Dual-device collaborative 3D printing method and system

Abstract

The application discloses a kind of 3D printing method and system of double equipment cooperation, belong to 3D printing field, the mortise and tenon polygon is generated in the interface of collaborative printing component, by the printing unit of mortise and tenon polygon is alternately assigned to different equipment, so that the printing component between two equipment is overlapped and engaged layer by layer, guarantee the structural strength of collaborative printing component. By dividing the irregular figure geometric boundary to generate sample point, the sample point is generated by using the sample point to generate the tessellation polygon, the sample point in the tessellation polygon is searched and sorted, all the tessellation polygon and mortise and tenon polygon in the irregular figure are connected and offset, constitute two closed curves for two printing equipment, these curves only make a turn in the X axis direction of figure, meet the path continuity requirement of 3D printing, reduce the collision risk in printing process, can be adapted to the topological change of complex hole structure, avoid the printing path mutation problem of adjacent printing layer.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a dual-device collaborative 3D printing method and system. Background Technology

[0002] 3D printed concrete technology is a novel intelligent construction method that uses robotic arms, gantry cranes, and other printing equipment to extrude quick-setting concrete, thereby constructing building structures. This technology helps reduce the manpower required in the construction process and improves the level of intelligence in the construction industry. However, due to the following reasons, it remains difficult to construct large-scale buildings and structures with openings.

[0003] First, the building volume that 3D printing technology can achieve is limited by the mobility and printing range of the printing equipment. Therefore, the floor area of ​​a building that a single device can print is very limited. Currently, the common approach in the industry is to use mobile devices or mobile tracks to improve the mobility of the printing equipment. However, these added devices can only move in one direction and cannot expand the working range of the equipment in the entire floor space.

[0004] Secondly, 3D printing concrete technology requires a continuous printing path, meaning each layer's printing path must form a single, continuous closed loop to ensure smooth and continuous concrete extrusion. However, structures with holes disrupt this continuity. To print holes using a single device, each layer must first complete the printing on one side of the hole, then stop extruding concrete, wait for the print head to move to the other side of the hole, and then continue extruding. This process results in noticeable defects (such as excessive or insufficient material extrusion) at the points where extrusion stops and resumes, affecting print quality.

[0005] In summary, how to realize large-scale, perforated buildings or structures is an area that 3D printing concrete technology urgently needs to explore.

[0006] Collaborative printing can help solve the printability problem of large-scale, porous concrete structures, but current collaborative printing methods still have three main problems: weak connectivity, easy collision, and difficulty in modification.

[0007] Firstly, current collaborative printing methods used in the field of 3D printed concrete employ point-to-point junctions at the interface between the printed components from two printers. This means the printing paths of the two machines do not intersect or overlap, but rather only come into close proximity at specific points. While this path planning method helps minimize the probability of collisions between the printing machines, the point-to-point junction results in a very weak connection between the two printed components. Therefore, components printed using this method cannot meet the structural requirements of practical engineering projects.

[0008] Secondly, current printing path planning methods for collaborative equipment suffer from a high probability of collisions. In construction engineering, concrete structures typically include both external surfaces and internal supports. To complete these structures in a single printing process, the printing path needs to zigzag multiple times at both ends of the slice. The more times the path zigzags within the same unit of time, the greater the risk of collisions.

[0009] Furthermore, architectural 3D printing needs to meet the requirements of practical use and also requires structural optimization to reduce material usage and carbon emissions during construction. These functional requirements and optimization methods often result in many non-standard, perforated structural components in buildings. During 3D printing, the topological relationships of each slice of these components are constantly changing. This requires that the paths generated for each slice adapt to the constantly changing slice boundaries, which brings great difficulty to the programming of printing paths.

[0010] In summary, how to design the printing path to improve the interlocking between the printed components of the two machines, ensure the smoothness and safety of the printing process, and match the topology of complex structures are problems that have not yet been solved in the current collaborative 3D printing technology for concrete. Summary of the Invention

[0011] This invention provides a dual-device collaborative 3D printing method and system to solve the problems of weak connection, easy collision and difficulty in change in existing device collaborative printing methods.

[0012] A first aspect of the present invention provides a dual-device collaborative 3D printing method, comprising the following steps:

[0013] A 3D printing model of the structure to be printed is generated, and the 3D printing model is divided and sliced ​​to obtain a first graphic boundary line for printing by the first robotic arm and a second graphic boundary line for printing by the second robotic arm.

[0014] Extract the boundary line segment at the intersection of the first graphic boundary line and the second graphic boundary line, convert the boundary line segment into a polygon, divide the polygon into two polygons, and then alternately assign the two polygons to the first robotic arm and the second robotic arm according to the printing layer order to form a mortise and tenon polygon;

[0015] Divide the first and second graphic boundary lines into m sample points, generate m associated Thiessen polygons using the m sample points, sort the m sample points, and connect the sorting results one by one with the Thiessen polygons and the assigned tenon and mortise polygons in the manner of perpendicular bisectors.

