An expandable modular thin-shell structure for on-orbit assembly

Abstract

The application discloses an unfoldable modular thin-shell structure for on-orbit assembly, and belongs to the technical field of truss structures for on-orbit assembly in space. The unfoldable modular thin-shell structure is connected by six module units, and the module unit comprises a carbon fiber thin shell, a driving motor, a rotating shaft, a limiting cover, a connector and a shell. Adjacent module units are connected through the unfoldable carbon fiber thin shell to form an equilateral hexagonal truss structure. The module units control the thin shell unfolding length through the built-in motor, and the size of the hexagonal truss can be flexibly changed. The application improves the flexibility and space utilization rate of the truss structure, and solves the problems of large required carrying space and difficult on-orbit assembly of the traditional truss structure.

Description

Technical Field

[0001] This invention pertains to on-orbit assembly technology for large space structures in aerospace, specifically involving a deployable modular thin-shell structure for on-orbit assembly. Background Technology

[0002] With the development of on-orbit servicing technology, on-orbit assembly has become a research hotspot in the field of aerospace science and engineering in recent years. On-orbit assembly and maintenance technology has become the best way to realize ultra-large space structures. This technology will break through the limitations of launch vehicle envelope and propulsion capabilities. On-orbit assembly involves sequentially assembling structural or functional modules that have been launched into orbit once or multiple times into the desired large space system. It requires the ability to connect, replace, construct, combine, or reassemble large spacecraft in orbit, thereby realizing more complex and diverse large space structures.

[0003] In order to realize the practical engineering application of large-scale space structures, major spacefaring nations are actively exploring on-orbit technologies. The assembly targets are gradually shifting from component level to cross-scale, high-precision, and structurally integrated space facilities. However, most current technologies can only achieve small folding and unfolding of assembly units, which have poor load-bearing capacity after unfolding. There is an urgent need to design folding and unfolding units with large folding and unfolding capacity and high rigidity. Summary of the Invention

[0004] This invention provides a deployable modular thin-shell structure for on-orbit assembly, which solves the problems of small foldable and retractable units and poor load-bearing capacity after deployment in the prior art.

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

[0006] A deployable modular thin-shell structure for on-orbit assembly consists of six modular units forming an equilateral hexagonal structure, with adjacent modular units connected by carbon fiber thin shells and connectors.

[0007] One end of the carbon fiber shell is connected to the rotating shaft of the module unit, and the other end is connected to the connector of the adjacent unit. The connector is fixed on one side of the module unit shell. The stepper motor provides power to the rotating shaft system of the module unit, and the limiting cover limits the curled part.

[0008] The carbon fiber shell, in its naturally extended state, is an arc-shaped rod with a central angle of 120 degrees (radius 2cm), and round holes are machined at both ends for fixing; the shell can be rolled up under the action of the rotating shaft torque;

[0009] The shaft has circular flanges on both sides, and the main body of the shaft is an irregular cylinder. With the help of specific pressure plates and bolts, it can fix the thin shell. The shaft has a central hole, and one end is connected to a clamping coupling.

[0010] The diameter of the rotating shaft was determined experimentally. A series of rotating shaft diameters were set, and the adhesion of the rolled-up part of the thin shell and the stability of the stretched part were measured and compared to select the optimal diameter.

[0011] The limiting cover is fixed to the upper side of the rotating shaft and connected to the motor base. It is U-shaped when viewed from the side, close to the rotating shaft, and has a special opening on the protruding side of the thin shell.

[0012] The optical axis passes through the rotating shaft, and both ends are supported by bearings embedded in the bearing housing. The bearing housing is fixed to the upper part of the motor base by bolts, and the 42 stepper motor is fixed to the lower part of the motor base. The torque is transmitted between the motor shaft and the optical axis through a synchronous belt.

[0013] The optical shaft is positioned and fixed by means of an isolation column, a metal gasket, a coupling, and a synchronous pulley;

[0014] The module unit housing consists of an upper shell and a lower shell. The lower shell is connected to the motor mount by bolts, and the front and rear spaces are used for placing electronic components (and power supply system). The upper shell has an opening on the front for the insertion of connectors from adjacent units. The upper and lower shells are connected by four long bolts.

