Path planning method, additive manufacturing method and products related thereto

Abstract

The application provides a path planning method, an additive manufacturing method and related products thereof. The path planning method comprises: obtaining structure parameters of a target structure comprising a first structure and a second structure; generating a plurality of printing curved surfaces according to the structure parameters of the target structure, including a first printing curved surface corresponding to the first structure and a second printing curved surface corresponding to the second structure; mapping the first printing curved surface and the second printing curved surface to a two-dimensional plane respectively by using different mapping functions to obtain a first two-dimensional graph and a second two-dimensional graph; planning filling paths in the first two-dimensional graph and the second two-dimensional graph respectively to obtain a first two-dimensional filling path and a second two-dimensional filling path; mapping the first two-dimensional filling path back to the first printing curved surface to obtain a three-dimensional filling path of the first printing curved surface; and mapping the second two-dimensional filling path back to the second printing curved surface to obtain a three-dimensional filling path of the second printing curved surface. The application can reduce the complexity and difficulty of path planning.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material manufacturing, and in particular to a path planning method, an additive manufacturing method and related products thereof. BACKGROUND

[0002] Additive manufacturing technology is relative to subtractive manufacturing. It is based on the principle of layer manufacturing, starting from a digital model, and realizing the manufacturing of three-dimensional solid parts through a layer-by-layer accumulation process rather than a removal process. According to its forming process, it can be divided into Fused Deposition Modeling (FDM), Stereolithography (SLA), Powder Bed Fusion (PBF), etc.

[0003] More and more researches have begun to explore the possibility of additive manufacturing of composite materials. Composite materials are designed by two or more material components, which realize the complementation of the performance of different material components, so as to obtain more superior performance. Especially the composite material with resin as matrix and continuous fiber as reinforcement often has excellent mechanical properties and lightweight characteristics, which makes it have a wide application in advanced manufacturing fields such as aerospace, automobile and ship.

[0004] Based on the idea of combining the advantages of composite materials and additive manufacturing technology, some scholars have proposed the technology of continuous fiber-reinforced polymer additive manufacturing (CFRP-AM). At the same time, the CFRP-AM technology can selectively deposit continuous fiber-reinforced composite materials with spatial distribution, and the manufactured parts often have the characteristics of lightweight and high strength, which has attracted widespread attention from the industry. According to the different forming processes, the CFRP-AM technology can be divided into material extrusion (MEX), directed energy deposition (DED) and laminated objective manufacturing (LOM) etc.

[0005] CFRP-AM technology has very broad application prospects, but due to the short time of the technology and the involvement of many disciplines, such as digital modeling, mechanical and electrical control, material science, etc., there are still many challenges. For example, the existing CFRP-AM manufacturing equipment based on a three-degree-of-freedom motion platform is not suitable for manufacturing complex engineering structures with non-planar fiber laying. In addition, due to the significant mechanical anisotropy of continuous fiber reinforced composites, fiber laying path design is one of the key factors affecting the mechanical properties of CFRP-AM process parts. At the same time, multi-degree-of-freedom motion brings more possibilities for fiber laying path design, but also increases the complexity and difficulty of path planning. SUMMARY

[0006] The application provides a path planning method, an additive manufacturing method and related products thereof, which can reduce the complexity and difficulty of path planning and meet the filling needs of different structures.

[0007] In a first aspect, the application provides a path planning method, comprising:

[0008] obtaining structure parameters of a target structure;

[0009] generating a plurality of printing surfaces according to the structure parameters of the target structure, wherein the target structure comprises different first and second structures, and the plurality of printing surfaces comprises a first printing surface corresponding to the first structure and a second printing surface corresponding to the second structure;

[0010] mapping the first and second printing surfaces to two-dimensional planes using different mapping functions to obtain a first two-dimensional graph and a second two-dimensional graph;

[0011] planning filling paths in the first and second two-dimensional graphs respectively to obtain a first two-dimensional filling path and a second two-dimensional filling path;

[0012] mapping the first two-dimensional filling path back to the first printing surface to obtain a three-dimensional filling path of the first printing surface;

[0013] mapping the second two-dimensional filling path back to the second printing surface to obtain a three-dimensional filling path of the second printing surface.

[0014] Optionally, the planning of the filling paths in the first and second two-dimensional graphs respectively to obtain the first and second two-dimensional filling paths comprises:

[0015] planning the filling paths in the first two-dimensional graph using a full filling method to obtain a first two-dimensional filling path.

[0016] Optionally, the mapping the first and second printing surfaces to two-dimensional planes respectively by using different mapping functions to obtain a first two-dimensional pattern and a second two-dimensional pattern comprises:

[0017] When the first printing surface is a developable surface, mapping the first printing surface to a two-dimensional plane by using an isometric mapping function to obtain a first two-dimensional pattern; or,

[0018] When the first printing surface is not a developable surface, converting the first printing surface into a combination of at least two developable surfaces, and mapping the at least two developable surfaces to a two-dimensional plane respectively by using an isometric mapping function to obtain a first two-dimensional pattern.

[0019] Optionally, the mapping the first and second printing surfaces to two-dimensional planes respectively by using different mapping functions to obtain a first two-dimensional pattern and a second two-dimensional pattern comprises:

[0020] Mapping the second printing surface to a two-dimensional plane by using a conformal mapping function to obtain a second two-dimensional pattern;

[0021] The planning a filling path in the first and second two-dimensional patterns respectively to obtain a first two-dimensional filling path and a second two-dimensional filling path comprises:

[0022] Planning a filling path in the second two-dimensional pattern to obtain a second filling path with a regular pattern.

[0023] Optionally, the target structure is a reinforced shell structure, and the reinforced shell structure comprises a shell and a reinforcing rib located on the surface of the shell.

[0024] The first structure is the shell, and the second structure is the reinforcing rib.

[0025] In a second aspect, the present application provides an additive manufacturing method, comprising:

[0026] The path planning method according to any one of the preceding aspects obtains a three-dimensional filling path of a plurality of printing surfaces of a target structure;

[0027] The three-dimensional filling path of the plurality of printing surfaces is converted into a machine motion trajectory respectively;

[0028] According to the machine motion trajectory, a multi-axis mechanical arm is used to drive an end printing tool located at the end of the multi-axis mechanical arm to print a target material on a printing substrate.

[0029] Optionally, the three-dimensional filling path of the plurality of printing surfaces comprises a first printing path representation, and the first printing path representation comprises three-dimensional coordinates and normal vectors of a plurality of discrete path points in a printing substrate coordinate system.

[0030] The three-dimensional filling path of the plurality of printing curved surfaces is converted into a machine motion trajectory, comprising:

[0031] Obtaining a pose conversion relationship of a coordinate system of an end printing tool relative to a coordinate system of a base of a multi-axis robot arm, and a pose conversion relationship of a coordinate system of a printing substrate relative to the coordinate system of the base of the multi-axis robot arm;

[0032] According to the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the base of the multi-axis robot arm, the first printing path representation is converted into a second printing path representation in the coordinate system of the end printing tool;

[0033] According to the pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the base of the multi-axis robot arm, the second printing path representation is converted into a machine motion trajectory in the coordinate system of the base of the multi-axis robot arm.

[0034] Optionally, the conversion of the first printing path representation into the second printing path representation in the coordinate system of the end printing tool according to the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the base of the multi-axis robot arm comprises:

[0035] Taking an i-th discrete path point in the first printing path representation as an origin and taking a unitized normal vector as a Z-axis of the coordinate system of the end printing tool, a pose of the i-th discrete path point in the coordinate system of the end printing tool is constructed, and the second printing path representation comprises a pose of each discrete path point in the coordinate system of the end printing tool.

[0036] Optionally, the target material comprises fibers and resin, and the method further comprises:

[0037] Obtaining a cross-sectional parameter and a printing speed of a single-channel printing sample;

[0038] Determining a feeding rate of the fibers and a feeding rate of the resin according to the cross-sectional parameter and the printing speed;

[0039] The printing of the target material on the printing substrate by the multi-axis robot arm driving the end printing tool at the end of the multi-axis robot arm comprises:

[0040] Printing the target material on the printing substrate according to the feeding rate of the fibers and the feeding rate of the resin.

[0041] Optionally, the method further comprises: obtaining a fiber correction coefficient, and correcting the fiber feeding rate according to the fiber correction coefficient,

[0042] The printing target material on the printing base by the multi-axis robot arm with the end printing tool at the end of the multi-axis robot arm comprises: printing the fiber according to the modified fiber feeding rate;

[0043] and / or,

[0044] The method further comprises: obtaining a resin correction coefficient, and correcting the resin feeding rate according to the resin correction coefficient,

[0045] The printing target material on the printing base by the multi-axis robot arm with the end printing tool at the end of the multi-axis robot arm comprises: printing the resin according to the modified resin feeding rate.

[0046] Optionally, the modified fiber feeding rate is less than or equal to the unmodified fiber feeding rate, and the modified resin feeding rate is greater than or equal to the unmodified resin feeding rate.

