A spatially deployable unit and a large-scale deployable platform

Abstract

The present invention discloses a space deployable unit and a large-scale deployable platform. The space deployable unit is a symmetrical multi-closed loop mechanism, including a first platform, a second platform, and a plurality of planar 4R branches connected to the first platform and the second platform; the planar 4R branch has a first connecting rod, a second connecting rod and a third connecting rod, one end of the first connecting rod is connected to the first platform through a first hinge point, the other end of the first connecting rod is connected to the second connecting rod through a second hinge point, one end of the third connecting rod is hinged to the second connecting rod through a third hinge point, and the other end of the third connecting rod is connected to the second platform through a fourth hinge point; wherein the rotation axes of the revolving pairs formed at the first hinge point, the second hinge point, the third hinge point and the fourth hinge point are parallel to each other; the second connecting rods in adjacent planar 4R branches are connected by two symmetrically distributed planar 3R branches. The present invention has the advantages of good symmetry, high rigidity, light weight, structural stability and high reliability.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace, and in particular relates to a space deployable unit and a large-scale deployable platform. Background Art

[0002] It is of great significance to build a large multifunctional on-orbit service station for three-dimensional space services to carry out on-orbit upgrades, faulty module replacement, replenishment, assembly and other maintenance tasks for service satellites; and the on-orbit service station is inseparable from the support and fixation of large-scale deployable aerospace platforms. Large-scale space operation platforms are composed of multi-module deployable mechanism units connected by networking, and need to have high rigidity, large load, light weight, high storage ratio, high precision and other performance.

[0003] The deployable mechanisms proposed at home and abroad are mainly used for articulated extension arms, solid reflector type deployable antennas, frame type deployable antennas, ring truss type deployable antennas, etc. The above structures are difficult to be directly applied to large-scale on-orbit service space stations and cannot meet the mission requirements of large-scale deployable aerospace platforms; for example, the hinged extension arm has high structural strength and rigidity, and high repeated deployment accuracy, but the storage ratio is relatively small and the weight is large; the solid reflector type deployable antenna has a large storage rate and high structural rigidity, but the structure of the antenna is complex and the weight is large, which is not suitable for large-scale; the space frame type deployable antenna has the advantages of high storage ratio, high precision, good deployment stability, good thermal stability, and spatial splicing, but the support system is complex, the structural mass is large, and it is also difficult to large-scale; the advantages of the ring truss type deployable antenna are high storage rate and small mass, but due to the large number of vertical cables and complex structure, the rigidity of the ring truss decreases significantly after the caliber increases, and the shape and surface accuracy is not easy to control.

[0004] In the future large-scale multifunctional on-orbit service stations, the large-scale deployable aerospace platform needs to be deployed to provide support and fixation for other service satellites to be maintained. Designing a large-scale deployable aerospace platform with large load, high stiffness, large storage ratio, light weight and high precision is an important part of seizing the future space on-orbit service system. In addition, most of the existing deployable mechanisms are large-scale deployable mechanisms based on over-constrained single-ring mechanisms or multi-ring mechanism module unit networking. Due to the existence of over-constraints, the entire mechanism cannot be deployed after large-scale networking; at the same time, due to the need to ensure the strict geometric relationship of the mechanism and the complexity of the constraints, it also brings difficulties to the processing, manufacturing and assembly of the mechanism. Summary of the invention

[0005] The main purpose of the present invention is to provide a spatially deployable unit and a large-scale deployable platform to overcome many deficiencies in the prior art.

[0006] In order to achieve the above main purpose, the first aspect of the present invention is to provide a spatially deployable unit, which is a symmetrical multi-closed-loop mechanism, comprising a first platform, a second platform, and a plurality of planar 4R branches connected to the first platform and the second platform;

[0007] The planar 4R branch chain comprises a first link, a second link and a third link, one end of the first link is connected to the first platform via a first hinge point, the other end of the first link is connected to the second link via a second hinge point, one end of the third link is hinged to the second link via a third hinge point, and the other end of the third link is connected to the second platform via a fourth hinge point; wherein the rotation axes of the rotation pairs formed at the first hinge point, the second hinge point, the third hinge point and the fourth hinge point are parallel to each other;