[0015] Beneficial effects: This invention provides a deployable modular thin-shell structure for on-orbit assembly, which has the following advantages compared with the prior art:

[0016] 1. The thin-shell structure of the present invention is composed of six deployable modular units connected by arc-shaped carbon fiber thin shells. One end of the carbon fiber thin shell is connected to the rotating shaft, and the other end is fixed by the connector of the adjacent unit. After the units are connected, the included angle between the adjacent rod-shaped thin shells is 120 degrees, thereby forming a stable, high-strength, and easily expandable equilateral hexagonal truss structure to meet the needs of truss structure operation in space.

[0017] 2. The arc-shaped carbon fiber thin shell is in the shape of an arc rod when naturally stretched. It has certain rigidity, bending strength, tensile strength and stability. When subjected to torque at one end, it can be rolled up or stretched along the rod direction. This characteristic meets the requirement that the part can be unfolded while having certain mechanical properties.

[0018] 3. The stepper motor drives the rotating shaft via a synchronous belt. The shaft and the motor are respectively mounted on the upper and lower sides of the motor base. Compared with direct coupling drive, this reduces the lateral space required by the unit, which is conducive to structural compaction and improves the structural extension ratio.

[0019] 4. The stepper motor provides power to the shaft, causing the thin shell to curl or extend, thereby changing the extension length of the carbon fiber thin shell. During transport, each unit's thin shell is completely curled up, and each unit's connector is inserted into the hexagonal shell of the adjacent unit. The shells of the adjacent units are tightly attached, the structure is compacted, and the space occupied is minimized. After the track is in place, each unit's motor moves simultaneously, and the six carbon fiber thin shells gradually extend, the structure unfolds, and the space occupied is maximized. This unfoldable characteristic improves the space utilization and flexibility of the structure.

[0020] 5. The limiting cover is installed on the upper side of the rotating shaft to limit the curled part of the carbon fiber shell and prevent the shell from spreading out (so that the shell is in close contact with the rotating shaft), while also providing a certain degree of protection for the carbon fiber shell.

[0021] 6. The thin-shell structure of this invention is modularly designed, which facilitates assembly and expansion. After being processed and manufactured on the ground, the units can be connected, and most of the assembly and debugging can be completed at the same time, reducing the time for on-orbit assembly and debugging, and enabling the truss structure to be put into operation quickly. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the module unit connection structure of the deployable modular thin-shell structure used for on-orbit assembly in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the collapsed state structure of the deployable modular thin-shell structure used for on-orbit assembly in an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the unfolded state of the deployable modular thin-shell structure used for on-orbit assembly in an embodiment of the present invention.

[0025] Figure 4 This is an exploded view of a modular unit component of an on-orbit assembly-compatible thin-shell structure, as shown in an embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram of the fully extended carbon fiber thin shell structure of the deployable modular thin shell structure used for on-orbit assembly in an embodiment of the present invention.

[0027] Figure 6 This is a schematic diagram of the coiled state of the carbon fiber thin shell portion of the deployable modular thin shell structure used for on-orbit assembly in an embodiment of the present invention.

[0028] Figure 7 This is a schematic diagram of the rotating shaft structure of the deployable modular thin-shell structure used for on-orbit assembly in an embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of the connector structure of the deployable modular thin-shell structure used for on-orbit assembly in an embodiment of the present invention;

[0030] Figure 9 This is a schematic diagram of the limiting cover structure of the deployable modular thin-shell structure used for on-orbit assembly in an embodiment of the present invention;

[0031] In the diagram, 1-module unit; 2-carbon fiber shell; 3-connector; 4-upper shell; 5-lower shell; 6-limiting cover; 7-rotating shaft; 8-fixed cover; 9-bearing seat; 10-motor seat; 11-optical shaft; 12-coupling; 13-isolation column; 14-bearing; 15-shield; 16-fixing ring; 17-synchronous pulley; 18-synchronous belt; 19-42-stepper motor; 31-connector body; 32-arc-surface pressure block. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0033] Example 1

[0034] like Figure 1 As shown, a deployable modular thin-shell structure for on-orbit assembly is formed by connecting six module units 1 to form an equilateral hexagonal structure through carbon fiber thin shells 2 and connectors 3; one end of the carbon fiber thin shell 2 between two adjacent module units 1 is connected to the module unit 1, and the other end is connected to the connector 3 installed on the side of the adjacent module unit 1.

