Single-degree-of-freedom double-ring truss deployable antenna mechanism based on composite tetrahedron element

Abstract

The present invention provides a single-degree-of-freedom double-ring truss deployable antenna mechanism based on composite tetrahedron units, which comprises N composite tetrahedron units, where N is a positive integer greater than or equal to 3. The composite tetrahedron units are connected through a common inner faceplate, a synchronization rod, a connecting rod, a prism and an outer faceplate. The composite tetrahedron unit comprises two tetrahedron units with the same structure, and each component in the tetrahedron unit is connected through a rotation pair. The composite tetrahedron units are arranged in different ways and connected in different ways to each other. The composite tetrahedron units can be arbitrarily changed according to the requirements of the aperture of the deployable antenna. The synchronization rod, the connecting rod and the prism are adjusted according to the aperture and the 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. The composite tetrahedron unit has the advantages of optimized manufacturing process, high rigidity and large folding ratio, and is preferably applied to large-aperture 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 single-degree-of-freedom double-ring truss deployable antenna mechanism based on a composite tetrahedron unit. Background Art

[0002] During the launch process, the space antenna must be folded in the launch vehicle fairing in a folded state, and then smoothly unfolded after being launched to the designated position. This requires the antenna mechanism to have a large folding and unfolding ratio, that is, a smaller envelope volume in the folded state and a larger envelope volume in the unfolded state. Space deployable antennas can be divided into truss-type foldable and unfoldable antennas, elastic deformation deployable antennas, solid surface deployable antennas, and inflatable deployable antennas according to the folding and unfolding methods. The truss-type foldable antenna mechanism is the most widely used type of unfolding mechanism. It is a mechanism during the unfolding process, and forms a truss structure after being fully unfolded. It has the characteristics of high structural rigidity and high spatial positioning accuracy. At the same time, this type of antenna has several identical or similar folding and unfolding mechanism units, and the overall folding and unfolding ratio is large, which is an ideal form of large-caliber satellite-borne antenna.

[0003] With the continuous improvement of technical requirements, the performance of space antennas is also constantly developing in the direction of long distance, large capacity, high gain and high resolution, which puts forward requirements for deployable antennas such as large aperture, high rigidity, high precision and large folding ratio. Peripheral truss deployable antennas have good performance advantages in the field of large-aperture and ultra-large-aperture deployable antennas in space. Relevant researchers from various countries have done a lot of research on the deployment mechanism, cable net forming and deployment control of peripheral truss deployable antennas. However, overall, there are still few types of peripheral truss deployable antenna mechanisms currently in orbit, and as the antenna aperture increases, the overall structural rigidity decreases more seriously. Therefore, it is urgent to propose a truss-type deployable antenna mechanism with excellent performance such as simple structure, high rigidity, large folding ratio and good manufacturing processability 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 single-degree-of-freedom double-ring truss deployable antenna mechanism based on composite tetrahedron units. By changing the number of composite tetrahedron units and the length of each rod, deployable antenna mechanisms of different calibers are formed. The overall structure is simple and is a single-degree-of-freedom mechanism. The deployable antenna mechanism can be deployed by adding a drive, which solves the problems of complex structure, heavy weight and poor stiffness strength of the existing deployable antenna, and is preferably applied to large-caliber satellite-borne antennas, communication satellites and space probes.

[0005] The present invention provides a single-degree-of-freedom double-ring truss deployable antenna mechanism based on a composite tetrahedron unit, which includes N composite tetrahedron units with the same structure, N is an integer greater than or equal to 3, the composite tetrahedron unit includes a tetrahedron unit and a prism, the tetrahedron unit is arranged in a face-symmetrical manner, and the tetrahedron units are connected by prisms, the tetrahedron unit includes an inner faceplate, a synchronization rod, a connecting rod, a Y-shaped faceplate, an outer faceplate and a T-shaped faceplate, adjacent inner faceplates are rotationally connected by synchronization rods, and a plurality of inner faceplates are equilateral or isosceles triangles. The Y-shaped faceplate is arranged above the center of the triangle, the inner faceplates are connected to the Y-shaped faceplates through connecting rods, the outer faceplates are connected end to end in sequence through synchronization rods, the outer faceplates are connected to the T-shaped faceplates through connecting rods, the outer faceplates are arranged in a face-symmetrical manner and connected through prisms, the connection methods of the composite tetrahedral units are different due to different arrangement methods, the composite tetrahedral units are connected through a common inner faceplate, synchronization rod, connecting rod, prism and outer faceplate, and the whole constitutes a double-ring truss deployable antenna mechanism.

