A method for detecting three-dimensional dimensions of core blocks based on neighborhood screening

Abstract

The present application provides a method for detecting the three-dimensional size of a core block based on neighborhood screening, which relates to the field of core block measurement technology. The method comprises: performing line and surface analysis on the core block according to the processing size of the rotating body, obtaining various geometric elements of the rotating body core block and their geometric spatial relationships; constructing a corresponding geometric structure mathematical relationship model according to the various geometric elements and their geometric spatial relationships, and determining the target tolerance bands corresponding to the cross-sectional circles at the intersection of the geometric elements and the bottom circles of the conical surface geometric elements in the model; constructing a standard tolerance model according to the target tolerance band and the model; collecting point cloud data of the target rotating body core block obtained by processing to construct a three-dimensional model; performing tolerance neighborhood screening on the point cloud data in the three-dimensional model according to the standard tolerance model to obtain the target three-dimensional model; and determining the actual measurement values ​​of each size to be detected according to the target three-dimensional model. The method aims to improve the efficiency and stability of the size detection of nuclear fuel core blocks.

Description

Technical Field

[0001] The present application relates to the technical field of core block measurement, and in particular to a method for detecting three-dimensional dimensions of core blocks based on neighborhood screening. Background Art

[0002] Nuclear energy, as a clean, low-carbon, safe, and efficient non-fossil energy, is an important choice for green development. Nuclear power design adopts the principle of defense in depth, with nuclear fuel cores as the first line of defense, and parameter control is the core of nuclear power development safety.

[0003] In the process of general part parameter detection, data collection methods are divided into two categories: contact and non-contact. Among them, in actual production, nuclear fuel core block detection generally adopts contact method. Although its technology is mature, reliable and the detection equipment is low-priced, it has problems such as deformation of its contact surface, limited measurement range and inconvenient maintenance. In addition, non-contact 3D laser scanning technology realizes large-area, high-resolution surface morphology measurement of 3D objects through high-speed laser scanning. Due to its fast, non-contact and high-precision characteristics, it is widely used in the field of industrial online measurement. However, this non-contact measurement method requires a large amount of data to be calculated and processed, and the measurement efficiency is low. Summary of the invention

[0004] In view of this, the present application provides a three-dimensional pellet size detection method based on neighborhood screening, aiming to improve the efficiency and stability of nuclear fuel pellet size detection.

[0005] In a first aspect of an embodiment of the present application, a method for detecting three-dimensional size of a core block based on neighborhood screening is provided, the method comprising:

[0006] According to the processing size of the rotating body core block, the geometric elements and geometric space relationship of the rotating body core block are analyzed by line and surface to obtain various geometric elements of the rotating body core block and the geometric space relationship between various geometric elements of the rotating body core block, wherein the various geometric elements include spherical geometric elements, plane geometric elements and conical geometric elements;

[0007] According to various geometric elements of the rotating body core block and the geometric spatial relationship between the various geometric elements, a geometric structure mathematical relationship model corresponding to the rotating body core block is constructed;

[0008] Determine the target tolerance zones corresponding to the cross-sectional circles at the intersections of the geometric elements in the geometric structure mathematical relationship model, the bottom circles of the conical geometric elements, and the lowest points of the spherical geometric elements;

[0009] Constructing a standard tolerance model of the rotating body core block according to the target tolerance zone and the geometric structure mathematical relationship model;

[0010] Performing point cloud data collection on the target rotating body core block obtained by machining to construct a three-dimensional model of the target rotating body core block;

[0011] According to the standard tolerance model, performing tolerance neighborhood screening on the point cloud data in the three-dimensional model to obtain a target three-dimensional model;

[0012] According to the target three-dimensional model, the actual measurement value of each size to be detected is determined, wherein the size to be detected includes the disc diameter size, disc depth size, shoulder width size, chamfer height size and chamfer width size where the geometric elements intersect.

[0013] Optionally, determining the target tolerance zones corresponding to the cross-sectional circles at the intersections of the geometric elements in the geometric structure mathematical relationship model, the bottom circles of the conical surface geometric elements, and the lowest points of the spherical surface geometric elements, respectively, comprises:

[0014] Determine the radius of the cross-section circle and the radius of the base circle of the conical surface geometric element in the geometric structure mathematical relationship model;

[0015] According to the radius of the cross-section circle, the radius of the bottom circle and the preset tolerance zone mapping relationship, determine the tolerance zone corresponding to the radius of the cross-section circle in the preset tolerance zone mapping relationship, and determine the tolerance zone corresponding to the radius of the bottom circle;

[0016] Determine the tolerance zone corresponding to the radius of the cross-sectional circle as the target tolerance zone corresponding to the cross-sectional circle, and determine the tolerance zone corresponding to the bottom surface circle as the target tolerance zone corresponding to the bottom surface circle;

[0017] The tolerance zone corresponding to the point element in the preset tolerance zone mapping relationship is obtained and determined, and the tolerance zone is determined as the target tolerance zone corresponding to the lowest point of the spherical geometric element.

[0018] Optionally, collecting point cloud data of the target rotating body core block obtained by machining to construct a three-dimensional model of the target rotating body core block includes:

[0019] Rotating the core block of the target rotating body at an angle parallel to the horizontal plane to perform multi-angle parallel projection to obtain corresponding multiple projection planes;

[0020] Determining the rotation center axis of the target rotating body core block according to the plurality of projection planes;

[0021] Scanning the target rotating body core block in a direction perpendicular to the rotation center axis by a scanning device to obtain a corresponding point cloud data set;

[0022] Based on the point cloud data set, a three-dimensional model of the target rotating body core block is constructed.

[0023] Optionally, performing tolerance neighborhood screening on the point cloud data in the three-dimensional model according to the standard tolerance model to obtain a target three-dimensional model includes:

[0024] Performing denoising processing on the three-dimensional model to obtain a denoised three-dimensional model;

[0025] According to the denoised three-dimensional model, determining a reference axis in the denoised three-dimensional model, wherein the reference axis is an axis passing through the coordinates of the center of a spherical geometric element in the denoised three-dimensional model and passing through the lowest point of the spherical geometric element;

[0026] According to the target tolerance zone in the standard tolerance model and the reference axis, screening the point cloud data set within the target tolerance zone in the denoised three-dimensional model;

[0027] Construct the target 3D model based on the filtered point cloud dataset.

[0028] Optionally, determining a reference axis in the denoised three-dimensional model according to the denoised three-dimensional model includes:

[0029] Acquire point cloud data related to spherical geometric elements in the denoised three-dimensional model;

[0030] Performing spherical fitting on the point cloud data related to the spherical geometric elements to determine the spherical center coordinates and spherical radius of the spherical geometric elements in the denoised three-dimensional model;

[0031] According to the spherical center coordinates, a reference axis in the denoised three-dimensional model is determined.

[0032] Optionally, screening a point cloud data set within the target tolerance zone in the denoised three-dimensional model according to the target tolerance zone in the standard tolerance model and the reference axis includes:

[0033] According to the first range formula of the target tolerance zone corresponding to the reference axis and the first section circle on the two-dimensional coordinate plane , filter the point cloud data that meets the first range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance zone corresponding to the first section circle, where (p1, p2) represents the center coordinates of the first section circle on the two-dimensional coordinate plane, and ra represents the range of increasing and decreasing the corresponding target tolerance zone by half on the standard radius of the first section circle;

[0034] According to the second range formula of the target tolerance zone corresponding to the reference axis and the second section circle on the two-dimensional coordinate plane , filter the point cloud data that meets the second range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance zone corresponding to the second section circle, where (p1, p2) represents the center coordinates of the second section circle on the two-dimensional coordinate plane, and rb represents the range of increasing and decreasing the corresponding target tolerance zone by half on the standard radius of the second section circle;

[0035] According to the third range formula of the base circle of the reference axis and the conical surface geometric element on the two-dimensional coordinate plane , filter the point cloud data that meets the third range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance band corresponding to the bottom circle, where (p1, p2) represents the center coordinates of the bottom circle on the two-dimensional coordinate plane, and rc represents the range of increasing and decreasing the corresponding target tolerance band by half on the standard radius of the bottom circle.

