A microgravity test system for low frequency vibration testing of space vehicles

Abstract

The present application relates to a kind of microgravity test system for space vehicle low-frequency vibration test, including mobile slide, precision optical vibration isolation platform, magnetic attraction device, column and mobile suspension device;Space vehicle components to be measured are placed on mobile slide, and mobile slide is placed on precision optical vibration isolation platform;Magnetic attraction device includes sliding plate, iron plate and permanent magnet;Column is installed on precision optical vibration isolation platform, and supports sliding plate and iron plate;Mobile suspension device includes cow eye wheel, mobile frame and connecting rope, cow eye wheel and permanent magnet are installed on one side of mobile frame, connecting rope connects mobile frame and space vehicle components to be measured, and cow eye wheel is in contact with sliding plate.Compared with prior art, the present application has the advantages of compact structure, small space occupied, easy to realize, stable and reliable, etc., by using cow eye wheel and sliding plate to realize the free movement of space vehicle components in horizontal plane, since cow eye wheel and sliding plate are point contact, the friction coefficient is smaller, and the movement is more free.

Description

TECHNICAL FIELD

[0001] The present application relates to microgravity simulation, and in particular to a microgravity test system for low-frequency vibration test of a space vehicle. BACKGROUND

[0002] Solar wings are important energy supply components of space vehicles, and in recent years have been developing in the direction of large-scale, integration and high power, which has resulted in large flexibility and low-frequency vibration, an important problem that needs to be solved urgently. Due to the weak stiffness and weak damping characteristics of the large flexible solar wing structure of a space vehicle, combined with the absence of atmospheric damping in the space microgravity environment, any disturbance in space can easily cause the solar wing to vibrate, and once the vibration is excited, it is difficult to self-damp. The causes of the vibration of the flexible solar wing mainly come from two aspects. On the one hand, due to the restrictions of launch weight and launch conditions, as well as the demand for large energy of the spacecraft, the space flexible solar wing presents the characteristics of large span, light weight, low stiffness, weak damping and multi-body linkage, and exhibits low frequency, mode density and non-linear dynamics. On the other hand, the flexible solar wing is in a space microgravity environment, and is extremely susceptible to external disturbances to produce vibrations that are difficult to eliminate, such as solar wing cold and hot alternation, thermal shock, spacecraft attitude adjustment, battery wing deployment locking impact, flywheel disturbance and solar wing coupling resonance, etc.

[0003] The spacecraft is in a microgravity environment when in orbit. Therefore, when conducting ground experiments, the gravity of the solar wing should be balanced. At present, there are various ways of gravity balancing for solar wing ground tests, including suspension method, air floating method, etc. Both of these methods are based on the principle of force balance, and an external force is applied to the solar wing in the vertical direction, thereby offsetting the gravity of the solar wing, while not affecting the movement of the solar wing in the horizontal plane. The suspension method is simpler in structure than the air floating method, and does not need to consider issues such as airtightness. Furthermore, after the platform is built, it can be used permanently and does not require much maintenance.

[0004] The suspension method can be divided into two methods: fixed fulcrum and movable fulcrum. The fixed fulcrum suspension method allows the solar wing to bear a vertical upward load and a horizontal force along the rope direction, which affects the movement of the solar wing in the horizontal plane. Although raising the suspension point position can reduce the swing angle, the significant disadvantage is that a large experimental space is required. Therefore, a movable fulcrum suspension method is needed. The application publication number CN117863233A discloses a star table cruising robot ground test system and test method, which uses a double-degree-of-freedom sliding rail suspension method to realize the movement of the suspension point. However, the significant disadvantage is that the friction coefficients of the double-layer sliding rails are superimposed, which causes the experimental target to be unable to move freely in the horizontal plane. In order to further reduce the error, the application publication number CN112918656A discloses a high-altitude balloon-borne solar unmanned aerial vehicle system that uses a balloon method to suspend heavy objects. The advantage of this method is that the target can move freely in the horizontal plane. However, the significant disadvantage is that the balloon is too large in volume, generating a large buoyancy that requires a large space to complete the experiment. In addition, many low-density gases are flammable and dangerous, and the safety of the experiment needs to be considered when using this solution.

