Solar sail attitude adjustment actuator, solar sail assembly, and spacecraft

Abstract

The application discloses a solar sail attitude adjusting actuator, and relates to the technical field of solar sail spacecrafts, which comprises a deformation layer, wherein the deformation layer is used for being laid on the back of a solar sail, and the deformation layer can be deformed to drive the solar sail to move, so as to realize the attitude adjustment of the solar sail. The application further discloses a solar sail assembly which comprises a solar sail and the above-mentioned solar sail attitude adjusting actuator. The application further discloses a spacecraft which comprises the above-mentioned solar sail assembly. The application improves the precision of the attitude control of the solar sail, saves energy, and further improves the load that can be borne, and greatly reduces the failure rate.

Description

Technical Field

[0001] This invention relates to the field of solar sail spacecraft technology, and in particular to a solar sail attitude adjustment actuator, a solar sail assembly, and a spacecraft. Background Technology

[0002] As spacecraft travel farther and spend longer in orbit, they need to carry more propellant and energy at launch, which increases the launch mass and further increases the difficulty and cost of the launch phase.

[0003] In recent years, solar sails have attracted attention as a new type of spacecraft propulsion method. Spacecraft obtain propulsion by generating solar radiation pressure through large-area, lightweight thin-film solar sails. Solar sail propulsion technology no longer needs to rely on propellant injection and consumption, which can reduce the cost and difficulty of spacecraft launch.

[0004] However, the attitude adjustment of solar sails is currently usually controlled by traditional electric motors, for example, such as... Figure 1 As shown, it is a solar sail spacecraft structure with control surfaces. Four small triangular solar sails, which serve as control surfaces 104, are installed at the end of the structural rod 102 of the solar sail. They can rotate around the structural rod 102 under the drive of a motor. When the control surfaces 104 rotate to a certain appropriate angle, the solar pressure acting on the control surfaces 104 is used to generate the solar pressure control torque required for the three-axis attitude control of the spacecraft.

[0005] Current solar sails use conventional motors for attitude control. These motors are heavy and have several drawbacks. First, during operation, conventional motors experience significant energy losses due to electromagnetic induction and resistance, such as resistive losses, iron losses, and friction losses. These losses reduce the energy efficiency of the motors. Second, the efficiency of conventional motors varies under different loads, generally being lower at low loads and higher at full loads. Therefore, the energy efficiency of conventional motors can be affected by load variations. Third, conventional motors require an external power supply to operate, but the stability of this external power supply can also affect the energy efficiency of the motors.

[0006] Therefore, traditional motors have problems such as high failure rate, low accuracy, small load, and high energy consumption, making them unsuitable for solar sail interplanetary exploration missions with long mission cycles and high attitude control accuracy requirements. Summary of the Invention

[0007] The purpose of this invention is to provide a solar sail attitude adjustment actuator, a solar sail assembly, and a spacecraft to solve the problems existing in the prior art, improve the accuracy of solar sail attitude control, save energy, increase the load capacity, and greatly reduce the failure rate.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] The present invention provides a solar sail attitude adjustment actuator, comprising: a deformable layer, the deformable layer being laid on the back of the solar sail, and the deformable layer being deformable to drive the solar sail to move, thereby realizing the attitude adjustment of the solar sail.

[0010] Preferably, the deformable layer includes an SMA component and an SMP material layer, with the SMA component laid on at least one side of the SMP material layer; and the solar sail attitude adjustment actuator further includes a heating device, which heats the deformable layer to enable it to deform.

[0011] Preferably, the SMA component is an SMA rod, and the SMA rods are laid on both sides of the SMP material layer, and each of the SMA rods on both sides is disposed in an elastic material layer, which is laid on both sides of the SMP material layer.

[0012] Preferably, the elastic material layer is a Veroclear elastic material layer.

[0013] Preferably, the heating device includes a power supply and a heating element. The SMA rod is electrically connected to the power supply. The heating element is disposed within the SMP material layer. After the SMP material layer is heated by the heating element, its hardness decreases. When the SMA rod is energized, it deforms and causes the SMP material layer to deform. After the deformation is completed, the SMP material layer can be restored to its original state by being heated again to the transition temperature.

[0014] Preferably, the heating element is a heating wire, and the heating wire is electrically connected to the power source.

[0015] The present invention also provides a solar sail assembly, including a solar sail and a solar sail attitude adjustment actuator as described above.

[0016] Preferably, the solar sail includes a fixed shaft and multiple sail assemblies, all of which are arranged around the fixed shaft; wherein each sail assembly includes a first sail and a second sail, one side of the first sail and one side of the second sail are connected to a fixed truss, one end of the fixed truss is fixed to the fixed shaft; a movable truss is connected to the side of the first sail and the second sail away from the fixed truss, one end of the movable truss is rotatably connected to the fixed shaft.

