Linked double-ring truss deployable antenna mechanism based on trapezoidal composite unit

Abstract

The invention provides a linkage type double ring truss deployable antenna mechanism based on a trapezoidal composite unit, which comprises N folding units A with the same structure, N being an integer greater than or equal to 3, adjacent folding units A being connected to each other by sharing two inner faceplates and two outer faceplates, the folding units A comprising folding units B, folding units C and connecting rods, the folding units B being connected by the folding units C and the connecting rods, the rotation sub-axes of the connecting rods in the folding units C being parallel, and the deployable antenna mechanism being a multi-faceted ring truss after being deployed or folded; the folding units A can be arbitrarily changed according to the requirements of the caliber of the deployable antenna, wherein the synchronization rod and the connecting rod are adjusted according to the caliber and the folding ratio of the deployable antenna, thereby solving the problems of complex structure, heavy weight and poor rigidity strength of the existing deployable antenna, having the advantages of good manufacturing process type, high rigidity and large folding ratio, and being preferably applied to large-caliber satellite-borne antennas, communication satellites and space probes.

Description

Technical Field

[0001] The invention relates to the technical field of foldable antenna mechanisms, and in particular to a linked double-ring truss deployable antenna mechanism based on a trapezoidal composite unit. Background Art

[0002] With the continuous development of the aerospace industry, the size of the space mechanisms required in various aerospace projects is getting larger and larger to meet the needs of different aerospace missions. The application of large-aperture space antennas can greatly improve the resolution level of earth observation, satellite communication distance and data transmission and reception capacity, space power generation capacity, space reconnaissance and precision strike capabilities, etc. Its development has always been highly valued by countries around the world. An important application of large-scale space folding mechanisms in the aerospace field is as a deployment and support mechanism for large-aperture antennas. The large-aperture space deployable antennas that have been successfully developed include frame type, peripheral grid type, radial rib type and folded rib type. These antenna mechanisms have their own characteristics and play an important role in space communication and data transmission.

[0003] The ring-shaped truss deployable antenna has the characteristics of large folding ratio, small mass, and mass that does not increase proportionally with the increase of diameter. It is an ideal structural form for large-diameter deployable antennas of tens to hundreds of meters in space. Relevant scientific researchers in various countries have conducted in-depth research on it and achieved on-orbit application. However, there are few types of existing ring-shaped truss mechanisms, and there is a serious problem that the antenna stiffness decreases with the increase of the antenna diameter. Some ring-shaped truss deployable antennas use tensioning zippers to improve the overall stiffness of the antenna mechanism, but the tensioning zippers are relatively complex and difficult to control, which also reduces the reliability of the overall structure. It is very easy to get entangled during the deployment process, causing the ring-shaped truss antenna to fail to deploy. Therefore, it is urgent to propose a deployable antenna mechanism with good manufacturing processability, high stiffness, large folding ratio and other excellent performance to meet the needs of different space missions. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a linked double-ring truss deployable antenna mechanism based on a trapezoidal composite unit, wherein the folding unit B can be arbitrarily changed according to the requirements of the caliber of the deployable antenna, and its synchronization rod and connecting rod are adjusted according to the caliber and folding ratio of the deployable antenna, thereby solving the problems of complex structure, heavy weight and poor rigidity and strength of the existing deployable antenna, and having the advantages of good manufacturing process, high rigidity and large folding ratio, and being preferably applied to large-caliber satellite-borne antennas, communication satellites and space probes.

