Double-layer annular deployable peripheral truss with tail end self-locking function

Abstract

The invention discloses a double-layer annular deployable peripheral truss with a self-locked tail end, which comprises an annular peripheral truss formed by splicing a plurality of double-layer arc shear fork assemblies and a driving mechanism for driving the annular peripheral truss to unfold or fold, and self-locking mechanisms are arranged at the splicing starting end and the splicing tail end of the annular peripheral truss. The double-layer arc-shaped shear fork assembly is formed by hinging a first single-layer arc-shaped shear fork assembly and a second single-layer arc-shaped shear fork assembly. The deployable mechanism disclosed by the invention has good load capacity and rigidity performance, and can adapt to application requirements of a peripheral truss of a spatial large-scale deployable cable net antenna.

Description

Technical Field

[0001] The invention relates to the field of robot mechanism, and in particular to a double-layer annular expandable peripheral truss with self-locking ends. Background Art

[0002] The Chinese invention patent with publication number CN109659659A discloses a ring truss-type deployable antenna mechanism based on 3R-RRP mechanism units, including 2N 3R-RRP mechanism units, 2N 3R-RRP mechanism units are grouped in pairs, connected by a common support rod, a fixed node connector and a motion node connector, to form N combined mechanism units; the N combined mechanism units have exactly the same structure, and adjacent combined mechanism units are connected by a common support rod and two fixed node connectors to form a multi-faceted ring truss mechanism; the 3R-RRP mechanism unit mainly includes two support rods, a long connecting rod, two short connecting rods, three fixed node connectors and a motion node connector; wherein the length of the short connecting rod is half of the length of the long connecting rod, and the length of the supporting rod is greater than three times the length of the short connecting rod. The overall mechanism structure of the present invention is simple, flexible in movement, and has a low processing and manufacturing cost. It can be used as a support mechanism and is well applied in the field of large-caliber satellite antennas.

[0003] The main shortcomings of the existing antenna peripheral trusses are reflected in the following aspects: First, most antenna peripheral trusses lack the description of the driving characteristics, and only analyze from the perspective of folding and unfolding performance, which is unreasonable. The design of the drive system is an important part of antenna design. A complex drive system will make the overall mass of the antenna peripheral truss too high, which is very unfavorable for space transportation and weakens its practical value. Second, in practical applications, the antenna peripheral trusses need to have good rigidity. Most antenna peripheral trusses only consider the size after unfolding, and do not take the rigidity of the antenna peripheral truss into consideration. Similarly, in order to meet the actual needs of the antenna rack, the rigidity of the satellite-borne antenna peripheral truss should be designed. Third, the antenna needs to maintain a stable unfolded state to work during operation, but most of the antenna peripheral trusses currently only explain the unfolding process, lacking instructions on how to make the antenna unfold stably. Fourth, most of the antenna peripheral trusses are currently designed in a way that polygons approximate circles, and this design usually wastes more space than circular antennas. Therefore, in order to avoid the shortcomings of the prior art, it is necessary to improve the prior art. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings and deficiencies in the prior art and to provide a double-layer annular expandable peripheral truss with strong rigidity, large folding and unfolding ratio and self-locking end.

[0005] The present invention is achieved through the following technical solutions: a double-layer annular expandable peripheral truss with self-locking ends, including an annular peripheral truss formed by connecting a plurality of double-layer arc-shaped scissor-fork assemblies and a driving mechanism for driving the annular peripheral truss to expand or collapse, the connecting beginning and the connecting end of the annular peripheral truss are provided with a self-locking mechanism, and the double-layer arc-shaped scissor-fork assembly is hingedly formed by a first single-layer arc-shaped scissor-fork assembly and a second single-layer arc-shaped scissor-fork assembly.

[0006] Furthermore, the self-locking mechanism includes a self-locking seat and a sliding rod, the starting end of the sliding rod slides in the self-locking seat, the starting end side wall of the self-locking seat is provided with a groove-facing locking groove, the upper end of the groove-facing locking groove is provided with a longitudinal locking groove, and elastic components and self-locking rods are sequentially arranged in the longitudinal locking groove, the self-locking rod telescopically runs inside and outside the longitudinal locking groove, the end of the sliding rod and the starting end of the self-locking seat are respectively rotatably connected to the connecting starting end of the annular peripheral truss, and the connecting end of the annular peripheral truss is clamped in the transverse locking groove.

