtain the expression for the speed v of the train as follows:

[0090]

[0091] Equation (4) is the same as Equation (1). Therefore, regardless of whether the speed measured by the two laser speedometers is the forward or reverse speed, the speed v of the train can be expressed by Equation (1).

[0092] The calculation of the speed measurement error based on the speed measured by each laser velocimeter and the angle between each pair of support rods includes:

[0093] The speed measurement error ε is calculated according to the following expression:

[0094]

[0095] Where, Δv A Δv B These are the speed measurement errors of two speed measuring instruments in the same speed measuring instrument assembly mechanism.

[0096] Expanding equation (5) using Taylor series, equation (5) can be simplified to:

[0097]

[0098] The threshold ε is based on the speed v measured by two speedometers A and B respectively. A v B get.

[0099] From a functional safety perspective, two independent speed measurement sources are needed to provide two values ​​for comparison, forming a 2-out-of-2 combined fail-safe architecture. Therefore, by installing two independent speed measuring devices on different bogies of the vehicle, two speed measurement sources are acquired for 2-out-of-2 comparison. The comparison principle is as follows:

[0100] Determine whether the train speed calculated by different speed measuring instrument combinations is valid.

[0101] If the train speeds calculated by different speed measuring device combinations are all valid, then the train speed measurement result is calculated based on the train speeds calculated by the different speed measuring device combinations and the speed measurement error. If any of the train speeds calculated by different speed measuring device combinations is invalid, then the invalid train speed is discarded.

[0102] If |Δv|≤ε′, where |Δv|=|v1-v2|; v1 and v2 represent the train speeds calculated by the two speed measuring instrument combinations, respectively; ε′=max(ε1,ε2); ε1 and ε2 represent the speed measurement errors calculated by the two speed measuring instrument combinations, then the train speeds v1 and v2 calculated by the two speed measuring instrument combinations pass the comparison, and the train speeds v1 and v2 calculated by the two speed measuring instrument combinations are valid.

[0103] If |Δv|>ε′, then the comparison of train speeds v1 and v2 calculated by the two speed measuring instrument combinations in the current speed measuring cycle fails.

[0104] If the train speed calculated by both speed measuring instrument combinations is valid, the calculation of the train speed measurement result based on the train speed calculated by different speed measuring instrument combinations and the speed measurement error includes: calculating the train speed measurement result v′ according to the following expression:

[0105]

[0106] Wherein, v1 and v2 represent the train speeds calculated by the two speed measuring instrument combination mechanisms, respectively.

[0107] From a functional safety perspective, it is also necessary to obtain a speed range that includes a margin, meaning the actual speed must fall within this range, and the safe speed range of the actual speed is the safe speed. The calculation of the train's safe speed based on the train speed calculated from different speed measuring instrument combinations and the speed measurement error includes: if the train speeds calculated from two speed measuring instrument combinations pass the comparison, the train's safe speed V is calculated according to the following expression. safety :

[0108]

[0109] Where v1 and v2 represent the train speeds calculated by the two speed measuring instrument combination mechanisms, respectively, ε′=max(ε1,ε2); ε1 and ε2 represent the speed measurement errors calculated by the two speed measuring instrument combination mechanisms, respectively.

[0110] If the speed comparison between the two speed measuring instruments in the current speed measuring cycle fails, the safe speed for the current speed measuring cycle is calculated based on the safe speed obtained in the previous speed measuring cycle.

[0111] Because there are only two speed measuring devices combined, a failed comparison means there is no suitable safe speed value for the current speed measurement cycle. Therefore, it is necessary to use the safe speed V obtained from the previous speed measurement cycle. safety1 The range is expressed by the following formula:

[0112] Vsafety1 =[min(v1-ε′, v2-ε′), max(v1+ε′, v2+ε′)] (9)

[0113] Considering the acceleration during the current speed measurement cycle, the potential speed changes introduced can be used to determine the safe speed V for the current speed measurement cycle. safety2 for:

[0114] V safety2 =[min(v1-ε′, v2-ε′)-a1t, max(v1+ε′, v2+ε′)+a2t] (10)

[0115] Where a1 represents the train's maximum deceleration, a2 represents the train's maximum acceleration, and t represents the time of the current speed measurement cycle.

[0116] The safe speed is determined by taking into account measurement errors, calculating the range of train positions, and then calculating vehicle intervals for relevant protection.

[0117] Example 2

[0118] refer to Figure 7 As shown, the train safety speed measurement device includes: two speed measuring instrument combination mechanisms, each speed measuring instrument combination mechanism including: three laser speed measuring instruments 200 (respectively...) Figure 7 The three supports (A, B, and C) are marked on the chart. The support 100 includes: three support rods 102, one end of each support rod 102 or its extension intersecting at a point; the included angle between the three support rods 102 is fixed; and three laser speedometers 200 are correspondingly arranged with the three support rods 102. A top rod 101 is located at the top of the support 100 and is connected to the train bogie. The laser beam of each laser speedometer corresponds to the rail surface of the train track. The three support rods are not on the same plane.

