Automated screening method for rigid workpiece references
Patent Information
- Application Number
- CN202410322769.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-20
- Publication Date
- 2026-09-29
- Estimated Expiration
- 2044-03-20
AI Technical Summary
[0004]但是，当前行业的开发方式普遍依赖于工程师对基准相关因素的知识积累，导致基准设计结果缺乏客观评价指标，缺乏全局的考虑
[0032]本发明的优点在于：目标工件的质心和功能面可以获知，本发明利用质心和最大功能面来形成可以定量评价主基准定位点合理性的评价值，实现对主基准定位点候选点的定量评价筛选。综合了目标工件的形状、尺寸、装配的情况，且能客观、定量的评价定位点的合理性。
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Abstract
Description
Technical Field
[0001] This invention relates to an automated screening method for rigid workpiece references. Background Technology
[0002] The position of an unpositioned workpiece is uncertain. For example, an unpositioned cuboid workpiece placed in a spatial coordinate system can be translated to different positions along the X, Y, and Z axes, and can also be rotated to different positions around the X, Y, and Z axes. The translation of the workpiece along the X, Y, and Z axes is called the translational degree of freedom, and the rotation of the workpiece around the X, Y, and Z axes is called the rotational degree of freedom. The translational and rotational degrees of freedom used to describe the uncertainty of the workpiece's position are combined to form the workpiece's six degrees of freedom.
[0003] For a workpiece to be assembled correctly, its degrees of freedom must first be restricted. Assuming there is a fixed point in space, and the bottom surface of the workpiece is in contact with that point, then the workpiece's translational degree of freedom along the Z-axis is restricted. For example, the commonly used 3-2-1 positioning principle is the most basic condition for restricting a workpiece's six degrees of freedom in space. However, in actual engineering, depending on the characteristics of the workpiece, over-positioning beyond the 3-2-1 principle is allowed to ensure the reliability of the workpiece positioning. The "3-2-1" positioning principle defines the direction of the primary datum, with three points or surfaces in contact, eliminating three degrees of freedom; for example, three points distributed in a triangle on the XOY plane restrict the translational degree of freedom along the Z-axis, the rotational degree of freedom around the X-axis, and the rotational degree of freedom around the Y-axis. The secondary datum is used for positioning, with two points or lines in contact, eliminating two degrees of freedom; two horizontally placed points on the YOZ plane restrict the workpiece's translational degree of freedom along the Y-axis and the rotational degree of freedom around the Z-axis. The third datum is used to fix and control the rotation of the part; one point eliminates one degree of freedom. For example, a point in the XOZ plane restricts the translational degree of freedom of the workpiece along the X-axis. Therefore, the datum restricts six degrees of freedom, and the 3-2-1 principle holds true.
[0004] However, current industry development methods generally rely on engineers' accumulated knowledge of benchmark-related factors, resulting in a lack of objective evaluation indicators and a lack of holistic consideration in benchmark design results. Poor benchmark design will lead to rework and incur costs for a series of changes, including changes to part structure design, tooling fixtures, and inspection tools. Summary of the Invention
[0005] Based on the lack of objective evaluation indicators and the lack of global consideration in the benchmark design results, this invention focuses on a method that reduces reliance on human experience and provides quantitative evaluation indicators by performing global calculations on the workpiece point cloud. This method aims to select workpiece benchmarks using quantitative indicators.
[0006] The shape of a mechanical part is determined by its surface combination, among which the functional surfaces play a crucial role. Functional surfaces are those that come into contact with or interact with the working medium or other objects. The distance of the centroid projected onto the maximum functional surface and the area of the largest triangle projected onto the maximum functional surface are used as quantitative evaluation indicators to select the workpiece's principal datum.
[0007] The first aspect of this invention aims to provide a method for screening the principal datum of a rigid workpiece by using the centroid and functional surfaces as quantitative evaluation indicators through a traversal calculation scheme.
