A calculation method and system for positioning workpieces by riveting center

Abstract

The present invention provides a calculation method and system for positioning a workpiece by a riveting center. The system includes: a data acquisition module for acquiring the coordinates of a positioning mark point on a planar drawing and the actual coordinates of the mark point on a machine; a vector generation module for generating a two-dimensional position vector; an angle comparison module for comparing angle changes; a coordinate rotation module for rotating all coordinates in the drawing coordinate system to match the direction of the machine coordinate system according to the angle change; a translation calculation module for calculating the translation amount based on the rotated drawing coordinates and the machine coordinates; a transformation matrix construction module for constructing a rigid transformation matrix based on the rotation and translation information; and a coordinate conversion module for converting the coordinates of other points on the drawing into coordinates in the machine coordinate system. The present invention uses a geometric method to obtain the conversion relationship from drawing coordinates to machine coordinates. It does not need to meet the strict requirements of matrix properties in linear algebra, can handle the case of only two mark points, and can directly obtain the angular change of the workpiece.

Description

Technical Field

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

[0002] In modern manufacturing, riveting is a common joining process used to secure two or more sheet metal parts together. To ensure the quality and accuracy of the riveting process, workpiece positioning is a critical step. Traditional riveting often requires manual workpiece placement and positioning, which is not only time-consuming and labor-intensive but also prone to human error, impacting the quality of the final product. With the advancement of automation technology, automated riveting centers are gradually being adopted. These machines automate the riveting process by importing workpiece drawings and automatically finding the workpiece's working position.

[0003] In existing technology, riveting centers typically use linear algebraic transformations to determine the conversion relationship between drawing coordinates and machine coordinates. This method calculates a transformation matrix based on the marking points on the drawing (usually hole locations), thereby converting the positions of other feature points on the drawing into positions in the machine coordinate system, guiding the machine for precise operation. However, this linear algebra-based method has some limitations and shortcomings.

[0004] Deficiencies of existing technology:

[0005] 1. Strict data requirements: 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 located on a straight line, this method cannot be used to calculate the transformation relationship.

[0006] 2. Limited scope of application: Due to the aforementioned data requirements, existing technologies are difficult to apply in some cases, especially when there are a small number of markers or their distribution is not ideal. For example, when there are only two markers, traditional methods may not provide enough information for accurate positioning.

[0007] 3. Lack of flexibility: Existing methods have poor adaptability to changes in input data. Once unexpected situations are encountered (such as collinear mark points), additional manual intervention or adjustments are required, which reduces the degree of automation of the system.

[0008] 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.

[0009] Therefore, the existing technology has deficiencies and needs further improvement. Summary of the Invention

[0010] 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.

[0011] To achieve the above object, the specific solutions of the present invention are as follows:

[0012] The present invention provides a calculation system for positioning a workpiece by a riveting center, the system comprising:

[0013] A data acquisition module is used to obtain the coordinates of at least three positioning mark points on the sheet metal workpiece plane drawing and the actual coordinates of the mark points on the machine;

[0014] Vector generation module, used to generate corresponding two-dimensional position vectors according to the coordinates of mark points on the drawing and the machine;

[0015] An angle comparison module for comparing the drawing coordinate vector with the machine coordinate vector to determine the angular change of the workpiece;

[0016] Coordinate rotation module, used to rotate all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change;

[0017] A translation calculation module is used to calculate the translation amount based on the rotated drawing coordinates and the machine coordinates;

[0018] Transformation matrix construction module, used to construct a rigid transformation matrix by combining rotation and translation information;

[0019] 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.

[0020] 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 machine moving platform.

[0021] Furthermore, the data acquisition module can also handle the situation where there are only two mark points, and accordingly achieve accurate positioning of the workpiece.

[0022] 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.

[0023] Furthermore, the system includes a user interface that allows an operator to input parameters, monitor the process, and receive system feedback.

