CN112284256B - Method and system for measuring plane abrasion of workpiece - Google Patents
Method and system for measuring plane abrasion of workpiece Download PDFInfo
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- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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- G—PHYSICS
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
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Abstract
The embodiment of the invention relates to a method and a system for measuring the plane abrasion of a workpiece, wherein the method comprises the following steps: projecting a laser line to a plane of a workpiece to be detected, and acquiring an image containing the laser line; acquiring point cloud data related to the laser line according to the image; determining a consistency point set DSn located in a wear area in the point cloud data; wherein DSn is a subset of Dn; fitting a reference line f (x, y) for representing a wear area according to the consistency point set; determining a rotation reference line f '(x', y ') such that the slope of the rotation reference line f' (x ', y') with respect to the x-axis is within an interval including 0, from the slope of the reference line f (x, y) with respect to the x-axis; and determining the abrasion degree of the plane of the workpiece to be measured according to the rotating reference line. The embodiment of the invention can accurately measure the non-wear points and the wear areas, thereby improving the measurement accuracy of the wear degree of the plane of the workpiece.
Description
Technical Field
The embodiment of the invention relates to the technical field of workpiece measurement, in particular to a method and a system for measuring the plane abrasion of a workpiece.
Background
Workpieces that are in contact and move relative to each other are often subject to wear, for example, between a brake disc and a brake pad, and triangulation laser ranging can be used to detect such wear. The specific detection principle is as follows: monocular laser rangefinder shoots target laser line at first through the camera, then, extracts out the laser line from the camera image, converts image pixel coordinate into 3D point cloud data through projection transformation, and follow the measuring distance information of the target of the inside analysis of point cloud data again. In point cloud data analysis, the positions of unworn points are usually used as reference points, and the laser projection depth difference between a worn area and the reference points is compared to obtain wear information.
Since the determination mode of the wear area in the point cloud data affects the accuracy of measuring the wear information of the brake disc, how to accurately determine the wear area becomes a technical problem to be solved urgently by those skilled in the art.
Disclosure of Invention
The embodiment of the invention aims to provide a method and a system for measuring the plane abrasion of a workpiece, which can accurately measure the non-abrasion point and the abrasion area, thereby improving the measurement accuracy of the plane abrasion degree of the workpiece.
In a first aspect, an embodiment of the present invention provides a method for measuring a wear of a plane of a workpiece, where the method includes:
projecting a laser line to a plane of a workpiece to be detected, and acquiring an image containing the laser line;
acquiring point cloud data related to the laser line according to the image; the point cloud data is a coordinate data sequence D of the laser line projected on the plane of the workpiece to be detectedn(ii) a Wherein D isn＝{d1(x1,y1)……dn(xn,yn) N is a positive integer, dn(xn,yn) Representing the laser spot d on said laser linenCoordinates, x, projected on the plane of the workpiece to be inspectednIndicating the laser spot d with the length direction of the laser line as the x-axisnCorresponding x-axis coordinate, ynIndicating a laser point d when the depth direction of the laser line on the plane of the workpiece to be detected is taken as a y-axisnCorresponding y-axis coordinates;
determining a set of consistency points DS located in a wear region in the point cloud datan(ii) a Wherein, DSnIs DnA subset of (a);
fitting a reference line f (x, y) for representing a wear area according to the consistency point set;
determining a rotation reference line f '(x', y ') such that the slope of the rotation reference line f' (x ', y') with respect to the x-axis is within an interval including 0, from the slope of the reference line f (x, y) with respect to the x-axis;
and determining the abrasion degree of the plane of the workpiece to be measured according to the rotating reference line.
In some embodiments, the determining the rotation reference line is calculated according to a rotation formula, the rotation formula being:
wherein,
coordinates of each point in the rotation reference line f ' (x ', y '),
is the coordinate of each point in the reference line f (x, y), k is the slope of the reference line f (x, y) with respect to the x-axis, and θ is the angle of rotation of the reference line f (x, y) with respect to the x-axis.
In some embodiments, the determining the wear level of the plane of the workpiece to be measured according to the rotation reference line includes:
determining an unworn point in the area where the rotating reference line is located;
and determining the wear depth according to the unworn point and the rotation reference line.
In some embodiments, said determining an unworn point in a region where said rotating reference line is located comprises:
searching the lowest point of the area lower than the rotation reference line as an unworn point.