[0016] The tandem Thiessen polygon and mortise and tenon polygon are offset as a whole by half the width of the printing line to obtain the printing paths of the first robotic arm and the second robotic arm.

[0017] Optionally, in one embodiment of the present invention, the 3D printed model is divided and sliced ​​to obtain a first graphic boundary line for printing by a first robotic arm and a second graphic boundary line for printing by a second robotic arm, including:

[0018] The 3D printed model is divided to obtain a first model for printing with a first robotic arm and a second model for printing with a second robotic arm. The first model and the second model are sliced ​​to obtain a first graphic boundary line of the first model and a second graphic boundary line of the second model.

[0019] Optionally, in one embodiment of the present invention, the first graphic boundary line and the second graphic boundary line are divided into m sample points, m Thiessen polygons associated with the m sample points are generated using the m sample points, the m sample points are sorted, and the sorting results are concatenated one by one with the Thiessen polygons corresponding to the sample points and the assigned tenon and mortise polygons in the manner of perpendicular bisectors, including the following steps:

[0020] Unify the starting point positions of the first and second graphic boundary lines, divide the first and second graphic boundary lines into m segments, generate m sample points, use the m sample points to generate the Thiessen polygon within the boundary line, and number the Thiessen polygon. The number of the Thiessen polygon is consistent with the number of the sample point that generated the Thiessen polygon.

[0021] For all printed layers, select any sample point with the same number as the starting search point, and search within ±45° of the negative Y-axis direction of the starting search point to find sample points that meet the preset connection conditions. After each search, connect the starting search point with the sample point that meets the preset connection conditions.

[0022] The sample points that meet the preset connection conditions are used as new search points to continue the search until there are no sample points that meet the preset connection conditions. All the lines generated during the search process are merged into a continuous multi-segment line.

[0023] Among the unsearched sample points in the same printing layer, find sample points that meet the preset starting conditions and use them as the starting search points for a new round of connection. Starting from the starting search points, start a new round of search along the negative Y-axis to find sample points that meet the preset connection conditions and generate the continuous multi-segment lines.

[0024] The search process is repeated multiple times until all sample points of the current printing layer have been searched and no new continuous polyline can be generated.

[0025] Connect the vertices of all consecutive polylines in the positive Y-axis direction to the nearest sample points on their adjacent consecutive polylines to form all bridging polylines between consecutive polylines;

[0026] Map the connection relationships between all sample points on the continuous polyline and the bridging polyline to the Thiessen polygons corresponding to the sample points, and generate the perpendicular bisector at the intersection of the Thiessen polygons with connection relationships.

[0027] Generate the same perpendicular line as in the previous step on the intersection of the mortise polygon and its adjacent Thiessen polygon.

[0028] Optionally, in one embodiment of the present invention, the preset connection condition is that the absolute value of the slope of the line connecting the sample point and the retrieval point is the largest, and the Thiessen polygon corresponding to the sample point is adjacent to the Thiessen polygon corresponding to the retrieval point.

[0029] Optionally, in one embodiment of the present invention, the preset starting condition is: if there are no sample points in the same printing layer that satisfy the preset connection condition, and there are unsearched sample points in the current printing layer, then among all the remaining sample points, the point with the largest (yk·x) value of its coordinates is found as the starting search point for a new round of connection, where k is the slope.

[0030] A second aspect of the present invention provides a dual-device collaborative 3D printing system, comprising:

[0031] First robotic arm and second robotic arm;

[0032] The generation module is used to generate a 3D printing model of the structure to be printed, and to divide and slice the 3D printing model to obtain a first graphic boundary line for printing by the first robotic arm and a second graphic boundary line for printing by the second robotic arm.

[0033] The extraction module is used to extract the boundary line segments at the intersection of the first graphic boundary line and the second graphic boundary line, convert the boundary line segments into polygons, divide the polygons into two polygons, and then alternately assign the two polygons to the first robotic arm and the second robotic arm according to the printing layer order to form a mortise and tenon polygon.

[0034] The connection module is used to divide the first graphic boundary line and the second graphic boundary line into m sample points, generate m associated Thiessen polygons using the m sample points, sort the m sample points, and connect the sorting results one by one with the Thiessen polygons corresponding to the sample points and the assigned tenon and mortise polygons in the manner of perpendicular bisectors.

[0035] The printing module is used to offset the concatenated Thiessen polygon and mortise and tenon polygon by half the width of the printing line to obtain the printing paths of the first robotic arm and the second robotic arm.

[0036] Optionally, in one embodiment of the present invention, the generation module is further configured to divide the 3D printed model to obtain a first model for printing with a first robotic arm and a second model for printing with a second robotic arm, and to slice the first model and the second model to obtain a first graphic boundary line of the first model and a second graphic boundary line of the second model.

