An additive interlocking path planning method for multi-robot arc additive process
By adopting the incremental interlocking forming path planning method in multi-robot collaborative arc additive manufacturing, the problem of low forming quality in overlapping areas is solved, and high performance and efficient printing of overlapping places is achieved.
Patent Information
- Application Number
- CN202510230300.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2025-05-06
- Estimated Expiration
- 2045-02-28
AI Technical Summary
When multi-robot collaborative arc additive manufacturing, the forming quality of the overlap area is low, which is prone to defects such as poor overlap, overfilling or underfilling, pores, etc., resulting in the formation of the formed parts requiring a lot of machining, reducing material utilization and printing efficiency.
A method of increasing interlocking forming path planning is proposed. By setting the overlap strategy, bias distance and bias period, the overlap area forms an incrementing interlocking forming structure to avoid forming defects, and select appropriate path planning methods based on the geometric characteristics of each sub-region.
Effectively eliminate the forming defects in the overlap area during collaborative printing of multiple robots, improve the performance and material utilization of overlapping points, and improve printing efficiency.
Smart Images
Figure CN119703269B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of arc additive manufacturing, and in particular to an additive interlocking path planning method for a multi-robot arc additive process. Background Art
[0002] Additive manufacturing technology is a bottom-up, layer-by-layer, high-speed manufacturing technology driven by discrete data and combined with real-time intelligent control and printing process performance regulation. Arc fuse additive manufacturing technology uses the welding arc as a heat source to melt the synchronously supplied wire, and under the guidance of the printing path, it accumulates layer by layer on the substrate to manufacture metal parts. Compared with other additive manufacturing technologies, arc additive manufacturing technology has the advantages of large forming size, high material utilization rate and low manufacturing cost.
[0003] As the "brain" of additive manufacturing technology, process planning software includes key links such as model layering and slicing, path planning, process planning, and machine code export. The path planning method determines the overall forming quality of the entire part. For medium / large complex parts, the use of multi-robot collaborative arc additive manufacturing methods can further improve the printing efficiency of parts. However, when multi-robot collaborative printing is used, defects are prone to form at the overlap of multiple areas, including poor overlap, overfilling or underfilling, porosity, etc. As the number of printing layers increases, defects will gradually accumulate in the overlap area. The formed parts often require a lot of machining, which reduces material utilization and printing efficiency.
[0004] A review of the current status of research at home and abroad shows that multiple robots are mainly used to improve printing efficiency. In the rapid and efficient manufacturing of large and complex components, arc additive manufacturing with multiple robots shows great application prospects. Although the collaboration of multiple robots can significantly improve the printing efficiency of large components, the forming quality of the overlap of the components is low, which is prone to poor overlap, excessive deposition of materials at the overlap, and reduced surface flatness. The existing research and development does not consider the forming quality and forming performance of the overlap area when multiple machines collaborate. To address this problem, the patent of this invention proposes an additive interlocking forming path planning method. Summary of the invention
[0005] The present invention proposes an incremental interlocking forming path planning method, the purpose of which is to eliminate the forming defects of the overlapping area during multi-machine collaborative printing; by setting the overlapping strategy, offset distance and offset period, the overlapping area forms an incremental interlocking forming structure, avoiding the forming defects that are easily formed by the fixed overlapping strategy; on the other hand, each sub-area can select a different path planning method, so as to better match the geometric characteristics of the sub-area.
[0006] In order to achieve the above object, the present invention is specifically implemented through the following technical solutions:
[0007] An additive interlocking path planning method for a multi-robot arc additive process comprises the following steps:
[0008] S1. Use slicing software to decompose the three-dimensional model in STL format into a series of two-dimensional contour polygons; determine the number and position of the initial segmentation lines in the polygons according to the number of multi-robots, and the position and number of the initial segmentation lines in each layer of polygons are consistent;
[0009] S2. Establishing the actual segmentation line, offsetting the initial segmentation line according to the offset mode, offset distance and offset period, and obtaining the actual segmentation line position of each layer;
[0010] S3, constructing the segmentation polygon corresponding to each robot according to the actual segmentation line in each layer of polygons, and forming the offset overlap area in the overlapping area of each segmentation polygon of adjacent layers; performing Boolean intersection operation on each segmentation polygon and the polygon of the layer to obtain the actual path planning area corresponding to each robot in each layer;
[0011] S4. For each actual path planning area of each layer, a suitable path planning method is selected according to the geometric features, and the actual forming path of each actual path planning area is obtained by planning.
