A solar sail with enhanced stiffness and variable configuration, a spacecraft and a driving method thereof

Abstract

The present invention belongs to the field of aerospace technology, and proposes a solar sail with enhanced stiffness and variable configuration, a spacecraft and a driving method thereof, wherein a second metal layer and a first metal layer are sequentially arranged on a flexible substrate; the first metal layer and the second metal layer are made of materials with opposite deformation tendencies when heated, and the topological grid structure edge and the beam structure constitute a bimetallic beam segment; when the first metal layer and the second metal layer are electrothermally driven, the heated second metal layer produces an axial contraction tendency, while the first metal layer produces an axial elongation tendency, and the thermal mismatch effect causes the bimetallic beam segment to bend along the vertical axis; under the action of the hinge provided by the topological grid structure edge, the flexible substrate adaptively bends along the vertical axis, and multiple bimetallic beam segments can drive the flexible substrate to be reconstructed from a flat plate to a curved surface, thereby achieving the purpose of improving the bending stiffness. When increasing the area of ​​the reflective sail, no additional equipment needs to be added, thereby improving the surface quality ratio.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace technology, and in particular relates to a solar sail with enhanced stiffness and variable configuration, a spacecraft and a driving method thereof. Background Art

[0002] A solar sail spacecraft uses sunlight pressure for space travel. Unlike the photovoltaic cells in solar panels, which convert light energy into electrical energy, solar sails convert light energy into mechanical energy. While the thrust provided by sunlight pressure is minimal, in the absence of air resistance in space, it can still provide sufficient acceleration for the high-area-to-mass ratio solar sail. As a novel propulsion method that eliminates reliance on a dielectric medium, solar sail-based light pressure propulsion technology holds significant promise for deep space exploration.

[0003] The inventors discovered that the acceleration of a solar sail spacecraft is proportional to the sail's area-to-mass ratio: that is, the larger the reflective sail area and the lower the solar sail spacecraft mass, the greater the acceleration. By utilizing high reflectivity and a high area-to-mass ratio, solar sail spacecraft can achieve significant and sustained acceleration under the influence of light pressure. However, when using high area-to-mass ratios to enhance acceleration, the low bending stiffness and poor reconfigurability of high-area-to-mass ratio solar sail films often require bulky ancillary devices to improve the structure's bending stiffness and maneuverability. This bulky ancillary equipment increases the mass of the solar sail spacecraft, further hindering the solar sail spacecraft's acceleration. Existing technologies have not yet solved the problem of simultaneously increasing the reflective sail area and reducing the mass of the solar sail spacecraft. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a solar sail, a spacecraft and a driving method thereof with enhanced stiffness and variable configuration, which achieves the purpose of improving the high-surface-to-mass ratio of the solar sail without adding bulky auxiliary equipment and without affecting the quality of the solar sail spacecraft.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a solar sail with enhanced stiffness and variable configuration, which adopts the following technical solutions:

[0006] A solar sail with enhanced stiffness and variable configuration includes a flexible substrate, a second metal layer fixed on the flexible substrate, and a first metal layer fixed on the second metal layer;

[0007] The second metal layer is a topological grid structure as a whole, and the first metal layer is a plurality of independent beam structures, each beam structure is fixed on the edge of the grid in the topological grid structure; the first metal layer and the second metal layer are made of materials with opposite deformation tendencies under heat.

[0008] Furthermore, the flexible substrate is a polyimide film with aluminum plated on the surface.

[0009] Furthermore, the first metal layer is a plurality of independent rectangular beam structures.

[0010] Furthermore, the second metal layer is a metal material that shrinks when heated.

[0011] Furthermore, the first metal layer is a metal material that expands when heated.

[0012] Furthermore, the second metal layer and the first metal layer are shape memory alloys.

[0013] Furthermore, the topological grid structure of the second metal layer includes a plurality of rectangular grids, two opposite sides of the rectangular grids are fixed with the beam structure of the first metal layer, and the other two opposite sides are not fixed with the beam structure of the first metal layer.