[0008] The second links in the adjacent plane 4R branches are connected through two symmetrically distributed plane 3R branches; wherein the plane 3R branch has a fourth link and a fifth link, the fourth link and the fifth link are connected to the second link in the adjacent plane 4R branch through a fifth hinge point and a sixth hinge point respectively, and the fourth link and the fifth link are connected to each other through a seventh hinge point; wherein the rotation axes of the rotation pairs formed at the fifth hinge point, the sixth hinge point and the seventh hinge point are parallel to each other;

[0009] When the first platform and the second platform approach each other, the first link and the third link in the plane 4R branch chain are folded towards each other, and the fourth link and the fifth link in the plane 3R branch chain are unfolded back to back; when the first platform and the second platform are separated back to back, the first link and the third link in the plane 4R branch chain are unfolded back to back, and the fourth link and the fifth link in the plane 3R branch chain are folded towards each other.

[0010] According to an implementation manner of the present invention, the spatially expandable unit further includes a central branch chain, and the central branch chain is a retractable branch chain.

[0011] Furthermore, the central branch chain includes a sixth connecting rod and a seventh connecting rod, and the sixth connecting rod and the seventh connecting rod are connected through a moving pair.

[0012] According to an implementation mode of the present invention, the spatially expandable unit is in a cubic structure, and the first platform and the second platform form two opposite side surfaces of the cubic structure; the number of planar 4R branches is four, and the planar 4R branches are respectively connected to corresponding corners of the first platform and the second platform.

[0013] Furthermore, the second hinge point and the third hinge point are close to the middle of the second connecting rod, and the fifth hinge point and the sixth hinge point are close to the end of the second connecting rod.

[0014] According to an embodiment of the present invention, the first connecting rod and the third connecting rod have the same length, and the fourth connecting rod and the fifth connecting rod have the same length.

[0015] The second aspect of the present invention is to provide a large-scale deployable platform formed by networking a plurality of the spatially deployable units as described above.

[0016] According to an embodiment of the present invention, the second connecting rods of the planar 4R branches in adjacent spatially deployable units are connected as one piece or prefabricated as one piece.

[0017] According to an embodiment of the present invention, the large-scale deployable platform includes a driving unit, and the driving unit is used to drive a first platform and a second platform in at least one spatially deployable unit to move toward each other or to move away from each other.

[0018] The present invention has the following beneficial effects:

[0019] The present invention has the advantages of good symmetry, high rigidity, light weight, structural stability and high reliability, and can provide support, positioning and fixation for satellites to be serviced in large space service stations.

[0020] In the spatially deployable unit of the present invention, a planar branch chain composed of a rotation pair parallel to the rotation axis is used as the basic cell, which has excellent foldability and single degree of freedom characteristics. Compared with a spatially over-constrained deployable single-ring mechanism, the present invention will not get stuck, and the driving system is simple, thus being easier to be applied in practice.

[0021] In order to more clearly illustrate the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is an overall structural diagram of a spatially expandable unit in Embodiment 1 of the present invention;

[0023] Figure 2 It is a partial structural diagram of a spatially expandable unit in Embodiment 1 of the present invention;

[0024] Figure 3 is a schematic diagram of a folded state of the large-scale deployable platform in Example 1 of the present invention;

[0025] Figure 4 Schematic diagram of the unfolded state of the large-scale unfoldable platform in Example 1 of the present invention;

[0026] Figure 5 is a schematic diagram of an internal connector in Example 1 of the present invention;

[0027] Figure 6 It is a schematic diagram of the external connecting parts in Example 1 of the present invention. DETAILED DESCRIPTION

[0028] Example 1

[0029] like Figure 1 As shown, embodiment 1 provides a spatially deployable unit 10 having a symmetrical multi-closed-loop mechanism; the spatially deployable unit 10 is a cubic structure, which includes a first platform 11, a second platform 12, four planar 4R branches 13, four planar 3R branches 14 and a central branch 15; wherein the first platform 11 and the second platform 12 form two opposite sides of the cubic structure, specifically Figure 1 The upper top surface and the lower bottom surface of the cube structure are connected to the corresponding corners of the first platform 11 and the second platform 12, and the plane 3R branch chain 14 is formed on the four continuous circumferential sides of the cube structure. Figure 1 The front side, back side, left side and right side of the body.