[0047] Optionally, the obtaining of the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the robot base of the multi-axis robot arm and the pose conversion relationship of the coordinate system of the printing base relative to the coordinate system of the robot base further comprises:

[0048] Obtaining a first pose conversion relationship, the first pose conversion relationship being a pose conversion relationship of a coordinate system of an end printing tool relative to a coordinate system of a robot end, wherein the robot end is at the end of a robot fixed on a robot base, and is used to move the end printing tool so that the end printing tool prints material on a printing base;

[0049] Obtaining a second pose conversion relationship, the second pose conversion relationship being a pose conversion relationship of the coordinate system of the robot end relative to the coordinate system of the robot base;

[0050] According to the first pose conversion relationship and the second pose conversion relationship, obtaining a pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the robot base;

[0051] According to the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the robot base, obtaining a pose conversion relationship of the coordinate system of the printing base relative to the coordinate system of the robot base.

[0052] Optionally, the obtaining of the first pose conversion relationship comprises:

[0053] The end printing tool is sequentially contacted with the same reference point on the printing base at least twice by the robot arm with the end printing tool in different postures;

[0054] obtaining a pose transformation relationship of a coordinate system of the robot end effector relative to a coordinate system of the robot base at each time of the contact;

[0055] calculating a position vector of the coordinate system of the end printing tool relative to the coordinate system of the robot end effector according to the pose transformation relationship of the coordinate system of the robot end effector relative to the robot base in the at least two contacts.

[0056] Optionally, the obtaining the first pose comprises:

[0057] determining three feature points on the end printing tool, and a positional relationship between any two of the three feature points in the coordinate system of the end printing tool, the three feature points not being on the same straight line;

[0058] driving the end printing tool by the robot arm, so that the three feature points on the end printing tool are sequentially contacted with corresponding preset reference points on the printing substrate;

[0059] obtaining a pose transformation relationship of the robot end effector relative to the robot base when each of the feature points of the end printing tool is contacted with the corresponding reference point;

[0060] calculating a rotation matrix of the coordinate system of the end printing tool relative to the coordinate system of the robot end effector according to the positional relationship between any two of the three feature points in the coordinate system of the end printing tool, and the pose transformation relationship of the robot end effector relative to the robot base when each of the feature points of the end printing tool is contacted with the corresponding reference point.

[0061] Optionally, the obtaining the pose transformation relationship of the coordinate system of the printing substrate relative to the coordinate system of the robot base according to the pose of the coordinate system of the end printing tool relative to the coordinate system of the robot base comprises:

[0062] determining three feature points on the printing substrate, and a positional relationship between any two of the three feature points in the coordinate system of the printing substrate, the three feature points not being on the same straight line;

[0063] driving the end printing tool to be contacted with the three feature points respectively by the robot arm;

[0064] obtaining a pose transformation relationship of the robot end effector relative to the robot base when the end printing tool is contacted with each of the feature points respectively;

[0065] According to a positional relationship of any two feature points in the coordinate system of the printing substrate and a pose conversion relationship of the end of the mechanical arm relative to the base of the mechanical arm when the end printing tool contacts each of the feature points, a pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the base of the mechanical arm is determined.

[0066] In a third aspect, the present application provides a path planning device, comprising:

[0067] A first obtaining module is configured to obtain a structure parameter of a target structure.

[0068] A generating module is configured to generate a plurality of printing curved surfaces according to the structure parameter of the target structure, wherein the target structure comprises different first and second structures, and the plurality of printing curved surfaces comprise a first printing curved surface corresponding to the first structure and a second printing curved surface corresponding to the second structure.

[0069] A mapping module is configured to map the first and second printing curved surfaces to two-dimensional planes respectively by using different mapping functions, to obtain a first two-dimensional figure and a second two-dimensional figure.

[0070] A planning module is configured to plan a filling path in the first and second two-dimensional figures respectively, to obtain a first two-dimensional filling path and a second two-dimensional filling path.

[0071] The mapping module is further configured to map the first two-dimensional filling path back to the first printing curved surface, to obtain a three-dimensional filling path of the first printing curved surface.

[0072] The mapping module is further configured to map the second two-dimensional filling path back to the second printing curved surface, to obtain a three-dimensional filling path of the second printing curved surface.

[0073] In a fourth aspect, the present application provides an additive manufacturing device, comprising:

[0074] A second obtaining module is configured to obtain a three-dimensional filling path of a plurality of printing curved surfaces of a target structure.

[0075] A conversion module is configured to convert the three-dimensional filling paths of the plurality of printing curved surfaces into machine movement trajectories respectively.

[0076] A printing module is configured to print a target material on a printing substrate by using a multi-axis mechanical arm to drive an end printing tool located at an end of the multi-axis mechanical arm, according to the machine movement trajectories.

[0077] In a fifth aspect, the present application provides a path planning device, comprising a first memory and a first processor, wherein the first memory stores executable code, and when the executable code is processed by the first processor, the first processor can execute any of the path planning methods.

[0078] In a sixth aspect, the present application provides an additive manufacturing device, comprising a second memory and a second processor, wherein the second memory stores executable code, and when the executable code is processed by the second processor, the second processor can execute any of the additive manufacturing methods.

[0079] In a seventh aspect, the present application provides a computer readable storage medium, which stores executable code, and when the executable code is executed by a processor of an electronic device, the electronic device can execute any of the path planning methods or the additive manufacturing methods.

[0080] In the path planning method of the present application, the three-dimensional curved surface is mapped to a two-dimensional plane and then filled with a path planning, which reduces the calculation difficulty; and different mapping functions are used to map the printing curved surfaces of different structures in the target structure to a two-dimensional plane, which allows to explore different geometric designs (curved shell and reinforcing rib) and their filling paths at the same time, and can meet the filling needs of different structures. BRIEF DESCRIPTION OF DRAWINGS

[0081] Figure 1 is a schematic diagram of an embodiment of the path planning method of the present application;

[0082] Figure 2 is a comparative schematic diagram of the two-dimensional figures obtained by using equidistant mapping and using common mapping for the same curved surface;

[0083] Figure 3 is a comparative schematic diagram of the zigzag filling path on the two-dimensional plane and the three-dimensional curved surface associated by equidistant mapping;

[0084] Figure 4 is a comparative schematic diagram of the filling path based on arc offset on the two-dimensional plane and the three-dimensional curved surface associated by equidistant mapping;

[0085] Figure 5 is a comparative schematic diagram of the filling path based on contour offset on the two-dimensional plane and the three-dimensional curved surface associated by equidistant mapping;

[0086] Figure 6 is a comparative schematic diagram of the filling pattern based on ±30-degree cross lines on the two-dimensional plane and the three-dimensional curved surface associated by conformal mapping, respectively;

[0087] Figure 7are comparative schematic diagrams of a fill pattern based on ±45-degree cross lines on a two-dimensional plane and a three-dimensional curved surface respectively associated by a conformal mapping;

[0088] Figure 8 are comparative schematic diagrams of a fill pattern based on ±60-degree cross lines on a two-dimensional plane and a three-dimensional curved surface respectively associated by a conformal mapping;

[0089] Figure 9 are comparative schematic diagrams of a fill pattern based on elliptical cells on a two-dimensional plane and a three-dimensional curved surface respectively associated by a conformal mapping;

[0090] Figure 10 is a schematic diagram of one embodiment of the additive manufacturing method in the present application;

[0091] Figure 11 is a partial structural schematic diagram of one embodiment of the additive manufacturing apparatus in the present application;

[0092] Figure 12 is a schematic diagram of one embodiment of the conversion method for converting the three-dimensional fill paths of the plurality of printing curved surfaces into machine motion trajectories respectively in the additive manufacturing method in the present application;

[0093] Figure 13 is a schematic diagram of one embodiment of the calibration method of the additive manufacturing apparatus in the present application;

[0094] Figure 14 is a schematic diagram of one embodiment of the path planning device in the present application;

[0095] Figure 15 is a schematic diagram of one embodiment of the additive manufacturing device in the present application;

[0096] Figure 16 is a schematic diagram of one embodiment of the path planning device in the present application;

[0097] Figure 17 is a schematic diagram of one embodiment of the path planning device in the present application. DETAILED DESCRIPTION

[0098] Embodiments of the present application will be described in more detail by referring to the attached drawings. Although embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0099] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in this application and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0100] It should be understood that although the terms "first," "second," "third," etc. can be used in this application to describe various information, the information should not be limited to these terms. These terms are only used to distinguish one piece of information from another piece of information. For example, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information without departing from the scope of the application. Therefore, the features defined with "first," "second" can explicitly or implicitly include one or more of the features. Moreover, the objects referred to by the first and second in actual application can be the same object or different objects. In the description of the application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0101] The path planning method in the application can be used for path planning of continuous fiber reinforced lattice structures. The printing order of fiber paths has a significant impact on manufacturing efficiency and quality. However, existing continuous fiber path planning algorithms for lattice structures lack universality and can only plan paths for a specific shape of lattice structure. The path planning method proposed in the application can plan paths for lattice structures of different shapes, has a certain universality, and can ensure the continuity of the filling path and reduce the frequency of fiber cutting as much as possible, thereby improving the printing quality and manufacturing efficiency.

[0102] As shown in Figure 1 , FIG. 1 is a schematic diagram of an embodiment of the path planning method of the application. The path planning method comprises: Figure 1

[0103] In step S101, the structure parameters of the target structure are obtained.

