Calculation method and system for pressing rivet center positioning workpiece

Abstract

The invention provides a calculation method and system for a press riveting center positioning workpiece, and the system comprises a data obtaining module which obtains the coordinates of a positioning mark point on a plane drawing and the actual coordinates of the mark point on a machine; the vector generation module is used for generating a two-dimensional position vector; the angle comparison module is used for comparing angle changes; the coordinate rotating module is used for rotating all coordinates in the drawing coordinate system according to the angle change so as to match the direction of the machine coordinate system; the translation calculation module is used for calculating the translation amount according to the rotated drawing coordinates and machine coordinates; the transformation matrix construction module is used for constructing a rigid transformation matrix in combination with rotation and translation information; and the coordinate conversion module is used for converting coordinates of other points on the drawing into coordinates under a machine coordinate system. According to the method, the conversion relation from the drawing coordinates to the machine coordinates is obtained through a geometric method, strict requirements about matrix attributes in linear algebra do not need to be met, the situation that only two mark points exist can be processed, and the angle change of the workpiece can be directly obtained.

Description

Technical Field

[0001] The invention relates to the technical field of press riveting center positioning workpiece, and in particular to a calculation method and system for press riveting center positioning workpiece. Background Art

[0002] In modern manufacturing, riveting is a common connection process used to fix two or more sheet metal parts together. In order to ensure the quality and accuracy of riveting, the positioning of the workpiece is a very critical step; the traditional riveting process often requires manual placement and positioning of the workpiece, which is not only time-consuming and labor-intensive, but also prone to human errors, affecting the quality of the final product. With the development of automation technology, automated riveting center machines are gradually being adopted. These machines realize riveting automation by importing workpiece drawings and automatically finding the working position of the workpiece.

[0003] In the prior art, the riveting center machine usually uses the linear algebra transformation method to determine the conversion relationship between the drawing coordinates and the machine coordinates; this method calculates the transformation matrix based on the mark points (usually the hole positions) on the drawing, so that the positions of other feature points on the drawing can be converted to the positions in the machine coordinate system to guide the machine to perform precise operations. However, this linear algebra-based method has some limitations and shortcomings.

[0004] Deficiencies of existing technology: 1. Strict requirements on data: Existing methods rely on matrix operations in linear algebra, requiring the matrices used to satisfy certain mathematical properties, such as full rank and positive definiteness. If these conditions are not met, for example, when the three mark points on the drawing are on a straight line, this method cannot be used to calculate the transformation relationship.

[0005] 2. Limited scope of application: Due to the above-mentioned data requirements, existing technologies are difficult to apply in some cases, especially when the number of mark points is small or the distribution is not ideal. For example, when there are only two mark points, traditional methods may not provide enough information for accurate positioning.

[0006] 3. Lack of flexibility: Existing methods have poor adaptability to changes in input data. Once an unexpected situation occurs (such as collinear marks), additional manual intervention or adjustment is required, which reduces the degree of automation of the system.

[0007] 4. High complexity: Linear algebra-based methods involve complex mathematical operations, which not only increase the complexity of calculations, but may also cause the system response time to become longer, affecting production efficiency.

[0008] Therefore, the prior art has deficiencies and needs further improvement. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a calculation method and system for positioning a workpiece by a riveting center.

[0010] To achieve the above object, the specific scheme of the present invention is as follows: The present invention provides a computing system for positioning a workpiece at a press riveting center, the system comprising: A data acquisition module, used to acquire the coordinates of at least three positioning mark points on the plane drawing of the sheet metal workpiece and the actual coordinates of the mark points on the machine; The vector generation module is used to generate the corresponding two-dimensional position vector according to the coordinates of the mark points on the drawing and the machine; An angle comparison module for comparing the drawing coordinate vector with the machine coordinate vector to determine the angular change of the workpiece; A coordinate rotation module is used to rotate all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change; A translation calculation module is used to calculate the translation amount according to the rotated drawing coordinates and machine coordinates; Transformation matrix construction module, used to construct a rigid transformation matrix by combining rotation and translation information; The coordinate conversion module is used to convert the coordinates of other points on the drawing into coordinates in the machine coordinate system using the rigid transformation matrix.

[0011] Furthermore, the system also includes a visual detection device, which is used to automatically capture and obtain the actual coordinates of the mark points of the workpiece on the mobile platform of the machine.