[0119] refer to Figure 2 As shown, the two support rods 102 can be configured such that one end of each support rod 102 intersects. Or refer to... Figure 3 As shown, the two support rods 102 can also be configured such that the extensions of one end of the two support rods intersect.

[0120] The train safety speed measurement method includes: acquiring the speeds measured by the three laser speed measuring instruments 200 respectively; calculating the train speed and speed measurement error based on the speed measured by each laser speed measuring instrument 200 and the included angle between each pair of support rods 102; and calculating the train speed measurement result and the train safety speed based on the train speed calculated in different speed measuring instrument combination mechanisms and the speed measurement error.

[0121] After the three laser velocimeters A, B, and C are installed, the included angles between any two of the three support rods are α, β, and γ, respectively. The velocimeters A, B, and C measure the velocimeters v. A v B v C The train's speed v can then be derived using the six variables mentioned above:

[0122]

[0123] Three laser velocimeters can also be combined into a speed measuring combination mechanism. The speed measuring error ε measured by each speed measuring combination mechanism is:

[0124]

[0125] Where, Δv A Δv B Δv C The speed measurement errors of three laser velocimeters, A, B, and C, are respectively.

[0126]

[0127] Therefore, when using two combined speed measuring units (each consisting of three laser speed measuring units), v1 and v2, and ε1 and ε2 will be obtained. From a functional safety perspective, two independent speed measuring sources are needed to provide two values ​​for comparison, forming a 2-out-of-2 combined fail-safe architecture. Therefore, by installing two independent speed measuring unit combinations on different bogies of the vehicle, two speed measuring sources are obtained for 2-out-of-2 comparison. The comparison principle is as follows:

[0128] Determine whether the train speed calculated by different speed measuring instrument combinations is valid.

[0129] If the train speeds calculated by different speed measuring device combinations are all valid, then the train speed measurement result is calculated based on the train speeds calculated by the different speed measuring device combinations and the speed measurement error. If any of the train speeds calculated by different speed measuring device combinations is invalid, then the invalid train speed is discarded.

[0130] If |Δv|≤ε′, where |Δv|=|v1-v2|; v1 and v2 represent the train speeds calculated by the two speed measuring instrument combinations, respectively; ε′=max(ε1,ε2); ε1 and ε2 represent the speed measurement errors calculated by the two speed measuring instrument combinations, then the train speeds v1 and v2 calculated by the two speed measuring instrument combinations pass the comparison, and the train speeds v1 and v2 calculated by the two speed measuring instrument combinations are valid.

[0131] If |Δv|>ε′, then the comparison of train speeds v1 and v2 calculated by the two speed measuring instrument combinations in the current speed measuring cycle fails.

[0132] If the train speed calculated by both speed measuring instrument combinations is valid, the calculation of the train speed measurement result based on the train speed calculated by different speed measuring instrument combinations and the speed measurement error includes: calculating the train speed measurement result v′ according to the following expression:

[0133]

[0134] Wherein, v1 and v2 represent the train speeds calculated by the two speed measuring instrument combination mechanisms, respectively.

[0135] From a functional safety perspective, it is also necessary to obtain a speed range that includes a margin, meaning the actual speed must fall within this range, and the safe speed range of the actual speed is the safe speed. The calculation of the train's safe speed based on the train speed calculated from different speed measuring instrument combinations and the speed measurement error includes: if the train speeds calculated from two speed measuring instrument combinations pass the comparison, the train's safe speed V is calculated according to the following expression. safety :

[0136]

[0137] Where v1 and v2 represent the train speeds calculated by the two speed measuring instrument combination mechanisms, respectively, ε′=max(ε1,ε2); ε1 and ε2 represent the speed measurement errors calculated by the two speed measuring instrument combination mechanisms, respectively.

[0138] If the speed comparison between the two speed measuring instruments in the current speed measuring cycle fails, the safe speed for the current speed measuring cycle is calculated based on the safe speed obtained in the previous speed measuring cycle.

[0139] Because there are only two speed measuring devices combined, a failed comparison means there is no suitable safe speed value for the current speed measurement cycle. Therefore, it is necessary to use the safe speed V obtained from the previous speed measurement cycle. safety1 The range is expressed by the following formula:

[0140] V safety1 =[min(v1-ε′, v2-ε′), max(v1+ε′, v2+ε′)] (15)

[0141] Considering the acceleration during the current speed measurement cycle, the potential speed changes introduced can be used to determine the safe speed V for the current speed measurement cycle. safety2 for:

[0142] V safety2=[min(v1-ε′, v2-ε′)-a1t, max(v1+ε′, v2+ε′)+αa2t] (16)

[0143] Where a1 represents the train's maximum deceleration, a2 represents the train's maximum acceleration, and t represents the time of the current speed measurement cycle.

