Multi-stage gravity unloading device for micro-vibration test of spacecraft and test method

Abstract

The invention provides a multi-stage gravity unloading device for a micro-vibration test of a spacecraft. The multi-stage gravity unloading device comprises a platform gravity unloading device, a load supporting truss, a two-dimensional follow-up platform assembly, a load gravity unloading device, a load unfolding mechanism gravity unloading device, a parking support vehicle, an auxiliary positioning tool and an electric lifting device control system. The method is mainly used for simulating a free boundary environment in a ground micro-vibration test of a special spacecraft, simulating that the spacecraft is in a free floating state, verifying a micro-vibration isolation effect and measuring the optical axis directivity of a load; the weight of the spacecraft is suspended and unloaded in parallel through the flexible elastic rope group, so that the low-frequency requirement of free boundary environment simulation is met, and a basic condition is provided for a micro-vibration test; the length of the rope is adjusted through driving of the motor to adjust the position or posture of the end effector, so that the relative posture of the platform and the load is kept fixed, the stress state of the vibration isolation device is equivalent to the space, and the vibration isolation device has important significance in improving the precision of optical axis directivity measurement.

Description

Technical Field

[0001] This invention belongs to the field of spacecraft ground micro-vibration testing technology, specifically, it relates to a multi-stage gravity unloading device and testing method for spacecraft micro-vibration testing. More particularly, it relates to a multi-stage gravity unloading device and testing method for micro-vibration testing of spacecraft with special configurations. Background Technology

[0002] During spacecraft operation in orbit, the normal operation of moving parts within the platform generates micro-vibrations with small amplitude, wide frequency range, and difficult control. These vibrations typically do not damage the structure, but for spacecraft requiring high-precision pointing, the transmission of these micro-vibrations to the load can degrade its pointing performance. Currently, a more effective approach is to install active and passive vibration isolation devices with flexible hinges between the load and the platform, forming a load-isolation-platform configuration to mitigate the impact of micro-vibrations on the load. Simultaneously, ground-based micro-vibration tests are used to verify the vibration transmission characteristics between different parts of the spacecraft and the isolation effect of the isolation devices. For example, invention patent CN105276073A proposes a multi-dimensional, multi-level vibration reduction device that reduces vibrations transmitted to the optical load through a three-stage series isolation structure.

[0003] Conducting micro-vibration tests on the ground first requires a gravity unloading device to achieve low-frequency unloading of the spacecraft in the direction of gravity, providing mechanical testing conditions identical to the space environment. A multi-stage gravity unloading device, designed for payload-isolation-platform configuration spacecraft, unloads the gravity of the platform, payload deployment mechanism, and payload in stages, simulating the free boundary state of on-orbit floating. This ensures that the micro-vibrations transmitted from the disturbance source to the payload are consistent with the weightless state of space. Furthermore, through staged suspension, the active and passive vibration isolation devices bear only their own weight, preventing internal flexible components from bearing the weight of sensitive loads, thus ensuring that the vibration isolation effect is not equivalent to that in space.

[0004] In the invention patent with publication number CN104709476A, a microgravity assembly gravity unloading device for large multi-degree-of-freedom satellite payloads is proposed. It uses a counterweight support, pulley system and steel wire rope to achieve gravity unloading of satellite payloads. The unloading force is adjusted by manually adding or removing discrete counterweights, and it relies on scale positioning and manual adjustment. The device has a single function and low efficiency and unloading accuracy. The rigid steel wire rope structure results in a high suspension frequency, which cannot simulate the low-frequency environment of free floating in space.

[0005] However, when the center of mass of the load or platform deviates or the rope creeps, their relative positions will become misaligned, affecting not only the performance of the vibration isolation device but also reducing the directional accuracy of the load during the test. Therefore, it is necessary to adjust the suspension ropes through electric lifting to keep the positions of the platform and the load relatively fixed. This is of great significance for improving the accuracy of micro-vibration tests and fully reflecting the performance indicators of the spacecraft.

[0006] Based on the deficiencies in the existing technologies, there is an urgent need to develop a multi-stage gravity unloading device and testing method for spacecraft micro-vibration testing. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a multi-stage gravity unloading device and testing method for spacecraft micro-vibration testing.