[0037] Optionally, in one embodiment of the present invention, the connection module is specifically used for:

[0038] Unify the starting point positions of the first and second graphic boundary lines, divide the first and second graphic boundary lines into m segments, generate m sample points, use the m sample points to generate the Thiessen polygon within the boundary line, and number the Thiessen polygon. The number of the Thiessen polygon is consistent with the number of the sample point that generated the Thiessen polygon.

[0039] For all printed layers, select any sample point with the same number as the starting search point, and search within ±45° of the negative Y-axis direction of the starting search point to find sample points that meet the preset connection conditions. After each search, connect the starting search point with the sample point that meets the preset connection conditions.

[0040] The sample points that meet the preset connection conditions are used as new search points to continue the search until there are no sample points that meet the preset connection conditions. All the lines generated during the search process are merged into a continuous multi-segment line.

[0041] Among the unsearched sample points in the same printing layer, find sample points that meet the preset starting conditions and use them as the starting search points for a new round of connection. Starting from the starting search points, start a new round of search along the negative Y-axis to find sample points that meet the preset connection conditions and generate the continuous multi-segment lines.

[0042] The search process is repeated multiple times until all sample points of the current printing layer have been searched and no new continuous polyline can be generated.

[0043] Connect the vertices of all consecutive polylines in the positive Y-axis direction to the nearest sample points on their adjacent consecutive polylines to form all bridging polylines between consecutive polylines;

[0044] Map the connection relationships between all sample points on the continuous polyline and the bridging polyline to the Thiessen polygons corresponding to the sample points, and generate the perpendicular bisector at the intersection of the Thiessen polygons with connection relationships.

[0045] Generate the same perpendicular line as in the previous step on the intersection of the mortise polygon and its adjacent Thiessen polygon.

[0046] Optionally, in one embodiment of the present invention, the preset connection condition is: the absolute value of the slope of the line connecting the sample point and the retrieval point is the largest, and the Thiessen polygon corresponding to the sample point is adjacent to the Thiessen polygon corresponding to the retrieval point.

[0047] Optionally, in one embodiment of the present invention, the preset starting condition is: if there are no sample points in the same printing layer that satisfy the preset connection condition, and there are unsearched sample points in the current printing layer, then among all the remaining sample points, the point with the largest (yk·x) value of its coordinates is found as the starting search point for a new round of connection, where k is the slope.

[0048] The dual-device collaborative 3D printing method and system of this invention have the following beneficial effects:

[0049] 1. From the perspective of structural generation, the method of the present invention enhances the interlocking method between the two printed components, enabling the shared printing area of ​​the two robotic arms to achieve better connection and ensuring the strength of the collaboratively printed components.

[0050] 2. From the perspective of path planning, the method of the present invention ensures that the printing path only retraces once in each layer slice, minimizing the collision probability of the printing equipment. This path planning method can also be used in 3D printing of other materials.

[0051] 3. From the perspective of computational cost, the method of the present invention uses local path generation instead of global path generation to effectively reduce the complexity of printing path generation for irregular graphics and improve the efficiency of printing line generation.

[0052] 4. From the perspective of actual construction, the method of this invention solves the problem of equipment coordination in 3D printing of large building components, and promotes the application of equipment collaborative printing in actual construction projects.

[0053] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0054] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0055] Figure 1 A flowchart illustrating a dual-device collaborative 3D printing method according to an embodiment of the present invention;

[0056] Figure 2 This is the printing process of dual-arm collaborative printing according to an embodiment of the present invention;

[0057] Figure 3This is a schematic diagram of the print path generation process according to an embodiment of the present invention;

[0058] Figure 4 A structural component printed according to an embodiment of the present invention;

[0059] Figure 5 Another structural component printed according to an embodiment of the present invention;

[0060] Figure 6 This is another structural component printed according to an embodiment of the present invention;

[0061] Figure 7 This is a block diagram of a dual-device collaborative 3D printing system according to an embodiment of the present invention. Detailed Implementation

[0062] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0063] Figure 1 This is a flowchart of a dual-device collaborative 3D printing method provided according to an embodiment of the present invention.

[0064] like Figure 1 As shown, this dual-device collaborative 3D printing method includes the following steps:

[0065] In step S101, a 3D printing model of the structure to be printed is generated, and the 3D printing model is divided and sliced ​​to obtain a first graphic boundary line for printing by the first robotic arm and a second graphic boundary line for printing by the second robotic arm.

[0066] In an embodiment of the present invention, firstly, the 3D printed model is divided to obtain a first model for printing with a first robotic arm and a second model for printing with a second robotic arm. Secondly, the first model and the second model are sliced ​​to obtain a first graphic boundary line of the first model and a second graphic boundary line of the second model.

[0067] In step S102, the boundary line segments at the intersection of the first graphic boundary line and the second graphic boundary line are extracted, the boundary line segments are converted into polygons, the polygons are divided into two polygons, and the two polygons are alternately assigned to the first robotic arm and the second robotic arm according to the printing layer order to form a mortise and tenon polygon.