[0024] 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:

[0025] S1, obtaining at least three positioning mark points and their coordinates on the plane drawing of the sheet metal workpiece;

[0026] S2, obtaining the actual coordinates of the mark point on the machine;

[0027] S3, generate the corresponding two-dimensional position vector according to the coordinates of the mark points on the drawing and the machine;

[0028] S4, comparing the drawing coordinate vector and the machine coordinate vector to determine the angular change of the workpiece;

[0029] S5, rotating all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change;

[0030] S6, calculating the translation between the rotated drawing coordinates and the machine coordinates;

[0031] S7, constructs a rigid transformation matrix by combining rotation and translation information;

[0032] S8, using the rigid transformation matrix to convert the coordinates of other points on the drawing into coordinates in the machine coordinate system.

[0033] 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.

[0034] Furthermore, the method can handle the situation where there are only two mark points and calculate the accurate position of the workpiece based on them.

[0035] Furthermore, the method further includes a verification step S9 for verifying whether the converted coordinates meet preset accuracy requirements.

[0036] 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.

[0037] The technical solution of the present invention has the following beneficial effects:

[0038] 1. Reduce the requirements for matrix properties:

[0039] Traditional linear algebraic transformation methods require certain strict mathematical conditions to be met, such as matrix full rank and positive definiteness. The method of the present invention does not require these restrictions and can therefore work properly even when the mark points are collinear, improving the applicability and robustness of the system.

[0040] 2. Support fewer mark points:

[0041] 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.

[0042] 3. Directly obtain angle changes:

[0043] By comparing the angles of the drawing coordinate vectors with the machine coordinate vectors, 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 simplify subsequent rotation and translation calculations.

[0044] 4. Simplify the algorithm process:

[0045] Compared with complex linear algebraic operations, the present invention adopts a geometric method to simplify the calculation process of the conversion relationship. This not only reduces the computational complexity, but also speeds up the system's response time and improves production efficiency.

[0046] 5. Improve positioning accuracy:

[0047] Through precise geometric calculations and the application of rigid transformation matrices, the present invention can provide high-precision workpiece positioning, ensure the accuracy of the riveting operation, and thus improve the quality of the final product.

[0048] 6. Enhanced automation:

[0049] Since the method of the present invention can automatically process mark point data in various situations, the need for manual intervention is reduced, the degree of automation of the riveting center machine is further enhanced, and the labor cost is reduced.

[0050] 7. Wide applicability:

[0051] The technology of the present invention is not only applicable to standard three-hole positioning, but also to situations with only two mark points, and can even be extended to other similar application scenarios, with high versatility and adaptability.

[0052] 8. Easy to implement and integrate:

[0053] 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 requiring major modifications to existing hardware.

[0054] 9. Improve production efficiency:

[0055] 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

[0056] Figure 1 It is a schematic drawing diagram of the present invention;

[0057] Figure 2 It is a schematic diagram of the coordinate vectors of the drawing of the present invention;

[0058] Figure 3 is a schematic diagram of the machine coordinate vectors of the present invention;

[0059] Figure 4 It is a schematic diagram of the rotation amount calculation of the present invention;

[0060] Figure 5 Schematic diagram of calculating the rotation and translation amount of the present invention;

[0061] Figure 6 Schematic diagram of calculating displacement translation of the present invention;

[0062] Figure 7 It is the overall flow chart of the present invention. DETAILED DESCRIPTION

[0063] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It will be understood that the specific embodiments described herein are merely intended to explain the present invention rather than to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only show portions related to the present invention rather than all of the present invention.

[0064] Combine Figure 1-Figure 7 As shown, the present invention provides a calculation system for positioning a workpiece by a riveting center, the system comprising:

[0065] A data acquisition module is used to obtain the coordinates of at least three positioning mark points on the sheet metal workpiece plane drawing and the actual coordinates of the mark points on the machine;

[0066] Vector generation module, used to generate corresponding two-dimensional position vectors according to the coordinates of mark points on the drawing and the machine;

[0067] An angle comparison module for comparing the drawing coordinate vector with the machine coordinate vector to determine the angular change of the workpiece;

[0068] Coordinate rotation module, used to rotate all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change;

[0069] A translation calculation module is used to calculate the translation amount based on the rotated drawing coordinates and the machine coordinates;

[0070] Transformation matrix construction module, used to construct a rigid transformation matrix by combining rotation and translation information;

[0071] 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.

