Scan line NFP generation method for irregular sheet metal part nesting interference detection

Abstract

The application discloses a scanning line NFP generation method for irregular sheet metal part layout interference detection, and belongs to the field of irregular sheet metal part optimization blanking in a mechanical machining production process. The method comprises the following specific steps: step 1, inputting scanning line information of the irregular sheet metal part; step 2, generating a peripheral NFP; step 3, generating a feasible region located in the peripheral NFP; step 4, removing the feasible region located in the peripheral NFP from the peripheral NFP; and step 5, outputting an NFP result. When the scanning line is used to express the contour of the irregular sheet metal part, the complete interference region between two contours is obtained through offline calculation, the contour interference detection in the layout process can be efficiently realized, the method has the characteristics of high operation efficiency, can be used for quickly and effectively detecting the irregular sheet metal part interference in the layout process, and can be applied in multiple scenes.

Description

Technical Field

[0001] This invention belongs to the field of optimized blanking of irregular sheet metal parts in mechanical processing, and more specifically, relates to a method for generating scan lines (NFP) for interference detection of irregular sheet metal parts. Background Technology

[0002] Due to the advantages of sheet metal parts, such as light weight, high strength, low cost, and good mass production performance, their market usage rate is constantly increasing, leading to intensified competition among enterprises. Companies are eager to improve their market competitiveness by reducing production costs and increasing production efficiency. For irregular sheet metal parts, traditional manual nesting methods are no longer sufficient to meet the production needs of enterprises. Enterprises urgently require a more efficient nesting method. Irregular sheet metal part nesting refers to arranging a given number and type of irregularly contoured sheet metal parts on a given motherboard according to the optimal nesting scheme. The most significant characteristic of the irregular sheet metal part nesting problem is that the arranged sheet metal parts have irregular contours. When solving the irregular sheet metal part nesting problem, the process of determining whether interference occurs between the contours of different sheet metal parts involves complex geometric calculations. Different methods of interference judgment are used for different sheet metal part contour representations, requiring different computation times and exhibiting varying robustness.

[0003] In existing research on the layout problem of irregular sheet metal parts, scan lines are a commonly used method for representing the contours of irregular sheet metal parts. In the existing technology, when using scan lines to represent the contours of irregular sheet metal parts, the contour interference detection in the layout process is achieved by judging whether each scan line between different contours overlaps. This method is robust, but has low detection efficiency, and the detection needs to be performed in real time during the layout process, which seriously reduces the computational efficiency of the layout algorithm. Summary of the Invention

[0004] To address the need for improvements in existing technologies, this invention provides a scan-line NFP generation method for interference detection in irregular sheet metal part layout, used to calculate the complete interference region between two contours. Its purpose is to efficiently achieve contour interference detection during the layout process by obtaining the complete interference region between two contours offline when using scan lines to represent the contours of irregular sheet metal parts.

[0005] To achieve the above objectives, the present invention discloses the following technical solution:

[0006] Step 1: Input the scan line information of irregular sheet metal part A and irregular sheet metal part B; the scan line information refers to all scan lines located inside the irregular sheet metal part in the y-axis direction with a given scan accuracy.

[0007] Step 2: Generate the peripheral NFP; First, select the reference point of the irregular sheet metal part B. Keeping the position of the scan line of the irregular sheet metal part A constant, translate the scan line of the irregular sheet metal part B to a position where the reference point of the irregular sheet metal part B is located at the starting height of the peripheral NFP; then, keeping the height of the scan line of the irregular sheet metal part B fixed, translate the scan line of the irregular sheet metal part B from infinity in the negative x-axis direction along the positive x-axis direction until it reaches the first position where the scan line of the irregular sheet metal part A and the scan line of the irregular sheet metal part B have one and only point contact. Mark the corresponding reference point of the irregular sheet metal part B as the horizontal left endpoint of the height; keep the height of the scan line of the irregular sheet metal part B fixed, and translate the scan line of the irregular sheet metal part B from infinity in the positive x-axis direction towards the x-axis... The axis is translated in the negative direction until the first position where the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B have one and only point contact is reached. The reference point of the corresponding irregular sheet metal part B is marked as the horizontal right endpoint of the height. Then, the height of the scan line of irregular sheet metal part B is increased sequentially and the above steps are repeated. That is, the height of the scan line of irregular sheet metal part B is increased by one scan unit in sequence, and the left and right endpoints at the corresponding heights are calculated and marked according to the above process until the calculation and marking of the left and right endpoints corresponding to the termination height of the peripheral NFP are completed. The left endpoint and the corresponding right endpoint of each height marked in the cycle are connected to form the scan line of the peripheral NFP at the corresponding height. The scan lines corresponding to all heights together constitute the peripheral NFP.