[0006] Preferably, the inner faceplate is located on the inner annular surface, and both the inner faceplate and the outer faceplate are double-layer symmetrical structures, the first layer of the inner faceplate is provided with four double-notch forks, and the notches are provided with through holes for inserting the ends of the synchronization rods and connecting them through a revolute pair, two synchronization rods form a group, and the synchronization rods are connected through a revolute pair, two notches form a group, and the angle between the notches in the same group is the base angle of the isosceles or equilateral triangle on the bottom surface of the tetrahedron unit, the base angle is θ1=a°, and the vertex angle of the isosceles or equilateral triangle is θ2=(360°-(180°-3 60 / N)-2a)°, the second layer of the inner layer faceplate is provided with three double-notch forks for inserting the end of the connecting rod and connecting through a rotating pair, and the center lines of the three notches coincide with the bisectors of the angles between the four notches of the first layer, and the angles between the notches of the second layer are 1 / 2(a+(360-(180-360 / N)-2a)°, a groove is also provided on the first layer of the inner layer faceplate, the first end of the prism is fixedly connected to the groove on the inner layer faceplate, and the second end of the prism is fixedly connected to the groove provided on the inner layer faceplate which is symmetrically arranged on the surface.

[0007] Preferably, the outer layer faceplate is located on the outer annular surface, the first layer of the outer layer faceplate is provided with four double-notch forks, the outer layer faceplate divides the double-notch forks into two groups with the middle symmetry plane, the angle between the double-notch forks in the same group is θ3=1 / 2(180-(360-(180-360 / N)-2a)°, the angle between two adjacent groups of notches is the vertex angle of an isosceles or equilateral triangle is θ4=(180-2a)°, the second layer of the outer layer faceplate is provided with three notches, and the angle between the notches is 1 / 2((180-2a)+(360-(180-360 / N)-2a))°.

[0008] Preferably, the Y-shaped flower disc and the T-shaped flower disc are both provided with three double-slot forks, and the slots are both provided with through holes, and the Y-shaped flower disc and the T-shaped flower disc are both plane-symmetrical structures as a whole, the middle symmetry plane of the Y-shaped flower disc and the T-shaped flower disc coincide with the middle fork symmetry plane, there is a fork on each side of the middle symmetry plane, the angle between each side fork symmetry plane and the middle symmetry plane is θ5=2a°, and the angle between the symmetry planes of the side forks is θ6=360-4a°.

[0009] Preferably, the synchronization rod, connecting rod and prism in the tetrahedral unit should all satisfy a specific proportional relationship, and the sizes of the synchronization rod, connecting rod and prism are reasonably adjusted according to the angles between the branches on the inner face disc, Y-shaped face disc, outer face disc and T-shaped face disc.

[0010] Preferably, there are three arrangements of the composite tetrahedral units: arrangement one: the adjacent composite tetrahedral units A and composite tetrahedral units B, the cylindrical surface of the composite tetrahedral unit A faces the ring center, the cylindrical surface of the composite tetrahedral unit B faces the outside of the ring, all the cylindrical surfaces facing the ring center together constitute the inner ring surface, all the cylindrical surfaces facing the outside of the ring center together constitute the outer ring surface, and the adjacent composite tetrahedral units A and composite tetrahedral units B are connected by two shared inner faceplates, two outer faceplates, two prisms and four synchronization rods; arrangement two : The prisms of adjacent composite tetrahedral units A all face the center of the ring, that is, the cylindrical surfaces of the composite tetrahedral units A facing the center of the ring together constitute the inner ring surface, and the adjacent composite tetrahedral units A share two inner flower disks and one prism, which are connected by four synchronization rods; Arrangement method three: One of the edges of the composite tetrahedral units B faces the center of the ring, and the cylindrical surface opposite to the edge faces outside the ring, that is, all cylindrical surfaces facing outside the ring together constitute the outer ring surface, and the adjacent composite tetrahedral units B share a prism and two outer flower disks, which are connected by four synchronization rods.

