Method and system for obtaining actual material distribution diagram of tire and computer program product

Abstract

The invention relates to the technical field of tire simulation design, in particular to a method and system for obtaining an actual material distribution diagram of a tire and a computer program product. According to the method, the outer contour and the material distribution diagram are accurately matched by scanning the outer contour of an actual tire, combining with the material distribution diagram of the section of the tire and adopting smooth processing and affine transformation technologies. The method comprises the specific steps of scanning the outer contour of a tire, drawing a material distribution diagram, smoothing the contour, selecting and equally dividing a mapping curve, calculating an affine transformation matrix, dividing the material distribution diagram into a plurality of small areas, and executing affine transformation on the small areas to generate an actual material distribution diagram. According to the method, the simulation precision is remarkably improved, the correction time is shortened, and the method is suitable for various tire models and complex structures. The material distribution map generated by the method can provide accurate data support for performance optimization of tire rolling resistance, stress analysis and the like, and has wide application value.

Description

Technical Field

[0001] The present invention relates to the technical field of tire simulation design, and in particular to a method, system and computer program product for obtaining an actual material distribution diagram of a tire. Background Art

[0002] A tire is a complex composite structure whose performance is directly affected by material distribution and structural characteristics. However, due to differences in process parameters, material properties and component dimensions during the manufacturing process, the material distribution and geometry of the tires actually produced often deviate greatly from the designed prototype. Existing tire performance simulation analysis methods are usually modeled based on mold design contours, but this method is difficult to truly reflect the material distribution and structural characteristics of the actual tire, resulting in a significant difference between the simulation results and the actual performance.

[0003] Although some existing technologies attempt to correct the design model through the actual tire cross-section diagram, these methods usually only adjust the thickness of the internal components, and the outer contour is still based on the mold design. This type of correction method not only makes it difficult to improve the overall accuracy of the simulation model, but also faces the problem of a long adjustment process. The Chinese invention patents applied for by the applicant (such as Patent 2021116135564, Patent 2022100923567 and Patent 2022105620611) proposed several simulation analysis methods for tire performance, but none of them solved the problem that the actual material distribution does not match the design model. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a method for obtaining an actual material distribution map for tire performance analysis. By introducing affine transformation technology, the cross-sectional material distribution of the actual tire is accurately matched with the outer contour data, thereby quickly and accurately generating a material distribution map consistent with the actual tire. This method can significantly improve the accuracy of performance simulation analysis and provide more reliable data support for tire design and optimization.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: A method for obtaining an actual material distribution map for tire performance analysis, characterized by comprising the following steps: 1) External contour scanning: Inflate the tire to standard pressure, then deflate it to an internal pressure of 0.01-0.1MPa, use a laser scanner to obtain the tire's external contour and save it as a vector file; 2) Material distribution map drawing: Based on the actual tire section, use CAD software to draw the material distribution map of the tire; 3) Outer contour smoothing: Smooth the outer contour data to eliminate the roughness and obtain a smoothed outer contour curve; 4) Material distribution map smoothing: Smooth the outer contour of the drawn material distribution map to obtain a smoothed material distribution map curve; 5) Mapping curve selection and equal division: Select some continuous curves from the smoothed outer contour curve and material distribution curve respectively for equal division, the number of equal divisions is n, and generate the target curve set and the original curve set; 6) Affine transformation matrix calculation: Calculate the affine transformation matrix based on the target curve node coordinates and the original curve node coordinates; 7) Region division: Generate multiple small regions according to equally divided points based on the mapping curve; 8) Affine transformation: Perform affine transformation on the point coordinates of each small area and update them to the point coordinates of the actual material distribution map.

[0006] Preferably, the outer contour smoothing process in step 4) includes: a) Use arc to block the concave part of the groove; b) Use arcs to smooth out the rough curves caused by grooves, decorative lines and font lines.

[0007] Preferably, the affine transformation matrix in step 6) is calculated by the following formula:

[0008] in x * k , y* k represents the coordinates of the points on the original curve, x k and y k represents the coordinates of the point on the target curve, a k , b k , c k , d k , p k , q k are the affine transformation coefficients.

[0009] Preferably, in step 7), the principle of equally dividing the mapping curve is that the length of each curve portion is not greater than 0.5 mm, and the number of equally divided portions n is an even number and greater than 30.

