Carbon fiber based solar sail flexible drive structure on spacecraft and control method thereof

Abstract

The application discloses a kind of solar sail flexible drive structure based on carbon fiber on spacecraft and its control method.The flexible drive structure includes composite fiber, fixed unit and electric control unit;Composite fiber has initial twist, including carbon fiber tows and polymer, polymer includes PDMS, the space between adjacent monofilament is completely filled by polymer;Fixed unit respectively bundles and fixes two ends of multiple composite fibers into one with solar sail and spacecraft transmission connection;Electric control unit is electrically connected with two ends of fiber respectively.The application utilizes the characteristics of self-conducting, high driving force, high driving capacity, high cycle life and high environmental stability of CF / PDMS composite fiber, overcomes the problems of small driving force, low driving capacity and difficulty in adapting to outer space environment of existing artificial muscle fiber, accurately controls driving capacity and driving force by controlling voltage and power-on time, and provides a more optimal solution for the driving of solar sail of spacecraft.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and in particular to a flexible drive structure for carbon fiber-based solar panels on spacecraft and its control method. Background Technology

[0002] Most spacecraft and instruments rely on electricity to operate. With the development of aerospace and deep space exploration technologies, a continuous power supply is a critical issue in space research. Solar energy is a widely available and readily accessible energy source for spacecraft, which can be converted into electricity using solar panels. The Solar Array Drive Assembly (SADA) is a crucial component of spacecraft such as lunar rovers, satellites, space stations, spacecraft, interplanetary probes, and space telescopes, significantly impacting their energy efficiency and overall performance. It comprises two parts: the Solar Array Drive Mechanism (SADM) and the Solar Array Drive Electronics (SADE). The SADM primarily drives the solar panels to orient themselves towards the sun, ensuring maximum solar energy capture efficiency and providing power. Common drive methods include:

[0003] Motor drive: This is the most common method, using stepper or DC motors. Its advantages include high reliability, high control precision, and mature technology. However, it has a complex and bulky structure, increasing the space and energy consumption of spacecraft.

[0004] Spring-driven: The satellite solar panel is secured with a fusible cable tie. When the panel deploys, the fusible cable tie is burned off by heating a resistance wire, and the panel deploys under the action of a spring. However, the driving force is difficult to control, and collisions are prone to occur at the moment the mechanism finishes deploying, making the entire deployment process inconvenient to control. Furthermore, the drive is unidirectional; it can only deploy, not retract.

[0005] Air-driven: This method uses gas pressure to drive the rotation of the sail, providing large torque and force. The system is simple, but it is limited by air pressure, making it difficult to continuously supply air in the vacuum environment of space, and the control precision is low.

[0006] Smart material-driven: Smart materials change shape (e.g., length) when subjected to external stimuli (such as temperature changes or electric fields), thereby driving the solar panel. It possesses advantages such as lightweight, high flexibility, simple structure, and convenient integrated design, representing an important future development direction in this field.

[0007] Fiber-driven smart materials have attracted widespread attention in aerospace, flexible robotics, and human-computer interaction fields due to their advantages of good directional deformation, light weight, and ease of weaving and assembly. Commonly used materials include shape memory alloys (SMA), conductive polymer fibers, carbon nanotube fibers, and liquid crystal elastomers. Composite fibers, as structural functional materials, have become a research hotspot in the aerospace field in recent years. They are often composed of carbon fibers and polymer matrices (such as epoxy resins), and their excellent properties such as light weight, high strength, and high modulus can replace traditional metal materials, reducing the energy consumption of spacecraft.

[0008] Artificial muscle fibers, as a typical representative of smart materials, are expected to be widely used in spacecraft propulsion. However, current artificial muscle fibers still have various problems, making it difficult to meet the application requirements of spacecraft. Specifically, one type of artificial muscle fiber, represented by carbon nanotube fibers, has advantages such as being lightweight and having inherent electrical conductivity, but its high cost, limited production, and performance stability need to be improved, making it unsuitable for driving large solar panels. Another type of artificial muscle fiber, represented by polymer composite fibers, has the advantage of high driving force, but polymer fibers cannot achieve electrical conductivity and electrothermal energy conversion on their own, and usually rely on the addition of conductive components to achieve electrical actuation. In addition, although liquid crystal elastomer composite fibers can produce large driving deformation, the driving force is insufficient, and the material properties are sensitive to temperature, humidity, and radiation, which greatly limits their application in the space environment.