In some embodiments, said determining a wear depth from said unworn point and said rotating reference line comprises:
searching from the unworn point to the center of the consistency point set, and taking a point in a preset range of the rotating reference line as a wear point;
and determining the wear depth according to the wear point and the unworn point.
In some embodiments, said determining a wear depth from said wear point and said unworn point comprises:
determining at least one wear level of a maximum wear level, an average wear level, or a wear consistency from the unworn point and the wear point.
In some embodiments, the determining wear consistency comprises:
determining a wear area according to the wear point;
determining the abrasion consistency information according to the curvature of the reference line and the discreteness of the point set corresponding to the abrasion area;
outputting the wear consistency information.
In some embodiments, the determining the maximum degree of wear comprises:
acquiring coordinate information of the wear point;
when the ordinate of the abrasion point is the maximum value, determining the abrasion point as the maximum abrasion point;
and outputting the coordinate information corresponding to the maximum abrasion point as maximum abrasion information.
In some embodiments, after said determining a wear depth from said unworn point and said rotating reference line, said method further comprises:
and when the wear depth exceeds the preset wear degree, outputting prompt information for prompting a user to replace the workpiece to be detected.
In some embodiments, the determining a set of consistent points located in a wear region in the point cloud data comprises:
searching continuous sections with loss functions smaller than a preset value and in accordance with a preset length in the point cloud data as a bus;
extending a consistent point according to the bus;
removing singular points in the consistent points to obtain an initial point set;
performing consistency evaluation on the initial point set by using the loss function;
when the initial point set passes the consistency assessment, the initial point set is used as the consistency point set.
In some embodiments, the finding a continuous segment with a loss function smaller than a preset value and conforming to a preset length in the point cloud data as a generatrix comprises:
and in the point cloud data, searching continuous sections with loss functions smaller than a preset value and in accordance with a preset length from the center to the two ends of the point cloud data or from the two ends of the point cloud data to the center to serve as a bus.
In some embodiments, said extending a consistent point according to said bus bar comprises:
calculating the Euclidean distance from a point in the preset range of the bus to the bus in the preset range of the bus;
and if the Euclidean distance is smaller than the preset distance, combining the corresponding point with the bus to obtain a consistent point.
In some embodiments, the removing singular points from the consistent points to obtain an initial point set includes:
and eliminating at least one singular point including a discrete point and a hole twill interference point in the consistent points to obtain the initial point set.
In a second aspect, embodiments of the present invention provide a system for measuring wear of a plane of a workpiece, the system comprising:
a support;
the laser is fixed on the support and projects laser lines to the plane of the workpiece to be detected;
the camera is fixed on the bracket and used for acquiring an image containing the laser line;
at least one processor, and
a memory communicatively coupled to the at least one processor, the memory storing instructions executable by the at least one processor to enable the at least one processor to perform any of the methods described above.
In a third aspect, embodiments of the present invention provide a non-transitory computer-readable storage medium having stored thereon computer-executable instructions that, when executed by a workpiece plane wear measurement system, cause the workpiece plane wear measurement system to perform a method as described above.
According to the method and the system for measuring the plane abrasion of the workpiece, disclosed by the embodiment of the invention, a laser measurement technology is adopted, a consistency point set located in an abrasion area is determined in point cloud data, and a reference line used for representing the abrasion area is fitted according to the consistency point set, so that the reference line is effectively and accurately measured; determining a rotating reference line according to the slope of the reference line relative to the x axis, so that the slope of the rotating reference line relative to the x axis is within an interval containing 0, and effectively and accurately rotating the reference line; and fitting the wear area according to the rotating reference line, and determining the wear degree of the plane of the workpiece to be measured, so that the measurement precision is greatly improved.
Drawings
One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.
FIG. 1 is a schematic diagram of a system for measuring the planar wear of a workpiece according to an embodiment of the present invention;
FIG. 2 is a schematic flow chart diagram illustrating a method for measuring the planar wear of a workpiece according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a laser line image of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 4a is a schematic structural diagram of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 4b is a schematic structural diagram of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 5 is a schematic structural view of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 6a is a schematic structural diagram of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 6b is a schematic structural diagram of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 7a is a schematic structural view of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 7b is a schematic structural diagram of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 7c is a schematic structural view of an embodiment of the method for measuring the planar wear of a workpiece according to the present invention;
FIG. 8 is a schematic structural view of an embodiment of the method for measuring the flat wear of a workpiece according to the present invention;
fig. 9 is a schematic diagram of a hardware configuration of a controller in an embodiment of the system for measuring the wear of the flat surface of the workpiece according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
The embodiment of the invention provides a structural schematic diagram of a measuring system for workpiece plane abrasion. As shown in FIG. 1, a workpiece plane wear measurement system 10 includes a support; the laser 14 is fixed on the support, and the laser 14 projects laser lines to the plane of the workpiece to be detected;
a camera 15 fixed on the support, the camera 15 being used to collect an image containing the laser line.