[0036] Optionally, determining actual measurement values ​​of respective dimensions to be detected according to the target three-dimensional model includes:

[0037] When the size to be detected is a dish diameter size, the point cloud data set within the target tolerance band corresponding to the first section circle is fitted by the least squares circle fitting formula to obtain the actual measurement value of the radius of the first section circle in the target three-dimensional model;

[0038] Determine the actual measured value of the radius of the first cross-section circle in the target three-dimensional model as the actual measured value of the disk diameter size corresponding to the target three-dimensional model;

[0039] In the case where the size to be detected is a dish depth size, the actual measurement value of the dish depth size is obtained by bringing the actual measurement value of the radius of the first cross-section circle in the target three-dimensional model and the actual measurement value of the spherical radius of the spherical geometric element in the target three-dimensional model into the dish depth algorithm for calculation, and the actual measurement value of the spherical radius is synchronously determined in the process of performing spherical fitting on the point cloud data related to the spherical geometric element and determining the spherical center coordinates of the spherical geometric element in the denoised three-dimensional model;

[0040] When the dimension to be detected is the shoulder width dimension, the point cloud data set within the target tolerance band corresponding to the second section circle is fitted by the least squares circle fitting formula to obtain the actual measurement value of the radius of the second section circle in the target three-dimensional model;

[0041] Subtracting the calculated actual measurement value of the radius of the first cross-section circle in the target three-dimensional model from the calculated actual measurement value of the radius of the second cross-section circle in the target three-dimensional model to obtain the actual measurement value of the shoulder width;

[0042] When the dimension to be detected is the chamfer width dimension, the point cloud data set within the target tolerance band corresponding to the bottom circle is fitted by the least squares circle fitting formula to obtain the actual measured value of the radius of the bottom circle in the target three-dimensional model and the axial average value of the bottom circle perpendicular to the plane geometric elements;

[0043] Subtracting the calculated actual measurement value of the radius of the second cross-section circle in the target three-dimensional model from the actual measurement value of the radius of the bottom circle in the target three-dimensional model to obtain the actual measurement value of the chamfer width;

[0044] When the dimension to be detected is the chamfer height dimension, the axial value perpendicular to the plane geometric element is subtracted from the axial average value perpendicular to the plane geometric element in the bottom circle to obtain the chamfer height dimension.

[0045] Optionally, the method further includes:

[0046] Determine the deviation between the actual measured value of the to-be-detected dimension of the target rotating body core block and the standard value of the to-be-detected dimension;

[0047] A machining result of the target rotating body core block is determined according to the standard tolerance model and the deviation.

[0048] Optionally, determining the standard value of each dimension to be detected in the geometric structure mathematical relationship model includes:

[0049] When the size to be detected is a disk-shaped diameter size, the radius of a first cross-sectional circle generated by the intersection of the spherical geometric element and the plane geometric element is calculated, and the radius of the first cross-sectional circle is determined to be a standard value of the disk-shaped diameter size;

[0050] When the size to be detected is a dish-shaped depth size, the spherical radius of the spherical geometric element is obtained by fitting the spherical geometric element through the spherical equation; the standard value of the dish-shaped depth size is obtained by bringing the spherical radius and the radius of the first cross-sectional circle into the dish-shaped depth algorithm for calculation. The expression of the dish-shaped depth algorithm is: , where dt1 is the value of the dish depth, r1 is the spherical radius, and Sr1 is the radius of the first section circle;

[0051] When the dimension to be detected is the shoulder width dimension, the standard value of the radius of the second cross-section circle generated by the intersection of the conical surface geometric element and the plane geometric element is calculated; the standard value of the radius of the first cross-section circle obtained by calculation is subtracted from the standard value of the radius of the second cross-section circle to obtain the standard value of the shoulder width dimension;

[0052] When the dimension to be detected is the chamfer width dimension, the standard value of the radius of the bottom circle of the conical surface is obtained by fitting the geometric elements of the conical surface; the standard value of the radius of the bottom circle is subtracted from the standard value of the radius of the second cross-section circle to obtain the standard value of the chamfer width dimension;

[0053] When the dimension to be detected is the chamfer height dimension, the distance between the bottom surface of the conical surface geometric element and the plane geometric element is determined as the standard value of the chamfer height dimension.

[0054] Optionally, determining the machining result of the target rotating body core block according to the standard tolerance model and the deviation includes:

[0055] When the deviations of all the dimensions to be detected are within the corresponding target tolerance bands, determining that the machining result of the target rotating body core block is qualified;

[0056] In the case that the deviation of the dimension to be detected is larger than the target tolerance range, the machining result of the target rotating body core block is determined to be unqualified.

[0057] Compared with the prior art, this application has the following advantages:

[0058] The embodiment of the present application provides a method for detecting the three-dimensional size of a core block based on neighborhood screening. First, according to the processing size of the rotating core block, the geometric elements and geometric spatial relationships of the rotating core block are analyzed by line and surface to obtain various geometric elements of the rotating core block and the geometric spatial relationships between various geometric elements of the rotating core block. Various geometric elements include spherical geometric elements, plane geometric elements and conical surface geometric elements; according to various geometric elements of the rotating core block and the geometric spatial relationships between various geometric elements, a geometric structure mathematical relationship model generated by the intersection of various geometric elements under the geometric spatial relationship is determined; the intersection of geometric elements in the geometric structure mathematical relationship model is determined. The target tolerance zone corresponding to the cross-sectional circle; constructing a standard tolerance model of the rotating body core block according to the target tolerance zone and the mathematical relationship model of the geometric structure; collecting point cloud data of the target rotating body core block obtained by processing, and constructing a three-dimensional model of the target rotating body core block; according to the standard tolerance model, performing tolerance neighborhood screening on the point cloud data in the three-dimensional model to obtain the target three-dimensional model; according to the target three-dimensional model, determining the actual measurement value of each dimension to be detected, wherein the dimensions to be detected include the dish diameter dimension, dish depth dimension, shoulder width dimension, chamfer height dimension and chamfer width dimension where the geometric elements intersect. Therefore, in the process of detecting rotating nuclear fuel core blocks, the present application first constructs a geometric structure mathematical model relationship model through line and surface analysis of geometric elements and geometric space relationships, and then constructs a standard tolerance model of the rotating nuclear fuel core blocks by introducing tolerance bands. Then, the standard tolerance model is used to perform neighborhood screening on the three-dimensional model composed of all point cloud data scanned and collected for the target rotating core blocks obtained by actual processing, and the rotating core blocks are detected in the screened point cloud data to determine the actual measured values ​​of each dimension to be detected of the target rotating core blocks obtained by actual processing. This greatly reduces the regional range of data points in the size calculation and simplifies the amount of data that needs to be processed and calculated. At the same time, the process utilizes the analysis results of geometric elements and can also be more conveniently and efficiently applied to the calculation of size data of three-dimensional point cloud data.

[0059] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0061] Figure 1 A flowchart of a method for detecting three-dimensional size of a core block based on neighborhood screening provided in an embodiment of the present application;

[0062] Figure 2 A schematic diagram of a rotating body core block to which a core block three-dimensional size detection method based on neighborhood screening provided in an embodiment of the present application is applied;

[0063] Figure 3 A schematic diagram of geometric elements of a rotating core block in a core block three-dimensional size detection method based on neighborhood screening provided in an embodiment of the present application;

[0064] Figure 4 A schematic cross-sectional view of spherical geometric elements in a method for detecting three-dimensional dimensions of a core block based on neighborhood screening provided in an embodiment of the present application;

[0065] Figure 5 A schematic diagram of a cross-sectional circle and a size to be detected in a method for detecting three-dimensional size of a core block based on neighborhood screening provided in an embodiment of the present application;

[0066] Figure 6 A schematic diagram of a target tolerance zone in a core block three-dimensional size detection method based on neighborhood screening provided in an embodiment of the present application;

[0067] Figure 7 A schematic diagram of a point cloud after tolerance neighborhood screening in a core block three-dimensional size detection method based on neighborhood screening provided in an embodiment of the present application;

[0068] Figure 8 A schematic diagram of the size to be detected in a method for detecting three-dimensional size of a core block based on neighborhood screening provided in an embodiment of the present application;

[0069] Fig. 9 A schematic diagram of the point cloud data set fitting in a core block three-dimensional size detection method based on neighborhood screening provided in an embodiment of the present application. DETAILED DESCRIPTION

[0070] Exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings.

[0071] Figure 1 A flowchart of a method for detecting three-dimensional size of a core block based on neighborhood screening is provided in an embodiment of the present application, as shown in FIG. Figure 1 As shown, the method includes:

[0072] Step S1: According to the processing size of the rotating body core block, line and surface analysis is performed on the geometric elements and geometric spatial relationships of the rotating body core block to obtain various geometric elements of the rotating body core block and the geometric spatial relationships between the various geometric elements of the rotating body core block, wherein the various geometric elements include spherical geometric elements, plane geometric elements and conical surface geometric elements.

[0073] In this embodiment, the method for detecting the three-dimensional size of a core block based on neighborhood screening provided by the present application can be applied to rotating structures composed of different lines and surfaces, and is not limited to the number of line and surface components and the type of surface structure. The three-dimensional point cloud data can be processed by using geometric element analysis and neighborhood screening. The present application is mainly applied to rotating core blocks of nuclear fuel in mechanical parts, such as Figure 2 As shown in the figure, the main body of the rotating core block is a cylinder, and both ends of the cylinder are composed of a conical surface, a spherical surface of the concave part and a plane perpendicular to the central axis of the cone. For ease of understanding, only one end of the composition diagram is shown. The nuclear fuel rotating core block includes various geometric elements such as planes, spherical surfaces and conical surfaces, such as Figure 3 As shown. Figure 2 The geometric elements shown intersect each other, and the resulting components are two intersecting contour lines of space cross-section circles with different radii (such as Figure 2 The cross-sectional circles 1 and 2 in the figure are shown in FIG. 1 ), and the dimensions to be tested at this time are the dish depth, dish diameter, shoulder width, chamfer height and chamfer width of the rotating body core block.