[0012] Further on the basis of the above scheme, in step S1, the initial segmentation line is the set of all adjacent robot center lines
[0013] Further on the basis of the above scheme, in step S2, the number of robots is N, N≥2; the initial dividing line divides the polygon into N parts, and the actual dividing line is a set of initial dividing lines synchronously and cyclically biased in the direction of each robot in sequence, each layer of polygon is biased once, and a total of N biases for N layers of polygons is regarded as a bias cycle.
[0014] Further on the basis of the above scheme, in step S2, in step S2, the setting of the offset distance adopts a random method and is randomly selected within the range of 0-10mm.
[0015] On the basis of the above scheme, in step S3, the segmentation polygon is an outer line parallel to the initial segmentation line after adding 50 mm outwards on the basis of the highest point coordinate, the lowest point coordinate, the rightmost coordinate, and the leftmost coordinate of the polygon, and the rectangle enclosed by each outer line and the actual segmentation line is the segmentation polygon;
[0016] The actual path planning area is the portion where the polygon overlaps with each segmentation polygon after Boolean operations are performed on the segmentation polygons and the polygons, and that is the actual path planning area.
[0017] Further on the basis of the above solution, in step S3, a spacing distance is set between the segmented polygons, and the spacing distance is the same as the overlapping distance of the robot working path.
[0018] Further on the basis of the above scheme, in step S4, the path planning method of the actual forming path adopts a single path of a "Z"-shaped path and a contour offset path or a composite path of the two combinations.
[0019] The technical solution of the present invention first determines the number of areas that need to be decomposed in each layer of polygonal slices according to the reachable space of each robot and the number of robots, and then determines the overlap offset strategy and offset period of the multi-robot path offset overlap area. The overlap areas of two adjacent layers are staggered by offsetting the overlap area, and the next layer printing path can cover the overlap area of the previous layer, so that the two adjacent layers are interlocked in a "zipper"-like manner in the printing direction, thereby improving the performance of the overlap and eliminating the forming defects of the overlap. At the same time, after determining the actual printing areas of each layer, different path planning methods can be selected for each area, which can further optimize the surface forming quality of parts with complex shapes.
[0020] The interlocking path planning method for multi-robot arc additive process of the present invention has important practical application value and theoretical guiding significance for improving the forming quality of the overlap zone during multi-robot collaborative printing. By adopting this method, the forming defects of the overlap zone can be eliminated, thereby improving material utilization and printing efficiency. The zipper interlocking method can be integrated into the metal additive manufacturing process planning software as a module for multi-machine collaborative printing, which is crucial to improving the strength of domestic process planning software. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 is a flow chart of the path planning method of the present invention;
[0022] Figure 2 This is a schematic diagram of path planning according to the first embodiment of the present invention;
[0023] Figure 3 Model slicing and contour polygon extraction according to the second embodiment of the present invention;
[0024] Figure 4 Determine the actual segmentation lines of multiple regions of the four robots in one offset cycle according to the second embodiment of the present invention;
[0025] Figure 5 This is a schematic diagram of the segmentation polygon and the actual path planning area according to the second embodiment of the present invention;
[0026] Figure 6 A path diagram of each actual path planning area in the second embodiment of the present invention;
[0027] Figure 7 This is a schematic diagram of partition offset for collaborative printing by three robots according to the third embodiment of the present invention. DETAILED DESCRIPTION
[0028] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0029] like Figures 1 to 7 As shown, an additive interlocking path planning method for a multi-robot arc additive process of the present invention comprises the following steps:
[0030] S1. Use slicing software to decompose the three-dimensional model in STL format into a series of two-dimensional contour polygons with different height values; determine the number and position of the initial segmentation lines within the polygon according to the number of multi-robots, and the position and number of the initial segmentation lines of each layer of polygons are consistent.