[0005] The present invention provides a linkage type double ring truss deployable antenna mechanism based on a trapezoidal composite unit, which comprises N folding units A with the same structure, N being an integer greater than or equal to 3, adjacent folding units A being connected to each other by sharing two inner faceplates and two outer faceplates, and the deployable antenna mechanism is a multi-faceted annular truss after being unfolded or folded, the folding unit A comprising a folding unit B, a folding unit C and a connecting rod, the folding units B being connected by the folding unit C and the connecting rod, and the two ends of the connecting rod being respectively fixedly connected to the inner faceplate in the folding unit B; the folding unit B comprising an inner faceplate, a first synchronization rod, a web rod, a center faceplate, a second synchronization rod, a third synchronization rod and The outer flower disc, the adjacent inner flower discs are connected by the first synchronization rod, the central flower disc is connected to the inner flower disc and the outer flower disc respectively through the belly rod, the inner flower disc is connected to the outer flower disc through the second synchronization rod, and the adjacent outer flower discs are connected by the third synchronization rod; the folding unit C includes a first connecting rod, a second connecting rod, a third connecting rod and a fourth connecting rod, the first end of the first connecting rod is connected to the outer flower disc, the second end of the first connecting rod is connected to the first end of the second connecting rod, the second end of the second connecting rod is respectively connected to the first end of the third connecting rod and the fourth connecting rod, the middle intersection of the adjacent third connecting rods is connected by a rotating pair, and the adjacent fourth connecting rods are connected by a rotating pair.

[0006] Preferably, the two inner flower discs and the two outer flower discs are arranged in an isosceles trapezoid on the projection plane, the adjacent inner flower discs are connected by two first synchronization rods, the first synchronization rods are rotatably connected to form the upper base of the trapezoid, the adjacent outer flower discs are connected by two third synchronization rods, the third synchronization rods are rotatably connected to form the lower base of the trapezoid, the inner flower discs and the outer flower discs are connected by two second synchronization rods, the second synchronization rods are rotatably connected to form the waist of the trapezoid.

[0007] Preferably, the inner faceplate is located on the inner ring truss, and the inner faceplate is a double-layer symmetrical structure, the first layer of the inner faceplate is provided with three double-notch forks, and the notches are provided with through holes, and the overall structure is symmetrical with the middle fork notch symmetry plane, the inner faceplate is symmetrically provided with side forks on both sides, the middle fork is used to insert the end of the second synchronization rod and is connected through a rotating pair, the side fork is used to insert the end of the first synchronization rod and is connected through a rotating pair, the angle between the side fork symmetry plane and the middle fork symmetry plane is (180-360 / N)°, the second layer of the inner faceplate is provided with two double-notch forks, the angle between the two fork notch symmetry planes is [90-45(N-2) / N]°, and both forks are used to insert the first end of the web rod and be connected to the center faceplate through a rotating pair.

[0008] Preferably, the center faceplate is a plane-symmetrical structure, and four double-notch forks are provided on the center faceplate, and two forks are symmetrically provided on both sides of the middle symmetry plane, which are respectively used to insert the ends of the webs and are connected through a revolute pair, and the angle between the two fork notch symmetry planes close to the middle symmetry plane is 70°, and the angle between the two fork notch symmetry planes located on one side of the middle symmetry plane is 75°.

[0009] Preferably, the outer faceplate is located on the outer ring truss, and the outer faceplate is a double-layer symmetrical structure, the first layer of the outer faceplate is provided with three double-notch forks, and the overall structure is symmetrical with the middle fork notch symmetry plane, the middle fork is used to insert the end of the second synchronization rod and is connected through a rotating pair, the side fork is used to insert the end of the third synchronization rod and is connected through a rotating pair, the angle between the side fork of the outer faceplate and the middle symmetry plane is 75°, the second layer of the outer faceplate is provided with two double-notch forks, the angle between each fork notch symmetry plane and the middle symmetry plane of the outer faceplate is 55°, and both forks are used to insert the first end of the web rod and are connected to the center faceplate through a rotating pair.

[0010] Preferably, the first synchronization rod, the second synchronization rod, the third synchronization rod, the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod and the connecting rod in the folding unit A should all satisfy a specific proportional relationship, and the size of each rod is reasonably adjusted according to the angle between the branches on the inner flower disc, the center flower disc and the outer flower disc.

