Satellite engine protective cover design method based on dot matrix structure

Abstract

The application discloses a satellite engine protective cover design method based on a dot matrix structure, and comprises the following steps: S1, inputting three-dimensional models of a special-shaped support, an engine and an interference object, and calculating a design space of the protective cover; S2, dividing the protective cover into two parts of a cover body and a base, confirming entity regions and dot matrix regions after function analysis; S3, constructing a dot matrix unit library, selecting a filling unit according to a function analysis result, and realizing shape-following filling of the dot matrix unit through a dot matrix unit filling algorithm; and S4, integrating the dot matrix structure and the entity structure to form a final protective cover model for printing, and quickly realizing design intention and product manufacturing through a 3D printing technology. The application can develop a 3D printing dot matrix structure satellite engine protective cover product integrating the functions of light weight, easy dismounting, good visibility, excellent protection, high interface matching degree and the like.

Description

Technical Field

[0001] This invention relates to the field of satellite assembly tooling product design technology, and in particular to a design method for a satellite engine protective cover based on a dot matrix structure. Background Technology

[0002] A lattice structure can be considered a porous structure composed of a large number of identical lattice units arranged periodically in some form. Compared with other types of porous structures (including wood and foamed metal), lattice structures composed of interconnected rod systems are easier to customize and exhibit superior performance. Therefore, lattice structures have received considerable research attention and are used to replace traditional materials to achieve weight reduction and multifunctional integration. Lattice structures themselves possess many unique properties, such as ultralight weight, high strength-to-stiffness ratio, thermal insulation, efficient heat exchange, shock absorption, cooling, and biocompatibility, and are widely used in impact / explosion systems, or as heat dissipation media, acoustic vibration, microwave absorption structures, and drive systems. The performance of this structure offers high design flexibility; by adjusting the relative density of the lattice, the configuration of the unit cells, and the dimensions of the connecting rods, a perfect balance of strength, stiffness, toughness, durability, static properties, and dynamic properties can be achieved. Combined with the ability of additive manufacturing to create complex structures, designers can focus more on the product itself, which opens up a wider range of applications for additive manufacturing lattice structures.

[0003] The onboard engines of small satellites are used for attitude control and adjustment. They are typically mounted on the outer surface of the satellite to expel exhaust gases during operation, usually near the edges of the payload bay floor and platform floor. After the satellite's deck is closed, the engine nozzles protrude from the side and bottom panels, exposed to the outside. Without protection, the engines are at risk of being bumped or damaged during deck closure and surface handling. Because the engines are relatively expensive and require precise installation, any collision during operation can compromise the original installation accuracy and severely delay research and production tasks. Therefore, it is necessary to install engine protective covers to protect the exposed engine equipment from collisions during human operation.

[0004] However, in the satellite assembly process, satellite side panels require frequent installation and removal. Existing engine protective covers are installed on the outer surface of the structural side panels, requiring the engine protective cover to be removed before each side panel installation or removal. Furthermore, during precise engine testing, the engine's own nozzle protective cap needs to be removed, also necessitating the removal of the engine protective cover before restoration. These repeated disassembly and reassembly tasks cause inconvenience to the assembly process. Therefore, there is a need to design a new, easily removable engine protective cover that protects the engine while improving assembly efficiency. Moreover, the application of new 3D-printed irregular structural components, such as thruster brackets, is becoming increasingly widespread. Traditional protective covers no longer meet the interface requirements of these new brackets. Therefore, there is an urgent need to develop a new 3D-printed protective cover to match these requirements. However, the diverse types and interfaces of various irregular brackets result in a huge workload for protective cover product design, and the integrated design and model building method for lattice-structured protective covers remains a challenge. Therefore, this paper aims to study a protective cover product design method based on conformal lattice structure to meet the rapid development needs of future personalized protective cover products.

[0005] Regarding the design research of engine protective covers, the literature "Chinese Invention Patent Application Publication No. CN105059570B" proposes a design method for a non-disassembly engine protective cover for small satellites. The cylindrical protective cover can be directly installed on the engine bracket flange, and can pass through the structural through-hole when installing and removing the side plate, avoiding the previous work of repeatedly disassembling and installing the protective cover due to the disassembly and installation of the structural plate, thus improving the efficiency of the final assembly work.