[0008] Step 3: Generate feasible regions located inside the outer NFP; the feasible region refers to the area where the scan line of irregular sheet metal part B does not interfere with the scan line of irregular sheet metal part A when the reference point of irregular sheet metal part B is located in the region; traverse each scan height of the outer NFP and calculate all feasible positions for each scan height; determine whether the feasible position is a single-point feasible position. If the feasible position is a single-point feasible position, add the feasible position twice to the container. If the feasible position is a continuous feasible position, add the x-coordinate and y-coordinate of the feasible position once to the container and mark it as an element of the container. The container is a collection of elements or groups of elements representing feasible positions; arrange all elements in the container in ascending order according to their corresponding x-coordinates; after arrangement, form a new element group by combining every two elements in sequence without repetition; each new element group in the container represents a feasible region in the corresponding scan height; after traversing all scan heights of the outer NFP, obtain all feasible regions located inside the outer NFP.

[0009] Step 4: Remove the feasible region inside the outer NFP obtained in Step 3 from the outer NFP; traverse all scan heights of the outer NFP and determine whether there is a feasible region in the scan height. If there is, remove the feasible region in the scan height. Otherwise, directly proceed to the next scan height for judgment until all scan heights of the outer NFP are traversed to obtain the outer NFP after removing the feasible region inside the outer NFP.

[0010] Step 5: Take the peripheral NFP obtained in Step 4 after removing the feasible region inside the peripheral NFP as the final NFP result and output it.

[0011] Preferably, the outer NFP start height and outer NFP end height in step 2 are defined as follows: the outer NFP start height refers to the height of the reference point of the irregular sheet metal part B when the maximum scan height of the irregular sheet metal part B coincides with the minimum scan height of the irregular sheet metal part A; the outer NFP end height refers to the height of the reference point of the irregular sheet metal part B when the minimum scan height of the irregular sheet metal part B coincides with the maximum scan height of the irregular sheet metal part A.

[0012] Preferably, the specific process for calculating all feasible positions at a certain scan height of the peripheral NFP in step 3 is as follows: For a given scan height h of the peripheral NFP, the scan line located at the given scan height h of the peripheral NFP is denoted as scan. h The scan line of irregular sheet metal part B is translated along the y-axis until the reference point of irregular sheet metal part B is located at height h. Keeping the height of the scan line of irregular sheet metal part B constant, it is translated from infinity in the negative x-axis direction to the positive x-axis direction until the first position where the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B have one and only point contact. Then, keeping the height of the scan line of irregular sheet metal part B constant, it is translated ε units in the positive x-axis direction, where ε is a positive number greater than 0 and much less than 1. After translation, it is checked whether there is interference between the scan lines of irregular sheet metal part A and irregular sheet metal part B. If there is no interference, it is further determined whether the reference point of irregular sheet metal part B at that position is located on the scan line. h At the right endpoint; if the reference point of the irregular sheet metal part B corresponding to this position is located at scan hAt the right endpoint, the calculation of feasible positions in the scanning height h ends; otherwise, the reference point of the irregular sheet metal part B corresponding to that position is marked as a feasible position. Then, the scanning line of the irregular sheet metal part B is translated α units in the positive x direction, where α is the value shown in formula (1). After translation, the scanning line of the irregular sheet metal part A and the scanning line of the irregular sheet metal part B are checked again for interference until the scanning lines of the irregular sheet metal part A and the scanning lines of the irregular sheet metal part B are separated from each other, and the reference point of the irregular sheet metal part B corresponding to that position is located in the scan. h When the right endpoint is reached, the calculation of feasible positions in the scan height ends; if interference exists, the scan line of irregular sheet metal part B is shifted β units in the positive x-axis direction, where β refers to the minimum distance that the scan line of irregular sheet metal part B needs to be shifted in the positive x-axis direction so that the scan lines of irregular sheet metal part A and irregular sheet metal part B are separated from each other. After the shift, the scan lines of irregular sheet metal part A and irregular sheet metal part B are checked again for interference until the scan lines of irregular sheet metal part A and irregular sheet metal part B are separated from each other, and the reference point of irregular sheet metal part B corresponding to this position is located at the scan... h When the right endpoint is reached, the calculation of feasible positions in that scan height ends; after traversing each scan height of the outer NFP, all feasible positions located inside the outer NFP are obtained;

[0013]

[0014] In formula (1), h A h represents the total actual scan height of irregular sheet metal part A. B s represents the total actual scan height of irregular sheet metal part B. j s represents the total number of scan lines contained in the j-th real scan height of the irregular sheet metal part A. k x represents the total number of scan lines contained in the k-th real scan height of the irregular sheet metal part B. 0 ju Let x be the x-coordinate of the left endpoint of the u-th scan line in the j-th real scan height of the irregular sheet metal part A. 1 kv Let x be the x-coordinate of the right endpoint of the v-th scan line in the k-th real scan height of the irregular sheet metal part B. 1 ju Let x be the x-coordinate of the right endpoint of the u-th scan line in the j-th real scan height of the irregular sheet metal part A. 0 kv Let x and y be the left endpoint of the v-th scan line in the k-th real scan height of the irregular sheet metal part B. 0 j0 The y-coordinate of the left endpoint of the first scan line in the j-th real scan height of the irregular sheet metal part A, y 0k0 The y-coordinate is the left endpoint of the first scan line in the kth actual scan height of the irregular sheet metal part B; the actual scan height of the irregular sheet metal part refers to the scan height where at least one scan line exists.