[0010] Preferably, the affine transformation in step 8) is calculated by the following formula:

[0011] in x * m , y* m represents the coordinates of the points on the original curve, x m and y m represents the coordinates of the point on the target curve, a m , b m , c m , d m , p m , q m are the affine transformation coefficients.

[0012] Furthermore, the present invention also provides a system for obtaining an actual material distribution map of a tire, wherein the system implements the method, including: Laser scanning module: used to scan the outer contour of the tire and generate a vector file containing the outer contour data; Drawing module: used to import actual cross-section images and draw tire material distribution maps; Smoothing module: smoothing the tire outer contour and material distribution map; Affine transformation module: used to calculate the affine transformation matrix and perform affine transformation operations on small areas; Segmentation module: used to segment the material distribution map into multiple small areas according to the mapping curve; Output module: Output updated actual material distribution map.

[0013] Preferably, the affine transformation module comprises: The node extraction submodule is used to extract the coordinates of equally divided nodes of the mapping curve; A matrix calculation submodule, used to calculate the affine transformation matrix based on the node coordinates; The coordinate transformation submodule is used to perform coordinate affine transformation of small areas.

[0014] As a preference, the output module can export the updated material distribution map into a variety of formats, including dxf, svg or other compatible formats, to facilitate subsequent simulation analysis.

[0015] Furthermore, the present invention also provides a computer-readable storage medium having a computer program or instruction stored thereon, and the method is implemented when the computer program or instruction is executed by a processor.

[0016] Furthermore, the present invention also provides a computer program product, comprising a computer program or instructions, which implement the method when executed by a processor.

[0017] The present invention adopts the above technical solution and proposes a method and system for obtaining the actual material distribution map for tire performance analysis. By introducing the affine transformation technology, the cross-sectional material distribution of the actual tire is accurately matched with the outer contour data, so as to quickly and accurately generate a material distribution map consistent with the actual tire. It can effectively solve the problem of the inconsistency between the simulation model and the actual tire structure in the prior art and achieve the following technical effects: 1. Improve simulation accuracy: By introducing affine transformation technology, the cross-sectional material distribution of the actual tire is accurately matched with the outer contour data, and the generated material distribution map is closer to the actual tire structure. Compared with the simulation analysis based on mold contour in the prior art, the simulation results generated by the method of the present invention have a higher degree of consistency with the actual test data, which significantly improves the accuracy of performance analysis.

[0018] 2. Optimize the structural restoration process: The present invention simultaneously smoothes the outer contour and material distribution map, eliminates structural interference factors such as grooves, decorative lines and fonts, thereby improving the smoothness and consistency of the curve and ensuring the overall accuracy of the simulation model.

[0019] 3. Shorten the correction time: Through the method of region segmentation and independent affine transformation, the present invention avoids the tedious process of point-by-point correction of tire cross-section in traditional methods, realizes the rapid generation of material distribution maps, and significantly reduces the time required for tire simulation modeling.

[0020] 4. Enhanced modeling flexibility: The method of the present invention supports regional processing of complex geometric structures of tires, and the affine transformation parameters between each region can be calculated independently, so that the method can adapt to the modeling requirements of tires of different models, sizes and complex structures.

[0021] 5. Improve application value: The actual material distribution map generated by the present invention makes subsequent simulation analysis more reliable, providing a more accurate data basis for performance optimization such as tire rolling resistance and pinning force analysis. This can not only improve the efficiency of tire product design, but also provide important technical support for quality control and performance optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Scan the outer contour of the tire; Figure 2 It is the actual cross-sectional image of the tire; Figure 3 It is a material distribution map drawn according to the actual section; Figure 4To smooth the outer contour of the scan; Figure 5 For smooth processing of the tread grooves; Figure 6 Smoothing of contour fluctuations caused by decorative buttons or fonts; Figure 7 Scan the image for the smoothed contour; Figure 8 This is a tire material distribution diagram after smoothing; Fig. 9 is the mapping target curve on the S_S_P contour; Fig.10 is the original curve mapped on the S_M_P contour; Fig.11 Calculate the result for the affine matrix; Fig.12 Schematic diagram of segmentation processing of contour map; Fig.13 The final contour image is consistent with the scanned outer contour; Fig.14 To compare the simulation analysis profile using the mold profile with the actual measurement; Fig.15 To compare the simulated analysis profile performed on the transformed profile with the actual measurement. DETAILED DESCRIPTION