The workpiece plane wear measurement system 10 may further include a display device 16 for displaying a degree of wear;
and the power supply 17 is used for supplying power to the laser 14, the camera 15 and the master control center.
It can be understood that the system 10 for measuring the plane wear of the workpiece can be implemented in various environments such as a PC, an embedded system, a handheld device, an industrial controller, etc., and the system 10 for measuring the plane wear of the workpiece is provided with a controller as a main control center to accurately measure the non-wear point and the wear area, thereby improving the measurement accuracy of the plane wear degree of the workpiece.
Referring to fig. 2, fig. 2 is a schematic flow chart of a method for measuring wear of a flat surface of a workpiece according to an embodiment of the present invention, which can be executed by the controller 13 in the system 10 for measuring wear of a flat surface of a workpiece, and the method includes:
101: and projecting a laser line to a plane of the workpiece to be detected, and acquiring an image containing the laser line.
When the workpiece to be detected is subjected to workpiece plane abrasion measurement, a laser is utilized to project a laser line to the workpiece plane to be detected, and a camera is utilized to collect an image containing the laser line. Wherein the workpieces to be detected comprise brake discs and other workpieces with wear characteristics after long-term use. The surface to be detected in the workpiece to be detected is substantially planar.
102: acquiring point cloud data related to the laser line according to the image; the point cloud data is a coordinate data sequence Dn of the laser line projected on the plane of the workpiece to be detected; wherein Dn is { d ═ d1(x1,y1)……dn(xn,yn) N is a positive integer, dn(xn,yn) Representing the laser spot d on said laser linenCoordinates, x, projected on the plane of the workpiece to be inspectednIndicating the laser spot d with the length direction of the laser line as the x-axisnCorresponding x-axis coordinate, ynIndicating a laser point d when the depth direction of the laser line on the plane of the workpiece to be detected is taken as a y-axisnCorresponding y-axis coordinate.
In some embodiments, an image containing a laser line is acquired as shown in FIG. 3, the image including a black background region and a highlighted laser line region distinct from the black background region, and point cloud data representing the coordinates of the laser line is determined from the highlighted laser line region.
In some embodiments, the highlighted laser line area may be divided into an edge area and a measurement area, and the edge area may also be referred to as an edge interference area, as shown in fig. 4a, where the laser line of the edge area does not contribute to the measurement of the wear level of the workpiece to be detected, and if the laser line of the edge area is considered, the measurement accuracy may be affected, so that the laser line area may be further processed, the edge area may be identified and removed, and only the measurement area may be reserved for subsequent wear level determination. The pixel points of the eliminated edge area can utilize a neighboring point distance judgment method, a sorting method, a springback detection method and the like.
Specifically, in the adjacent point distance determination method, since the edge area and the measurement area are relatively far away from each other in the laser line projection direction and are relatively severely changed, in the point cloud data acquired in the laser line area, the edge area is usually relatively far away from the measurement area, and the distance inside the measurement area is usually relatively small, so that the edge area can be separated by the distance difference.
In the sorting method, since the order of coordinates of points in the abscissa direction of the edge segment is not consistent with the order of point sets in the abscissa direction of the measurement area, the edge segment can be separated by this characteristic, as shown in fig. 4a, the edge segment on the left side is separated.
The springback detection method, as shown in fig. 4b, the first lowest point below the reference line is not usually a reference point, but is interference data generated by edge interference in the background laser line, and needs to be eliminated.
After the edge interference data are removed, the position of the effective reference point close to the center of the point cloud can be judged, the characteristic of large springback is provided in the vertical coordinate direction, and the effective reference point in fig. 4b can be identified according to the characteristic.