[0011] Preferably, the semi-folding and fully folding of the deployable antenna mechanism are achieved by adjusting the synchronization rod, the connecting rod and the prism. When the deployable antenna mechanism is in the semi-folded state, the distance between the Y-shaped flower discs or the T-shaped flower discs gradually decreases, and the volume of the composite tetrahedron unit is reduced. When the deployable antenna mechanism is in the fully folded state, the planes where the inner flower disc and the outer flower disc are located remain horizontal, the synchronization rods and the connecting rods are close to each other and are in the minimum volume state, and the whole is contracted into a cylindrical structure.

[0012] Preferably, the synchronization rod, the connecting rod and the prism are all made of carbon fiber composite material or aviation aluminum alloy material.

[0013] Compared with the prior art, the present invention has the following advantages:

[0014] 1. The present invention forms deployable antenna mechanisms of different calibers by changing the number of inner and outer tetrahedral units and the length of each rod. The overall structure is simple and is a single-degree-of-freedom mechanism. The deployable antenna mechanism can be deployed by adding a drive, and is preferably used in large-caliber satellite antennas, communication satellites and space probes.

[0015] 2. The present invention has revolute pairs at the joints of the mechanisms, and the inner and outer tetrahedral units are composed of a triangular structure connected by multiple faceplates and connecting rods, which improves the rigidity of the entire foldable antenna mechanism after unfolding, effectively reduces the overall weight, has good assembly and manufacturing processability and reliability, and a large overall folding ratio, meeting the use requirements of large-caliber deployable antennas in space.

[0016] 3. The structure of the present invention is highly symmetrical, which is conducive to improving the adaptability of the deployable antenna mechanism to the growing demand in space research, making the space deployable antenna mechanism safer, more efficient and convenient during operation, and solving the problems of complex structure, heavy weight and poor rigidity and strength of existing deployable antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention when it is fully developed;

[0018] Figure 2a It is a schematic diagram of the semi-expanded overall structure of the present invention;

[0019] Figure 2b-Figure 2c It is a schematic diagram of the overall structure of Example 1 of this method;

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

[0021] Figure 4 It is a top view schematic diagram of the overall structure of the present invention;

[0022] Figure 5Schematic diagram of the overall structure of the composite tetrahedral unit A of the present invention;

[0023] Figure 6 Schematic diagram of the overall structure of the tetrahedral unit in the composite tetrahedral unit A of the present invention;

[0024] Figure 7 It is a schematic diagram of the overall structure of the composite tetrahedral unit B of the present invention;

[0025] Figure 8 Schematic diagram of the overall structure of the tetrahedral unit in the composite tetrahedral unit B of the present invention;

[0026] Fig. 9 It is a schematic diagram of the structure of the inner layer faceplate of the present invention;

[0027] Fig.10 It is a schematic diagram of the structure of the outer layer flower disc of the present invention;

[0028] Fig.11 It is a schematic diagram of the structure of a Y-shaped faceplate of the present invention;

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

[0030] Fig.13 It is a fully unfolded oblique view of the second arrangement mode of the composite tetrahedron unit of the present invention;

[0031] Fig.14 It is a fully unfolded top view of the second arrangement of the composite tetrahedral units of the present invention;

[0032] Fig.15 It is a fully unfolded oblique view of the third arrangement mode of the composite tetrahedron unit of the present invention;

[0033] Fig.16 It is a fully unfolded top view of the third arrangement of the composite tetrahedral units of the present invention.

[0034] Main reference numerals:

[0035] Composite tetrahedral unit A, tetrahedral unit 1, inner faceplate 11, synchronization rod 12, connecting rod 13, Y-shaped faceplate 14, prism 15, composite tetrahedral unit B, outer faceplate 21, T-shaped faceplate 22. DETAILED DESCRIPTION

[0036] 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.