[0005] Regarding the air floating method, the application publication number CN118602014A discloses a porous material throttling air floating platform simulation microgravity environment that can be spliced and expanded. However, the significant disadvantage is the high manufacturing cost. The manufacturing precision requirement is high when manufacturing the air floating platform, which is not easy to achieve. The application publication number CN108423202A discloses a micro-low gravity simulation device and simulation test method. A non-contact balance point is formed between the air floating slider (inverted suction bearing) and the magnetic plate, and an adjustable adsorption force is generated by the electromagnet to achieve the ceiling effect. The main advantage is that the air floating platform has very small friction and the electromagnetic adsorption force is adjustable. However, the device has the following disadvantages: (1) A complete set of air floating equipment is needed, including air supply equipment, air path, and air floating slider design, which has a complex structure; (2) The cost is high due to the use of air floating devices, and the processing precision of the magnetic plate is high; (3) The device integrates electromagnetism and air floating, and the overall structure is complex; (4) Under the combined influence of the weight block, the suspended object, the electromagnet, and the permanent magnet adsorption force, the ceiling type air floating platform has insufficient reliability and stability. Especially during large-scale movement of the experimental device (for example: solar wing low frequency / ultra-low frequency large amplitude movement), the downward tension on the suspension device is not necessarily a constant force. At this time, the ceiling type air floating platform is difficult to maintain a constant air gap for a long time.

[0006] In addition, in order to simulate the microgravity environment, the experimental equipment is placed in a large water tank, and the buoyancy in the water is used to balance the gravity. This experimental method has a high cost, requires waterproof experimental equipment, and has a large movement resistance. It is usually used for astronaut training, and this solution is almost never used for ground experiments of large space structures such as solar wings.

[0007] Therefore, it is urgent to design a low-cost, low-friction, free movement in the horizontal plane, easy to achieve the space microgravity experiment platform to meet the experimental requirements of the aerospace field. SUMMARY

[0008] The purpose of the present application is to overcome the above-mentioned prior art of high cost, large friction coefficient or complex structure and poor stability defects and provide a microgravity test system for low-frequency vibration test of space vehicles.

[0009] The purpose of the present application can be achieved by the following technical solutions:

[0010] According to one aspect of the present application, a microgravity test system for low-frequency vibration test of space vehicles is provided, comprising a moving slide, a precision optical vibration isolation platform, a magnetic attraction device, a column and a moving suspension device; the space vehicle component to be tested is placed on the moving slide, and the moving slide is placed on the precision optical vibration isolation platform; the magnetic attraction device comprises a sliding plate, an iron plate and a permanent magnet; one end of the column is installed on the precision optical vibration isolation platform, and the other end supports one side of the sliding plate, and the iron plate is stacked on the other side of the sliding plate; the moving suspension device comprises a bull's eye wheel, a moving frame and a connecting rope, the bull's eye wheel and the permanent magnet are installed on one side of the moving frame, the connecting rope is installed on the other side of the moving frame and connected with the space vehicle component to be tested, and the bull's eye wheel is in contact with the sliding plate.

[0011] As a preferred technical solution, the iron plate is provided with a limiting frame near the surface edge of the moving suspension device.

[0012] As a preferred technical solution, the moving frame comprises a first moving frame, a second moving frame and a third moving frame stacked in sequence, the second moving frame is installed in the middle of the first moving frame, and the bull's eye wheel is installed at the edge of the first moving frame, the permanent magnet is installed in the second moving frame, and the third moving frame is provided on the surface of the second moving frame away from the first moving frame.

[0013] As a preferred technical solution, the height of the bull's eye wheel is higher than the height of the second moving frame and the third moving frame.

[0014] As a preferred technical solution, the adsorption force F between the permanent magnet and the iron plate is F=G1+G2+F N , wherein G1 is the gravity of the space vehicle component to be tested, G2 is the gravity of the moving suspension device, and F N is the vertical downward support force provided by the sliding plate to the moving suspension device.

[0015] As a preferred technical solution, the permanent magnet is a plurality of permanent magnets arranged on the moving frame by a Halbach array.

[0016] As a preferred technical solution, the sliding plate is a glass plate.

[0017] As a preferred technical solution, the connecting rope is an elastic rope.

[0018] As a preferred technical solution, the surface of the sliding plate in contact with the bullseye wheel is coated with a lubricant.

[0019] As a preferred technical solution, the four posts are aluminum profile posts.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1) The present application uses a bullseye wheel and a sliding plate to realize the free movement of a spacecraft component in a horizontal plane. Since the bullseye wheel and the sliding plate are in point contact, the friction coefficient is smaller and the movement is more free. The present application has a compact structure, occupies a small space, is easy to implement, and is stable and reliable.

[0022] 2) The present application sets a limiting frame on the edge of the iron plate to prevent the mobile suspension device from sliding out of the top range of the test system.

[0023] 3) The present application can adapt to the weight of the suspended object required by different experiments by changing the arrangement of permanent magnets, replacing magnets, or changing the thickness of the sliding plate, and can balance the gravitational force under the condition of almost no other external force.

[0024] 4) The sliding plate of the present application uses a glass plate, which has a small friction coefficient. During the movement of the spacecraft component, the rope may form an angle with the vertical direction, and the tension is not vertically upward, which interferes with the movement in the horizontal direction. The use of an elastic rope does not affect the free movement of the spacecraft component in the horizontal and vertical directions. The use of aluminum profile posts can ensure the rigidity and stability of the test system. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Figure 1 is a schematic diagram of the overall structure of the microgravity test system of the present application.