[0006] Regarding research on the design of lattice structure products, the Chinese invention patent application CN217640206U provides an additive manufacturing lattice sandwich structure for a fuselage door rotating rocker arm handle, offering a practical design solution for fabricating lattice sandwich structures using additive manufacturing processes and expanding the application scenarios of additive manufacturing lattice structures. The Chinese invention patent application CN217609729U introduces biomimetic wave structures and pyramid-shaped lattice structures, filling the layers with glass microspheres to simulate the porous structure of an animal's body. This gives the helmet shell high impact resistance, efficiently absorbing impact energy transmitted through the outer shell to the buffer pad, providing effective protection for the wearer and reducing safety hazards caused by low helmet impact resistance. The Chinese invention patent application CN114954887A discloses a lightweight electric servo motor impact-resistant protective shell based on a three-dimensional rotating lattice structure. The shell uses a three-dimensional lattice structure to create an impact-resistant protective layer, and by adjusting the rotation angle of the unit cells, different initial load-bearing capacities and energy absorption capacities are achieved for the upper and lower cover structures.

[0007] However, the aforementioned research on lattice structures has not been applied to the design of satellite engine protective covers. Summary of the Invention

[0008] The purpose of this invention is to propose a satellite protective cover design method based on a lattice structure. Addressing the rapid development needs of customized protective cover products for various types of irregularly shaped structural components across all models, this invention researches a 3D-printed lattice structure satellite engine protective cover product development method that integrates lightweight, easy assembly and disassembly, excellent visibility, superior protection, and high interface compatibility. A general design process for conformal lattice structure satellite protective cover products is proposed. Based on the design method proposed in this paper, a series of derivative protective cover products are printed using photopolymerization technology, aiming to reduce the risk of damage to critical satellite components during the final assembly stage and improve product safety protection capabilities during satellite assembly.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A design method for a satellite engine protective shield based on a lattice structure includes the following steps:

[0011] S1. Input the 3D model of the irregular support, engine and interference object, and calculate the design space of the protective cover;

[0012] S2. Divide the protective cover into two parts: the cover body and the base. After functional analysis, identify the solid area and the dot matrix area.

[0013] S3. Construct a dot matrix unit library, select filling units based on functional analysis results, and implement conformal filling of dot matrix units through a dot matrix unit filling algorithm.

[0014] S4. Integrate the lattice structure and solid structure to form the final protective cover model for printing. Use 3D printing technology to quickly realize the design intent and product manufacturing. If the manufactured product does not meet the design requirements, return to start the product iteration design until it meets the design requirements, then manufacture it and put it into production.

[0015] Preferably, in step S2, the solid region is used to create various interfaces to connect different regions; while the dot matrix region is used to fill the dot matrix units to realize the observation of the engine status inside the housing and to have a certain load-bearing capacity.

[0016] Preferably, in step S3, since it is difficult to directly construct a complex dot matrix wireframe model on the overall dot matrix unit, the dot matrix unit construction principle is used. h Based on group theory, the cubic mesh element is divided using three orthogonal planes orthogonal to the X, Y, and Z axes and six oblique planes bisect the angle between the X, Y, and Z axes, resulting in forty-eight sub-tetrahedra. Based on the distribution of key points on the sub-tetrahedra and their topological relationships, fifteen key points are classified into the following four categories:

[0017] Vertices, that is, the four vertices of a tetrahedron, are denoted as V = {V0, V1, V2, V3};

[0018] The edge point, that is, the midpoint of the six edges of the tetrahedron, is denoted as E = {E0, E1, E2, E3, E4, E5}.

[0019] The centroid of the four faces of a tetrahedron is denoted as F = {F0, F1, F2, F3}.