[0011] Preferably, the folding unit C is a highly symmetrical structure and is located on the outer ring truss of the deployable antenna mechanism, the rotation secondary axes of each connecting rod in the folding unit C are parallel, and when the folding unit B is fully unfolded, the adjacent fourth connecting rods are collinear, the folding unit C is in a singular position, the plane where the outer flower disc is located is higher than the plane where the inner flower disc is located, and the deployable antenna mechanism is unfolded into a double ring structure.

[0012] Preferably, the full deployment and folding of the deployable antenna mechanism is achieved by adjusting the angles between the synchronization rods and the connecting rods in the folding unit B and the folding unit C. When the deployable antenna mechanism is in the folded state, the distance between the inner flower disc and the center flower disc gradually increases, and the volume of the folding unit A is reduced. When the deployable antenna mechanism is in the fully folded state, the synchronization rods and the connecting rods are close to each other, the plane where the outer flower disc is located is at the same height as the plane where the inner flower disc is located, and the deployable antenna mechanism is in the minimum volume state, and the whole is contracted into a cylindrical structure.

[0013] Preferably, each synchronization rod and connecting rod in the folding and unfolding unit A is made of carbon fiber composite material or aviation aluminum alloy material.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. The present invention changes the size of the aperture of the deployable antenna mechanism after it is fully deployed by changing the number of folding and unfolding units A in the mechanism and the length of the synchronization rod and the connecting rod therein. When the folding rod is fully deployed, the entire mechanism reaches a fully deployed state. At this time, it is in a boundary singular configuration state, and the mechanism degenerates into a structure with zero degree of freedom. The rods in the structure can offset the effects of external forces by themselves without providing additional driving torque. The entire mechanism has good structural stiffness and mechanical properties.

[0016] 2. The present invention has a high degree of structural symmetry, and the kinematic pairs contained therein are all rotational pairs, which is conducive to improving the adaptability of the deployable antenna mechanism to the growing demand in space research, fully meeting the use requirements of large-caliber deployable antennas, and making the space deployable antenna mechanism safer, more efficient and convenient during operation.

[0017] 3. The folding unit B of the present invention can be changed arbitrarily according to the requirements of the diameter of the deployable antenna. Its synchronization rod and connecting rod are adjusted according to the diameter and folding ratio of the deployable antenna, which solves the problems of complex structure, heavy weight and poor rigidity and strength of the existing deployable antenna. It has the advantages of good manufacturing process, high rigidity and large folding ratio, and is preferably used in large-diameter satellite antennas, communication satellites and space probes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention when it is fully developed;

[0019] Figure 2 It is a schematic diagram of the semi-folded overall structure of the present invention;

[0020] Figure 3 It is a schematic diagram of the overall structure of the present invention when it is fully folded;

[0021] Figure 4 This is a schematic diagram of the overall structure of the folding and unfolding unit A of the present invention when it is fully unfolded;

[0022] Figure 5 It is a schematic diagram of the overall structure of the folding and unfolding unit A of the present invention when it is half folded;

[0023] Figure 6 This is a schematic diagram of the overall structure of the folding and unfolding unit A of the present invention when it is completely folded;

[0024] Figure 7 This is a schematic diagram of the overall structure of the folding and unfolding unit B of the present invention when it is fully unfolded;

[0025] Figure 8 It is a schematic diagram of the overall structure of the folding and unfolding unit B of the present invention when it is half folded;

[0026] Fig. 9This is a schematic diagram of the overall structure of the folding and unfolding unit B of the present invention when it is completely folded;

[0027] Fig.10 This is a schematic diagram of the overall structure of the folding and unfolding unit C of the present invention when it is fully unfolded;

[0028] Fig.11 It is a schematic diagram of the overall structure of the folding and unfolding unit C of the present invention when it is half folded;

[0029] Fig.12 It is a schematic diagram of the structure of the inner faceplate of the present invention;

[0030] Fig.13 This is a schematic diagram of the central faceplate structure of the present invention;

[0031] Fig.14 It is a schematic diagram of the structure of the outer faceplate of the present invention.