[0037] The present invention provides a single-degree-of-freedom double-ring truss deployable antenna mechanism based on a composite tetrahedron unit, such as Figures 1 to 4As shown, it includes N composite tetrahedral units A with the same structure, N is an integer greater than or equal to 3, the composite tetrahedral unit A includes a tetrahedral unit 1 and a prism 15, the tetrahedral unit 1 is arranged in a plane-symmetrical manner, and the tetrahedral units 1 are connected by the prism 15, the tetrahedral unit 1 includes an inner faceplate 11, a synchronization rod 12, a connecting rod 13, a Y-shaped faceplate 14, an outer faceplate 21 and a T-shaped faceplate 22, adjacent inner faceplates 11 are rotationally connected by the synchronization rod 12, and the plurality of inner faceplates 11 are arranged in an equilateral or isosceles triangle, and the Y-shaped faceplate 14 is located above the center of the triangle, The inner faceplate 11 is connected to the Y-shaped faceplate 14 through the connecting rod 13, and the outer faceplate 21 is connected end to end through the synchronization rod 12. The outer faceplate 21 is connected to the T-shaped faceplate 22 through the connecting rod 13. The outer faceplate 21 is arranged in a plane-symmetrical manner and connected through the prism 15. The composite tetrahedron unit A and the composite tetrahedron unit B have different connection modes due to their different arrangement modes. The composite tetrahedron unit A is connected through the shared inner faceplate 11, synchronization rod 12, connection rod 13, prism 15 and outer faceplate 21, and the whole constitutes a double-ring truss deployable antenna mechanism. The synchronization rod 12, connection rod 13 and prism 15 in the tetrahedron unit 1 should all meet a specific proportional relationship, and the sizes of the synchronization rod 12, connection rod 13 and prism 15 are reasonably adjusted according to the angles between the branches on the inner faceplate 11, the Y-shaped faceplate 14, the outer faceplate 21 and the T-shaped faceplate 22.

[0038] Combination Figure 3 As shown, the synchronization rod 12, the connecting rod 13 and the prism 15 are all made of carbon fiber composite material or aviation aluminum alloy material. The semi-folding and fully folding of the deployable antenna mechanism are achieved by adjusting the synchronization rod 12, the connecting rod 13 and the prism 15. When the deployable antenna mechanism is in the semi-folded state, the distance between the Y-shaped faceplate 14 or the T-shaped faceplate 22 gradually decreases, and the volume of the composite tetrahedron unit A is reduced. When the deployable antenna mechanism is in the fully folded state, the plane where the inner faceplate 11 and the outer faceplate 21 are located remains horizontal, and each synchronization rod 12 and the connecting rod 13 are close to each other, in the minimum volume state, and the whole shrinks into a cylindrical structure.

[0039] like Figure 5 and Figure 6As shown, the inner faceplate 11 is located on the inner annular surface, and both the inner faceplate 11 and the outer faceplate 21 are double-layer symmetrical structures. The first layer of the inner faceplate 11 is provided with four double-notch forks, and the notches are provided with through holes for inserting the ends of the synchronization rods 12 and connecting them through a revolute pair. Two synchronization rods 12 form a group, and the synchronization rods 12 are connected through a revolute pair. Two notches form a group, and the angle between the notches in the same group is the base angle of the isosceles or equilateral triangle on the bottom surface of the tetrahedron unit 1, the base angle is θ1=a°, and the vertex angle of the isosceles or equilateral triangle is θ2=(360°-(180°-3 60 / N)-2a)°, the second layer of the inner layer faceplate 11 is provided with three double-notch forks for inserting the end of the connecting rod 13 and connecting through a rotating pair, and the center lines of the three notches coincide with the bisectors of the angles between the four notches of the first layer, and the angles between the notches of the second layer are 1 / 2(a+(360-(180-360 / N)-2a)°, and a groove is also provided on the first layer of the inner layer faceplate 11, and the first end of the prism 15 is fixedly connected to the groove on the inner layer faceplate 11, and the second end of the prism 15 is fixedly connected to the groove provided on the inner layer faceplate 11 which is symmetrically arranged on the surface.