[0012] Furthermore, the data acquisition module can also handle the situation where there are only two mark points, and thereby achieve accurate positioning of the workpiece.

[0013] Furthermore, the coordinate conversion module is used to output the converted coordinate data to the riveting equipment after completing the coordinate conversion, so as to facilitate subsequent processing operations.

[0014] Further, the system includes a user interface that allows an operator to input parameters, monitor the process, and receive system feedback.

[0015] The present invention also provides a method for calculating the center positioning of a workpiece by riveting. Based on the above-mentioned calculation system, the method comprises the following steps: S1, obtaining at least three positioning mark points and their coordinates on the plane drawing of the sheet metal workpiece; S2, obtaining the actual coordinates of the mark point on the machine; S3, generating a corresponding two-dimensional position vector according to the coordinates of the mark points on the drawing and the machine; S4, comparing the drawing coordinate vector with the machine coordinate vector to determine the angular change of the workpiece; S5, rotating all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change; S6, calculating the translation amount between the rotated drawing coordinates and the machine coordinates; S7, constructing a rigid transformation matrix by combining rotation and translation information; S8, using the rigid transformation matrix to convert the coordinates of other points on the drawing into coordinates in the machine coordinate system.

[0016] Furthermore, in step S2, when obtaining the actual coordinates of the mark point, the position of the mark point on the workpiece is automatically detected by camera vision or other non-contact measurement technology.

[0017] Furthermore, the method can handle the situation where there are only two mark points, and calculate the accurate position of the workpiece accordingly.

[0018] Furthermore, the method further includes a verification step S9 for verifying whether the converted coordinates meet preset accuracy requirements.

[0019] Furthermore, the method further includes a step S10 of transmitting the converted coordinate data to a riveting device so as to perform a precise riveting operation.

[0020] The technical solution of the present invention has the following beneficial effects: 1. Reduce the requirements on matrix properties: Traditional linear algebra transformation methods need to meet certain strict mathematical conditions, such as full rank and positive definiteness of the matrix, etc. The method of the present invention does not require these restrictions, so it can work normally even when the mark points are collinear, thereby improving the applicability and robustness of the system.

[0021] 2. Support fewer mark points: Traditional methods usually require at least three non-collinear mark points for positioning. However, the method of the present invention can achieve accurate positioning with only two mark points, which greatly reduces the requirements for workpiece drawing information and increases application flexibility.

[0022] 3. Directly obtain angle changes: By comparing the angles of the drawing coordinate vector and the machine coordinate vector, the present invention can directly calculate the angular change of the workpiece from the drawing position to the machine position. This ability to directly obtain the angle helps to simplify subsequent rotation and translation calculations.

[0023] 4. Simplify the algorithm process: Compared with complex linear algebraic operations, the present invention adopts a geometric method to simplify the calculation process of the conversion relationship, which not only reduces the calculation complexity, but also speeds up the response time of the system and improves production efficiency.

[0024] 5. Improve positioning accuracy: Through precise geometric calculation and application of rigid transformation matrix, the present invention can provide high-precision workpiece positioning, ensure the accuracy of riveting operation, and thus improve the quality of the final product.

[0025] 6. Enhanced automation: Since the method of the present invention can automatically process the mark point data in various situations, the need for manual intervention is reduced, the automation level of the riveting center machine is further enhanced, and the labor cost is reduced.

[0026] 7. Wide applicability: The technology of the present invention is not only applicable to standard three-hole positioning, but also to the case of only two mark points, and can even be extended to other similar application scenarios, with high versatility and adaptability.

[0027] 8. Easy to implement and integrate: The method of the present invention is based on intuitive geometric principles and is easy to understand and implement. In addition, it can be easily integrated into existing press riveting automation equipment without major modifications to existing hardware.

[0028] 9. Improve production efficiency: By reducing manual intervention, simplifying the calculation process and improving positioning accuracy, the present invention can significantly improve the efficiency of the entire production process, shorten the production cycle and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of a drawing of the present invention; Figure 2 It is a schematic diagram of the coordinate vector of the drawing of the present invention; Figure 3 is a schematic diagram of machine coordinate vectors of the present invention; Figure 4 It is a schematic diagram of the rotation amount calculation of the present invention; Figure 5 It is a schematic diagram of calculating the rotation and translation amount of the present invention; Figure 6 It is a schematic diagram of calculating displacement translation of the present invention; Figure 7 It is the overall flow chart of the present invention. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments; it can be understood that the specific embodiments described herein are only used to explain the present invention rather than to limit the present invention; it should also be noted that, for ease of description, only the parts related to the present invention rather than all are shown in the accompanying drawings.