[0074] In this embodiment, when the processing size of the rotating body core block is known, the standard values ​​of each size to be detected of the rotating body core block under theoretical conditions can be obtained. On this basis, the rotating body core block is subjected to line and surface analysis. According to the four steps of separation, extraction, fitting, and derivation, the geometric element characteristics and the spatial relationship of the geometric elements of the rotating body core block are analyzed to obtain various geometric elements constituting the rotating body core block and the spatial relationship between the various geometric elements. Among them, the various geometric elements constituting the rotating body core block include at least spherical geometric elements, plane geometric elements, and conical surface geometric elements.

[0075] For example, Figure 2 As shown, Figure 2 A three-dimensional schematic diagram of a rotating core block is shown, in which Figure 2 Take the rotating body core block shown as an example for explanation, based on the xyz coordinate system, the z axis is collinear with the common reference axis, and when the processing dimensions of the rotating body core block are known, the standard values ​​of the various dimensions to be detected of the rotating body core block under theoretical conditions can be obtained, and the various dimensions to be detected include the dish depth dt1, dish diameter Sd1, shoulder width w, chamfer width Cw and chamfer height Ch. On this basis, the rotating body core block is subjected to line and surface analysis, and according to the four steps of separation, extraction, fitting and derivation, the geometric element characteristics and spatial relationship of the rotating body core block are analyzed to obtain the plane geometric elements, conical surface geometric elements and spherical surface geometric elements that constitute the rotating body core block, as well as the spatial relationship between these types of geometric elements. Figure 3 As shown, Figure 3The plane geometric elements, cone geometric elements and spherical geometric elements are obtained by separating the core block of the rotating body, among which, the center of the sphere is set as O1, and a center line passing through the center of the sphere O1 on the sphere is L1; a point on the plane is set as O2, and a normal line passing through O2 on the plane and perpendicular to the plane is L2; ​​the center of the base circle of the cone is set as O3, and a center line of the rotation axis on the cone surface passing through the center O3 and perpendicular to the base circle is L3.

[0076] According to the coordinates of the center O1 of the sphere (a1, b1, c1), the radius of the sphere is r1, the coordinates of a point O2 on the plane are (a2, b2, c2), the coordinates of the normal vector are (A, B, C), the coordinates of the center O3 of the base of the cone are (a3, b3, c3), the radius of the base circle is r3, and the height of the cone is h3, it can be determined that the ideal geometric model corresponding to each type of geometric element is expressed as:

[0077] , where the center line L1 of the spherical geometric element is , the perpendicular line L2 of the plane geometric element is , the center line L3 of the rotation axis of the conical surface geometric element is After completing the analysis of the geometric elements and geometric space relationship of the rotating body core block, find and determine the reference point or reference line of the overall structure. In this embodiment, the center lines L1 and L3 derived from the spherical geometric elements and the conical geometric elements are collinear with the normal line L2 of the plane geometric elements, thereby determining that the center of the generated cross-section circle 1 is on the center line L1 and the center of the cross-section circle 2 is on the center line L3, and are collinear with the normal line L2 of the plane geometric elements, that is, Based on this, it can be concluded that the overall geometric structure of the rotating core block is developed around the same center line, and points O1, O2, and O3 are also on the same center line, that is, all the separated components are at the same geometric center, and there is a unique common reference line L, and .

[0078] Step S2: constructing a geometric structure mathematical relationship model corresponding to the rotating body core block according to various geometric elements of the rotating body core block and the geometric spatial relationship between the various geometric elements.

[0079] In this embodiment, the component line can be generated by the intersection of two surfaces, wherein a space cross-section circle (such as Figure 2 In addition, when a plane geometric element intersects with a conical surface geometric element, and the plane geometric element is parallel to the bottom surface of the conical surface geometric element, another space cross-sectional circle is generated at the intersection of the two (such as Figure 2The center lines of the spherical geometric elements and the conical geometric elements coincide with each other, and the intersection line generated by the direct intersection is not displayed. This intersection line has no practical significance in the geometric structure of the core block of the rotating body. Therefore, the space cross-sectional circle generated by the intersection of the above-mentioned plane geometric elements and the spherical geometric elements and the other space cross-sectional circle generated by the intersection of the plane geometric elements and the conical geometric elements are concentric circles.

[0080] After completing the line and surface analysis, the geometric structure of the rotating body core block is converted into the required size parameters to be tested. Among them, the distance from the vertical lowest point of the intersection area of ​​the plane geometric element and the spherical geometric element to the plane is the dish depth dt1; the cross-sectional circle generated by the intersection of the plane geometric element and the spherical geometric element is the dish diameter Sd1, and the difference in radius between the two cross-sectional circles generated by the intersection of the plane geometric element with the spherical geometric element and the conical geometric element is the shoulder width w.

[0081] After obtaining the geometric structure of the rotating body core block and the corresponding mathematical model of the reference line, the calculation of the disc diameter Sd1 to be detected is converted into the calculation of the radius Sr1 of the cross-sectional circle generated by the intersection of the plane geometric element and the spherical geometric element; the calculation of the shoulder width w to be detected is converted into the difference between the radius Sr2 of the cross-sectional circle generated by the intersection of the plane geometric element and the conical surface geometric element and the radius Sr1 of the cross-sectional circle generated by the intersection of the plane geometric element and the spherical surface geometric element; the calculation of the disc depth dt1 to be detected is converted into the spherical equation fitting of the spherical geometric element to obtain the lowest point Q, and the vertical distance dt2 from the center of the sphere to the cross-sectional circle generated by the intersection of the plane geometric element and the spherical surface geometric element; the calculation of the chamfer width Cw to be detected is converted into the calculation of the radius r3 of the bottom circle of the conical surface geometric element; the calculation of the chamfer height Ch to be detected is converted into the radius of the bottom circle of the conical surface geometric element and the axial average value of the bottom circle perpendicular to the plane geometric element.

[0082] like Figure 4 As shown, it is a schematic diagram of the spherical cross section of the spherical geometric element in the core block of the rotating body in this embodiment. Based on the xz coordinate system, the corresponding geometric shape parameters are obtained in the overall structure, where circle O is the vertical cross section circle of the spherical geometric element through the center of the sphere (same as the center of the spherical geometric element O1), straight line MN is a plane, area MNQ is a disc-shaped area, and point H is the foot of the perpendicular between OQ and MN. In addition, the common reference line L coincides with OQ, that is, the center line L1 of the sphere, the plane normal L2, and the center line L3 of the cone are the same as OQ.

[0083] In an ideal situation, we can know the disc depth dt1 and disc radius Sr1 of the rotating body core block, and Sd1=2*Sr1. We can then find the radius r1 of the spherical geometric element and the distance dt2 from the center of the sphere to the plane geometric element. Establish the mathematical equations of r1, dt2 and dt1, Sr1

[0084] , and eliminate r1 to obtain the equation

[0085] Based on this equation, we can get the equation for the distance dt2 from the center of the sphere to the plane geometric element:

[0086] , substituting into r1, we get the equation

[0087] , setting the coordinates of point Q to (x0, y0, z0), we can get the coordinates of the center O of the sphere corresponding to the dish depth dt1 and the dish radius Sr1. The distance r1 moved along the positive direction of the z axis by point Q is expressed as (x0, y0, z0+r1), that is,

[0088] , the spherical equation is

[0089] , where (x, y, z) are the three-dimensional coordinates on the sphere and satisfy

[0090] The spherical equation can be determined by a point Q, a dish depth dt1, and a dish radius Sr1.

[0091] Assume that point O2 in the plane equation coincides with point H, and point H (x0, y0, z0 + dt1) is point Q moved along the positive direction of the z axis by a distance dt1. Then the plane normal L2 coincides with the center line OQ. Under the known theoretical conditions, point Q and the dish depth dt1, and the plane is perpendicular to the z axis, the plane equation is simplified to

[0092] , where (x, y, z) are the three-dimensional coordinates on the plane, there exists

[0093] , the planes in the geometric elements intersect each other to generate lines. In this embodiment, the plane geometric elements intersect with the spherical geometric elements and the conical geometric elements to generate cross-sectional circles 1 and 2, which are concentric circles. When the equation of cross-sectional circle 1 is obtained, the equation of cross-sectional circle 2 can also be obtained at the same time. It is known that the disk diameter in cross-sectional circle 1 is Sd1, and the diameter Sd2 in cross-sectional circle 2 can be obtained as the sum of the disk diameter and the shoulder width, that is, Sd2=Sd1+2*w.

