Large-aperture reflector supporting structure suitable for multi-angle gravitational fields

Abstract

A large-aperture reflector supporting structure adapted to a multi-angle gravity field relates to the field of supporting design of a large-aperture reflector assembly for space optical remote sensing, is connected to the back of a reflector, and comprises a triangular back plate, three whiffletree supporting structures and three radial supporting structures, the three whiffletree supporting structures and the three radial supporting structures are connected to three corners of the triangular back plate respectively, three circular nesting holes are formed in the back of the reflecting mirror, the ends, facing the reflecting mirror, of the radial supporting structures are bonded to the circular nesting holes, each whiffletree supporting structure comprises a plurality of bonding pads, and the bonding pads are bonded to the back of the reflecting mirror through glue injection. And the supporting structure is compact in structure and high in rigidity, so that when the optical axis of the reflector is placed at different angles relative to the gravity direction, high reflector surface shape quality is easy to realize.

Description

Technical Field

[0001] The present application belongs to the field of support design of large-aperture reflector components for space optical remote sensing, and in particular relates to a large-aperture reflector support structure that can adapt to gravity fields at various angles. Background Art

[0002] The whiffletree support structure is often used to support large-aperture reflectors. Commonly used whiffletree support structures include 6-point support, 9-point support, 18-point support, 27-point support and 36-point support. The whiffletree support structure can only constrain the three degrees of freedom of the large-aperture TZ, Rx and Ry. If you want to constrain the camera's 6 degrees of freedom and achieve arbitrary placement of the large-aperture reflector, and ensure that the surface shape meets the requirements when subjected to gravity, you generally need to add 6 flexible rods on the side of the large-aperture reflector. The 6 flexible rods constrain the three degrees of freedom of TX, TY and RZ. Such as the support of the Sofia primary mirror, Figure 1 As shown. An 18-point whiffletree support at the bottom and three A Frame supports on the side of the reflector are used. The 18-point whiffletree support at the bottom only constrains the three degrees of freedom of TZ, Rx and Ry, and the three A Frame supports on the side constrain the three degrees of freedom of TX, TY and RZ.

[0003] The three-point support position where the whiffletree of this support structure finally converges is far away from the flexible support points around the reflector. In order to ensure the support stiffness, it is necessary to add a very rigid and heavy ring around the primary mirror, which makes the outer contour size of the entire reflector larger and the weight of the support structure heavier, which is extremely unfavorable for the lightweight design of the support structure.

[0004] like Figure 2 As shown in Figures a and b, due to the limitation of volume and weight, the support for large-aperture reflectors in current space cameras can only ensure that the reflectors meet the requirements for use when the optical axis is horizontal or vertical under the action of gravity. In many tests and experiments on the ground, not only is the shape of the reflector in the horizontal state of the optical axis required to be good, but the shape of the reflector in the vertical state of the optical axis must also meet the requirements. (Theoretically, the same support structure has a surface shape of Rms1 in the vertical state of the optical axis and Rms2 in the horizontal state of the optical axis. Then, when the optical axis and gravity form an arbitrary angle θ, the surface shape of the primary mirror is Rmsθ=((Rms1×sinθ) 2 +(Rms2×cosθ) 2 ) 1 / 2 Since the space camera can only meet the surface shape under the action of gravity in one direction, when the space camera is placed at a certain angle to the direction of gravity, the surface shape cannot meet the requirements, and additional complex or bulky unloading tooling is required to ensure that the surface shape of the reflector meets the requirements when tested at different angles.

[0005] For large-aperture astronomical telescopes used on the ground, the main mirror's surface shape can meet the requirements under different gravity effects. However, since there is no weight limit for astronomical telescopes, the main mirror is generally unloaded by hanging a weight on the bottom or side, or multiple brakes are used to actively control the mirror's surface shape. This support method is not only bulky and heavy, but also difficult to meet the volume and weight requirements of space cameras. Summary of the invention

[0006] The technical problem solved by this application is: to overcome the shortcomings of the prior art, to provide a large-aperture reflector support structure that adapts to gravity fields at various angles, to achieve quasi-static support of the reflector by changing the form and position of the reflector circumferential support structure based on the improved support structure of whiffletree support, and to achieve a compact support structure with high rigidity, so that when the reflector optical axis is placed at different angles relative to the gravity direction, it is easy to achieve a high reflector surface quality. It can be applied to the support design of large-aperture reflectors for space cameras.