[0031] Combination Figure 1-Figure 7 As shown, the present invention provides a computing system for positioning a workpiece by a riveting center, the system comprising: A data acquisition module, used to acquire the coordinates of at least three positioning mark points on the plane drawing of the sheet metal workpiece and the actual coordinates of the mark points on the machine; The vector generation module is used to generate the corresponding two-dimensional position vector according to the coordinates of the mark points on the drawing and the machine; An angle comparison module for comparing the drawing coordinate vector with the machine coordinate vector to determine the angular change of the workpiece; A coordinate rotation module is used to rotate all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change; A translation calculation module is used to calculate the translation amount according to the rotated drawing coordinates and machine coordinates; Transformation matrix construction module, used to construct a rigid transformation matrix by combining rotation and translation information; The coordinate conversion module is used to convert the coordinates of other points on the drawing into coordinates in the machine coordinate system using the rigid transformation matrix.

[0032] The system also includes a visual detection device, which is used to automatically capture and obtain the actual coordinates of the mark points of the workpiece on the machine moving platform.

[0033] The data acquisition module can also handle the situation where there are only two mark points, and accordingly achieve accurate positioning of the workpiece.

[0034] The coordinate conversion module is used to output the converted coordinate data to the riveting equipment after completing the coordinate conversion, so as to facilitate subsequent processing operations.

[0035] The system also includes a user interface that allows an operator to input parameters, monitor the process, and receive system feedback.

[0036] The present invention also provides a method for calculating the center positioning of a workpiece by riveting, based on the above-mentioned calculation system, characterized in that the method comprises the following steps: S1, obtaining at least three positioning mark points and their coordinates on the plane drawing of the sheet metal workpiece; S2, obtaining the actual coordinates of the mark point on the machine; S3, generating a corresponding two-dimensional position vector according to the coordinates of the mark points on the drawing and the machine; S4, comparing the drawing coordinate vector with the machine coordinate vector to determine the angular change of the workpiece; S5, rotating all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change; S6, calculating the translation amount between the rotated drawing coordinates and the machine coordinates; S7, constructing a rigid transformation matrix by combining rotation and translation information; S8, using the rigid transformation matrix to convert the coordinates of other points on the drawing into coordinates in the machine coordinate system.

[0037] In step S2, when obtaining the actual coordinates of the mark point, the position of the mark point on the workpiece is automatically detected by camera vision or other non-contact measurement technology.

[0038] This method can also handle the situation where there are only two mark points and calculate the exact position of the workpiece based on them.

[0039] The method further includes a verification step S9 for verifying whether the converted coordinates meet the preset accuracy requirements.

[0040] The method further comprises a step S10 of transmitting the converted coordinate data to a riveting device so as to perform a precise riveting operation.

[0041] Working principle of the present invention: The present invention proposes a method and system for calculating the positioning of a workpiece by a geometric method. The method and system are intended to achieve automatic conversion from drawing coordinates to machine coordinates, thereby guiding the precise positioning of the press riveting center machine. The following is a detailed working principle: 1. Get drawing information Steps: First, obtain the plane drawing information of the sheet metal workpiece, including at least three mark points (usually hole positions) used for positioning and their coordinates on the drawing.

[0042] Purpose: These mark points will be used as reference points for subsequent coordinate transformation calculations.

[0043] 2. Generate drawing coordinate vector Steps: Based on the coordinates of the mark points on the drawing, make a difference between them to get the two-dimensional position vector between each mark point and other mark points.

[0044] Purpose: These vectors represent the relative position relationship between the mark points and provide basic data for subsequent angle comparison.

[0045] 3. Get the actual coordinates Steps: Place the workpiece on the mobile platform of the machine, detect and obtain the actual machine coordinates of the mark points on the workpiece through camera vision or other means.

[0046] Purpose: Actual coordinates are the basis of machine operation and are used for comparison and conversion with drawing coordinates.

