A method for generating rail profile measurement curve

Abstract

The present invention belongs to the field of track measurement and detection technology, and discloses a method for generating a rail profile measurement curve. The method establishes a two-dimensional coordinate system with the highest point of the top of a standard rail as the coordinate origin, collects the first trajectory data of the rail profile measurement and records it in the two-dimensional coordinate system; obtains the second trajectory data of the contact edge between the measuring wheel and the rail to be measured according to the diameter of the measuring wheel; draws an envelope curve according to the second trajectory data; takes a certain point as the center O in the enclosed area of ​​the envelope curve, takes a certain length as the scanning radius L, and calculates the distance L' between the data point on the envelope curve and the center O. On the same scanning radius L, the data point with the smallest distance L' is taken as the valid data point, and the valid data points are connected in sequence to obtain the rail profile curve. The present invention finally generates the required rail profile curve by searching the inner envelope method, realizes the rapid generation and calculation of the rail profile measurement curve, and the curve generation has high accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of track measurement and detection, and in particular to a method for generating a rail profile measurement curve. Background Art

[0002] In rail transportation, rails and wheels are two parts in direct contact. Accurate wheel and rail geometry is the most effective way to improve efficiency and economy. Scientific profile design can effectively reduce friction and increase the service life of rails and wheels. When rails and wheels are worn, the profiles of wheels and rails change, which intensifies wear and vibration. At this time, accurate measurement equipment is the key to guiding rail grinding technology. Under the guidance of accurate measurement data, restoring rails and wheels to their original design profiles is a key technical task in track maintenance.

[0003] In actual operation, the operator manipulates the measuring instrument to make the measuring wheel roll along the cross section of the rail head. During the entire process of the measuring wheel moving, all its tracks will be recorded. In the actual process of collecting track data, due to human factors (such as hand shaking, repeated measurement of the profile of a certain area, etc.), or the need to switch the left and right measuring wheels, although the final measuring wheel track will cover the entire cross section of the rail head, it is inevitable that there will be a lot of additional track data, which will affect the final profile data calculation. Summary of the invention

[0004] The object of the present invention is to provide a method for generating a rail profile measurement curve, so as to quickly generate and calculate trajectory data obtained by measuring the rail profile to obtain the rail profile measurement curve.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for generating a rail profile measurement curve, comprising the following steps:

[0007] S1, establishing a two-dimensional coordinate system with the highest point of the standard rail top as the coordinate origin, collecting first trajectory data of rail profile measurement and recording discrete data points of the first trajectory data in the two-dimensional coordinate system;

[0008] S2, obtaining second trajectory data of the contact edge between the measuring wheel and the rail to be measured according to the diameter of the measuring wheel and the first trajectory data;

[0009] S3, drawing an envelope curve according to the second trajectory data;

[0010] S4, taking a certain point as the center O in the enclosed area of ​​the envelope curve, taking a certain length as the scanning radius L, and calculating the distance L' between the data point on the envelope curve and the center O. On the same scanning radius L, the data point with the smallest distance L' is taken as the valid data point, and the valid data points are connected in sequence to obtain the rail profile curve.

[0011] Optionally, the two-dimensional coordinate system in step S1 is an XZ two-dimensional coordinate system in an XYZ three-axis coordinate system, the Y axis is along the long axis direction of the standard rail, and the XY two-dimensional coordinate system is a horizontal coordinate system.

[0012] Optionally, the trajectory data in step S1 is obtained by measuring by rotating the measuring wheel at least twice left and right.

[0013] Optionally, before step S4, a data preprocessing step is further included: performing data preprocessing on the first trajectory data and / or the second trajectory data to obtain third trajectory data, drawing the envelope curve according to the third trajectory data, and then executing step S4.

[0014] Optionally, the data preprocessing in step S4 is low-pass filtering denoising processing and / or moving average denoising processing.

[0015] Optionally, in step S4, the scanning radius L is greater than the maximum value of the distance L'.

[0016] Optionally, the first trajectory data in step S1 is obtained by a rail head profile measuring instrument, and the rail head profile measuring instrument includes:

[0017] Encoders, wherein two encoders are provided and the two encoders are connected by a connecting rod;

[0018] A measuring arm, one end of which is connected to one of the encoders, and the other end of which is rotatably connected to a measuring wheel;

[0019] A host computer is connected to the two encoders for communication. The two encoders collect the rotation angles of the connecting rod and the measuring arm and upload the data to the host computer.