[0009] It is evident that, unlike propulsion in Earth's environment, applying artificial muscle fibers to solar panel propulsion in space is no easy task, requiring the fulfillment of various stringent conditions, and existing artificial muscle fibers are difficult to apply. Summary of the Invention

[0010] To address the shortcomings of existing technologies, the present invention aims to provide a flexible drive structure for carbon fiber-based solar panels on spacecraft and its control method.

[0011] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0012] In a first aspect, the present invention provides a flexible drive structure for a solar panel, used to drive the movement of a solar panel on a spacecraft, comprising composite fibers, a fixing unit and an electronic control unit.

[0013] The composite fiber has an initial twist and includes carbon fiber bundles and a polymer, including PDMS. Adjacent carbon fiber monofilaments are uniformly coated with the elastic polymer to form a stress buffer and mechanical protection layer, which makes the composite fiber flexible.

[0014] The fixing unit is disposed at both ends of the composite fiber, and the two ends of the multiple composite fibers are respectively bundled and fixed into one unit, and the fixing unit at both ends is respectively connected to the solar panel and the spacecraft transmission.

[0015] The electronic control unit is connected to the carbon fiber bundles at both ends of the composite fiber and is used to apply voltage to the carbon fiber bundles.

[0016] Secondly, the present invention also provides a control method for the above-mentioned flexible drive structure, comprising:

[0017] The electrical control unit applies voltage to the carbon fiber bundles in the composite fiber, and the composite fiber is heated by the Joule heating effect of the carbon fiber bundles. Axial contraction is achieved by untwisting caused by radial expansion. The solar panel is driven to flip by the tendency of the composite fiber contraction through the fixing unit.

[0018] The angle at which the solar panel flips is adjusted by changing the applied voltage and / or the duration of the energization.

[0019] Thirdly, the present invention also provides a spacecraft comprising the aforementioned flexible actuation structure.

[0020] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention include at least the following:

[0021] The flexible drive structure provided by this invention utilizes the self-conductivity, high driving force, high driving quantity, high cycle life, and high environmental stability of CF / PDMS composite fibers to overcome the problems of low driving force, low driving quantity, and difficulty in adapting to the outer space environment of various existing artificial muscle fibers. By controlling the voltage or the energizing time, the driving quantity and driving force can be precisely controlled, providing a better solution for the drive of solar panels in spacecraft.

[0022] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the state of composite fibers provided in a typical embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the composition and structure of a flexible drive structure provided in a typical embodiment of the present invention;

[0025] Figure 3This is a test graph of the temperature rise curve of composite fiber under different voltages provided in a typical embodiment of the present invention;

[0026] Figure 4 This is a typical embodiment of the present invention, showing the test diagrams of the driving quantity and driving force of the composite fiber under different voltages.

[0027] Figure 5 This is a 1000-cycle stability test diagram of the driving quantity and driving force provided in a typical embodiment of the present invention;

[0028] Figure 6 This is a photograph of a simulated spacecraft provided in a typical embodiment of the present invention;

[0029] Figure 7 This is a photograph of a simulated spacecraft's propulsion process provided in a typical embodiment of the present invention;

[0030] Figure 8a This is a micrograph of the cross-sectional structure of the composite fiber provided in a typical comparative case of the present invention;

[0031] Figure 8b This is a micrograph of the cross-sectional structure of the composite fiber provided in a typical embodiment of the present invention. Detailed Implementation

[0032] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0034] See Figure 1 and Figure 2 As shown, this embodiment of the invention provides a flexible drive structure for a solar panel, used to drive the movement of a solar panel on a spacecraft. It includes composite fibers, fixing units, and an electronic control unit. The composite fibers have an initial twist and comprise carbon fiber bundles and a polymer, including PDMS. Adjacent carbon fiber monofilaments are uniformly coated with the elastic polymer to form a stress buffer and mechanical protective layer, giving the composite carbon fiber a certain degree of flexibility. The fixing units are located at both ends of the composite fibers, bundling and fixing the two ends of multiple composite fibers together. The fixing units at both ends are respectively connected to the solar panel and the spacecraft for transmission. The electronic control unit is connected to the carbon fiber bundles at both ends of the composite fibers and is used to apply voltage to the carbon fiber bundles.