[0007] Further, the first single-layer arc scissors assembly includes a first scissors rod and a second scissors rod, the first scissors rod is hinged to the middle part of the second scissors rod, and the second single-layer arc scissors assembly includes a third scissors rod and a fourth scissors rod, and the middle parts of the third scissors rod and the fourth scissors rod are hinged; the starting ends of the first scissors rod and the third scissors rod are respectively hinged to the ends of the adjacent second scissors rod and the fourth scissors rod, and the starting ends of the second scissors rod and the fourth scissors rod are respectively hinged to the ends of the adjacent first scissors rod and the third scissors rod; a number of connecting rods are provided between the first single-layer arc scissors assembly and the second single-layer arc scissors assembly, and the two ends of the number of connecting rods are respectively rotatably connected to the first single-layer arc scissors assembly and the second single-layer arc scissors assembly.

[0008] Further, a first connecting rod is rotatably connected between the starting ends of the first scissors rod and the third scissors rod, a second connecting rod is rotatably connected between the ends of the first scissors rod and the third scissors rod, a third connecting rod is rotatably connected between the second scissors rod and the starting ends of the fourth scissors rod, a fourth connecting rod is rotatably connected between the ends of the second scissors rod and the fourth scissors rod, a fifth connecting rod is rotatably connected between the middle parts of the first scissors rod and the second scissors rod and the middle parts of the third scissors rod and the fourth scissors rod, and the first connecting rod, the second connecting rod, the third connecting rod and the fourth connecting rod constitute a common connecting assembly of two adjacent double-layer arc scissors assemblies.

[0009] Furthermore, the end of the sliding rod and the beginning of the self-locking seat are rotatably connected to the fourth connecting rod and the second connecting rod at the beginning of the connection of the annular peripheral truss respectively, and the first connecting rod at the end of the connection of the annular peripheral truss is clamped in the transverse locking groove.

[0010] Furthermore, the elastic component is a return spring.

[0011] Furthermore, a transition cut surface is provided on the outer side of the extended end of the self-locking rod.

[0012] Furthermore, the self-locking mechanism is provided with a clamping structure which limits the extension length of the self-locking rod.

[0013] Furthermore, the driving mechanism is installed on the double-layer arc scissors assembly in the middle of the annular peripheral truss, and the driving mechanism includes a driving rod, a fixed seat installed at one end of the driving rod, and a sliding seat installed at the other end of the driving rod. The fixed seat and the sliding seat are hinged at the beginning or end of the double-layer arc scissors assembly.

[0014] Furthermore, the driving mechanism also includes a first articulated seat and a second articulated seat, the first articulated seat and the second articulated seat are fixedly installed at the beginning or end of the double-layer arc-shaped scissors fork assembly, the fixed seat is hinged to the first articulated seat, and the sliding seat is hinged to the second articulated seat.

[0015] Compared with the prior art, the peripheral truss of the deployable antenna of the present invention adopts a truss structure, so that the deployable mechanism has good load capacity and stiffness performance, and can adapt to the application requirements of the peripheral truss of a large-scale deployable cable net antenna in space.

[0016] The peripheral truss of the deployable antenna of the present invention adopts an arc-shaped scissor-fork mechanism, which has a large folding and unfolding ratio. At the same time, a circular truss is formed in the deployed state, which improves the working efficiency of the antenna compared to the polygonal ring truss close to a circle. In addition, the size of the peripheral truss is determined by the curvature of the arc-shaped scissor-fork mechanism. The larger the curvature radius of the arc-shaped scissor-fork, the larger the size of the peripheral truss.

[0017] The peripheral truss of the deployable antenna of the present invention has few degrees of freedom, including only one degree of freedom. Through the design of the driving system, only one driver is needed to realize the deployment of the annular truss.

[0018] The deployable antenna peripheral truss of the present invention adopts an end self-locking mechanism. When the peripheral truss is deployed to the end contact, self-locking is formed between the two ends, so that the peripheral truss fully utilizes its stability and enhances the structural rigidity of the peripheral truss.