[0023] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The present invention proposes a method for obtaining an actual material distribution map for tire performance analysis, which introduces affine transformation technology to accurately match the cross-sectional material distribution of the actual tire with the outer contour data, thereby quickly and accurately generating a material distribution map consistent with the actual tire. Specifically, the method includes the following steps: Step 1: Inflate the tire to the standard pressure, then deflate the tire until the internal pressure is 0.05Mpa, use a laser scanner to scan the outer contour of the tire, record it as O_S_P, and obtain a dxf file containing the outer contour of the tire; Step 2: Import the image into the CAD software, and draw the material distribution map of the tire according to the actual cross-section, which is recorded as O_M_P. This material distribution map is the material distribution map of the cut tire section, which is in a relaxed state and has a large difference from the actual tire profile; Step 3: Smooth the outer contour of the tire. Since the actual outer contour of the tire contains elements such as grooves, decorative lines, and fonts, the O_S_P line is not smooth, so it needs to be manually processed into a smooth curve. For the grooves, the concave part is blocked with a smooth arc, and the unevenness caused by decorative lines and fonts is smoothed with an arc. The final smoothed curve is recorded as S_S_P; Step 4: Smooth the outer contour curve of the tire material distribution map. The actual tire material distribution map also has uneven curves caused by tread grooves, decorative lines and font lines. Similarly, the material distribution map needs to be smoothed in the same way as in step 3. The final smoothed curve is recorded as S_M_P; Step 5: Select the curve set to be mapped. Select some continuous curves on the S_S_P contour as the target curve for mapping, and divide it into equal parts. The principle of equal division is that the length of each part is not more than 0.5mm, and the number of equal divisions is n (n>30, and n is an even number). The target curve after equal division is recorded as M_S_P. Select some continuous curves on S_M_P as the original curve for mapping, and divide it into equal parts. The number of equal divisions is also n, and the target curve after equal division is recorded as M_M_P. Step 6: Extract the node coordinates on M_S_P in counterclockwise order, denoted as MSP j , where j = 0~n. Similarly, extract the node coordinates on M_M_P in counterclockwise order, denoted as MMP i , where i = 0~n, take out the nodes in turn (MSP 2k , MSP 2k+1 , MSP 2k+2 ) coordinates, and nodes (MMP 2k , MMP 2k+1 , MMP 2k+2 ) coordinates, where k = (0, n / 2-1), according to (MSP 2k , MSP 2k+1 , MSP 2k+2 ) and (MMP 2k , MMP 2k+1 , MMP 2k+2 ) The coordinates of the six nodes are calculated according to the following formula to calculate the affine transformation matrix: (1) in x * k , y* k represents the coordinates of the point on the M_S_P curve, x k and y krepresents the coordinates of the point on the M_M_P curve, a k , b k , c k , d k , p k , q k These coefficients include translation, scaling and rotation operations.

[0025] Step 7: Divide the material distribution map into multiple small areas. For the tire material distribution map, according to the selected MMP curve, 2k Points and MSP 2k+2 Find the perpendicular line of MMP line, denoted by N 2k and N 2k+2 , where k = 0 ~ n / 2-1, extract the material distribution map located in N 2k and N 2k+2 The line segment or figure between them is denoted as P k , outside N0, and N n The two regions outside are denoted as P -1 and P n+1 , n is the number of equal parts in the fifth step.

[0026] Step 8: Small area P m (m=-1~n+1) performs affine transformation. m Perform an affine transformation. For P m The coordinates of the graphics contained in , using their corresponding affine transformation parameters a m , b m , c m , d m , p m , q m , the coordinates of the transformed point are obtained according to the following formula: (2) Calculate P -1 Point-time utilization coefficient within the region a 0 , b 0 , c 0 , d 0 , p0 , q 0 To calculate, use a n , b n , c n , d n , p n , q n P n+1 The points in the area are transformed. The linear composition of the original material distribution diagram remains unchanged, and the coordinates of the points are updated to the coordinates after affine transformation. At this point, the material distribution diagram of the actual tire is obtained.