[0032] Main reference numerals:

[0033] Folding and unfolding unit A, folding and unfolding unit B, inner faceplate 11, first synchronization rod 12, belly rod 13, central faceplate 14, second synchronization rod 15, third synchronization rod 16, outer faceplate 17, folding and unfolding unit C, first connecting rod 21, second connecting rod 22, third connecting rod 23, fourth connecting rod 24, connecting rod 3. DETAILED DESCRIPTION

[0034] In order to fully describe the technical content, structural features, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0035] The invention provides a linked double-ring truss deployable antenna mechanism based on a trapezoidal composite unit, such as Figures 1 to 6As shown, it includes N foldable units A with the same structure, N is an integer greater than or equal to 3, adjacent foldable units A are connected to each other by sharing two inner discs 11 and two outer discs 17, and the deployable antenna mechanism is a multi-faceted annular truss after being deployed or folded. The foldable unit A includes a foldable unit B, a foldable unit C and a connecting rod 3, and the foldable units B are connected by the foldable unit C and the connecting rod 3, and the two ends of the connecting rod 3 are respectively fixedly connected to the inner disc 11 in the foldable unit B; the foldable unit B includes The inner faceplate 11, the first synchronization rod 12, the web rod 13, the central faceplate 14, the second synchronization rod 15, the third synchronization rod 16 and the outer faceplate 17, the inner faceplate 11 is located on the inner ring truss, the adjacent inner faceplates 11 are connected by the first synchronization rod 12, the central faceplate 14 is connected to the inner faceplate 11 and the outer faceplate 17 by the web rod 13 respectively, the inner faceplate 11 is connected to the outer faceplate 17 by the second synchronization rod 15, the outer faceplate 17 is located on the outer ring truss, and the adjacent outer faceplates 17 are connected by the third synchronization rod 16. The fully unfolding and folding of the deployable antenna mechanism is achieved by adjusting the angles between the synchronization rods and the connecting rods in the folding and unfolding units B and C. When the deployable antenna mechanism is in the folded state, the distance between the inner faceplate 11 and the central faceplate 14 gradually increases, and the volume of the folding and unfolding unit A is reduced. When the deployable antenna mechanism is in the fully folded state, the synchronization rods and the connecting rods are close to each other, and the plane where the outer faceplate 17 is located is at the same height as the plane where the inner faceplate 11 is located. The deployable antenna mechanism is in the minimum volume state and the whole is contracted into a cylindrical structure. The first synchronization rod 12, the second synchronization rod 15, the third synchronization rod 16, the first connecting rod 21, the second connecting rod 22, the third connecting rod 23, the fourth connecting rod 24 and the connecting rod 3 in the folding and unfolding unit A should all meet a specific proportional relationship. The size of each rod is reasonably adjusted according to the angle between the branches on the inner faceplate 11, the central faceplate 14 and the outer faceplate 17. The synchronization rods and connecting rods in the folding and unfolding unit A are all made of carbon fiber composite materials or aviation aluminum alloy materials.

[0036] like Figures 7 to 9 As shown, the two inner flower discs 11 and the two outer flower discs 17 are arranged in an isosceles trapezoid on the projection plane, the adjacent inner flower discs 11 are connected by two first synchronization rods 12, the first synchronization rods 12 are rotatably connected to form the upper base of the trapezoid, the adjacent outer flower discs 17 are connected by two third synchronization rods 16, the third synchronization rods 16 are rotatably connected to form the lower base of the trapezoid, the inner flower discs 11 and the outer flower discs 17 are connected by two second synchronization rods 15, the second synchronization rods 15 are rotatably connected to form the waist of the trapezoid.