[0019] The peripheral truss of the deployable antenna of the present invention adopts a double-layer truss structure, which further enhances the structural rigidity of the peripheral truss. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 It is a schematic structural diagram of the first single-layer arc-shaped scissor assembly of the double-layer annular expandable peripheral truss capable of self-locking at the end of the present invention;

[0022] Figure 2 It is a schematic diagram of the side structure of the first single-layer arc-shaped scissor assembly of the double-layer annular expandable peripheral truss with end self-locking of the present invention;

[0023] Figure 3 It is a schematic structural diagram of a double-layer arc-shaped scissor assembly of a double-layer annular expandable peripheral truss with end self-locking capability according to the present invention;

[0024] Figure 4 It is a schematic diagram of the self-locking mechanism structure of the double-layer annular expandable peripheral truss capable of self-locking at the end of the present invention;

[0025] Figure 5 It is a schematic diagram of the unfolded structure of the annular peripheral truss of the double-layer annular unfoldable peripheral truss capable of self-locking at the ends of the present invention;

[0026] Figure 6 It is a schematic diagram of the self-locking and unfolding structure of the annular peripheral truss end of the double-layer annular unfoldable peripheral truss with self-locking end of the present invention;

[0027] Figure 7 for Figure 6 A magnified schematic diagram of part A;

[0028] Figure 8 It is a schematic diagram of the self-locking and folding structure of the annular peripheral truss ends of the double-layer annular expandable peripheral truss with self-locking ends according to the present invention;

[0029] Fig. 9 It is a schematic diagram of the side structure of the self-locking and folding end of the annular peripheral truss of the double-layer annular expandable peripheral truss of the present invention;

[0030] Fig.10 The present invention is a schematic structural diagram of a double-layer annular expandable peripheral truss capable of self-locking at the ends when applied to a space satellite in an expanded state.

[0031] In the figure: 1-double-layer arc-shaped scissors fork assembly; 2-annular peripheral truss; 3-driving mechanism; 4-self-locking mechanism; 5-first single-layer arc-shaped scissors fork assembly; 6-second arc-shaped scissors fork assembly; 7-self-locking seat; 8-sliding rod; 9-groove locking groove; 10-elastic component; 11-self-locking rod; 12-first scissors fork rod; 13-second scissors fork rod; 14-third scissors fork rod; 15-fourth scissors fork rod; 16-first connecting rod; 17-second connecting rod; 18-third connecting rod; 19-fourth connecting rod; 20-fifth connecting rod; 21-driving rod; 22-fixed seat; 23-sliding seat; 24-first articulated seat; 25-second articulated seat. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Antennas are important components of various spacecraft, and they are mainly used for transmitting and receiving signals. The size of the antenna's peripheral truss will directly affect the antenna's working efficiency. Therefore, in order to meet actual needs, the antenna's peripheral truss needs to be larger in size when in working condition. However, during transportation, due to the small carrying capacity of the launch vehicle or space shuttle, the antenna cannot be transported in a fixed unfolded posture. It needs to be launched into space in a compact folded state, and then unfolded by a drive device. This requires the antenna's peripheral truss to have a large folding ratio. At the same time, after meeting the larger folding ratio, it is also necessary to design its drive system. An overly complex drive system will increase the difficulty of drive control, and too many drive devices will greatly increase the overall mass of the antenna, which obviously does not meet its actual needs. When the antenna enters the working state, due to the complexity of the working environment, the antenna ring truss also needs to have better rigidity to adapt to avoid affecting the stability of the antenna due to structural deformation.

[0034] In view of the problems existing in the antenna peripheral truss in the prior art, the present invention takes the antenna peripheral truss as the research object, and proposes a double-layer annular expandable peripheral truss with a large folding and unfolding ratio, a single-degree-of-freedom driving characteristic and end self-locking. The annular truss of the mechanism is formed by an arc-shaped scissors-fork mechanism, and the size of the annular truss depends on the curvature of the arc-shaped scissors-fork mechanism. On this basis, a single-degree-of-freedom driving mechanism is designed to complete the expansion of the annular truss. Furthermore, in order to enable the antenna annular truss to maintain an expanded working state, an end self-locking mechanism is designed. When the drive system controls the annular truss to expand until the two ends are in contact, self-locking will be formed, thereby enhancing the rigidity. In order to meet its ability to adapt to complex working conditions, a double-layer annular truss is designed to ensure the reliable structural rigidity of the antenna and enhance its environmental adaptability. Finally, a double-layer annular expandable peripheral truss with end self-locking is formed.