[0007] The technical solutions provided by this application are as follows:

[0008] A large-aperture reflector support structure adaptable to gravity fields of various angles is connected to the back of the reflector, comprising a triangular back plate, three whiffletree support structures and three radial support structures, wherein the three whiffletree support structures and the three radial support structures are respectively connected to the three corners of the triangular back plate, and the back of the reflector has three circular nesting holes, and the ends of the radial support structures facing the reflector are bonded to the circular nesting holes, and each whiffletree support structure comprises a plurality of bonding pads, which are bonded to the back of the reflector by glue injection.

[0009] The whiffletree support structure also includes a lever beam, a triangular support block, a support rod rubber cup and a flexible support rod. The lever beam is rotatably connected to the triangular back plate, and the rotation axes of the lever beam are in the same plane. Two triangular support blocks are provided, and the two triangular support blocks are respectively connected to the two ends of the lever beam facing the surface of the reflector. Each corner of the triangular support block is fixedly connected to a support rod rubber cup, and the support rod rubber cup is provided with a through hole. The end of the flexible support rod is inserted into the through hole, and the through hole and the outside of the flexible support rod are fixed by glue injection. The adhesive pad is connected to one end of the flexible support rod facing the back of the reflector.

[0010] The whiffletree support structure also includes a flexible joint hinge, through which the triangular support block is connected to the lever beam. The flexible joint hinge has two rotation axes, an x-axis and a y-axis, so that the triangular support block and the lever beam can achieve rotational freedom in two directions around the x-axis and around the y-axis.

[0011] The three radial support structures are distributed at 120° relative to the center of the reflector, and each radial support structure includes a nest, a flexible sheet, a limit block, a movable plate and a cone beam, the cone beam is connected to the surface of the triangular back plate facing the back of the reflector, and the movable plate is connected to the end of the cone beam away from the triangular back plate; the nest is bonded to the nesting hole of the reflector by epoxy glue, a limit ring is arranged on the inner side of the nest, the limit block is connected to the inner side of the nest, and the limit block is located on the side of the limit ring away from the reflective surface of the reflector, the flexible sheet is installed on the inner side of the nest, and an installation ring is provided on the edge of the flexible sheet, the installation ring is located between the limit ring and the limit block, and the movable plate is located between the flexible sheet and the limit block; the central area of ​​the flexible sheet is deformable in the normal direction of the plane.

[0012] The flexible sheet is provided with at least two grooves, which start from the edge of the flexible sheet and extend in a planar spiral manner gradually approaching the center of the flexible sheet.

[0013] The thickness of the flexible part of the flexible sheet is t, the inner radius of the flexible sheet is r1, the outer radius of the flexible sheet is r2, and r2-r1≥10t.

[0014] The equation of the groove curve in the polar coordinate system is: R=k*θ, 0.05≤k≤0.2; r1 / k≤θ≤r2 / k, wherein the origin of the polar coordinate system is at the intersection of the inner circle (or outer circle) axis of the flexible sheet and the neutral plane of the flexible sheet, R is the polar radius in the polar coordinate system, k is the coefficient, and θ is the polar angle in the polar coordinate system.

[0015] Each radial support structure also includes a glue cup and a glue rod. The glue rod is fixed to the surface of the triangular back plate facing the back of the reflector. The glue cup is fixed to the end of the cone beam away from the movable plate. The glue rod is inserted into the glue cup. The gap between the glue rod and the glue cup is fixed by glue injection.

[0016] The end of the glue rod away from the cone beam is an open end, and a glue injection hole is arranged at the bottom of the open end of the glue rod, and the glue injection hole penetrates to the surface of the glue rod close to the cone beam.