[0015] Preferably, the specific process for determining whether a feasible position is a single-point feasible position in step 3 is as follows: For a given feasible position, firstly, the scan line of the irregular sheet metal part B is translated to a position where the reference point of the irregular sheet metal part B coincides with the feasible position; then, keeping the height of the scan line of the irregular sheet metal part B unchanged, the scan line of the irregular sheet metal part B is translated ε units in the positive x-axis direction; where ε is a positive number greater than 0 and much less than 1; after translation, it is detected whether there is interference between the scan line of the irregular sheet metal part A and the scan line of the irregular sheet metal part B; if there is interference, the feasible position is marked as right-side interference; otherwise, the feasible position is marked as... The right side is feasible; then, the scan line of irregular sheet metal part B is translated to a position where the reference point of irregular sheet metal part B coincides with the feasible position; keeping the height of the scan line of irregular sheet metal part B unchanged, the scan line of irregular sheet metal part B is translated ε units in the negative x-axis direction; where ε is a positive number greater than 0 and much less than 1; after translation, it is detected whether there is interference between the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B; if there is interference, the feasible position is marked as left-side interference, otherwise the feasible position is marked as left-side feasible; if the feasible position is both left-side and right-side interference, then the feasible position is marked as a single-point feasible position.

[0016] Preferably, the specific process of removing the feasible region in a certain scan height in step 4 is as follows: For a scan height h in the peripheral NFP where a feasible region exists, firstly, store the left endpoint of the scan line of the peripheral NFP corresponding to the height h into container C. h Then, iterate through each feasible region corresponding to the height h, arrange the feasible regions in ascending order according to the left endpoint x-coordinate, and store the left and right endpoints of each feasible region into container C. h Then, the right endpoint of the scan line of the peripheral NFP corresponding to the height h is stored in container C. h ; Container C h All elements are combined in pairs without repetition to form new groups of elements, which are then stored in container C in sequence. h The container C h Each new element group represents an NFP scan line segment after removing the feasible region.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention provides a scanning line NFP generation method for interference detection in irregular sheet metal layout. When using scanning lines to represent the contour of irregular sheet metal parts, the complete interference area between two contours is obtained through offline calculation, which can efficiently realize contour interference detection in the layout process and has the characteristics of high computational efficiency.

[0019] 2. The present invention provides a scanning line NFP generation method for interference detection of irregular sheet metal parts. During the interference detection process of the layout process, while maintaining the scanning line position of irregular sheet metal part A, the scanning line of irregular sheet metal part B is moved. Based on the positional relationship between the reference point of irregular sheet metal part B and the scanning line of irregular sheet metal part A, the feasible area between irregular sheet metal part B and irregular sheet metal part A is obtained. This enables accurate calculation of the NFP of irregular sheet metal parts for complex irregular sheet metal parts, and has good algorithm stability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the scan lines of the irregular sheet metal part according to the present invention;

[0021] Figure 2 This is a schematic diagram of the starting and ending heights of the peripheral NFP of the present invention;

[0022] Figure 3 This is a schematic diagram of the left and right endpoints of the i-th height of the peripheral NFP of the present invention;

[0023] Figure 4 This is a schematic diagram illustrating a feasible location within the peripheral NFP of the present invention;

[0024] Figure 5 The outline of the irregular sheet metal part A of this invention;

[0025] Figure 6 The outline of the irregular sheet metal part B of this invention;

[0026] Figure 7 This is a scan line representation of the irregular sheet metal part A of the present invention;

[0027] Figure 8 This is a scan line representation of the irregular sheet metal part B of the present invention;

[0028] Figure 9 This is the peripheral NFP result diagram generated by the present invention;

[0029] Figure 10 This is the final NFP result diagram generated by the present invention;

[0030] Figure 11 This is a diagram of the layout scheme obtained by the present invention using existing technology;

[0031] Figure 12This is a diagram of a layout scheme obtained using the technology provided by this invention.

[0032] Figure 13 This is a flowchart of the scanning line NFP generation method for interference detection of irregular sheet metal parts according to the present invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0034] This invention provides a scanning line NFP generation method for interference detection in irregular sheet metal part layout. When the scanning line represents the contour of an irregular sheet metal part, the complete interference region between two contours is obtained through offline calculation. This method can efficiently realize contour interference detection in the layout process and is applied to calculate the complete interference region between two complex irregular sheet metal part contours. It features high computational efficiency and good algorithm stability.

[0035] Specifically, such as Figure 13 As shown, this invention provides a method for generating scan lines NFP (NoFitPolygon) for interference detection of irregular sheet metal parts, which includes the following steps:

[0036] Step 1: Input the scan line information for irregular sheet metal part A and irregular sheet metal part B; for example... Figure 1 As shown, scan line information refers to all scan lines located inside irregular sheet metal parts with a given scan precision in the y-axis direction.