[0035] Based on the above technical solution, this invention mainly addresses the requirements of SADA (Solar Adaptive Technology) for drive devices, such as high precision, high reliability, durability, low power consumption, high output force, controllable start / stop, and lightweight design. A flexible conductive composite fiber material, CF / PDMS composite fiber, is selected. It is uniformly composited with carbon fiber and polydimethylsiloxane. After successful assembly, it is applied to the SADA model, and high-precision, high-durability, and controllable control of the solar panel can be achieved through simple installation.

[0036] A key feature of the CF / PDMS composite fiber used in this invention is that PDMS is fully filled in the space between the carbon fiber monofilaments, forming a stress dispersion and buffer layer, which overcomes the brittle fracture of the carbon fiber and gives it good flexibility. This allows it to form a helical structure through twisting, and then achieve drive through Joule heat stimulation.

[0037] In order to form composite fibers with the above-mentioned structural characteristics, the specific embodiment of the present invention adopts a method of multiple impregnation to fill the interior of the carbon fiber bundle with PDMS solution or pure PDMS. Different PDMS concentration gradients and capillary roller pressing devices are set during impregnation, which is something that cannot be achieved by simple impregnation methods (usually simple impregnation is difficult to make PDMS fully and uniformly coat each carbon fiber bundle filament).

[0038] Specific methods for preparing composite fibers may include:

[0039] First, carbon fiber bundles are impregnated in a diluted PDMS solution (e.g., a PDMS:diluent mass ratio of 2:1) to allow the diluted PDMS to penetrate between the monofilaments. Then, after one roll pressing, the preliminarily composite fibers are impregnated in pure PDMS. After a second extrusion and roll pressing, the fibers are heat-treated (e.g., 155–185°C, 0.5–1 min) to solidify them, thus obtaining the composite fibers. After the second roll pressing, the impregnation-roll pressing process can be repeated multiple times, followed by heat treatment.

[0040] Of course, the above method is an exemplary method used by the present invention to achieve uniform composite. If those skilled in the art obtain composite fibers with the same structural characteristics by using other methods different from the above method, they can also apply them to the solar panel drive of spacecraft and achieve the same technical effect.

[0041] Regarding the specific structural features, in some embodiments, when the composite fiber is at the initial twist, the composite fiber is in an overtwisted state and has a helical structure.

[0042] In some embodiments, the initial twist value is 2000–2300 turns / m. However, it is not limited to this; the above range is merely a commonly used range for exemplary preparations.

[0043] In some embodiments, the diameter of the composite fiber is 0.5 to 1 mm. However, it is not limited to this; the above range is merely a commonly used range for exemplary preparation.

[0044] In some embodiments, the diameter of the helical structure is 1–3 mm and the pitch is 0.3–0.6 mm. However, it is not limited to these; the above ranges are merely common ranges used in exemplary fabrication.

[0045] In some embodiments, the number of carbon fiber filaments in the carbon fiber bundle is typically 1,000-10,000. However, it is not limited to this; the above range is merely a commonly used range for exemplary preparations.

[0046] In some implementations, the number of composite fibers driven to any of the solar panels is typically 5-100. The specific number is not limited to this and can be adjusted based on the required driving force.

[0047] Furthermore, regarding specific connection structures, in some implementations, the solar panel is connected to the main structure of the spacecraft by a hinge, with both ends of the composite fiber fixed to the surfaces of the solar panel and the main structure respectively by the fixing unit, and the hinge point is not located on the extension line of the composite fiber.

[0048] In some implementations, in order to improve conductivity, reduce contact resistance, reduce power consumption, and make the heat generation of the multiple composite fibers approximately equal, the polymer at both ends of the composite fibers is removed to expose the carbon fiber monofilaments; the electrodes of the electrical control unit are electrically connected to the exposed carbon fiber monofilaments through cured metal conductive adhesive.

[0049] Correspondingly, a second aspect of the present invention also provides a control method for the flexible drive structure provided in any of the above embodiments, which includes the following steps:

[0050] A voltage is applied to the carbon fiber bundles in the composite fiber by an electronic control unit. Through the excellent Joule heating effect of the carbon fiber bundles, electrical energy is conveniently and quickly converted into heat energy, causing the composite fiber to heat up rapidly. This causes the spiral composite fiber to untwist due to radial expansion and achieve axial contraction. The solar panel is then driven to flip by the tendency of the composite fiber to contract through a fixing unit. The angle of the solar panel flipping can be adjusted by adjusting the applied voltage and / or the duration of the energization.