[0072] 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.

[0073] The data acquisition module can also handle the situation where there are only two mark points, and accordingly achieve accurate positioning of the workpiece.

[0074] 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.

[0075] The system also includes a user interface that allows an operator to input parameters, monitor the process, and receive system feedback.

[0076] 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:

[0077] S1, obtaining at least three positioning mark points and their coordinates on the plane drawing of the sheet metal workpiece;

[0078] S2, obtaining the actual coordinates of the mark point on the machine;

[0079] S3, generate the corresponding two-dimensional position vector according to the coordinates of the mark points on the drawing and the machine;

[0080] S4, comparing the drawing coordinate vector and the machine coordinate vector to determine the angular change of the workpiece;

[0081] S5, rotating all coordinates in the drawing coordinate system to match the orientation of the machine coordinate system according to the angle change;

[0082] S6, calculating the translation between the rotated drawing coordinates and the machine coordinates;

[0083] S7, constructs a rigid transformation matrix by combining rotation and translation information;

[0084] S8, using the rigid transformation matrix to convert the coordinates of other points on the drawing into coordinates in the machine coordinate system.

[0085] 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.

[0086] 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.

[0087] The method further includes a verification step S9 for verifying whether the converted coordinates meet the preset accuracy requirements.

[0088] 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.

[0089] Working principle of the present invention:

[0090] This paper proposes a method and system for calculating the center position of a workpiece using geometric methods. This method and system aims to automatically convert drawing coordinates to machine coordinates, thereby guiding the precise positioning of the center machine. The detailed working principle is as follows:

[0091] 1. Get drawing information

[0092] 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.

[0093] Purpose: These mark points will serve as reference points for subsequent coordinate transformation calculations.

[0094] 2. Generate drawing coordinate vectors

[0095] Steps: Based on the coordinates of the mark points on the drawing, make a pairwise difference to obtain the two-dimensional position vector between each mark point and other mark points.

[0096] Purpose: These vectors represent the relative position relationship between the mark points and provide basic data for subsequent angle comparison.

[0097] 3. Get the actual coordinates

[0098] Steps: Place the workpiece on the mobile platform of the machine, and detect and obtain the actual machine coordinates of the mark points on the workpiece through camera vision or other means.

[0099] Purpose: Actual coordinates are the basis of machine operation and are used for comparison and conversion with drawing coordinates.

[0100] 4. Generate machine coordinate vector

[0101] Steps: Similarly, based on the actual acquired mark point coordinates, generate a two-dimensional position vector between each mark point and other mark points.

[0102] Purpose: These vectors are used to compare with the drawing coordinate vectors to determine the angular change of the workpiece.

[0103] 5. Compare angle changes

[0104] 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.

[0105] Purpose: By comparing angles, we can understand how the workpiece rotates during placement, which is a key step in constructing the rigid transformation matrix.

[0106] 6. Rotate the drawing coordinates

[0107] 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 orientation of the machine coordinate system.

[0108] Purpose: The coordinates of the rotated drawing are consistent with the direction of the machine coordinate system, preparing for the next translation calculation.

[0109] 7. Calculate the translation

[0110] Steps: Compare the rotated drawing coordinates with the actual machine coordinates, and calculate the displacement required after the rotation, that is, the translation.

[0111] Purpose: By calculating the translation amount, the exact position of the workpiece in the machine coordinate system can be determined.

[0112] 8. Constructing a rigid transformation matrix

[0113] Steps: Combine the rotation and translation information 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.

[0114] 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.

[0115] 9. Applying the Transformation Matrix

[0116] 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.