[0027] Taking the 24570R17 tire as an example, in order to more intuitively illustrate the technical route of this patent, this embodiment only changes the inner and outer contours: Step 1: Inflate the tire to a standard pressure of 0.25 MPa, then deflate the tire until the internal pressure is 0.05 MPa. Use a laser scanner to scan the outer contour of the tire, recorded as O_S_P, as shown in the figure Figure 1 As shown; Step 2: According to the actual cross-section conditions (such as Figure 2 ), the tire profile is drawn (to represent the tire material distribution map), denoted as O_M_P, such as Figure 3 As shown, this material distribution diagram is a material distribution diagram of a cut tire section, which is in a relaxed state and is quite different from the actual tire profile; Step 3: Smooth the outer contour of the tire. Since the actual outer contour of the tire contains elements such as grooves, decorative lines, fonts, etc., the O_S_P line is not smooth, so it needs to be manually processed into a smooth curve (such as Figure 4 As shown in the figure), the concave part of the groove is sealed with a smooth arc (as shown in the figure). Figure 5 As shown in the figure, the roughness caused by decorative lines and fonts is smoothed by arcs (as shown in the figure). Figure 6 ), the final smoothed curve is recorded as S_S_P, such as Figure 7 ; Step 4: Smooth the outer contour curve of the tire material distribution map. The actual tire material distribution map also has uneven curves caused by tread grooves, decorative lines and font lines. Similarly, the material distribution map needs to be smoothed in the same way as in step 4. The final smoothed curve is recorded as S_M_P, as shown in Figure 8 As shown; Step 5: Select the curve set to be mapped. Select some continuous curves on the S_S_P contour as the target curve for mapping, such as Fig. 9 , and divide it into equal parts. The principle of equal division is that the length of each part is not greater than 0.5 mm, and the number of equal parts is n=80. The target curve after equal division is recorded as M_S_P. Select some continuous curves on S_M_P as the original curve for mapping, such as Fig.10 As shown, it is also divided into equal parts, the number of equal parts is also n=80, and the target curve after equal division is recorded as M_M_P; Step 6: Extract the node coordinates on M_S_P in counterclockwise order, denoted as MSP j , where j = 0 ~ 80. Similarly, extract the node coordinates on M_M_P in counterclockwise order, denoted as MMP i , where i = 0~80, take out the nodes in turn (MSP 2k , MSP 2k+1 , MSP 2k+2 ) coordinates, and nodes (MMP 2k , MMP 2k+1 , MMP 2k+2 ) coordinates, where k = (0, 39), according to (MSP 2k , MSP 2k+1 , MSP 2k+2 ) and (MMP 2k , MMP 2k+1 , MMP 2k+2 ) The coordinates of the six nodes are calculated according to the following formula to calculate the affine transformation matrix: (1) in x * k , y* k represents the coordinates of the point on the M_S_P curve, x k and y k represents the coordinates of the point on the M_M_P curve, a k , b k , c k , d k , p k , q k are coefficients, which include translation, scaling and rotation operations. The calculation results are as follows Fig.11 .

[0028] Step 7: Divide the material distribution map into multiple small areas. For the tire material distribution map, according to the selected MMP curve,2k Points and MSP 2k+2 Find the perpendicular line of MMP line, denoted by N 2k and N 2k+2 , where k = 0~39, extract the material distribution map located in N 2k and N 2k+2 The line segment or figure between them is denoted as P k , outside N0, and N n The two regions outside are denoted as P -1 and P n+1 , n is the number of equal parts in step 6, 80, such as Fig.12 shown.

[0029] Step 8: Small area P m (m=-1~40) to perform affine transformation. m Perform an affine transformation. For P m The coordinates of the graphics contained in , using their corresponding affine transformation parameters a m , b m , c m , d m , p m , q m , the coordinates of the transformed point are obtained according to the following formula: (2) Calculate P -1 Point-time utilization coefficient within the region a 0 , b 0 , c 0 , d 0 , p 0 , q 0 To calculate, use a n , b n , c n , d n , p n , q n P n+1The points in the area are transformed. The original material distribution diagram line type composition is kept unchanged, and the coordinates of its points are updated to the coordinates after affine transformation. At this point, the material distribution diagram of the actual tire is obtained, such as Fig.13 .