[0035] like Figure 4 As shown, module unit 1 includes an upper shell 4, a lower shell 5, a limiting cover 6, a rotating shaft 7, a fixing cover 8, a bearing seat 9, a motor seat 10, an optical shaft 11, a coupling 12, an isolation column 13, a bearing 14, a gasket 15, a retaining ring 16, a synchronous pulley 17, and a synchronous belt 18.

[0036] The upper shell 4 and the lower shell 5 are connected by four symmetrically arranged long bolts;

[0037] Connector 3 is inserted into one side of the upper shell 4, which is at a 120-degree angle to the side connecting the carbon fiber shell 2, so that the module unit can be in the shape of an equilateral hexagon.

[0038] like Figure 7As shown, the rotating shaft system includes several parts, namely, a rotating shaft 7, an optical shaft 11, a coupling 12, a separating column 13, a bearing 14, a gasket 15, a retaining ring 16, and a synchronous pulley 17; the optical shaft 11 passes through the rotating shaft 7, the coupling 12, the separating column 13, the bearing 14, and the gasket 15; the coupling 12 is embedded in the rotating shaft 7 and connected to the optical shaft 11, fixing the rotating shaft 7 to the optical shaft 11 by a clamping method; both ends of the optical shaft 11 are supported by the bearings 14; the separating column 13, the bearings 14, and the... Shims 15 are symmetrically installed at both ends of the rotating shaft 7. From the inside out, they are: isolation column 13, bearing 14, and shim 15. The retaining ring 16 is installed at one end of the optical shaft 11 by a set screw, and the synchronous pulley 17 is installed at the other end of the optical shaft 11 by a set screw. The synchronous belt 18 is installed on the synchronous pulley 17. The isolation column 13, retaining ring 16, and synchronous pulley 17 serve a positioning function and, together with the optical shaft 11, can replace the stepped shaft, which helps to reduce the time and cost of processing and manufacturing.

[0039] One end of the carbon fiber shell 2 connected to the module unit 1 is fixed to the rotating shaft 7 by the fixing cover 8; the rotating shaft 7 is supported and mounted on the motor base 10 by the bearing seats 9 at both ends; the 42 stepper motor 19 is mounted on the lower side of the motor base 10; the motor base 10 is mounted to the center inside the lower shell 5 by bolts; the front and rear sides inside the lower shell 5 are the space for placing electronic components (and power supply system).

[0040] like Figure 9 As shown, the limiting cover 6 is U-shaped in side view and is fixed above the rotating shaft 7, close to the rotating shaft 7. The four corners of the bottom are connected to the motor base 10. The limiting cover 6 and the corresponding parts of the upper shell 4 are provided with openings for the carbon fiber shell 2 to extend. The limiting cover 6 is close to the rotating shaft 7 and surrounds the carbon fiber shell 2, which helps to improve the stability of the curled part of the carbon fiber shell 2 and also plays a certain protective role.

[0041] like Figure 2 and Figure 3 As shown, the 42 stepper motors 19 drive the synchronous pulleys 17, which in turn drive the synchronous belt 18 to drive the rotating shaft 7, causing the carbon fiber shell 2 to coil or extend, thus allowing the total space of the equilateral hexagonal structure to be flexibly adjusted; the theoretical formula for calculating the total space is: (Total space specifically refers to the area of ​​the equilateral hexagon enclosed by the centers of each module unit when viewed from above.) When gathering: ; After unfolding: ; During adjustment: ; in, This refers to the total space size when the structure is collapsed. This represents the total space size in the unfolded state. The side length of the equilateral hexagonal prism shell of the module unit; This represents the maximum elongation length of the carbon fiber thin shell. The elongation length of the carbon fiber shell is calculated. 10:1; .

[0042] like Figure 5 As shown, the carbon fiber shell 2 is an arc-shaped rod-shaped shell with a central angle of 120 degrees (radius 2cm) in its natural extended state, and its thickness is 0.2mm.

[0043] like Figure 6 As shown, the carbon fiber shell 2 curls up when an external torque is applied to one end, and the curled part unfolds from the arc surface to the plane and attaches to the side of the rotating shaft.

[0044] like Figure 7 As shown, the side of the rotating shaft 7 has two arc surfaces of unequal diameters. Two threaded holes are symmetrically opened on one arc surface. The fixing cover 8 can press one end of the carbon fiber shell 2 tightly with bolts. The diameter of the arc on the side of the rotating shaft 7 is selected optimally by comparing the stability of the carbon fiber shell 2 during the rolling process, which is beneficial to the adhesion of the rolled part of the carbon fiber shell 2.