[0020] Optionally, the first trajectory data is:

[0021] X(M)=(L1-L2 cosω)sinθ1-L2 sinωcosθ1

[0022] Y(M)=-(L1-L2 cosω)cosθ1-L2 sinωsinθ1

[0023] Wherein, L1 and L2 are the lengths of the connecting rod and the measuring arm respectively, ω is the angle between the measuring arm and the connecting rod, θ1 is the rotation angle of the connecting rod relative to the vertical direction, and θ2 is the rotation angle of the measuring arm relative to the vertical direction.

[0024] Optionally, two measuring wheels are provided, and the two measuring wheels are symmetrically arranged in a herringbone shape on both sides of the long axis direction of the measuring support arm.

[0025] Optionally, each measuring wheel is provided with a magnetic member, and the magnetic member can be adsorbed on the rail to be measured.

[0026] Beneficial effects of the present invention:

[0027] A method for generating a rail profile measurement curve of the present invention records the collected first trajectory data in a two-dimensional coordinate system and draws a curve, and finally generates the required rail profile curve by searching the inner envelope method, thereby realizing rapid generation and calculation of the rail profile measurement curve, and the curve generation has high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of a method for generating a rail profile measurement curve of the present invention;

[0029] Figure 2 is a trajectory curve of the first trajectory data collected in the two-dimensional coordinate system in an embodiment of the present invention;

[0030] Figure 3 is a trajectory curve of second trajectory data of the contact edge between the measuring wheel and the rail to be measured in the embodiment of the present invention;

[0031] Figure 4 is a trajectory curve obtained after data preprocessing is performed on the first trajectory data or the second trajectory data in an embodiment of the present invention;

[0032] Figure 5 is a rail profile curve obtained by applying a rail profile measurement curve generation method of the present invention in an embodiment of the present invention;

[0033] Figure 6 1 is a schematic diagram of the principle of a rail head profile measuring instrument provided in an embodiment of the present invention;

[0034] Figure 7 It is a structural schematic diagram of a rail head profile measuring instrument (double measuring wheels) provided in an embodiment of the present invention;

[0035] Figure 8 It is a structural schematic diagram of a rail head profile measuring instrument (single measuring wheel) provided in an embodiment of the present invention.

[0036] In the figure:

[0037] 100. Rail to be tested;

[0038] 1. First encoder; 11. Base; 2. Second encoder; 3. Connecting rod; 4. Measuring arm; 5. Measuring wheel; 6. Reference seat. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0040] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0042] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning. The term "plurality" should be understood as more than two.

[0043] The present invention provides a method for generating a rail profile measurement curve, such as Figure 1 The flow chart shown, combined with Figure 2-Figure 7 , including the following steps:

[0044] S1, establishing a two-dimensional coordinate system with the highest point of the standard rail top as the coordinate origin, collecting first trajectory data of rail profile measurement and recording discrete data points of the first trajectory data in the two-dimensional coordinate system;

[0045] In the actual data collection process, the operator operates the measuring instrument to make the measuring wheel 5 roll along the rail head section of the steel rail 100 to be measured, and enters the automatic control to track the movement trajectory of the measuring wheel 5 and collect data. In this process, by setting a two-dimensional coordinate system, the rolling process of the measuring wheel 5 can be recorded to obtain the first trajectory data. When collecting data multiple times, additional trajectory data will appear due to human factors (such as hand shaking, repeated measurement of the profile of a certain area) or replacement of the measuring wheel 5, which will affect the final profile data calculation. Therefore, the first trajectory data needs to be processed. Figure 2 The figure shows a two-dimensional coordinate curve drawn based on the first trajectory data collected by a single measurement of the measuring wheel 5 .