[0017] Preferably, four sail components are provided.

[0018] The present invention also provides a spacecraft including the solar sail assembly described above.

[0019] The present invention achieves the following technical effects compared to the prior art:

[0020] In this invention, the solar sail is moved by the deformation of the deformation layer, thereby adjusting the attitude of the solar sail. This eliminates the use of traditional motors, greatly improves the accuracy of solar sail attitude control, saves energy, increases the load capacity, and significantly reduces the failure rate. Moreover, compared with the prior art which uses four triangular control surfaces to control the attitude of the solar sail, this invention increases the controllable angle range. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a solar sail spacecraft structure with control surfaces in the prior art;

[0023] Figure 1 In the middle: 101-spacecraft payload; 102-structural rod; 103-sail surface; 104-control wing surface.

[0024] Figure 2 This is a memory shape diagram of the SMA rod in an embodiment of the present invention;

[0025] Figure 3 This is a memory shape diagram of the SMP material layer in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram illustrating the deformation principle of the deformation layer in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the solar sail structure in an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the attitude adjustment of the solar sail in an embodiment of the present invention;

[0029] Figure 7 This is a Simuink circuit simulation diagram in an embodiment of the present invention.

[0030] Figures 2-7In the middle: 1-SMA rod; 2-SMP material layer; 3-fixed shaft; 4-first sail; 5-second sail; 6-fixed truss; 7-movable truss; 8-connector. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The purpose of this invention is to provide a solar sail attitude adjustment actuator, a solar sail assembly, and a spacecraft to solve the problems existing in the prior art, improve the accuracy of solar sail attitude control, save energy, increase the load capacity, and greatly reduce the failure rate.

[0033] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1

[0035] like Figures 2-4 As shown, this embodiment provides a solar sail attitude adjustment actuator, including: a deformable layer, which is used to be laid on the back of the solar sail, and the deformable layer can deform to drive the solar sail to move, thereby realizing the self-attitude adjustment of the solar sail.

[0036] In this embodiment, the solar sail is moved by the deformation of the deformation layer, thereby adjusting the attitude of the solar sail. This eliminates the use of traditional motors, greatly improves the accuracy of solar sail attitude control, saves energy, increases the load capacity, and significantly reduces the failure rate. Moreover, compared with the existing technology that uses four triangular control surfaces to control the attitude of the solar sail, this embodiment increases the controllable angle range.

[0037] In this embodiment, the deformable layer can be selected according to specific working needs. For example, the deformable layer can be a piezoelectric fiber sheet, preferably an MFC (Macro Fiber Composite) piezoelectric fiber sheet. The deformation of the piezoelectric fiber sheet is controlled by the actuator, thereby driving the solar sail to move and realizing the attitude control of the solar sail.

[0038] In this embodiment, a bidirectional deformable material, SMA-SMP, is preferably used as the deformable layer. Simultaneously, the solar sail structure is modeled using Solidworks, and the stress simulation of the solar sail is performed using Matlab and Simulink. Specifically, the deformable layer mainly includes an SMA (shape memory alloy) component and an SMP (shape memory polymer) material layer 2. The SMA component is preferably an SMA rod 1, and the SMP material layer 2 preferably has SMA rods 1 laid on both sides, forming an SMA-SMP actuator. Furthermore, the memory shape of the SMA rod 1 is U-shaped, and the memory shape of the SMP material layer 2 is rectangular. The solar sail attitude adjustment actuator also includes a heating device, and the deformable layer can deform after being heated by the heating device, such as... Figures 2-4 As shown.

[0039] In this embodiment, the heating device mainly includes a power supply and a heating element. The SMA rod 1 is electrically connected to the power supply, and the SMA rod 1 is heated by the power supply. The heating element is disposed in the SMP material layer 2 and is used to heat the SMP material layer 2. The SMP material layer 2 becomes less hard after being heated by the heating element. The SMA rod 1 deforms after being heated by the power supply, which in turn causes the SMP material layer 2, which has become less hard, to deform. After the deformation is completed, the SMP material layer can return to its original shape when heated to the transition temperature.

[0040] In this embodiment, the heating device is preferably an electric heating wire, and the electric heating wire is electrically connected to the power source.

[0041] In this embodiment, each of the SMA rods 1 on both sides is disposed within an elastic material layer, and the two elastic material layers are respectively laid on both sides of the SMP material layer 2. As a preferred embodiment, the elastic material layer is a Veroclear elastic material layer, wherein VeroClear (photosensitive resin) is a rigid, nearly colorless material with high dimensional stability, suitable for general use, detailed modeling, and visualization simulation of transparent thermoplastic materials (such as PMMA); or, other elastic material layers may be selected according to specific work needs.