[0014] Furthermore, the second metal layer is connected to the flexible substrate via distributed bonding points.

[0015] To achieve the above-mentioned objectives, in a second aspect, the present invention provides a spacecraft with enhanced stiffness and variable configuration, which adopts the following technical solutions:

[0016] A spacecraft with enhanced rigidity and variable configuration includes a spacecraft body and a solar sail fixed to the spacecraft body, the solar sail including a flexible substrate, a second metal layer fixed to the flexible substrate, and a first metal layer fixed to the second metal layer;

[0017] The second metal layer is a topological grid structure as a whole, and the first metal layer is a plurality of independent beam structures, each beam structure is fixed on the edge of the grid in the topological grid structure; the first metal layer and the second metal layer are made of materials with opposite deformation tendencies under heat.

[0018] To achieve the above objectives, in a third aspect, the present invention further provides a method for driving a spacecraft with enhanced stiffness and variable configuration, which employs the following technical solutions:

[0019] A method for driving a spacecraft with enhanced stiffness and variable configuration, using the spacecraft with enhanced stiffness and variable configuration as described in the second aspect, comprising:

[0020] The topological grid structure edges and beam structure constitute bimetallic beam segments. The first metal layer and the second metal layer are electrothermally driven, causing the second metal layer to shrink in the axial direction and the first metal layer to stretch in the axial direction. The flexible substrate adaptively bends along the vertical axis, and multiple bimetallic beam segments drive the flexible substrate to reconstruct from a flat plate into a curved surface.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. In the present invention, a second metal layer having a topological grid structure and a first metal layer including multiple beam structures are sequentially arranged on a flexible substrate. The first and second metal layers are made of materials with opposite deformation tendencies when heated, and the edges of the topological grid structure and the beam structures constitute bimetallic beam segments. When the first and second metal layers are electrothermally driven, the heated second metal layer tends to contract in the axial direction, while the first metal layer tends to extend in the axial direction. The thermal mismatch effect causes the bimetallic beam segments to bend along the vertical axis. Under the action of the hinges provided by the edges of the topological grid structure, the flexible substrate adaptively bends along the vertical axis. The multiple bimetallic beam segments can drive the flexible substrate to reshape from a flat surface to a curved surface, thereby achieving the purpose of improving bending stiffness. When increasing the area of ​​the reflective sail, no additional equipment is required, thereby improving the surface-to-weight ratio.

[0023] 2. In response to the common problems of low bending stiffness and poor controllable reconfiguration capability in current high-area-to-mass ratio solar sails, the present invention proposes a new modular design solution that meets the high-area-to-mass ratio requirements of chip-level solar sails. A mesh two-dimensional topological microstructure is superimposed on the underlying basis to meet the lightweight requirements. The deployable module and the reconfiguration module can be controlled separately, and the intermediate mesh two-dimensional topological microstructure is shared by the two modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the specification of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments and descriptions of this embodiment are used to explain this embodiment and do not constitute an improper limitation on this embodiment.

[0025] Figure 1 Schematic diagram of the structure of the spacecraft in Example 1 and Example 2 of the present invention;

[0026] Figure 2 For Example 1 of the present invention Figure 1 Enlarged view of part O in the middle;

[0027] Figure 3 This is a schematic diagram of the solar sail structure of Example 1 of the present invention;

[0028] Figure 4 Schematic diagram of the solar sail structure in the coordinate system of Example 1 of the present invention;

[0029] Figure 5 For Example 1 of the present invention Figure 3 Expandable module corresponding to the middle AA section;

[0030] Figure 6 For Example 1 of the present invention Figure 3 The unfolding effect of the expandable module corresponding to the middle AA section;

[0031] Figure 7 For Example 1 of the present invention Figure 3 The unfolding effect of the expandable module corresponding to the middle BB section;

[0032] Figure 8 Schematic diagram of the solar sail structure in the coordinate system of Example 1 of the present invention;

