Microgravity test system for low-frequency vibration test of spacecraft

Abstract

The invention relates to a microgravity test system for low-frequency vibration testing of a spacecraft. The microgravity test system comprises a movable sliding table, a precise optical vibration isolation platform, a magnetic attraction device, a stand column and a movable suspension device. A spacecraft component to be measured is placed on the movable sliding table, and the movable sliding table is placed on the precise optical vibration isolation platform. The magnetic suction device comprises a sliding plate, an iron plate and a permanent magnet; the stand column is installed on the precise optical vibration isolation platform and supports the sliding plate and the iron plate. The movable suspension device comprises a bull eye wheel, a movable frame and a connecting rope, the bull eye wheel and the permanent magnet are installed on one face of the movable frame, the connecting rope is connected with the movable frame and the spacecraft component to be tested, and the bull eye wheel makes contact with the sliding plate. Compared with the prior art, free movement of spacecraft components in the horizontal plane is achieved through the bull-eye wheel and the sliding plate, and due to the fact that the bull-eye wheel and the sliding plate are in point contact, the friction coefficient is smaller, and movement is freer; the structure is compact, the occupied space is small, implementation is easy, and stability and reliability are achieved.

Description

Technical Field

[0001] The invention relates to microgravity simulation, and in particular to a microgravity test system for low-frequency vibration testing of spacecraft. Background Art

[0002] Solar wing is an important energy supply component of spacecraft. In recent years, it has developed in the direction of large-scale, integrated and high-power. The resulting large flexibility and low-frequency vibration are important issues that need to be solved urgently. Due to the weak stiffness and weak damping characteristics of large flexible solar wing structures in space, and the lack of atmospheric damping in the microgravity environment of space, any interference in space can easily cause the solar wing to vibrate, and once the vibration is aroused, it is difficult to decay by itself. The reasons for the vibration of flexible solar wings mainly come from two aspects. On the one hand, due to the limitations of launch weight and launch conditions, as well as the large energy requirements of spacecraft, space flexible solar wings have the characteristics of large span, light mass, low stiffness, weak damping and multi-body connection, showing dynamic characteristics such as low frequency, dense modes and nonlinearity. On the other hand, flexible solar wings are in the microgravity environment of space, and are easily disturbed by external interference and produce vibrations that are difficult to eliminate, such as solar wing hot and cold alternation, thermal shock, spacecraft attitude adjustment and orbit change, battery wing deployment and locking impact, flywheel disturbance and solar wing coupling resonance, etc.

[0003] Spacecraft are in a microgravity environment when operating in orbit. Therefore, when conducting ground experiments, the gravity of the solar wing should be balanced. At present, there are many ways to balance the gravity of the solar wing ground test, and the commonly used methods include suspension method and air flotation method. Both methods are based on the principle of force balance, applying external force in the vertical direction to the solar wing to offset the gravity of the solar wing itself, while not affecting the movement of the solar wing in the horizontal plane. Compared with the air flotation method, the suspension method has a simpler structure and does not need to consider issues such as airtightness. In addition, after the platform is built, it can be used permanently without requiring too much maintenance.

[0004] The suspension method is divided into two methods: fixed fulcrum and movable fulcrum. The fixed fulcrum suspension method will cause the solar wing to be subjected to a pulling force in the horizontal plane along the rope direction while being subjected to a vertical upward load, which will also affect the movement of the solar wing in the horizontal plane. Although raising the position of the suspension point can reduce the swing angle, its significant disadvantage is that it requires a large experimental space. Therefore, it is necessary to adopt a suspension method with a movable fulcrum. Application publication number CN117863233A discloses a ground test system and test method for a star chart cruise robot. The suspension method using a double-degree-of-freedom slide rail realizes the movement of the suspension point, but its significant disadvantage is that the friction coefficient of the double-layer slide rail will be superimposed, resulting in the experimental target being unable to move freely in the horizontal plane. In order to further reduce the error, application publication number CN112918656A discloses a high-altitude ball-borne solar drone 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, but its significant disadvantage is that the balloon is too large and generates a large buoyancy that requires a large space to complete the experiment. In addition, many low-density gases are flammable and dangerous, so the safety of the experiment needs to be considered when adopting this approach.