[0042] In this embodiment, the SMA-SMP actuator utilizes the shape memory effect of the SMA material to achieve the driving function. The SMA rod 1 is preloaded and installed in an elastic Veroclear material layer, and is mounted on both sides of the SMP material layer 2. Simultaneously, a heating wire (preferably a resistance heating wire) is also installed in the SMP material layer 2. During deformation, the SMP material layer 2 is first heated by the heating wire and softens, changing from a glassy state (high stiffness) to a rubbery state (low stiffness). Then, the current input to the heating wire is stopped, and the SMA rod 1 is energized and heated, contracting due to its shape memory effect. The SMA rod 1 remains in the driven state until the SMP material layer 2 cools to a high-hardness glassy state. When the SMA rod 1 is heated, the surrounding Veroclear material is also heated, its hardness decreases, and it is thus compressed.

[0043] In this embodiment, the above method is used. The SMA-SMP actuator bends to the side and drives the deformation of the solar sail. After the deformation is completed, the SMP material layer 2 first stops heating and hardens. When the SMP material layer 2 is hard enough, the SMA rod 1 stops heating and the deformation is completed. At this time, due to the high rigidity of the SMP material layer 2, the solar sail attitude adjustment actuator maintains the deformed shape.

[0044] Finally, current is applied to the heating wire again to heat the SMP material layer 2 to the transition temperature, so that the SMP material layer 2 recovers its memory shape, and then it is cooled, thereby realizing the shape recovery of the solar sail attitude adjustment actuator.

[0045] In this embodiment, SMA-SMP bidirectional deformable smart material is used instead of traditional motor-driven solar sail. SMA rod 1 can be trained into a temporarily elongated shape under a combination of thermal and mechanical loads, and then contracted to restore its original shape; this is caused by the transformation between the martensitic phase at low temperature and the austenitic phase at high temperature.

[0046] The SMA-SMP actuator is printed with a rigid SMP material layer 2 and an elastic soft layer (Veroclear elastic material and SMA rods 1 within it). Shape retention and stiffness adjustment are achieved by using embedded SMP material layers 2 of varying thicknesses. Temperature in the deformation region is controlled by heating with a heating wire, transitioning it from a high-stiffness state at room temperature to a low-stiffness state at high temperature. When the SMP material layer 2 is in a low-stiffness state, the actuation of the SMA rods 1 causes large bending deformation in the deformation region. The shape memory of the SMP material layer 2 also allows it to recover its original shape at high temperatures.

[0047] This embodiment measures various properties of the SMA-SMP actuator, including bending stiffness and maximum deformation, to demonstrate the versatility of multi-material 3D printing; a finite element model was also developed to determine important actuation parameters, including shape fixation and recovery.

[0048] In this embodiment, the SMP material layer 2 can be restored to its original shape by heating to a specific transition temperature, which can be the glass transition temperature or the crystallization melting temperature of the polymer. The deformation of the SMP material layer 2 into the desired shape is achieved through a specific thermomechanical process, which typically begins above the transition temperature. While maintaining this deformed state, the SMP material layer 2 is cooled below the transition temperature; during the cooling process, the SMP material layer 2 becomes more rigid due to glassization or crystallization, thus maintaining its shape.

[0049] In this embodiment, by combining SMA and SMP, an active composite material can be manufactured that can have a large force recovery at high temperatures, maintain its deformed shape at low temperatures, recover its deformed shape, and withstand a large load. This material can be used to make bidirectional reversible actuators.

[0050] Due to the aforementioned characteristics of SMA-SMP, its use in solar sail attitude control actuators allows for the manufacture of actuators with complex shapes to meet diverse mission requirements, whereas traditional motors are subject to structural limitations. Similarly, the high energy conversion efficiency of composite materials results in a high conversion rate between mechanical and electrical energy in the actuator. Furthermore, applying SMA-SMP to solar sails leads to lighter, stronger structures, improving the overall system's operational efficiency. This embodiment also utilizes the change in the area of ​​the entire solar sail for self-attitude adjustment; a larger change area increases the controllable range of attitude changes.

[0051] In summary, the solar sail attitude adjustment actuator in this embodiment is a smart structure based on the smart material SMA-SMP. Through the bidirectional deformation function of the smart material and the three-axis attitude control, it achieves the purpose of self-attitude adjustment control of the solar sail, which greatly improves the accuracy of attitude control, saves energy, increases the load capacity, and greatly reduces the failure rate. Moreover, compared with the existing technology that uses four triangular control surfaces for attitude control, which has a smaller light-receiving area and a smaller controllable angle range, this technology can increase the range of attitude changes that can be controlled.

