A Method for Measuring the Straightness of Rail Based on an Adaptive Gravity Plane Ruler

Abstract

The present invention discloses a method for measuring the straightness of a rail based on an adaptive gravity plane ruler. The method for measuring the straightness of a rail based on an adaptive gravity plane ruler includes the following steps: establishing a world coordinate system XYZ, determining the length and width of the part of the rail to be measured; determining the length and width of the gravity plane ruler and dividing the gravity plane ruler into regions; finding three fulcrums on the top of the rail and calculating the straightness of the rail under the adaptive state. The method for measuring the straightness of a rail based on an adaptive gravity plane ruler can accurately measure the straightness of the rail in an abnormal state with high measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of rail measurement, and more specifically, to a method for measuring the straightness of rails based on an adaptive gravity flat ruler. Background Art

[0002] Currently, the most widely used method for measuring the straightness of rails in rail welding factories or rail factories is to place a flat ruler on the center tread of the rail or directly measure using an electronic straight ruler (such as the SEC-RC electronic ruler). This method for measuring the straightness of rails has relatively low measurement efficiency, cumbersome operation, and large human errors. With the rapid development of machine vision technology, the method for measuring the straightness of rails based on machine vision has become a trend. Its measurement method is roughly as follows: Use a sensor to measure the surface of the rail, extract the measurement points at the top of the rail, and connect them into a characteristic curve reflecting the top contour of the rail. Since there are methods such as the two-point connection method and the minimum zone method for measuring the straightness of rails based on machine vision, but these methods all have certain defects. The defect is that when the rail is in an abnormal state during the measurement process, Figure 1 FIG. shows a schematic diagram of the rail changing from the normal state A to the abnormal state B during the measurement process. For example, when the rail itself is distorted, specifically as Figure 1 shown. At this time, there are certain deficiencies in the measurement method and calculation method of using the sensor to measure the straightness of the rail, and there is a certain deviation in the measurement result, and the straightness of the rail cannot be accurately measured. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for measuring the straightness of rails based on an adaptive gravity flat ruler, to solve the deficiencies and defects existing in the methods for measuring the straightness of rails in existing rail welding factories or rail factories and the methods for measuring the straightness of rails using machine vision, and to be able to accurately measure the straightness of rails in an abnormal state with high measurement accuracy.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] As one aspect of the present invention, there is provided a method for measuring the straightness of rails based on an adaptive gravity flat ruler, including the following steps:

[0006] S1. Establish a world coordinate system XYZ, and determine the length and width of the part of the rail to be measured;

[0007] S2. Determine the length and width of the gravity flat ruler and divide the gravity flat ruler into regions;

[0008] S3. Find three fulcrums at the top of the rail and calculate the straightness of the rail under the adaptive state.

[0009] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, S1 includes the following steps:

[0010] S11. Establish a coordinate system XYZ to ensure that each measurement point on the steel rail has corresponding coordinate information in the coordinate system XYZ;

[0011] S12. Determine the length L0 and width W0 of the part to be measured in the steel rail.

[0012] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, S2 includes the following steps:

[0013] S21. Determine the length and width of the gravity plane ruler to be consistent with the length and width of the part to be measured of the steel rail;

[0014] S22. Divide the gravity plane ruler into four equal - part regions, and determine the center - of - gravity point, the transverse center - of - gravity line, and the longitudinal center - of - gravity line.

[0015] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, S22 includes the following steps:

[0016] S221. Each two adjacent regions in the four equal - part regions are separated by the transverse center - of - gravity line and the longitudinal center - of - gravity line;

[0017] S222. The intersection point of the transverse center - of - gravity line and the longitudinal center - of - gravity line is the center - of - gravity point of the entire gravity plane ruler.

[0018] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, S3 includes the following steps:

[0019] S31. Eliminate the invalid algorithms and find three fulcrums on the top of the steel rail;

[0020] S32. Wait for the adaptive state of the gravity plane ruler, and calculate the plane equation of the gravity plane ruler according to the coordinates of the three fulcrums;

[0021] S33. Project the top of the steel rail and the gravity plane ruler along the vertical direction, and calculate the straightness.