[0047] 4. Generate machine coordinate vector Steps: Similarly, based on the actual acquired mark point coordinates, generate a two-dimensional position vector between each mark point and other mark points.

[0048] Purpose: These vectors are used to compare with the drawing coordinate vectors to determine the angular change of the workpiece.

[0049] 5. Compare angle changes Steps: Compare the angles of the drawing coordinate vector and the machine coordinate vector to determine the angular change of the workpiece from the drawing position to the machine position.

[0050] Purpose: By comparing the angles, we can know how the workpiece rotates during placement, which is a key step in building a rigid transformation matrix.

[0051] 6. Rotate the drawing coordinates Steps: Based on the angle change obtained in step 5, rotate all coordinates in the drawing coordinate system around the coordinate origin to match the direction of the machine coordinate system.

[0052] Purpose: The coordinates of the rotated drawing are consistent with the direction of the machine coordinate system, preparing for the next translation calculation.

[0053] 7. Calculate the translation Steps: Compare the rotated drawing coordinates with the actual machine coordinates, and calculate the displacement required after the rotation, that is, the translation.

[0054] Purpose: By calculating the translation, the exact position of the workpiece in the machine coordinate system can be determined.

[0055] 8. Constructing the rigid transformation matrix Steps: Combine the information of rotation and translation to construct a rigid transformation matrix. This matrix can be used to transform the coordinates of other points on the drawing to the coordinates of the machine coordinate system.

[0056] Purpose: The rigid transformation matrix is ​​the core of the entire positioning process, which ensures that all points on the drawing can be accurately converted to the machine coordinate system.

[0057] 9. Applying the Transformation Matrix Steps: Use the constructed rigid transformation matrix to transform the coordinates of other points on the drawing to obtain the exact positions of these points in the machine coordinate system.

[0058] Purpose: The converted coordinates can be directly used to guide the riveting equipment to perform precise processing operations.

[0059] Summarize The present invention avoids the strict requirements of traditional linear algebra methods on matrix properties (such as full rank, positive definite, etc.) through geometric methods, especially through vector calculation and angle comparison. This method not only simplifies the calculation process and improves the flexibility and reliability of the system, but also can achieve accurate positioning when there are only two mark points. Finally, by constructing a rigid transformation matrix, efficient and accurate conversion from drawing coordinates to machine coordinates is achieved, thereby improving the performance and efficiency of the riveting automation equipment.

[0060] Embodiment 1: The riveting center machine (hereinafter referred to as the machine) can realize riveting automation by automatically finding the working position of the workpiece without manual work. When the machine realizes this function, it needs to import the drawing of the workpiece. The drawing needs to mark more than three holes for positioning, which are called mark points. In actual production, the workpiece is placed on the mobile platform of the machine, and the position of the workpiece mark point is obtained through camera vision or other means. The obtained machine coordinates are compared with the coordinates in the drawing, so as to calculate the conversion relationship from the drawing coordinates to the machine coordinates, and the machine coordinates of the holes on other drawings can be calculated, so as to realize the positioning function. Most existing machines use the method of solving linear algebraic transformation to obtain this conversion relationship. This method needs to satisfy some properties of linear matrix to be used, such as full rank and positive definite. For example, it cannot be used when there are three mark points on a straight line.

[0061] The method of obtaining the above transformation relationship by geometric method is divided into the following main steps: 1. Get the plane drawing information of the sheet metal workpiece, including the coordinates of the workpiece's mark points in the drawing.

[0062] Drawing diagram: As shown in Figure 1, three mark points (hole positions) for positioning are marked. The coordinate system on the drawing is usually the reference coordinate system used during design.

[0063] 2. Subtract the coordinates of the mark points in the drawing from each other to obtain the two-dimensional position vector of each mark point and other mark points. Figure 2 The relative position vectors between the mark points selected on the drawing are shown. For example, if three points A, B, and C are selected, vectors AB, AC, BA, etc. are displayed; 3. After obtaining the machine coordinates of the workpiece's mark points on the machine, subtract the coordinates of the mark points in pairs to obtain the two-dimensional position vector of each mark point and other mark points. The machine coordinate vector diagram is as follows: Figure 3 shown.

[0064] 4. Compare the two obtained angles to get the angle change from the drawing position to the machine position of the workpiece. Figure 4 The figure shows a schematic diagram of the rotation calculation.