[0020] The volume point, i.e. the centroid of the tetrahedron, is denoted as T = {T0};

[0021] The set P consisting of key points is denoted as P = {p | p ∈ V ∪ E ∪ F ∪ T};

[0022] The faces corresponding to the four vertices {V0, V1, V2, V3} are denoted as {H0, H1, H2, H3}, respectively. The face H0 corresponding to the center V0 of the cube is located on the surface of the cube. H0 is called the interface. Based on the key points on the interface element H0 and the connectability between the lattice elements, the lattice elements are divided into seven series, namely {V1, V2, V3, E0, E1, E2, F0}.

[0023] The dot matrix unit library constructed in step S3 has the following properties: dot matrix units of the same series have the same interface dot elements; a dot matrix unit may belong to different series.

[0024] All candidate lattice elements that meet the constraints are summarized, with a total of 217 lattice types in the V1, V2, and V3 series, 159 lattice types in the E1, E2, and E3 series, and 112 lattice types in the F0 series.

[0025] Preferably, the dot matrix single-fill in step S3 includes:

[0026] Based on the functional analysis results, fill units are selected, and the lattice unit filling algorithm is used to achieve conformal filling of the lattice units, as detailed below:

[0027] The spatial hexahedral mesh generation algorithm has been maturely applied to existing finite element analysis software. By discretizing the solid into a series of general hexahedral meshes, and further selecting appropriate regular hexahedral lattice elements from the lattice element library to fill the standard hexahedral mesh, a conformal lattice structure with complete structure and high connection strength can be generated.

[0028] A reference coordinate system (ξ, η, ζ) is defined to describe the regular hexahedral elements in the lattice element library, while the general hexahedral mesh generated by the hexahedral meshing algorithm is described by the physical coordinate system (x, y, z). For a point X(ξ, η, ζ) in the reference coordinate system, its interpolation function weights are:

[0029]

[0030] Define the fill function using the interpolation function weights:

[0031]

[0032] To map any point X in the reference coordinate system to a vertex with coordinate X'. i The points X(x,y,z) in the general hexahedron (i=1,…8) are then used to fill the general hexahedron with lattice elements, while still maintaining the topological configuration of the lattice elements.

[0033] Preferably, in step S4, the dot matrix structure and the solid structure are integrated to form the final protective cover model for printing, a special red resin material is prepared, and a red conformal dot matrix structure protective cover is manufactured using a photopolymerization 3D printer.

[0034] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0035] 1. The base cover interface in this application adopts a 3-slot design, which allows for quick assembly and disassembly of the cover through simple rotation.

[0036] 2. The cover area in this application adopts a dot matrix structure, which can significantly reduce the weight of the cover. Compared with the traditional thin-walled structure, it also has excellent radial load-bearing capacity. By adjusting the density of the dot matrix structure, a good observation field of view can be achieved for monitoring the engine status.

[0037] 3. This application adopts a dot matrix filling algorithm, which can fill cubic regular dot matrix units into irregular hexahedral mesh, thereby realizing the conformal design of the dot matrix structure and further improving the mechanical performance of the protective cover. This application can develop a 3D printed dot matrix structure satellite engine protective cover product that integrates functions such as lightweight, easy disassembly and assembly, good visibility, excellent protection, and high interface compatibility. Attached Figure Description

[0038] Figure 1 The flowchart illustrates the main steps of a satellite engine protective shield design method based on a lattice structure according to an embodiment of the present invention.

[0039] Figure 2 A flowchart illustrating the design process of the satellite 10N engine protective shield according to an embodiment of the present invention is shown.

[0040] Figure 3 A schematic diagram illustrating the distribution and topological relationship of key points in a cubic mesh segmentation according to an embodiment of the present invention is shown.

[0041] Figure 4 An example diagram of a dot matrix unit library provided according to an embodiment of the present invention is shown;

[0042] Figure 5 A flowchart of the dot matrix cell filling process according to an embodiment of the present invention is shown. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Please see Figure 1-5 The present invention provides a technical solution:

[0045] A design method for a satellite engine protective shield based on a lattice structure includes the following steps:

[0046] S1. Input the 3D model of the irregular support, engine and interference object, and calculate the design space of the protective cover;

[0047] S2. Divide the protective cover into two parts: the cover body and the base. After functional analysis, identify the solid area and the dot matrix area. The solid area is used to create various interfaces to connect different areas; while the dot matrix area is used to fill the dot matrix units to realize the observation of the engine status inside the cover body and has a certain load-bearing capacity.