[0022] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, S31 includes the following steps:

[0023] S311. Eliminate the invalid algorithms for steel rails that do not meet the measurement requirements;

[0024] S312. Sequentially find three fulcrums on the top of the steel rail.

[0025] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, wherein S311 includes the following steps:

[0026] S3111. If there is exactly one point on the measured part of the steel rail surface that coincides with the center of gravity of the gravity plane, this algorithm is invalid;

[0027] S3112. If only the line segment connecting two points on the opposite sides of the steel rail surface coincides with the center of gravity of the gravity plane, this algorithm is invalid.

[0028] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, wherein S312 includes the following steps:

[0029] S3121. Place the gravity plane ruler along the end of the steel rail and find the first support point Pf until the gravity plane ruler touches the second support point Ps in the remaining area;

[0030] S3122. If the first support point and the second support point are in the same upper and lower area or the same left and right area, then find the third support point Pth in the opposite area;

[0031] S3123. If the first support point and the second support point are in the relative area, connect the first support point and the second support point, and find the third support point in the remaining area outside the connection line of the two.

[0032] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, wherein each point in S32 corresponds to a world coordinate, that is, the first support point Pf(x 1 y 1 z 1 ), the second support point Ps(x 2 y 2 z 2 ), the third support point Pth(x 3 y 3 z 3 ), and calculate the gravity flat ruler plane equation of the plane where the three points are located as follows:

[0033] Ax + By + Cz + D = 0

[0034] Where:

[0035] A = (y 3 - y 1 )·(z 3 - z 1 ) - (z 2 - z 1 )·(y 3 - y 1 )

[0036] B = (x 3 - x 1 )·(z 2 - z 1 ) - (x 2 - x 1 )·(z 3 - z 1 )

[0037] C = (x 2 - x 1 )·(y 3 - y 1 ) - (x 3 - x 1 )·(y 2 - y 1 )

[0038] D = -(A·x 1 + B·y 1 + C·z 1 )

[0039] As a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler in the above aspect of the present invention, S33 includes the following steps:

[0040] S331. Project all the points on the top of the steel rail along the direction perpendicular to the plane into a two-dimensional coordinate system. In the projected two-dimensional coordinate system, the plane is a straight line, and all the points on the top of the steel rail are irregular curves;

[0041] S332. If there are defects on the top of the steel rail, calculate the extreme distance Dmax from the curve to the straight line.

[0042] Adopting the above technical solutions, the present invention has the following advantages:

[0043] The present invention provides a method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler. By establishing a coordinate system of the steel rail to be measured and calculating the straightness of the steel rail in an adaptive state, it solves the technical problem of measurement deviation in the non-normal state during the measurement process of the existing methods for measuring the straightness of a steel rail in a steel rail welding factory or a steel rail factory, which place a flat ruler on the center tread of the steel rail or directly measure using an electronic straight ruler (such as a SEC-RC electronic ruler), and the method for measuring the straightness of a steel rail using machine vision. It can accurately measure the straightness of the steel rail with high measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other features, objects, and advantages of the present invention will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings.

[0045] Figure 1It is a schematic structural diagram of the rail itself being distorted during the measurement process;

[0046] Figure 2 It is the schematic principle diagram of using the gravity flat ruler of the present invention to measure the straightness of the rail;

[0047] Figure 3 It is the flow chart of the algorithm for using the gravity flat ruler of the present invention to measure the straightness of the rail;

[0048] Figure 4 It is the schematic diagram of setting the parameters of the gravity flat ruler in the present invention;

[0049] Figure 5a It is the schematic diagram of an algorithm for excluding invalid ones in the present invention;

[0050] Figure 5b It is the schematic diagram of another algorithm for excluding invalid ones in the present invention;

[0051] Figure 6a It is the schematic diagram of finding the first support point in one case of the present invention;