[0040] like Figures 7 to 10 As shown, the outer layer faceplate 21 is located on the outer annular surface, the first layer of the outer layer faceplate 21 is provided with four double-notch forks, the outer layer faceplate 21 divides the double-notch forks into two groups with the middle symmetry plane, the angle between the double-notch forks in the same group is θ3=1 / 2(180-(360-(180-360 / N)-2a)°, the angle between two adjacent groups of notches is the vertex angle of an isosceles or equilateral triangle is θ4=(180-2a)°, the second layer of the outer layer faceplate 21 is provided with three notches, and the angle between the notches is 1 / 2((180-2a)+(360-(180-360 / N)-2a))°.

[0041] like Fig.11 and Fig.12 As shown, the Y-shaped flower disc 14 and the T-shaped flower disc 22 are both provided with three double-slot forks, and the slots are both provided with through holes. The Y-shaped flower disc 14 and the T-shaped flower disc 22 are both plane-symmetrical structures as a whole. The middle symmetry plane of the Y-shaped flower disc 14 and the T-shaped flower disc 22 coincides with the middle fork symmetry plane, and there is a fork on each side of the middle symmetry plane. The angle between each side fork symmetry plane and the middle symmetry plane is θ5=2a°, and the angle between the symmetry planes of the side forks is θ6=360-4a°.

[0042] like Figure 13 to Figure 16As shown, there are three arrangements of the composite tetrahedral units. Arrangement 1: adjacent composite tetrahedral units A and composite tetrahedral units B, the cylindrical surface of the composite tetrahedral unit A faces the ring center, the cylindrical surface of the composite tetrahedral unit B faces the outside of the ring, all the cylindrical surfaces facing the ring center together form the inner ring surface, and all the cylindrical surfaces facing the outside of the ring center together form the outer ring surface, and the adjacent composite tetrahedral units A and composite tetrahedral units B are connected by two shared inner layer faceplates 11, two outer layer faceplates 21, two prisms 15 and four synchronization rods 12; Arrangement 2: adjacent composite tetrahedral units A and composite tetrahedral units B are connected by two shared inner layer faceplates 11, two outer layer faceplates 21, two prisms 15 and four synchronization rods 12; Arrangement 3: adjacent composite tetrahedral units A and composite tetrahedral units B are connected by two shared inner layer faceplates 11, two outer layer faceplates 21, two prisms 15 and four synchronization rods 12; Arrangement 4: adjacent composite tetrahedral units A and composite tetrahedral units B are connected by two shared inner layer faceplates 11, two outer layer faceplates 21, two prisms 15 and four synchronization rods 12; Arrangement 5: adjacent composite tetrahedral units A and composite tetrahedral units B are connected by two shared inner layer faceplates 11, two outer layer faceplates 21, two prisms 15 and four synchronization rods 12; Arrangement 6: adjacent composite tetrahedral units A and composite tetrahedral units B are connected by two shared inner layer faceplates 11, two outer layer faceplates 21, two prisms 15 and four synchronization rods 12; Arrangement 7: adjacent composite tetrahedral units A and composite tetrahedral units B are connected by two shared inner The prisms of adjacent composite tetrahedral units A all face the center of the ring, that is, the cylindrical surfaces of the composite tetrahedral units A facing the center of the ring together constitute the inner ring surface, and adjacent composite tetrahedral units A share two inner faceplates 11 and one prism 15, which are connected by four synchronization rods 12; Arrangement method three: one of the edges of the composite tetrahedral units B faces the center of the ring, and the cylindrical surfaces opposite to the edges face the outside of the ring, that is, all the cylindrical surfaces facing the outside of the ring together constitute the outer ring surface, and adjacent composite tetrahedral units B share one prism 15 and two outer faceplates 21, which are connected by four synchronization rods 13.

[0043] The following is a further description of a single-degree-of-freedom double-ring truss deployable antenna mechanism based on a composite tetrahedron unit according to the present invention in conjunction with an embodiment:

[0044] 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 composite tetrahedral units A and composite tetrahedral units B in the overall mechanism and the length of each rod therein. When the two synchronous rods 12 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, the degree of freedom of the mechanism is zero, and 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.

[0045] The composite tetrahedral unit A and the composite tetrahedral unit B have different arrangements and different connection modes therebetween. There are three arrangements of the composite tetrahedral unit.