[0094] like Figure 5 As shown in the schematic diagram of the cross-section circle and the detection size in this embodiment, based on the xy coordinate system, the cross-section circle 1 is on the plane geometric element, its height z-axis information is the same as the plane, and its center is Figure 4 The midpoints H coincide, so the parametric equation of the cross-section circle 1 is

[0095] , where (a4,b4,c4) is the center of the cross-section circle.

[0096] Substituting the center H and the radius Sr1 of the cross-section circle 1, we can get

[0097] , where (x, y, z) are the three-dimensional coordinates on the cross-section circle, then

[0098] , based on the same calculation method, the parametric equation of section circle 2 is

[0099] , where (x, y, z) are the three-dimensional coordinates on the cross-section circle.

[0100] Then the only common reference line L is a straight line passing through point Q and perpendicular to the xy plane. The direction vector of the reference line L is the same as the direction vector of the z-axis, which is (0,0,1). Then the equation of the straight line function is

[0101] , where (a5, b5, c5) is a point on the line, d5 is a non-zero real number, and substituting point Q, we get

[0102] , that is

[0103] .

[0104] The calculation of the chamfer width Cw, the dimension to be measured, is converted into the calculation of the radius r3 of the bottom circle of the conical surface geometric element. That is, r3 can be obtained by circle fitting, and the chamfer width Cw is obtained by subtracting the radius of the bottom circle of the conical surface from the radius Sr2 of the cross-section circle 2. The corresponding xy coordinates of the bottom circle of the conical surface satisfy the equation

[0105] .

[0106] The chamfer height Ch calculation is converted into the size to be detected calculation into the base circle radius of the conical surface geometric element and the average value of the z coordinate of the point cloud data of the base circle.

[0107] At this point, the basic geometric element equations of the rotating body core block under ideal conditions can be obtained, and the calculation of the dimensions to be detected, such as the dish depth dt1, dish diameter Sd1, shoulder width w, chamfer width Cw and chamfer height Ch in the rotating body core block can be converted into a geometric mathematical model. After determining a fixed and special reference point or reference line, the geometric structure of the rotating body core block can be completely converted into a geometric model to achieve reconstruction of the geometric spatial relationship, thereby obtaining the geometric structure mathematical relationship model of the rotating body core block.

[0108] Step S3: determining the target tolerance zones corresponding to the cross-sectional circles at the intersections of the geometric elements in the geometric structure mathematical relationship model, the bottom circles of the conical geometric elements, and the lowest points of the spherical geometric elements.

[0109] In this embodiment, for the dish depth dt1, dish diameter Sd1, shoulder width w, chamfer width Cw and chamfer height Ch to be detected, the rotating body core block is converted into the dimensions of the lowest point Q, cross-section circle 1, cross-section circle 2 and the bottom circle of the conical surface after being geometrically transformed into the dimensions of the lowest point Q, cross-section circle 1, cross-section circle 2 and the bottom circle of the conical surface in the spherical region. Therefore, after the geometric structure mathematical relationship model of the rotating body core block is obtained through reconstruction in step S2, the present application determines the cross-section circle ( Figure 2 The target tolerance zone of the cross-sectional circle 1) in the geometric structure is determined, and the cross-sectional circle ( Figure 2 The target tolerance zone of the cross-sectional circle 2) in the cone surface is determined, and the bottom circle of the conical surface geometric feature ( Figure 2 The target tolerance zone of the bottom circle in the figure is determined, and the target tolerance zone of the lowest point of the spherical geometric element is determined at the same time.

[0110] In this embodiment, after the geometric structure mathematical relationship model of the rotating body core block is obtained through reconstruction in step S2, for example, Figure 6 As shown in the figure, according to the size and processing accuracy requirements, the tolerance grade corresponding to the dish depth, dish diameter and shoulder width is selected. As a commonly used precision machinery, the corresponding tolerance band grade is IT5, and the basic size segment is 10-18mm. By looking up the standard tolerance data table (such as GB / T 1800.3-1988), it can be obtained that the corresponding lower tolerance band range is 8μm. Based on this, the cross-sectional circle ( Figure 6 The target tolerance zone of the cross-sectional circle 1) in the geometric structure is determined, and the cross-sectional circle ( Figure 6 The target tolerance zone of the cross-sectional circle 2) in the cone surface is determined, and the bottom circle of the conical surface geometric feature ( Figure 6 The target tolerance zone of the cone base in the figure is determined, and the target tolerance zone of the lowest point Q of the spherical geometric element is determined at the same time.

[0111] In the present application, step S3 may include: determining the radius of the cross-section circle and the radius of the base circle of the conical surface geometric element in the mathematical relationship model of the geometric structure; determining the tolerance zone corresponding to the radius of the cross-section circle in the preset tolerance zone mapping relationship according to the radius of the cross-section circle, the radius of the base circle and the preset tolerance zone mapping relationship, and determining the tolerance zone corresponding to the radius of the base circle; determining the tolerance zone corresponding to the radius of the cross-section circle as the target tolerance zone corresponding to the cross-section circle, and determining the tolerance zone corresponding to the base circle as the target tolerance zone corresponding to the base circle; obtaining and determining the tolerance zone corresponding to the point element in the preset tolerance zone mapping relationship, and determining the tolerance zone as the target tolerance zone corresponding to the lowest point of the spherical geometric element.

[0112] In this embodiment, due to the different sizes or shapes of rotating body core blocks, the tolerance ranges of various key dimensions will be different. Therefore, the present application pre-constructs a preset tolerance zone mapping relationship, in which the preset tolerance zone mapping relationship records rotating body core blocks of various sizes or shapes, each rotating body core block has a corresponding set of tolerance zone mapping relationships, and a set of tolerance zone mapping relationships records the tolerance zone ranges corresponding to each key dimension in the rotating body core block type corresponding to the set of tolerance zone mapping relationships. For the rotating body core block of the present application, first determine the radius of the cross-section circle and the radius of the bottom circle of the conical surface geometric element in the corresponding geometric structure mathematical relationship model. Then, a group of tolerance zone mapping relationships corresponding to the rotating body core block is located from the preset tolerance zone mapping relationships, and the tolerance zone corresponding to the cross-sectional circle at the intersection of the plane geometric elements and the spherical geometric elements in the geometric structure mathematical relationship model is found from the group of tolerance zone mapping relationships, and the tolerance zone is determined as the target tolerance zone of the cross-sectional circle; and the tolerance zone corresponding to the cross-sectional circle at the intersection of the plane geometric elements and the conical surface geometric elements in the geometric structure mathematical relationship model is found from the group of tolerance zone mapping relationships, and the tolerance zone is determined as the target tolerance zone of the cross-sectional circle; and the tolerance zone corresponding to the bottom circle of the conical surface in the geometric structure mathematical relationship model is found from the group of tolerance zone mapping relationships, and the tolerance zone is determined as the target tolerance zone of the bottom circle; and the tolerance zone corresponding to the lowest point of the spherical geometric element in the geometric structure mathematical relationship model is found from the group of tolerance zone mapping relationships, and the tolerance zone is determined as the target tolerance zone of the lowest point of the spherical geometric element.

[0113] Step S4: constructing a standard tolerance model of the rotating body core block according to the target tolerance zone and the geometric structure mathematical relationship model.

[0114] In this embodiment, after obtaining the target tolerance zones corresponding to each cross-sectional circle, the bottom circle of the conical surface geometric element, and the lowest point of the spherical surface geometric element, the corresponding target tolerance zones are considered in the equations involving each cross-sectional circle, the bottom circle of the conical surface geometric element, and the lowest point of the spherical surface geometric element in the geometric structure mathematical relationship model constructed in step S2, so as to construct and obtain the standard tolerance model corresponding to the rotating body core block. For example, the following equations are used in the corresponding equations in the geometric structure mathematical relationship model constructed in step S2: Figure 2 The radius of the cross-sectional circle 1 is Sr1, and when the target tolerance zone corresponding to the radius Sr1 is [-8μm, 8μm], the radius of the cross-sectional circle 1 is taken as r1=[Sr1-8μm, Sr1+8μm].

[0115] Step S5: collecting point cloud data of the target rotating body core block obtained by machining, and constructing a three-dimensional model of the target rotating body core block.

[0116] In this embodiment, after completing the processing of the above-mentioned steps S1 to S4, the target rotating body core block obtained by processing and having actual processing errors is scanned by a three-dimensional scanning device, and a three-dimensional model corresponding to the target rotating body core block is constructed based on the point cloud data of the target rotating body core block obtained by scanning.

[0117] Step S6: According to the standard tolerance model, the point cloud data in the three-dimensional model is screened by tolerance neighborhood to obtain a target three-dimensional model.