[0017] The radius of the reflector is R0, and the three circular nested holes are on the same circle with a radius of R1, which is concentric with the reflector; all the bonding pads form two circles concentric with the reflector, and the radii of the two circles are R2 and R3 respectively. R0, R1, R2 and R3 satisfy:

[0018] R2=0.35R0~0.45R0

[0019] R3=0.8R0~0.9R0

[0020]

[0021] In summary, this application at least includes the following beneficial technical effects:

[0022] 1. This support structure allows large-aperture reflectors to obtain better mirror surface shape under gravity when placed at any angle between the reflector optical axis and the direction of gravity without the need for unloading structure. That is, the direction of gravity is insensitive to the reflector surface shape.

[0023] 2. This support structure sets radial supports on the neutral plane inside the reflector. Compared with setting the support structure at the radial edge of the reflector, it requires smaller design space, is more convenient for support structure design and layout, and reduces the volume and weight of the support structure.

[0024] 3. The position distribution of the 18 support points on the back plate of the reflector is conducive to the reflector obtaining a better gravity surface shape.

[0025] 4. The glue cup and glue rod are fixed by glue injection, so that the radial shrinkage stress of the glue in the glue cup and glue rod can offset each other, avoiding structural deformation due to glue shrinkage, and greatly reducing the influence of assembly stress on the surface shape of large-aperture reflectors.

[0026] 5. The flexible sheet is grooved using the equation given in this patent. The ratio of radial and axial stiffness of the flexible sheet is relatively large, which reduces the radial size and weight of the flexible sheet. When the flexible sheet has radial size space restrictions, it can provide a larger design space for the flexible sheet to move.

[0027] 6. Designing a limit structure in the normal direction (i.e., axial direction) of the flexible sheet can prevent the flexible sheet from being damaged due to excessive deformation during vibration.

[0028] 7. This support structure is a quasi-static support structure, and a large number of flexible support structures are used to reduce the impact of assembly stress and external environmental disturbances on the surface shape of the reflector. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of the whiffletree support structure mentioned in the background technology;

[0030] Figure 2 The supporting methods of large-aperture reflectors for ground-based telescopes are shown in Figure a and Figure b respectively.

[0031] Figure 3 It is a schematic diagram of the overall structure of the connection between the reflector and the reflector support structure;

[0032] Figure 4 A cross-sectional view of a reflector assembly formed after the reflector is connected to the reflector support structure at the position of the circular nesting hole;

[0033] Figure 5 Schematic diagram of one side of the circular nested hole for the reflector;

[0034] Figure 6 It is a front view of the overall structure after the reflector is connected to the reflector support structure;

[0035] Figure 7 It is the overall structural diagram of the whiffletree support structure, triangular back plate, and radial support structure;

[0036] Figure 8 for Figure 7 A cross-sectional view through the axis of the flexible sheet;

[0037] Fig. 9 It is the overall structural diagram of the whiffletree support structure and the radial support structure;

[0038] Fig.10 A cross-sectional view of the whiffletree support structure through the axis of the flexible support rod;

[0039] Fig.11 Schematic diagram of the structure of the flexible support rod, wherein the left figure is a schematic diagram of the three-dimensional structure of the flexible support rod, and the right figure is a cross-sectional view of the flexible support rod through its own axis;

[0040] Fig.12 It is a structural schematic diagram of a flexible joint hinge;

[0041] Fig.13 A partial cross-section of the whiffletree support structure

[0042] Fig.14 Schematic diagram of the structure of the triangular back plate;

[0043] Fig.15 Schematic diagram of the relative positions of three radial flexible support structures evenly distributed at 120° in the radial direction of the reflector;

[0044] Fig.16 is a cross-sectional view of a radial flexible support structure;

[0045] Fig.17 Schematic diagram of the structure of the flexible sheet, wherein the upper figure is a schematic diagram of the three-dimensional structure of the flexible sheet and the lower figure is a cross-sectional view of the flexible sheet;

[0046] Fig.18 It is a structural schematic diagram of a rubber cup;

[0047] Fig.19 It is a structural schematic diagram of the rubber rod;

[0048] Fig. 20 is a schematic diagram of the structure of the reflector;

[0049] Fig.21Schematic diagram of the structure of the reflector assembly formed by connecting the reflector and the reflector support structure at different viewing angles.