[0052] Figure 6b It is the schematic diagram of finding the first support point in another case of the present invention;

[0053] Figure 7a It is the schematic diagram of finding the second support point in the present invention;

[0054] Figure 7b It is the schematic diagram of finding the second support point in the present invention;

[0055] Figure 7c It is the schematic diagram of finding the third support point in the present invention;

[0056] Figure 8a It is the schematic diagram of the plane projection of the three support points in the present invention;

[0057] Figure 8b It is the schematic diagram of using the gravity flat ruler to obtain the straightness of the rail in the present invention. Detailed implementation manners

[0058] The technical solution of the present invention will be specifically described below in conjunction with the accompanying drawings of the specification. The detailed features and advantages of the present invention will be described in detail in the specific implementation manners. The content is sufficient for any person skilled in the art to understand the technical content of the present invention and implement it accordingly. According to the specification, claims and drawings disclosed in this specification, those skilled in the art can easily understand the relevant purposes and advantages of the present invention.

[0059] Figure 2 It shows the schematic principle diagram of using the gravity flat ruler to measure the straightness of the rail in the present invention; Figure 3The flowchart of the algorithm for measuring the straightness of the rail using the gravity plane ruler according to the present invention is shown.

[0060] According to the provisions of TB / T2344-2012, taking the top of a 1.5m long rail as an example, the 1.5m long gravity plane ruler 2 is placed on the surface of the rail 1, the end of the gravity plane ruler 2 is aligned with the end of the rail 1, and the rest is symmetrically placed on the rail 1. After the gravity plane ruler 2 reaches the adaptive state, that is, after the gravity plane ruler 2 is relatively stationary with the rail 1, the distance between the rail 1 and the gravity plane ruler 2 is measured. The maximum value of the distance between the two is the straightness of the top of the 1.5m long rail. The specific measurement principle diagram is as Figure 2 shown.

[0061] The present invention provides a method for measuring the straightness of a rail based on an adaptive gravity plane ruler, specifically as Figure 3 shown, including the following steps:

[0062] S1. Establish a world coordinate system XYZ, and determine the length and width of the part of the rail to be measured;

[0063] Among them, S1 includes the following steps:

[0064] S11. Establish a world coordinate system XYZ. The world coordinate system XYZ can be established anywhere because the calculation result is a relative value, that is, the maximum distance from the gravity flat ruler to the top of the rail. However, for the convenience of calculation, a world coordinate system is established based on the bottom plane of the rail and the rail height to ensure that each measurement point on the rail has corresponding coordinate information in the coordinate system XYZ, that is, all parts of the rail are within the coordinate system, and each measurement point corresponds to a coordinate information;

[0065] S12. Determine the length L0 and width W0 of the part to be measured in the rail. The part to be measured can be adjusted according to the on-site needs. The length and width of the gravity flat ruler are the same as those of the top of the rail and are determined with the determination of the parameters of the top of the rail.

[0066] Figure 4 is a schematic diagram of setting the parameters of the gravity plane ruler in the present invention.

[0067] S2. Determine the length and width of the gravity plane ruler and divide the gravity plane ruler into regions;

[0068] Among them, S2 includes the following steps:

[0069] S21. Determine the length and width of the gravity plane ruler, which are the same as the length and width of the part of the rail to be measured and are determined with the determination of the parameters of the top of the rail.

[0070] S22. Set the parameters of the gravity plane ruler, and divide the gravity plane ruler determined in step S21 into four equal parts of regions. Specifically as Figure 4As shown, there are a first region, a second region, a third region, and a fourth region respectively. Among them, the lengths of the first region, the second region, the third region, and the fourth region are all L / 2, and the widths are all W / 2.

[0071] Among them, S22 includes the following steps:

[0072] S221. Each two adjacent regions among the four equal - divided regions are separated by the center - of - gravity lines (the horizontal center - of - gravity line c1 and the vertical center - of - gravity line c2);

[0073] S222. The intersection point of the two center - of - gravity lines is the center - of - gravity point (c0) of the entire straightedge, which divides the gravity straightedge into four equal - divided regions, and determines the center - of - gravity point, the horizontal center - of - gravity line, and the vertical center - of - gravity line.