[0051] In practical applications, for example, when the intensity of sunlight increases to the power generation threshold, the electricity generated by the solar panels causes the spacecraft's propellers to rotate. By adjusting the angle of the solar panels, the amount of power generated can be controlled, thereby controlling the start and stop of the spacecraft's propellers.

[0052] Of course, the application is not limited to propellers that drive spacecraft. This is just a typical example. In other applications, the electricity generated by solar panels can be adjusted to drive other components, such as robotic arms, power units, computers, communication modules, and so on.

[0053] In some embodiments, the voltage is 1–7V. However, it is not limited to this; the above range is merely a commonly used range for exemplary fabrication.

[0054] As a further application of the above technical solution, a third aspect of the present invention also provides a spacecraft that includes the flexible drive structure provided in any of the above embodiments.

[0055] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0056] Example 1

[0057] In this embodiment, the high-performance flexible conductive driveable composite fiber is obtained by impregnating commercially available 1K carbon fiber tow with polydimethylsiloxane, followed by curing to obtain CF / PDMS composite helical carbon fiber. Please refer to [link to relevant documentation]. Figure 1 As shown, the specific preparation steps are as follows:

[0058] Step (1): Preparation of PDMS solution: Mix silicone rubber resin, curing agent, and non-polar solvent ethyl acetate in a 2:1 ratio, stir, remove air bubbles, and prepare a diluted silicone rubber resin solution, which becomes a diluted PDMS solution. The solution without diluent is a pure PDMS solution.

[0059] Step (2): 1K carbon fiber tow is introduced into a diluted PDMS solution for the first impregnation and then pulled out from the die. Using a low-viscosity diluted PDMS solution helps it penetrate the interior of the carbon fiber tow. The main purpose of the first impregnation is to wet the fiber bundle so that pure PDMS can be more easily impregnated into it later. The carbon fiber tow is passed around the first roller, and excess PDMS on the surface of the tow is squeezed into the interior of the fiber bundle through the squeezing action between the fiber bundle and the roller, achieving the first homogenization. Then, the fiber bundle is introduced into the pure PDMS solution for the second impregnation and pulled out from the die. The wetted carbon fiber tow continues to be capillarily homogenized by passing it through the second roller. Finally, the wetted tow is introduced into the pure PDMS solution for the third impregnation and pulled out from the die, ensuring that the PDMS solution is evenly distributed throughout the carbon fiber tow.

[0060] Step (3): The fiber bundle is cured in an oven at 180°C for about 0.5 min and collected on a spool at a certain speed. The preparation speed of CF / PDMS composite fiber is about 30 m / h.

[0061] Step (4): The cured CF / PDMS composite fiber is made into a CF / PDMS composite fiber with a uniform helical structure by inserting twist, which has good flexibility.

[0062] Due to the Joule heating effect of carbon fibers, the temperature of the spiral composite fiber rises rapidly after an electric voltage is applied, resulting in... Figure 3 As shown, this causes PDMS to expand radially, leading to untwisting and shrinkage of the helical composite fiber. The helical composite fiber obtained in step 3 can achieve excellent and different driving forces and driving amounts under different voltages, such as... Figure 4 As shown, under a voltage of 0–10N, the driving quantity can be controllably adjusted within the range of 0–40%, and the driving force can be controllably adjusted within the range of 0–2N. Figure 5 As shown, the driving quantity and driving force remain stable and do not decay during the 1000-cycle test.

[0063] The test results above show that the composite fiber of the present invention can maintain high cycle stability in terms of output strain and output force, which is the basis for designing a controllable flexible drive device for solar panels.

[0064] Example 2

[0065] This embodiment illustrates the process of fabricating a drive structure for a simulated spacecraft solar panel using the CF / PDMS composite fiber provided in the above embodiment, as detailed below.

[0066] Step 1:

[0067] One end of the CF / PDMS composite fiber is fixed, and a certain load is suspended from the other end. A wire is used to connect the lower end to a support to prevent untwisting. A motor is used to twist the composite fiber, and the composite fiber will form a spiral composite fiber after obtaining a certain twist.