[0065] 5. With the coordinate origin as the center, rotate the drawing coordinates and calculate the coordinate changes caused by the rotation. Figure 5 As shown, this is a schematic diagram for calculating the rotation and translation.

[0066] 6. Compare the machine coordinates of the workpiece with the coordinates obtained in step 5 to obtain the coordinate changes caused by the displacement. Figure 6 As shown in FIG. 1 , a schematic diagram of calculating the displacement translation is shown in FIG.

[0067] 7. Combining the rotation change in step 5 and the translation change in step 6, we get the rigid change matrix from drawing coordinates to machine coordinates. The following is the two-dimensional rigid transformation matrix model:

[0068] The method: 1. It can avoid some matrix property conditions that must be satisfied by linear algebra methods, such as full rank and positive definite.

[0069] 2. The angle of the workpiece can be obtained.

[0070] 3. Two mark points can also be calculated.

[0071] 1. The geometric method is used to achieve the goal of positioning the workpiece in the riveting center machine.

[0072] 2. The specific method is: the coordinates of the points are used to obtain the relative position vector between the points to obtain the rotation angle. After obtaining the rotation angle, the rigid transformation matrix from the drawing coordinates to the machine coordinates is obtained by calculating the rotation translation and displacement translation, so as to locate other points of the workpiece.

[0073] Comparison of calculation example and result. The calculation result is consistent with the meas measurement value: The code is as follows: / / The first reference case data.ref1.x = 0; data.ref1.y = 0; data.ref2.x = 500; data.ref2.y = 0; data.ref3.x = 0; data.ref3.y = 400; / / IV. Rotate 150° clockwise around the origin, then move 30 units to the right along the x-axis and 50 units down along the y-axis data.meas1.x = 0 + 30; data.meas1.y = 0 - 50; data.meas2.x = -433.0127 + 30; data.meas2.y = 250 - 50; data.meas3.x = -200 + 30; data.meas3.y = -346.4102 - 50; double angle = Radian2degree(CalcTheta3Marks(&data)); printf("theta = %f\n", angle); ret = CalcCoord3Marks(&data,&data.ref1); printf("calculated x1 = %f, calculated y1 = %f\n", ret.x, ret.y); ret = CalcCoord3Marks(&data,&data.ref2); printf("calculated x2 = %f, calculated y2 = %f\n", ret.x, ret.y); ret = CalcCoord3Marks(&data,&data.ref3); printf("calculated x3 = %f, calculated y3 = %f\n", ret.x, ret.y); Result output: theta = 150.000000 calculated x1 = 30.000000, calculated y1 = -50.000011 calculated x2 = -403.012703, calculated y2 = 199.999986 calculated x3 = -169.999997, calculated y3 = -396.410174 Specific embodiment 2: (three mark points) The present invention relates to a method and system for calculating the center of a press riveting workpiece by a geometric method, which can automatically convert the coordinates on a drawing into machine coordinates, thereby guiding the press riveting equipment to perform precise positioning. The following is a specific implementation case.

[0074] In this example, we will use a sheet metal workpiece with three holes (as mark points), and there are certain rotation and translation deviations between the drawing of the workpiece and the actual position placed on the riveting machine. Our goal is to accurately determine the positions of these holes in the machine tool coordinate system through the method of the present invention.

[0075] Steps Get drawing information Suppose we have three hole marking points A, B, and C, and their coordinates on the drawing are (0, 0), (100,0), and (50, 86.6), respectively, in millimeters.

[0076] Generate drawing coordinate vector Calculate vector AB: (100-0, 0-0) = (100, 0) Calculate the vector AC: (50-0, 86.6-0) = (50, 86.6) Get actual coordinates Use the visual inspection system to obtain the actual coordinates of the holes on the workpiece. Assume that the actual coordinates of holes A', B', and C' are (10, 20), (110, 20), and (60, 106.6), respectively.

[0077] Generate machine coordinate vector Calculate vector A'B': (110-10, 20-20) = (100, 0) Calculate vector A'C': (60-10, 106.6-20) = (50, 86.6) Compare angle changes Comparing the angles of the drawing vector AB and the machine vector A'B', we find that they are in the same direction, indicating that no rotation around the origin has occurred.

[0078] Likewise, compare the angles of the drawing vector AC and the machine vector A'C' to confirm that there is no additional rotation.