[0046] Embodiment 1:

[0047] like Figure 1As shown in FIG2 , the present invention provides a single-degree-of-freedom double-ring truss deployable antenna mechanism based on a composite tetrahedron unit, which includes N composite tetrahedron units A and composite tetrahedron units B with the same structure, N is an integer greater than or equal to 3, the composite tetrahedron unit A includes a tetrahedron unit 1 and a prism 15, the tetrahedron unit 1 is arranged in a face-symmetrical manner, and the tetrahedron units 1 are connected by the prism 15, the tetrahedron unit 1 includes an inner faceplate 11, a synchronization rod 12, a connecting rod 13, a Y-shaped faceplate 14, an outer faceplate 21 and a T-shaped faceplate 22, and the adjacent inner faceplates 11 are rotationally connected by the synchronization rod 12, and multiple The inner faceplates 11 are arranged in an equilateral or isosceles triangle, the Y-shaped faceplate 14 is located above the center of the triangle, the inner faceplates 11 are connected to the Y-shaped faceplates 14 through connecting rods 13, the outer faceplates 21 are connected end to end in sequence through synchronization rods 12, the outer faceplates 21 are connected to the T-shaped faceplates 22 through the connecting rods 13, the outer faceplates 21 are arranged in a plane-symmetrical manner and connected through prisms 15, the composite tetrahedral unit A and the composite tetrahedral unit B are connected through two shared inner faceplates 11, four synchronization rods 12, two prisms 15 and two outer faceplates 21, and the whole constitutes a double-ring truss deployable antenna mechanism.

[0048] The operation process of this embodiment is achieved as follows:

[0049] 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 composite tetrahedron unit A and the composite tetrahedron unit B are in a folded state, the synchronization rods 12, the connecting rods 13 and the prisms 15 are all close to each other, and the overall mechanism is folded into a cylinder, which effectively saves rocket launch space.

[0050] When the antenna reaches the designated position and starts working, each synchronization rod 12 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 12 form a straight line to achieve locking, keep the mechanism in the expanded state without shrinking, and become the supporting unit of the inner and outer rings. During the expansion process, each connecting rod 13 opens to both sides, the distance between the Y-shaped disc 14 and the inner disc 11 gradually decreases, and the distance between the T-shaped disc 22 and the outer disc 21 gradually decreases, pushing the inner disc 11 and the outer disc 21 to move outward along the radial direction of the cylinder, and the mechanism is expanded from a cylindrical structure to a circular ring.

[0051] Embodiment 2:

[0052] like Fig.13 and Fig.14As shown, the present invention provides a single-degree-of-freedom double-ring truss deployable antenna mechanism based on a composite tetrahedron unit, which includes N composite tetrahedron units A with the same structure, the composite tetrahedron unit A includes a tetrahedron unit 1 and a prism 15, and the tetrahedron units 1 are connected by the prism 15, the tetrahedron unit 1 includes an inner faceplate 11, a synchronization rod 12, a connecting rod 13, a Y-shaped faceplate 14, and an outer faceplate 21, adjacent inner faceplates 11 are rotationally connected by the synchronization rod 12, and the plurality of inner faceplates 11 are arranged in an equilateral or isosceles triangle, and the Y-shaped faceplate 14 is connected to the outer faceplate 21. 4 is located above the center of the triangle, the inner faceplate 11 is connected to the Y-shaped faceplate 14 through the connecting rod 13, and the outer faceplates 21 are connected end to end in sequence through the synchronization rod 12. The outer faceplates 21 are arranged in a plane-symmetrical manner and connected through the prism 15. The prisms of adjacent composite tetrahedral units A all face the ring center, that is, the cylindrical surfaces of the composite tetrahedral units A facing the ring center together constitute the inner ring surface. The two inner faceplates 11 and one prism 15 shared by adjacent composite tetrahedral units A are connected through four synchronization rods 12, and the whole constitutes a double-ring truss deployable antenna mechanism.

[0053] The operation process of this embodiment is achieved as follows:

[0054] The operation process of this embodiment is the same as that of the first embodiment. In this embodiment, the double-ring truss deployable antenna mechanism only includes the composite tetrahedron unit A, and the folded and unfolded state of the deployable antenna mechanism is the same as that in the first embodiment.