[0104] ​The structure parameters of the target structure can be various parameters capable of representing the structural characteristics of the target structure, and the structure parameters of different types of structures can be the same or different. For example, the target structure is a reinforced shell structure, wherein the reinforced shell structure comprises a shell and reinforcing ribs on the surface of the shell. Optionally, the shell can be in the shape of a thin-walled shell, which is usually based on a developable surface; the reinforcing ribs distributed on the shell are usually based on a lattice structure layout composed of regular unit cells. The structure parameters of the reinforced shell structure can include a pre-labeled surface model and a structural normal thickness. For example, the structure parameters of the reinforced shell structure include a surface model, a normal thickness of the shell, a normal thickness of the reinforcing ribs, a single-layer thickness, and the like. The structure parameters of the reinforced shell structure can be input by a user or use default parameters.

[0105] Optionally, the surface model is a developable surface that can be unfolded onto a plane without any wrinkles or breaks. This can ensure the feasibility of unfolding the surface by isometric mapping in subsequent steps. Optionally, the developable surface is described by the following formula:

[0106]

[0107] wherein the curve is called a director, is a straight line vector called a generator, and u and v are orthogonal curvilinear coordinates in the parameter space.

[0108] In step S102, a plurality of printing surfaces are generated according to the structure parameters of the target structure.

[0109] The filling path in the present application is also used for layer-by-layer printing, but unlike conventional slicing software, the filling path on each layer in the present application is not a two-dimensional path in each two-dimensional slice obtained by conventional slicing software, but a three-dimensional path. The target structure comprises different first and second structures, and the plurality of printing surfaces comprise first printing surfaces corresponding to the first structure and second printing surfaces corresponding to the second structure.

[0110] ​​​​​​​​​Before obtaining the filling path on each layer of the target structure, a series of slice layers of the target structure, i.e., a series of printing surfaces, can be first constructed by offsetting the surface model in the structure parameters, wherein the series of printing surfaces are classified into different types of surfaces according to different positions, such as a plurality of printing surfaces corresponding to the first structure and a plurality of printing surfaces corresponding to the second structure. For aspect description, one of the plurality of printing surfaces corresponding to the first structure is referred to as a first printing surface, and one of the plurality of printing surfaces corresponding to the second structure is referred to as a second printing surface. Optionally, the surface model for constructing the plurality of printing surfaces of the first structure and the surface model for constructing the plurality of printing surfaces of the second structure can be the same surface model or different surface models.

[0111] Taking the reinforced shell structure as an example, before obtaining the filling path on each layer of the reinforced shell structure, a series of slice layers of the reinforced shell structure, i.e., a series of printing surfaces, can be first constructed by offsetting the surface model in the structure parameters, wherein the series of printing surfaces are classified into shell surface and reinforcing rib surface according to different positions. In one example, the shell surface is generated by offsetting the shell surface model along the normal direction by a distance H1, wherein H1 = single-layer thickness of the shell structure × number of layers. The reinforcing rib surface is generated by offsetting the reinforcing rib surface model along the normal direction by a distance H2, wherein H2 = single-layer thickness of the reinforcing rib structure × number of layers. Optionally, the normal offset vector of the shell surface model or the reinforcing rib surface model can be projected along the horizontal or vertical direction, and corrected by the correlation coefficient of the angle between the normal vector and the horizontal plane to ensure that the single-layer thickness along the normal direction remains unchanged to obtain high printing quality.

[0112] In step S103, different mapping functions are used to map the first printing surface and the second printing surface to a two-dimensional plane respectively to obtain a first two-dimensional graph and a second two-dimensional graph.

[0113] For each obtained printing surface, the printing surface is mapped to a two-dimensional plane to plan a filling path for the printing surface on the two-dimensional plane. Wherein the first printing surface and the second printing surface are respectively mapped to the two-dimensional plane by using different mapping functions to meet the filling requirements of different structures.

[0114] For example, in some cases, the first structure needs to use a full-fill method to plan the fill path. To maintain the length within the error range, the first printed surface can be mapped onto a two-dimensional plane using an equidistant mapping function, resulting in a first two-dimensional graphic. Although the first printed surface and the first two-dimensional graphic associated with the equidistant mapping have different shapes, they can be converted to each other through continuous deformation. That is, any corresponding curve on the first printed surface and the first two-dimensional graphic associated with the equidistant mapping has the same length. Therefore, without changing the single-track width, the full-fill pattern on the first two-dimensional graphic, after being mapped back to the first printed surface, still meets the full-fill requirement.

[0115] Optionally, the first printed surface is a developable surface, which ensures that the first printed surface has a corresponding isometric mapping function. Optionally, when the first printed surface is not a developable surface, or when a single developable surface cannot meet the error requirements, the first printed surface is converted into a combination of at least two developable surfaces, and the isometric mapping function is used to map the at least two developable surfaces onto a two-dimensional plane respectively to obtain a first two-dimensional graphic.

[0116] In some examples, when the fill path of the first structure is a regular shape, the first printed surface can be mapped to a two-dimensional plane using a conformal mapping function to obtain a second two-dimensional shape. Regular shapes are generally difficult to fit into complex polygons generated by isometric mapping. Therefore, using conformal mapping to map the second printed surface to a two-dimensional Euclidean plane is a relaxed representation of isometric mapping. The theoretical basis of conformal mapping is that, according to the single-valued theorem, any closed compact surface with a metric is isometrically embedded into one of three typical surfaces: a sphere, a plane, or hyperbolic space through its single-valued conformal metric. Furthermore, conformal mapping is conformal, hence it is also called conformal mapping.

[0117] like Figure 2 As shown, Figure 2 This diagram illustrates the comparison between the two-dimensional graphics obtained by applying isometric mapping and conformal mapping to the same surface. Surface 21 is mapped into an arc-shaped strip 22 through the isometric mapping function, and into a rectangular strip 23 through the conformal mapping function. The grids in surface 21, arc-shaped strip 22, and rectangular strip 23 are all orthogonal lines, used to illustrate the surface relationship before and after mapping. In the isometric mapping, any corresponding lines on surface 21 and arc-shaped strip 22 have the same length; in the conformal mapping, any two curves on surface 21 and rectangular strip 23 have the same included angle.

[0118] In the example where the target structure is a stiffened shell structure, for each shell surface and each stiffener surface, the shell surface and the stiffener surface are respectively mapped to a two-dimensional plane to plan the filling path on the two-dimensional plane for the shell surface and the stiffener surface respectively. Optionally, the shell surface is mapped to the two-dimensional plane using an equi-rectangular mapping function, while the stiffener surface is mapped to the two-dimensional plane using a conformal mapping function. For the stiffener surface, since the stiffeners distributed on the shell are usually based on a grid layout, which is typically characterized by a number of regular cells arranged in a rectangular form. Using the conformal mapping function can preserve the local shape at any position on the stiffener surface. This helps to preserve the physical properties of the structure, such as the stiffener angle, which has a significant impact on the mechanical performance of the structure.

[0119] At step S104, filling paths are planned in the first two-dimensional graph and the second two-dimensional graph respectively to obtain a first two-dimensional filling path and a second two-dimensional filling path.

[0120] The filling patterns, i.e. filling paths, can be generated in the first two-dimensional graph and the second two-dimensional graph respectively using a filling pattern generation algorithm for a planar layer printing process. For example, a line scan, a contour offset, a Fermat spiral, etc. algorithm can be used to generate the filling patterns according to the requirements.

[0121] Specifically, various filling patterns such as a herringbone pattern, a contour offset pattern and a honeycomb structure can be generated in the first two-dimensional graph (e.g. the shell two-dimensional graph in the stiffened shell structure). As shown in Figures 3-5 Figure 3 is a comparison diagram of a zigzag filling path on a two-dimensional plane associated with equi-rectangular mapping and a three-dimensional surface. Figure 4 is a comparison diagram of an arc offset-based filling path on a two-dimensional plane associated with equi-rectangular mapping and a three-dimensional surface. Figure 5 is a comparison diagram of a contour offset-based filling path on a two-dimensional plane associated with equi-rectangular mapping and a three-dimensional surface. As can be seen, the zigzag filling path, the arc offset-based filling path and the contour offset-based filling path can meet the complete filling requirement of the first two-dimensional graph. Wherein any corresponding curve on the first printing surface associated with equi-rectangular mapping and the first two-dimensional graph has the same length. For example, Figure 3 the length of the zigzag filling path in is 158.03 mm on the first printing surface associated with equi-rectangular mapping and the first two-dimensional graph, Figure 4 the length of the arc offset-based filling path in is 81.85 mm on the first printing surface associated with equi-rectangular mapping and the first two-dimensional graph, Figure 5 the length of the contour offset-based filling path in is 312.39 mm on the first printing surface associated with equi-rectangular mapping and the first two-dimensional graph.

[0122] ​In this process, some filling parameters, such as single-track width and fiber filling angle of zigzag pattern, can be adjusted within a certain range to achieve diversified filling pattern generation.