[0048] S3. Construct a dot matrix unit library, select filling units based on functional analysis results, and implement conformal filling of dot matrix units through a dot matrix unit filling algorithm.

[0049] S4. Integrate the lattice structure and solid structure to form the final protective cover model for printing. Use 3D printing technology to quickly realize the design intent and product manufacturing. If the manufactured product does not meet the design requirements, return to start the product iteration design until it meets the design requirements, then manufacture it and put it into production.

[0050] Specifically, such as Figure 2 As shown, taking a 10N satellite engine protective cover as an example, the technical solution proposed in this invention realizes the development of a dot-matrix structure protective cover. In step S2, the solid area is used to create various interfaces to connect different areas; while the dot-matrix area is used to fill the dot-matrix unit to realize the observation of the engine status inside the cover and to have a certain load-bearing capacity.

[0051] Specifically, such as Figure 3 As shown, in step S3, since it is difficult to directly construct a complex dot matrix wireframe model on the overall dot matrix unit, the dot matrix unit construction principle O is used instead. hBased on group theory, the cubic mesh element is divided using three orthogonal planes orthogonal to the X, Y, and Z axes and six oblique planes bisect the angle between the X, Y, and Z axes, resulting in forty-eight sub-tetrahedra. Based on the distribution of key points on the sub-tetrahedra and their topological relationships, fifteen key points are classified into the following four categories:

[0052] Vertices, that is, the four vertices of a tetrahedron, are denoted as V = {V0, V1, V2, V3};

[0053] The edge point, that is, the midpoint of the six edges of the tetrahedron, is denoted as E = {E0, E1, E2, E3, E4, E5}.

[0054] The centroid of the four faces of a tetrahedron is denoted as F = {F0, F1, F2, F3}.

[0055] The volume point, i.e. the centroid of the tetrahedron, is denoted as T = {T0};

[0056] The set P consisting of key points is denoted as P = {p | p ∈ V ∪ E ∪ F ∪ T};

[0057] The faces corresponding to the four vertices {V0, V1, V2, V3} are denoted as {H0, H1, H2, H3}, respectively. The face H0 corresponding to the center V0 of the cube is located on the surface of the cube. H0 is called the interface. Based on the key points on the interface element H0 and the connectability between the lattice elements, the lattice elements are divided into seven series, namely {V1, V2, V3, E0, E1, E2, F0}.

[0058] Specifically, such as Figure 4 As shown, the dot matrix unit library constructed in step S3 has the following properties: dot matrix units of the same series have the same interface dot elements; a dot matrix unit may belong to different series.

[0059] A total of 217 lattice types are summarized for the V1, V2, and V3 series, 159 lattice types are summarized for the E1, E2, and E3 series, and 112 lattice types are summarized for the F0 series.

[0060] The dot matrix single-fill in step S3 includes:

[0061] Based on the functional analysis results, fill units are selected, and the lattice unit filling algorithm is used to achieve conformal filling of the lattice units, as detailed below:

[0062] The spatial hexahedral mesh generation algorithm has been maturely applied to existing finite element analysis software. By discretizing the solid into a series of general hexahedral meshes, and further selecting appropriate regular hexahedral lattice elements from the lattice element library to fill the standard hexahedral mesh, a conformal lattice structure with complete structure and high connection strength can be generated.

[0063] A reference coordinate system (ξ, η, ζ) is defined to describe the regular hexahedral elements in the lattice element library, while the general hexahedral mesh generated by the hexahedral meshing algorithm is described by the physical coordinate system (x, y, z). For a point X(ξ, η, ζ) in the reference coordinate system, its interpolation function weights are:

[0064]

[0065] Specifically, such as Figure 5 As shown, the fill function is defined by the interpolation function weights:

[0066]

[0067] To map any point X in the reference coordinate system to a vertex with coordinate X'. i The points X(x,y,z) in the general hexahedron (i=1,…8) are then used to fill the general hexahedron with lattice elements, while still maintaining the topological configuration of the lattice elements.