[0074] S3. Find three fulcrums on the top of the rail and calculate the straightness of the rail under the adaptive state.

[0075] Among them, S3 includes the following steps:

[0076] S31. Eliminate the invalid algorithm and find three fulcrums on the top of the rail;

[0077] Among them, S31 includes the following steps:

[0078] S311. Eliminate the invalid algorithm of the rail that does not meet the measurement requirements;

[0079] S311 specifically includes the following steps:

[0080] S3111. If there is exactly one point among all the points on the measured part of the rail surface that coincides with the center - of - gravity of the gravity plane, that is, the first support point Pf found coincides with the center - of - gravity c of the gravity plane, as specifically shown in Figure 5a As shown, the algorithm of this rail is invalid;

[0081] S3112. If the line segment connecting only the two points on the opposite sides (the first support point Pf and the second support point Ps) of the rail surface coincides with the center - of - gravity c of the gravity plane, that is, the line connecting the first support point and the second support point passes through the center - of - gravity of the gravity plane, as specifically shown in Figure 5b As shown, the algorithm of this rail is invalid.

[0082] S312. Find three fulcrums on the top of the rail in sequence.

[0083] Among them, S312 specifically includes the following steps:

[0084] S3121. Place the gravity straightedge along the end of the rail and find the first support point Pf. The first support point Pf may be in any one of the four regions. Assume that the first support point Pf is located in the second region. At this time, due to the action of gravity, the gravity straightedge will tilt towards the other three regions, as specifically shown in Figure 6aAs shown, if the first support point Pf lies on the center of gravity line, it is considered that the support point is in two regions. Due to the action of gravity, the gravity plane ruler will tilt towards the other two regions, specifically as Figure 6b shown.

[0085] S3122. After the step of finding the first support point Pf in step S3121, until the gravity plane touches the second support point Ps in the remaining region. At this time, judge the regions where the first support point Pf and the second support point Ps are located. If the first support point Pf and the second support point Ps are in the same upper and lower region or the same left and right region, then find the third support point Pth in the opposite region, specifically as Figure 7a 、 Figure 7b shown;

[0086] S3123. If the first support point Pf and the second support point Ps are in the relative regions, connect the first support point Pf and the second support point Ps, and find the third support point Pth in the remaining region outside the connection line between the two, specifically as Figure 7c shown.

[0087] S32. Wait for the gravity plane ruler to be in the adaptive state, and calculate the gravity flat ruler plane equation according to the coordinates of the three support points;

[0088] Since the XYZ surface data is in the world coordinate system XYZ, each point on the rail corresponds to a world coordinate, that is, the first support point Pf(x 1 y 1 z 1 ), the second support point Ps(x 2 y 2 z 2 ), the third support point Pth(x 3 y 3 z 3 ). The plane equation of the plane where the three support points are located can be obtained and expressed in the general form:

[0089] Ax + By + Cz + D = 0 (1)

[0090] Among them:

[0091] A = (y 3 - y 1 )·(z 3 - z 1 ) - (z 2 - z 1 )·(y 3 - y 1 )

[0092] B = (x 3 - x 1 )·(z 2 - z 1)-(x 2 -x 1 )·(z 3 -z 1 )

[0093] C = (x 2 -x 1 )·(y 3 -y 1 )-(x 3 -x 1 )·(y 2 -y 1 )

[0094] D = -(A·x 1 + B·y 1 + C·z 1 ) (2)

[0095] S33. Project the top of the rail and the gravity level along the vertical direction to calculate the straightness.