[0068] In an embodiment of the present invention, at the junction of the first model and the second model, the line segment of the graphic boundary line at the junction is transformed into a polygon. The polygon can be a hexagon or other symmetrical polygon. The transformed polygon is then divided into two identical polygons.

[0069] This invention alternately distributes polygonal printing units to different printing devices, so that the printing components of the two devices overlap and interlock layer by layer, ensuring the structural strength of the collaboratively printed components.

[0070] In step S103, the first graphic boundary line and the second graphic boundary line are divided into m sample points. The m sample points are used to generate m associated Thiessen polygons. The m sample points are sorted, and the sorting results are connected one by one with the Thiessen polygons corresponding to the sample points and the assigned tenon and mortise polygons in the manner of perpendicular bisectors.

[0071] In an embodiment of the present invention, step S103 specifically includes the following steps:

[0072] Unify the starting point positions of the first and second graphic boundary lines, divide the first and second graphic boundary lines into m segments, generate m sample points, use the m sample points to generate Thiessen polygons within the boundary lines, and number the Thiessen polygons. The number of the Thiessen polygons is consistent with the number of the sample points that generated the Thiessen polygons.

[0073] For all printed layers, select any sample point with the same number as the starting search point, and search within ±45° of the negative Y-axis direction of the starting search point to find sample points that meet the preset connection conditions. After each search, connect the starting search point with the sample point that meets the preset connection conditions.

[0074] The sample points that meet the preset connection conditions are used as new search points to continue the search until there are no more sample points that meet the preset connection conditions. All the lines generated during the search process are merged into a continuous polyline.

[0075] Find sample points that meet the preset starting conditions among the unsearched sample points in the same printing layer, and use them as the starting search points for a new round of connection. Starting from the starting search points, start a new round of search along the negative Y-axis to find sample points that meet the preset connection conditions and generate continuous multi-segment lines.

[0076] The search process is repeated multiple times until all sample points of the current printing layer have been searched and no new continuous polyline can be generated.

[0077] Connect the vertices of all consecutive polylines in the positive Y-axis direction to the nearest sample points on their adjacent consecutive polylines to form all bridging polylines between consecutive polylines;

[0078] Map the connection relationships between all sample points on the continuous polyline and the bridging polyline to the Thiessen polygons corresponding to the sample points, and generate the perpendicular bisector at the intersection of the Thiessen polygons with connection relationships.

[0079] Generate the same perpendicular line as in the previous step on the intersection of the mortise polygon and its adjacent Thiessen polygon.

[0080] In an embodiment of the present invention, the preset connection conditions are: the absolute value of the slope of the line connecting the sample point and the retrieval point is the largest, and the Thiessen polygon corresponding to the sample point is adjacent to the Thiessen polygon corresponding to the retrieval point.

[0081] In an embodiment of the present invention, the preset starting condition is: if there are no sample points in the same printing layer that satisfy the preset connection condition, and there are unsearched sample points in the current printing layer, then among all the remaining sample points, the point with the largest (yk·x) value of its coordinates is found as the starting search point for a new round of connection, where k is the slope.

[0082] This invention generates sample points by equally dividing irregular geometric boundaries, and then uses these sample points to generate Thiessen polygons. The Thiessen polygons generated by this method can adapt to the topological changes of complex hole structures, avoid the problem of abrupt changes in the printing path of adjacent printing layers, ensure the continuity of the printing path in the Z-axis direction (i.e. the printing direction), and make the printing path meet the self-support requirements of concrete 3D printing.

[0083] By retrieving and sorting the sample points within the Thiessen polygons, the retrieval results can be used to connect all Thiessen polygons and tenon-and-mortise polygons within the irregular shape.

[0084] In step S104, the concatenated Thiessen polygon and mortise and tenon polygon are offset as a whole by half the width of the printing line to obtain the printing paths of the first robotic arm and the second robotic arm. Both paths only make one turnback in the X-axis direction of the graphic, which can not only meet the path continuity requirements of 3D printing, but also minimize the collision risk of any irregular graphic in the printing process.

[0085] Figure 2 This demonstrates the process of generating the print path for one of the print layers in dual-arm collaborative printing. Figure 3 The entire graphic is displayed, combined Figure 2 and Figure 3 The 3D printing method of the present invention will be described in detail below. Figure 3In the diagram, number 1 represents the printing area of ​​the left robotic arm, number 2 represents the printing area of ​​the right robotic arm, number 3 represents the mortise and tenon polygon, which is the area where the left and right robotic arms alternately print. In this printing layer, the left robotic arm prints, and in the next layer, the right robotic arm prints. Number 4 represents the alternating printing area, where the right robotic arm prints in this printing layer, and in the next layer, the left robotic arm prints. Number 5 represents the sample points used to generate the Thiessen polygon, number 6 represents the sample points designated as the starting retrieval point, number 7 represents the sample points designated as retrieval points after the retrieval process begins, number 8 represents the continuous polyline in step 6, number 9 represents the bridging polyline in step 7, and number 10 represents the perpendicular bisector in step 8.