[0008] The multi-stage gravity unloading device for spacecraft micro-vibration testing provided by the present invention includes: a platform gravity unloading device 2, a load support truss 3, a two-dimensional follow-up platform assembly 4, a load gravity unloading device 5, a load deployment mechanism gravity unloading device 6, a parking support vehicle 7, an auxiliary positioning fixture 8, and an electric lifting device control system 9.

[0009] One end of the platform gravity unloading device 2 is connected to the lower end of the platform suspension gantry 1, and the other end is connected to the platform. It can suspend and unload the weight of the platform and adjust the position and attitude of the platform. The platform suspension gantry 1 can support the platform and the platform gravity unloading device 2.

[0010] The two-dimensional follow-up platform component 4 is installed on the top of the load support truss 3, and can be equipped with the load gravity unloading device 5 to bear the load and the load gravity unloading device 5.

[0011] The load support truss 3 can support the two-dimensional follow-up platform component 4, the load deployment mechanism suspension device, the load, and the load gravity unloading device 5;

[0012] The load unloading device 5 is installed at the lower end of the two-dimensional follow-up platform component 4. It is suitable for connecting with the load, suspending and unloading the gravity of the load, and adjusting the position and attitude of the load.

[0013] The load deployment mechanism gravity unloading device 6 can connect the load support truss 3 and the load deployment mechanism, and is used to suspend and unload the gravity of the load deployment mechanism and adjust the deployment angle of the load deployment mechanism relative to the load.

[0014] The parking support vehicle 7 is used for the transfer of spacecraft and to provide two test modes: fixed support and suspended support.

[0015] The auxiliary positioning fixture 8 is used to connect the load support truss 3 and the parking support vehicle 7 to determine the initial relative position of the load support truss 3 and the parking support vehicle 7.

[0016] The electric lifting device control system 9 is used to issue control commands to the drive motor and regulate the movement of the electric lifting device in order to control the lifting of the load unloading device 5.

[0017] Preferably, the platform gravity unloading device 2 includes: a platform combination lifting ring 201, a platform rigid cable 202, a platform lifting beam 203, a platform electric lifting device 204, a platform elastic rope group 205, a platform adapter tool 206, a platform sling 207, a platform tension sensor 208, a platform lifting accessory 209, and a platform safety sling 210.

[0018] There are multiple rigid platform cables 202, each connected at one end to a platform assembly lifting ring 201 and at the other end to a platform lifting beam 203. The platform lifting beam 203 is square and suitable for installing rigid slings and a platform electric lifting device 204. The platform elastic rope assembly 205 can unload the weight of the platform, with one end connected to a transfer shaft below the platform electric lifting device 204 and the other end connected to a transfer shaft of a platform transfer fixture 206. The platform transfer fixture 206 has a transfer shaft passing through it, and both ends are tightened with lock nuts for axial fixation. The number of platform rigid cables 202, platform electric lifting device 204, and platform elastic rope assemblies 205 are the same.

[0019] Platform tension sensor 208 is used to detect the tension provided by each set of elastic ropes; platform lifting accessory 209 is used to connect the platform to the unloaded spacecraft; platform safety harness 210 is designed for protection, normally it is in a slack state and does not provide tension, but it can provide tension to limit the movement of the spacecraft in the event of sudden overload.

[0020] Preferably, the load-bearing support truss 3 is mainly assembled from three levels of structures, which are built sequentially from bottom to top, including the first-level support truss structure 301, the second-level support truss structure 302, and the third-level support truss structure 303.

[0021] Preferably, the two-dimensional follow-up platform component 4 includes a two-dimensional adjustment device 401, a load lifting mechanism 402, and a rigid rope 403;

[0022] The two-dimensional adjustment device 401 can move in a plane along the guide rail direction, and the load lifting mechanism 402 can drive the rigid rope 403 to move in a vertical direction. The two-dimensional adjustment device 401 is suitable for installing the load lifting mechanism 402, and the hook at the lower end of the rigid rope 403 is suitable for installing the load combination lifting ring 501, which is suitable for adjusting the position of the load relative to the platform.