[0037] like Fig.10 and Fig.11As shown, the folding unit C includes a first link 21, a second link 22, a third link 23 and a fourth link 24. The first end of the first link 21 is connected to the outer disc 17, the second end of the first link 21 is connected to the first end of the second link 22, the second end of the second link 22 is respectively connected to the first ends of the third link 23 and the fourth link 24, the middle intersection of adjacent third links 23 is connected by a revolute pair, and the adjacent fourth links 24 are connected by a revolute pair. The folding unit C is a highly symmetrical structure and is located on the outer ring truss of the deployable antenna mechanism. The revolute pair axes of each link in the folding unit C are parallel. When the folding unit B is fully deployed, the adjacent fourth links 24 are collinear, and the folding unit C is in a singular position to ensure the stability of the antenna mechanism. The plane where the outer disc 17 is located is higher than the plane where the inner disc 11 is located. The deployable antenna mechanism is deployed into a double ring structure, which effectively improves the folding ratio of the deployable antenna mechanism.

[0038] like Fig.12 As shown, the inner faceplate 11 is a double-layer symmetrical structure. The first layer of the inner faceplate 11 is provided with three double-slot forks, and through holes are opened on the slots. The overall structure is symmetrical with the middle fork slot symmetry plane. The inner faceplate 11 is symmetrically provided with side forks on both sides. The middle fork is used to insert the end of the second synchronization rod 15 and is connected through a rotating pair. The side fork is used to insert the end of the first synchronization rod 12 and is connected through a rotating pair. The angle between the side fork symmetry plane and the middle fork symmetry plane is (180-360 / N)°. The second layer of the inner faceplate 11 is provided with two double-slot forks. The angle between the two fork slot symmetry planes is [90-45(N-2) / N]°. Both forks are used to insert the first end of the belly rod 13 and are connected to the center faceplate 14 through a rotating pair.

[0039] like Fig.13 As shown, the center faceplate 14 is a surface-symmetrical structure, and four double-slot forks are provided on the center faceplate 14. Two forks are symmetrically provided on both sides of the middle symmetry plane, which are respectively used to insert the ends of the web 13 and are connected through a revolute pair. The angle between the symmetry planes of the two forks near the middle symmetry plane is 70°, and the angle between the symmetry planes of the two forks located on one side of the middle symmetry plane is 75°.

[0040] like Fig.14As shown, the outer faceplate 17 is a double-layer symmetrical structure. The first layer of the outer faceplate 17 is provided with three double-notch forks. The overall structure is symmetrical with the middle fork notch symmetry plane. The middle fork is used to insert the end of the second synchronization rod 15 and is connected through a rotating pair. The side fork is used to insert the end of the third synchronization rod 16 and is connected through a rotating pair. The angle between the side fork of the outer faceplate 17 and the middle symmetry plane is 75°. The second layer of the outer faceplate 17 is provided with two double-notch forks. The angle between the notch symmetry plane of each fork and the middle symmetry plane of the outer faceplate 17 is 55°. Both forks are used to insert the first end of the belly rod 13 and are connected to the center faceplate 14 through a rotating pair.

[0041] The following is a further description of a linkage type double ring truss deployable antenna mechanism based on a trapezoidal composite unit of the present invention in conjunction with an embodiment:

[0042] The present invention changes the size of the aperture of the double-ring truss deployable antenna mechanism after it is fully deployed by changing the number of folding and unfolding units A in the overall mechanism and the length of each rod therein. When the two synchronous rods connected by the revolute pair are collinear, the overall mechanism reaches a fully deployed state, at which time it is in a boundary singular configuration state, and the degree of freedom of the mechanism is zero. At the same time, each rod in the overall mechanism can offset its own external force without providing additional driving torque, and the overall mechanism has good structural rigidity and mechanical properties.

[0043] Example:

[0044] like Figures 1 to 4 As shown, the present invention provides a linkage double-ring truss deployable antenna mechanism based on a trapezoidal composite unit, which includes N folding units A with the same structure, N is an integer greater than or equal to 3, and adjacent folding units A are connected to each other by sharing two inner flower discs 11 and two outer flower discs 17. The deployable antenna mechanism is a multi-faceted annular truss after being unfolded or folded. The folding unit A includes a folding unit B, a folding unit C and a connecting rod 3. The folding units B are connected by the folding unit C and the connecting rod 3, and the two ends of the connecting rod 3 are respectively connected to the folding units. The inner faceplate 11 in B is fixedly connected; the folding and unfolding unit B comprises an inner faceplate 11, a first synchronization rod 12, a web rod 13, a central faceplate 14, a second synchronization rod 15, a third synchronization rod 16 and an outer faceplate 17, adjacent inner faceplates 11 are connected by the first synchronization rod 12, the central faceplate 14 is connected to the inner faceplate 11 and the outer faceplate 17 respectively by the web rod 13, the inner faceplate 11 is connected to the outer faceplate 17 by the second synchronization rod 15, and adjacent outer faceplates 17 are connected by the third synchronization rod 16, forming a double-ring truss expandable antenna mechanism as a whole.

[0045] The operation process of this embodiment is achieved as follows:

[0046] At the initial moment, the deployable antenna mechanism is stored in the payload compartment of the rocket when the rocket is launched, the antenna is in a retracted state, the folding unit A, the folding unit B and the folding unit C are in a folded state, the first synchronization rod 12, the belly rod 13, the second synchronization rod 15, the third synchronization rod 16, the first connecting rod 21, the second connecting rod 22, the third connecting rod 23, the fourth connecting rod 24 and the connecting rod 3 are all close to each other, and the overall mechanism is folded into a cylindrical structure, which effectively saves the rocket launch space.

[0047] When the antenna reaches the designated position and starts working, each synchronization rod and connecting rod rotates 90° from the original position along the direction of the connecting rotation sub-axis under the action of the driving force, and the adjacent synchronization rods form a straight line to achieve locking, maintaining the expanded state of the mechanism without shrinking, and becoming a supporting unit for the inner and outer ring trusses. During the expansion process, each synchronization rod and connecting rod opens to both sides, each web rod 12 opens outward, and each connecting rod in the folding unit C opens synchronously, and the distance between the inner faceplate 11, the outer faceplate 17 and the center faceplate 14 gradually decreases, thereby pushing the inner faceplate 11 and the outer faceplate 17 to move outward along the radial direction of the cylinder, and the expandable antenna mechanism is expanded from the cylindrical structure to a double-ring truss.