[0068] In step S4, the lattice structure and solid structure are integrated to form the final protective cover model for printing. Special red resin material is prepared and a red conformal lattice structure protective cover is manufactured using a photopolymer 3D printer. If the manufactured product does not meet the design requirements, the process returns to the beginning of product iteration design until it meets the design requirements, after which it is manufactured and put into production.

[0069] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A design method for a satellite engine protective shield based on a lattice structure, characterized in that, Includes the following steps: S1. Input the 3D model of the irregular support, engine and interference object, and calculate the design space of the protective cover; S2. Divide the protective cover into two parts: the cover body and the base. After functional analysis, identify the solid area and the dot matrix area. S3. Construct a dot matrix unit library, select filling units based on functional analysis results, and implement conformal filling of dot matrix units through a dot matrix unit filling algorithm. S4. Integrate the lattice structure and solid structure to form the final protective cover model for printing. Use 3D printing technology to quickly realize the design intent and product manufacturing. If the manufactured product does not meet the design requirements, return to start the product iteration design until it meets the design requirements, then manufacture it and put it into production. In step S3, since it is difficult to directly construct a complex dot matrix wireframe model on the overall dot matrix unit, the principle of dot matrix unit construction is used. Based on group theory, the cubic mesh element is divided using three orthogonal planes orthogonal to the X, Y, and Z axes and six oblique planes bisect the angle between the X, Y, and Z axes, resulting in forty-eight sub-tetrahedra. Based on the distribution of key points on the sub-tetrahedra and their topological relationships, fifteen key points are classified into the following four categories: Vertex, that is, the four vertices of a tetrahedron, denoted as . ; An edge point, that is, the midpoint of the six edges of a tetrahedron, is denoted as . ; A pastry, specifically the centroid of the four faces of a tetrahedron, is denoted as . ; The center of mass of a tetrahedron is denoted as . ; The set P consisting of key points is denoted as ; Four vertices The corresponding faces are denoted as The center of the cube Corresponding face Located on the surface of a cube, it is called For the interface, based on the interface element The key points and the connectivity between lattice units categorize lattice units into seven major series, namely... ; The dot matrix unit library constructed in step S3 has the following properties: dot matrix units of the same series have the same interface dot elements; a dot matrix unit may belong to different series. A total of 217 lattice types were identified across the V1, V2, and V3 series, and 159 lattice types across the E1, E2, and E3 series, satisfying all the constraints. The series includes a total of 112 dot matrix types; The lattice unit filling includes: Based on the functional analysis results, fill units are selected, and the lattice unit filling algorithm is used to achieve conformal filling of the lattice units, as detailed below: The spatial hexahedral mesh generation algorithm has been maturely applied to existing finite element analysis software. By discretizing the solid into a series of hexahedral meshes, and further selecting regular hexahedral lattice elements from the lattice element library to fill the standard hexahedral mesh, a conformal lattice structure with complete structure and high connection strength can be generated. A reference coordinate system (ξ, η, ζ) is defined to describe the regular hexahedral elements in the lattice element library, while the hexahedral mesh generated by the hexahedral meshing algorithm is described by the physical coordinate system (x, y, z). For points in the reference coordinate system... X (ξ,η,ζ), whose interpolation function weights are: Define the fill function using the interpolation function weights: Achieve the goal of starting from any point in the reference coordinate system X Mapped to vertex coordinates ， The points X(x,y,z) in the hexahedron are then used to fill the hexahedron with lattice elements, while still maintaining the topological configuration of the lattice elements.

2. The satellite engine protective cover design method based on a dot-matrix structure according to claim 1, characterized in that, In step S2, the physical region is used to create various interfaces to connect different regions; while the dot matrix region is used to fill the dot matrix units to realize the observation of the engine status inside the housing and to have a certain load-bearing capacity.

3. The satellite engine protective cover design method based on a dot-matrix structure according to claim 1, characterized in that, In step S4, the lattice structure and the solid structure are integrated to form the final protective cover model for printing. The proportioned red resin material is used to manufacture the red conformal lattice structure protective cover using a photopolymerization 3D printer.

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