[0086] In one specific embodiment of the present invention, the dual-device collaborative 3D printing method includes the following steps:

[0087] Step 1: Use computer-aided design software to generate a structural model for dual-arm collaborative printing. Based on the actual printing requirements and the working range of the robotic arms, divide the model into two independent parts, which will serve as the printing component models for the two robotic arms respectively.

[0088] Step 2-1: Slice the component model according to the required printing layer height to generate graphic boundary lines, and extract the boundary line segments at the intersection of two components, converting the segments into hexagons (e.g., ...). Figure 3 (as shown in (a)).

[0089] Step 2-2, divide the hexagon into two equal parts. Figure 3 Polygons 3 and 4 in (a) are then alternately assigned to the two robotic arms in the order of the printed layers to form a mortise and tenon polygon. For example, in Figure 3 In the printed layer shown in (a), polygon 3 is assigned to the left robotic arm, while polygon 4 is assigned to the right robotic arm. On the next printed layer, polygon 3 will be assigned to the right robotic arm, and polygon 4 will be assigned to the left robotic arm. This alternating assignment process allows the printed lines of the two robotic arms to overlap and interlock layer by layer, forming a continuous whole.

[0090] Step 3: Unify the starting point position of the boundary line, divide the printed line into m segments, generate m sample points, and use the same numbering logic to number the sample points on each layer of the printed line. Then, use these sample points to generate the Thiessen polygons within the boundary line (e.g., ...). Figure 3 (as shown in (b)), and number the Thiessen polygons, which are consistent with the sample point numbers that generated the Thiessen polygons.

[0091] Step 4-1: For all printed layers, select any control point with the same number as the search point, and search within ±45° of that point in the negative Y-axis direction (e.g., ...). Figure 3As shown in (c), the value of this search range can be adjusted according to actual needs. If the Thiessen polygons are numerous and dense, it is recommended to narrow the search range; otherwise, increase it. The search process needs to find sample points that meet the following two conditions:

[0092] Condition 1: The absolute value of the slope of the line connecting the sample point and the retrieval point is the largest;

[0093] Condition 2: The Thiessen polygon corresponding to the sample point is adjacent to the Thiessen polygon corresponding to the search point.

[0094] Step 4-2: After each search, connect the search point with the sample points that meet the conditions.

[0095] Step 5 introduces a conditional judgment. If a sample point that meets the condition exists in step 4, then that sample point is used as the new search point, and step 4 is repeated. If no point meets the condition, all the lines generated during the search process are merged into a single continuous polyline, and then the process proceeds to step 6.

[0096] Step 6 introduces a conditional judgment. If all sample points of the printed layer have been retrieved and no new connections can be generated, proceed to step 7. If there are still unretrieved points, find the point with the largest (yk·x) value among all remaining sample points as the starting point for a new round of connection retrieval (k is the slope, generally taken as 1, but can be adjusted according to the actual topology of the graphic), and repeat steps 4 to 6 until all control points have been retrieved. Each repetition of step 6 generates a continuous multi-segment line connecting points along the negative Y-axis of the graphic (e.g., ...). Figure 3 (as shown in (d)).

[0097] Step 7: Connect the vertices of all consecutive polylines recorded in Step 6 to the nearest sample points on their adjacent polylines to form all bridging polylines between consecutive polylines (e.g., ...). Figure 3 (as shown in (d)).

[0098] Step 8: Since there is a one-to-one correspondence between the sample points and the Thiessen polygons, by recording the starting point numbers of all the connecting lines, perpendicular bisectors with the same connection relationship can be generated on the intersection line of the two Thiessen polygons corresponding to the starting point. These perpendicular bisectors can be used to connect all the Thiessen polygons into a whole (e.g., ...). Figure 3 (as shown in (e)). At the same time, according to the allocation method in step 2-2, a vertical line connecting to its respective printing range can be generated on each of the tenon and mortise polygons allocated at the intersection.

[0099] Step 9: Integrate all perpendicular lines, Thiessen polygons, and assigned tenon-and-mortise polygons into a single curve set, and offset the entire curve by half the width of the printed line. This will produce a printed line that meets the requirements for one round trip and can be used for equipment collaboration. Figure 3 (as shown in (f)).

[0100] Step 10: Verify the printability of the printed lines. Starting from the starting points of the two paths, calculate the distance between the printing positions on the two printed lines at the same time step by step, with the distance d of the printed lines generating G-code being equally divided. If the distance is shorter than the print head spacing, it means that the model cannot be realized through dual-arm collaboration. It is necessary to return to step 1 to adjust the design scheme, or return to step 3 to increase the subdivision number m of the boundary lines until the printed lines meet the obstacle avoidance requirements.

[0101] Step 11: Based on the equipment operating parameters, convert the printing line into G-code that can be used for 3D printing, allocate it to the two printing devices, and then perform 3D printing.