[0026] Figure 2 Figure 2 is a schematic diagram of the structure of the mobile suspension device of the present application.

[0027] Figure 3 Figure 3 is an exploded view of the mobile suspension device of the present application.

[0028] Marked in the figure:

[0029] 1, precision optical vibration isolation platform, 2, column, 3, iron plate, 4, sliding plate, 5, connecting rope, 6, solar wing, 7, corner piece, 8, limiting frame, 9, bull's eye wheel, 10, first moving frame, 11, second moving frame, 12, third moving frame, 13, screw, 14, permanent magnet, 15, drive joint, 16, motor, 17, non-contact excitation device, 18, moving slide, 19, angular displacement sensor. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present application.

[0031] The present application provides a microgravity test system for low-frequency vibration test of space vehicles, comprising a moving slide 18, a precision optical vibration isolation platform 1, a magnetic attraction device, a column 2 and a moving suspension device.

[0032] The space vehicle or the components of the space vehicle, such as the solar wing 6, is placed on the moving slide 18. The moving slide 18 is placed on the precision optical vibration isolation platform 1.

[0033] The column 2 is installed on the four corners of the precision optical vibration isolation platform 1 by screw 13 and corner piece 7, and the column 2 supports the magnetic attraction device. The column 2 can be selected as an aluminum profile column 2 to ensure the stiffness and stability of the experimental system.

[0034] The magnetic attraction device comprises a sliding plate 4, an iron plate 3 and a permanent magnet 14. The sliding plate 4 can be selected as a glass plate, and the iron plate 3 is stacked above the glass plate. The column 2 supports the glass plate and the iron plate 3. The iron plate 3 is provided with a limiting frame 8 at the edge, and the glass plate is located in the limiting frame 8. The permanent magnet 14 is one or more. The attractive force F between the permanent magnet 14 and the iron plate 3 is F=G1+G2+F N , wherein G1 is the gravity of the space vehicle component to be tested, in the present embodiment, the space vehicle component to be tested is the solar wing 6, G1 is the gravity of the solar wing 6, G2 is the gravity of the moving suspension device, and F NThe vertical downward support force provided by the sliding plate to the moving suspension device, i.e. the adsorption force between the permanent magnet 14 and the iron plate 3, is actually slightly greater than the gravity of the solar wing and the moving suspension device, thereby avoiding the risk of the experimental device falling off during movement; the thickness of the sliding plate 4 can be selected according to the weight of the suspended object to adjust the size of the adsorption force. The permanent magnet 14 determines the size of the adsorption force, and the friction force is related to the normal pressure, which is the adsorption force between the permanent magnet 14 and the iron plate 3. The adsorption force between the permanent magnet 14 and the iron plate 3 can be adjusted by changing the size or arrangement of the permanent magnet 14, for example, using multiple permanent magnets 14 and adopting a Halbach array, which can greatly enhance the magnetism of the permanent magnet 14.

[0035] The moving suspension device comprises a bull's eye wheel 9, a moving frame and a connecting rope 5. The moving frame comprises a first moving frame 10, a second moving frame 11 and a third moving frame 12 which are stacked in sequence and connected by screws 13. The area of the second moving frame 11 is smaller than that of the first moving frame 10. The second moving frame 11 is installed in the middle of the first moving frame 10, and the edge is installed with the bull's eye wheel 9 through the screws 13. The permanent magnet 14 is installed in the second moving frame 11 for adsorbing the moving frame on the top sliding plate 4. The four inner corners of the second moving frame 11 can be processed into round corners for easy manufacturing. The third moving frame 12 is arranged on the surface of the second moving frame 11 and can be used to fix the permanent magnet 14. The height of the bull's eye wheel 9 is higher than the height of the stacked second moving frame 11 and third moving frame 12. The bull's eye wheel 9 is in contact with the sliding plate 4, and the contact between the bull's eye wheel 9 and the sliding plate 4 is point contact. The bull's eye wheel 9 can drive the moving frame to make a combined motion of sliding and rolling on the sliding plate 4, and the friction coefficient is extremely small. The surface of the sliding plate 4 in contact with the bull's eye wheel 9 is coated with a lubricant, thereby further reducing the friction coefficient between the suspension device and the glass plate. The moving frame is limited by the limiting frame 8 of the iron plate 3 to prevent the moving suspension device from sliding out of the range of the top of the test system. The connecting rope 5 is connected to the moving frame and connected with the driving joint 15 of the solar wing 6 for lifting the space vehicle components. The connecting rope 5 is an elastic rope. If a rigid rope is selected, the rope may form an angle with the vertical direction during the movement of the solar wing 6, which will interfere with the horizontal movement of the solar wing 6. If it is an elastic rope, it will not affect the free movement of the solar wing 6 in the horizontal and vertical directions.