[0123] The second two-dimensional pattern (e.g., the reinforcing rib two-dimensional pattern in the reinforced shell structure) generated by the conformal mapping is a regular rectangle, so the periodically arranged unit cells can be quickly filled into the reinforcing rib two-dimensional pattern to generate reinforcing ribs distributed on the shell, and the periodically arranged unit cells also represent three-dimensional filling paths. As shown in FIGS. 6-8, Figure 6 are contrastive schematic diagrams of filling patterns based on ±30-degree intersecting lines on the two-dimensional plane and the three-dimensional curved surface associated with the conformal mapping, respectively, Figure 7 are contrastive schematic diagrams of filling patterns based on ±45-degree intersecting lines on the two-dimensional plane and the three-dimensional curved surface associated with the conformal mapping, respectively, Figure 8 are contrastive schematic diagrams of filling patterns based on ±60-degree intersecting lines on the two-dimensional plane and the three-dimensional curved surface associated with the conformal mapping, respectively. As can be seen, any corresponding curve on the first printing curved surface and the first two-dimensional pattern associated with the conformal mapping has the same included angle. The filling pattern is formed by straight lines of different angles that are uniformly distributed along the parameter axes (u and v) and intersect with each other. In this process, the angles and the number of straight lines can be adjusted to produce a variety of grid structures.

[0124] In addition, more complex grid structures can also be generated by periodically filling a variety of basic cells, for example, as shown in Figure 9 are contrastive schematic diagrams of filling patterns based on elliptical cells on the two-dimensional plane and the three-dimensional curved surface associated with the conformal mapping, respectively. The periodically arranged basic cells filled on the two-dimensional plane are still periodically arranged basic cells on the three-dimensional curved surface. Since the conformal mapping only preserves angles and does not preserve lengths, the three-dimensional pattern obtained by mapping after uniform filling on the two-dimensional curved surface will be stretched or shrunk, and therefore, the size of each two-dimensional filling unit cell on the two-dimensional plane can be optionally adjusted according to the shrinkage rate at each point to obtain a three-dimensional pattern with uniformly sized unit cells.

[0125] Step S105, mapping the first two-dimensional filling path back to the first printing curved surface to obtain a three-dimensional filling path of the first printing curved surface.

[0126] Step S106, mapping the second two-dimensional filling path back to the second printing curved surface to obtain a three-dimensional filling path of the second printing curved surface.

[0127] According to the computational conformal geometry theory, the mapping function f is homeomorphic, i.e. the mapping function and its inverse mapping are one-to-one. Therefore, the first two-dimensional filling path and the second two-dimensional filling path can be mapped back to the three-dimensional printing surface through the inverse mapping relationship. Finally, all the three-dimensional filling paths generated in the first printing surface and the second printing surface are combined and stored in the form of a series of ordered discrete point sets. Optionally, the surface normal vector corresponding to each discrete point is also calculated for robot trajectory generation in the machine code conversion.

[0128] In the path planning method in the present application, the three-dimensional surface is mapped to a two-dimensional plane before filling path planning, which reduces the computational difficulty. Moreover, different mapping functions are used to map the printing surfaces of different structures in the target structure to a two-dimensional plane, allowing the exploration of different geometric designs (curved shell and reinforcing rib) and their filling paths at the same time, which can meet the filling needs of different structures. For example, in the example of reinforced shell structure, the complete filling needs of the shell structure and the needs of using regular cellular conformal filling complex curved surface for reinforcing rib structure can be met at the same time. In addition, it can also allow a variety of filling path types under the condition of ensuring uniform and uniform width, which can be combined with the significant mechanical anisotropy of fiber reinforced composites, which makes the shape-preserving CFRP-AM process have stronger performance adjustment ability.

[0129] Optionally, the path planning method in the present application can be used for additive manufacturing. The following will be described in combination with Figure 10 An embodiment of the additive manufacturing method in the present application is described by way of example. As shown in Figure 10 , Figure 10 is a schematic diagram of an embodiment of the additive manufacturing method in the present application. The additive manufacturing method comprises:

[0130] Step S1001, obtaining three-dimensional filling paths of a plurality of printing surfaces of a target structure.

[0131] The method for obtaining the three-dimensional filling paths of the plurality of printing surfaces of the target structure can refer to the path planning method described above, which will not be described here.

[0132] Step S1002, converting the three-dimensional filling paths of the plurality of printing surfaces into machine motion trajectories respectively.

[0133] Different additive manufacturing equipment may require different machine motion trajectories. The structure of the additive manufacturing equipment can be various. In one example, as shown in Figure 11 , Figure 11Figure 1 is a schematic diagram of a part of a structure of an embodiment of the additive manufacturing apparatus of the present application. In this embodiment, the additive manufacturing apparatus 10 comprises a robot base 11, a robot 12 fixed on the robot base 11, and an end printing tool 13 disposed at the end of the robot 12. Optionally, the additive manufacturing apparatus further comprises a removable printing substrate 14 within the working space of the robot 12. The robot 12 is configured to drive the end printing tool 13 to print material on the printing substrate 14. During the printing process, the end printing tool disposed at the end of the multi-axis robot is driven by the multi-axis robot to print on a plurality of sliced layers one by one. Generally, the three-dimensional filling path of the plurality of printing curves is represented in the coordinate system of the printing substrate, and therefore the three-dimensional filling path of the plurality of printing curves needs to be converted into the machine motion trajectory in the coordinate system of the robot base.

[0134] In one example, the three-dimensional filling path of the plurality of printing curves comprises a first printing path representation, and the first printing path representation comprises three-dimensional coordinates and normal vectors of a plurality of discrete path points in the coordinate system of the printing substrate.

[0135] At step S1003, the end printing tool disposed at the end of the multi-axis robot is driven by the multi-axis robot to print the target material according to the machine motion trajectory.

[0136] Optionally, the target material can be a composite material, a resin material, a liquid metal, etc. For example, the target material is a continuous fiber reinforced composite material. The end printing tool disposed at the end of the multi-axis robot can be an end printing tool of a five-axis motion platform or a six-axis robot motion platform, or an eight-degree-of-freedom end printing tool with a six-axis robot plus a two-axis rotation platform, or a twelve-axis end printing tool with a double six-axis robot cooperation. Using multi-degree-of-freedom motion to directly manufacture non-planar features of a structure can greatly expand the design freedom of fiber laying, so that the fiber can enhance the mechanical properties of the component in any desired direction, greatly improving the performance of the component. Optionally, the end printing tool can be part of a CFRP-AM manufacturing system or other manufacturing system, which is not limited herein.

[0137] In step S1002, the three-dimensional filling path of the plurality of printing curves is converted into the machine motion trajectory in various ways. The following examples are described with reference to the embodiment shown in Figure 1. Figure 12 For Figure 10 example, the three-dimensional filling path of the plurality of printing curves is converted into the machine motion trajectory in the coordinate system of the robot base by using a B-Rep method.

[0138] For example, the three-dimensional filling path of the plurality of printing curves is converted into the machine motion trajectory in the coordinate system of the robot base by using a B-Rep method. Figure 12 Figure 12 ​is a schematic diagram of an embodiment of a conversion method in the additive manufacturing method in the present application for converting the three-dimensional filling paths of the plurality of printing surfaces into machine motion trajectories respectively. The conversion method comprises:

[0139] In step S1201, a pose conversion relationship of a coordinate system of an end printing tool relative to a coordinate system of a robot base, and a pose conversion relationship of a coordinate system of a printing substrate relative to the coordinate system of the robot base are obtained.

[0140] The pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the robot base, and the pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the robot base can be calibrated in advance by a calibration method and stored, and the two pose conversion relationships can be obtained by reading the calibration data stored. Alternatively, the two pose conversion relationships can be obtained by real-time calibration.

[0141] Therefore, the generated three-dimensional filling paths of the plurality of printing surfaces can be converted into the coordinate system of the robot base for unified description.

[0142] In step S1202, the first printing path representation is converted into a second printing path representation in the coordinate system of the end printing tool according to the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the robot base.

[0143] In order to guide the movement of the robot, the generated first printing path representation needs to be converted into a series of ordered poses in the coordinate system of the end printing tool, i.e. the position and orientation of the end printing tool. At the same time, since in the printing process, the Zi axis of the end printing tool when printing the ith discrete point is forced to align with the normal vector of the discrete path point. Therefore, the trajectory generation process of the robot is to construct a series of pose descriptions of the coordinate system of the end printing tool relative to the coordinate system of the robot base, taking the discrete point as the origin and the unitized normal vector as the Zi axis. As for the Xi and Yi axes of the coordinate system of the end printing tool when printing the ith discrete point, any two orthogonal vectors on the normal of the Zi axis can be selected. This is because the nozzle tip is circular, and the rotation around the Z axis has little effect on the deposition of any single track.

[0144] In step S1203, the second printing path representation is converted into a machine motion trajectory in the coordinate system of the robot base according to the pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the robot base.

[0145] Optionally, the X-axis vector of the coordinate system of the printing substrate is unitized in the projection vector on the plane corresponding to the Z-axis vector of the coordinate system of the end printing tool, for creating the Xi-axis vector of the coordinate system of the end printing tool. The Yi-axis vector is calculated by the cross product of the Zi and Xi-axis vectors. Thus, the transformation matrix of the coordinate system of the end printing tool relative to the coordinate system of the printing substrate is constructed by the three calculated axis vectors and the discrete point coordinates, which is abbreviated as:

[0146]

[0147] where i represents the data of the ith discrete path point. Then, the constructed pose of the end printing tool is further converted into the robot base coordinate system for representation, and the transformation matrix is as follows:

[0148]

[0149] where B represents the robot base, T represents the end printing tool, and S represents the printing substrate.

[0150] Step S1204, according to the machine motion trajectory, the end printing tool is driven by the multi-axis robot arm to print the target material.