[0045] like Figure 8 As shown, the connector 3 is divided into two parts, wherein the arc-shaped pressure block 32 can press one end of the carbon fiber shell 2 onto the connector body 31 by means of bolts.

[0046] The above embodiments are merely preferred embodiments of the present invention and are only used to explain and illustrate the technical solutions of the present invention, not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and such modifications or equivalent substitutions also fall within the scope of the technical solutions of the present invention.

Claims

1. A deployable modular thin-shell structure for on-orbit assembly, characterized in that, The structure comprises six modular units forming an equilateral hexagonal shape. Adjacent modular units are connected by carbon fiber shells and connectors. One end of the carbon fiber shell between two adjacent modular units is connected to the modular unit, and the other end is connected to a connector mounted on the side of the adjacent modular unit. A motor built into each modular unit provides driving force to cause the carbon fiber shell to retract or extend, adjusting the total space of the equilateral hexagonal structure. Each modular unit includes an upper shell, a lower shell, and a rotating shaft system. The upper and lower shells are connected by four symmetrically arranged long bolts. The rotating shaft system is installed within the space formed by the upper and lower shells. The connector is inserted into one side of the upper shell, forming a 120-degree angle with the side connected to the carbon fiber shell, allowing the modular unit to form an equilateral hexagonal shape. The rotating shaft system includes a rotating shaft, an optical shaft, a coupling, a separator, bearings, gaskets, a retaining ring, a synchronous pulley, a synchronous belt, a motor base, and a motor. The optical shaft passes through the rotating shaft. The structure comprises a shaft, coupling, isolating column, bearing, and gasket. The coupling is embedded in the rotating shaft and connects to the optical shaft, fixing the rotating shaft to the optical shaft by a clamping method. Both ends of the optical shaft are supported by bearings. The isolating column, bearing, and gasket are symmetrically installed at both ends of the rotating shaft, arranged from the inside out as follows: isolating column, bearing, gasket. A fixing ring is installed at one end of the optical shaft by a set screw, and a synchronous pulley is installed at the other end of the optical shaft by a set screw. The synchronous belt is installed on the synchronous pulley. The rotating shaft is supported by bearing seats at both ends and installed above a motor base. The motor is installed below the motor base, which is located at the center inside the lower housing. The motor drives the synchronous pulley, thereby driving the synchronous belt to drive the rotating shaft, causing the carbon fiber shell to curl or extend. The end of the carbon fiber shell connected to the module unit is fixed to the rotating shaft by a fixing cover. A limiting cover is installed above the rotating shaft, close to the rotating shaft, to surround the carbon fiber shell.

2. The deployable modular thin-shell structure for on-orbit assembly according to claim 1, characterized in that, The formula for calculating the total spatial size of the equilateral hexagonal structure is as follows: When gathering: , After unfolding: , During adjustment: , in, This refers to the total space size when the structure is collapsed. This represents the total space size in the unfolded state. The side length of the equilateral hexagonal prism shell of the module unit; This represents the maximum elongation length of the carbon fiber thin shell. This refers to the elongation length of the carbon fiber shell.

3. The deployable modular thin-shell structure for on-orbit assembly according to claim 2, characterized in that, 10:1； 。 4. The deployable modular thin-shell structure for on-orbit assembly according to claim 1, characterized in that, The side of the rotating shaft has two arc surfaces of unequal diameters, and two threaded holes are symmetrically opened on one arc surface. The fixing cover presses one end of the carbon fiber shell tightly with bolts. The diameter of the arc on the side of the rotating shaft is selected to be optimal by comparing the stability of the carbon fiber shell during the rolling process.

5. The deployable modular thin-shell structure for on-orbit assembly according to claim 1, characterized in that, The limiting cover is U-shaped when viewed from the side, with its four bottom corners connected to the motor base. The limiting cover and the corresponding parts of the upper shell are provided with openings for the carbon fiber thin shell to extend out.

6. The deployable modular thin-shell structure for on-orbit assembly according to claim 1 or 5, characterized in that, The carbon fiber shell, in its naturally stretched state, is an arc-shaped rod-shaped shell with a central angle of 120 degrees and a thickness of 0.2 mm.

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