[0023] Preferably, the load gravity unloading device 5 includes: a load combination lifting ring 501, a load rigid cable 502, a load lifting beam 503, a load electric lifting device 504, a load elastic rope group 505, a load transfer tool 506, a load sling 507, a load tension sensor 508, a load auxiliary lifting tool 509, and a load safety sling 510.

[0024] There are multiple rigid load cables 502, each connected at one end to a load assembly lifting ring 501 and at the other end to a load lifting beam 503. The load lifting beam 503 is triangular or square, suitable for installing rigid slings and a load electric lifting device 504. Its size is smaller than that of the platform lifting beam 203 to prevent contact interference between the platform elastic rope assembly 205 and the beam in the suspended state. The load elastic rope assembly 505 can unload the weight of the load. One end of the load elastic rope assembly 505 is connected to the adapter shaft below the load electric lifting device 504, and the other end is connected to the adapter shaft of the load adapter fixture 506. The number of rigid load cables 502, load electric lifting device 504, and load elastic rope assemblies 505 are the same.

[0025] The load tension sensor 508 is used to detect the tension provided by each set of elastic ropes; the load attachment 509 is used to connect the load of the unloaded spacecraft; the load safety sling 510 is designed for protection, normally it is in a slack state and does not provide tension, but it can provide tension to limit the movement of the spacecraft in the event of a sudden overload.

[0026] Preferably, the gravity unloading device 6 of the load deployment mechanism includes: a rope 601, a guide rail 602, a pulley block 603, and a manual ratchet 604;

[0027] The pulley block 603 is installed on the guide rail 602, which is installed in the middle of the side of the load support truss 3. The guide rail 602 in the middle of the side of the load support truss 3 guides the sling and elastic rope to the top of the load unfolding mechanism, and leads them through the pulley block 603 on the guide rail 602 to the bottom of the load support truss 3. The sling and elastic rope are then unloaded and adjusted by gravity through a manual ratchet.

[0028] The test method for a multi-stage gravity unloading device for spacecraft micro-vibration testing provided by the present invention is divided into fixed support condition and suspended condition according to the boundary conditions of the spacecraft, and includes the following steps:

[0029] Step S1: Connect the locking and releasing mechanism, the active and passive vibration isolation mechanism to the load, install the load onto the platform, and confirm the spacecraft test status;

[0030] Step S2: The spacecraft is transported to the test site via the parking support vehicle 7. The primary structure 301 of the supporting truss is connected to the parking support vehicle 7 via the auxiliary positioning fixture 8 to determine the initial position.

[0031] Step S3: Construct a multi-stage gravity unloading device for micro-vibration testing, including a secondary support truss structure 302, a tertiary support truss structure 303, a platform gravity unloading device 2, a load gravity unloading device 5, and a load deployment mechanism gravity unloading device 6.

[0032] Step S4: By manually driving the pulley block 603 to move along the guide rail 602, the gravity unloading of the load unfolding mechanism is realized;

[0033] Step S5: Disconnect the load from the platform, adjust the suspension system to balance the load gravity and stabilize it, unload the spacecraft load by gravity, and conduct a micro-vibration test under fixed support conditions;

[0034] Step S6: Disconnect the platform from the parking support vehicle 7, adjust the suspension system to balance and stabilize the weight of the entire unit, and unload the platform. The specific operation steps are the same as the load unloading process.

[0035] Step S7: Readjust the load unloading device 5 to balance and stabilize the gravity, and complete the flexible docking of the load and the platform.

[0036] Preferably, step S3 includes the following steps:

[0037] Step S3.1: Based on the theoretical weight of the platform and the load, configure the same number of elastic ropes for each lifting point, and preliminarily calculate the number of elastic ropes required for each lifting point;

[0038] Step S3.2: Construct the platform gravity unloading device 2, the load gravity unloading device 5, and the load deployment mechanism gravity unloading device 6 sequentially from top to bottom.