[0052] like Figures 6-7As shown, this embodiment also provides a solar sail assembly, including a solar sail and the solar sail attitude adjustment actuator as described above. Specifically, the solar sail includes multiple sail assemblies and a fixed shaft 3, with all the sail assemblies arranged around the fixed shaft 3. Each sail assembly includes a first sail 4 and a second sail 5, and the solar sail attitude adjustment actuator is provided on both the first sail 4 and the second sail 5. One side of the first sail 4 and one side of the second sail 5 are connected to a fixed truss 6, and one end of the fixed truss 6 is fixed to the fixed shaft 3. A movable truss 7 is connected to the side of the first sail 4 and the second sail 5 away from the fixed truss 6, and one end of the movable truss 7 is rotatably connected to the fixed shaft 3. Specifically, one end of the movable truss 7 can be rotatably connected to the fixed shaft 3 via a universal ball joint.

[0053] In this embodiment, the first sail 4 and the second sail 5 can be connected to the corresponding fixed truss 6 and movable truss 7 via connectors 8; wherein, the connectors 8 can be selected according to specific working needs, such as straps or buckles.

[0054] In this embodiment, a single sail assembly is supported by three trusses: a fixed truss 6 and two movable trusses 7. The fixed truss 6 provides support for the solar sail, while the two movable trusses 7 can bend under the drive of the SMA-SMP actuator, controlling the deflection of each part of the sail around the central fixed axis 3, thus deforming the solar sail. In this embodiment, through the coordinated deformation of multiple parts, the total area and area distribution of the solar sail in different directions can be controlled, thereby controlling the magnitude and direction of the forces and moments on the solar sail, and ultimately achieving propulsion and attitude control of the solar sail spacecraft.

[0055] In this embodiment, four sail components are preferably provided; alternatively, other numbers of sail components may be selected according to specific working needs, such as five or six sail components.

[0056] In this embodiment, the preset solar sail surface area is approximately 1200m². 3 The solar sail has a mass of approximately 30 kg and a moment of inertia of approximately 7000 kg*m. 2 Subsequently, a circuit was built in Simuink to simulate the motion of the solar sail under forces and torques. For example... Figure 7 As shown, simulation results indicate that the solar sail can rotate 22° over a period of 16 minutes, which is sufficient to control the attitude of the solar sail spacecraft in space.

[0057] This embodiment also provides a spacecraft, including the solar sail assembly described above.

[0058] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A solar sail assembly, characterized in that: The device includes a solar sail and a solar sail attitude adjustment actuator. The solar sail attitude adjustment actuator includes a deformable layer, which is laid on the back of the solar sail and can deform to drive the solar sail to move, thereby achieving attitude adjustment of the solar sail. The deformation layer includes an SMA component and an SMP material layer. The SMA component is an SMA rod, and the SMA rods are laid on both sides of the SMP material layer to form an SMA-SMP actuator. The solar sail includes a fixed shaft and multiple sail assemblies, all of which are arranged around the fixed shaft. Each sail assembly includes a first sail and a second sail. One side of the first sail and one side of the second sail are connected to a fixed truss, one end of which is fixed to the fixed shaft. A movable truss is connected to the side of the first sail and the second sail away from the fixed truss, one end of which is rotatably connected to the fixed shaft. The fixed truss provides support for the solar sail, while the two movable trusses can bend under the drive of the SMA-SMP actuator, controlling the deflection of each part of the sail around the central fixed axis to achieve the deformation of the solar sail.

2. The solar sail assembly according to claim 1, characterized in that: The solar sail attitude adjustment actuator also includes a heating device, and the deformable layer can be deformed after being heated by the heating device.

3. The solar sail assembly according to claim 2, characterized in that: The SMA rods on both sides of the SMP material layer are each disposed within an elastic material layer, and the elastic material layers are laid on both sides of the SMP material layer.

4. The solar sail assembly according to claim 3, characterized in that: The elastic material layer is a Veroclear elastic material layer.

5. The solar sail assembly according to any one of claims 2-4, characterized in that: The heating device includes a power supply and a heating element. The SMA rod is electrically connected to the power supply. The heating element is disposed within the SMP material layer. After the SMP material layer is heated by the heating element, its hardness decreases. When the SMA rod is energized, it deforms and causes the SMP material layer to deform. After the deformation is completed, the SMP material layer can be restored to its original state when it is heated to the transition temperature again.

6. The solar sail assembly according to claim 5, characterized in that: The heating element is an electric heating wire, and the electric heating wire is electrically connected to the power source.

7. The solar sail assembly according to claim 1, characterized in that: The sail assembly is provided in four parts.

8. A spacecraft, characterized in that: Includes the solar sail assembly as described in any one of claims 1-7.

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