[0102] The process described in the above embodiments generated the following three types of large-scale, perforated concrete structural members, such as... Figure 4 , Figure 5 , Figure 6 As shown, in Figure 4 , Figure 5 , Figure 6 In the images, (a) are all input graphics, (b) are all print lines, and (c) are all illustrations of the print effect. Figure 4 It is a joint component of the column heads of two concrete columns, which gradually enlarges at the joint and merges into one, forming a doorway-shaped space. Figure 5 This is a prototype of a branched support structure, with a single base that branches outwards in the middle of the structure, eventually forming a larger support plane at the top than at the bottom. This type of structure helps to reduce the amount of material used in large cantilever components. Figure 6 This embodiment is a non-standard concrete support structure, with holes in both the vertical and horizontal directions. This type of configuration is often found in structures obtained through topology optimization. For all three embodiments, the technical solution proposed in this invention can be used to generate the printing path and for dual-device collaborative 3D printing.

[0103] The dual-device collaborative 3D printing method of this invention proposes a method for sorting and connecting Thiessen polygons inside irregular structures, and uses this method to generate printing paths adapted to dual-device collaborative 3D printing. These printing paths can ensure that the printing device performs only one back-and-forth movement in each printing layer, minimizing the collision probability during the collaborative printing process. This enables large-scale, porous concrete structures to be printable, improving the application scenarios and intelligence level of 3D printed concrete technology.

[0104] The dual-device collaborative 3D printing method of this invention can generate overlapping polygonal structures at the junctions of collaboratively printed components. This helps improve the interlocking between the two printed components and solves the problem of weak connections between collaboratively printed 3D components. Simultaneously, this invention ensures that the supporting structure in the concrete component is as perpendicular as possible to the graphic boundary, which enhances the overall structural strength of the collaboratively printed 3D component and increases its potential for use in practical construction projects.

[0105] The dual-device collaborative 3D printing method of this invention uses the equidistant points on the slice boundary as the basis for generating the internal polygonal support structure. This allows the printing lines generated by this invention to satisfy the topological changes that occur in the Z-axis direction (i.e., the printing direction) of components with holes, maintaining the continuity of the upper and lower layer printing paths in terms of configuration and position. This solves the problem of the difficulty in generating printing paths for complex graphics and reduces the complexity of 3D printing path writing.

[0106] The dual-device collaborative 3D printing method of this invention provides a workflow that automatically generates printing paths based on target graphics and evaluates the printability of the paths. This method is applicable to small 3D printing devices such as robotic arms and drones, as well as to collaborative 3D printing of other materials such as clay, polylactic acid, and recyclable plastics, and has broad application value.

[0107] Next, a dual-device collaborative 3D printing system according to an embodiment of the present invention is described with reference to the accompanying drawings.

[0108] Figure 7 This is a block diagram of a dual-device collaborative 3D printing system according to an embodiment of the present invention.

[0109] like Figure 7 As shown, the dual-device collaborative 3D printing system 10 includes: a first robotic arm and a second robotic arm, a generation module 100, an extraction module 200, a connection module 300, and a printing module 400.

[0110] The system comprises the following modules: Generation module 100 generates a 3D printing model of the structure to be printed, divides and slices the 3D printing model to obtain a first graphic boundary line for printing by the first robotic arm and a second graphic boundary line for printing by the second robotic arm. Extraction module 200 extracts the boundary line segments at the intersection of the first and second graphic boundary lines, converts the boundary line segments into polygons, divides each polygon into two equal polygons, and then alternately assigns the two polygons to the first and second robotic arms according to the printing layer order, forming tenon-and-mortise polygons. Connection module 300 divides the first and second graphic boundary lines into m sample points, generates m associated Thiessen polygons using the m sample points, sorts the m sample points, and connects the sorted results one by one with the assigned tenon-and-mortise polygons using a perpendicular bisector. Printing module 400 offsets the connected Thiessen polygons and tenon-and-mortise polygons by half the width of the printing line to obtain the printing paths for the first and second robotic arms.

[0111] Optionally, in one embodiment of the present invention, the generation module 100 is further configured to divide the 3D printed model to obtain a first model for printing with a first robotic arm and a second model for printing with a second robotic arm, and to slice the first model and the second model to obtain a first graphic boundary line of the first model and a second graphic boundary line of the second model.

[0112] Optionally, in one embodiment of the present invention, the connection module 300 is specifically used for:

[0113] Unify the starting point positions of the first and second graphic boundary lines, divide the first and second graphic boundary lines into m segments, generate m sample points, use the m sample points to generate Thiessen polygons within the boundary lines, and number the Thiessen polygons. The number of the Thiessen polygons is consistent with the number of the sample points that generated the Thiessen polygons.

[0114] For all printed layers, select any sample point with the same number as the starting search point, and search within ±45° of the negative Y-axis direction of the starting search point to find sample points that meet the preset connection conditions. After each search, connect the starting search point with the sample point that meets the preset connection conditions.