[0096] Among them, S33 includes the following steps:

[0097] S331. After obtaining the above plane equation, all the points on the top of the rail are projected along the direction perpendicular to the plane into a new two-dimensional coordinate system, specifically as Figure 8a shown. The projected plane is a straight line c in the two-dimensional coordinate system, and all the points on the top of the rail are projected into an irregular curve d in the coordinate system, specifically as Figure 8b shown. In Figure 8b , the darker the color, the denser the data, and the lighter the color, the sparser the data.;

[0098] S332. If there are defects on the top of the rail, calculate the maximum distance Dmax from the curve d to the straight line c, specifically as Figure 8b shown, which is the straightness of the rail measured by the gravity level ruler based on the adaptive state.

[0099] Finally, it should be noted that although the present invention has been described with reference to the current specific embodiments, those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Various equivalent changes or substitutions can be made without departing from the concept of the present invention. Therefore, as long as the changes and modifications of the above embodiments are within the scope of the spirit of the present invention, they will fall within the scope of the claims of the present invention.

Claims

1. A method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler, characterized in that, it includes the following steps: S1. Establish a world coordinate system XYZ, and determine the length and width of the part of the steel rail to be measured. Step S1 includes: S11. Establish a coordinate system XYZ to ensure that each measurement point on the steel rail has corresponding coordinate information in the coordinate system XYZ; S12. Determine the length L0 and width W0 of the part to be measured in the steel rail; S2. Determine the length and width of the gravity plane ruler and divide the gravity plane ruler into regions. Step S2 includes: S21. Determine the length and width of the gravity plane ruler, which are the same as the length and width of the part of the steel rail to be measured; S22. Divide the gravity plane ruler into four equal regions, and determine the center of gravity point, the transverse center of gravity line, and the longitudinal center of gravity line; S3. Find three support points on the top of the steel rail, and calculate the straightness of the steel rail under the adaptive state. Step S3 includes: S31. Eliminate invalid algorithms and find three support points on the top of the steel rail; S32. Wait for the adaptive state of the gravity plane ruler, and calculate the plane equation of the gravity flat ruler according to the coordinates of the three support points; S33. Project the top of the steel rail and the gravity flat ruler along the vertical direction, and calculate the straightness, Step S31 includes: S311. Eliminate the invalid algorithms of the steel rails that do not meet the measurement requirements; S312. Find three support points on the top of the steel rail in turn, Step S311 includes: S3111. If there is only one point on all the measured points on the surface of the steel rail that coincides with the center of gravity of the gravity plane, this algorithm is invalid; S3112. If only the line segment connecting the two points on the opposite sides of the surface of the steel rail coincides with the center of gravity of the gravity plane, then this algorithm is invalid, Step S312 includes: S3121. Place the gravity plane ruler along the end of the steel rail, and find the first support point Pf until the gravity plane ruler touches the second support point Ps in the remaining area; S3122. If the first support point and the second support point are in the same upper and lower area or the same left and right area, then find the third support point Pth in the opposite area; S3123. If the first support point and the second support point are in the relative area, connect the first support point and the second support point, and find the third support point in the remaining area outside the connection line of the two.

2. A method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler according to claim 1, characterized in that, the said S22 includes the following steps: S221. Each two adjacent regions in the four equal regions are separated by the transverse center of gravity line and the longitudinal center of gravity line; S222. The intersection point of the transverse center of gravity line and the longitudinal center of gravity line is the center of gravity point of the entire gravity plane ruler.

3. A method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler according to claim 1, characterized in that, Each point in S32 corresponds to a world coordinate, i.e., the first support point , the second support point , the third support point . The gravity leveling plane equation of the plane where the three points are located is as follows: Wherein: 。 4. A method for measuring the straightness of a steel rail based on an adaptive gravity plane ruler according to claim 1, characterized in that, the said S33 includes the following steps: S331. Project all the points on the top of the steel rail along the direction perpendicular to the plane into a two-dimensional coordinate system. In the projected two-dimensional coordinate system, the plane is a straight line, and all the points on the top of the steel rail are irregular curves; S332. If there are defects at the top of the rail, calculate the extreme distance Dmax from the curve to the straight line.

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