[0117] Purpose: The converted coordinates can be directly used to guide the riveting equipment to perform precise processing operations.

[0118] Summarize

[0119] This invention uses geometric methods, particularly vector calculations and angle comparisons, to avoid the strict matrix properties (such as full rank and positive definiteness) required by traditional linear algebra methods. This approach not only simplifies the calculation process and improves the system's flexibility and reliability, but also enables accurate positioning even with only two mark points. Ultimately, 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 automated riveting equipment.

[0120] Example 1:

[0121] A riveting center machine (hereinafter referred to as the machine) automatically locates the workpiece's working position, eliminating manual labor and achieving automated riveting. To achieve this function, the machine requires an imported workpiece drawing with at least three hole locations marked for positioning, referred to as mark points. In actual production, the workpiece is placed on the machine's mobile platform. The positions of the workpiece's mark points are acquired using camera vision or other methods. The acquired machine coordinates are compared with the coordinates in the drawing to calculate the conversion relationship from the drawing coordinates to the machine coordinates. This can then be used to calculate the machine coordinates of the hole locations on other drawings, thus achieving positioning. Existing machines often use linear algebraic transformations to obtain this conversion relationship. This method requires certain properties of linear matrices to be met, such as full rank and positive definiteness. For example, it cannot be used when three mark points lie on a straight line.

[0122] The method of obtaining the above transformation relationship by geometric method is divided into the following main steps:

[0123] 1. Obtain the planar drawing information of the sheet metal workpiece, including the coordinates of the workpiece's mark points on the drawing.

[0124] 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.

[0125] 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 selected mark points on the drawing are shown. For example, if three points A, B, and C are selected, vectors AB, AC, BA, etc. are displayed;

[0126] 3. After obtaining the machine coordinates of the workpiece's mark points on the machine, the coordinates of the mark points are subtracted to obtain the two-dimensional position vector of each mark point and the other mark points. The machine coordinate vector diagram is as follows: Figure 3 shown.

[0127] 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.

[0128] 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 in Figure 2, it is a schematic diagram for calculating the rotation and translation.

[0129] 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 Figure 2, it is a schematic diagram for calculating the displacement translation.

[0130] 7. Combining the rotation change in step 5 and the translation change in step 6, we can get the rigid transformation matrix from the drawing coordinates to the machine coordinates. The following is the two-dimensional rigid transformation matrix model:

[0131]

[0132] The method:

[0133] 1. It can avoid some matrix property conditions that must be met in linear algebra methods, such as full rank and positive definite.

[0134] 2. The angle of the workpiece can be obtained.

[0135] 3. Two mark points can also be calculated.

[0136] 1. The geometric method is used to achieve the goal of positioning the workpiece in the riveting center machine.

[0137] 2. The specific method is to obtain the relative position vector between the coordinates of the points to determine the rotation angle. After the rotation angle is determined, the rigid transformation matrix from the drawing coordinates to the machine coordinates is calculated by calculating the rotation translation and displacement translation, which is used to locate other points on the workpiece.

[0138] Comparing the calculation example with the result, the calculation result is consistent with the meas measurement value:

[0139] The code is as follows:

[0140] / / The first reference case

[0141] data.ref1.x = 0; data.ref1.y = 0;

[0142] data.ref2.x = 500; data.ref2.y = 0;

[0143] data.ref3.x = 0; data.ref3.y = 400;

[0144] / / 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

[0145] data.meas1.x = 0 + 30; data.meas1.y = 0 - 50;

[0146] data.meas2.x = -433.0127 + 30; data.meas2.y = 250 - 50;

[0147] data.meas3.x = -200 + 30; data.meas3.y = -346.4102 - 50;

[0148] double angle = Radian2degree(CalcTheta3Marks(&data));

[0149] printf("theta = %f\n", angle);

[0150] ret = CalcCoord3Marks(&data,&data.ref1);

[0151] printf("calculated x1 = %f, calculated y1 = %f\n", ret.x, ret.y); ;