[0039] Preferably, step S5 includes the following steps:

[0040] Step S5.1: Control the load gravity unloading device 5 to lift and lower through the electric lifting device control system 9, and record the values ​​of the load tension sensors 508 connected in series at each lifting point in real time. When the load is close to the theoretical unloading value, stop unloading.

[0041] Step S5.2: Adjust the number of elastic ropes at each lifting point according to the actual center of mass of the spacecraft to ensure that the elongation of the elastic ropes at each lifting point is consistent, thereby completing the gravity unloading of the spacecraft's load.

[0042] Step S5.3: Conduct a micro-vibration test under the fixed support condition of the platform.

[0043] Preferably, step S7 includes the following steps:

[0044] Step S7.1: First, use a laser tracker to measure the feature point information of the interface between the load and the platform, and calculate the relative pose of the load and the platform;

[0045] Step S7.2: Drive the electric lifting device control system 9, adjust the position of each lifting point of the load, and measure the docking surface information again;

[0046] Repeat steps S7.1 and S7.2 above until the relative position of the load and the platform meets the requirements, and the flexible docking is completed;

[0047] Step S7.3: Conduct a micro-vibration test on the spacecraft under suspension.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. This invention enables gravity unloading of the platform, load, and load deployment mechanism, all via suspension. The load is lifted from three points by a lifting beam, and the platform from four points, realistically simulating the on-orbit state of a spacecraft and providing a test environment for micro-vibrations. It is particularly useful for simulating free boundary environments in ground-based micro-vibration tests of special spacecraft, simulating a spacecraft in a free-floating state, verifying the micro-vibration isolation effect, and measuring the optical axis directionality of the load.

[0050] 2. This invention is of great significance for improving the accuracy of optical axis pointing measurement. The electric lifting device installed on the lifting beam has a single-point control accuracy of no less than 0.02mm for the drive rope. It can level the tilt posture of the load and the platform due to the eccentricity of the center of mass, so that the relative posture of the platform and the load is kept fixed, thereby making the stress state of the vibration isolation device equivalent to the space.

[0051] 3. This invention enables high-precision flexible docking of the platform and payload during simultaneous unloading, allowing for micro-vibration tests of the entire spacecraft under suspension. By using a series of flexible elastic ropes in parallel to suspend and unload the weight of the spacecraft, it meets the low-frequency requirements of free boundary environment simulation and provides the basic conditions for micro-vibration tests.

[0052] 4. This invention is easy to implement and has good adaptability. It can more realistically simulate the working state of the load and platform in space and accurately verify the vibration isolation effect of the active and passive vibration isolation devices. Through the two-dimensional follow-up platform installed on the support truss and the load lifting mechanism, the relative position of the load and the platform can be adjusted. Through the cooperation of each component, the relative posture of the load and the platform can be kept fixed, thereby avoiding the occurrence of misalignment between the two in the test. Attached Figure Description

[0053] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0054] Figure 1 This is a schematic diagram of the ground equipment system of the multi-stage gravity unloading device for spacecraft micro-vibration testing according to the present invention;

[0055] Figure 2 This is a detailed structural diagram of the multi-stage gravity unloading device for spacecraft micro-vibration testing according to the present invention.

[0056] The diagram shows:

[0057] Detailed Implementation

[0058] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0059] A multi-stage gravity unloading device for spacecraft micro-vibration testing, specifically referring to a device that independently unloads gravity from three components of a spacecraft: the platform, the payload, and the payload deployment mechanism. (Refer to...) Figure 1 As shown, a multi-stage gravity unloading device for spacecraft micro-vibration testing includes a platform gravity unloading device 2, a load support truss 3, a two-dimensional follow-up platform assembly 4, a load gravity unloading device 5, a load deployment mechanism gravity unloading device 6, a parking support vehicle 7, an auxiliary positioning fixture 8, and an electric lifting device control system 9.