[0033] Figure 9 For Example 1 of the present invention Figure 8 Reconstruction module corresponding to the middle CC section;

[0034] Figure 10 For Example 1 of the present invention Figure 8 The reconstruction effect of the reconstructed module corresponding to the CC section;

[0035] Among them, 1. first metal layer; 2. second metal layer; 3. flexible substrate; 4. spacecraft body; 5. bonding point. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0037] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0038] Example 1:

[0039] like Figure 1 and Figure 2 As shown, this embodiment provides a solar sail with enhanced stiffness and variable configuration, comprising a flexible substrate 3, a second metal layer 2 fixed on the flexible substrate 3, and a first metal layer 1 fixed on the second metal layer 2;

[0040] The second metal layer 2 is a topological grid structure as a whole, and the first metal layer 1 is a plurality of independent beam structures, each beam structure is fixed on the edge of the grid in the topological grid structure; the first metal layer 1 and the second metal layer 2 are made of materials with opposite deformation tendencies under heat.

[0041] Specifically, this embodiment employs a stacked design of two topological microstructures, a bottom layer and an upper layer. Optionally, the upper two-layer topological microstructure is electrothermally driven. The bottom layer is the flexible substrate 3, which has a low equivalent density and equivalent thickness. The two-layer topological microstructure of the solar sail's upper layer is made of two materials with opposite thermal deformation tendencies. The topological grid structure edges and the beam structure constitute bimetallic beam segments. When the first metal layer 1 and the second metal layer 2 are electrothermally driven, the heated second metal layer 2 tends to contract in the axial direction, while the first metal layer 1 tends to elongate in the axial direction. The thermal mismatch effect causes the bimetallic beam segments to bend along the vertical axis. Under the action of the hinges provided by the topological grid structure edges, the flexible substrate 3 adaptively bends along the vertical axis. Multiple bimetallic beam segments can drive the flexible substrate 3 to reshape from a flat surface to a curved surface, thereby achieving the purpose of improving bending stiffness. When increasing the reflective sail area, no additional equipment is required, thereby improving the surface-to-quality ratio.

[0042] The solar sail in this embodiment can be applied to chip-level solar sail spacecraft. Research is carried out from a microscopic perspective. In response to the urgent demand for high surface-to-mass ratio of solar sails, combined with the problems of low bending stiffness and poor controllable reconfiguration capability of thin film structures in the design of high surface-to-mass ratio solar sails, a new solar sail structure design and drive scheme is proposed, providing technical support for the design of the next generation of chip-level solar sails.

[0043] The most important characteristic parameters of a deployable microstructure are equivalent density and equivalent thickness. The smaller these two parameters are, the higher the structural area-to-mass ratio is. Therefore, in this embodiment, a polyimide film (PI film) with an aluminum coating on the surface can be used as the flexible substrate 3. Other materials with low equivalent density can also be used. Optionally, the thickness of the aluminum coating on the surface is 20 nm, and the thickness of the polyimide film is 2 to 7.5 μm.

[0044] In order to reduce the equivalent thickness, the upper metal layer 1 and the lower metal layer 2 are designed as a topological grid structure or distribution, which helps to reduce their equivalent thickness. The thickness of the beam unit in the two-dimensional topological microstructure can reach more than ten microns, thereby improving the structural reliability.

[0045] The first metal layer 1 can be a plurality of independent rectangular beam structures, arranged in a topological grid pattern according to the second metal layer 2 and connected to the second metal layer 2. The second metal layer 2 can be a topological grid structure with an outer contour consistent with the flexible substrate 3. The second metal layer 2 can be connected to the flexible substrate 3 via distributed bonding points 5. The topological grid helps reduce its equivalent thickness. The thickness of the beam unit in the two-dimensional topological microstructure can reach more than ten microns, improving the structural reliability. Considering the sufficient power guarantee of the solar sail and the need for reconstruction of large deformations, the above-mentioned two-dimensional topological microstructure can be based on electrothermal drive.