[0152] ret = CalcCoord3Marks(&data,&data.ref2);

[0153] printf("calculated x2 = %f, calculated y2 = %f\n", ret.x, ret.y);

[0154] ret = CalcCoord3Marks(&data,&data.ref3);

[0155] printf("calculated x3 = %f, calculated y3 = %f\n", ret.x, ret.y);

[0156] Result output:

[0157] theta = 150.000000

[0158] calculated x1 = 30.000000, calculated y1 = -50.000011

[0159] calculated x2 = -403.012703, calculated y2 = 199.999986

[0160] calculated x3 = -169.999997, calculated y3 = -396.410174

[0161] Specific embodiment 2: (three mark points)

[0162] The present invention relates to a method and system for positioning a workpiece using geometric methods to calculate the center of a press riveting machine. The system automatically converts coordinates on a drawing into machine coordinates, thereby guiding the press riveting machine for precise positioning. The following is a specific implementation example.

[0163] In this example, we will use a sheet metal workpiece with three holes (used as marks). There are some rotational and translational deviations between the workpiece drawing 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 coordinate system using the method of this invention.

[0164] Detailed steps

[0165] Get drawing information

[0166] Suppose we have three hole marking points A, B, and C, whose coordinates on the drawing are (0, 0), (100, 0), and (50, 86.6), respectively, in millimeters.

[0167] Generate drawing coordinate vector

[0168] Calculate vector AB: (100-0, 0-0) = (100, 0)

[0169] Calculate the vector AC: (50-0, 86.6-0) = (50, 86.6)

[0170] Get actual coordinates

[0171] Use a vision 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.

[0172] Generate machine coordinate vector

[0173] Calculate vector A'B': (110-10, 20-20) = (100, 0)

[0174] Calculate vector A'C': (60-10, 106.6-20) = (50, 86.6)

[0175] Comparing angle changes

[0176] 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.

[0177] Likewise, compare the angles of the drawing vector AC and the machine vector A'C' to confirm that there is no additional rotation.

[0178] Rotate drawing coordinates

[0179] Since no rotation is detected, the drawing coordinates do not need to be rotated.

[0180] Calculate the translation

[0181] 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.

[0182] Constructing a rigid transformation matrix

[0183] Since there is no rotation, the transformation matrix simplifies to just the translation component:

[0184] Dark version

[0185] T = [1, 0, 10;

[0186] 0, 1, 20;

[0187] 0, 0, 1]

[0188] Applying a transformation matrix

[0189] For any point P(x, y) on the drawing, its new coordinates P'(x', y') in the machine coordinate system can be obtained as follows:

[0190] Dark version

[0191] P' = T * P

[0192] = [1, 0, 10; 0, 1, 20; 0, 0, 1] * [x; y; 1]

[0193] = [x + 10; y + 20; 1]

[0194] Therefore, the new coordinates P' of any point P on the drawing are its original coordinates plus a fixed offset (10, 20).

[0195] Verification

[0196] Through the above steps, we have successfully converted the drawing coordinates into machine coordinates, which 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 measurements. If all points are consistent with the expected values, the method is proven to be effective and reliable.

[0197] This specific embodiment demonstrates how to use the technology of the present invention to achieve the conversion from drawing coordinates to machine coordinates, ensuring precise positioning in the riveting process.

[0198] Specific embodiment 3 (two mark points)

[0199] The present invention provides a method and system for calculating the center of a press riveted workpiece using 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, where these mark points are rotated and translated during actual placement.

[0200] Suppose we have a sheet metal workpiece with two holes (used as marks), and there are some rotational and translational deviations between the workpiece drawing 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 coordinate system using the method of this invention.

[0201] Detailed steps

[0202] Get drawing information

[0203] 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.

[0204] Generate drawing coordinate vector

[0205] Calculate vector AB: (100-0, 0-0) = (100, 0)

[0206] Get actual coordinates

[0207] Use a vision 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.