[0037] Step 2: Generate the peripheral NFP; First, select the reference point of the irregular sheet metal part B. Keeping the position of the scan line of the irregular sheet metal part A constant, translate the scan line of the irregular sheet metal part B to a position where the reference point of the irregular sheet metal part B is located at the starting height of the peripheral NFP; then, keeping the height of the scan line of the irregular sheet metal part B fixed, translate the scan line of the irregular sheet metal part B from infinity in the negative x-axis direction along the positive x-axis direction until it reaches the first position where the scan line of the irregular sheet metal part A and the scan line of the irregular sheet metal part B have one and only point contact. Mark the corresponding reference point of the irregular sheet metal part B as the horizontal left endpoint of the height; keep the height of the scan line of the irregular sheet metal part B fixed, and translate the scan line of the irregular sheet metal part B from infinity in the positive x-axis direction towards the x-axis... The axis is translated in the negative direction until the first position is reached where the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B have one and only point contact. The reference point of the corresponding irregular sheet metal part B is marked as the horizontal right endpoint of the height. Then, the height of the scan line of irregular sheet metal part B is increased sequentially and the above steps are repeated. That is, the height of the scan line of irregular sheet metal part B is increased by one scan unit in sequence, and the left and right endpoints at the corresponding heights are calculated and marked according to the above process until the calculation and marking of the left and right endpoints corresponding to the termination height of the peripheral NFP are completed. The left endpoint and the corresponding right endpoint of each height marked in the cycle are connected to form the scan line of the peripheral NFP at the corresponding height. The scan lines corresponding to all heights together constitute the peripheral NFP.

[0038] Step 3: Generate feasible regions located inside the outer NFP; a feasible region refers to the area where the scan lines of irregular sheet metal part B and irregular sheet metal part A do not interfere when the reference point of irregular sheet metal part B is located in this region; traverse each scan height of the outer NFP and calculate all feasible positions for each scan height; determine whether a feasible position is a single-point feasible position. If it is, add two feasible positions to the container. If it is a continuous feasible position, add the x and y coordinates of the feasible position to the container and mark it as an element of the container. The container is a collection of elements or groups of elements representing feasible positions; sort all elements in the container in ascending order according to their corresponding x coordinates; after sorting, form a new element group by combining every two elements in sequence without repetition; each new element group in the container represents a feasible region in the corresponding scan height; after traversing all scan heights of the outer NFP, obtain all feasible regions located inside the outer NFP.

[0039] Step 4: Remove the feasible region inside the outer NFP obtained in Step 3 from the outer NFP; traverse all scan heights of the outer NFP and determine whether there is a feasible region in the scan height. If there is, remove the feasible region in the scan height. Otherwise, directly proceed to the next scan height for judgment until all scan heights of the outer NFP are traversed to obtain the outer NFP after removing the feasible region inside the outer NFP.

[0040] Step 5: Take the peripheral NFP obtained in Step 4 after removing the feasible region inside the peripheral NFP as the final NFP result and output it.

[0041] in, Figure 2 A schematic diagram showing the starting height and ending height of the outer NFP is provided. Figure 3 A schematic diagram showing the left endpoint and the right endpoint of the i-th height of the outer NFP is shown; Figure 4 A schematic diagram of a feasible location inside the peripheral NFP is shown.

[0042] The working principle of the present invention will be further described below with reference to specific embodiments: This embodiment takes two irregular sheet metal parts from the Swims example in the benchmark problem provided by the European Interest Group on Sheet Forming Problems (ESICUP) as an example. The scan line NFP generation process between the two irregular sheet metal parts is as follows:

[0043] First, the vertex information of irregular sheet metal parts A and B, represented by scan lines in this embodiment, is given in Tables 1 and 2. After translating irregular sheet metal parts A and B so that their lowest point is at y-coordinate 0, the drawn irregular sheet metal part A is shown in Tables 1 and 2. Figure 5 As shown, the irregular sheet metal part B is drawn. Figure 6 As shown. In this embodiment, irregular sheet metal part A is a fixed irregular sheet metal part, and irregular sheet metal part B is an irregular sheet metal part that can be translated in both the horizontal and vertical directions. Figure 7 and Figure 8 The standardized scan line representations for irregular sheet metal parts A and B involved in this embodiment are given. Scan line standardization refers to converting the actual y-coordinate values ​​of each scan line into the corresponding scan height index. For example, all scan lines at the first scan height have their y-coordinate values ​​set to 0, all scan lines at the second scan height have their y-coordinate values ​​set to 1, and so on for the remaining scan heights. Before scan line standardization, the actual y-coordinate interval between two adjacent scan lines is set to 40.0.