[0151] Optionally, the additive manufacturing device further converts the three-dimensional printing path converted into the coordinate system of the robot base into a machine recognizable code. The machine recognizable code can include the robot trajectory and the printing material feeding rate. Optionally, some key design parameters that have a significant impact on the printing quality are adjustable, such as layer thickness, single pass width, filling path pattern, printing speed, etc. Finally, after being converted into the machine recognizable code, the machine recognizable code is distributed to the coordinate systems of the robot arm and the end printing tool as needed, and high-quality printing is achieved through the good cooperation of the two modules.

[0152] The machine motion trajectory is generated machine code, which is parsed and distributed to the corresponding module controller at a certain time interval. Optionally, during the operation of the additive manufacturing equipment, the set temperature data is first sent to the co-extrusion controller through serial communication, and the built-in PID control program controls the heating rod on-off frequency to control the nozzle to heat to the specified temperature. Then, the control instruction corresponding to the motion of the mechanical arm is sent to the mechanical arm controller through Ethernet and the end motion speed of the mechanical arm is output to the host computer at a certain time interval for calculating the composite material feeding rate. The calculated composite material feeding rate is sent to the co-extrusion end through serial communication to update the motor speed in real time to realize the mutual matching of the printing speed and the material feeding rate. After each sub-path is printed, the mechanical arm and the material feeding module stop moving, the host computer sends a fiber cutting command to drive the servo motor to cut off the fiber. When all the paths are printed, the host computer sends a termination command to stop the nozzle heating and move the mechanical arm to a safe position, and then the user takes out the printed part.

[0153] In one example, the mechanical arm employs a UR10e robot, and the transformation matrix usually needs to be expressed in the rotation amount method, i.e., a more concise vector form where [x, y, z] is the coordinate of the discrete point, The rotation vector is represented. In addition, based on the motion control mode of the joint vector , the given TCF pose needs to be converted into 6 joint angles through inverse kinematics. The inverse kinematics problem can be solved by the robot kinematic chain model, i.e., D-H parameters, by using an analytical method or a numerical iterative method.

[0154] In order to produce high-quality parts, the extrusion rate of the material needs to be precisely synchronized with the motion of the mechanical arm. More specifically, the mutual matching relationship between the robot kinematics and the deposition process parameters along the CFRP-AM printing path needs to be modeled and precisely controlled.

[0155] Optionally, the target material includes fibers and resin; in the additive manufacturing method of the present application, the cross-sectional parameters and the printing speed of the single-path printed sample are also obtained; the fiber feeding rate and the resin feeding rate are determined according to the cross-sectional parameters and the printing speed. For example, the cross section of the single-path printed sample can be observed by a scanning electron microscope (SEM). The cross section of the manufactured single-path sample can be represented as a rounded rectangle with a semi-wrapped fiber bundle. Alternatively, the single-layer thickness (h) and the single-path width (w) can be used to describe the cross-sectional morphology.

[0156] The parameters E1 and E2 represent the feeding rate of the fiber and resin wire, i.e. the length of the wire fed into the print head per unit time. At a given printing speed (v), E1 has a great influence on the collimation and pre-stress of the deposited fibers, thereby affecting the overall mechanical properties of the printed part. Therefore, optionally, in the additive manufacturing method of the present application, a fiber correction coefficient is also obtained, the fiber feeding rate is corrected according to the fiber correction coefficient, and the fiber is printed according to the modified fiber feeding rate. Optionally, the fiber correction coefficient is less than or equal to 1, so that the modified fiber feeding rate is less than or equal to the fiber feeding rate before correction. In one example, the fiber correction coefficient is set to 0.95 - 1.0.

[0157] Optionally, a resin correction coefficient is also obtained, the resin feeding rate is corrected according to the resin correction coefficient, and the resin is printed according to the modified resin feeding rate. Optionally, the resin correction coefficient is greater than or equal to 1, so that the modified resin feeding rate is greater than or equal to the resin feeding rate before correction. This is because in the deposition model of multiple layers and multiple passes, it can be found that there are gap areas in the printed part. In this study, k2 is usually set to 1.0 - 1.15 to reduce voids. Less voids tend to help improve mechanical properties, but excessive parameter settings can cause excessive resin accumulation, which is not conducive to the surface quality of the part.

[0158] According to the principle of volume conservation, the quantitative relationship between the feeding rate of the composite material and the printing speed is expressed as follows:

[0159]

[0160] where the printing speed v, the single layer thickness h, the single bead width w, the resin wire diameter and the correction coefficients k1 and k2 can be set by the user or set by default. In addition, the feeding rate of the material needs to be converted into the control pulse frequency to control the motor rotation rate.

[0161] In one specific example, the additive manufacturing device comprises four main modules: a control host, a six-axis robot motion module, a fiber-resin co-extrusion printing end, and a replaceable pre-made freeform substrate. The control host is mainly used for pre-processing process planning and motion control, specifically to first output a machine execution file through a process planning algorithm, and then send corresponding motion control instructions to the controllers of the robot arm and the co-extrusion end respectively, to realize the cooperation of the two and complete the manufacturing of the composite structure. The six-axis robot motion module is used to realize the multi-degree-of-freedom motion of the system, and its high motion flexibility has a significant advantage in avoiding collisions and singular points, which can be used to improve the smoothness of the printing path. Optionally, the six-axis robot arm is installed on an optical vibration isolation platform, with a spherical workspace radius of 1300 mm centered on the base of the robot arm, and an effective working load of 10 kg at the end. In addition, the repeatability of the robot arm is ±0.05 mm, and the maximum speed of the center point of the end printing tool is 1000 mm / s. The fiber-resin co-extrusion printing module is fixed to the coordinate system at the end of the robot arm, including a fiber feeding device, a resin extruder, a fiber shearing device, a co-extrusion nozzle, and a temperature control device. This printing end is designed and developed internally, especially based on the results of heat-flow field coupling simulation to optimize the internal flow channel of the co-extrusion nozzle to improve the impregnation effect of the fiber inside the melting chamber. The nozzle outlet diameter is 1 mm and is rounded to achieve ironing and extrusion after material extrusion and to avoid fiber cutting. The maximum heating temperature of the nozzle is 300°C, which can meet the application requirements of most thermoplastic engineering plastics. The freeform substrate is used to provide an attachment basis for the first layer of composite material to ensure high printing quality. At the same time, it cannot be installed too close to the edge of the robot arm workspace, as this will increase the likelihood of the robot arm reaching the joint limit. In addition, the substrate can be manufactured using various processes and reused.

[0162] In some examples, the gap between the tip of the end printing tool and the previous slice layer is an important factor affecting the printing quality. Therefore, the position and orientation of the end printing tool and the printing substrate in the robot base coordinate system are accurately calibrated to ensure that the gap is accurate and uniform on each printed slice layer.

[0163] Optionally, the calibration method is used to calibrate the position and orientation of the coordinate system of the end printing tool and the coordinate system of the printing substrate relative to the robot base coordinate system, respectively, to ensure good printing quality. Specifically, as Figure 11As shown, the calibration process is to establish the mathematical description of the pose relationship of the center coordinate system of the coordinate system of the printing substrate (Substrate Frame, SF) and the coordinate system of the end printing tool (Tool Center Frame, TCF) relative to the coordinate system of the base of the mechanical arm (Base Frame, BF). In the calibration method of the application, in addition to the three coordinate systems, the coordinate system of the end of the mechanical arm (End Frame, EF) is introduced to assist in calibration.

[0164] Optionally, the mechanical arm is a six-axis mechanical arm. Optionally, the coordinate system of the end printing tool is used to print continuous fiber reinforced composites on the coordinate system of the printing substrate. Optionally, the coordinate system of the end printing tool is a fiber-resin co-extrusion printing nozzle. Optionally, the coordinate system of the printing substrate is replaceable. Optionally, the coordinate system of the printing substrate is a prefabricated free-form substrate. The following will be described in detail in combination with Figure 11 and Figure 13 A calibration method for the additive manufacturing device in the application is exemplified. As shown in Figure 13 , Figure 13 is a schematic diagram of an embodiment of the calibration method of the additive manufacturing device of the application. The calibration method comprises:

[0165] Step S1301, obtaining a first pose conversion relationship, the first pose being the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the end of the mechanical arm.

[0166] The pose of the coordinate system of the end printing tool relative to the coordinate system of the end of the mechanical arm represents the position and orientation of TCF relative to EF. In the mathematical model, this pose conversion relationship is usually represented by a conversion matrix, that is:

[0167]

[0168] Where R is a rotation matrix and P is a translation vector. Denote the coordinate system of the end of the mechanical arm as E and the coordinate system of the end printing tool as T, then the conversion matrix describes the pose of the coordinate system of the end printing tool relative to the coordinate system of the end of the mechanical arm, which includes the rotation matrix and the position vector .

[0169] In one example, the end of the robot arm can be moved by the robot arm, and in turn the end printing tool can be moved by the end of the robot arm, to sequentially contact the same reference point on the printing substrate in different poses, to obtain the pose transformation relationship of the coordinate system of the end of the robot arm relative to the coordinate system of the base of the robot arm at each contact, and to calculate the position vector of the coordinate system of the end printing tool relative to the coordinate system of the end of the robot arm according to the pose transformation relationship of the coordinate system of the end of the robot arm relative to the base of the robot arm at the at least two contacts.