[0068] Step 2:

[0069] Remove the PDMS from both ends of the CF / PDMS spiral composite fiber from step 1, apply silver paste to reduce the fiber's contact resistance, and then dry the silver paste.

[0070] Step 3:

[0071] Connect silver wires to both ends (A and B) of each CF / PDMS spiral composite fiber, and fix both ends to the template. Place three spiral composite fibers side-by-side on each template. Combine the silver wires at ends A and B of each of the three composite fibers on each template. Connect all the silver wires at ends A to the positive terminal of the power supply, and all the silver wires at ends B to the negative terminal of the power supply.

[0072] Step 4:

[0073] In step 3, two templates containing the spiral composite fiber were placed on the left and right sides of the space station model, respectively. One end was fixed to the space station model, and the other end was fixed to the solar panel. Figure 6 As shown. Of course, this embodiment is mainly for simulation experiments. The counteracting motion tendency of the solar panel (the motion tendency opposite to the contraction drive direction of the composite fiber) is provided by Earth's gravity. However, in outer space, although there may be no gravity, in practical applications, the counteracting force can be provided by elastic components, or by using the gravity of other planets.

[0074] Example 3

[0075] like Figure 7 As shown, in the initial state, the solar panels do not generate electricity due to insufficient sunlight, and the propellers in front of the space station are stationary. After power is applied, by adjusting the voltage and duration of the power supply, the spiral composite fibers shrink by about 20%, causing the solar panel to rotate about 20°. At this point, the solar panel captures more light energy, and the generated electricity causes the propellers to rotate rapidly. When the power is turned off, the CF / PDMS spiral composite fibers return to their original length, the solar panel rotates in the opposite direction by about 20°, returning to the initial position where there was insufficient sunlight, and the propellers stop rotating due to the power failure.

[0076] Due to the excellent cycle stability of CF / PDMS helical composite fibers, their performance can be repeatedly driven without degradation in actual operation. This demonstrates the potential of CF / PDMS helical composite fibers as control and drive devices in solar panel drive systems and other space structures.

[0077] The advantage of the driving method in this embodiment is that:

[0078] 1) Compared with motor drive, CF / PDMS spiral composite fiber is used as the drive device, which is lightweight, flexible and saves a lot of space and energy consumption.

[0079] 2) It can operate at low voltage and the driving quantity and driving force can be precisely controlled by controlling the voltage or the power-on time.

[0080] 3) Compared with other polymer fibers, carbon fiber itself has excellent electrothermal properties, making it an ideal material for electrothermal drive. It does not require the addition of other conductive components, has better cost and stability than carbon nanotube fibers, and has a greater driving force than liquid crystal elastomer fibers.

[0081] 4) This drive unit has advantages such as high precision, high reliability, durability, low power consumption, high output force, controllable start and stop, and lightweight.

[0082] 5) The materials used (carbon fiber and silicone) are stable, resistant to radiation degradation, ozone resistant, and have excellent cycle stability within the pyrolysis temperature range. They can withstand temperature changes in space and are suitable for service in space.

[0083] In contrast, the inventors of this invention used a simple CF / PDMS composite fiber obtained through simple impregnation followed by drying and curing. The carbon fiber monofilaments in this fiber did not form a uniform composite with PDMS, and its structure was as follows: Figure 8a As shown, the carbon fibers are not adequately protected, making them unable to withstand torsional shear stress. Even with slight twisting, brittle fracture occurs before a helical structure can be formed, rendering them unsuitable for later driving applications. However, through repeated impregnation using the present invention, and through the effects of concentration difference and rolling, a uniform CF / PDMS composite structure is formed, as shown in the diagram. Figure 8b As shown, this structure endows the composite fibers with a certain degree of toughness, enabling them to form uniform helical knots. Furthermore, under electrothermal stimulation, it achieves excellent driving force and driving amount, exhibiting good cycle stability. This indicates that the key structural feature is the thorough coating of carbon fiber monofilaments with PDMS through impregnation followed by rolling.