[0115] The sample points that meet the preset connection conditions are used as new search points to continue the search until there are no more sample points that meet the preset connection conditions. All the lines generated during the search process are merged into a continuous polyline.

[0116] Find sample points that meet the preset starting conditions among the unsearched sample points in the same printing layer, and use them as the starting search points for a new round of connection. Starting from the starting search points, start a new round of search along the negative Y-axis to find sample points that meet the preset connection conditions and generate continuous multi-segment lines.

[0117] The search process is repeated multiple times until all sample points of the current printing layer have been searched and no new continuous polyline can be generated.

[0118] Connect the vertices of all consecutive polylines in the positive Y-axis direction to the nearest sample points on their adjacent consecutive polylines to form all bridging polylines between consecutive polylines;

[0119] Map the connection relationships between all sample points on the continuous polyline and the bridging polyline to the Thiessen polygons corresponding to the sample points, and generate the perpendicular bisector at the intersection of the Thiessen polygons with connection relationships.

[0120] Generate the same perpendicular line as in the previous step on the intersection of the mortise polygon and its adjacent Thiessen polygon.

[0121] Optionally, in one embodiment of the present invention, the preset connection condition is: the absolute value of the slope of the line connecting the sample point and the retrieval point is the largest, and the Thiessen polygon corresponding to the sample point is adjacent to the Thiessen polygon corresponding to the retrieval point.

[0122] Optionally, in one embodiment of the present invention, the preset starting condition is: if there are no sample points in the same printing layer that satisfy the preset connection condition, and there are unsearched sample points in the current printing layer, then among all the remaining sample points, the point with the largest (yk·x) value of its coordinates is found as the starting search point for a new round of connection, where k is the slope.

[0123] It should be noted that the foregoing explanation of the dual-device collaborative 3D printing method embodiment also applies to the dual-device collaborative 3D printing system of this embodiment, and will not be repeated here.

[0124] The dual-device collaborative 3D printing system proposed in this embodiment generates sample points by equally dividing the geometric boundary of an irregular structure. These sample points are then used to generate Thiessen polygons. The Thiessen polygons within the irregular structure are then sorted and connected to generate a printing path suitable for dual-device collaborative 3D printing. This ensures that the printing equipment performs only one back-and-forth motion in each printing layer, minimizing the probability of collisions during collaborative printing. This enables the printability of large-scale, porous concrete structures, improving the application scenarios and intelligence level of 3D printed concrete technology.

[0125] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0126] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0127] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of the invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of the invention pertain.

Claims

1. A dual-device collaborative 3D printing method, characterized in that, Includes the following steps: A 3D printing model of the structure to be printed is generated, and the 3D printing model is divided and sliced ​​to obtain a first graphic boundary line for printing by the first robotic arm and a second graphic boundary line for printing by the second robotic arm. Extract the boundary line segment at the intersection of the first graphic boundary line and the second graphic boundary line, convert the boundary line segment into a polygon, divide the polygon into two polygons, and then alternately assign the two polygons to the first robotic arm and the second robotic arm according to the printing layer order to form a mortise and tenon polygon; Divide the first and second graphic boundary lines into m sample points, generate m associated Thiessen polygons using the m sample points, sort the m sample points, and connect the sorting results one by one with the Thiessen polygons and the assigned tenon and mortise polygons in the manner of perpendicular bisectors. The tandem Thiessen polygon and mortise and tenon polygon are offset as a whole by half the width of the printing line to obtain the printing paths of the first robotic arm and the second robotic arm.

2. The method of claim 1, wherein, The 3D printed model is divided and sliced ​​to obtain a first graphic boundary line for printing by the first robotic arm and a second graphic boundary line for printing by the second robotic arm, including: The 3D printed model is divided to obtain a first model for printing with a first robotic arm and a second model for printing with a second robotic arm. The first model and the second model are sliced ​​to obtain a first graphic boundary line of the first model and a second graphic boundary line of the second model.

3. The method according to claim 1, characterized in that, Divide the first and second graphic boundary lines into m sample points, generate m associated Thiessen polygons using the m sample points, sort the m sample points, and connect the sorted results one by one with the Thiessen polygons and the assigned tenon and mortise polygons using a perpendicular bisector, including the following steps: Unify the starting point positions of the first and second graphic boundary lines, divide the first and second graphic boundary lines into m segments, generate m sample points, use the m sample points to generate the Thiessen polygon within the boundary line, and number the Thiessen polygon. The number of the Thiessen polygon is consistent with the number of the sample point that generated the Thiessen polygon. For all printed layers, select any sample point with the same number as the starting search point, and search within ±45° of the negative Y-axis direction of the starting search point to find sample points that meet the preset connection conditions. After each search, connect the starting search point with the sample point that meets the preset connection conditions. The sample points that meet the preset connection conditions are used as new search points to continue the search until there are no sample points that meet the preset connection conditions. All the lines generated during the search process are merged into a continuous multi-segment line. Among the unsearched sample points in the same printing layer, find sample points that meet the preset starting conditions and use them as the starting search points for a new round of connection. Starting from the starting search points, start a new round of search along the negative Y-axis to find sample points that meet the preset connection conditions and generate the continuous multi-segment lines. The search process is repeated multiple times until all sample points of the current printing layer have been searched and no new continuous polyline can be generated. Connect the vertices of all consecutive polylines in the positive Y-axis direction to the nearest sample points on their adjacent consecutive polylines to form all bridging polylines between consecutive polylines; Map the connection relationships between all sample points on the continuous polyline and the bridging polyline to the Thiessen polygons corresponding to the sample points, and generate the perpendicular bisector at the intersection of the Thiessen polygons with connection relationships. Generate the same perpendicular line as in the previous step on the intersection of the mortise polygon and its adjacent Thiessen polygon.