[0008] The technical solution adopted in this invention is: an automated screening method for rigid workpiece datums, including screening the main datum positioning points of the target workpiece; characterized in that: the goal of main datum screening is to determine 3 main datum positioning points, and before main datum screening, all candidate main datum positioning points of the target workpiece and the centroid of the target workpiece are known; traversing all functional surfaces of the target workpiece, finding the functional surface with the largest area, called the maximum functional surface; obtaining the centroid projection point of the target workpiece's centroid onto the maximum functional surface;
[0009] The candidate points for the main datum positioning are arranged into mutually independent regions, with each region corresponding to a candidate point set, and the number of candidate point sets is ≥3. Three coordinate points are selected, each from a different candidate point set. All triangles are traversed, and the marker point of each triangle is obtained according to the same rules. The first projection point is obtained by projecting the marker point onto the maximum functional surface. The distance between the first projection point and the centroid projection point is used as the first evaluation value. The area formed by the three coordinate points is used as the second evaluation value. The first evaluation value, or the second evaluation value, or the comprehensive evaluation value formed by the first and second evaluation values is used as the screening index for the main datum positioning points.
[0010] The following are possible solutions for the first evaluation value: 1. Form a triangle with every three coordinate points, project each triangle onto the maximum functional surface, and use the area of the projected triangle onto the maximum functional surface as the second evaluation value. 2. Form a triangle with every three coordinate points, and use the area of each triangle as the second evaluation value. 3. Project every three coordinate points onto the maximum functional surface, and use the area of the circle (circumcircle) containing the three coordinate points as the second evaluation value. 4. Project every three coordinate points onto the maximum functional surface, forming a projection triangle with the projection points of the three coordinate points onto the maximum functional surface, and use the area of the inscribed circle of the projection triangle as the second evaluation value. 5. Use the ratio of the area of the inscribed circle to the area of the circumcircle as the second evaluation value. 6. Use the ratio of the area of the circumcircle to the area of the projection triangle as the second evaluation value. 7. Use the ratio of the area of the inscribed circle to the area of the projection triangle as the second evaluation value.
[0011] The second evaluation value options are: 1. Traverse all triangles and obtain the marker point of each triangle according to the same rules. Project the marker point onto the maximum functional surface to obtain the first projection point and calculate the distance between the first projection point and the centroid projection point; 2. Traverse all coordinate sets composed of three points, obtain the circumcircle of the three points, and calculate the center of the circle and the distance between the center of the circumcircle and the centroid of the triangle.
[0012] The formula for calculating the radius of the incircle of a triangle is:
[0013] r = 2*S / (a+b+c)
[0014] Where: r represents the radius of the inscribed circle; S represents the area of the triangle; a represents the length of the first side of the triangle; b represents the length of the second side of the triangle; and c represents the length of the third side of the triangle.
[0015] The formula for calculating the radius of the circumcircle of a triangle is:
[0016]
[0017] Where: p = (a + b + c) / 2; R represents the radius of the circumcircle.
[0018] Furthermore, the coordinates of the three vertices of the triangle corresponding to the largest first evaluation value, the largest second evaluation value, or the maximum value among the comprehensive evaluation values formed by the first and second evaluation values are used as three main reference positioning points.
[0019] Furthermore, using the geometric center of a triangle as its landmark, the first projection point is obtained by projecting the geometric center of each triangle onto the maximum functional surface.
[0020] Furthermore, when using the first evaluation value as the screening criterion, all triangles are traversed to obtain the largest first evaluation value and the corresponding triangle vertex coordinates. If only one set of triangle vertex coordinates has the largest first evaluation value, then that set of vertex coordinates is used as the main reference positioning point, and the second evaluation value is not calculated. If there are multiple sets of triangle vertex coordinates corresponding to the largest first evaluation value, then the second evaluation value is calculated for each set of triangles. The first evaluation value and the second evaluation value of each set of triangles form a comprehensive evaluation value, and the triangle vertex coordinates corresponding to the optimal comprehensive evaluation value are used as the main reference positioning point.
[0021] Furthermore, when using the second evaluation value as the screening criterion, all triangles are traversed to obtain the largest second evaluation value and the corresponding triangle vertex coordinates. If only one set of triangle vertex coordinates has the largest second evaluation value, then that set of vertex coordinates is used as the main reference positioning point, and the first evaluation value is not calculated. If there are multiple sets of triangle vertex coordinates corresponding to the largest second evaluation value, then the first evaluation value is calculated for each set of triangles. The first evaluation value and the second evaluation value of each set of triangles form a comprehensive evaluation value, and the triangle vertex coordinates corresponding to the optimal comprehensive evaluation value are used as the main reference positioning point.