[0144] The safe speed is determined by taking into account measurement errors, calculating the range of train positions, and then calculating vehicle intervals for relevant protection.

[0145] The two speed measuring device combinations mentioned in Embodiments 1 and 2 may be affected by interference during use. For example, due to water accumulation on the track surface, the laser beam emitted by one of the speed measuring device combinations may be reflected elsewhere by the water, resulting in a very weak echo received by the laser speed measuring device, affecting speed measurement. In subsequent processing, the comparison between the speed measuring device combinations may fail and be redirected to the safety side, affecting system availability.

[0146] Therefore, to reduce the occurrence of speed comparison discrepancies, the system's applicability is improved by increasing the number of speed measuring device assemblies. In some embodiments, the number of speed measuring device assemblies is increased. For example, one speed measuring device assembly is installed under the bogie of each train car, resulting in a total of n speed measuring device assemblies, thereby obtaining n speed measurement results v1, v2...v n The process involves averaging the n speed values, discarding the m speed values ​​with the largest variance, and then averaging the remaining nm values ​​to obtain the final speed measurement result. The safe speed is set to V. safety = [(minimum value among nm velocity values ​​- ε″), (maximum value among nm velocity values ​​+ ε″)], where ε″ equals the maximum error value corresponding to the nm velocity values. n and m can be configured according to the project installation and debugging situation.

[0147] Using the high-precision speed measurement scheme described above, the distance the train has traveled can be accumulated by multiplying the speed and the time interval, thereby obtaining the train's position information.

[0148] In summary, this embodiment presents a train safety speed measurement device, method, and positioning system. Compared to existing wheel-axle speed sensors, this solution directly measures the vehicle's speed, avoiding speed measurement errors caused by wheel slippage, improving speed measurement accuracy, and consequently improving train positioning accuracy, shortening the safety margin, and increasing operational efficiency. Furthermore, this embodiment employs at least two laser speedometers fixed in relative positions for simultaneous speed measurement. The mounting bracket beam is connected to the train bogie, and its direction is parallel to the train's running direction, ensuring that the plane formed by the two speedometers is parallel to the speed direction. The vehicle speed can be determined by the relatively fixed angular relationship between two speed measuring instruments, and this speed is not affected by the change in pitch angle caused by train vibration during operation. In this embodiment, three speed measuring instruments with fixed relative positions can be used to measure the speed simultaneously. Their mounting plane is connected to the train bogie. The vehicle speed can be determined by the relatively fixed angular relationship between the three speed measuring instruments, and this speed is not affected by the changes in heading angle, pitch angle, and roll angle during vehicle operation. In this embodiment, two speed measuring instruments can also be combined into a speed measuring instrument combination mechanism. The speed values ​​obtained by the two independent speed measuring instrument combination mechanisms are compared in pairs and then fused to obtain a safe speed for train speed measurement, positioning, and interval control. In this embodiment, multiple speed measuring instrument combination mechanisms can also obtain the speed by taking n out of m, so that the entire system can still maintain its existing working state and operate normally when some speed measuring instrument combination mechanisms cannot work normally due to environmental factors or their own failures. By combining the speed measurement and beacon reading functions through a globally synchronized time, the accumulated mileage is corrected by the position of the beacon and the timestamp of passing the beacon at intervals, thereby obtaining a system that can perform continuous high-precision positioning along the entire line.

[0149] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0150] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0151] In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0152] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A train safety speed measuring device, characterized in that, include: Several speed measuring device assembly mechanisms, each of which includes: At least two laser velocimeters; The bracket includes: at least two support rods, one end of the at least two support rods or the extension of one end of the at least two support rods having the same intersection point, the included angle between any two of the support rods being fixed, and at least two laser speed measuring instruments being arranged one-to-one with the at least two support rods; and a top rod located at the top of the bracket, the top rod being connected to the train bogie. The laser beam of each laser velocimeter corresponds to the rail surface of the train track.

2. The train safety speed measuring device as described in claim 1, characterized in that, The top rod is set parallel to the direction of train travel.

3. The train safety speed measuring device as described in claim 1, characterized in that, Several speed measuring instrument combination mechanisms are installed one-to-one on several bogies of the train.

4. The train safety speed measuring device as described in claim 1, characterized in that, Each of the aforementioned speed measuring device assembly mechanisms includes: three laser speed measuring devices and three support rods, and the three support rods are not on the same plane.