[0031] The slice thickness value needs to be set when slicing. The slice thickness of arc additive manufacturing is generally between 1-5mm. After slicing, each polygon has a different coordinate Z value, that is, a different height value. The Z values between any two adjacent polygons are equal. The number of robots is not less than 2, and the initial dividing line is the set of the center lines of all adjacent robots, that is, the equally spaced dividing line in the direction of each robot's position.
[0032] S2. Set up the actual segmentation line, offset the initial segmentation line according to the offset mode, offset distance and offset cycle, and obtain the actual segmentation line position of each layer. The number of robots is N, N≥2, and N is an integer; the initial segmentation line divides the polygon into N parts, and the actual segmentation line is the initial segmentation line set synchronously and cyclically offset in the direction of each robot in sequence, and each layer of polygon is offset once, with a total of N offsets for N layers of polygons as a bias cycle, that is, N layers are one cycle.
[0033] In a specific embodiment, when the number of robots is 2, the polygon is decomposed into two parts, so the actual segmentation line is divided by left, right or up, down staggered cyclic offset, and the offset period is 2. When the number of robots is 3, the part polygon is decomposed into 3 parts, and the overlap area is offset in the printing area of each robot, and the offset period is 3. When the number of robots is 4, the actual segmentation line is divided by clockwise or counterclockwise staggered cyclic offset in the four quadrants of the plane, and the offset period is 4.
[0034] The setting of the offset distance adopts a random method and is randomly selected within the range of 0-10mm. Multi-machine types require customized offset methods and offset distances. The actual dividing line position of each layer is determined according to the offset cycle, and different interlocking structures are formed in combination with the number of offset cycles. Preferably, a different offset distance is selected for each layer to ensure that the offset distances of any two adjacent layers are different, thereby eliminating the influence of the overlap on the forming to the greatest extent.
[0035] S3. Each layer of polygons constructs the segmentation polygons corresponding to each robot according to the actual segmentation line, and the overlapping areas of the segmentation polygons of adjacent layers form offset overlap areas; each segmentation polygon is subjected to Boolean intersection operation with the polygons of the layer to obtain the actual path planning area corresponding to each robot in each layer.
[0036] Preferably, in step S3, the segmentation polygon is an outer rectangular outline set by adding 50 mm outwards on the basis of the highest point coordinate, the lowest point coordinate, the rightmost coordinate and the leftmost coordinate of the polygon outline, and the polygon enclosed by the outer rectangular outline and each actual segmentation line is the segmentation polygon;
[0037] The actual path planning area is the portion where the polygon overlaps with each segmentation polygon after Boolean operations are performed on the segmentation polygons and the polygons, and that is the actual path planning area.
[0038] Preferably, the spacing distance between the segmented polygons is consistent with the overlap distance of the path, both of which are preset values, generally between 3-10 mm in arc additive manufacturing. A distance needs to be set between two adjacent segmented polygons to avoid overlapping of the forming paths when planning the paths, which in turn leads to excessive accumulation of materials during printing.
[0039] S4. For each actual path planning area of each layer, a suitable path planning method is selected according to the geometric features, and the actual forming path of each actual path planning area is obtained by planning.
[0040] Preferably, in step S4, the path planning method of the actual forming path adopts a single path of a "Z"-shaped path and a contour offset path, or a composite path of the two combinations.
[0041] Embodiment 1 of the present invention is an additive interlocking path planning method for a multi-robot arc additive process using a dual-robot solution, such as Figure 2 As shown, the steps include:
[0042] S1. Use slicing software to decompose the three-dimensional model in STL format into two-dimensional contour rectangles with different height values; the number of multi-robots is 2, and the position of the initial segmentation line is determined to be at the center line and the number is 1 according to the number of robots.
[0043] S2. According to the offset mode and offset distance of the actual segmentation line relative to the initial segmentation line, and the offset period of the multiple layers of actual segmentation lines, the actual segmentation line of each layer is established. Figure 2 From a plane perspective, the actual segmentation line can be offset alternately by left and right bias, or by upper and lower bias. The bias cycle is 2, and the actual segmentation line of each layer is obtained by cyclic bias. Figure 2 The bias period in can also be 4, with four as a group of cycles.