[0050] Description of the reference numerals: 1. whiffletree support structure; 2. triangular back plate; 3. radial support structure;

[0051] 11. Adhesive pad; 12. Flexible support rod; 13. Support rod rubber cup; 14. Triangular support block; 15. Flexible joint hinge; 16. Lever beam; 17. Shaft; 18. Bearing;

[0052] 21. Joint; 22. Composite beam;

[0053] 31. Nesting; 32. Flexible sheet; 33. Limiting block; 34. Movable plate; 35. Conical beam; 36. Rubber cup; 37. Rubber rod. DETAILED DESCRIPTION

[0054] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0055] The present application embodiment discloses a large-aperture reflector support structure that can adapt to gravity fields at various angles, such as Figure 3 and Fig.21 As shown, the technical solution of the support structure of the present application is to add three radial support structures on the centroid plane of the reflector based on the 18-point whiffletree bottom surface support method and the quasi-static support principle.

[0056] like Figure 3 , Figure 4 , Figure 7 and Figure 8 As shown. The main support structure is divided into three parts, one part is the whiffletree support structure 1, one part is the triangular back plate 2, and the other part is three radial support structures 3 installed on the central surface of the reflector. The whiffletree support structure 1 and the three radial support structures 3 are all installed and fixed on the triangular back plate 2. The triangular back plate 2 is then connected to the external mounting structure.

[0057] like Fig. 9 , Fig.10 and Fig.11 As shown, the Whiffletree support structure 1 is composed of three identical parts evenly distributed at 120°, each of which includes an adhesive pad 11, a flexible support rod 12, a support rod glue cup 13, a triangular support block 14, a flexible joint hinge 15, a lever beam 16, a shaft 17 and a bearing 18. Fig.13As shown. The bonding pad 11 is made of invar material, with a glue injection hole in the center, which is bonded to the reflector by glue injection, and the other side is connected to the flexible support rod 12 by screws. The flexible support rod 12 is fixed to the support rod glue cup 13 by glue injection, and the support rod glue cup 13 is connected to the triangular support block 14 by screws. Each of the three corners of the triangular support block 14 is connected to a support rod glue cup 13. A flexible joint hinge 15 is installed at the center of the triangular support block 14, as shown in FIG. Fig.12 As shown. The flexible joint hinge 15 is connected to its own local coordinate system (such as Fig.12 ) can realize the release of the rotational freedom in two directions (Rx and Ry) perpendicular to the mounting surface. The two triangular support blocks 14 are respectively mounted at the two ends of the lever beam 16 through the flexible joint hinge 15. A bearing 18 is installed in the middle of the lever beam 16 to transfer the gravity load of the reflector to the triangular back plate 2 through the shaft 17, that is, the lever beam 16 and the triangular back plate 2 are rotationally connected through the bearing 18 and the shaft 17.

[0058] like Fig.14 As shown, the triangular back plate 2 is composed of a joint 21 and a composite beam 22. The joint 21 and the composite beam 22 are bonded by epoxy adhesive.