[0170] For example, a conical reference object can be fixed at a suitable position in the workspace of the robot arm, with the tip of the conical reference object as the reference point. Optionally, the position of the conical reference object is away from the edge of the workspace of the robot arm. Then, the robot arm is controlled to move the end printing tool so that the center of the end printing tool (e.g. the center of the end nozzle) contacts the tip of the conical reference object multiple times, e.g. at least 4 times, in different poses. At the ith contact in the multiple contacts, the rotation matrix and the position vector are obtained, where B denotes the coordinate system of the base of the robot arm, and it can be understood that and satisfy:

[0171] (1)

[0172] Since the tip of the conical reference object is fixed and the base of the robot arm is fixed during the contact, the rotation matrix remains unchanged at each contact, and the position vector of the coordinate system of the end printing tool relative to the coordinate system of the end of the robot arm remains unchanged. Therefore, by subtracting the above equation (1) obtained at any two contacts and then combining these equations, a linear equation system is obtained. For this equation system, by using the linear least squares method, the best fitting of the position vector of the coordinate system of the end printing tool relative to the coordinate system of the end of the robot arm can be obtained, i.e.

[0173]

[0174] The rotation matrix of the coordinate system of the end printing tool relative to the coordinate system of the end of the robot arm can be directly obtained from the mechanical design model. Alternatively, another more accurate method is to set feature points related to the coordinate system on the coordinate system of the end printing tool, and use the known mutual position relationship of these feature points to obtain the rotation matrix of the coordinate system of the end printing tool relative to the coordinate system of the end of the robot arm .

[0175] Specifically, three feature points are determined on the end printing tool, and a positional relationship between any two of the three feature points in a coordinate system of the end printing tool, the three feature points are not on the same straight line; the end printing tool is driven by the mechanical arm, so that the three feature points on the end printing tool are in turn in contact with the corresponding preset reference points on the printing substrate; the pose transformation relationship of the mechanical arm end relative to the mechanical arm base when each feature point of the end printing tool is in contact with the corresponding preset reference point is obtained respectively; according to the positional relationship between any two of the three feature points in the coordinate system of the end printing tool, and the pose transformation relationship of the mechanical arm end relative to the mechanical arm base when each feature point of the end printing tool is in contact with the corresponding preset reference point, the rotation matrix of the coordinate system of the end printing tool relative to the coordinate system of the mechanical arm end is calculated. Wherein, the corresponding preset reference points of the three feature points can be the same preset reference point, or different preset reference points.

[0176] Wherein, the three feature points determined on the end printing tool can be the origin in the coordinate system of the end printing tool, any point on one of the axes, and any point on the plane of the axis. For example, the three feature points determined on the end printing tool can be the origin in the coordinate system of the end printing tool, a point on the X-axis or Y-axis, and a point on the XY plane.

[0177] Step S1302, a second pose transformation relationship is obtained, the second pose being a pose transformation relationship of a coordinate system of the mechanical arm end relative to a coordinate system of the mechanical arm base.

[0178] Optionally, the mechanical arm base is denoted as B, the mechanical arm end is denoted as E, the transformation matrix The pose of the coordinate system of the mechanical arm end relative to the target mechanical arm is described, including a rotation matrix And a position vector The transformation matrix Can be calculated by a forward kinematics model built in the mechanical arm controller.

[0179] Step S1303, according to the first pose transformation relationship and the second pose transformation relationship, a pose transformation relationship of the coordinate system of the end printing tool relative to the coordinate system of the mechanical arm base is determined.

[0180] The transformation matrix of the coordinate system of the end printing tool relative to the coordinate system of the mechanical arm base Can be represented as

[0181] = * =

[0182] wherein the transformation matrix The pose of the coordinate system of the end of the robot arm relative to the coordinate system of the robot arm base is described, which contains a rotation matrix and a position vector .

[0183] Step S1304, according to the pose of the coordinate system of the end of the printing tool relative to the coordinate system of the robot arm base, determine the pose transformation relationship of the coordinate system of the printing substrate relative to the coordinate system of the robot arm base.

[0184] Specifically, three feature point positions are designed on the coordinate system of the printing substrate for auxiliary calibration. For example, the three feature point positions are the origin point P0 in the coordinate system of the printing substrate, the offset point P1 on the X axis, and the arbitrary point P2 on the XY plane. The position vectors of these feature point positions relative to the coordinate system of the robot arm base are measured by moving the robot arm to make the center point of the end of the printing tool (such as the center point of the co-extrusion nozzle) contact, and then the known position relationship between each feature point position is combined to quickly construct the transformation matrix of the coordinate system of the end of the printing tool relative to the coordinate system of the printing substrate.

[0185] In one example, the position vector of the feature point position P0 to P1 is unitized, which is the X axis vector. The Y axis vector needs to be calculated first, and then the position vector of the P0 point to the P2 point is calculated, and then the vector is unitized. The projection vector of the X axis vector on the normal plane. Finally, the Z axis vector can be calculated by the vector product of the X axis vector and the Y axis vector. Therefore, the constructed transformation matrix is:

[0186]

[0187] wherein X, Y, Z are respectively the X axis, Y axis, Z axis vectors described in the coordinate system of the robot arm base, and P0 is the origin coordinate of the coordinate system of the printing substrate relative to the coordinate system of the robot arm base. Optionally, the robot arm can be controlled to drive the end of the printing tool to measure multiple times at each feature point position to reduce errors.

[0188] In the embodiments of the present application, by obtaining the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the end of the mechanical arm, and the pose conversion relationship of the coordinate system of the end of the mechanical arm relative to the coordinate system of the base of the mechanical arm, the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the base of the mechanical arm, and the pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the base of the mechanical arm can be calibrated, which facilitates subsequent conversion of the planned printing path to the base coordinate system of the mechanical arm after the printing path is obtained, so as to ensure good printing quality.

[0189] The pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the base of the mechanical arm, and the pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the base of the mechanical arm can be stored for repeated use, and the calibration method of the present application can be performed when a certain module in the additive manufacturing device is replaced or repaired. Alternatively, the calibration method of the present application can also be performed before each printing task, which is not limited herein.

[0190] The present application also provides a path planning device, as shown in Figure 14 Figure 14 is a schematic diagram of an embodiment of the path planning device 1400 of the present application, which comprises:

[0191] The first acquisition module 1401 is configured to acquire the structure parameters of the target structure.

[0192] The generation module 1402 is configured to generate a plurality of printing curved surfaces according to the structure parameters of the target structure, wherein the target structure comprises different first structures and second structures, and the plurality of printing curved surfaces comprise first printing curved surfaces corresponding to the first structures and second printing curved surfaces corresponding to the second structures.

[0193] The mapping module 1403 is configured to map the first printing curved surfaces and the second printing curved surfaces to two-dimensional planes respectively by using different mapping functions, to obtain first two-dimensional graphics and second two-dimensional graphics.

[0194] The planning module 1404 is configured to plan filling paths in the first two-dimensional graphics and the second two-dimensional graphics respectively, to obtain first two-dimensional filling paths and second two-dimensional filling paths.

[0195] The mapping module 1403 is further configured to map the first two-dimensional filling paths back to the first printing curved surfaces, to obtain three-dimensional filling paths of the first printing curved surfaces.

[0196] The mapping module 1403 is further configured to map the second two-dimensional filling paths back to the second printing curved surfaces, to obtain three-dimensional filling paths of the second printing curved surfaces. ​

[0197] Optionally, the planning module 1404 is specifically configured to plan the filling path in the first two-dimensional graph in a full-filling manner, to obtain a first two-dimensional filling path.

[0198] Optionally, the mapping module 1403 is specifically configured to:

[0199] When the first printing curved surface is a developable curved surface, the first printing curved surface is mapped onto a two-dimensional plane by using an equidistant mapping function, to obtain a first two-dimensional graph; or,

[0200] When the first printing curved surface is not a developable curved surface, the first printing curved surface is converted into a combination of at least two developable curved surfaces, and the at least two developable curved surfaces are respectively mapped onto a two-dimensional plane by using an equidistant mapping function, to obtain a first two-dimensional graph.

[0201] Optionally, the mapping module 1403 is specifically configured to map the second printing curved surface onto a two-dimensional plane by using a conformal mapping function, to obtain a second two-dimensional graph.

[0202] The planning module 1404 is specifically configured to plan a filling path in the second two-dimensional graph, to obtain a second filling path with a regular graph.

[0203] Optionally, the target structure is a reinforced shell structure, the reinforced shell structure includes a shell and a reinforcing rib located on the surface of the shell; the first structure is the shell, and the second structure is the reinforcing rib.

[0204] The present application also provides an additive manufacturing device, such as Figure 15 as shown in the accompanying drawings, Figure 15 is a schematic diagram of an embodiment of the additive manufacturing device of the present application, the path planning device 1500 includes:

[0205] A second acquisition module 1501 is configured to acquire a three-dimensional filling path of a plurality of printing curved surfaces of a target structure.

[0206] A conversion module 1502 is configured to convert the three-dimensional filling path of the plurality of printing curved surfaces into a machine motion trajectory, respectively.

[0207] A printing module 1503 is configured to print a target material on a printing base by using a multi-axis mechanical arm to drive an end printing tool located at the end of the multi-axis mechanical arm according to the machine motion trajectory.

[0208] Optionally, the three-dimensional filling path of the plurality of printing curved surfaces includes a first printing path representation, and the first printing path representation includes three-dimensional coordinates and normal vectors of a plurality of discrete path points in a printing base coordinate system.