[0005] Regarding the flotation method, application publication number CN118602014A discloses a spliced ​​and expandable porous material throttling flotation platform to simulate a microgravity environment, but its significant disadvantage is the high manufacturing cost. When manufacturing an air flotation platform, high manufacturing precision is required, which is not easy to achieve. Application publication number CN108423202A discloses a micro-low gravity simulation device and a simulation test method, which uses an air flotation slider (inverted suction bearing) and a magnetic conductive plate to form a non-contact balance point, and uses an electromagnet to generate an adjustable adsorption force to achieve a ceiling suction effect. Its main advantages are that the friction of the air flotation platform is extremely small and the electromagnetic adsorption force is adjustable. The disadvantages of this device are: (1) it is necessary to design a complete set of air flotation equipment, including the design of air supply equipment, air circuit, and air flotation slider, and the structure is complex; (2) it involves an air flotation device, which is costly and requires high precision in the surface processing of the magnetic plate; (3) the device integrates electromagnetic and air flotation, and the overall structure is complex; (4) under the combined influence of the counterweight, suspension, electromagnet, and permanent magnet adsorption force, this ceiling-mounted air flotation platform is not reliable and stable enough. Especially during the large-scale movement of the experimental device (for example: the low-frequency / ultra-low-frequency large-scale movement of the solar wing), the downward pull on the suspension device may not be a constant force. At this time, it is difficult for the ceiling-mounted air flotation platform to maintain a constant air gap for a long time.

[0006] In addition, in order to simulate the microgravity environment, another method used is to place the experimental equipment in a large pool and use the buoyancy in the water to balance the gravity. This experimental method is costly and requires the experimental equipment to be waterproof and have high movement resistance. It is usually used for astronaut training and is rarely used for ground experiments on large space structures such as solar wings.

[0007] Therefore, there is an urgent need to design a space microgravity experimental platform with low cost, low friction coefficient, free movement in the horizontal plane, and easy implementation to meet the experimental requirements of the aerospace field. Summary of the invention

[0008] The purpose of the present invention is to provide a microgravity test system for low-frequency vibration testing of spacecraft in order to overcome the defects of the above-mentioned prior art, such as high cost, large friction coefficient or complex structure and poor stability.

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

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

[0011] As a preferred technical solution, a limiting frame is provided on the surface edge of the iron plate close to the movable suspension device.

[0012] As a preferred technical solution, the moving frame includes 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, a bull's eye wheel is installed on the edge, a permanent magnet is installed in the second moving frame, and the third moving frame cover is arranged 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 stacked height of the second moving frame and the third moving frame.

[0014] As a preferred technical solution, the adsorption force between the permanent magnet and the iron plate is F=G1+G2+F N , where G1 is the gravity of the spacecraft component to be measured, G2 is the gravity of the mobile suspension device, and F N The vertical downward support force provided by the sliding plate to the mobile suspension device.

[0015] As a preferred technical solution, there are multiple permanent magnets arranged on the moving frame through 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 bull's eye wheel is coated with a lubricant.

[0019] As a preferred technical solution, there are four columns, which are respectively erected at the four corners of the precision optical vibration isolation platform, and the columns are aluminum profile columns.