[0036] The installation and test process of the present application is as follows:

[0037] Screw 13 cooperates with corner piece 7 to install aluminum profile column 2 on four corners of precision optical vibration isolation platform 1, and glass plate and iron plate 3 with limiting frame 8 are placed on four aluminum profile columns 2 in sequence. Mobile suspension device is adsorbed on the top glass plate, and lubrication is observed. The elastic rope on the mobile suspension device is connected with driving joint 15 of solar wing 6. Driving torque is provided by motor 16, and non-contact excitation is given to solar wing 6 by non-contact excitation device 17, and angular displacement sensor 19 is used to collect angular displacement data. Driving joint 15 is powered, active control is started, and joint angular displacement data is collected through angular displacement sensor 19. Solar wing 6 enters the swing state and pulls the elastic rope, and the mobile suspension device on the top of the test system will be pulled by the elastic rope and slide on the glass plate. Thus, driving joint 15 is subjected to an upward vertical pulling force to balance the gravity during the entire experiment, and almost no horizontal external force is applied during the experiment. The power supply of driving joint 15 is disconnected, and the collected data is processed, and the test is completed.

[0038] In summary, compared with the line and surface contact of the two-degree-of-freedom sliding rail suspension method, the point contact between the bullseye wheel 9 and the sliding plate 4 has the advantages of smaller friction coefficient and more free movement. Compared with the balloon method, the present application has the advantages of compact structure and small floor space. Compared with the air floating platform method, the present application has the advantages of lower cost, easier implementation, more stability, and more reliability. In addition, the present application can adapt to the weight of the suspended object required by different experiments by changing the arrangement of permanent magnet 14 or replacing the magnet, and can balance the gravity without generating other external forces. It can meet the experimental requirements in the field of aerospace.

[0039] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A microgravity test system for low frequency vibration testing of a space vehicle, characterized by, The device comprises a mobile sliding table (18), a precision optical vibration isolation platform (1), a magnetic attraction device, a stand (2) and a mobile suspension device; the space vehicle component to be measured is placed on the mobile sliding table (18), which is placed on the precision optical vibration isolation platform (1); the magnetic attraction device comprises a sliding plate (4), an iron plate (3) and a permanent magnet (14); one end of the stand (2) is installed on the precision optical vibration isolation platform (1), and the other end supports one side of the sliding plate (4), and the iron plate (3) is stacked on the other side of the sliding plate (4); the mobile suspension device comprises a bull's eye wheel (9), a mobile frame and a connecting rope (5), the bull's eye wheel (9) and the permanent magnet (14) are installed on one side of the mobile frame, the connecting rope (5) is installed on the other side of the mobile frame and connected with the space vehicle component to be measured, and the bull's eye wheel (9) is in contact with the sliding plate (4). The attraction force between the permanent magnet (14) and the iron plate (3) wherein, is the gravity of the space vehicle component to be tested, is the gravity of the mobile suspension device, is the vertical downward support force provided by the sliding plate (4) to the mobile suspension device.

2. The microgravity test system for low frequency vibration testing of a space vehicle as claimed in claim 1, wherein, The iron plate (3) is provided with a limiting frame (8) near the surface edge of the mobile suspension device.

3. The microgravity test system for low frequency vibration testing of a space vehicle of claim 1, wherein, The mobile frame comprises a first mobile frame (10), a second mobile frame (11) and a third mobile frame (12) stacked in sequence, the second mobile frame (11) is installed in the middle of the first mobile frame (10), and the bull's eye wheel (9) is installed at the edge of the first mobile frame (10), the permanent magnet (14) is installed in the second mobile frame (11), and the third mobile frame (12) is arranged on the surface of the second mobile frame (11) away from the first mobile frame (10).

4. The microgravity test system for low frequency vibration testing of a space vehicle of claim 3, wherein, The height of the bull's eye wheel (9) is higher than the height of the second mobile frame (11) and the third mobile frame (12).

5. The microgravity test system for low frequency vibration testing of a space vehicle of claim 1, wherein, The permanent magnet (14) is a plurality of permanent magnets arranged on the mobile frame through a Halbach array.

6. The microgravity test system for low frequency vibration testing of a space vehicle of claim 1, wherein, The sliding plate (4) is a glass plate.

7. The microgravity test system for low frequency vibration testing of a space vehicle of claim 1, wherein, The connecting rope (5) is an elastic rope.

8. The microgravity test system for low frequency vibration testing of a space vehicle of claim 1, wherein, The surface of the sliding plate (4) in contact with the bull's eye wheel (9) is coated with a lubricant.

9. The microgravity test system for low frequency vibration testing of a space vehicle of claim 1, wherein, The stand (2) is four aluminum profile stands (2) respectively arranged at the four corners of the precision optical vibration isolation platform (1).

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