[0209] The conversion module 1502 is specifically configured to:

[0210] obtain a pose conversion relationship of a coordinate system of an end printing tool relative to a coordinate system of a robot base of the multi-axis robot arm, and a pose conversion relationship of a coordinate system of a printing substrate relative to the coordinate system of the robot base;

[0211] convert the first printing path representation into a second printing path representation in the coordinate system of the end printing tool according to the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the robot base;

[0212] convert the second printing path representation into a machine motion trajectory in the coordinate system of the robot base according to the pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the robot base.

[0213] Optionally, the conversion of the first printing path representation into the second printing path representation in the coordinate system of the end printing tool according to the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the robot base comprises:

[0214] constructing a pose of the i-th discrete path point in the coordinate system of the end printing tool with the i-th discrete path point in the first printing path representation as the origin and the unitized normal vector as the Z-axis of the coordinate system of the end printing tool, the second printing path representation comprising the pose of each discrete path point in the coordinate system of the end printing tool.

[0215] Optionally, the target material comprises fibers and resin, and the additive manufacturing device further comprises:

[0216] a third obtaining module configured to obtain a cross-section parameter and a printing speed of a single-pass printing sample;

[0217] a determining module configured to determine a feeding rate of the fibers and a feeding rate of the resin according to the cross-section parameter and the printing speed;

[0218] The printing module is specifically configured to:

[0219] print the target material on the printing substrate according to the feeding rate of the fibers and the feeding rate of the resin.

[0220] Optionally, the additive manufacturing device further comprises:

[0221] The fourth obtaining module is configured to obtain a fiber correction coefficient; and the first correction module is configured to correct the fiber feed rate according to the fiber correction coefficient; the printing module 1503 is specifically configured to print the fiber according to the corrected fiber feed rate; and / or,

[0222] The fifth obtaining module is configured to obtain a resin correction coefficient; and the second correction module is configured to correct the resin feed rate according to the resin correction coefficient; and the printing module 1503 is specifically configured to print the resin according to the corrected resin feed rate.

[0223] Optionally, the corrected fiber feed rate is less than or equal to the fiber feed rate before correction, and the corrected resin feed rate is greater than or equal to the resin feed rate before correction.

[0224] Optionally, the additive manufacturing device further comprises a calibration module configured to, before obtaining a pose conversion relationship of a coordinate system of an end printing tool relative to a coordinate system of a base of a multi-axis robot arm and a pose conversion relationship of a coordinate system of a printing substrate relative to the coordinate system of the base of the robot arm:

[0225] obtain a first pose conversion relationship, the first pose conversion relationship being a pose conversion relationship of a coordinate system of an end printing tool relative to a coordinate system of an end of a robot arm, wherein the end of the robot arm is located at an end of a robot arm fixed on a base of the robot arm, and is configured to move the end printing tool so that the end printing tool prints a material on a printing substrate;

[0226] obtain a second pose conversion relationship, the second pose conversion relationship being a pose conversion relationship of the coordinate system of the end of the robot arm relative to the coordinate system of the base of the robot arm;

[0227] determine, according to the first pose conversion relationship and the second pose conversion relationship, a pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the base of the robot arm;

[0228] determine, according to the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the base of the robot arm, a pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the base of the robot arm.

[0229] Optionally, the first pose conversion relationship is obtained by:

[0230] the end printing tool is sequentially contacted with a same reference point located on the printing substrate in different postures by the robot arm at least twice;

[0231] acquire a pose transformation relationship of a coordinate system of the robot end effector relative to a coordinate system of the robot base at each time of the contact;

[0232] calculate a position vector of the coordinate system of the end printing tool relative to the coordinate system of the robot end effector according to the pose transformation relationship of the coordinate system of the robot end effector relative to the robot base in the at least two contacts.

[0233] Optionally, the acquiring the first pose comprises:

[0234] determine three feature points on the end printing tool, and a positional relationship of any two feature points of the three feature points in the coordinate system of the end printing tool, the three feature points not being on the same straight line;

[0235] drive the end printing tool by the robot arm, so that the three feature points on the end printing tool are in contact with corresponding preset reference points on the printing substrate in turn;

[0236] respectively acquire a pose transformation relationship of the robot end effector relative to the robot base when each of the feature points of the end printing tool is in contact with the corresponding reference point;

[0237] calculate a rotation matrix of the coordinate system of the end printing tool relative to the coordinate system of the robot end effector according to the positional relationship of any two feature points of the three feature points in the coordinate system of the end printing tool, and the pose transformation relationship of the robot end effector relative to the robot base when each of the feature points of the end printing tool is in contact with the corresponding reference point.

[0238] Optionally, the acquiring the pose transformation relationship of the coordinate system of the printing substrate relative to the coordinate system of the robot base according to the pose of the coordinate system of the end printing tool relative to the coordinate system of the robot base comprises:

[0239] determine three feature points on the printing substrate, and a positional relationship of any two feature points of the three feature points in the coordinate system of the printing substrate, the three feature points not being on the same straight line;

[0240] drive the end printing tool to be in contact with the three feature points respectively by the robot arm;

[0241] respectively acquire a pose transformation relationship of the robot end effector relative to the robot base when the end printing tool is in contact with each of the feature points;

[0242] According to the positional relationship between any two of the three feature points in the coordinate system of the printing substrate, and the pose transformation relationship of the end of the mechanical arm relative to the base of the mechanical arm when the end printing tool contacts each of the feature points, a pose transformation relationship of the coordinate system of the printing substrate relative to the coordinate system of the base of the mechanical arm is determined.

[0243] The present application also provides a path planning device, as shown in Figure 16 Figure 16 is a schematic diagram of an embodiment of the path planning device of the present application. The path planning device 1600 comprises a first processor 1601 and a first memory 1602, and the first memory 1602 stores executable code, which, when executed by the first processor 1601, causes the first processor 1601 to perform any of the path planning methods described above.

[0244] The present application also provides an additive manufacturing device, as shown in Figure 17 Figure 17 is a schematic diagram of an embodiment of the path planning device of the present application. The additive manufacturing device 1700 comprises a second processor 1701 and a second memory 1702, and the second memory 1702 stores executable code, which, when executed by the second processor 1701, causes the second processor 1701 to perform any of the additive manufacturing methods described above.

[0245] Optionally, the additive manufacturing device further comprises a multi-axis mechanical arm fixed on the base of the mechanical arm, and an end printing tool located at the end of the multi-axis mechanical arm; the multi-axis mechanical arm is used to drive the end printing tool to print target material on the printing substrate.

[0246] Alternatively, the present application can also be implemented as a computer readable storage medium (or non-transitory machine readable storage medium or machine readable storage medium) having stored executable code (or computer program or computer instruction code) thereon, which, when executed by a processor of an electronic device (such as an additive manufacturing device), causes the processor to perform part or all of the steps of the path planning method or the additive manufacturing method according to the present application.

[0247] ​​Having described various embodiments of the application, it is to be understood that the above description is meant to be illustrative only, and that many modifications and variations of the embodiments described herein are possible. It is therefore to be understood that within the scope of the appended claims, and their equivalents, many alternatives to the embodiments described herein are possible. The selection of terms to be used in the description is not intended to limit the scope of the embodiments described herein, but rather to best explain the principles of the embodiments, practical application, or improvement over the technology in the art, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method of additive manufacturing, characterized by, The method comprises the following steps: obtaining a plurality of three-dimensional filling paths of printing surfaces of a target structure; converting the plurality of three-dimensional filling paths of the printing surfaces into machine motion trajectories respectively; printing target material on a printing base by using a multi-axis robot arm to drive an end printing tool located at the end of the multi-axis robot arm according to the machine motion trajectories; wherein the step of obtaining the plurality of three-dimensional filling paths of the printing surfaces of the target structure comprises: obtaining structural parameters of a target structure, the target structure being a reinforced shell structure comprising a shell and reinforcing ribs located on the surface of the shell; generating a plurality of printing surfaces according to the structural parameters of the target structure, wherein the target structure comprises different first and second structures, the plurality of printing surfaces comprise a first printing surface corresponding to the first structure and a second printing surface corresponding to the second structure, and the first structure is the shell and the second structure is the reinforcing rib; mapping the first and second printing surfaces to a two-dimensional plane respectively by using different mapping functions to obtain a first two-dimensional graph and a second two-dimensional graph, including: when the first printing surface is a developable surface, mapping the first printing surface to a two-dimensional plane by using an isometric mapping function to obtain a first two-dimensional graph; or, when the first printing surface is not a developable surface, converting the first printing surface into a combination of at least two developable surfaces, mapping the at least two developable surfaces to a two-dimensional plane respectively by using an isometric mapping function to obtain a first two-dimensional graph, and mapping the second printing surface to a two-dimensional plane by using a conformal mapping function to obtain a second two-dimensional graph; planning filling paths in the first and second two-dimensional graphs respectively to obtain a first two-dimensional filling path and a second two-dimensional filling path, including: planning a filling path in the second two-dimensional graph to obtain a second filling path with a regular graph; mapping the first two-dimensional filling path back to the first printing surface to obtain a three-dimensional filling path of the first printing surface; mapping the second two-dimensional filling path back to the second printing surface to obtain a three-dimensional filling path of the second printing surface.