4. The method according to claim 3, characterized in that, The preset connection conditions are: the absolute value of the slope of the line connecting the sample point and the retrieval point is the largest, and the Thiessen polygon corresponding to the sample point is adjacent to the Thiessen polygon corresponding to the retrieval point.

5. The method according to claim 3, characterized in that, The preset starting condition is: if there are no sample points in the same printing layer that satisfy the preset connection condition, and there are unsearched sample points in the current printing layer, then among all the remaining sample points, the point with the largest (yk·x) value of its coordinates is found as the starting search point for a new round of connection, where k is the slope.

6. A dual-device collaborative 3D printing system, characterized in that, include: First robotic arm and second robotic arm; The generation module is used to generate a 3D printing model of the structure to be printed, and to divide and slice the 3D printing model to obtain a first graphic boundary line for printing by the first robotic arm and a second graphic boundary line for printing by the second robotic arm. The extraction module is used to extract the boundary line segments at the intersection of the first graphic boundary line and the second graphic boundary line, convert the boundary line segments into polygons, divide the polygons into two polygons, and then alternately assign the two polygons to the first robotic arm and the second robotic arm according to the printing layer order to form a mortise and tenon polygon. The connection module is used to divide the first graphic boundary line and the second graphic boundary line into m sample points, generate m associated Thiessen polygons using the m sample points, sort the m sample points, and connect the sorting results one by one with the Thiessen polygons corresponding to the sample points and the assigned tenon and mortise polygons in the manner of perpendicular bisectors. The printing module is used to offset the concatenated Thiessen polygon and mortise and tenon polygon by half the width of the printing line to obtain the printing paths of the first robotic arm and the second robotic arm.

7. The system according to claim 6, characterized in that, The generation module is further used to divide the 3D printed model to obtain a first model for printing with a first robotic arm and a second model for printing with a second robotic arm, and to slice the first model and the second model to obtain a first graphic boundary line of the first model and a second graphic boundary line of the second model.

8. The system according to claim 6, characterized in that, The connection module is specifically used for: Unify the starting point positions of the first and second graphic boundary lines, divide the first and second graphic boundary lines into m segments, generate m sample points, use the m sample points to generate the Thiessen polygon within the boundary line, and number the Thiessen polygon. The number of the Thiessen polygon is consistent with the number of the sample point that generated the Thiessen polygon. For all printed layers, select any sample point with the same number as the starting search point, and search within ±45° of the negative Y-axis direction of the starting search point to find sample points that meet the preset connection conditions. After each search, connect the starting search point with the sample point that meets the preset connection conditions. The sample points that meet the preset connection conditions are used as new search points to continue the search until there are no sample points that meet the preset connection conditions. All the lines generated during the search process are merged into a continuous multi-segment line. Among the unsearched sample points in the same printing layer, find sample points that meet the preset starting conditions and use them as the starting search points for a new round of connection. Starting from the starting search points, start a new round of search along the negative Y-axis to find sample points that meet the preset connection conditions and generate the continuous multi-segment lines. The search process is repeated multiple times until all sample points of the current printing layer have been searched and no new continuous polyline can be generated. Connect the vertices of all consecutive polylines in the positive Y-axis direction to the nearest sample points on their adjacent consecutive polylines to form all bridging polylines between consecutive polylines; Map the connection relationships between all sample points on the continuous polyline and the bridging polyline to the Thiessen polygons corresponding to the sample points, and generate the perpendicular bisector at the intersection of the Thiessen polygons with connection relationships. Generate the same perpendicular line as in the previous step on the intersection of the mortise polygon and its adjacent Thiessen polygon.

9. The system according to claim 8, characterized in that, The preset connection conditions are: the absolute value of the slope of the line connecting the sample point and the retrieval point is the largest, and the Thiessen polygon corresponding to the sample point is adjacent to the Thiessen polygon corresponding to the retrieval point.

10. The system according to claim 8, characterized in that, The preset starting condition is: if there are no sample points in the same printing layer that satisfy the preset connection condition, and there are unsearched sample points in the current printing layer, then among all the remaining sample points, the point with the largest (yk·x) value of its coordinates is found as the starting search point for a new round of connection, where k is the slope.

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