[0022] Furthermore, all triangles are traversed, and the first evaluation value and the second evaluation value are calculated respectively. The comprehensive evaluation value is obtained by weighting the first evaluation value and the second evaluation value. The vertex of the triangle corresponding to the maximum comprehensive evaluation value is taken as the main reference positioning point. If the maximum or minimum comprehensive evaluation value corresponds to multiple triangles, the weights of the first evaluation value and the second evaluation value are reset, and the comprehensive evaluation value is recalculated until a unique triangle corresponding to the maximum or minimum comprehensive evaluation value is obtained, and the main reference positioning point is obtained.
[0023] Furthermore, the coordinates of all candidate points for the main datum positioning of the target workpiece are known. The candidate points are clustered using a clustering algorithm, and the clustered candidate points form at least 3 independent regions; the candidate points in each independent region form a candidate point set.
[0024] An automated screening method for rigid workpiece references comprises the following steps:
[0025] S1. The coordinates of all candidate points for the main datum positioning of the target workpiece are known. The candidate points are clustered using a clustering algorithm, and the clustered candidate points form at least 3 independent regions; the candidate points in each independent region form a candidate point set.
[0026] S2. Randomly select three candidate point sets, select one point from each candidate point set, and form a triangle with the three points. Iterate through all triangle combinations and obtain the geometric center of each triangle.
[0027] S3. Traverse all functional surfaces of the target workpiece, find the functional surface with the largest area, called the maximum functional surface; obtain the centroid of the target workpiece, and project the centroid onto the maximum functional surface to obtain the centroid projection point; the order of S2 and S3 can be interchanged;
[0028] S4. Project the geometric center of each triangle obtained in S2 onto the maximum functional surface to obtain the first projection point. The distance between the first projection point and the centroid projection point is used as the first evaluation value. And, or, project each triangle obtained in S2 onto the maximum functional surface to obtain the triangle projection area. Use the triangle projection area as the second evaluation value.
[0029] S5. Find the maximum first evaluation value and its corresponding triangle. If there is only one triangle, then the three vertices of the triangle are used as three main reference positioning points. If there are multiple triangles corresponding to the maximum first evaluation value, then calculate the second evaluation value for these triangles, take the maximum comprehensive value of the first evaluation value and the second evaluation value, and use the vertex of the triangle corresponding to the maximum comprehensive value as three main reference positioning points.
[0030] Alternatively, S5 can be replaced with: Find the maximum second evaluation value and its corresponding triangle. If there is only one triangle, then the three vertices of the triangle are used as three main reference positioning points. If there are multiple triangles corresponding to the maximum second evaluation value, then calculate the first evaluation value for these triangles, take the maximum combined value of the first evaluation value and the second evaluation value, and use the vertex of the triangle corresponding to the maximum combined value as three main reference positioning points.
[0031] Alternatively, S5 can be replaced with: Calculate the first and second evaluation values for each triangle, calculate the comprehensive evaluation value by weighting the first and second evaluation values, and take the vertex of the triangle with the largest comprehensive evaluation value as the main reference positioning point.
[0032] The advantages of this invention are as follows: the centroid and functional plane of the target workpiece can be known. This invention utilizes the centroid and the maximum functional plane to form an evaluation value that can quantitatively assess the rationality of the main datum positioning point, thereby achieving quantitative evaluation and screening of candidate main datum positioning points. It comprehensively considers the shape, size, and assembly status of the target workpiece, and can objectively and quantitatively evaluate the rationality of the positioning point. Detailed Implementation
[0033] A data filtering method, an automated filtering method for rigid workpiece datums, includes filtering the main datum positioning points of the target workpiece; characterized in that: the goal of main datum filtering is to determine three main datum positioning points, and before main datum filtering, all candidate main datum positioning points of the target workpiece and the centroid of the target workpiece are known; traversing all functional surfaces of the target workpiece, finding the functional surface with the largest area, called the maximum functional surface; obtaining the centroid projection point of the target workpiece's centroid onto the maximum functional surface;
[0034] The candidate points for the main datum positioning are made into mutually independent regions, each region corresponding to a candidate point set, and the number of candidate point sets is ≥3; any three points are selected to form a triangle, and the three points come from different candidate point sets; all triangles are traversed, and the marker point of each triangle is obtained according to the same rules; the marker point is projected onto the maximum functional surface to obtain the first projection point, and the distance between the first projection point and the centroid projection point is used as the first evaluation value; each triangle is projected onto the maximum functional surface, and the area of the triangle projected onto the maximum functional surface is used as the second evaluation value; the first evaluation value, or the second evaluation value, or the comprehensive evaluation value formed by the first evaluation value and the second evaluation value is used as the screening index for the main datum positioning points.