[0059] like Fig.15 , Fig.16 and Fig.17 As shown, three radial support structures 3 are distributed at 120° relative to the center of the reflector. Each radial support structure 3 includes a nest 31, a flexible sheet 32, a limit block 33, a movable plate 34, a cone beam 35, a rubber cup 36 and a rubber rod 37. The flexible sheet 32 ​​is a key component that can realize the release of three degrees of freedom Tz, Rx and Ry. The flexible sheet 32 ​​reduces the z-direction stiffness by cutting grooves. The grooves start from the edge of the flexible sheet 32 ​​and extend in a planar spiral manner gradually approaching the center of the flexible sheet 32. The grooves are evenly distributed in the circumferential direction of the flexible sheet 32. Fig.17As shown in the upper and lower figures. The nesting 31 is bonded to the nesting hole of the reflector by epoxy glue, and the flexible sheet 32 ​​is installed on the nesting 31. The cone beam 35, the flexible sheet 32 ​​and the movable plate 34 are connected together by screws, and the limit block 33 is installed on the nesting 31. Since the rigidity of the central area of ​​the flexible sheet 32 ​​in the plane normal direction (z direction) is very small, the cone beam 35 and the movable plate 34 can be moved in the z direction. In order to prevent excessive displacement, the movable plate 34 is added between the flexible sheet 32 ​​and the limit block 33. The edge of the flexible sheet 32 ​​has a high rigidity in the z direction. The movable plate 34 can be limited in the z direction by the flexible sheet 32 ​​and the limit block 33. The lower end of the cone beam 35 is connected to the rubber cup 36 by screws, and the rubber rod 37 is embedded in the rubber cup 36, with a gap of 2 to 3 mm between them. The rubber rod 37 is screwed to the triangular back plate 2. The end of the glue rod 37 away from the cone beam 35 is an open end. A glue injection hole is set at the center of the bottom of the open end of the glue rod 37. The glue injection hole penetrates the surface of the glue rod 37 close to the cone beam 35. After the position of the reflector is adjusted, the epoxy glue is injected into the gap between the glue cup 36 and the glue cup 37 through the center glue injection hole of the glue rod 37. The glue cup 36 and the glue cup 37 are connected without screws but after the glue injection is cured. This method can reduce the assembly stress caused by screwing and allow the reflector to obtain a better surface shape. Fig.18 and Fig.19 shown.

[0060] like Fig. 20 As shown, the radius of the circular reflector is R0, and the three circular nested holes on the back of the reflector (bonded to the three radial support structures 3) have a circumferential radius of R1 respectively. Six points in the inner circle of the 18 support points are located on the circumference of the radius R2, and the 12 points in the outer circle are evenly distributed on the circumference of the radius R3.

[0061] like Figure 5 and Figure 6 As shown, in order to ensure that the reflector has good surface accuracy and that the structure of this scheme can be reasonably laid out, the reflector radius R0, the support point arrangement radius R1, R2 and R3 should satisfy the following relationship:

[0062] R2=0.35R0~0.45R0

[0063] R3=0.8R0~0.9R0

[0064]

[0065] When the optical axis of the reflector is vertical, under the action of gravity, the whiffletree support structure 1 bears the weight of the reflector, while the radial support structure 3 does not bear any load.

[0066] When the optical axis of the reflector is horizontal, under the action of gravity, the whiffletree support structure 1 does not bear any load, but the radial support structure 3 bears any load.

[0067] When the optical axis and gravity form an arbitrary angle θ, the whiffletree support structure 1 bears the component of gravity in the direction of the optical axis, while the three radial support structures 3 bear the component of gravity in the radial direction. The two supports work at the same time, realizing unloading of the reflector when placed at any angle.

[0068] The reflector support structure of the present application is compact and lightweight, and is not only easy to realize a higher gravity surface shape when the optical axis is horizontal, but also easy to realize a gravity surface shape when the optical axis is vertical. The main features of the support structure are as follows:

[0069] (1) The 18 pivot positions of the whiffletree support structure 1 and the three radial support structure positions satisfy the following relationship

[0070] R2=0.35R0~0.45R0

[0071] R3=0.8R0~0.9R0

[0072]

[0073] (2) The component of gravity acting along the optical axis relies on the bottom whiffletree support structure 1 to provide a reaction force, and the component of gravity acting in the direction perpendicular to the optical axis relies on the three radial support structures 3 to provide a reaction force.

[0074] (3) In the Whiffletree structure, a flexible joint hinge 15 is used between the lever beam 16 and the triangular support block 14. This structure is more equivalent to a real ball joint structure than other structures. The cross-flexible axis around Rx and the axis around Rx intersect at one point in space. The intersection point is the physical ball joint center, which makes it easier to calculate the position of the ball joint center.

[0075] (4) In the Whiffletree support structure 1, a support rod rubber cup 13 is used between the flexible support rod 12 and the triangular support block 14 to reduce assembly stress and improve support surface accuracy.

[0076] (5) The three confluence points of the bottom whiffletree support structure are connected together through a triangular back plate. At the same time, the three corners of the triangular back plate support structure are respectively connected to three flexible nodes supported on the centroid plane.