2. The method of claim 1, wherein, The step of planning filling paths in the first and second two-dimensional graphs respectively to obtain a first two-dimensional filling path and a second two-dimensional filling path comprises: planning a filling path in the first two-dimensional graph by using a full filling method to obtain a first two-dimensional filling path.

3. The method of claim 2, wherein, The three-dimensional filling paths of the plurality of printing surfaces comprise a first printing path representation, and the first printing path representation comprises three-dimensional coordinates and normal vectors of a plurality of discrete path points in a printing base coordinate system; The step of converting the plurality of three-dimensional filling paths of the printing surfaces into machine motion trajectories respectively comprises: obtaining a pose conversion relationship between a coordinate system of an end printing tool and a coordinate system of a robot base of the multi-axis robot arm, and a pose conversion relationship between a coordinate system of a printing base and the coordinate system of the robot base; According to a pose conversion relationship of a coordinate system of the end printing tool relative to a coordinate system of the mechanical arm base, the first printing path representation is converted into a second printing path representation in the coordinate system of the end printing tool; According to a pose conversion relationship of a coordinate system of the printing substrate relative to a coordinate system of the mechanical arm base, the second printing path representation is converted into a machine motion trajectory in the coordinate system of the mechanical arm base.

4. The method of claim 3, wherein, The conversion of the first printing path representation into the second printing path representation in the coordinate system of the end printing tool according to the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the mechanical arm base comprises: Taking an i th discrete path point in the first printing path representation as an origin and taking a unitized normal vector as a Z axis of the coordinate system of the end printing tool, a pose of the i th discrete path point in the coordinate system of the end printing tool is constructed, and the second printing path representation comprises a pose of each discrete path point in the coordinate system of the end printing tool.

5. The method of claim 4, wherein, The target material comprises fibers and resin, and the method further comprises: Obtaining a cross-section parameter and a printing speed of a single-channel printing sample; Determining a feeding rate of the fibers and a feeding rate of the resin according to the cross-section parameter and the printing speed; The printing of the target material on the printing substrate by the multi-axis mechanical arm with the end printing tool located at the end of the multi-axis mechanical arm comprises: Printing the target material on the printing substrate according to the feeding rate of the fibers and the feeding rate of the resin.

6. The method of claim 5, wherein, The method further comprises: Obtaining a fiber correction coefficient, and correcting the fiber feeding rate according to the fiber correction coefficient, The printing of the target material on the printing substrate by the multi-axis mechanical arm with the end printing tool located at the end of the multi-axis mechanical arm comprises: printing the fibers according to the corrected fiber feeding rate; And / or, The method further comprises: obtaining a resin correction coefficient, and correcting the resin feeding rate according to the resin correction coefficient, The printing of the target material on the printing substrate by the multi-axis mechanical arm with the end printing tool located at the end of the multi-axis mechanical arm comprises: printing the resin according to the corrected resin feeding rate.

7. The method of claim 6, wherein, The corrected fiber feeding rate is less than or equal to the fiber feeding rate before correction, and the corrected resin feeding rate is greater than or equal to the resin feeding rate before correction.

8. The method according to any one of claims 5 to 7, characterized in that, The obtaining of the pose conversion relationship of the coordinate system of the end printing tool relative to the coordinate system of the mechanical arm base of the multi-axis mechanical arm and the pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the mechanical arm base further comprises: A first pose conversion relationship is obtained, which is a pose conversion relationship of a coordinate system of an end printing tool relative to a coordinate system of a mechanical arm end, wherein the mechanical arm end is located at an end of a mechanical arm fixed on a mechanical arm base and is used to move the end printing tool so that the end printing tool prints materials on a printing substrate; obtain a second pose transformation relationship, the second pose transformation relationship being a pose transformation relationship of a coordinate system of the robot arm end relative to a coordinate system of the robot arm base; determine, according to the first pose transformation relationship and the second pose transformation relationship, a pose transformation relationship of a coordinate system of the end printing tool relative to a coordinate system of the robot arm base; determine, according to the pose transformation relationship of the coordinate system of the end printing tool relative to the coordinate system of the robot arm base, a pose transformation relationship of a coordinate system of the printing substrate relative to the coordinate system of the robot arm base.

9. The method of claim 8, wherein, The obtaining of the first pose transformation relationship comprises: driving the end printing tool to sequentially contact a same reference point on the printing substrate at least twice in different postures by the robot arm; obtaining a pose transformation relationship of a coordinate system of the robot arm end relative to a coordinate system of the robot arm base at each contact; calculating a position vector of a coordinate system of the end printing tool relative to a coordinate system of the robot arm end according to the pose transformation relationships of the coordinate system of the robot arm end relative to the coordinate system of the robot arm base in the at least twice contacts.

10. The method of claim 8, wherein, The obtaining of the first pose transformation relationship comprises: determining three feature points on the end printing tool, and a positional relationship of any two feature points of the three feature points in a coordinate system of the end printing tool, the three feature points not being on a same straight line; driving the end printing tool by the robot arm, so that the three feature points on the end printing tool sequentially contact corresponding preset reference points on the printing substrate; respectively obtaining a pose transformation relationship of the robot arm end relative to the robot arm base when each feature point of the end printing tool contacts a corresponding reference point; calculating a rotation matrix of a coordinate system of the end printing tool relative to a coordinate system of the robot arm end according to the positional relationship of any two feature points of the three feature points in the coordinate system of the end printing tool, and the pose transformation relationships of the robot arm end relative to the robot arm base when each feature point of the end printing tool contacts a corresponding reference point.

11. The method of claim 8, wherein, The obtaining of the first pose transformation relationship comprises: determining three feature points on the end printing tool, and a positional relationship of any two feature points of the three feature points in a coordinate system of the end printing tool, the three feature points not being on a same straight line; driving the end printing tool by the robot arm, so that the three feature points on the end printing tool sequentially contact corresponding preset reference points on the printing substrate; respectively obtaining a pose transformation relationship of the robot arm end relative to the robot arm base when each feature point of the end printing tool contacts a corresponding reference point; calculating a rotation matrix of a coordinate system of the end printing tool relative to a coordinate system of the robot arm end according to the positional relationship of any two feature points of the three feature points in the coordinate system of the end printing tool, and the pose transformation relationships of the robot arm end relative to the robot arm base when each feature point of the end printing tool contacts a corresponding reference point. According to a positional relationship of any two of the three feature points in a coordinate system of the printing substrate and a pose conversion relationship of the mechanical arm end relative to the mechanical arm base when the end printing tool contacts each of the feature points, a pose conversion relationship of the coordinate system of the printing substrate relative to the coordinate system of the mechanical arm base is determined.

12. An additive manufacturing apparatus, characterized by Comprise: A second acquisition module for acquiring three-dimensional filling paths of a plurality of printing surfaces of a target structure; A conversion module for converting the three-dimensional filling paths of the plurality of printing surfaces into machine motion trajectories respectively; A printing module for printing a target material on a printing substrate by using a multi-axis mechanical arm to drive an end printing tool located at the end of the multi-axis mechanical arm according to the machine motion trajectories; Wherein, the second acquisition module comprises: A first acquisition module for acquiring structure parameters of a target structure, the target structure being a reinforced shell structure, the reinforced shell structure comprising a shell and a reinforcing rib located on the surface of the shell; A generation module for generating a plurality of printing surfaces according to the structure parameters of the target structure, wherein the target structure comprises different first and second structures, the plurality of printing surfaces comprising a first printing surface corresponding to the first structure and a second printing surface corresponding to the second structure, the first structure being the shell, and the second structure being the reinforcing rib; A mapping module for mapping the first and second printing surfaces to a two-dimensional plane respectively using different mapping functions to obtain a first two-dimensional graph and a second two-dimensional graph, comprising: when the first printing surface is a developable surface, using an isometric mapping function to map the first printing surface to a two-dimensional plane to obtain a first two-dimensional graph; or, when the first printing surface is not a developable surface, converting the first printing surface into a combination of at least two developable surfaces, using an isometric mapping function to map the at least two developable surfaces to a two-dimensional plane respectively to obtain a first two-dimensional graph; using a conformal mapping function to map the second printing surface to a two-dimensional plane to obtain a second two-dimensional graph; A planning module for planning filling paths in the first and second two-dimensional graphs respectively to obtain a first two-dimensional filling path and a second two-dimensional filling path, comprising: planning a filling path in the second two-dimensional graph to obtain a second filling path with a regular graph; The mapping module is further used to map the first two-dimensional filling path back to the first printing surface to obtain a three-dimensional filling path of the first printing surface; The mapping module is further used to map the second two-dimensional filling path back to the second printing surface to obtain a three-dimensional filling path of the second printing surface.

13. An additive manufacturing apparatus, characterized by Comprise a second memory and a second processor, the second memory storing executable code, when the executable code is processed by the second processor, the second processor executes the method of any one of claims 1-11.

14. The additive manufacturing apparatus of claim 13, wherein, Further comprise a multi-axis mechanical arm fixed on a mechanical arm base, and an end printing tool located at the end of the multi-axis mechanical arm; The multi-axis robotic arm is configured to move the end printing tool to print a target material on a printing substrate.

15. A computer-readable storage medium, characterized in that, executable code that, when executed by a processor of an electronic device, causes the electronic device to perform the additive manufacturing method of any one of claims 1 to 11.

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