[0046] S2, obtaining second trajectory data of the contact edge between the measuring wheel 5 and the rail 100 to be measured according to the diameter of the measuring wheel 5 and the first trajectory data;

[0047] The first trajectory data recorded by the rolling of the measuring wheel 5 in step S1 is the motion trajectory data of the center point M of the measuring wheel 5. In fact, it is the rim of the measuring wheel 5 that is in direct contact with the rail surface, not the center of the measuring wheel 5. Therefore, it is necessary to convert the motion trajectory data of the center point M of the measuring wheel 5 into the motion trajectory data of the rim of the measuring wheel 5. Specifically, it can be converted according to the diameter 2r of the measuring wheel 5, such as Figure 3 The figure shows a schematic diagram comparing the motion trajectories of the rim and the center of the measuring wheel 5 , and the envelopes of the two motion trajectories differ by a radius r of the measuring wheel 5 .

[0048] S3, drawing an envelope curve according to the second trajectory data, such as Figure 2 and Figure 3 shown.

[0049] S4, select a certain point in the enclosed area of ​​the envelope curve as the center O, select a certain length as the scanning radius L, and calculate the distance L' between the data point on the envelope curve and the center O. On the same scanning radius L, take the data point with the smallest distance L' as the valid data point, connect the valid data points in sequence, and obtain the rail profile curve, such as Figure 5 .

[0050] by Figure 2For example, first take a point in the envelope curve as the center O, calculate the distance L' between all data points on the envelope curve and the center O, and select the maximum value of the distance L', take the scanning radius L, the scanning radius L is not less than the maximum value of the distance L', the scanning radius L scans 360° around the center O, and finds valid data points on each scanning radius L. It should be noted that the scanning angle of the scanning radius L is selected according to the actual required calculation accuracy, the inflection point position can be scanned more densely, and the missing part on the envelope curve, or the part with a large difference in data, can be supplemented according to the moving average method.

[0051] A method for generating a rail profile measurement curve of the present invention records the collected first trajectory data in a two-dimensional coordinate system and draws a curve, and finally generates the required rail profile curve by searching the inner envelope method, thereby realizing rapid generation and calculation of the rail profile measurement curve with high accuracy. The method for generating the rail profile measurement curve has low technical requirements for operators and allows large errors in the process of collecting initial trajectory data, thereby greatly reducing the workload of operators and facilitating improving the efficiency of rail profile measurement.

[0052] Optionally, the two-dimensional coordinate system in step S1 is an XZ two-dimensional coordinate system in an XYZ three-axis coordinate system, the Y axis is along the long axis direction of the standard rail, and the XY two-dimensional coordinate system is a horizontal coordinate system.

[0053] For rail measurement, the same coordinate system is used for the rail 100 to be measured and the standard rail, which is conducive to the conversion of trajectory data and the comparison of trajectory data, so as to quickly obtain the detection result of the rail 100 to be measured. In the present invention, the highest point of the rail top surface is taken as the origin P, the Y axis is defined along the long axis direction of the standard rail, and the XY coordinate system is a horizontal coordinate system, that is, located in the XY plane, then the XZ two-dimensional coordinate system (located in the XZ plane) can be determined, and the first trajectory data of the measuring wheel is collected for rail profile generation.

[0054] Optionally, the first trajectory data in step S1 is obtained by measuring by rotating the measuring wheel 5 at least twice left and right.

[0055] In view of the fact that in the actual operation of rail measurement, due to the long rail, the measurement process may be interrupted, and the difference between operators may lead to large errors, the measuring wheel 5 can be repeatedly rolled to measure to enhance the reliability of the profile of the rail 100 to be measured. At the same time, for the double measuring wheel 5 structure, it is necessary to replace the rolling of the measuring wheel 5 on both sides of the rail 100 to be measured during multiple measurements, so as to obtain the detection data of both sides of the rail 100 to be measured and realize comprehensive detection of the rail 100 to be measured.

[0056] Optionally, the method for generating a rail profile measurement curve provided in this embodiment further includes a data preprocessing step before step S4: performing data preprocessing on the first trajectory data and / or the second trajectory data to obtain third trajectory data, drawing an envelope curve according to the third trajectory data, and then executing step S4.

[0057] From the motion trajectory of the center point M of the measuring wheel 5 in a single measurement ( Figure 2 ) can be clearly seen that in addition to the outer envelope of the target rail head profile, there are additional interference trajectory data during the operation process. Since the rail profile measuring instrument has no rigid requirements on the operator's operation process, these interference data have no specific rules and cannot be predicted. They cannot be eliminated by simple methods. Therefore, it is necessary to first pre-process the collected data through low-pass filtering to eliminate obvious useless data, and use the moving average method to smooth the fluctuations of the profile data, reduce the amount of calculation, and improve the efficiency of profile generation.