[0077] (6) The Whiffletree support structure 1 only constrains the reflectors Rx, Ry and Tz, and the three radial support structures 3 constrain Tx, Ty and Rz. Among them, Tx, Ty and Tz refer to the translational freedom along the three directions of X, Y and Z respectively, and Rx, Ry and Rz refer to the rotational freedom around the three directions of X, Y and Z respectively. The Z axis is the optical axis of the reflector, and the X axis and Y axis are perpendicular to the Z axis, and the X axis and Y axis are perpendicular to each other. The flexible joint hinge 15 determines the X axis and Y axis.

[0078] (7) The three radial support structures adopt a leaf spring structure. The neutral plane (the symmetry plane in the thickness direction) of the flexible sheet 32 ​​passes through the center of gravity plane of the reflector. It is required that r2-r1≥10t. Fig.17 As shown, t is the thickness of the flexible part of the flexible sheet 32, r1 is the inner radius of the flexible sheet 32, r2 is the outer radius of the flexible sheet 32, and three grooves are used to divide the leaf spring to release the z-direction degree of freedom. The polar coordinate system equations of the three groove curves are as follows (the origin of the polar coordinate system is at the intersection of the inner (or outer) axis of the flexible sheet 32 ​​and the neutral plane of the flexible sheet):

[0079] R=k*θ(0.05≤k≤0.2; r1 / k≤θ≤r2 / k)

[0080] In the range of 0.05≤k≤0.2, the radial flexible joint can obtain a higher ratio of radial stiffness to axial stiffness, which increases the design space of the flexible joint; where R is the polar radius in the polar coordinate system, k is the coefficient, and θ is the polar angle in the polar coordinate system.

[0081] (8) The three radial support structures 3 and the triangular back plate 2 are connected by glue injection to avoid screwing and generating large assembly stress due to uneven mounting surface. The glue injection method is to inject glue from the middle of the glue rod 37, allowing the glue to flow from the bottom to the axial bonding surface of the glue rod. When the glue is about to overflow from the edges of the glue cup 36, it can be ensured that the bonding surface between the glue cup and the glue rod can be evenly glued. At the same time, this structure can control the gap between the glue cup 36 and the glue rod 37, so that the stress of the glue shrinking in the circumference can offset each other, thereby avoiding structural deformation caused by glue shrinkage.

[0083] First, according to the radius R0 of the reflector, select appropriate R1 and R2, and determine the position of R3 according to R1 and R2.

[0084] Design the whiffletree support structure 1 and the triangular back plate 2. The flexible support rods 12 at the end of the whiffletree support structure 1 are all slender rods, and the length and diameter ratio of the flexible support rods is L / d≥10. Each flexible support rod 12 only provides constraint stiffness for the primary mirror in the z direction, and the stiffness of other degrees of freedom are released. In order to reduce assembly stress, the flexible support rods 12 and the support glue cups 13 are fixed by injection, and each triangular support block 14 is connected to the lever beam 16 through a flexible joint hinge 15. Release the rotational freedom, and determine the diameter of the flexible support rod, the specific size of each triangular block and the lever beam according to the positional sinking amount allowed by the primary mirror. According to the position of the three radial support structures 3. Design the specific structural forms of the three flexible sheets 32, each of which releases the three degrees of freedom of Rx, RY and TZ.

[0085] The flexible sheet 32 ​​is connected to the Invar nesting 31 on the outer circumference of the flexible sheet 32, and the Invar nesting 31 is directly bonded to the reflector at the back nesting hole with epoxy glue. The outer radius of the flexible sheet 32 ​​is r2, the inner radius is r1, and the thickness of the flexible part of the flexible sheet 32 ​​is t, r2-r1≥10t. The thickness of the flexible part is determined according to the weight of the reflector and the allowable strength of the flexible sheet material.

[0086] A glue cup 36 and a glue rod 37 are designed between the cone beam 35 and the triangular back plate 2. The structure is shown in the figure below. The glue injection hole is designed to avoid excessive assembly stress caused by tightening the screws.