[0079] Rotate drawing coordinates Since no rotation is detected, the drawing coordinates do not need to be rotated.

[0080] Calculate the translation The translation amount is the change of hole position A from the drawing coordinate (0, 0) to the actual coordinate (10, 20): ΔX=10mm, ΔY=20mm.

[0081] Constructing a rigid transformation matrix Since there is no rotation, the transformation matrix simplifies to just the translation component: Dark version T = [1, 0, 10; 0, 1, 20; 0, 0, 1] Applying a transformation matrix For any point P(x, y) on the drawing, its new coordinates P'(x', y') in the machine coordinate system can be obtained by: Dark version P' = T * P = [1, 0, 10; 0, 1, 20; 0, 0, 1] * [x; y; 1] = [x + 10; y + 20; 1] Therefore, the new coordinates P' of any point P on the drawing are its original coordinates plus a fixed offset (10, 20).

[0082] Verification Through the above steps, we have successfully converted the drawing coordinates into machine coordinates, and can be used for subsequent riveting operations. To verify the accuracy of the results, we can perform the same transformation process on other points with known coordinates and check whether the converted coordinates are consistent with the actual measured values. If all points are consistent with expectations, the effectiveness and reliability of this method are proven.

[0083] This specific embodiment demonstrates how to use the technology in the present invention to achieve the conversion from drawing coordinates to machine coordinates, ensuring precise positioning in the riveting process.

[0084] Specific embodiment 3 (two mark points) The present invention proposes a method and system for calculating the center positioning of a workpiece by a geometric method. In this embodiment, we will explain in detail how to use this method to process a sheet metal workpiece with two mark points, and these mark points are rotated and translated when actually placed.

[0085] Assume that we have a sheet metal workpiece with two holes (as mark points), and there is a certain rotation and translation deviation between the drawing of the workpiece and the actual position of the workpiece placed on the riveting machine. Our goal is to accurately determine the positions of these holes in the machine tool coordinate system through the method of the present invention.

[0086] Steps Get drawing information Assume that we have two hole marking points A and B, whose coordinates on the drawing are (0, 0) and (100, 0) respectively, in millimeters.

[0087] Generate drawing coordinate vector Calculate vector AB: (100-0, 0-0) = (100, 0) Get actual coordinates Use the visual inspection system to obtain the actual coordinates of the holes on the workpiece. Assume that the actual coordinates of holes A' and B' are (20, 30) and (100, 90) respectively.

[0088] Generate machine coordinate vector Calculate vector A'B': (100-20, 90-30) = (80, 60) Compare angle changes Calculate the angle change between vector AB and vector A'B'.

[0089] The direction angle of vector AB is θ_AB = atan2(0, 100) = 0° The direction angle of vector A'B' is θ_A'B' = atan2(60, 80) ≈ 36.87° Angle change Δθ = θ_A'B' - θ_AB = 36.87° Rotate drawing coordinates Rotate all coordinates in the drawing coordinate system according to the angle change Δθ.

[0090] Rotation matrix R: Dark version R = [cos(Δθ), -sin(Δθ); sin(Δθ), cos(Δθ)] = [cos(36.87°), -sin(36.87°); sin(36.87°), cos(36.87°)] ≈ [0.8, -0.6; 0.6, 0.8] Rotate points A(0, 0) and B(100, 0) on the drawing: A' = R * [0; 0] = [0; 0] B' = R * [100; 0] = [80; 60] Calculate the translation Compare the rotated drawing coordinates with the actual machine coordinates and calculate the translation amount.

[0091] Translation ΔX = 20 - 0 = 20 mm Translation ΔY = 30 - 0 = 30mm Constructing a rigid transformation matrix Combining the information of rotation and translation, construct the rigid transformation matrix T: Dark version T = [cos(Δθ), -sin(Δθ), ΔX; sin(Δθ), cos(Δθ), ΔY; 0, 0, 1] ≈ [0.8, -0.6, 20; 0.6, 0.8, 30; 0, 0, 1] Applying a transformation matrix For any point P(x, y) on the drawing, its new coordinates P'(x', y') in the machine coordinate system can be obtained by: Dark version P' = T * P = [0.8, -0.6, 20; 0.6, 0.8, 30; 0, 0, 1] * [x; y; 1] = [0.8 * x - 0.6 * y + 20; 0.6 * x + 0.8 * y + 30; 1] Therefore, the new coordinates P' of any point P on the drawing are its coordinates after rotation and translation.