As shown in the right side of fig. 6b, there are also incomplete reference points, when the reference points are not completely photographed, the point cloud data is incomplete and has a defect, the positions of the incomplete reference points are usually located at the edge of the point cloud data sequence, the longitudinal distance between the points is relatively large, the number of adjacent points is relatively small, the incomplete reference points can be identified according to the above features, and after the incomplete reference points are identified, the incomplete reference points cannot be used as reference points for point cloud wear detection, and also need to be removed.
In fig. 4a and 4b, the images are mapped to the coordinate system with the abscissa being the length direction of the laser line and the ordinate being the depth of the laser line in the plane of the workpiece to be detected. After the measuring area is determined, only the image of the measuring area can be processed and analyzed, and the point cloud data of the laser line of the measuring area mapped in the coordinate system is determined. Specifically, for example, a gray scale gravity center method may be used to analyze the pixel coordinates of the laser line in the measurement area, and the calculation formula of the pixel coordinates refers to formula 1:
wherein W (i, j) represents the gray scale weight of an image pixel, i, j represent the horizontal coordinate and the vertical coordinate of the pixel respectively, S represents the target area, S (x)0，y0) And k is a positive integer and represents the kth point.
The gray scale gravity center method can be regarded as a weighted centroid method with the gray scale square as a weight value, and has good positioning effect when a target and a background have large gray scale difference by utilizing the gray scale gravity center method without carrying out binarization on an image.
It is understood that the extraction of the laser line is not limited to the extraction by the gray scale gravity center method, and other methods other than the gray scale gravity center method, such as the centroid method, may also be adopted.
Extracting pixel coordinates S (x) from the image0，y0) And then, converting the pixel coordinate into a camera coordinate through projection transformation, so as to convert the pixel coordinate into a coordinate where the laser line is located, and referring to formula 2:
wherein,
three coordinates representing the camera coordinates in the 3D plane, a representing the camera reference matrix, C representing the camera coordinates, u representing the pixel coordinates lateral direction, v representing the pixel coordinates longitudinal direction, and u and v both being scalars.
The projective transformation direction can be changed with the reference point above and the wear zone below, as shown in fig. 7 a.
After the camera coordinates are obtained, the camera coordinates are converted into laser coordinates as shown in equation 3:
wherein,
three coordinates representing the coordinate system of the camera,
three coordinates representing a laser coordinate system, R representing a rotation change matrix, C representing a camera coordinate system, L representing the laser coordinate system, and the camera coordinate system coinciding with the origin of coordinates of the laser coordinate system.
After the conversion into the laser coordinate, because the point cloud data is the 3D laser coordinate system, based on the 3D laser coordinate system, only the coordinates of the laser line direction and the laser projection direction are reserved to obtain 2D point cloud data, as shown in fig. 5, a coordinate data sequence D of the laser line projected on the workpiece plane to be detected is obtainedn(ii) a Wherein Dn ═ d1(x1,y1)……dn(xn,yn) N is a positive integer, dn(xn,yn) Representing the laser spot d on said laser linenCoordinates, x, projected on the plane of the workpiece to be inspectednIndicating the laser spot d with the length direction of the laser line as the x-axisnCorresponding x-axis coordinate, ynIndicating a laser point d when the depth direction of the laser line on the plane of the workpiece to be detected is taken as a y-axisnCorresponding y-axis coordinates. For example, as shown in fig. 5, the horizontal direction indicates the x-axis direction, and the vertical direction indicates the y-axis direction. For example, the mapping relationship from the image to the horizontal and vertical coordinates in fig. 4a or the coordinate graph in fig. 4b may be understood as a point cloud graph of the point cloud data or a coordinate graph of the point cloud data, which is used to indicate the horizontal and vertical coordinate values of the point cloud data.
103: determining a set of consistency points DS located in a wear region in the point cloud datan(ii) a Wherein, DSnIs DnA subset of (a).
As shown in fig. 5, since there may be an inclination in the shooting angle of the camera, in the point cloud image, the point cloud is not parallel to the abscissa axis in the abscissa direction, and it is difficult to find the measurement point and the reference point from the original point cloud data, it is necessary to rotate the point cloud data to be parallel to the abscissa.
In some embodiments, the determining a set of consistent points located in a wear region in the point cloud data comprises:
31: and searching continuous sections with loss functions smaller than a preset value and in accordance with a preset length in the point cloud data as a bus.
When a bus is explored, because the wear degrees of most positions are relatively close in a wear area, the points can be considered to be near a certain straight line, and continuous sections with loss functions smaller than a preset value and in accordance with a preset length can be searched from the center of the point cloud data to two ends or from the two ends of the point cloud data to the center in the point cloud data to serve as the bus.