[0044] Table 1. Vertex coordinates of irregular sheet metal part A

[0045]

[0046]

[0047] Table 2. Vertex coordinates of irregular sheet metal part B

[0048]

[0049]

[0050] A preferred embodiment of the present invention provides a method for generating scan line NFPs for interference detection of irregular sheet metal parts, comprising the following steps:

[0051] Step 1: Input the scan line information of irregular sheet metal part A and irregular sheet metal part B; scan line information refers to all scan lines located inside the irregular sheet metal part in the y-axis direction with a given scan precision; in this embodiment, the input scan line information of irregular sheet metal part A is as follows: Figure 7 As shown; in this embodiment, the scan line information of the irregular sheet metal part B is input as follows: Figure 8 As shown.

[0052] Step 2: Generate the peripheral NFP; First, select a reference point for irregular sheet metal part B. Keeping the position of the scan line of irregular sheet metal part A constant, translate the scan line of irregular sheet metal part B to a position where the reference point of irregular sheet metal part B is located at the starting height of the peripheral NFP; then, keeping the height of the scan line of irregular sheet metal part B fixed, translate the scan line of irregular sheet metal part B from infinity in the negative x-axis direction along the positive x-axis direction until it reaches the first position where the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B have one and only point contact. Mark the corresponding reference point of irregular sheet metal part B as the horizontal left endpoint of the height; keeping the height of the scan line of irregular sheet metal part B fixed, translate the scan line of irregular sheet metal part B from infinity in the positive x-axis direction to the negative x-axis direction. Until the first position where the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B have one and only point contact is reached, the reference point of the corresponding irregular sheet metal part B is marked as the horizontal right endpoint of the height; then, the height of the scan line of irregular sheet metal part B is increased sequentially and the above steps are repeated, that is, the height of the scan line of irregular sheet metal part B is increased by one scan unit in turn, and the left and right endpoints at the corresponding heights are calculated and marked according to the above process, until the calculation and marking of the left and right endpoints corresponding to the termination height of the peripheral NFP are completed; the left endpoint and the corresponding right endpoint of each height marked in the loop are connected to form the scan line of the peripheral NFP at the corresponding height; the scan lines corresponding to all heights together constitute the peripheral NFP; the peripheral NFP generated in this embodiment is as follows. Figure 9 As shown.

[0053] Step 3: Generate feasible regions located inside the outer NFP; a feasible region refers to the area where the scan lines of irregular sheet metal part B and irregular sheet metal part A do not interfere when the reference point of irregular sheet metal part B is located in this region; traverse each scan height of the outer NFP and calculate all feasible positions for each scan height; determine whether a feasible position is a single-point feasible position. If it is, add two feasible positions to the container. If it is a continuous feasible position, add the x and y coordinates of the feasible position to the container and mark it as an element of the container. The container is a collection of elements or groups of elements representing feasible positions; sort all elements in the container in ascending order according to their corresponding x coordinates; after sorting, form a new element group by combining every two elements in sequence without repetition; each new element group in the container represents a feasible region in the corresponding scan height; after traversing all scan heights of the outer NFP, obtain all feasible regions located inside the outer NFP.

[0054] Step 4: Remove the feasible region inside the outer NFP obtained in Step 3 from the outer NFP; traverse all scan heights of the outer NFP and determine whether there is a feasible region in the scan height. If there is, remove the feasible region in the scan height. Otherwise, directly proceed to the next scan height for judgment until all scan heights of the outer NFP are traversed to obtain the outer NFP after removing the feasible region inside the outer NFP.

[0055] Step 5: Take the peripheral NFP obtained in Step 4, after removing the feasible region inside the peripheral NFP, as the final NFP result and output it. In this embodiment, the output final NFP result is as follows: Figure 10 As shown.

[0056] In step 2, the starting height and ending height of the peripheral NFP are defined as follows: The starting height of the peripheral NFP refers to the height of the reference point of the irregular sheet metal part B when the maximum scan height of the irregular sheet metal part B coincides with the minimum scan height of the irregular sheet metal part A; the ending height of the peripheral NFP refers to the height of the reference point of the irregular sheet metal part B when the minimum scan height of the irregular sheet metal part B coincides with the maximum scan height of the irregular sheet metal part A.