[0035] like Figures 1 to 10 The double-layer annular expandable peripheral truss with self-locking at the end of the present invention comprises an annular peripheral truss 2 formed by connecting a plurality of double-layer arc scissor assemblies 1 and a driving mechanism 3 for driving the annular peripheral truss 2 to expand or collapse. The connecting start and the connecting end of the annular peripheral truss 2 are provided with a self-locking mechanism 4. The double-layer arc scissor assembly 1 is hinged by a first single-layer arc scissor assembly 5 and a second single-layer arc scissor assembly 6. In order to achieve foldability and a large folding and unfolding ratio, an arc scissor assembly is used. At the same time, in order to form the annular peripheral truss 2 during the unfolding movement, a special arc design is performed on the arc scissor assembly. The spherical surface is divided by spherical segmentation technology to form an arc scissor mechanism with an offset angle. The annular peripheral truss 2 can be formed by connecting multiple sets of arc scissor mechanisms. Such annular peripheral truss 2 forms a circular ring truss while maintaining a single degree of freedom and a large folding and unfolding ratio, avoiding the use of multiple drivers and effectively reducing the mass of the annular peripheral truss 2. In order to achieve good rigidity of the annular peripheral truss 2, a double-layer truss is designed, and a self-locking mechanism 4 is designed at the end of the annular peripheral truss 2. When both ends are fully unfolded, the ends are self-locked to enhance its rigidity. In the simulation verification of the antenna, a cable net is arranged on the annular peripheral truss 2 and a membrane is laid. From the effect point of view, the annular peripheral truss 2 can meet the actual needs of the antenna. The arc-shaped scissor mechanism can form an envelope angle θ when it is unfolded.

[0036] The self-locking mechanism 4 includes a self-locking seat 7 and a sliding rod 8. The starting end of the sliding rod 8 slides in the self-locking seat 7. The starting end side wall of the self-locking seat 7 is provided with a groove-oriented locking groove 9. The upper end of the groove-oriented locking groove 9 is provided with a longitudinal locking groove. An elastic component 10 and a self-locking rod 11 are sequentially arranged in the longitudinal locking groove. The self-locking rod 11 telescopically runs inside and outside the longitudinal locking groove. The end of the sliding rod 8 and the starting end of the self-locking seat 7 are respectively rotatably connected to the connecting starting end of the annular peripheral truss 2, and the connecting end of the annular peripheral truss 2 is clamped in the transverse locking groove 9.

[0037] The first single-layer arc scissors assembly 5 includes a first scissors rod 12 and a second scissors rod 13, and the first scissors rod 12 is hinged to the middle part of the second scissors rod 13; the second single-layer arc scissors assembly 6 includes a third scissors rod 14 and a fourth scissors rod 15, and the middle parts of the third scissors rod 14 and the fourth scissors rod 15 are hinged; the starting ends of the first scissors rod 12 and the third scissors rod 14 are hinged to the ends of the adjacent second scissors rod 13 and the fourth scissors rod 15, respectively, and the starting ends of the second scissors rod 13 and the fourth scissors rod 15 are hinged to the ends of the adjacent first scissors rod 12 and the third scissors rod 14, respectively; a plurality of connecting rods are provided between the first single-layer arc scissors assembly 5 and the second single-layer arc scissors assembly 6, and the two ends of the plurality of connecting rods are rotatably connected to the first single-layer arc scissors assembly 5 and the second single-layer arc scissors assembly 6, respectively.

[0038] A first connecting rod 16 is rotatably connected between the starting ends of the first scissors rod 12 and the third scissors rod 14, a second connecting rod 17 is rotatably connected between the ends of the first scissors rod 12 and the third scissors rod 14, a third connecting rod 18 is rotatably connected between the second scissors rod 13 and the starting ends of the fourth scissors rod 15, a fourth connecting rod 19 is rotatably connected between the ends of the second scissors rod 13 and the fourth scissors rod 15, a fifth connecting rod 20 is rotatably connected between the middle parts of the first scissors rod 12 and the second scissors rod 13 and the middle parts of the third scissors rod 14 and the fourth scissors rod 15, the first connecting rod 16, the second connecting rod 17, the third connecting rod 18 and the fourth connecting rod 19 constitute a common connecting assembly of two adjacent double-layer arc scissors assemblies 1.

[0039] The end of the slide bar 8 and the beginning of the self-locking seat 7 are rotatably connected to the fourth connecting rod 19 and the second connecting rod 17 at the beginning of the connection of the annular peripheral truss 2, respectively, and the first connecting rod 16 at the end of the connection of the annular peripheral truss 2 is clamped in the transverse locking groove 9. When the annular peripheral truss 2 is expanded to both sides, the slide bar 8 on the beginning of the connection slides into the self-locking seat 7; when the beginning and the end of the connection of the annular peripheral truss 2 are close to each other, the first connecting rod 16 on the end of the expansion presses the protruding end of the self-locking rod 11, and when the first connecting rod 16 enters the transverse locking groove 9, the self-locking rod 11 slides upward due to the action of the elastic component 10, and when the first connecting rod 16 enters the transverse locking groove 9, the self-locking rod 11 slides downward due to the action of the elastic component 10, forming a self-locking.