[0058] In this embodiment, as an optional solution, the second trajectory data of the rim of the measuring wheel 5 can be preprocessed, and the first trajectory data of the center point M of the measuring wheel 5 can also be preprocessed, which has the same effect of reducing the amount of calculation and improving the efficiency of generating the profile.

[0059] The low-pass filtering process needs to set a cutoff frequency according to the characteristics of the collected profile data. When the high-frequency signal exceeds the cutoff frequency, it will be blocked and weakened, thereby filtering out the noise data outside the profile data (first trajectory data or second trajectory data).

[0060] Moving average denoising is a moving average method that smoothes and denoises the first trajectory data or the second trajectory data. Assuming that the weights of all data are equal, the calculation formula for moving average denoising is as follows:

[0061] F t =(A t-1 +A t-2 +A t-3 +…+A t-n ) / n

[0062] In the formula, F t is the predicted value; n is the number of moving average data; A t-n The actual or calculated value of the first n data.

[0063] The edge track of the inner measuring wheel 5 (i.e., the area surrounded by the inner envelope) obtained through data preprocessing is the effective profile data and is also the area that needs to be scanned by the inner envelope. Figure 4 shown.

[0064] Optionally, in step S4, the scanning radius L is greater than the maximum value of the distance L', so as to obtain the distances L' corresponding to as many data points as possible during the scanning process.

[0065] Optionally, the first trajectory data in step S1 is obtained by a rail head profile measuring instrument, such as Figure 6 and Figure 7 As shown, the rail head profile measuring instrument includes an encoder, a measuring arm 4 and a host computer. There are two encoders, namely a first encoder 1 and a second encoder 2. The two encoders are connected by a connecting rod 3; one end of the measuring arm 4 is connected to one of the encoders ( Figure 7 The middle end is connected to the second encoder 2), and the other end is rotatably connected to the measuring wheel 5; the host computer is connected to the two encoders for communication, and the two encoders collect the rotation angles of the connecting rod 3 and the measuring arm 4 and upload them to the host computer.

[0066] It should be explained that when the measuring wheel 5 is rolling on the rail 100 to be measured, the first encoder 1 is set at the highest point of the rail 100 to be measured and can slide on the rail 100 to be measured during the rolling of the measuring wheel 5, playing a guiding role of the limit measuring wheel 5. Therefore, a base can be set on the first encoder 1 to be compatible with the rail 100 to be measured. During the rolling of the measuring wheel 5, the rotation angle θ2 of the measuring arm 4 relative to the vertical direction can be measured by the second encoder 2 and uploaded to the host computer, and the rotation angle θ1 of the connecting rod 3 relative to the vertical direction can be measured by the first encoder 1 and uploaded to the host computer. At the same time, during the measurement process, the angle ω between the measuring arm 4 and the connecting rod 3 is collected by the first encoder 1 or the second encoder 2 and uploaded to the host computer. The length L2 of the measuring arm 4 and the length L1 of the connecting rod 3 are preset values ​​and stored in the host computer.

[0067] Based on this, the horizontal and vertical coordinate values ​​of the first trajectory data can be obtained as:

[0068] X(M)=(L1-L2 cosω)sinθ1-L2 sinωcosθ1

[0069] Y(M)=-(L1-L2 cosω)cosθ1-L2 sinωsinθ1

[0070] Through the above structure, it is possible to set one or two measuring wheels 5 at the detection end of the measuring arm 4, that is, the end facing the rail 100 to be measured. Figure 7 As shown, the two measuring wheels 5 are symmetrically arranged in a herringbone shape on both sides of the long axis direction of the measuring support arm 4, as shown in FIG. Figure 8 As shown, a measuring wheel 5 is arranged at the end of the measuring arm 4, so as to facilitate the profile detection of both sides of the rail 100 to be measured. Figure 7 and Figure 8As shown, one end of the measuring arm 4 is rotatably connected to the second encoder 2, the second encoder 2 is rotatably connected to the first encoder 1, the first encoder 1 is arranged at the top of the to-be-measured rail 100 through a base 11, a reference seat 6 is arranged on the base 11, the reference seat 6 is a rod, during measurement, the two ends of the reference seat 6 are respectively arranged at the highest points of the two to-be-measured rails 100 for support, which can ensure the stable rolling of the measuring wheel 5 on the to-be-measured rail 100 to avoid overturning or deflection affecting the measurement, and the two ends of the reference seat 6 have the same counterweight.