[0060] Reference Figure 2 As shown, the platform gravity unloading device 2 includes a platform assembly lifting ring 201, a platform rigid cable 202, a platform lifting beam 203, a platform electric lifting device 204, a platform elastic rope assembly 205, a platform adapter tooling 206, a platform sling 207, a platform tension sensor 208, a platform lifting accessory 209, and a platform safety sling 210; the load support truss 3 includes a primary support truss structure 301, a secondary support truss structure 302, and a tertiary support truss structure 303, mainly assembled from the tertiary structure; the two-dimensional follow-up platform component 4 includes... The system includes a two-dimensional adjustment device 401, a load lifting mechanism 402, and a rigid rope 403; the load gravity unloading device 5 includes a load combination lifting ring 501, a load rigid cable 502, a load lifting beam 503, a load electric lifting device 504, a load elastic rope group 505, a load transfer tool 506, a load sling 507, a load tension sensor 508, a load auxiliary lifting tool 509, and a load safety sling 510; the load unfolding mechanism gravity unloading device 6 includes a rope 601, a guide rail 602, a pulley group 603, and a manual ratchet 604.

[0061] Before conducting the experiment, the elastic rope performance was first tested, including tensile ratio testing, creep resistance testing, stiffness and frequency testing, limit testing, and parallel testing. Through screening, an elastic rope with a diameter of 20 mm was selected, and the overall suspension frequency was ensured to be less than 25% of the first-order free mode of the spacecraft. To reduce the impact of creep, the elastic rope was pre-tensioned, and micro-vibration tests were conducted after the creep stabilized.

[0062] A multi-stage gravity unloading test method for spacecraft micro-vibration testing, divided into fixed support condition and suspended condition according to the spacecraft's boundary conditions, includes the following steps:

[0063] Step S1: Connect the locking and releasing mechanism, the active and passive vibration isolation mechanism to the load, install the load onto the platform, and confirm the spacecraft test status;

[0064] Step S2: The spacecraft is transported to the test site via the parking support vehicle 7. The primary structure 301 of the supporting truss is connected to the parking support vehicle 7 via the auxiliary positioning fixture 8 to determine the initial position.

[0065] Step S3: Construct a multi-stage gravity unloading device for micro-vibration testing, including a secondary support truss structure 302, a tertiary support truss structure 303, a platform gravity unloading device 2, a load gravity unloading device 5, and a load deployment mechanism gravity unloading device 6.

[0066] Step S4: By manually driving the pulley block 603 to move along the guide rail 602, the gravity unloading of the load unfolding mechanism is realized;

[0067] Step S5: Disconnect the load from the platform, adjust the suspension system to balance the load gravity and stabilize it, unload the spacecraft load by gravity, and conduct a micro-vibration test under fixed support conditions;

[0068] Step S6: Disconnect the platform from the parking support vehicle 7, adjust the suspension system to balance and stabilize the weight of the entire unit, and unload the platform. The specific operation steps are the same as the load unloading process.

[0069] Step S7: Readjust the load unloading device 5 to balance and stabilize the gravity, and complete the flexible docking of the load and the platform.

[0070] The basic embodiments of this application have been described above. The following describes the application in more detail with reference to preferred embodiments and / or variations of the basic embodiments.

[0071] A multi-stage suspended gravity unloading device for spacecraft includes a platform gravity unloading device 2, a load support truss 3, a two-dimensional follow-up platform assembly 4, a load gravity unloading device 5, a load deployment mechanism gravity unloading device 6, a parking support vehicle 7, an auxiliary positioning fixture 8, and an electric lifting device control system 9.

[0072] The platform suspension gantry 1 is suitable for supporting the platform and the platform gravity unloading device 2; the platform gravity unloading device 2 is installed at the lower end hook of the platform suspension gantry 1, suitable for connecting with the platform, suspending and unloading the platform's gravity, and adjusting the platform's position and attitude; the load support truss 3 is mainly composed of three-level structural splicing, suitable for supporting the two-dimensional follow-up platform assembly 4, the load deployment mechanism suspension device, the load, and the load gravity unloading device 5; the two-dimensional follow-up platform assembly 4 is installed on the top of the load support truss 3, suitable for installing the load gravity unloading device 5, supporting the load, and the load gravity unloading device 5; the load gravity unloading device 5 is installed in the load lifting mechanism 402 in the two-dimensional follow-up platform assembly 4. The lower hook is suitable for connecting to the load, suspending and unloading the load's gravity, and adjusting the load's position and attitude; the load deployment mechanism gravity unloading device 6 is suitable for connecting the load support truss 3 and the load deployment mechanism, used to suspend and unload the gravity of the load deployment mechanism, and adjust the deployment angle of the load deployment mechanism relative to the load; the parking support vehicle 7 is used for the transfer of spacecraft and to provide two test modes: fixed support and suspended support; the auxiliary positioning fixture 8 is used to connect the load support truss 3 and the parking support vehicle 7, and to determine the initial relative position of the load support truss 3 and the parking support vehicle 7; the electric lifting device control system 9 is used to issue control commands to the drive motor and regulate the movement of the electric lifting device.