[0057] The specific process for calculating all feasible positions at a certain scan height of the peripheral NFP in step 3 is as follows: For a given scan height h of the peripheral NFP, the scan line located at the given scan height h of the peripheral NFP is denoted as scan. hThe scan line of irregular sheet metal part B is translated along the y-axis until the reference point of irregular sheet metal part B is located at height h. Keeping the height of the scan line of irregular sheet metal part B constant, it is translated from infinity in the negative x-axis direction to the positive x-axis direction until the first position where the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B have one and only point contact. Then, keeping the height of the scan line of irregular sheet metal part B constant, it is translated ε units in the positive x-axis direction, where ε is a positive number greater than 0 and much less than 1. After translation, it is checked whether there is interference between the scan lines of irregular sheet metal part A and irregular sheet metal part B. If there is no interference, it is further determined whether the reference point of irregular sheet metal part B at that position is located on the scan line. h At the right endpoint; if the reference point of the irregular sheet metal part B corresponding to this position is located at scan h At the right endpoint, the calculation of feasible positions in the scanning height h ends; otherwise, the reference point of the irregular sheet metal part B corresponding to that position is marked as a feasible position. Then, the scanning line of the irregular sheet metal part B is translated α units in the positive x direction, where α is the value shown in formula (1). After translation, the scanning line of the irregular sheet metal part A and the scanning line of the irregular sheet metal part B are checked again for interference until the scanning lines of the irregular sheet metal part A and the scanning lines of the irregular sheet metal part B are separated from each other, and the reference point of the irregular sheet metal part B corresponding to that position is located in the scan. h When the right endpoint is reached, the calculation of feasible positions in the scan height ends; if interference exists, the scan line of irregular sheet metal part B is shifted β units in the positive x-axis direction, where β refers to the minimum distance that the scan line of irregular sheet metal part B needs to be shifted in the positive x-axis direction so that the scan lines of irregular sheet metal part A and irregular sheet metal part B are separated from each other. After the shift, the scan lines of irregular sheet metal part A and irregular sheet metal part B are checked again for interference until the scan lines of irregular sheet metal part A and irregular sheet metal part B are separated from each other, and the reference point of irregular sheet metal part B at this position is located in the scan. h When the right endpoint is reached, the calculation of feasible positions in that scan height ends; after traversing each scan height of the outer NFP, all feasible positions located inside the outer NFP are obtained;

[0058]

[0059] In formula (1), h A h represents the total actual scan height of irregular sheet metal part A. B s represents the total actual scan height of irregular sheet metal part B. j s represents the total number of scan lines contained in the j-th real scan height of the irregular sheet metal part A. kx represents the total number of scan lines contained in the k-th real scan height of the irregular sheet metal part B. 0 ju Let x be the x-coordinate of the left endpoint of the u-th scan line in the j-th real scan height of the irregular sheet metal part A. 1 kv Let x be the x-coordinate of the right endpoint of the v-th scan line in the k-th real scan height of the irregular sheet metal part B. 1 ju Let x be the x-coordinate of the right endpoint of the u-th scan line in the j-th real scan height of the irregular sheet metal part A. 0 kv Let x and y be the left endpoint of the v-th scan line in the k-th real scan height of the irregular sheet metal part B. 0 j0 The y-coordinate of the left endpoint of the first scan line in the j-th real scan height of the irregular sheet metal part A, y 0 k0 The y-coordinate of the left endpoint of the first scan line in the k-th real scan height of the irregular sheet metal part B; the real scan height of the irregular sheet metal part refers to the scan height where at least one scan line exists.

[0060] The specific process for determining whether a feasible position is a single-point feasible position in step 3 is as follows: For a given feasible position, firstly, the scan line of the irregular sheet metal part B is translated to a position where the reference point of the irregular sheet metal part B coincides with the feasible position; then, keeping the height of the scan line of the irregular sheet metal part B unchanged, the scan line of the irregular sheet metal part B is translated ε units in the positive x-axis direction; where ε is a positive number greater than 0 and much less than 1; after translation, it is checked whether there is interference between the scan line of the irregular sheet metal part A and the scan line of the irregular sheet metal part B; if there is interference, the feasible position is marked as right-side interference, otherwise the feasible position is marked as right-side interference. Feasible; then, translate the scan line of irregular sheet metal part B to a position where the reference point of irregular sheet metal part B coincides with the feasible position; keep the height of the scan line of irregular sheet metal part B unchanged, and translate the scan line of irregular sheet metal part B in the negative x-axis direction by ε units; where ε is a positive number greater than 0 and much less than 1; after translation, check whether there is interference between the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B; if there is interference, mark the feasible position as left interference, otherwise mark the feasible position as left feasible; if the feasible position is both left and right interference, mark the feasible position as single-point feasible position.

[0061] The specific process of removing feasible regions in a certain scan height in step 4 is as follows: For a scan height h in the peripheral NFP where a feasible region exists, firstly, store the left endpoint of the scan line of the corresponding peripheral NFP in height h into container C. hThen, iterate through each feasible region at height h, sorting them by their left endpoint x-coordinate from smallest to largest, and store the left and right endpoints of each feasible region into container C. h Then, the right endpoint of the scan line of the outer NFP corresponding to height h is stored in container C. h ; Container C h All elements are combined in pairs without repetition to form new groups of elements, which are then stored in container C in sequence. h Container C h Each new element group represents an NFP scan line segment after removing the feasible region.

[0062] To verify the efficiency of the method provided by this invention, the Shirts case of the ESICP benchmark problem was used as a test case. The layout data obtained by the method provided by this invention was compared with the layout data obtained by existing technologies. The irregular sheet metal parts information included in the case is shown in Table 2. The basic scanning accuracy R of the irregular sheet metal parts expressed by the scan lines is... b The value was set to 0.16, and the resulting layout is shown in Table 3. The layout diagram obtained using existing technology is shown below. Figure 11 As shown, the layout scheme obtained using the technology provided by this invention is illustrated in the diagram below. Figure 12 As shown.