[0035] The coordinates of the three vertices of the triangle corresponding to the largest first evaluation value, the largest second evaluation value, or the maximum value among the comprehensive evaluation values formed by the first and second evaluation values are used as the three main reference positioning points.
[0036] In some embodiments, the geometric center of a triangle is used as the marker point of the triangle, and the geometric center of each triangle is projected onto the maximum functional surface to obtain a first projection point.
[0037] In some embodiments, when the first evaluation value is used as the screening index, all triangles are traversed to obtain the largest first evaluation value and the corresponding triangle vertex coordinates. If only one set of triangle vertex coordinates has the largest first evaluation value, then that set of vertex coordinates is used as the main reference positioning point, and the second evaluation value is not calculated. If there are multiple sets of triangle vertex coordinates corresponding to the largest first evaluation value, then the second evaluation value is calculated for each set of triangles. The first evaluation value and the second evaluation value of each set of triangles form a comprehensive evaluation value, and the triangle vertex coordinates corresponding to the optimal comprehensive evaluation value are used as the main reference positioning point.
[0038] In some embodiments, when the second evaluation value is used as the screening index, all triangles are traversed to obtain the largest second evaluation value and the corresponding triangle vertex coordinates. If only one set of triangle vertex coordinates has the largest second evaluation value, then that set of vertex coordinates is used as the main reference positioning point, and the first evaluation value is not calculated. If there are multiple sets of triangle vertex coordinates corresponding to the largest second evaluation value, then the first evaluation value is calculated for each set of triangles, and the first evaluation value and the second evaluation value of each set of triangles are used to form a comprehensive evaluation value. The triangle vertex coordinates corresponding to the optimal comprehensive evaluation value are used as the main reference positioning point.
[0039] In some embodiments, all triangles are traversed, and a first evaluation value and a second evaluation value are calculated respectively. The comprehensive evaluation value is obtained by weighting the first evaluation value and the second evaluation value, and the vertex of the triangle corresponding to the maximum comprehensive evaluation value is taken as the main reference positioning point. If the maximum or minimum comprehensive evaluation value corresponds to multiple triangles, the weights of the first evaluation value and the second evaluation value are reset, and the comprehensive evaluation value is recalculated until a unique triangle corresponding to the maximum or minimum comprehensive evaluation value is obtained, and the main reference positioning point is obtained.
[0040] In some embodiments, the coordinates of all candidate points for the main reference positioning of the target workpiece are known. The candidate points are clustered using a clustering algorithm, and the clustered candidate points form at least 3 independent regions. The candidate points in each independent region form a candidate point set.
[0041] Example 1
[0042] An automated screening method for rigid workpiece references comprises the following steps:
[0043] S1. The coordinates of all candidate points for the main datum positioning of the target workpiece are known. The candidate points are clustered using a clustering algorithm, and the clustered candidate points form at least 3 independent regions; the candidate points in each independent region form a candidate point set.
[0044] S2. Randomly select three candidate point sets, select one point from each candidate point set, and form a triangle with the three points. Iterate through all triangle combinations and obtain the geometric center of each triangle.
[0045] S3. Traverse all functional surfaces of the target workpiece, find the functional surface with the largest area, called the maximum functional surface; obtain the centroid of the target workpiece, and project the centroid onto the maximum functional surface to obtain the centroid projection point; the order of S2 and S3 can be interchanged;
[0046] S4. Project the geometric center of each triangle obtained in S2 onto the maximum functional surface to obtain the first projection point. The distance between the first projection point and the centroid projection point is used as the first evaluation value. And, or, project each triangle obtained in S2 onto the maximum functional surface to obtain the triangle projection area. Use the triangle projection area as the second evaluation value.