[0055] Embodiment three:

[0056] like Fig.15 and Fig.16 As shown, the present invention provides a single-degree-of-freedom double-ring truss deployable antenna mechanism based on a composite tetrahedron unit, which includes N composite tetrahedron units B with the same structure, the composite tetrahedron unit B includes a tetrahedron unit 1 and a prism 15, the tetrahedron unit 1 is arranged in a plane-symmetrical manner, and the tetrahedron units 1 are connected by the prism 15, the tetrahedron unit 1 includes an inner faceplate 11, a synchronization rod 12, a connecting rod 13, an outer faceplate 21 and a T-shaped faceplate 22, adjacent inner faceplates 11 are rotationally connected by the synchronization rod 12, and the plurality of inner faceplates 11 are arranged in an equilateral or isosceles triangle, and the T-shaped faceplate 22 is located at the center of the triangle. Above the inner faceplate 11, the inner faceplate 11 is connected to the T-shaped faceplate 22 through the connecting rod 13, and the outer faceplate 21 is connected end to end in sequence through the synchronization rod 12. The outer faceplate 21 is connected to the T-shaped faceplate 22 through the connecting rod 13. The outer faceplate 21 is arranged in a plane-symmetrical manner and is connected through the prism 15. One edge of the composite tetrahedral unit B faces the center of the ring, and the cylindrical surface opposite to the edge faces the outside of the ring, that is, all the cylindrical surfaces facing the outside of the ring together constitute the outer ring surface. Adjacent composite tetrahedral units B share a prism 15 and two outer faceplates 21, which are connected through four synchronization rods 12, and the whole constitutes a double-ring truss deployable antenna mechanism.

[0057] The operation process of this embodiment is achieved as follows:

[0058] The operation process of this embodiment is the same as that of the first embodiment. In this embodiment, the double-ring truss deployable antenna mechanism only has the composite tetrahedron unit B, and the folded and unfolded state of the deployable antenna mechanism is the same as that in the first embodiment.

[0059] The present invention provides a single-degree-of-freedom double-ring truss deployable antenna mechanism based on a composite tetrahedron unit, which overcomes the problem in the prior art that the peripheral truss mechanism has low rigidity and that the rigidity of the overall structure decreases more seriously with the increase of the antenna diameter. The single-degree-of-freedom double-ring truss deployable antenna mechanism has the advantages of few degrees of freedom, simple structure and large folding ratio, and can be widely used in modern industrial fields such as aerospace to meet the needs of different space missions.