[0073] Furthermore, the platform gravity unloading device 2 and the load gravity unloading device 5 unload the gravity of the platform and the load respectively through the platform elastic rope group 205 and the load elastic rope group 505. The load deployment mechanism gravity unloading device 6 unloads the gravity of the load deployment mechanism through elastic ropes. All of them use the flexible suspension of elastic ropes to achieve low-frequency unloading of the gravity direction of the load, the load deployment mechanism and the platform in special configuration spacecraft.

[0074] Furthermore, the platform gravity unloading device 2 includes: a platform combination lifting ring 201, a platform rigid cable 202, a platform lifting beam 203, a platform electric lifting device 204, a platform elastic rope group 205, a platform adapter 206, a platform sling 207, a platform tension sensor 208, a platform lifting accessory 209, and a platform safety sling 210; wherein, there are four platform rigid cables 202, one end of each of which is connected to the platform combination lifting ring 201, and the other end is connected to the platform lifting beam 203; the platform lifting beam 203 is square and suitable for installing four rigid slings and the platform electric lifting device 204; the platform adapter 206 has an adapter shaft passing through it, and both ends are tightened with lock nuts for axial fixation; the platform tension sensor 208 is used to detect the tension provided by each group of elastic ropes; the platform lifting accessory 209 is used to connect the platform of the unloaded spacecraft; the platform safety sling 210 is designed for protection, and under normal circumstances it is in a slack state and does not provide tension, but can provide tension to restrict the movement of the spacecraft in the event of sudden overload.

[0075] Furthermore, the load gravity unloading device 5 includes: a load combination lifting ring 501, a load rigid cable 502, a load lifting beam 503, a load electric lifting device 504, a load elastic rope assembly 505, a load transfer tooling 506, a load sling 507, a load tension sensor 508, a load auxiliary lifting device 509, and a load safety sling 510; wherein, there are three load rigid cables 502, one end of each is connected to the load combination lifting ring 501, and the other end is connected to the load lifting beam 503. The load lifting beam 503 is triangular or square, suitable for installing three rigid slings and the load electric lifting device 504. Its size is smaller than that of the platform lifting beam 203 to prevent contact interference between the platform elastic rope assembly 205 and the beam in the suspended state; the load auxiliary lifting device 509 is used to connect the load of the unloaded spacecraft.

[0076] Furthermore, the platform electric lifting device 204 and the load electric lifting device 504 include: a motor, a limit switch, and a screw jack; wherein, the lower end of the screw jack has a transfer shaft passing through it and is axially fixed by a locking nut; there are four platform electric lifting devices 204, which are respectively installed at the four corners of the platform lifting beam 203, and three load electric lifting devices 504, which are respectively installed at the triangle of the load lifting beam 503; by driving the screw lifting device with the motor, the elongation of the platform elastic rope group 205 or the load elastic rope group 505 can be adjusted, thereby realizing the position and attitude adjustment of the connected platform or load.