[0046] To improve the efficiency of electrothermal driving, the second metal layer 2 can be made of a metal material that shrinks when heated, and the first metal layer 1 can be made of a metal material that expands when heated. Composite driving based on thermal mismatch effect and shape memory effect can be achieved through shape memory alloy.

[0047] This embodiment adopts a modular design concept. While ensuring a high surface-to-weight ratio, expandable modules and reconfigurable modules are added. Specifically, the expandable modules are the second metal layer 2 and the first metal layer 1. Under electrothermal drive, the two-layer topological microstructure of the second metal layer 2 and the first metal layer 1 produce two different deformation trends of contraction and extension, thereby generating bending along a certain direction. After the integration of multiple expandable modules, they can drive the flexible substrate 3 to reconfigure from a flat surface to a curved surface, thereby improving the bending stiffness of the structure. To achieve controllable reconfiguration of the microstructure, a reconfiguration module with the opposite bending direction is proposed. The reconfiguration module is the flexible substrate 3 and the second metal layer 2. Under electrothermal drive, the middle topological microstructure of the second metal layer 2 and the flexible substrate 3 produce bending, causing the microstructure to undergo a reconstruction effect opposite to the direction of the expansion mechanism.

[0048] To improve scalability and reconfigurability, optionally, the topological grid structure of the second metal layer 2 includes multiple rectangular grids, and the beam structure of the first metal layer 1 is fixed on two opposite sides of the rectangular grid, while the beam structure of the first metal layer 1 is not fixed on the other two opposite sides.

[0049] Specifically, such as Figure 3 and Figure 4 As shown, in order to improve the bending stiffness of the microstructure around the x-axis, the deployable module is designed along the direction parallel to the x-axis. The deformation effect of a single deployable module is shown in Figure 5 As shown, the deformation effect of the integrated multi-expandable module is as follows Figure 6The controllable deployment mechanism of the expandable module is as follows: the first metal layer 1 and the second metal layer 2 operate under electrothermal drive. The heated second metal layer 2 contracts in the x-axis direction, while the first metal layer 1 extends in the same direction. This thermal mismatch effect causes the bimetallic beam segment to bend upward about the y-axis. The hinge provided by the single metal beam causes the flexible substrate 3 to adaptively bend upward about the y-axis. The integration of multiple expandable modules can drive the flexible substrate 3 to reshape from a flat surface to a curved surface, thereby improving the bending stiffness of the structure. In order to achieve controllable reconfiguration of the microstructure, a bending scheme around the x-axis is proposed, and a reconfigurable module is designed along the direction parallel to the y-axis; the controllable reconfiguration mechanism of the reconfiguration module is as follows: the second metal layer 2 and the flexible substrate 3 work under electrothermal drive, the second metal layer 2 shrinks when heated, and the flexible substrate 3 expands when heated, causing the microstructure to undergo controllable reconfiguration around the x-axis; it should be pointed out that the stiffness enhancement effect produced by the expandable module will partially inhibit the controllable reconfiguration ability of the microstructure. The interaction between the two can be predicted and evaluated through theoretical analysis and experiments to optimize the design scheme of the high aspect ratio expandable microstructure.

[0050] Example 2:

[0051] like Figure 2 As shown, this embodiment provides a spacecraft with enhanced stiffness and variable configuration, including a spacecraft body 4 and a solar sail fixed to the spacecraft body 4. The spacecraft body 4 can be a chip-level spacecraft, around which the solar sail is fixed; the solar sail includes a flexible substrate 3, a second metal layer 2 fixed on the flexible substrate 3, and a first metal layer 1 fixed on the second metal layer 2;

[0052] The second metal layer 2 is a topological grid structure as a whole, and the first metal layer 1 is a plurality of independent beam structures, each beam structure is fixed on the edge of the grid in the topological grid structure; the first metal layer 1 and the second metal layer 2 are made of materials with opposite deformation tendencies under heat.