[0060] 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 single-degree-of-freedom double-ring truss deployable antenna mechanism based on composite tetrahedron elements, characterized in that: It includes N composite tetrahedral units with the same structure, where N is an integer greater than or equal to 3. The composite tetrahedral unit comprises a tetrahedral unit and a prism. The tetrahedral units are arranged in a face-symmetrical manner and connected by prisms. The tetrahedral units comprise an inner faceplate, a synchronization rod, a connecting rod, a Y-shaped faceplate, an outer faceplate and a T-shaped faceplate. Adjacent inner faceplates are rotationally connected by a synchronization rod, and a plurality of inner faceplates are arranged in an equilateral or isosceles triangle. The Y-shaped faceplate is located above the center of the triangle. The inner faceplates are connected to the Y-shaped faceplates by connecting rods respectively. The outer faceplates are connected end to end in sequence by synchronization rods. The outer faceplates are connected to the T-shaped faceplates by connecting rods. The outer faceplates are arranged in a face-symmetrical manner and connected by prisms. The composite tetrahedral units have different connection modes due to different arrangement modes. The composite tetrahedral units are connected by a common inner faceplate, synchronization rod, connecting rod, prism and outer faceplate to form a double-ring truss structure as a whole. The inner faceplate is located on the inner annular surface, and both the inner faceplate and the outer faceplate are double-layer symmetrical structures. The first layer of the inner faceplate is provided with four double-notch forks, and the notches are provided with through holes for inserting the ends of the synchronization rods and connecting them through a rotating pair. Two synchronization rods form a group, and the synchronization rods are connected through a rotating pair. Two notches form a group, and the angle between the notches in the same group is the base angle of the isosceles or equilateral triangle on the bottom surface of the tetrahedron unit, and the base angle is , the vertex angle of an isosceles or equilateral triangle is The second layer of the inner faceplate is provided with three double-notched forks, which are used to insert the ends of the connecting rods and connect through a rotating pair, and the center lines of the three notches coincide with the bisectors of the angles between the four notches of the first layer. The angles between the notches of the second layer are , a groove is also provided on the first layer of the inner flower disc, the first end of the prism is fixedly connected to the groove on the inner flower disc, and the second end of the prism is fixedly connected to the groove provided on the inner flower disc which is arranged in a plane symmetrically; The outer layer faceplate is located on the outer ring surface. The first layer of the outer layer faceplate is provided with four double-notch forks. The outer layer faceplate divides the double-notch forks into two groups by the middle symmetry plane. The angle between the double-notch forks in the same group is , the included angle between two adjacent groups of notches is the vertex angle of an isosceles or equilateral triangle is The second layer of the outer faceplate is provided with three notches, and the angle between the notches is ; The Y-shaped flower disc and the T-shaped flower disc are both provided with three double-notch forks, and the notches are both provided with through holes. The Y-shaped flower disc and the T-shaped flower disc are both plane-symmetrical structures as a whole. The middle symmetry plane of the Y-shaped flower disc and the T-shaped flower disc coincides with the middle fork symmetry plane. There is a fork on each side of the middle symmetry plane. The angle between the fork symmetry plane on each side and the middle symmetry plane is , the angle between the symmetry planes of the two side forks is ; There are three arrangements of the composite tetrahedral unit. Arrangement 1: The adjacent composite tetrahedral unit A and composite tetrahedral unit B, the cylindrical surface of the composite tetrahedral unit A faces the ring center, the cylindrical surface of the composite tetrahedral unit B faces the outside of the ring, all the cylindrical surfaces facing the ring center together constitute the inner ring surface, all the cylindrical surfaces facing the outside of the ring center together constitute the outer ring surface, and the adjacent composite tetrahedral unit A and composite tetrahedral unit B are connected by two shared inner layer flower disks, two outer layer flower disks, two prisms and four synchronization rods; Arrangement 2: The adjacent The prisms of the composite tetrahedral unit A all face the center of the ring, that is, the cylindrical surfaces of the composite tetrahedral unit A facing the center of the ring together constitute the inner ring surface, and adjacent composite tetrahedral units A share two inner flower disks and one prism, and are connected by four synchronization rods; Arrangement method three: one of the edges of the composite tetrahedral unit B faces the center of the ring, and the cylindrical surfaces opposite to the edges face the outside of the ring, that is, all cylindrical surfaces facing the outside of the ring together constitute the outer ring surface, and adjacent composite tetrahedral units B share a prism and two outer flower disks, and are connected by four synchronization rods.

2. The single-degree-of-freedom double-ring truss deployable antenna mechanism based on composite tetrahedron elements according to claim 1, characterized in that: The synchronization rod, connecting rod and prism in the tetrahedral unit should all satisfy a specific proportional relationship, and the sizes of the synchronization rod, connecting rod and prism are reasonably adjusted according to the angles between the branches on the inner faceplate, Y-shaped faceplate, outer faceplate and T-shaped faceplate.

3. The single-degree-of-freedom double-ring truss deployable antenna mechanism based on composite tetrahedron unit according to claim 1, characterized in that: The deployable antenna mechanism can be semi-folded and fully folded by adjusting the synchronization rod, the connecting rod and the prism. When the deployable antenna mechanism is in the semi-folded state, the distance between the Y-shaped faceplates or the T-shaped faceplates gradually decreases, and the volume of the composite tetrahedron unit is reduced. When the deployable antenna mechanism is in the folded state, the planes where the inner faceplate and the outer faceplate are located remain horizontal, and the synchronization rods and the connecting rods are close to each other and are in the minimum volume state, and the whole is shrunk into a cylindrical structure.

4. The single-degree-of-freedom double-ring truss deployable antenna mechanism based on composite tetrahedron units according to any one of claims 1 to 3, characterized in that: The synchronous rod, the connecting rod and the prism are all made of carbon fiber composite material or aviation aluminum alloy material.

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