[0030] like Figure 2 As shown, the plane 4R branch chain 13 has a first link 131, a second link 132 and a third link 133, wherein the lengths of the first link 131 and the third link 133 are equal;

[0031] One end of the first connecting rod 131 passes through the first hinge point O 1 Connected to the first platform 11, the other end of the first connecting rod 131 is connected to the first platform 11 through the second hinge point O 2 The third connecting rod 133 is connected to the second connecting rod 132, and one end of the third connecting rod 133 is connected to the second connecting rod 132 through the third hinge point O 3 The other end of the third connecting rod 133 is hinged to the second connecting rod 132, and the other end of the third connecting rod 133 is connected to the second connecting rod 132 through the fourth hinge point O 4 Connected to the second platform 12; wherein the first hinge point O 1 , the second hinge point O 2 , the third hinge point O 3 and the fourth hinge point O 4 The rotation axes of the rotating pairs formed at the locations are parallel to each other.

[0032] In order to achieve large-scale networking and synchronous driving, the second connecting rods 132 in adjacent plane 4R branches 13 are connected by two plane 3R branches 14 symmetrically distributed up and down; Figure 2 As shown, the planar 3R branch chain 14 has a fourth link 141 and a fifth link 142 of equal length;

[0033] The fourth link 141 and the fifth link 142 are respectively connected through the fifth hinge point O 5 , the sixth hinge point O 6 The second link 132, the fourth link 141 and the fifth link 142 in the adjacent plane 4R branch chain 13 are connected through the seventh hinge point O 7 interconnected; wherein the fifth hinge point O 5 , the sixth hinge point O6 and the seventh hinge point O 7 The rotation axes of the rotating pairs formed at the locations are parallel to each other.

[0034] Furthermore, the second hinge point O 2 , the third hinge point O 3 Near the middle of the second connecting rod 132, the fifth hinge point O 5 and the sixth hinge point O 6 The end portion close to the second connecting rod 132 is designed to eliminate interference that may occur during the folding and unfolding process, thereby improving the smoothness of the overall structure.

[0035] The central branch chain 15 is a retractable branch chain to provide guidance for the movement of the first platform 11 and the second platform 12 so that the two can move in a straight line; the central branch chain 15 includes a sixth link 151 and a seventh link 152, and the sixth link 151 and the seventh link 152 are connected by a moving pair P; a driving unit is set at the central branch chain 15 to drive the first link 131 and the seventh link 152 to form relative sliding, and the driving unit is, for example, an electric cylinder driver to form an electric cylinder driven moving pair at the moving pair, thereby driving the first platform 11 and the second platform 12 to approach each other or unfold back to back.

[0036] Specifically, in this embodiment, when the first platform 11 and the second platform 12 approach each other, the first link 131 and the third link 133 in the plane 4R branch chain 13 are folded toward each other, and the fourth link 141 and the fifth link 142 in the plane 3R branch chain 14 are unfolded toward each other; when the first platform 11 and the second platform 12 are separated toward each other, the first link 131 and the third link 133 in the plane 4R branch chain 13 are unfolded toward each other, and the fourth link 141 and the fifth link 142 in the plane 3R branch chain 14 are folded toward each other.

[0037] In this embodiment, the first hinge point O 1 , the second hinge point O 2 , the third hinge point O 3 and the fourth hinge point O 4 The rotation axes of the rotation pair formed at the position are parallel to each other, and the fifth hinge point O 5 , the sixth hinge point O 6 and the seventh hinge point O 7 The rotation axes of the rotating pairs formed at the locations are parallel to each other, that is, each branch chain adopts a parallel rotating pair. Therefore, the multi-closed-loop mechanism of this embodiment provides a couple constraint; compared with the branch chain structure that provides force constraint, based on the fact that the couple is an even quantity, the branch chain that provides the couple constraint does not need to strictly guarantee the position and direction of the force axis like the force constraint, which is conducive to processing, manufacturing and assembly, thereby indirectly improving the deployability of the entire mechanism; the entire mechanism is a multi-closed-loop mechanism, which improves the overall stiffness and load capacity of the unit.

[0038] like Figure 3-4 As shown, Example 1 also provides a large-scale expandable platform 20 formed by networking the above-mentioned space expandable units 10. The large-scale expandable platform 20 occupies a smaller space when folded and occupies a larger space when expanded, so as to provide support, positioning and fixation for the satellite to be served.

[0039] The second connecting rods 132 of the planar 4R branches 13 in the adjacent spatially deployable units 10 are connected as a whole or prefabricated as a whole; in order to achieve better networking connection, in this embodiment, the adjacent second connecting rods 132 form two types of connecting members, namely, Figure 5 The internal connector 21 and Figure 6 The external connector 22 shown makes the network connection more compact, reduces the difficulty of processing, manufacturing and assembly, and makes the large-scale deployable platform 20 formed by the network easier to fold and unfold.