[0047] S5. Find the maximum first evaluation value and its corresponding triangle. If there is only one triangle, then the three vertices of the triangle are used as three main reference positioning points. If there are multiple triangles corresponding to the maximum first evaluation value, then calculate the second evaluation value for these triangles, take the maximum comprehensive value of the first evaluation value and the second evaluation value, and use the vertex of the triangle corresponding to the maximum comprehensive value as three main reference positioning points.
[0048] Example 2
[0049] The difference between this embodiment and embodiment 1 is that S5 is replaced by: finding the maximum second evaluation value and its corresponding triangle. If there is only one triangle, the three vertices of the triangle are used as three main reference positioning points. If there are multiple triangles corresponding to the maximum second evaluation value, the first evaluation value is calculated for these triangles, and the maximum comprehensive value of the first evaluation value and the second evaluation value is taken. The vertex of the triangle corresponding to the maximum comprehensive value is used as three main reference positioning points.
[0050] Example 3
[0051] The difference between this embodiment and embodiment 1 is that S5 is replaced by: calculating the first evaluation value and the second evaluation value of each triangle, weighting the first evaluation value and the second evaluation value to obtain the comprehensive evaluation value, and taking the vertex of the triangle corresponding to the maximum comprehensive evaluation value as the main reference positioning point.
[0052] The above specific implementation examples are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.
Claims
1. An automated screening method for rigid workpiece datums, comprising screening the main datum positioning points of the target workpiece; characterized in that: The goal of master datum screening is to determine three master datum positioning points. Before master datum screening, all candidate master datum positioning points of the target workpiece and the centroid of the target workpiece are known. Traverse all functional surfaces of the target workpiece and find the functional surface with the largest area, which is called the maximum functional surface; Obtain the centroid projection point of the target workpiece's centroid onto the maximum functional surface; Make the candidate points of the main reference positioning form mutually independent regions, each region corresponds to a candidate point set, and the number of candidate point sets is ≥3; select any three coordinate points, and the three coordinate points come from different candidate point sets; traverse all triangles and obtain the marker point of each triangle according to the same rules, and obtain the first projection point by projecting the marker point onto the maximum functional surface, and use the distance between the first projection point and the centroid projection point as the first evaluation value. The area formed by the three coordinate points is used as the second evaluation value; the first evaluation value, or the second evaluation value, or the comprehensive evaluation value formed by the first and second evaluation values is used as the screening index for the main benchmark positioning point; The automated screening method is performed according to the following steps: S1. The coordinates of all candidate points for the main datum positioning of the target workpiece are known. The candidate points are clustered using a clustering algorithm, and the clustered candidate points form at least 3 independent regions; the candidate points in each independent region form a candidate point set. S2. Randomly select three candidate point sets, select one point from each candidate point set, and form a triangle with the three points. Iterate through all triangle combinations and obtain the geometric center of each triangle. S3. Traverse all functional surfaces of the target workpiece and find the functional surface with the largest area, which is called the maximum functional surface; Obtain the centroid of the target workpiece and project it onto the maximum functional surface to obtain the centroid projection point; the order of S2 and S3 can be interchanged; S4. Project the geometric center of each triangle obtained in S2 onto the maximum functional surface to obtain the first projection point. The distance between the first projection point and the centroid projection point is used as the first evaluation value. Alternatively, each triangle obtained in S2 is projected onto the maximum functional surface to obtain the triangle projection area, which is then used as the second evaluation value. S5. Find the maximum first evaluation value and its corresponding triangle. If there is only one triangle, then the three vertices of the triangle are used as three main reference positioning points. If there are multiple triangles corresponding to the maximum first evaluation value, then calculate the second evaluation value for these triangles, take the maximum comprehensive value of the first evaluation value and the second evaluation value, and use the vertex of the triangle corresponding to the maximum comprehensive value as three main reference positioning points. Alternatively, S5 can be replaced with: Find the maximum second evaluation value and its corresponding triangle. If there is only one triangle, then the three vertices of the triangle are used as three main reference points. If there are multiple triangles corresponding to the maximum second evaluation value, then calculate the first evaluation value for these triangles, take the maximum combined value of the first evaluation value and the second evaluation value, and use the vertex of the triangle corresponding to the maximum combined value as three main reference points. Alternatively, S5 can be replaced with: Calculate the first and second evaluation values for each triangle, calculate the comprehensive evaluation value by weighting the first and second evaluation values, and take the vertex of the triangle with the largest comprehensive evaluation value as the main reference positioning point.