[0208] Generate machine coordinate vector

[0209] Calculate vector A'B': (100-20, 90-30) = (80, 60)

[0210] Comparing angle changes

[0211] Calculate the angle change between vector AB and vector A'B'.

[0212] The direction angle of vector AB is θ_AB = atan2(0, 100) = 0°

[0213] The direction angle of vector A'B' is θ_A'B' = atan2(60, 80) ≈ 36.87°

[0214] Angle change Δθ = θ_A'B' - θ_AB = 36.87°

[0215] Rotate drawing coordinates

[0216] Rotate all coordinates in the drawing coordinate system by the angle change Δθ.

[0217] Rotation matrix R:

[0218] Dark version

[0219] R = [cos(Δθ), -sin(Δθ);

[0220] sin(Δθ), cos(Δθ)]

[0221] = [cos(36.87°), -sin(36.87°);

[0222] sin(36.87°), cos(36.87°)]

[0223] ≈ [0.8, -0.6;

[0224] 0.6, 0.8]

[0225] Rotate points A(0, 0) and B(100, 0) on the drawing:

[0226] A' = R * [0; 0] = [0; 0]

[0227] B' = R * [100; 0] = [80; 60]

[0228] Calculate the translation

[0229] Compare the rotated drawing coordinates with the actual machine coordinates and calculate the translation amount.

[0230] Translation ΔX = 20 - 0 = 20 mm

[0231] Translation ΔY = 30 - 0 = 30 mm

[0232] Constructing a rigid transformation matrix

[0233] Combining the information of rotation and translation, construct the rigid transformation matrix T:

[0234] Dark version

[0235] T = [cos(Δθ), -sin(Δθ), ΔX;

[0236] sin(Δθ), cos(Δθ), ΔY;

[0237] 0, 0, 1]

[0238] ≈ [0.8, -0.6, 20;

[0239] 0.6, 0.8, 30;

[0240] 0, 0, 1]

[0241] Applying a transformation matrix

[0242] For any point P(x, y) on the drawing, its new coordinates P'(x', y') in the machine coordinate system can be obtained as follows:

[0243] Dark version

[0244] P' = T * P

[0245] = [0.8, -0.6, 20;

[0246] 0.6, 0.8, 30;

[0247] 0, 0, 1] * [x; y; 1]

[0248] = [0.8 * x - 0.6 * y + 20;

[0249] 0.6 * x + 0.8 * y + 30; 1]

[0251] Therefore, the new coordinates P' of any point P on the drawing are its coordinates after rotation and translation.

[0252] Verification

[0253] 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, suppose there is another point C(50, 0) on the drawing, we can calculate its position in the machine coordinate system:

[0254] C' = T * [50; 0; 1]

[0255] = [0.8 * 50 - 0.6 * 0 + 20;

[0256] 0.6 * 50 + 0.8 * 0 + 30; 1]

[0258] = [60; 60; 1]

[0259] 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.

[0260] This specific embodiment demonstrates how to utilize the technology of the present invention to handle a situation with only two mark points, and to accurately calculate rotation and translation, thereby ensuring precise positioning in the riveting process.

[0261] The above description is only a preferred embodiment of the present invention and does not limit the scope of the invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application 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 riveting center, characterized in that: The system includes: A data acquisition module is used to obtain the coordinates of at least three positioning mark points on the sheet metal workpiece plane drawing and the actual coordinates of the mark points on the machine; Vector generation module, used to generate corresponding two-dimensional position vectors according to the coordinates of 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; Coordinate rotation module, 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 based on the rotated drawing coordinates and the 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 calculation system for positioning a workpiece by a press riveting center according to claim 1, wherein: 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 press 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 calculation system for positioning a workpiece by a press riveting center according to claim 1, wherein: 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 calculation system for positioning a workpiece by a press riveting center according to claim 1, wherein: 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, generate the 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 and 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 between the rotated drawing coordinates and the machine coordinates; S7, constructs 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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.

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