[0092] Verification To verify the accuracy of the result, we can perform the same transformation process on other points with known coordinates and check whether the transformed coordinates are consistent with the actual measured values. For example, assuming there is another point C(50, 0) on the drawing, we can calculate its position in the machine coordinate system: C' = T * [50; 0; 1] = [0.8 * 50 - 0.6 * 0 + 20; 0.6 * 50 + 0.8 * 0 + 30; 1] = [60; 60; 1] Check whether the coordinates of C' are consistent with the actual measured values. If they are consistent, the validity and reliability of the method are proved.

[0093] This specific embodiment demonstrates how to use the technology of the present invention to handle the situation with only two mark points, and can accurately calculate the rotation and translation, thereby ensuring precise positioning in the riveting process.

[0094] The above description is only a preferred embodiment of the present invention, and does not limit the scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the protection scope of the present invention.

Claims

1. A calculation system for positioning a workpiece by a riveting center, characterized in that: The system includes: A data acquisition module, used to acquire the coordinates of at least three positioning mark points on the plane drawing of the sheet metal workpiece and the actual coordinates of the mark points on the machine; The vector generation module is used to generate the corresponding two-dimensional position vector according to the coordinates of the mark points on the drawing and the machine; An angle comparison module for comparing the drawing coordinate vector with the machine coordinate vector to determine the angular change of the workpiece; A coordinate rotation module is used to rotate all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change; A translation calculation module is used to calculate the translation amount according to the rotated drawing coordinates and machine coordinates; Transformation matrix construction module, used to construct a rigid transformation matrix by combining rotation and translation information; The coordinate conversion module is used to convert the coordinates of other points on the drawing into coordinates in the machine coordinate system using the rigid transformation matrix.

2. The computing system for positioning a workpiece by a riveting center as claimed in claim 1, characterized in that: The system also includes a visual detection device, which is used to automatically capture and obtain the actual coordinates of the mark points of the workpiece on the machine moving platform.

3. The calculation system for positioning a workpiece by a riveting center according to claim 1 or 2, characterized in that: The data acquisition module can also handle the situation where there are only two mark points, and accordingly achieve accurate positioning of the workpiece.

4. The computing system for positioning a workpiece by a riveting center as claimed in claim 1, characterized in that: The coordinate conversion module is used to output the converted coordinate data to the riveting equipment after completing the coordinate conversion, so as to facilitate subsequent processing operations.

5. The computing system for positioning a workpiece by a riveting center as claimed in claim 1, characterized in that: The system also includes a user interface that allows an operator to input parameters, monitor the process, and receive system feedback.

6. A method for calculating the center positioning of a workpiece by riveting, based on the calculation system according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: S1, obtaining at least three positioning mark points and their coordinates on the plane drawing of the sheet metal workpiece; S2, obtaining the actual coordinates of the mark point on the machine; S3, generating a corresponding two-dimensional position vector according to the coordinates of the mark points on the drawing and the machine; S4, comparing the drawing coordinate vector with the machine coordinate vector to determine the angular change of the workpiece; S5, rotating all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change; S6, calculating the translation amount between the rotated drawing coordinates and the machine coordinates; S7, constructing a rigid transformation matrix by combining rotation and translation information; S8, using the rigid transformation matrix to convert the coordinates of other points on the drawing into coordinates in the machine coordinate system.

7. The method for calculating the center positioning of a workpiece by riveting according to claim 6, characterized in that: In step S2, when obtaining the actual coordinates of the mark point, the position of the mark point on the workpiece is automatically detected by camera vision or other non-contact measurement technology.

8. The method for calculating the center positioning of a workpiece by riveting according to claim 6, characterized in that: The method can handle the situation where there are only two mark points and calculate the accurate position of the workpiece based on them.

9. The method for calculating the center positioning of a workpiece by riveting according to claim 6, characterized in that: The method further includes a verification step S9 for verifying whether the converted coordinates meet the preset accuracy requirements.

10. The method for calculating the center positioning of a workpiece by riveting according to claim 6, characterized in that: The method further comprises a step S10 of transmitting the converted coordinate data to a riveting device so as to perform a precise riveting operation.

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