[0040] The elastic component 10 is a return spring.

[0041] The outer side of the extended end of the self-locking rod 11 is provided with a transition cut surface to facilitate the first connecting rod 16 to enter the transverse locking groove 9.

[0042] The self-locking mechanism 4 is provided with a clamping structure for limiting the extension length of the self-locking rod 11 .

[0043] The driving mechanism 3 is installed on the double-layer arc scissor assembly 1 in the middle of the annular peripheral truss 2. The driving mechanism 3 includes a driving rod 21, a fixed seat 22 installed at one end of the driving rod 21, and a sliding seat 23 installed at the other end of the driving rod 21. The fixed seat 22 and the sliding seat 23 are hinged at the beginning or end of the double-layer arc scissor assembly 1. When the sliding seat 23 moves downward, the connecting beginning and the connecting end of the annular peripheral truss 2 are slowly unfolded to both sides respectively. When fully unfolded, the connecting beginning and the connecting end are opened to be self-locked through the self-locking mechanism 4.

[0044] The driving mechanism 3 also includes a first articulated seat 24 and a second articulated seat 25, which are fixedly installed at the beginning or end of the double-layer arc-shaped scissors assembly 1, the fixed seat 22 is hinged on the first articulated seat 24, and the sliding seat 23 is hinged on the second articulated seat 25.

[0045] The space ring-shaped large-scale expandable peripheral truss is in a folded state during transportation. When it enters the service space environment and is expanded, the moving pair can be driven by a simple and reliable driver such as a servo motor or a nut screw. Under the action of the driving force, the space ring-shaped large-scale expandable peripheral truss slowly expands. When the ends are in contact, self-locking is formed by the self-locking mechanism 4 to fix the peripheral truss. In general, the space ring-shaped large-scale expandable peripheral truss has a large folding and expansion ratio and excellent single-degree-of-freedom driving characteristics. The arc-shaped scissors-fork mechanism forms a circular ring truss. The self-locking mechanism 4 makes the antenna stable and reliable in operation, reduces the influence of prestress on the truss, strengthens the stiffness of the ring truss, and the double-layer ring truss ensures the stiffness performance requirements required for on-orbit operation.

[0046] The present invention is a space annular large-scale deployable peripheral truss, which has the advantages of high strength, high structural reliability, few degrees of freedom, simple driving system, etc., and can be widely used in satellite-borne space annular large-scale deployable peripheral truss cable net antennas.

[0047] In order to achieve a large folding and expansion ratio of a spatial annular large-scale expandable peripheral truss, the present invention adopts an arc-shaped scissors-type mechanism. The scissors-type mechanism has the characteristics of modular structure, strong telescopic performance, good mechanical properties, simple structure, high rigidity, etc. It belongs to the category of expandable mechanism, and its driving process is relatively simple and the structural reliability is high. It is suitable for forming a spatial expandable mechanism with a large folding and expansion ratio.

[0048] In order to realize the single-degree-of-freedom driving characteristics of the large-scale deployable peripheral truss in the space ring, the trusses on both sides can be deployed simultaneously through the single-degree-of-freedom movement of the driving mechanism. The single-degree-of-freedom driving method can effectively reduce the difficulty of designing the control system of the peripheral truss.

[0049] In order to achieve excellent rigidity of the large-scale deployable peripheral truss in the space ring, the present invention adopts a truss-type mechanism, an end self-locking mechanism 4 and a double-layer truss. The truss-type structure enables the deployable mechanism to have good rigidity performance and load capacity; the end self-locking mechanism 4 enables the mechanism to form a 0-degree-of-freedom truss-type structure from a truss mechanism in a movable state, which greatly improves the rigidity of the large-scale deployable peripheral truss in the space ring; at the same time, the double-layer truss is used to further increase the rigidity of the ring truss. This is very important for the ability of the cable net antenna to maintain the surface accuracy.

[0050] In order to realize a large-scale spatial ring-shaped expandable peripheral truss to improve the working efficiency of the antenna, the arc-shaped scissors mechanism is connected in series to finally form a circular ring truss to meet its actual needs.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A double-layer annular expandable peripheral truss with self-locking ends, characterized in that: It includes an annular peripheral truss formed by connecting a plurality of double-layer arc-shaped scissor-fork assemblies and a driving mechanism for driving the annular peripheral truss to expand or collapse. The connecting start and end of the annular peripheral truss are provided with a self-locking mechanism. The double-layer arc-shaped scissor-fork assembly is hingedly connected by a first single-layer arc-shaped scissor-fork assembly and a second single-layer arc-shaped scissor-fork assembly.