5. A method for safe speed measurement of trains, characterized in that, It is implemented using the train safety speed measuring device as described in any one of claims 1-4, and the method includes: The velocities measured by the at least two laser velocimeters are obtained respectively; The train speed and speed measurement error are calculated based on the speed measured by each of the laser speed measuring instruments and the angle between each pair of support rods. Based on the train speed calculated from different speed measuring instrument combinations and the speed measurement error, the measurement result of the train speed and the safe speed of the train are calculated.

6. The train safety speed measurement method as described in claim 5, characterized in that, If two laser speedometers and two support rods are provided, the calculation of the train speed based on the speed measured by each laser speedometer and the angle between each pair of support rods includes: Calculate the speed v of the train according to the following expression: Among them, v A v B θ represents the speed measured by the two laser velocimeters respectively; θ represents the included angle between the two support rods.

7. The train safety speed measurement method as described in claim 6, characterized in that, The calculation of the speed measurement error based on the speed measured by each of the laser velocimeters and the angle between each pair of support rods includes: The speed measurement error ε is calculated according to the following expression: Where, Δv A Δv B These are the speed measurement errors of two speed measuring instruments in the same speed measuring instrument assembly mechanism.

8. The train safety speed measurement method as described in claim 5, characterized in that, Also includes: Determine whether the train speed calculated by different speed measuring instrument combinations is valid; If the train speed calculated in different speed measuring instrument combination mechanisms is valid, then the measurement result of the train speed is calculated based on the train speed calculated in different speed measuring instrument combination mechanisms and the speed measurement error. If any of the train speeds calculated by different speed measuring device combinations is invalid, then the invalid train speed is discarded.

9. The train safety speed measurement method as described in claim 8, characterized in that, If the speed measuring instrument combination mechanism is provided with two parts, the determination of whether the train speed calculated in different speed measuring instrument combination mechanisms is valid specifically includes: If |Δv|≤ε′, where |Δv|=|v1-v2|; v1 and v2 represent the train speeds calculated by the two speed measuring instrument combinations, respectively; ε′=max(ε1,ε2); ε1 and ε2 represent the speed measurement errors calculated by the two speed measuring instrument combinations, then the train speeds v1 and v2 calculated by the two speed measuring instrument combinations pass the comparison, and the train speeds v1 and v2 calculated by the two speed measuring instrument combinations are valid. If |Δv|>ε′, then the comparison of train speeds v1 and v2 calculated by the two speed measuring instrument combinations in the current speed measuring cycle fails.

10. The train safety speed measurement method as described in claim 5, characterized in that, If the speed measuring instrument combination mechanism is provided with two parts, the measurement result of calculating the train speed based on the train speed calculated in different speed measuring instrument combination mechanisms and the speed measurement error includes: If the train speed calculated by both speed measuring device combinations is valid, the measurement result v′ of the train speed is calculated according to the following expression: Wherein, v1 and v2 represent the train speeds calculated by the two speed measuring instrument combination mechanisms, respectively.

11. The train safety speed measurement method as described in claim 9, characterized in that, If the speed measuring instrument combination mechanism is provided with two parts, the calculation of the train's safe speed based on the train speed calculated in different speed measuring instrument combination mechanisms and the speed measuring error includes: If the train speed calculated by the two speed measuring device combinations passes the comparison, the safe speed V of the train is calculated according to the following expression. safety : V safety =[min(v1-ε′, v2-ε′), max(v1+ε′, v2+ε′)] Where v1 and v2 represent the train speeds calculated by the two speed measuring instrument combination mechanisms, ε′=max(ε1,ε2); ε1 and ε2 represent the speed measuring errors calculated by the two speed measuring instrument combination mechanisms. If the speed comparison between the two speed measuring instruments in the current speed measuring cycle fails, the safe speed for the current speed measuring cycle is calculated based on the safe speed obtained in the previous speed measuring cycle.

12. A train safety speed measurement and positioning system, characterized in that, The system includes: The train safety speed measuring device as described in any one of claims 1-4; The main processing module is connected to several of the speed measuring instrument combination mechanisms, and is used to receive speed information sent by the several speed measuring instrument combination mechanisms and calculate the speed of the train. The train antenna acquires the corresponding beacon information as the train passes the center point of each beacon. A beacon reading module is connected to the main processing module and the antenna respectively, receives the beacon information, and sends the beacon information and the corresponding timestamp to the main processing module. The main processing module calculates the real-time position of the train based on the beacon information, the corresponding timestamp, and the calculated train speed. After passing a new beacon, the main processing module corrects the real-time position of the train based on the new beacon information and the corresponding timestamp.

13. The train safety speed measurement and positioning system as described in claim 12, characterized in that, Both the main processing module and the beacon reading module are 2-out-of-2 architectures.

14. The train safety speed measurement and positioning system as described in claim 13, characterized in that, The main processing module includes a first processing unit and a second processing unit. The first processing unit sends clock synchronization signals to a plurality of speed measuring instrument combination mechanisms, the second processing unit and the beacon reading module, respectively.

Images