[0044] The offset distance is randomly selected within 0-10mm, and a different offset distance is selected for each layer to ensure that the offset distances of any two adjacent layers are different, thereby eliminating the influence of the overlap on the forming to the greatest extent. In this embodiment, the offset distance of the first layer is 2mm, that is, the actual dividing line is 2mm to the left of the initial dividing line; the offset distance of the second layer is 4mm, that is, the actual dividing line is 4mm to the right of the initial dividing line; the offset distance of the third layer is 5mm, that is, the actual dividing line is 5mm to the left of the initial dividing line; the offset distance of the fourth layer is 1.5mm, that is, the actual dividing line is 1.5mm to the right of the initial dividing line.
[0045] S3. Each layer of polygons constructs the segmentation polygons corresponding to each robot according to the actual segmentation line, that is, the rectangles ①② on the left and right sides of each layer in step S3. The overlapping areas of the segmentation polygons between adjacent layers form an offset overlap area, which is the overlapping area between the actual segmentation lines of the two layers.
[0046] Perform a Boolean intersection operation on each segmentation polygon and the polygon of the layer to obtain the actual path planning area corresponding to each segmentation polygon of each layer.
[0047] The segmentation polygon is formed by adding 50 mm to the outer rectangular outline on the basis of the highest point coordinate, the lowest point coordinate, the rightmost coordinate, and the leftmost coordinate of the polygon. The polygon enclosed by the outer rectangular outline and the actual segmentation lines is the segmentation polygon.
[0048] The actual path planning area is the portion where the polygon overlaps with each segmentation polygon after Boolean operations are performed on the segmentation polygons and the polygons, and that is the actual path planning area.
[0049] S4. For each actual path planning area of each layer, a suitable path planning method is selected according to the geometric features to plan and obtain the actual forming path of each actual path planning area. In the first embodiment, the actual path planning areas are all rectangular, and either a "Z"-shaped path or a contour offset path can be used. Figure 2 In the figure, the actual path planning areas on both sides of the 1st, 2nd, and 4th layers all use connected "Z"-shaped paths, the left side of the 3rd layer uses a connected "Z"-shaped path, and the right side uses a contour offset path.
[0050] Embodiment 2 of the present invention is an interlocking path planning method for multi-robot arc additive process using a four-robot solution, such as Figures 3 to 6 As shown, the steps include:
[0051] S1. Use slicing software to decompose the three-dimensional model in STL format into two-dimensional contour polygons with different height values; the number of multi-robots is 4, and the number of initial segmentation lines in the polygon is determined to be 2. The positions of the initial segmentation lines are the X-direction center line and the Y-direction center line, and the positions and numbers of the initial segmentation lines of each layer of polygons are consistent.
[0052] S2, such as Figure 4 As shown, the actual dividing line is divided by clockwise or counterclockwise staggered cyclic offset according to the four quadrants of the plane within one cycle, that is, the actual dividing line is divided by staggered offset in the upper right, upper left, lower left, and upper right in sequence, the offset cycle is 4, the offset distance is randomly selected within 0-10mm, and a different offset distance is selected for each layer.
[0053] S3. Each layer of polygons constructs the segmentation polygons corresponding to each robot according to the actual segmentation line, and the overlapping areas of the segmentation polygons between adjacent layers form offset overlap areas; each segmentation polygon is subjected to Boolean intersection operation with the polygons of the layer to obtain the actual path planning area corresponding to each segmentation polygon of each layer.
[0054] The segmentation polygon is to set the outer rectangular outline by adding 50mm to the highest point coordinate, the lowest point coordinate, the rightmost coordinate, and the leftmost coordinate of the polygon outline. The polygon surrounded by the outer rectangular outline and each actual segmentation line is the segmentation polygon. Each layer of polygons is divided into 4 segmentation polygons. After performing Boolean operations on each segmentation polygon and polygon, the part that overlaps with each segmentation polygon is the actual path planning area.
[0055] S4. For each actual path planning area of each layer, a suitable path planning method is selected according to the geometric features to plan and obtain the actual formed path of each actual path planning area. In the second embodiment, each actual path planning area corresponding to the robot selects a corresponding path planning method, such as Figure 6 As shown, robot No. 1 selects the contour offset path, robot No. 2 selects the unconnected "Z" shaped path, robot No. 3 selects the compound path, and robot No. 4 selects the connected "Z" shaped path.