[0118] In this embodiment, according to the standard tolerance model created in step S4, the point cloud data of the three-dimensional model created in step S5 is subjected to neighborhood screening. At this time, the neighborhood screening out is the point cloud data within the range of each target tolerance band recorded in the standard tolerance model, and a corresponding target three-dimensional model is created based on the screened point cloud data within the range of each target tolerance band. Figure 7 As shown, Figure 7 The corresponding target three-dimensional model is exemplarily shown as being created based on the point cloud data within the target tolerance range of the screened cross-sectional circle 1, cross-sectional circle 2, cone bottom circle and spherical area lowest point.

[0119] Step S7: Determine the actual measurement value of each dimension to be detected according to the target three-dimensional model, wherein the dimensions to be detected include the disc diameter dimension, disc depth dimension, shoulder width dimension, chamfer height dimension and chamfer width dimension of the intersection of geometric elements.

[0120] In this embodiment, after obtaining the target three-dimensional model after neighborhood screening in step S6, the point cloud data within the range of a single target tolerance zone in the target three-dimensional model is fitted to obtain the fitting results corresponding to each target tolerance zone. The fitting results are brought into the geometric structure mathematical relationship model for solution to obtain the actual measurement values ​​of each dimension to be detected.

[0121] The embodiment of the present application provides a method for detecting the three-dimensional size of a core block based on neighborhood screening. First, according to the processing size of the rotating core block, the geometric elements and geometric spatial relationships of the rotating core block are analyzed by line and surface to obtain various geometric elements of the rotating core block and the geometric spatial relationships between various geometric elements of the rotating core block. Various geometric elements include spherical geometric elements, plane geometric elements and conical surface geometric elements; according to various geometric elements of the rotating core block and the geometric spatial relationships between various geometric elements, a geometric structure mathematical relationship model generated by the intersection of various geometric elements under the geometric spatial relationship is determined; the intersection of geometric elements in the geometric structure mathematical relationship model is determined. The target tolerance zone corresponding to the cross-sectional circle; constructing a standard tolerance model of the rotating body core block according to the target tolerance zone and the mathematical relationship model of the geometric structure; collecting point cloud data of the target rotating body core block obtained by processing, and constructing a three-dimensional model of the target rotating body core block; according to the standard tolerance model, performing tolerance neighborhood screening on the point cloud data in the three-dimensional model to obtain the target three-dimensional model; according to the target three-dimensional model, determining the actual measurement value of each dimension to be detected, wherein the dimensions to be detected include the dish diameter dimension, dish depth dimension, shoulder width dimension, chamfer height dimension and chamfer width dimension where the geometric elements intersect. Therefore, in the process of detecting rotating nuclear fuel core blocks, the present application first constructs a geometric structure mathematical model relationship model through line and surface analysis of geometric elements and geometric space relationships, and then constructs a standard tolerance model of the rotating nuclear fuel core blocks by introducing tolerance bands. Then, the standard tolerance model is used to perform neighborhood screening on the three-dimensional model composed of all point cloud data scanned and collected for the target rotating core blocks obtained by actual processing, and the rotating core blocks are detected in the screened point cloud data to determine the actual measured values ​​of each dimension to be detected of the target rotating core blocks obtained by actual processing. This greatly reduces the regional range of data points in the size calculation and simplifies the amount of data that needs to be processed and calculated. At the same time, the process utilizes the analysis results of geometric elements and can also be more conveniently and efficiently applied to the calculation of size data of three-dimensional point cloud data.

[0122] In combination with the above embodiments, in one implementation, the present application also provides a method for detecting the three-dimensional size of a core block based on neighborhood screening. In this method, step S5 may include steps S51 to S54:

[0123] Step S51: rotating the core block of the target rotating body at an angle parallel to the horizontal plane and performing multi-angle parallel projection to obtain corresponding multiple projection planes.

[0124] In this embodiment, since the processing accuracy of the core block is relatively high in the field of nuclear fuel, the interference of various external factors also needs to be considered during measurement. In this process, the measurement platform is contaminated (such as some dust particles, the measurement platform has inevitable mechanical installation errors due to differences in processing accuracy, etc.), which will cause the target rotating body core block placed therein for measurement to tilt to a certain extent. If the influence of this tilt is ignored, the accuracy of the measurement result will be reduced. Therefore, in order to avoid this situation, the present application will determine the rotation center axis of the target rotating body core block after it is placed on the measurement platform, and then control the three-dimensional scanning device to scan the target rotating body core block in a manner perpendicular to the rotation center axis, so as to avoid the above-mentioned problem.

[0125] Specifically, after placing the target rotating body core block on the measuring platform, the target rotating body core block is rotated at multiple different angles parallel to the horizontal plane to perform parallel projection, thereby obtaining multiple corresponding projection planes.

[0126] Step S52: Determine the rotation center axis of the target rotating body core block based on the multiple projection planes.

[0127] In this embodiment, after obtaining multiple projection surfaces of the target rotating body core block at different angles through step S51, the specific tilt direction and tilt angle of the target rotating body core block are determined by calculating the multiple projection surfaces at different angles, and the rotation center axis of the target rotating body core block placed on the measuring platform is determined based on the tilt direction and tilt angle.

[0128] Step S53: Scanning the target rotating body core block in a direction perpendicular to the rotation center axis by means of a scanning device to obtain a corresponding point cloud data set.

[0129] In this embodiment, after the rotation center axis of the target rotating body core block placed on the measuring platform is determined through step S52, the target rotating body core block is scanned by a three-dimensional scanning device in a direction that is always perpendicular to the rotation center axis. For the top surface of the target rotating body core block, the axis of the three-dimensional scanning device is controlled to scan the top surface of the target rotating body core block at an angle colinear with the rotation center axis to obtain a complete point cloud data set corresponding to the target rotating body core block.

[0130] Step S54: constructing a three-dimensional model of the target rotating body core block based on the point cloud data set.

[0131] In this embodiment, based on the point cloud data set collected in step S53, a three-dimensional model corresponding to the core block of the target rotating body is constructed and generated.

[0132] In combination with the above embodiments, in one implementation, the present application also provides a method for detecting the three-dimensional size of a core block based on neighborhood screening. In this method, step S6 may include steps S61 to S64:

[0133] Step S61: performing denoising processing on the three-dimensional model to obtain a denoised three-dimensional model.

[0134] In this embodiment, there are inevitably some noise impurities and redundant data in the large amount of point cloud data collected. Therefore, this application first denoises the constructed three-dimensional model to remove the noise in the three-dimensional model constructed by the point cloud data set, so as to obtain the corresponding denoised three-dimensional model, which is the denoised three-dimensional model.

[0135] Step S62: According to the denoised three-dimensional model, a reference axis in the denoised three-dimensional model is determined, where the reference axis is an axis that passes through the coordinates of the center of a spherical geometric element in the denoised three-dimensional model and through the lowest point of the spherical geometric element.

[0136] In this embodiment, after obtaining the denoised three-dimensional model through step S62, based on the denoised three-dimensional model, the corresponding spherical center coordinates are determined by fitting the point cloud data related to the spherical geometric elements in the denoised three-dimensional model, and the axis passing through the spherical center coordinates and the lowest point of the spherical geometric elements is determined as the reference axis in the denoised three-dimensional model.

[0137] In the present application, based on the denoised three-dimensional model, the reference axis in the denoised three-dimensional model is determined, including: obtaining point cloud data related to spherical geometric elements in the denoised three-dimensional model; performing spherical fitting on the point cloud data related to the spherical geometric elements to determine the center coordinates and spherical radius of the spherical geometric elements in the denoised three-dimensional model; and determining the reference axis in the denoised three-dimensional model based on the center coordinates.

[0138] In this embodiment, point cloud data related to spherical geometric elements in the denoised three-dimensional model is obtained, and spherical fitting is performed on the point cloud data to obtain the center coordinates and radius of the sphere, and thereby determine the spherical center line L1 passing through the center coordinates and the lowest point of the sphere. The spherical center line also corresponds to the reference axis of the denoised three-dimensional model.

[0139] In this embodiment, in the space coordinate system, the spherical equation is

[0140] , the deformation is obtained

[0141] , simplified to get

[0142] ,in , , , ,also, , . Written in matrix form

[0143] , convert it into the matrix form of the least squares method, perform least squares fitting, and after obtaining a1, b1, c1, and d1, r1 can be further calculated.

[0144] After fitting, the values ​​of a1, b1, c1 and r1 are obtained, such as a1=p1, b1=p2, c1=p3, r1=p4. The reference axis of the denoised 3D model is along the z-axis. At this time, the equation of the reference axis L is In addition, the coordinates of the lowest point Q of the fitted sphere are consistent with the determination method of the spherical center line L1 of the spherical area, and are the lowest point generated after fitting within the spherical area. In this embodiment, the determination method is consistent with the reference axis L, and there is no need to determine the geometric tolerance range again. The coordinates of point Q are (p1, p2, p5), where p5=p3-p4.

[0145] Step S63: According to the target tolerance zone in the standard tolerance model and the reference axis, the point cloud data set within the target tolerance zone in the denoised three-dimensional model is screened.