[0063] As shown in Table 3, compared with the prior art, the method provided by the present invention has significantly improved the calculation efficiency while ensuring the sorting effect, which proves the effectiveness of the method provided by the present invention.

[0064] Table 2 Example Information

[0065]

[0066] Table 3. Layout Results

[0067]

[0068] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for generating scan line NFPs for interference detection of irregular sheet metal parts, characterized in that, It includes the following steps: Step 1: Input the scan line information of irregular sheet metal part A and irregular sheet metal part B; the scan line information refers to the information of all scan lines filling the interior of the irregular sheet metal part in the y-axis direction with a given scanning accuracy. Step 2: Generate the peripheral NFP; First, select the reference point of the irregular sheet metal part B, keeping the position of the scan line of the irregular sheet metal part A constant, and translate the scan line of the irregular sheet metal part B to a position where the reference point of the irregular sheet metal part B is located at the starting height of the peripheral NFP; then, keeping the height of the scan line of the irregular sheet metal part B fixed, translate the scan line of the irregular sheet metal part B from infinity in the negative x-axis direction along the positive x-axis direction until it reaches the point where the scan line of the irregular sheet metal part A and the scan line of the irregular sheet metal part B first contact, and mark the corresponding reference point of the irregular sheet metal part B as the horizontal left endpoint of the height; make the scan line of the irregular sheet metal part B... With the tracing height fixed, the scan line of irregular sheet metal part B is translated from infinity in the positive x-axis direction to the negative x-axis direction until it reaches the point where the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B first come into contact. The reference point of the corresponding irregular sheet metal part B is marked as the horizontal right endpoint of the height. Then, the height of the scan line of irregular sheet metal part B is increased sequentially and the above steps are repeated. That is, the height of the scan line of irregular sheet metal part B is increased by one scan unit sequentially, and the left and right endpoints at the corresponding heights are calculated and marked according to the above process until the calculation and marking of the left and right endpoints corresponding to the outer NFP termination height are completed. Connect the left endpoint of each height marked during the loop with the corresponding right endpoint to form the scan line of the peripheral NFP at the corresponding height; the scan lines corresponding to all heights together constitute the peripheral NFP. Step 3: Generate feasible regions located inside the outer NFP; the feasible region refers to the area where the scan line of irregular sheet metal part B does not interfere with the scan line of irregular sheet metal part A when the reference point of irregular sheet metal part B is located in the region; traverse each scan height of the outer NFP and calculate all feasible positions for each scan height; determine whether the feasible position is a single-point feasible position. If the feasible position is a single-point feasible position, add the feasible position twice to the container. If the feasible position is a continuous feasible position, add the x-coordinate and y-coordinate of the feasible position once to the container and mark it as an element of the container. The container is a collection of elements or groups of elements representing feasible positions; arrange all elements in the container in ascending order according to their corresponding x-coordinates; after arrangement, form a new element group by combining every two elements in sequence without repetition; each new element group in the container represents a feasible region in the corresponding scan height; after traversing all scan heights of the outer NFP, obtain all feasible regions located inside the outer NFP. Step 4: Remove the feasible region inside the outer NFP obtained in Step 3 from the outer NFP; traverse all scan heights of the outer NFP and determine whether there is a feasible region in the scan height. If there is, remove the feasible region in the scan height. Otherwise, directly proceed to the next scan height for judgment until all scan heights of the outer NFP are traversed to obtain the outer NFP after removing the feasible region inside the outer NFP. Step 5: Take the peripheral NFP obtained in Step 4 after removing the feasible region inside the peripheral NFP as the final NFP result and output it.

2. The method for generating scan line NFPs for interference detection of irregular sheet metal parts according to claim 1, characterized in that, In step 2, the outer NFP start height and outer NFP end height are defined as follows: the outer NFP start height refers to the height of the reference point of the irregular sheet metal part B when the maximum scan height of the irregular sheet metal part B coincides with the minimum scan height of the irregular sheet metal part A; the outer NFP end height refers to the height of the reference point of the irregular sheet metal part B when the minimum scan height of the irregular sheet metal part B coincides with the maximum scan height of the irregular sheet metal part A.