2. The double-layer annular expandable peripheral truss with end self-locking according to claim 1, characterized in that: The self-locking mechanism includes a self-locking seat and a sliding rod. The starting end of the sliding rod slides in the self-locking seat. The starting end side wall of the self-locking seat is provided with a slot-towards locking groove. The upper end of the slot-towards locking groove is provided with a longitudinal locking groove. Elastic components and self-locking rods are sequentially arranged in the longitudinal locking groove. The self-locking rod telescopically runs inside and outside the longitudinal locking groove. The end of the sliding rod and the starting end of the self-locking seat are respectively rotatably connected to the connecting starting end of the annular peripheral truss, and the connecting end of the annular peripheral truss is clamped in the transverse locking groove.

3. The double-layer annular expandable peripheral truss with end self-locking according to claim 2, characterized in that: The first single-layer arc-shaped scissors assembly includes a first scissors rod and a second scissors rod, the first scissors rod is hinged to the middle part of the second scissors rod, and the second single-layer arc-shaped scissors assembly includes a third scissors rod and a fourth scissors rod, the middle parts of the third scissors rod and the fourth scissors rod are hinged; the starting ends of the first scissors rod and the third scissors rod are respectively hinged to the ends of the adjacent second scissors rod and the fourth scissors rod, and the starting ends of the second scissors rod and the fourth scissors rod are respectively hinged to the ends of the adjacent first scissors rod and the third scissors rod; a plurality of connecting rods are provided between the first single-layer arc-shaped scissors assembly and the second single-layer arc-shaped scissors assembly, and the two ends of the plurality of connecting rods are respectively rotatably connected to the first single-layer arc-shaped scissors assembly and the second single-layer arc-shaped scissors assembly.

4. The double-layer annular expandable peripheral truss with end self-locking according to claim 3, characterized in that: A first connecting rod is rotatably connected between the starting ends of the first scissors rod and the third scissors rod, a second connecting rod is rotatably connected between the ends of the first scissors rod and the third scissors rod, a third connecting rod is rotatably connected between the second scissors rod and the starting ends of the fourth scissors rod, a fourth connecting rod is rotatably connected between the ends of the second scissors rod and the fourth scissors rod, a fifth connecting rod is rotatably connected between the middle parts of the first and second scissors rods and the middle parts of the third and fourth scissors rods, the first connecting rod, the second connecting rod, the third connecting rod and the fourth connecting rod constitute a common connecting assembly of two adjacent double-layer arc scissors assemblies.

5. The double-layer annular expandable peripheral truss with end self-locking according to claim 4, characterized in that: The end of the sliding rod and the beginning of the self-locking seat are rotatably connected to the fourth connecting rod and the second connecting rod at the beginning of the connection of the annular peripheral truss respectively, and the first connecting rod at the end of the connection of the annular peripheral truss is clamped in the transverse locking groove.

6. The double-layer annular expandable perimeter truss with end self-locking according to claim 2, characterized in that: The elastic component is a return spring.

7. The double-layer annular expandable perimeter truss with end self-locking according to claim 2, characterized in that: A transition cut surface is arranged on the outer side of the extended end of the self-locking rod.

8. The double-layer annular expandable perimeter truss with end self-locking according to claim 2, characterized in that: The self-locking mechanism is provided with a clamping structure which limits the extension length of the self-locking rod.

9. The double-layer annular expandable perimeter truss with end self-locking according to claim 1, characterized in that: The driving mechanism is installed on the double-layer arc scissors assembly in the middle of the annular peripheral truss. The driving mechanism includes a driving rod, a fixed seat installed at one end of the driving rod and a sliding seat installed at the other end of the driving rod. The fixed seat and the sliding seat are hinged at the beginning or end of the double-layer arc scissors assembly.

10. The double-layer annular expandable perimeter truss capable of self-locking at the ends according to claim 9, characterized in that: The driving mechanism also includes a first articulated seat and a second articulated seat, wherein the first articulated seat and the second articulated seat are fixedly installed at the beginning or end of the double-layer arc-shaped scissors fork assembly, the fixed seat is hinged to the first articulated seat, and the sliding seat is hinged to the second articulated seat.

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