[0030] Through the above steps, the real material distribution map of the tire is obtained, and the simulation analysis based on the mold contour is compared with the actual measurement. Fig.14 As shown in the figure, the simulation analysis using the transformed material distribution map (real material distribution map) is compared with the actual measurement. Fig.15 As shown, Fig.14 The simulation results are quite different from the measured results. Fig.15 It shows that the simulation results are very close to the calculated results, so the subsequent simulation analysis results are likely to be accurate, which proves the effectiveness of this method.

[0031] The above is a description of the embodiments of the present invention. Through the above description of the disclosed embodiments, professionals and technicians in the field can implement or use the present invention. Various modifications to these embodiments will be apparent to professionals and technicians in the field. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will conform to the widest range consistent with the principles and novelties disclosed herein.

Claims

1. A method for obtaining an actual material distribution map for tire performance analysis, characterized in that: The following steps are involved: 1) External contour scanning: Inflate the tire to standard pressure, then deflate it to an internal pressure of 0.01-0.1MPa, use a laser scanner to obtain the tire's external contour and save it as a vector file; 2) Material distribution map drawing: Based on the actual tire section, use CAD software to draw the material distribution map of the tire; 3) Outer contour smoothing: Smooth the outer contour data to eliminate the roughness and obtain a smoothed outer contour curve; 4) Material distribution map smoothing: Smooth the outer contour of the drawn material distribution map to obtain a smoothed material distribution map curve; 5) Mapping curve selection and equal division: Select some continuous curves from the smoothed outer contour curve and material distribution curve respectively for equal division, the number of equal divisions is n, and generate the target curve set and the original curve set; 6) Affine transformation matrix calculation: Calculate the affine transformation matrix based on the target curve node coordinates and the original curve node coordinates; 7) Region division: Generate multiple small regions according to equally divided points based on the mapping curve; 8) Affine transformation: Perform affine transformation on the point coordinates of each small area and update them to the point coordinates of the actual material distribution map.

2. The method according to claim 1, characterized in that Step 4) The smoothing of the inner and outer contours includes: a) Use arc to block the concave part of the groove; b) Use arcs to smooth out the rough curves caused by grooves, decorative lines and font lines.

3. The method according to claim 1, characterized in that The affine transformation matrix in step 6) is calculated by the following formula: ； in x * k , y* k represents the coordinates of the points on the original curve, x k and y k represents the coordinates of the point on the target curve, a k , b k , c k , d k , p k , q k are the affine transformation coefficients.

4. The method according to claim 1, characterized in that The principle of equally dividing the mapping curve in step 7) is that the length of each curve portion is not greater than 0.5 mm, and the number of equally divided portions n is an even number and greater than 30.

5. The method according to claim 1, characterized in that In step 8), the affine transformation is calculated by the following formula: ； in x * m , y* m represents the coordinates of the points on the original curve, x m and y m represents the coordinates of the point on the target curve, a m , b m , c m , d m , p m , q m are the affine transformation coefficients.

6. A system for obtaining a tire actual material distribution map, characterized in that: The system implements the method according to any one of claims 1 to 5, including: Laser scanning module: used to scan the outer contour of the tire and generate a vector file containing the outer contour data; Drawing module: used to import actual cross-section images and draw tire material distribution maps; Smoothing module: smoothing the tire outer contour and material distribution map; Affine transformation module: used to calculate the affine transformation matrix and perform affine transformation operations on small areas; Segmentation module: used to segment the material distribution map into multiple small areas according to the mapping curve; Output module: Output updated actual material distribution map.

7. The system according to claim 6, characterized in that The affine transformation module comprises: The node extraction submodule is used to extract the coordinates of equally divided nodes of the mapping curve; A matrix calculation submodule, used to calculate the affine transformation matrix based on the node coordinates; The coordinate transformation submodule is used to perform coordinate affine transformation of small areas.

8. The system according to claim 6, characterized in that The output module can export the updated material distribution map into multiple formats, including dxf, svg or other compatible formats, to facilitate subsequent simulation analysis.

9. A computer-readable storage medium having a computer program or instruction stored thereon, characterized in that: When the computer program or instruction is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or instruction is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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