[0087] This patent intends to protect the way in which the whiffletree and three-point flexible support structure constrain the freedom of the reflector, as well as the layout and form of the support structure. The specific design and advantages are as follows:

[0088] 1. The 18 pivot positions and three radial support structure positions and layouts of the whiffletree support structure 1 enable the large-aperture reflector to obtain a better mirror surface shape when subjected to gravity when the optical axis is vertical.

[0089] 2. The component of gravity acting along the optical axis relies on the bottom whiffletree support structure 1 to provide a reaction force, and the component of gravity acting in the direction perpendicular to the optical axis relies on three radial support structures 3 to provide a reaction force.

[0090] 3. In the Whiffletree structure, a flexible joint hinge 15 is used between the lever beam 16 and the triangular support block 14. This structure is more equivalent to a real ball joint structure than other structures. The axes of the cross-flexible rotation around RX and around RY intersect at one point in space, and the intersection point is the physical ball joint center, which makes it easier to calculate the position of the ball joint center.

[0091] 4. In the Whiffletree support structure 1, a support rod glue cup injection structure is used between the flexible support rod 12 and the triangular support block 14, which reduces assembly stress and improves the support surface accuracy.

[0092] 5. The three meeting points of the bottom whiffletree support structure are connected together through a triangular back plate. At the same time, the three corners of the triangular back plate support structure are respectively connected to the three flexible nodes supported on the centroid plane.

[0093] 6. Whiffletree support structure 1 only constrains the reflectors Rx, Ry and Tz, and the three radial support structures 3 constrain Tx, Ty and Rz.

[0094] 7. The three radial support structures adopt a leaf spring structure. The neutral plane of the flexible sheet 32 ​​(the symmetry plane in the thickness direction) passes through the center of gravity plane of the reflector. It is required that r2-r1≥10t. Three grooves are used to divide the leaf spring to release the z-direction degree of freedom. The equations of the three groove curves in the polar coordinate system are as follows (the origin of the polar coordinate system is the center of the radial flexible node):

[0095] R=k*θ(0.05≤k≤0.2; r1 / k≤θ≤r2 / k)

[0096] In the range of 0.05≤k≤0.2, the radial flexible joint can obtain a higher ratio of radial stiffness to axial stiffness, which increases the design space of the flexible joint.

[0097] 8. The three radial support structures 3 and the triangular back plate 2 are connected by glue injection to avoid screwing and generating large assembly stress due to uneven mounting surface. The glue injection method is to inject glue from the middle of the glue rod 37, so that the glue flows from the bottom to the axial bonding surface of the glue rod. When the glue is about to overflow from the edges of the glue cup 36, it can be ensured that the bonding surface between the glue cup and the glue rod can be evenly glued. At the same time, this structure can control the gap between the glue cup 36 and the glue rod 37, so that the stress of the glue shrinking in the circumference can offset each other, avoiding structural deformation caused by glue shrinkage.

[0098] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0099] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A large-aperture reflector support structure adapted to various angles of gravity field, connected to the back of the reflector, characterized in that: The invention comprises a triangular back plate (2), three whiffletree support structures (1) and three radial support structures (3), wherein the three whiffletree support structures (1) and the three radial support structures (3) are respectively connected to three corners of the triangular back plate (2), three circular nesting holes are provided on the back of the reflector, and the ends of the radial support structures (3) facing the reflector are bonded to the circular nesting holes, and each whiffletree support structure (1) comprises a plurality of bonding pads (11), and the bonding pads (11) are bonded to the back of the reflector by glue injection.

2. A large-aperture reflector support structure adapted to various angles of gravity fields according to claim 1, characterized in that: The whiffletree support structure (1) also includes a lever beam (16), a triangular support block (14), a support rod rubber cup (13) and a flexible support rod (12); the lever beam (16) is rotatably connected to the triangular back plate (2); the rotation axis of the lever beam (16) is in the same plane; two triangular support blocks (14) are provided; the two triangular support blocks (14) are respectively connected to the two ends of the lever beam (16) facing the surface of the reflector; each corner of the triangular support block (14) is fixedly connected to a support rod rubber cup (13); the support rod rubber cup (13) is provided with a through hole; the end of the flexible support rod (12) is inserted into the through hole; the through hole and the outside of the flexible support rod (12) are fixed by glue injection; and the bonding pad (11) is connected to one end of the flexible support rod (12) facing the back of the reflector.