Specifically, the loss function is calculated according to equation 4:
wherein m and n are positive integers, the mth groove is represented, n points are provided, the shortest average Euclidean distance between a calculated point and a straight line is used as an evaluation criterion, k represents the slope of a point set fitting straight line, and the fitting straight line is represented by y-kx + b point skew. A generatrix is generally preferred to a point near the center of the point cloud location because the location is generally worn to a relatively close degree. If no suitable bus can be searched near the center of the wear area, searching can be respectively carried out from two ends of the point cloud data. The initial length of the bus is also critical, if the initial length is too short, the consistency is not good, if the initial length is too long, the probability of search failure is high, and the preset length is 10 mm.
32: and expanding consistent points according to the bus.
In some embodiments, the bus expansion consistency may include:
calculating the Euclidean distance from a point in the preset range of the bus to the bus in the preset range of the bus;
and if the Euclidean distance is smaller than the preset distance, combining the corresponding point with the bus to obtain a consistent point.
A search range can be defined as a preset range of the bus, then, the Euclidean distance from a point in the preset range to the bus is calculated, if the Euclidean distance is smaller than the preset distance, the corresponding point is combined with the bus, and if the Euclidean distance is larger than the preset distance, the point is far away, and the points are crossed.
And searching a point which is in a preset range and has better consistency with the bus according to the Euclidean distance and the preset distance, thereby effectively expanding the consistent point.
It is understood that other methods of non-average euclidean distance may be used in extending the consistent point, and that all such methods are simple variations and transformations of the present application as long as they are effective in extending the consistent point and fall within the scope of the present application.
33: and eliminating singular points in the consistent points to obtain an initial point set.
In practical applications, the worn area may include singular points such as holes, patterns, or edge reflections, all of which cause distortion of the point cloud data. Therefore, when consistency points are searched, at least one singular point including a discrete point and a hole twill interference point in the consistency points is removed to obtain the initial point set.
As shown in fig. 6a and 7c, the point cloud data may be erroneously determined as a reference point due to the non-uniform plane of the workpiece to be detected, the reflection of the target, the clutter, etc., so that the point cloud data needs to be removed when being analyzed, and the removal principle is usually considered according to the number of point sets, the gradient change, the data position, etc.
As shown in fig. 7b and 7c, the interference of hole diagonal, which is usually the hole or pattern of the wear plane in the workpiece plane to be detected, will affect the continuity of the laser line, or the laser line point cloud will be distorted, so that the hole diagonal interference points need to be removed. The depth of the holes or the twills in the projection direction of the laser lines is usually larger than that of the abrasion area, the coordinates are usually on the reference line in the point cloud data, the width is limited, the change is violent, the holes or the twills can be identified through the characteristics, and then the holes and the twills interfere with the points to reject the points.
34: and carrying out consistency evaluation on the initial point set by utilizing the loss function.
After the initial point set is obtained, consistency evaluation is carried out on the initial point set by using a loss function, the average Euclidean distance between each point in the initial point set and a bus is calculated, and whether the points in the initial point set pass the consistency evaluation or not is determined according to the average Euclidean distance.
35: and when the initial point set passes the consistency evaluation, taking the initial point set as the consistency point set.
When the average euclidean distance between each point in the initial point set and the bus meets the preset distance, it can be determined that the initial point set passes the consistency evaluation, and the initial point set passing the consistency evaluation is used as a consistency point set.
And circularly eliminating singular points in the consistent points when the average Euclidean distance between the existing points in the initial point set and the bus does not accord with the preset distance until all the points in the initial point set pass through consistency evaluation.
And 104, fitting a reference line f (x, y) for representing the wear area according to the consistency point set.
After the consistency point set is found out, a reference line f (x, y) for representing the abrasion area is calculated by a fitting method. Typically the reference line f (x, y) is a straight line or a quadratic curve. In one case, since the camera shooting angle may be inclined, the reference line f (x, y) may have an included angle with respect to the x-axis, that is, the reference line f (x, y) has a slope k, which may affect the accuracy of determining the wear level such as the wear depth, and therefore, before determining the wear level, the influence of the slope k should be eliminated so that the reference line is substantially parallel to the x-axis.