[0040] In this embodiment, each space-deployable unit 10 itself is a completely symmetrical mechanism, and the moving pair P at the central branch chain 15 is a driving pair. At the same time, the driving pair is arranged at the center of the space-deployable unit 10, which is conducive to improving the uniformity of the driving force transmitted by the entire unit; when networking, each space-deployable unit 10 is a single-degree-of-freedom deployment movement. After networking, the control of the large-scale deployable platform 20 is very simple. It is preferred to set a driving unit on the space-deployable unit 10 at the center of the large-scale deployable platform 20, so that each space-deployable unit 10 is evenly stressed, so that the deployment process is more stable and reliable. Correspondingly, the moving platform (first plane or second platform 12) on each space-deployable unit 10 is provided with corresponding structures such as holes and grooves to provide support, positioning and fixation for the satellite to be serviced.

[0041] Although the present invention is disclosed as above with specific embodiments, these specific embodiments are not intended to limit the scope of the present invention. Any person skilled in the art may make some changes / modifications without departing from the scope of the present invention, that is, any equivalent changes / modifications made according to the present invention should be covered by the protection scope of the present invention.

Claims

1. A spatially expandable unit, Features: The spatially deployable unit is a symmetrical multi-closed-loop mechanism, which includes a first platform, a second platform, and a plurality of planar 4R branches connected to the first platform and the second platform; The planar 4R branch chain comprises a first link, a second link and a third link, one end of the first link is connected to the first platform via a first hinge point, the other end of the first link is connected to the second link via a second hinge point, one end of the third link is hinged to the second link via a third hinge point, and the other end of the third link is connected to the second platform via a fourth hinge point; wherein the rotation axes of the rotation pairs formed at the first hinge point, the second hinge point, the third hinge point and the fourth hinge point are parallel to each other; The second links in the adjacent plane 4R branches are connected through two symmetrically distributed plane 3R branches; wherein the plane 3R branch has a fourth link and a fifth link, the fourth link and the fifth link are connected to the second links in the adjacent plane 4R branches through a fifth hinge point and a sixth hinge point respectively, and the fourth link and the fifth link are connected to each other through a seventh hinge point; wherein the rotation axes of the rotation pairs formed at the fifth hinge point, the sixth hinge point and the seventh hinge point are parallel to each other; When the first platform and the second platform are approaching each other, the first link and the third link in the plane 4R branch chain are folded toward each other, and the fourth link and the fifth link in the plane 3R branch chain are unfolded away from each other; when the first platform and the second platform are separated away from each other, the first link and the third link in the plane 4R branch chain are unfolded away from each other, and the fourth link and the fifth link in the plane 3R branch chain are folded toward each other.

2. The spatially deployable unit according to claim 1, Features: The spatially expandable unit further comprises a central branch chain, and the central branch chain is a retractable branch chain.

3. The spatially deployable unit according to claim 2, Features: The central branch chain includes a sixth connecting rod and a seventh connecting rod, and the sixth connecting rod and the seventh connecting rod are connected through a moving pair.

4. The spatially deployable unit according to claim 1, Features: The spatially expandable unit is in a cubic structure, and the first platform and the second platform form two opposite sides of the cubic structure; the number of the planar 4R branches is four, and the planar 4R branches are respectively connected to the corresponding corners of the first platform and the second platform.

5. The spatially deployable unit according to claim 4, Features: The second hinge point and the third hinge point are close to the middle of the second connecting rod, and the fifth hinge point and the sixth hinge point are close to the end of the second connecting rod.

6. The spatially deployable unit according to claim 1, Features: The first connecting rod and the third connecting rod have the same length, and the fourth connecting rod and the fifth connecting rod have the same length.

7. A large-scale deployable platform formed by networking and connecting a plurality of spatially deployable units as described in any one of claims 1 to 6.

8. The large-scale deployable platform according to claim 7, Features: The second connecting rods of the planar 4R branches in adjacent spatially expandable units are connected as one or prefabricated as one.

9. The large-scale deployable platform according to claim 7, Features: The large-scale deployable platform comprises a driving unit, and the driving unit is used to drive the first platform and the second platform in at least one of the spatially deployable units to move toward each other or away from each other.

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