[0053] The solar sail in this embodiment has all the structural features and functions of the solar sail in Example 1, which will not be described in detail here.

[0054] Example 3:

[0055] This embodiment provides a method for driving a spacecraft with enhanced stiffness and variable configuration, using the spacecraft with enhanced stiffness and variable configuration as described in Example 1, including:

[0056] The topological grid structure edges and beam structures constitute bimetallic beam segments. The first metal layer 1 and the second metal layer 2 are electrothermally driven, causing the second metal layer 2 to shrink in the axial direction and the first metal layer 1 to stretch in the axial direction. The flexible substrate 3 adaptively bends along the vertical axis, and multiple bimetallic beam segments drive the flexible substrate to reconstruct from a flat plate into a curved surface.

[0057] The above description is merely a preferred embodiment of this embodiment and is not intended to limit this embodiment. Those skilled in the art will readily appreciate that this embodiment may be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this embodiment shall be within the scope of protection of this embodiment.

Claims

1. A solar sail with enhanced stiffness and variable configuration, characterized in that: The invention comprises a flexible substrate, a second metal layer fixed on the flexible substrate, and a first metal layer fixed on the second metal layer; The second metal layer is a topological grid structure as a whole, and the first metal layer is a plurality of independent beam structures, each beam structure is fixed to an edge of a grid in the topological grid structure; the first metal layer and the second metal layer are made of materials with opposite deformation tendencies under heat; The flexible substrate is a polyimide film with an aluminum-plated surface; the polyimide film with an aluminum-plated surface is trapezoidal; The topological grid structure edge and the beam structure constitute a bimetallic beam segment. Under the action of the hinge provided by the topological grid structure edge, the flexible substrate adaptively bends along the vertical axis. Multiple bimetallic beam segments can drive the flexible substrate to reconstruct from a flat plate to a curved surface.

2. A solar sail with enhanced stiffness and variable configuration according to claim 1, characterized in that: The first metal layer is a plurality of independent rectangular beam structures.

3. The solar sail with enhanced stiffness and variable configuration according to claim 1, characterized in that: The second metal layer is a metal material that shrinks when heated.

4. The solar sail with enhanced stiffness and variable configuration according to claim 1, characterized in that: The first metal layer is a metal material that expands when heated.

5. The solar sail with enhanced stiffness and variable configuration according to claim 1, characterized in that: The second metal layer and the first metal layer are shape memory alloys.

6. The solar sail with enhanced stiffness and variable configuration according to claim 1, characterized in that: The topological grid structure of the second metal layer includes a plurality of rectangular grids, two opposite sides of the rectangular grid are fixed with the beam structure of the first metal layer, and the other two opposite sides are not fixed with the beam structure of the first metal layer.

7. The solar sail with enhanced stiffness and variable configuration according to claim 1, characterized in that: The second metal layer is connected to the flexible substrate via distributed bonding points.

8. A spacecraft with enhanced stiffness and variable configuration, comprising a spacecraft body and a solar sail fixed to the spacecraft body, characterized in that: The solar sail includes a flexible substrate, a second metal layer fixed on the flexible substrate, and a first metal layer fixed on the second metal layer; The second metal layer is a topological grid structure as a whole, and the first metal layer is a plurality of independent beam structures, each beam structure is fixed on the edge of the grid in the topological grid structure; the first metal layer and the second metal layer are made of materials with opposite deformation tendencies under heat.

9. A method for driving a spacecraft with enhanced stiffness and variable configuration, characterized in that: A spacecraft with enhanced stiffness and variable configuration as claimed in claim 8, comprising: The topological grid structure edges and beam structure constitute bimetallic beam segments. The first metal layer and the second metal layer are electrothermally driven, causing the second metal layer to shrink in the axial direction and the first metal layer to stretch in the axial direction. The flexible substrate adaptively bends along the vertical axis, and multiple bimetallic beam segments drive the flexible substrate to reconstruct from a flat plate into a curved surface.

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