105: determining a rotation reference line f '(x', y ') such that a slope of the rotation reference line f' (x ', y') with respect to the x-axis is within an interval including 0, according to a slope of the reference line f (x, y) with respect to the x-axis.
A reference line f (x, y) representing the worn area is calculated by the fitting method. The slope of the reference line f (x, y) is k, and the rotation reference line f ' (x ', y ') is determined according to the rotation formula calculated according to the formula 5 from the slope k of the reference line f (x, y) relative to the x-axis:
wherein,
the coordinates of each point in the rotating reference line f ' (x ', y '),
is the coordinate of each point in the reference line f (x, y), k is the slope of the reference line f (x, y) with respect to the x-axis, and θ is the angle of rotation of the reference line f (x, y) with respect to the x-axis.
After the coordinate transformation, the rotation reference line may be simulated by using the transformed coordinate point set, and may be simulated as a quadratic curve or a straight line, which is not limited herein. In the simulated rotation reference line, the slope of any line end is 0 or less than an allowable threshold value, so that the rotation reference line is approximately parallel to the x-axis of the point cloud picture.
The rotating reference line can adopt a quadratic curve generally, is closer to the actual abrasion condition, and meets the application requirement.
As shown in fig. 7a, it is a rotated dot cloud.
106: and determining the abrasion degree of the plane of the workpiece to be measured according to the rotating reference line.
In some embodiments, determining the wear level of the plane of the workpiece to be measured according to the rotation reference line may include:
determining an unworn point in a region where the rotating reference line is located;
and determining the wear depth according to the unworn point and the rotation reference line.
Specifically, as shown in fig. 7a, the worn area generally occupies a relatively large area, and the determining of the unworn point in the area where the rotation reference line is located may include: searching the lowest point of the area lower than the rotation reference line as an unworn point. Then, a wear depth is determined from the unworn point and the rotation reference line.
In some embodiments, determining the wear depth from the unworn point and the rotating reference line may include:
searching from the unworn point to the center of the consistency point set, and taking a point in a preset range of the rotating reference line as a wear point;
and determining the wear depth according to the wear point and the unworn point.
The worn area typically occupies a relatively large area, starting from an unworn point, i.e., a reference line, looking toward the center of the consistency point set, and taking a point near or above the rotating reference line as the worn point.
In some embodiments, determining the wear depth from the wear point and the unworn point may include:
determining at least one of a maximum wear level, an average wear level, or a wear consistency from the unworn point and the wear point.
In some of these embodiments, determining wear consistency comprises:
determining a wear area according to the wear point;
determining the abrasion consistency information according to the curvature of the reference line and the discreteness of the point set corresponding to the abrasion area;
outputting the wear consistency information.
The set of a plurality of wear points can be determined as a wear region, the smaller the curvature of the reference line, the better the consistency, and the smaller the dispersion of the point set, the better the consistency, and the formula 4 can be used to determine the dispersion of the point set.
After the wear consistency information is determined, the wear consistency information is output so that a user can obtain the consistency information.
In some of these embodiments, determining the maximum degree of wear comprises:
acquiring coordinate information of the wear point;
when the ordinate of the abrasion point is the maximum value, determining the abrasion point as the maximum abrasion point;
and outputting the coordinate information corresponding to the maximum abrasion point as maximum abrasion information.
As shown in fig. 8, if the position with the largest ordinate in fig. 8 can be regarded as the maximum wear point, and the corresponding area, then the coordinate information corresponding to the maximum wear point is output, so that the user can obtain the maximum wear point information.
In some of these embodiments, after said determining a wear depth from said unworn point and said rotating reference line, said method further comprises:
and when the wear depth exceeds the preset wear degree, outputting prompt information for prompting a user to replace the workpiece to be detected.
Can set for one and predetermine the degree of wear, when exceeding when predetermineeing the degree of wear, explain this work piece wearing and tearing too much, be not convenient for continue to use, the suggestion user of output should be changed and the suggestion information of waiting to examine the work piece.
The embodiment of the invention adopts a laser measurement technology, carries out plane abrasion measurement by an intelligent method, adopts a local searching mode, determines a consistency point set positioned in an abrasion area in point cloud data, and fits a reference line for representing the abrasion area according to the consistency point set, thereby effectively and accurately obtaining the reference line; determining a rotating reference line according to the slope of the reference line relative to the x axis, so that the slope of the rotating reference line relative to the x axis is within an interval containing 0, and effectively and accurately rotating the reference line; according to the rotating reference line, the abrasion degree of the plane of the workpiece to be measured is determined, so that the measurement precision is greatly improved, and the measurement requirements of most scenes can be met.