2. The automated screening method for rigid workpiece references as described in claim 1, characterized in that: The first evaluation value is obtained in the following ways: First, three coordinate points form a triangle; then, each triangle is projected onto the maximum functional surface, and the area of the projected triangle onto the maximum functional surface is used as the second evaluation value. Alternatively, the first evaluation value is obtained as follows: three coordinate points form a triangle, and the area of each triangle is used as the second evaluation value. Alternatively, three coordinate points are projected onto the maximum functional surface, and the area of the circle (circumcircle) containing the three coordinate points is used as the second evaluation value. Alternatively, three coordinate points are projected onto the maximum functional surface, and the projection points of the three coordinate points on the maximum functional surface form a projection triangle, and the area of the inscribed circle of the projection triangle is used as the second evaluation value. Alternatively, the first evaluation value is obtained as the ratio of the areas of the inscribed circle and the circumcircle as the second evaluation value. Alternatively, the first evaluation value is obtained as the ratio of the areas of the circumcircle and the projection triangle as the second evaluation value. Alternatively, the first evaluation value is obtained as the ratio of the areas of the inscribed circle and the projection triangle as the second evaluation value.
3. The automated screening method for rigid workpiece references as described in claim 1 or 2, characterized in that: The second evaluation value is obtained by: traversing all triangles and obtaining the marker point of each triangle according to the same rules, projecting the marker point onto the maximum functional surface to obtain the first projection point, and calculating the distance between the first projection point and the centroid projection point; or, the second evaluation value is obtained by: traversing all coordinate sets composed of three points, obtaining the circumcircle of the three points, and calculating the center of the circle, and the distance between the center of the circumcircle and the centroid of the triangle.
4. The automated screening method for rigid workpiece references as described in claim 1, characterized in that: The coordinates of the three vertices of the triangle corresponding to the largest first evaluation value, the largest second evaluation value, or the maximum value among the comprehensive evaluation values formed by the first and second evaluation values are used as the three main reference positioning points.
5. The automated screening method for rigid workpiece references as described in claim 1, characterized in that: Using the geometric center of a triangle as its landmark, the first projection point is obtained by projecting the geometric center of each triangle onto the maximum functional surface.
6. The automated screening method for rigid workpiece references as described in claim 1 or 2, characterized in that: When using the first evaluation value as the screening criterion, all triangles are traversed to obtain the largest first evaluation value and the corresponding triangle vertex coordinates. If only one set of triangle vertex coordinates has the largest first evaluation value, then that set of vertex coordinates is used as the main reference positioning point, and the second evaluation value is not calculated. If there are multiple sets of triangle vertex coordinates corresponding to the largest first evaluation value, then the second evaluation value is calculated for each set of triangles. The first evaluation value and the second evaluation value of each set of triangles are combined to form a comprehensive evaluation value. The triangle vertex coordinates corresponding to the optimal comprehensive evaluation value are used as the main reference positioning point.
7. The automated screening method for rigid workpiece references as described in claim 1, characterized in that: When using the second evaluation value as the screening criterion, all triangles are traversed to obtain the largest second evaluation value and the corresponding triangle vertex coordinates. If only one set of triangle vertex coordinates has the largest second evaluation value, then that set of vertex coordinates is used as the main reference positioning point, and the first evaluation value is not calculated. If the maximum second evaluation value corresponds to multiple sets of triangle vertex coordinates, then the first evaluation value is calculated for each set of triangles. The first and second evaluation values of each set of triangles form a comprehensive evaluation value, and the triangle vertex coordinates corresponding to the optimal comprehensive evaluation value are used as the main reference positioning point.
8. The automated screening method for rigid workpiece references as described in claim 1, characterized in that: Traverse all triangles, calculate the first evaluation value and the second evaluation value respectively, and calculate the comprehensive evaluation value by weighting the first evaluation value and the second evaluation value. Take the vertex of the triangle corresponding to the maximum comprehensive evaluation value as the main reference positioning point. If the maximum or minimum comprehensive evaluation value corresponds to multiple triangles, reset the weight of the first evaluation value and the second evaluation value, recalculate the comprehensive evaluation value, until a unique triangle corresponding to the maximum or minimum comprehensive evaluation value is obtained, and obtain the main reference positioning point.