3. The large-aperture reflector support structure adapted to various angles of gravity fields according to claim 3, characterized in that: The whiffletree support structure (1) further comprises a flexible joint hinge (15), the triangular support block (14) is connected to the lever beam (16) via the flexible joint hinge (15), and the flexible joint hinge (15) has two rotation axes, an x-axis and a y-axis, so that the triangular support block (14) and the lever beam (16) can realize rotational freedom in two directions around the x-axis and around the y-axis.

4. The large-aperture reflector support structure adapted to various angles of gravity fields according to claim 1, characterized in that: The three radial support structures (3) are distributed at 120 degrees relative to the center of the reflector. Each radial support structure (3) comprises a nesting (31), a flexible sheet (32), a stopper (33), a movable plate (34) and a cone beam (35). The cone beam (35) is connected to the surface of the triangular back plate (2) facing the back of the reflector. The movable plate (34) is connected to one end of the cone beam (35) away from the triangular back plate (2). The nesting (31) is bonded to the nesting hole of the reflector by epoxy glue. A limit ring is arranged on the inner side of the sleeve (31); a limit block (33) is connected to the inner side of the nest (31); and the limit block (33) is located on the side of the limit ring away from the reflective surface of the reflector; the flexible sheet (32) is installed on the inner side of the nest (31); an installation ring is provided on the edge of the flexible sheet (32); the installation ring is located between the limit ring and the limit block (33); and the movable plate (34) is located between the flexible sheet (32) and the limit block (33); and the central area of ​​the flexible sheet (32) is deformable in the direction of the plane normal.

5. The large-aperture reflector support structure adapted to various angles of gravity fields according to claim 4, characterized in that: The flexible sheet (32) is provided with at least two grooves, which start from the edge of the flexible sheet (32) and extend in a planar spiral manner gradually approaching the center of the flexible sheet (32), and the grooves are evenly distributed in the circumferential direction of the flexible sheet (32).

6. The large-aperture reflector support structure adapted to various angles of gravity fields according to claim 5, characterized in that: The thickness of the flexible part of the flexible sheet (32) is t, the inner radius of the flexible sheet (32) is r1, the outer radius of the flexible sheet (32) is r2, and r2-r1≥10t.

7. The large-aperture reflector support structure adapted to various angles of gravity fields according to claim 5, characterized in that: The equation of the slot curve in the polar coordinate system is: R=k*θ,0.05≤k≤0.2; r1 / k≤θ≤r2 / k, The origin of the polar coordinate system is located at the intersection of the inner or outer circle axis of the flexible sheet (32) and the neutral surface of the flexible sheet; R is the polar radius in the polar coordinate system, k is the coefficient, and θ is the polar angle in the polar coordinate system.

8. The large-aperture reflector support structure adapted to various angles of gravity fields according to claim 4, characterized in that: Each of the radial support structures (3) further comprises a glue cup (36) and a glue rod (37), wherein the glue rod (37) is fixed to the surface of the triangular back plate (2) facing the back of the reflector, the glue cup (36) is fixed to the end of the cone beam (35) away from the movable plate (34), the glue rod (37) is inserted into the glue cup (36), and the gap between the glue rod (37) and the glue cup (36) is fixed by glue injection.

9. The large-aperture reflector support structure adapted to various angles of gravity fields according to claim 8, characterized in that: The end of the glue rod (37) away from the cone beam (35) is an open end, and a glue injection hole is arranged at the bottom of the open end of the glue rod (37), and the glue injection hole penetrates to the surface of the glue rod (37) close to the cone beam (35).

10. The large-aperture reflector support structure adapted to various angles of gravity fields according to claim 1, characterized in that: The radius of the reflector is R0, and the three circular nested holes are on the same circle with a radius of R1, which is concentric with the reflector; all the adhesive pads (11) form two circles concentric with the reflector, and the radii of the two circles are R2 and R3 respectively, and R0, R1, R2 and R3 satisfy: R2=0.35R0~0.45R0 R3=0.8R0~0.9R0

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