[0146] In this embodiment, after the reference axis in the denoised three-dimensional model is determined, the point cloud data sets within each target tolerance zone in the denoised three-dimensional model are screened out based on the reference axis and the standard tolerance model.

[0147] Step S64: construct a target three-dimensional model based on the filtered point cloud data set.

[0148] In this embodiment, a target three-dimensional model corresponding to the target rotating body core block is constructed based on the screened point cloud data sets within the range of each target tolerance zone.

[0149] In combination with the above embodiments, in one implementation, the present application also provides a method for detecting the three-dimensional size of a core block based on neighborhood screening. In this method, step S63 may include steps S631 to S633:

[0150] Step S631: Based on the first range formula of the target tolerance zone corresponding to the reference axis and the first cross-sectional circle on the two-dimensional coordinate plane , filter the point cloud data that meets the first range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance zone corresponding to the first section circle, where (p1, p2) represents the center coordinates of the first section circle on the two-dimensional coordinate plane, and ra represents the range of increasing and decreasing the corresponding target tolerance zone by half on the standard radius of the first section circle.

[0151] In this embodiment, when the reference axis of the denoised three-dimensional model is determined, the first cross-sectional circle (such as Figure 2 The target tolerance zone area corresponding to the cross-section circle 1) in the figure can be converted into a circular area with a tolerance value twice the corresponding target tolerance zone based on the standard radius of the first cross-section circle. At this time, the first range formula of the target tolerance zone corresponding to the first cross-section circle on the two-dimensional coordinate plane is: , filter all point cloud data that meet the first range formula in the denoised three-dimensional model, and determine all the filtered point cloud data as the point cloud data set within the target tolerance range corresponding to the first section circle. Among them, (p1, p2) represents the coordinates of the center of the first section circle on the two-dimensional coordinate plane, and ra represents the range of increasing and decreasing half of the corresponding target tolerance range on the standard radius of the first section circle. For example, when the standard radius of the first section circle is Sr1 and the corresponding target tolerance range is [-8μm, 8μm], then ra=[Sr1-8μm, Sr1+8μm].

[0152] Step S632: A second range formula of the target tolerance zone corresponding to the reference axis and the second cross-section circle on the two-dimensional coordinate plane is used. , filter the point cloud data that meets the second range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance zone corresponding to the second section circle, where (p1, p2) represents the center coordinates of the second section circle on the two-dimensional coordinate plane, and rb represents the range of increasing and decreasing the corresponding target tolerance zone by half on the standard radius of the second section circle.

[0153] In this embodiment, when the reference axis of the denoised three-dimensional model is determined, the second cross-sectional circle (such as Figure 2 The target tolerance zone area corresponding to the cross-section circle 2) in the figure can be converted into a circular area with a tolerance value of twice the corresponding target tolerance zone based on the standard radius of the second cross-section circle. At this time, the second range formula of the target tolerance zone corresponding to the second cross-section circle on the two-dimensional coordinate plane is: , filter all point cloud data that meet the second range formula in the denoised three-dimensional model, and determine all the filtered point cloud data as the point cloud data set within the target tolerance range corresponding to the second section circle. Among them, (p1, p2) represents the coordinates of the center of the second section circle on the two-dimensional coordinate plane, and rb represents the range of increasing and decreasing half of the corresponding target tolerance range on the standard radius of the second section circle. For example, when the standard radius of the second section circle is Sr2 and the corresponding target tolerance range is [-8μm, 8μm], then rb=[Sr2-8μm, Sr2+8μm].

[0154] Step S633: Based on the third range formula of the base circle of the reference axis and the conical surface geometric element on the two-dimensional coordinate plane , filter the point cloud data that meets the third range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance band corresponding to the bottom circle, where (p1, p2) represents the center coordinates of the bottom circle on the two-dimensional coordinate plane, and rc represents the range of increasing and decreasing the corresponding target tolerance band by half on the standard radius of the bottom circle.

[0155] In this embodiment, when the reference axis of the denoised three-dimensional model is determined, the bottom circle of the conical surface geometric element (such as Figure 2 The target tolerance zone area corresponding to the base circle in the figure can be converted into a circular area with a tolerance value twice the target tolerance zone based on the standard radius of the base circle. At this time, the third range formula of the target tolerance zone corresponding to the base circle on the two-dimensional coordinate plane is: , filter all point cloud data that meet the third range formula in the denoised 3D model, and determine all the filtered point cloud data as the point cloud data set within the target tolerance range corresponding to the bottom circle. Among them, (p1, p2) represents the center coordinates of the bottom circle on the two-dimensional coordinate plane, and rc represents the range of increasing and decreasing half of the corresponding target tolerance range on the standard radius of the bottom circle. For example, when the standard radius of the bottom circle is r3 and the corresponding target tolerance range is [-8μm, 8μm], then rc = [r3-8μm, r3+8μm].

[0156] In combination with the above embodiments, in one implementation, the present application also provides a method for detecting the three-dimensional size of a core block based on neighborhood screening. In this method, step S7 may include steps S71 to S78:

[0157] Step S71: When the size to be detected is a disc diameter size, the point cloud data set within the target tolerance band corresponding to the first section circle is fitted using the least squares circle fitting formula to obtain the actual measurement value of the radius of the first section circle in the target three-dimensional model.

[0158] In this embodiment, if Figure 8As shown, Figure 8 It shows that the present application is mainly applied to Figure 2 For the disc diameter size Sd1, the point cloud data set within the target tolerance band corresponding to the first section circle selected by step S631 is fitted by the least squares circle fitting formula to obtain the actual measured value of the radius Sr1 of the first section circle in the target three-dimensional model, as shown in FIG. Fig. 9 As shown, Fig. 9 The actual result of the cross-sectional circle 1 of the target rotating body core block obtained by fitting the point cloud data set within the target tolerance band corresponding to the cross-sectional circle 1 is shown.

[0159] Step S72: determining the actual measured value of the radius of the first cross-section circle in the target three-dimensional model as the actual measured value of the disk diameter size corresponding to the target three-dimensional model.

[0160] In this embodiment, the actual measured value of the radius Sr1 of the first cross-section circle in the target three-dimensional model determined in step S71 is determined as the actual measured value of the disk diameter size Sd1 corresponding to the target three-dimensional model.

[0161] Step S73: When the dimension to be detected is a dish-shaped depth dimension, the actual measurement value of the radius of the first cross-sectional circle in the target three-dimensional model and the actual measurement value of the spherical radius of the spherical geometric element in the target three-dimensional model are brought into the dish-shaped depth algorithm for calculation to obtain the actual measurement value of the dish-shaped depth dimension. The actual measurement value of the spherical radius is synchronously determined in the process of performing spherical fitting on the point cloud data related to the spherical geometric element and determining the center coordinates of the spherical geometric element in the denoised three-dimensional model.

[0162] In this embodiment, for the dish depth dimension dt1, the actual measured value of the radius Sr1 of the first cross-section circle in the target three-dimensional model determined in step S71 and the actual measured value of the spherical radius r1 of the spherical geometric element in the target three-dimensional model are brought into the dish depth algorithm in the geometric structure mathematical relationship model for calculation to obtain the actual measured value of the dish depth dimension dt1 corresponding to the target three-dimensional model. Among them, the actual measured value of the spherical radius r1 of the spherical geometric element in the target three-dimensional model has been determined in the process of determining the spherical center coordinates of the spherical geometric element in the denoised three-dimensional model, and there is no need to re-determine it here and it can be directly used.

[0163] Step S74: When the dimension to be detected is the shoulder width dimension, the point cloud data set within the target tolerance band corresponding to the second section circle is fitted by the least squares circle fitting formula to obtain the actual measurement value of the radius of the second section circle in the target three-dimensional model.

[0164] In this embodiment, for the shoulder width dimension w, the point cloud data set within the target tolerance band corresponding to the second section circle screened out in step S632 is fitted using the least squares circle fitting formula to obtain the actual measurement value of the radius Sr2 of the second section circle in the target three-dimensional model.

[0165] Step S75: subtract the calculated actual measurement value of the radius of the first cross-section circle in the target three-dimensional model from the calculated actual measurement value of the radius of the second cross-section circle in the target three-dimensional model to obtain the actual measurement value of the shoulder width.

[0166] In this embodiment, the actual measured value of the radius of the second cross-sectional circle in the target three-dimensional model is subtracted from the actual measured value of the radius of the first cross-sectional circle in the target three-dimensional model to obtain the actual measured value of the shoulder width dimension.

[0167] Step S76: When the dimension to be detected is the chamfer width dimension, the point cloud data set within the target tolerance band corresponding to the bottom circle is fitted using the least squares circle fitting formula to obtain the actual measured value of the radius of the bottom circle in the target three-dimensional model and the axial average value of the bottom circle perpendicular to the plane geometric elements.

[0168] In this embodiment, for the chamfer width dimension Cw, the point cloud data set within the target tolerance band corresponding to the bottom circle of the cone surface screened out in step S633 is fitted using the least squares circle fitting formula to obtain the actual measured value of the radius r3 of the bottom circle of the cone surface in the target three-dimensional model.