[0048] The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A linkage double-ring truss deployable antenna mechanism based on a trapezoidal composite unit, characterized in that: It comprises N folding and spreading units A with the same structure, where N is an integer greater than or equal to 3, and adjacent folding and spreading units A are connected to each other by sharing two inner faceplates and two outer faceplates. The folding and unfolding unit A comprises a folding and unfolding unit B, a folding and unfolding unit C and a connecting rod, wherein the folding and unfolding units B are connected via the folding and unfolding unit C and the connecting rod, and the two ends of the connecting rod are respectively fixedly connected to the inner faceplate in the folding and unfolding unit B; the folding and unfolding unit B comprises an inner faceplate, a first synchronization rod, a belly rod, a central faceplate, a second synchronization rod, a third synchronization rod and an outer faceplate, wherein adjacent inner faceplates are connected via the first synchronization rod, the central faceplate is respectively connected to the inner faceplate and the outer faceplate via the belly rod, the inner faceplate is connected to the outer faceplate via the second synchronization rod, and adjacent outer faceplates are connected via the third synchronization rod; the folding and unfolding unit C comprises a first connecting rod, a second connecting rod, a third connecting rod and a fourth connecting rod, wherein the first end of the first connecting rod is fixedly connected to the outer faceplate The bottom ends are connected, the second end of the first connecting rod is connected to the first end of the second connecting rod, the second end of the second connecting rod is connected to the first ends of the third connecting rod and the fourth connecting rod respectively, the middle intersections of the adjacent third connecting rods are connected by a rotating pair, and the adjacent fourth connecting rods are connected by a rotating pair. The folding unit C is a highly symmetrical structure and is located on the outer ring truss of the deployable antenna mechanism. The rotating pair axes of each connecting rod in the folding unit C are parallel. When the folding unit B is fully unfolded, the adjacent fourth connecting rods are collinear, and the folding unit C is in a singular position. The plane where the outer flower disc is located is higher than the plane where the inner flower disc is located. The deployable antenna mechanism is unfolded into a double ring structure, and the deployable antenna mechanism is a multi-faceted ring truss after being unfolded or folded; The two inner flower discs and the two outer flower discs are arranged in an isosceles trapezoid on the projection plane, the adjacent inner flower discs are connected by two first synchronization rods, the first synchronization rods are rotatably connected to form the upper base of the trapezoid, the adjacent outer flower discs are connected by two third synchronization rods, the third synchronization rods are rotatably connected to form the lower base of the trapezoid, the inner flower discs and the outer flower discs are connected by two second synchronization rods, the second synchronization rods are rotatably connected to form the waist of the trapezoid; The inner faceplate is located on the inner ring truss, and the inner faceplate is a double-layer symmetrical structure. The first layer of the inner faceplate is provided with three double-notch forks, and through holes are opened on the notches. The overall structure is symmetrical with the middle fork notch symmetry plane. The inner faceplate is symmetrically provided with side forks on both sides. The middle fork is used to insert the end of the second synchronization rod and is connected through a rotation pair. The side fork is used to insert the end of the first synchronization rod and is connected through a rotation pair. The angle between the side fork symmetry plane and the middle fork symmetry plane is (180-360 / N)°. The second layer of the inner faceplate is provided with two double-notch forks. The angle between the two fork notch symmetry planes is [90-45(N-2) / N]°. Both forks are used to insert the first end of the web rod and are connected to the center faceplate through a rotation pair. The central faceplate is a face-symmetrical structure, and is provided with four double-notched forks, with two forks symmetrically arranged on both sides of the middle symmetric plane, respectively used to insert the second end of the web and connected through a revolute pair, the angle between the symmetric planes of the two forks near the middle symmetric plane is 70°, and the angle between the symmetric planes of the two forks located on one side of the middle symmetric plane is 75°; The outer faceplate is located on the outer ring truss, and the outer faceplate is a double-layer symmetrical structure. The first layer of the outer faceplate is provided with three double-notch forks, and the overall structure is symmetrical with the middle fork notch symmetry plane. The middle fork is used to insert the end of the second synchronization rod and is connected through a rotating pair. The side fork is used to insert the end of the third synchronization rod and is connected through a rotating pair. The angle between the side fork of the outer faceplate and the middle symmetry plane is 75°. The second layer of the outer faceplate is provided with two double-notch forks, and the angle between each fork notch symmetry plane and the middle symmetry plane of the outer faceplate is 55°. Both forks are used to insert the first end of the web rod and are connected to the center faceplate through a rotating pair.

2. The linked double-ring truss deployable antenna mechanism based on trapezoidal composite units according to claim 1, characterized in that: The first synchronization rod, the second synchronization rod, the third synchronization rod, the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod and the connecting rod in the folding and unfolding unit A should all satisfy a specific proportional relationship, and the size of each rod is reasonably adjusted according to the angle between the branches on the inner disc, the center disc and the outer disc.

3. The linked double-ring truss deployable antenna mechanism based on trapezoidal composite units according to claim 1, characterized in that: The full expansion and folding of the deployable antenna mechanism is achieved by adjusting the angles between the synchronization rods and the connecting rods in the folding and unfolding units B and C. When the deployable antenna mechanism is in the folded state, the distance between the inner flower disc and the central flower disc gradually increases, and the volume of the folding and unfolding unit A is reduced. When the deployable antenna mechanism is in the fully folded state, the synchronization rods and the connecting rods are close to each other, the plane where the outer flower disc is located is at the same height as the plane where the inner flower disc is located, and the deployable antenna mechanism is in the minimum volume state, and the whole is shrunk into a cylindrical structure.

4. The linked double-ring truss deployable antenna mechanism based on trapezoidal composite units according to any one of claims 1 to 3, characterized in that: Each synchronous rod and connecting rod in the folding and unfolding unit A is made of carbon fiber composite material or aviation aluminum alloy material.

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