Fig. 9 is a schematic diagram of a hardware structure of a controller in an embodiment of the system 10 for measuring the plane wear of a workpiece, and as shown in fig. 9, the controller 13 includes:
one or more processors 131, memory 132. Fig. 9 illustrates an example of one processor 131 and one memory 132.
The processor 131 and the memory 132 may be connected by a bus or other means, and fig. 9 illustrates the connection by the bus as an example.
The memory 132, which is a non-volatile computer-readable storage medium, may be used for storing non-volatile software programs, non-volatile computer-executable programs, and modules, such as program instructions/modules corresponding to the method for measuring the plane wear of a workpiece in the embodiments of the present application. The processor 131 executes various functional applications of the controller and data processing, namely, the method for measuring the plane wear of the workpiece, which implements the above-described method embodiments, by executing the nonvolatile software programs, instructions and modules stored in the memory 132.
The memory 132 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the storage data area may store data created from use of a measurement system of the workpiece plane wear, and the like. Further, the memory 132 may include high speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid state storage device. In some embodiments, memory 132 optionally includes memory remotely located from processor 131, and these remote memories may be connected to a workpiece plane wear measurement system via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The one or more modules are stored in the memory 132 and, when executed by the one or more processors 131, perform the method for measuring workpiece plane wear in any of the method embodiments described above, e.g., performing the method steps 101-106 of fig. 2 described above.
The product can execute the method provided by the embodiment of the application, and has corresponding functional modules and beneficial effects of the execution method. For technical details that are not described in detail in this embodiment, reference may be made to the methods provided in the embodiments of the present application.
Embodiments of the present application provide a non-transitory computer-readable storage medium storing computer-executable instructions, which are executed by one or more processors, such as the processor 131 in fig. 9, to enable the one or more processors to perform the method for measuring the plane wear of the workpiece in any of the method embodiments, such as the method steps 101 to 106 in fig. 2.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
Through the above description of the embodiments, those skilled in the art will clearly understand that the embodiments may be implemented by software plus a general hardware platform, and may also be implemented by hardware. It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware related to instructions of a computer program, which can be stored in a computer readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (14)
1. A method of measuring wear of a planar surface of a workpiece, the method comprising:
projecting a laser line to a plane of a workpiece to be detected, and acquiring an image containing the laser line;
acquiring point cloud data related to the laser line according to the image; the point cloud data is a coordinate data sequence D of the laser line projected on the plane of the workpiece to be detectedn(ii) a Wherein D isn＝{d1(x1,y1)……dn(xn,yn) N is a positive integer, dn(xn,yn) Representing the laser spot d on said laser linenCoordinates, x, projected on the plane of the workpiece to be inspectednIndicating the laser spot d with the length direction of the laser line as the x-axisnCorresponding x-axis coordinate, ynIndicating a laser point d when the depth direction of the laser line on the plane of the workpiece to be detected is taken as a y-axisnCorresponding y-axis coordinates;
determining a set of consistency points DS located in a wear region in the point cloud datan(ii) a Wherein, DSnIs DnA subset of (a);
fitting a reference line f (x, y) for representing a wear area according to the consistency point set;
determining a rotation reference line f '(x', y ') such that the slope of the rotation reference line f' (x ', y') with respect to the x-axis is within an interval including 0, from the slope of the reference line f (x, y) with respect to the x-axis;
determining the abrasion degree of the plane of the workpiece to be detected according to the rotating reference line;
wherein the determining a consistent set of points located in a wear region in the point cloud data comprises:
searching continuous sections with loss functions smaller than a preset value and in accordance with a preset length in the point cloud data as a bus;
extending a consistency point according to the bus;
eliminating singular points in the consistency points to obtain an initial point set;
performing consistency evaluation on the initial point set by using the loss function;
and when the initial point set passes the consistency evaluation, taking the initial point set as the consistency point set.
2. The method of claim 1, wherein the determining the rotation reference line is calculated according to a rotation formula, the rotation formula being:
wherein,
the coordinates of each point in the rotating reference line f ' (x ', y '),
is the coordinate of each point in the reference line f (x, y), k is the slope of the reference line f (x, y) with respect to the x-axis, and θ is the angle of rotation of the reference line f (x, y) with respect to the x-axis.