[0071] Optionally, each measuring wheel 5 is provided with a magnetic member, which can be adsorbed on the rail 100 to be measured, so that a uniform adsorption force is generated between the rail 100 to be measured and the measuring wheel 5. The magnetic member preferably adopts a high-strength magnetic column structure for easy installation and adsorption.

[0072] After testing, it was found that the above inner envelope curve (i.e. rail profile measurement curve) generation method can scan and generate a rail head profile in no more than 1 second.

[0073] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for generating a rail profile measurement curve, characterized in that: The steps include: S1, establishing a two-dimensional coordinate system with the highest point of the standard rail top as the coordinate origin, collecting first trajectory data of rail profile measurement and recording discrete data points of the first trajectory data in the two-dimensional coordinate system; S2, obtaining second trajectory data of the contact edge between the measuring wheel (5) and the steel rail (100) to be measured according to the diameter of the measuring wheel (5) and the first trajectory data; the second trajectory data can be obtained by subtracting the radius of the measuring wheel (5) from the first trajectory data; S3, drawing an envelope curve according to the second trajectory data; S4, taking a certain point in the enclosed area of ​​the envelope curve as the center O, and calculating the distance L' between the data point on the envelope curve and the center O, selecting the maximum value of the distance L', and then taking a fixed length greater than the maximum value of the distance L' as the scanning radius L; on the same scanning radius L, taking the data point with the smallest distance L' as the valid data point, connecting the valid data points in sequence to obtain the rail profile curve.

2. The method for generating a rail profile measurement curve according to claim 1, characterized in that: The two-dimensional coordinate system in step S1 is the XZ two-dimensional coordinate system in the XYZ three-axis coordinate system, the Y axis is along the long axis direction of the standard rail, and the XY two-dimensional coordinate system is a horizontal coordinate system.

3. The method for generating a rail profile measurement curve according to claim 1, characterized in that: In step S1, the first trajectory data is obtained by rotating the measuring wheel (5) at least twice left and right.

4. The method for generating a rail profile measurement curve according to claim 1, characterized in that: Before step S4, a data preprocessing step is also included: performing data preprocessing on the first trajectory data and / or the second trajectory data to obtain third trajectory data, drawing the envelope curve according to the third trajectory data, and then executing step S4.

5. The method for generating a rail profile measurement curve according to claim 4, characterized in that: The data preprocessing is low-pass filtering denoising processing and / or moving average denoising processing.

6. The method for generating a rail profile measurement curve according to claim 1, characterized in that: The first trajectory data in step S1 is obtained by a rail head profile measuring instrument, and the rail head profile measuring instrument includes: Encoders, wherein two encoders are provided and the two encoders are connected via a connecting rod (3); A measuring arm (4), one end of the measuring arm (4) is connected to one of the encoders, and the other end is rotatably connected to the measuring wheel (5); A host computer is connected to the two encoders for communication, and the two encoders collect the rotation angles of the connecting rod (3) and the measuring support arm (4) and upload them to the host computer.

7. The method for generating a rail profile measurement curve according to claim 6, characterized in that: The first trajectory data is: X(M)=(L1-L2 cosω)sinθ1-L2 sinωcosθ1 Y(M)=-(L1-L2cosω)cosθ1-L2sinωsinθ1 Wherein, L1 and L2 are respectively the lengths of the connecting rod (3) and the measuring arm (4), ω is the angle between the measuring arm (4) and the connecting rod (3), θ1 is the rotation angle of the connecting rod (3) relative to the vertical direction, and θ2 is the rotation angle of the measuring arm (4) relative to the vertical direction.

8. The method for generating a rail profile measurement curve according to claim 6, characterized in that: Two measuring wheels (5) are provided, and the two measuring wheels (5) are symmetrically arranged in a herringbone shape on both sides of the long axis direction of the measuring support arm (4).

9. The method for generating a rail profile measurement curve according to claim 6, characterized in that: Each measuring wheel (5) is provided with a magnetic component, and the magnetic component can be adsorbed on the steel rail (100) to be measured.

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