[0084] The inventors of this invention used artificial muscle fibers made by twisting various carbon nanotube fibers previously developed by their technical team to conduct the aforementioned simulated actuation, and found that the driving force of a single fiber was only 0.2N. Figure 6The assembly method cannot drive the solar panels to rotate; after replacing them with silver-plated nylon composite fibers, although they can maintain good cycle stability at 20% drive, nylon itself cannot conduct electricity and needs to be silver-plated to conduct electricity and realize the conversion of electrical energy to thermal energy to mechanical energy. However, since the oxygen elements inevitably present in the polymer are dissociated by ultraviolet radiation from the sun to form atomic oxygen, atomic oxygen can react with silver, causing damage to the silver surface and forming microcracks. This makes silver prone to oxidation during high temperature and cyclic service, leading to performance degradation or even failure. Theoretically, it is completely unsuitable for use in outer space environments.

[0085] Therefore, based on current experimental results and theoretical verification, only the driving method of CF / PDMS composite fiber provided by this invention is the most suitable for driving solar panels in outer space.

[0086] Based on the above test results, it is clear that the flexible drive structure provided by the embodiments of the present invention utilizes the characteristics of CF / PDMS composite fibers, such as self-conductivity, high driving force, high driving quantity, high cycle life, and high environmental stability, to overcome the problems of low driving force, low driving quantity, and difficulty in adapting to the outer space environment of various existing artificial muscle fibers. By controlling the voltage or the power-on time, the driving quantity and driving force can be precisely controlled, providing a better solution for the drive of solar panels of spacecraft.

[0087] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A flexible drive structure for a solar panel, used to drive the movement of a solar panel on a spacecraft, characterized in that, Includes composite fibers, fixing units, and electrical control units; The composite fiber has an initial twist and includes carbon fiber bundles and a polymer, the polymer including PDMS. The PDMS fully fills the space between the carbon fiber monofilaments, and the adjacent carbon fiber monofilaments are uniformly coated with PDMS to form a stress buffer and mechanical protection layer, so that the composite fiber has flexibility. The method for preparing the composite fiber includes: impregnating carbon fiber bundles in PDMS diluent so that PDMS can penetrate between the monofilaments; after one rolling press, impregnating the initially composite fiber in pure PDMS; after a second extrusion and rolling press or multiple cycles of impregnation-rolling press, heat treatment is performed to solidify the fiber and obtain the composite fiber. The fixing unit is disposed at both ends of the composite fiber, and the two ends of the multiple composite fibers are respectively bundled and fixed into one unit, and the fixing unit at both ends is respectively connected to the solar panel and the spacecraft transmission. The electronic control unit is connected to the carbon fiber bundles at both ends of the composite fiber and is used to apply voltage to the carbon fiber bundles.

2. The flexible drive structure according to claim 1, characterized in that, When the composite fiber is at the initial twist, the composite fiber is in an over-twisted state and has a helical structure.

3. The flexible drive structure according to claim 2, characterized in that, The initial twist value is 2000~2300 turns / m; And / or, the diameter of the composite fiber is 0.5~1 mm; And / or, the diameter of the spiral structure is 1~3 mm and the pitch is 0.3~0.6 mm.

4. The flexible drive structure according to claim 1, characterized in that, The number of carbon fiber monofilaments in the carbon fiber bundle is 1000-10000.

5. The flexible drive structure according to claim 1, characterized in that, The number of composite fibers connected to any of the solar panels is 5-100.

6. The flexible drive structure according to claim 1, characterized in that, The solar panel is connected to the main structure of the spacecraft by a hinge. The two ends of the composite fiber are fixed to the surfaces of the solar panel and the main structure by the fixing unit, respectively, and the hinge point is not located on the extension line of the composite fiber.

7. The flexible drive structure according to claim 1, characterized in that, The polymer at both ends of the composite fiber is removed to expose the carbon fiber monofilaments; The electrodes of the electrical control unit are electrically connected to the exposed carbon fiber monofilaments through cured metal conductive adhesive.

8. The control method for the flexible drive structure according to any one of claims 1-7, characterized in that, include: The electrical control unit applies voltage to the carbon fiber bundles in the composite fiber, and the composite fiber is heated by the Joule heating effect of the carbon fiber bundles. Axial contraction is achieved by untwisting caused by radial expansion. The solar panel is driven to flip by the tendency of the composite fiber contraction through the fixing unit. The angle at which the solar panel flips is adjusted by changing the applied voltage and / or the duration of the energization.

9. The control method according to claim 8, characterized in that, The voltage is 1~7 V.

10. A spacecraft, characterized in that, Includes the flexible drive structure described in any one of claims 1-7.

Images