[0169] Step S77: subtract the calculated actual measurement value of the radius of the second cross-section circle in the target three-dimensional model from the actual measurement value of the radius of the bottom circle in the target three-dimensional model to obtain the actual measurement value of the chamfer width.

[0170] In this embodiment, the actual measured value of the radius of the bottom circle of the conical surface in the target three-dimensional model is subtracted from the actual measured value of the radius of the second cross-section circle in the target three-dimensional model to obtain the actual measured value of the chamfer width Cw.

[0171] Step S78: When the dimension to be detected is the chamfer height dimension, the axial value perpendicular to the plane geometric element is subtracted from the axial average value perpendicular to the plane geometric element in the bottom circle to obtain the chamfer height dimension.

[0172] In this embodiment, the direction perpendicular to the plane geometric element is determined to be the z-axis direction. For the chamfer height dimension Ch, the z-axis coordinate values ​​of the point cloud data set within the target tolerance band corresponding to the base circle of the cone surface are averaged to obtain the axial average value perpendicular to the plane geometric element in the base circle. Then, the axial value of the plane geometric element (that is, the z-axis value) is subtracted from the axial average value to obtain the actual measured value of the chamfer height dimension Ch.

[0173] In combination with the above embodiments, in one implementation, the present application also provides a method for detecting the three-dimensional size of a core block based on neighborhood screening. In the method, the method further includes steps S8 to S9:

[0174] Step S8: Determine the deviation between the actual measured value of the to-be-detected dimension of the target rotating body core block and the standard value of the to-be-detected dimension.

[0175] In this embodiment, after obtaining the actual measured values ​​of each dimension to be detected of the target rotating body core block through the above-mentioned steps S71 to S78, the deviations between the actual measured values ​​of each dimension to be detected and their corresponding standard values ​​are determined, such as the deviation between the actual measured value of the dish diameter dimension and the standard value of the dish diameter dimension, the deviation between the actual measured value of the shoulder width dimension and the standard value of the shoulder width dimension, etc.

[0176] Step S9: Determine the machining result of the target rotating body core block according to the standard tolerance model and the deviation.

[0177] In this embodiment, the target tolerance zone corresponding to each cross-sectional circle and the target tolerance zone corresponding to the bottom circle of the conical surface geometric element are recorded in the standard tolerance model, which ultimately manifests itself as the radius of each circle can fluctuate within a range, and the parameters of the radius of these circles are required in the calculation process of each dimension to be detected. Accordingly, the allowable deviation range of each dimension to be detected can be determined based on the standard tolerance model. Based on the deviation between the actual measured value and the standard value of the dimension to be detected and the allowable deviation range of each dimension to be detected determined based on the standard tolerance model, it can be determined whether each dimension to be detected of the target rotating body core block to be processed is within its corresponding allowable error range, thereby obtaining the processing result of the target rotating body core block.

[0178] In combination with the above embodiments, in one implementation, the embodiments of the present application also provide a method for detecting three-dimensional dimensions of core blocks based on neighborhood screening. In this method, determining the standard values ​​of each dimension to be detected in the geometric structure mathematical relationship model may include: when the dimension to be detected is a dish diameter dimension, calculating the radius of the first cross-sectional circle generated by the intersection of the spherical geometric element and the plane geometric element, and determining the radius of the first cross-sectional circle to be the standard value of the dish diameter dimension; when the dimension to be detected is a dish depth dimension, fitting the spherical geometric element through the spherical equation to obtain the spherical radius of the spherical geometric element; by substituting the spherical radius and the radius of the first cross-sectional circle into the dish depth algorithm for calculation, the standard value of the dish depth dimension is obtained, and the dish depth algorithm expression is: , where dt1 is the value of the dish depth dimension, r1 is the spherical radius, and Sr1 is the radius of the first section circle; when the dimension to be detected is the shoulder width dimension, calculate the standard value of the radius of the second section circle generated by the intersection of the conical surface geometric element and the plane geometric element; subtract the standard value of the radius of the first section circle obtained by calculation from the standard value of the radius of the second section circle to obtain the standard value of the shoulder width dimension; when the dimension to be detected is the chamfer width dimension, obtain the standard value of the radius of the bottom circle of the conical surface by fitting the conical surface geometric elements; subtract the standard value of the radius of the bottom circle from the standard value of the radius of the second section circle to obtain the standard value of the chamfer width dimension; when the dimension to be detected is the chamfer height dimension, determine the distance between the bottom surface of the conical surface geometric element and the plane geometric element as the standard value of the chamfer height dimension.

[0179] In this embodiment, for the standard value of the disk diameter size Sd1, the standard value of the radius Sr1 of the first cross-sectional circle generated by the intersection of the spherical geometric element and the plane geometric element is calculated, and the standard value of the radius Sr1 of the first cross-sectional circle is determined as the standard value of the disk diameter size Sd1.

[0180] In this embodiment, for the standard value of the dish depth dimension dt1, the spherical geometric elements are fitted by the spherical equation to obtain the spherical center coordinates and spherical radius of the spherical geometric elements. The standard value of the dish depth dimension is obtained by bringing the obtained spherical radius r1 and the radius Sr1 of the first cross-section circle into the dish depth algorithm for calculation. The dish depth algorithm expression is: , where dt1 is the value of the dish depth, r1 is the spherical radius, and Sr1 is the radius of the first section circle.

[0181] In this embodiment, for the standard value of the shoulder width dimension w, the standard value of the radius Sr2 of the second cross-sectional circle generated by the intersection of the conical surface geometric elements and the plane geometric elements is calculated; the standard value of the radius Sr1 of the first cross-sectional circle obtained by calculation and the standard value of the radius Sr2 of the second cross-sectional circle are subtracted to obtain the standard value of the shoulder width dimension w.

[0182] In this embodiment, for the standard value of the chamfer width dimension Cw, the standard value of the radius r3 of the base circle of the cone is obtained by fitting the geometric elements of the cone surface, and the standard value of the radius r3 of the base circle is subtracted from the standard value of the radius Sr2 of the second cross-section circle to obtain the standard value of the chamfer width dimension Cw.

[0183] In this embodiment, for the chamfer height dimension Ch, the distance between the bottom surface of the conical surface geometric element and the plane geometric element is determined as the standard value of the chamfer height dimension Ch.

[0184] In combination with the above embodiments, in one implementation, the present application also provides a method for detecting the three-dimensional size of a core block based on neighborhood screening. In this method, step S9 may include steps S91 to S92:

[0185] Step S91: when the deviations of all the dimensions to be detected are within the corresponding target tolerance bands, determining that the machining result of the target rotating body core block is qualified.

[0186] In this embodiment, based on the deviation between the actual measured value of the to-be-detected dimension and the standard value and the allowable deviation range of each to-be-detected dimension determined based on the standard tolerance model, it can be determined whether each to-be-detected dimension of the target rotating body core block to be processed is within its corresponding allowable error range. When the deviations of all to-be-detected dimensions are within their respective corresponding allowable error ranges, it is determined that the processing result of the target rotating body core block is qualified.

[0187] Step S92: when the deviation of the dimension to be detected is greater than the target tolerance range, determining that the machining result of the target rotating body core block is unqualified.

[0188] In this embodiment, when the deviation of one or more dimensions to be detected among all the dimensions to be detected is greater than the corresponding allowable error range, it is determined that the machining result of the target rotating body core block is unqualified.

[0189] It should be noted that, for the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present application are not limited by the described order of actions, because according to the embodiments of the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present application.

[0190] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0191] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the embodiments of the present application may adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the embodiments of the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0192] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present application.

[0193] The above is a detailed introduction to a core block three-dimensional size detection method based on neighborhood screening provided by the present application. This article uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for detecting three-dimensional size of a core block based on neighborhood screening, characterized in that: The method comprises: According to the processing size of the rotating body core block, the geometric elements and geometric space relationship of the rotating body core block are analyzed by line and surface to obtain various geometric elements of the rotating body core block and the geometric space relationship between various geometric elements of the rotating body core block, wherein the various geometric elements include spherical geometric elements, plane geometric elements and conical geometric elements; According to various geometric elements of the rotating body core block and the geometric spatial relationship between the various geometric elements, a geometric structure mathematical relationship model corresponding to the rotating body core block is constructed; Determine the target tolerance zones corresponding to the cross-sectional circles at the intersections of the geometric elements in the geometric structure mathematical relationship model, the bottom circles of the conical geometric elements, and the lowest points of the spherical geometric elements; Constructing a standard tolerance model of the rotating body core block according to the target tolerance zone and the geometric structure mathematical relationship model; Performing point cloud data collection on the target rotating body core block obtained by machining to construct a three-dimensional model of the target rotating body core block; According to the standard tolerance model, performing tolerance neighborhood screening on the point cloud data in the three-dimensional model to obtain a target three-dimensional model; According to the target three-dimensional model, the actual measurement value of each size to be detected is determined, wherein the size to be detected includes the disc diameter size, disc depth size, shoulder width size, chamfer height size and chamfer width size where the geometric elements intersect.

2. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 1, characterized in that: Determining the target tolerance zones corresponding to the cross-sectional circles at the intersections of the geometric elements in the geometric structure mathematical relationship model, the bottom circles of the conical geometric elements, and the lowest points of the spherical geometric elements, respectively, includes: Determine the radius of the cross-section circle and the radius of the base circle of the conical surface geometric element in the geometric structure mathematical relationship model; According to the radius of the cross-section circle, the radius of the bottom circle and the preset tolerance zone mapping relationship, determine the tolerance zone corresponding to the radius of the cross-section circle in the preset tolerance zone mapping relationship, and determine the tolerance zone corresponding to the radius of the bottom circle; Determine the tolerance zone corresponding to the radius of the cross-sectional circle as the target tolerance zone corresponding to the cross-sectional circle, and determine the tolerance zone corresponding to the bottom surface circle as the target tolerance zone corresponding to the bottom surface circle; The tolerance zone corresponding to the point element in the preset tolerance zone mapping relationship is obtained and determined, and the tolerance zone is determined as the target tolerance zone corresponding to the lowest point of the spherical geometric element.

3. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 1, characterized in that: The point cloud data of the target rotating body core block obtained by machining is collected to construct a three-dimensional model of the target rotating body core block, including: Rotating the core block of the target rotating body at an angle parallel to the horizontal plane to perform multi-angle parallel projection to obtain corresponding multiple projection planes; Determining the rotation center axis of the target rotating body core block according to the plurality of projection planes; Scanning the target rotating body core block in a direction perpendicular to the rotation center axis by a scanning device to obtain a corresponding point cloud data set; Based on the point cloud data set, a three-dimensional model of the target rotating body core block is constructed.

4. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 1, characterized in that: According to the standard tolerance model, performing tolerance neighborhood screening on the point cloud data in the three-dimensional model to obtain a target three-dimensional model includes: Performing denoising processing on the three-dimensional model to obtain a denoised three-dimensional model; According to the denoised three-dimensional model, determining a reference axis in the denoised three-dimensional model, wherein the reference axis is an axis passing through the coordinates of the center of a spherical geometric element in the denoised three-dimensional model and passing through the lowest point of the spherical geometric element; According to the target tolerance zone in the standard tolerance model and the reference axis, screening the point cloud data set within the target tolerance zone in the denoised three-dimensional model; Construct the target 3D model based on the filtered point cloud dataset.

5. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 4, characterized in that: Determining a reference axis in the denoised three-dimensional model according to the denoised three-dimensional model includes: Acquire point cloud data related to spherical geometric elements in the denoised three-dimensional model; Performing spherical fitting on the point cloud data related to the spherical geometric elements to determine the spherical center coordinates and spherical radius of the spherical geometric elements in the denoised three-dimensional model; According to the spherical center coordinates, a reference axis in the denoised three-dimensional model is determined.

6. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 4, characterized in that: According to the target tolerance zone in the standard tolerance model and the reference axis, a point cloud data set within the target tolerance zone in the denoised three-dimensional model is screened, including: According to the first range formula of the target tolerance zone corresponding to the reference axis and the first section circle on the two-dimensional coordinate plane , filter the point cloud data that meets the first range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance zone corresponding to the first section circle, where (p1, p2) represents the center coordinates of the first section circle on the two-dimensional coordinate plane, and ra represents the range of increasing and decreasing the corresponding target tolerance zone by half on the standard radius of the first section circle; According to the second range formula of the target tolerance zone corresponding to the reference axis and the second section circle on the two-dimensional coordinate plane , filter the point cloud data that meets the second range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance zone corresponding to the second section circle, where (p1, p2) represents the center coordinates of the second section circle on the two-dimensional coordinate plane, and rb represents the range of increasing and decreasing the corresponding target tolerance zone by half on the standard radius of the second section circle; According to the third range formula of the base circle of the reference axis and the conical surface geometric element on the two-dimensional coordinate plane , filter the point cloud data that meets the third range formula in the denoised three-dimensional model, and obtain the point cloud data set within the target tolerance band corresponding to the bottom circle, where (p1, p2) represents the center coordinates of the bottom circle on the two-dimensional coordinate plane, and rc represents the range of increasing and decreasing the corresponding target tolerance band by half on the standard radius of the bottom circle.

7. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 6, characterized in that: According to the target three-dimensional model, determining the actual measurement value of each dimension to be detected includes: When the size to be detected is a dish diameter size, the point cloud data set within the target tolerance band corresponding to the first section circle is fitted by the least squares circle fitting formula to obtain the actual measurement value of the radius of the first section circle in the target three-dimensional model; Determine the actual measured value of the radius of the first cross-section circle in the target three-dimensional model as the actual measured value of the disk diameter size corresponding to the target three-dimensional model; In the case where the size to be detected is a dish depth size, the actual measurement value of the dish depth size is obtained by bringing the actual measurement value of the radius of the first cross-section circle in the target three-dimensional model and the actual measurement value of the spherical radius of the spherical geometric element in the target three-dimensional model into the dish depth algorithm for calculation, and the actual measurement value of the spherical radius is synchronously determined in the process of performing spherical fitting on the point cloud data related to the spherical geometric element and determining the spherical center coordinates of the spherical geometric element in the denoised three-dimensional model; When the dimension to be detected is the shoulder width dimension, the point cloud data set within the target tolerance band corresponding to the second section circle is fitted by the least squares circle fitting formula to obtain the actual measurement value of the radius of the second section circle in the target three-dimensional model; Subtracting the calculated actual measurement value of the radius of the first cross-section circle in the target three-dimensional model from the calculated actual measurement value of the radius of the second cross-section circle in the target three-dimensional model to obtain the actual measurement value of the shoulder width; When the dimension to be detected is the chamfer width dimension, the point cloud data set within the target tolerance band corresponding to the bottom circle is fitted by the least squares circle fitting formula to obtain the actual measured value of the radius of the bottom circle in the target three-dimensional model and the axial average value of the bottom circle perpendicular to the plane geometric elements; Subtracting the calculated actual measurement value of the radius of the second cross-section circle in the target three-dimensional model from the actual measurement value of the radius of the bottom circle in the target three-dimensional model to obtain the actual measurement value of the chamfer width; When the dimension to be detected is the chamfer height dimension, the axial value perpendicular to the plane geometric element is subtracted from the axial average value perpendicular to the plane geometric element in the bottom circle to obtain the chamfer height dimension.

8. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 1, characterized in that: The method further comprises: Determine the deviation between the actual measured value of the to-be-detected dimension of the target rotating body core block and the standard value of the to-be-detected dimension; A machining result of the target rotating body core block is determined according to the standard tolerance model and the deviation.

9. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 8, characterized in that: Determining the standard value of each dimension to be detected in the geometric structure mathematical relationship model includes: When the size to be detected is a disk-shaped diameter size, the radius of a first cross-sectional circle generated by the intersection of the spherical geometric element and the plane geometric element is calculated, and the radius of the first cross-sectional circle is determined to be a standard value of the disk-shaped diameter size; When the size to be detected is a dish-shaped depth size, the spherical radius of the spherical geometric element is obtained by fitting the spherical geometric element through the spherical equation; the standard value of the dish-shaped depth size is obtained by bringing the spherical radius and the radius of the first cross-sectional circle into the dish-shaped depth algorithm for calculation. The expression of the dish-shaped depth algorithm is: , where dt1 is the value of the dish depth, r1 is the spherical radius, and Sr1 is the radius of the first section circle; When the dimension to be detected is the shoulder width dimension, the standard value of the radius of the second cross-section circle generated by the intersection of the conical surface geometric element and the plane geometric element is calculated; the standard value of the radius of the first cross-section circle obtained by calculation is subtracted from the standard value of the radius of the second cross-section circle to obtain the standard value of the shoulder width dimension; When the dimension to be detected is the chamfer width dimension, the standard value of the radius of the bottom circle of the conical surface is obtained by fitting the geometric elements of the conical surface; the standard value of the radius of the bottom circle is subtracted from the standard value of the radius of the second cross-section circle to obtain the standard value of the chamfer width dimension; When the dimension to be detected is the chamfer height dimension, the distance between the bottom surface of the conical surface geometric element and the plane geometric element is determined as the standard value of the chamfer height dimension.

10. The method for detecting three-dimensional size of a core block based on neighborhood screening according to claim 8, characterized in that: Determining the machining result of the target rotating body core block according to the standard tolerance model and the deviation includes: When the deviations of all the dimensions to be detected are within the corresponding target tolerance bands, determining that the machining result of the target rotating body core block is qualified; In the case that the deviation of the dimension to be detected is larger than the target tolerance range, the machining result of the target rotating body core block is determined to be unqualified.

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