3. The method of claim 1, wherein said determining the degree of wear of the workpiece plane to be inspected from the rotating reference line comprises:
determining an unworn point in the area where the rotating reference line is located;
and determining the wear depth according to the unworn point and the rotation reference line.
4. The method of claim 3, wherein said determining an unworn point in a region where said rotating reference line is located comprises:
searching the lowest point of the area lower than the rotation reference line as an unworn point.
5. The method of claim 3, wherein said determining a wear depth from said unworn point and said rotating reference line comprises:
searching from the unworn point to the center of the consistency point set, and taking a point in a preset range of the rotating reference line as a wear point;
and determining the wear depth according to the wear point and the unworn point.
6. The method of claim 5, wherein determining a wear depth from the wear point and the unworn point comprises:
determining at least one wear level of a maximum wear level, an average wear level, and a wear consistency from the unworn point and the wear point.
7. The method of claim 6, wherein said determining a wear consistency comprises:
determining a wear area according to the wear point;
determining the abrasion consistency information according to the curvature of the reference line and the discreteness of the point set corresponding to the abrasion area;
outputting the wear consistency information.
8. The method of any one of claims 6 or 7, wherein said determining a maximum degree of wear comprises:
acquiring coordinate information of the wear point;
when the ordinate of the abrasion point is the maximum value, determining the abrasion point as the maximum abrasion point;
and outputting the coordinate information corresponding to the maximum abrasion point as maximum abrasion information.
9. The method of claim 3, wherein after said determining a wear depth from said unworn point and said rotating reference line, said method further comprises:
and when the wear depth exceeds a preset wear degree, outputting prompt information for prompting a user to replace the workpiece to be detected.
10. The method of claim 1, wherein the step of finding continuous segments with loss functions smaller than a preset value and conforming to a preset length in the point cloud data as a bus comprises:
and in the point cloud data, searching continuous sections with loss functions smaller than a preset value and in accordance with a preset length from the center of the point cloud data to two ends or from two ends of the point cloud data to the center as a bus.
11. The method of claim 1, wherein said augmenting a consistency point according to the bus bar comprises:
calculating the Euclidean distance from a point in the preset range of the bus to the bus in the preset range of the bus;
and if the Euclidean distance is smaller than the preset distance, combining the corresponding point with the bus to obtain a consistency point.
12. The method according to claim 1, wherein the removing singular points from the consistency points to obtain an initial point set comprises:
and eliminating at least one singular point comprising a discrete point and a hole twill interference point in the consistency points to obtain the initial point set.
13. A system for measuring the planar wear of a workpiece, the system comprising:
a support;
the laser is fixed on the bracket and projects laser lines to the plane of the workpiece to be detected;
the camera is fixed on the bracket and used for acquiring an image containing the laser line;
at least one processor, and
a memory communicatively coupled to the at least one processor, the memory storing instructions executable by the at least one processor to enable the at least one processor to perform the method of any of claims 1-12.
14. A non-transitory computer-readable storage medium having stored thereon computer-executable instructions that, when executed by a workpiece plane wear measurement system, cause the workpiece plane wear measurement system to perform the method of any of claims 1-12.
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| CN202011287507.1A CN112284256B (en) | 2020-11-17 | 2020-11-17 | Method and system for measuring plane abrasion of workpiece |
| PCT/CN2021/130178 WO2022105676A1 (en) | 2020-11-17 | 2021-11-12 | Method and system for measuring wear of workpiece plane |
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| CN112284256B (en) * | 2020-11-17 | 2022-06-10 | 深圳市道通科技股份有限公司 | Method and system for measuring plane abrasion of workpiece |
| CN113096067B (en) * | 2021-03-04 | 2022-10-11 | 深圳市道通科技股份有限公司 | Method and system for determining surface wear of workpiece |
| CN114383502A (en) * | 2021-12-29 | 2022-04-22 | 国能铁路装备有限责任公司 | Method and device for measuring wear amount of fittings of bogie and measuring equipment |
| CN115090842B (en) * | 2022-06-06 | 2024-06-07 | 首钢京唐钢铁联合有限责任公司 | Continuous casting machine base positioning method and related equipment |
| CN116703892B (en) * | 2023-08-01 | 2023-11-14 | 东莞市京品精密模具有限公司 | Image data-based lithium battery cutter abrasion evaluation and early warning method |
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