[0056] like Figure 7 As shown, embodiment three of the present invention is an additive interlocking path planning method for a multi-robot arc additive process using a three-robot solution; in step S1, the initial dividing line is composed of three rays with a common intersection; in step S2, the initial dividing line is biased toward a robot each time, and the initial dividing line is biased three times within a bias cycle to obtain three actual dividing line positions at different positions, and each bias divides the layer of polygons into segmentation polygons corresponding to each robot.
[0057] The present invention proposes an incremental interlocking path planning method for a multi-robot arc additive process. First, the number of areas that need to be decomposed is determined based on the accessible space of each robot and the number of robots. Then, the overlap bias strategy and bias cycle of the overlap of the multi-robots are determined. The overlap areas of the two adjacent layers are staggered by offsetting the overlap areas. The next layer of printing path can cover the overlap area of the previous layer, so that the two adjacent layers are interlocked in a "zipper"-like manner in the printing direction, improving the performance of the overlap and eliminating the above-mentioned forming defects. After determining the printing area of each layer, different path planning methods can be selected for each area, which can further optimize the surface forming quality for parts with complex shapes.
[0058] The specific embodiments of the present invention are merely explanations of the present invention and are not limitations of the present invention. After reading this specification, those skilled in the art may make modifications to the embodiments without any creative contribution as needed. However, such modifications are protected by the patent law as long as they are within the scope of the claims of the present invention.
Claims
1. A method for planning interlocking paths for multi-robot arc additive processes, characterized in that: The following steps are involved: S1. Decompose the three-dimensional model in STL format into a series of two-dimensional contour polygons using slicing software; determine the number and position of initial segmentation lines within the polygons according to the number of multi-robots; S2. Establishing the actual segmentation line, offsetting the initial segmentation line according to the offset mode, offset distance and offset period, and obtaining the actual segmentation line position of each layer; S3, each layer of polygons constructs a segmentation polygon corresponding to each robot according to the actual segmentation line, and the overlapping areas of the segmentation polygons of adjacent layers form an offset overlap area; Perform a Boolean intersection operation on each segmentation polygon and the polygon of the layer to obtain the actual path planning area corresponding to each robot in each layer; S4. For each actual path planning area of each layer, a suitable path planning method is selected according to the geometric features, and the actual forming path of each actual path planning area is obtained by planning.
2. The method for interlocking path planning for multi-robot arc additive process according to claim 1, characterized in that: In step S1, the initial segmentation line is the set of all adjacent robot center lines.
3. The method for planning an additive interlocking path for a multi-robot arc additive process according to claim 2, characterized in that: In step S2, the number of robots is N, N≥2; the initial dividing line divides the polygon into N parts, and the actual dividing line is a set of initial dividing lines synchronously and cyclically biased in the direction of each robot in sequence, each layer of polygon is biased once, and a total of N biases for N layers of polygons is a bias cycle.
4. The method for planning an additive interlocking path for a multi-robot arc additive process according to claim 1, characterized in that: In step S2, the offset distance is set by a random method and is randomly selected within the range of 0-10 mm.
5. The method for interlocking path planning for multi-robot arc additive process according to claim 1, characterized in that: In step S3, the segmentation polygon is an outer rectangular outline set by adding 50 mm outwards on the basis of the highest point coordinates, the lowest point coordinates, the rightmost coordinates, and the leftmost coordinates of the polygon outline. The polygon enclosed by the outer rectangular outline and each actual segmentation line is the segmentation polygon; The actual path planning area is the portion where the polygon overlaps with each segmentation polygon after Boolean operations are performed on the segmentation polygons and the polygons, and that is the actual path planning area.
6. The method for interlocking path planning for multi-robot arc additive process according to claim 1, characterized in that: In step S3, a spacing distance is set between the segmented polygons, and the spacing distance is the same as the overlapping distance of the robot working path.
7. The method for interlocking path planning for multi-robot arc additive process according to claim 1, characterized in that: In step S4, the path planning method of the actual forming path adopts a single path of a "Z"-shaped path and a contour offset path or a composite path of the two.
Citation Information
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