3. The method for generating scan line NFPs for interference detection of irregular sheet metal parts according to claim 1, characterized in that, In step 3, the specific process of calculating all feasible positions at a given scan height of the peripheral NFP is as follows: For a given scan height h of the peripheral NFP, the scan line located at the given scan height h of the peripheral NFP is denoted as scan. h ; Translate the scan line of irregular sheet metal part B along the y-axis until the reference point of irregular sheet metal part B is located at height h; keeping the height of the scan line of irregular sheet metal part B unchanged, translate the scan line of irregular sheet metal part B from infinity in the negative x-axis direction to the positive x-axis direction until it reaches the point where the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B first contact; then, keeping the height of the scan line of irregular sheet metal part B unchanged, translate the scan line of irregular sheet metal part B in the positive x-direction by ε units, where ε is a positive number greater than 0 and much less than 1; after translation, check whether there is interference between the scan lines of irregular sheet metal part A and irregular sheet metal part B; if there is no interference, further determine whether the reference point of irregular sheet metal part B at this position is located on the scan line. h At the right endpoint; if the reference point of the irregular sheet metal part B corresponding to this position is located at scan h At the right endpoint, the calculation of feasible positions in the scanning height h ends; otherwise, the reference point of the irregular sheet metal part B corresponding to that position is marked as a feasible position. Then, the scanning line of the irregular sheet metal part B is translated α units in the positive x direction, where α is the value shown in formula (1). After translation, the scanning line of the irregular sheet metal part A and the scanning line of the irregular sheet metal part B are checked again for interference until the scanning line of the irregular sheet metal part A and the scanning line of the irregular sheet metal part B are separated from each other, and the reference point of the irregular sheet metal part B corresponding to that position is located in the scan. h When the right endpoint is reached, the calculation of feasible positions in the scan height ends; if interference exists, the scan line of irregular sheet metal part B is shifted β units in the positive x-axis direction, where β refers to the minimum distance that the scan line of irregular sheet metal part B needs to be shifted in the positive x-axis direction so that the scan lines of irregular sheet metal part A and irregular sheet metal part B are separated from each other. After the shift, the scan lines of irregular sheet metal part A and irregular sheet metal part B are checked again for interference until the scan lines of irregular sheet metal part A and irregular sheet metal part B are separated from each other, and the reference point of irregular sheet metal part B corresponding to this position is located at the scan... h When the right endpoint is reached, the calculation of feasible positions in that scan height ends; after traversing each scan height of the outer NFP, all feasible positions located inside the outer NFP are obtained; （1）； The range of values ​​for variables j, k, u, and v is: The constraints are: ; In formula (1), h A h represents the total actual scan height of irregular sheet metal part A. B s represents the total actual scan height of irregular sheet metal part B. j s represents the total number of scan lines contained in the j-th real scan height of the irregular sheet metal part A. k Let be the total number of scan lines contained in the k-th real scan height of the irregular sheet metal part B. Let x be the x-coordinate of the left endpoint of the u-th scan line in the j-th real scan height of the irregular sheet metal part A. Let x be the x-coordinate of the right endpoint of the v-th scan line in the k-th real scan height of the irregular sheet metal part B. Let x be the x-coordinate of the right endpoint of the u-th scan line in the j-th real scan height of the irregular sheet metal part A. Let x be the x-coordinate of the left endpoint of the v-th scan line in the k-th real scan height of the irregular sheet metal part B. The y-coordinate value of the left endpoint of the first scan line in the j-th real scan height of the irregular sheet metal part A. The y-coordinate value is the left endpoint of the first scan line in the kth actual scan height of the irregular sheet metal part B; the actual scan height of the irregular sheet metal part refers to the scan height where there is at least one scan line.

4. The method for generating scan line NFPs for interference detection of irregular sheet metal parts according to claim 1, characterized in that, In step 3, the specific process of determining whether a feasible location is a single-point feasible location is as follows: For a given feasible position, firstly, the scan line of irregular sheet metal part B is translated to a position where the reference point of irregular sheet metal part B coincides with the feasible position; then, keeping the height of the scan line of irregular sheet metal part B unchanged, the scan line of irregular sheet metal part B is translated ε units in the positive x-axis direction; where ε is a positive number greater than 0 and much less than 1; after translation, it is detected whether there is interference between the scan line of irregular sheet metal part A and the scan line of irregular sheet metal part B; if interference exists, the feasible position is marked as right-side interference, otherwise the feasible position is marked as right-side feasible; then the scan line of irregular sheet metal part B is... The tracing line is shifted to a position where the reference point of the irregular sheet metal part B coincides with the feasible position; the height of the scan line of the irregular sheet metal part B remains unchanged, and the scan line of the irregular sheet metal part B is shifted ε units in the negative x-axis direction; where ε is a positive number greater than 0 and much less than 1; after the shift, it is detected whether there is interference between the scan line of the irregular sheet metal part A and the scan line of the irregular sheet metal part B; if there is interference, the feasible position is marked as left-side interference, otherwise the feasible position is marked as left-side feasible; if the feasible position is both left-side and right-side interference, the feasible position is marked as a single-point feasible position.

5. The method for generating scan line NFPs for interference detection of irregular sheet metal parts according to claim 1, characterized in that, In step 4, the specific process of removing the feasible region at a certain scanning height is as follows: For a scan height h of a feasible region within the peripheral NFP, first store the left endpoint of the scan line of the peripheral NFP corresponding to height h into container C. h Then, iterate through each feasible region corresponding to the height h, arrange the feasible regions in ascending order according to the left endpoint x-coordinate, and store the left and right endpoints of each feasible region into container C. h Then, the right endpoint of the scan line of the peripheral NFP corresponding to the height h is stored in container C. h ; Container C h All elements are combined in pairs without repetition to form new groups of elements, which are then stored in container C in sequence. h The container C h Each new element group represents an NFP scan line segment after removing the feasible region.

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