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

[0021] 1) The present invention uses a bull's eye wheel and a sliding plate to realize the free movement of spacecraft components in a horizontal plane. Since the bull's eye wheel and the sliding plate are in point contact, the friction coefficient is smaller and the movement is freer; the present invention has a compact structure, occupies a small space, is easy to implement, and is stable and reliable;

[0022] 2) The present invention sets a limit 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 invention can adapt to the weight of the suspended object required for different experiments by changing the arrangement of permanent magnets, replacing magnets or changing the thickness of the sliding plate, and can balance gravity without generating other external forces;

[0024] 4) The sliding plate of the present invention adopts a glass plate with a small friction coefficient; during the movement of the spacecraft components, the rope may form an angle with the vertical direction, and the pulling force is not vertically upward, which interferes with the movement in the horizontal direction. The use of elastic ropes will not affect the free horizontal and vertical movement of the spacecraft components; the use of aluminum profile columns can ensure the rigidity and stability of the experimental system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the microgravity test system of the present invention;

[0026] Figure 2 It is a structural schematic diagram of the mobile suspension device of the present invention;

[0027] Figure 3 It is an exploded view of the mobile suspension device of the present invention;

[0028] The numbers in the figure show:

[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. Limit frame, 9. Bull's eye wheel, 10. First moving frame, 11. Second moving frame, 12. Third moving frame, 13. Screw, 14. Permanent magnet, 15. Driving joint, 16. Motor, 17. Non-contact excitation device, 18. Moving slide, 19. Angular displacement sensor. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

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

[0032] The spacecraft or a part of the spacecraft, such as the solar wing 6 , is placed on the movable slide 18 . The movable slide 18 is placed on the precision optical vibration isolation platform 1 .

[0033] The columns 2 are mounted on the four corners of the precision optical vibration isolation platform 1 with screws 13 and angle pieces 7, and the columns 2 support the magnetic device. The columns 2 can be made of aluminum profiles to ensure the rigidity and stability of the experimental system.

[0034] The magnetic attraction device includes a sliding plate 4, an iron plate 3 and a permanent magnet 14. The sliding plate 4 can be a glass plate. The iron plate 3 is stacked on the glass plate. The column 2 supports the glass plate and the iron plate 3. The edge of the iron plate 3 is provided with a limit frame 8. The glass plate is located in the limit frame 8. There are one or more permanent magnets 14. The adsorption force F between the permanent magnet 14 and the iron plate 3 is G1+G2+F N , where G1 is the gravity of the spacecraft component to be tested. In this embodiment, the spacecraft component to be tested is the solar wing 6, G1 is the gravity of the solar wing 6, G2 is the gravity of the mobile suspension device, and F NThe vertical downward support force provided by the sliding plate to the mobile suspension device, that is, 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 mobile suspension device, 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 magnitude of the adsorption force. The permanent magnet 14 determines the magnitude of the adsorption force. The friction force is related to the positive pressure. The positive pressure here 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 can greatly enhance the magnetism of the permanent magnet 14.

[0035] The movable suspension device comprises a bull's eye wheel 9, a movable frame and a connecting rope 5. The movable frame comprises a first movable frame 10, a second movable frame 11 and a third movable frame 12 which are stacked in sequence and connected by screws 13. The area of ​​the second movable frame 11 is smaller than that of the first movable frame 10. The second movable frame 11 is installed in the middle of the first movable frame 10, and the bull's eye wheel 9 is installed on the edge by screws 13. A permanent magnet 14 is installed in the second movable frame 11 for adsorbing the movable frame on the top sliding plate 4. The four inner corners of the second movable frame 11 can be processed into rounded corners for easy manufacturing. The third movable frame 12 is covered on the surface of the second movable 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 second moving frame 11 and the third moving frame 12 stacked together. The bull's eye wheel 9 contacts the sliding plate 4. 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 slide and roll on the sliding plate 4. 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 limit frame 8 of the iron plate 3 to prevent the mobile suspension device from sliding out of the top range of the test system. The connecting rope 5 is connected to the moving frame and connected to the driving joint 15 of the solar wing 6 to lift the spacecraft components. The connecting rope 5 is an elastic rope. If a rigid rope is selected, during the movement of the solar wing 6, the rope may have a certain angle with the vertical direction, resulting in the rope tension on the solar wing 6 not being vertically upward, which will interfere with the horizontal movement. 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 invention is as follows:

[0037] Use screws 13 to match angle pieces 7 to install aluminum profile columns 2 at the four corners of the precision optical vibration isolation platform 1, and place glass plates and iron plates 3 with limit frames 8 on the four aluminum profile columns 2 in sequence. Adsorb the mobile suspension device on the top glass plate and observe the lubrication condition. Connect the elastic rope on the mobile suspension device to the driving joint 15 of the solar wing 6. The motor 16 provides the driving torque, and the non-contact excitation device 17 gives the solar wing 6 non-contact excitation. The angular displacement sensor 19 is used to collect angular displacement data. Power on the driving joint 15, turn on active control, and collect joint angular displacement data through the angular displacement sensor 19. The solar wing 6 enters the swinging state and pulls the elastic rope. The mobile suspension device at the top of the test system will be pulled by the elastic rope and slip on the glass plate. As a result, the driving joint 15 is subjected to vertical upward pulling force during the entire experiment to balance the gravity, and is almost not subjected to any external force in the horizontal direction during the experiment. Disconnect the power supply of the driving joint 15 and process the collected data, and the experiment is completed.

[0038] In summary, compared with the line and surface contact of the dual-freedom slide rail suspension method, the bull's eye wheel 9 and the sliding plate 4 described in the present invention adopt point contact, which has the advantages of smaller friction coefficient and freer movement; compared with the balloon method, the present invention has the advantages of compact structure and small space; compared with the air floating platform method, the present invention has the advantages of lower cost, easier implementation, more stable and more reliable. In addition, the present invention can balance gravity under the condition of almost no other external force by changing the arrangement of the permanent magnet 14 or replacing the magnet to adapt to the weight of the suspended object required for different experiments. It can meet the experimental requirements in the aerospace field.

[0039] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A microgravity test system for low-frequency vibration testing of spacecraft, characterized in that: The invention comprises a movable slide (18), a precision optical vibration isolation platform (1), a magnetic attraction device, a column (2) and a movable suspension device; a space vehicle component to be tested is placed on the movable slide (18), and the movable slide (18) 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 column (2) is mounted 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 movable suspension device comprises a bull's eye wheel (9), a movable frame and a connecting rope (5); the bull's eye wheel (9) and the permanent magnet (14) are mounted on one side of the movable frame, the connecting rope (5) is mounted on the other side of the movable frame and connected to the space vehicle component to be tested, and the bull's eye wheel (9) is in contact with the sliding plate (4).

2. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 1, characterized in that: The iron plate (3) is provided with a limiting frame (8) at the surface edge close to the movable suspension device.

3. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 1, characterized in that: The movable frame comprises a first movable frame (10), a second movable frame (11) and a third movable frame (12) which are stacked in sequence, the second movable frame (11) being installed in the middle of the first movable frame (10), a bull's eye wheel (9) being installed on the edge, a permanent magnet (14) being installed in the second movable frame (11), and the third movable frame (12) being covered on a surface of the second movable frame (11) away from the first movable frame (10).

4. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 3, characterized in that: The height of the bull's eye wheel (9) is higher than the stacked height of the second moving frame (11) and the third moving frame (12).

5. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 1, characterized in that: The adsorption force between the permanent magnet (14) and the iron plate (3) is F=G1+G2+F N , where G1 is the gravity of the spacecraft component to be measured, G2 is the gravity of the mobile suspension device, and F N The sliding plate (4) provides a vertical downward supporting force to the mobile suspension device.

6. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 1, characterized in that: The permanent magnets (14) are multiple and are arranged on the moving frame through a Halbach array.

7. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 1, characterized in that: The sliding plate (4) is a glass plate.

8. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 1, characterized in that: The connecting rope (5) is an elastic rope.

9. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 1, characterized in that: The surface of the sliding plate (4) in contact with the bull's eye wheel (9) is coated with a lubricant.

10. A microgravity test system for low-frequency vibration testing of spacecraft according to claim 1, characterized in that: There are four columns (2) which are respectively erected at the four corners of the precision optical vibration isolation platform (1); the columns (2) are aluminum profile columns (2).

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