[0077] Furthermore, the platform elastic rope group 205 and the load elastic rope group 505 are flexible suspension devices. Before use, their performance should be tested to ensure the suspension frequency is lower than the spacecraft's minimum fundamental frequency. Each group of platform elastic rope group 205 and load elastic rope group 505 consists of multiple ropes connected in parallel. The ends of the ropes are bent back and looped, then locked by mechanical pressing with molybdenum rings. One end is connected to the adapter shaft below the platform electric lifting device 204 and the load electric lifting device 504, and the other end is connected to the adapter shaft of the platform adapter fixture 206 and the load adapter fixture 506. To prevent mutual interference between ropes, a gasket is placed between every two ropes for isolation. There are four groups of platform elastic rope groups 205. The number of ropes in each group is allocated based on the platform's mass and center of gravity eccentricity, calculating the required tension for horizontal attitude. There are three groups of load elastic rope groups 505. The number of ropes in each group is allocated based on the load's mass and center of gravity eccentricity, calculating the required tension for horizontal attitude.

[0078] Furthermore, the two-dimensional follow-up platform and its accessory 4 include: a two-dimensional adjustment device 401, a load lifting mechanism 402, and a rigid rope 403. The two-dimensional adjustment device 401 can move in a plane along the guide rail direction, the load lifting mechanism 402 can drive the rigid rope 403 to move in a vertical direction, the two-dimensional adjustment device 401 is suitable for installing the load lifting mechanism 402, and the hook at the lower end of the rigid rope 403 is suitable for installing the load combination lifting ring 501, which is suitable for adjusting the position of the load relative to the platform.

[0079] Furthermore, the gravity unloading device 6 of the load deployment mechanism includes: a rope 601, a guide rail 602, a pulley block 603, and a manual ratchet 604. The pulley block 603 is installed on the guide rail 602, which is installed in the middle of the side of the load support truss 3. Since the load deployment mechanism is relatively lightweight and the suspension points are relatively concentrated, the guide rail 602 in the middle of the side of the load support truss 3 is used for guidance. The sling and elastic rope are connected to the top of the load deployment mechanism, pass through the pulley block 603 on the guide rail 602, and are led to the bottom of the load support truss 3. The gravity unloading and adjustment are performed by the manual ratchet.

[0080] A multi-stage gravity unloading test method for spacecraft micro-vibration testing, divided into fixed support condition and suspended condition according to the spacecraft's boundary conditions, includes the following steps:

[0081] Step S1: Connect the locking and releasing mechanism, the active and passive vibration isolation mechanism to the load, install the load onto the platform, and confirm the spacecraft test status;

[0082] Step S2: The spacecraft is transported to the test site via the parking support vehicle 7. The primary structure 301 of the supporting truss is connected to the parking support vehicle 7 via the auxiliary positioning fixture 8 to determine the initial position.

[0083] Step S3: Construct a multi-stage gravity unloading device for micro-vibration testing, including a secondary support truss structure 302, a tertiary support truss structure 303, a platform gravity unloading device 2, a load gravity unloading device 5, and a load deployment mechanism gravity unloading device 6.

[0084] Step S3.1: Based on the theoretical weight of the platform and the load, configure the same number of elastic ropes for each lifting point, and preliminarily calculate the number of elastic ropes required for each lifting point;

[0085] The total weight of the platform plus tooling accessories is approximately 3143kg. According to the test, each elastic rope can bear 35kg, so at least 90 elastic ropes are needed. The platform adopts a four-point suspension method, with an average of 23 elastic ropes needed per suspension point. Through calculation, the platform suspension ultimately requires 92 elastic ropes.

[0086] The total weight of the spacecraft payload plus tooling accessories is approximately 700 kg, which requires at least 20 elastic ropes. The spacecraft payload adopts a three-point suspension method, requiring an average of 7 elastic ropes per suspension point. Calculations show that the spacecraft payload ultimately requires 21 elastic ropes for suspension.

[0087] Step S3.2: Construct the platform gravity unloading device 2, the load gravity unloading device 5, and the load deployment mechanism gravity unloading device 6 sequentially from top to bottom;

[0088] By controlling the gantry frame 1 suspended from the factory platform and the two-dimensional adjustment device 401, the platform gravity unloading device 2 and the load gravity unloading device 5 are adjusted to a suitable position and connected to the platform and the load respectively.

[0089] Step S4: By manually driving the pulley block 603 to move along the guide rail 602, the gravity unloading of the load unfolding mechanism is realized;

[0090] Step S5: Disconnect the load from the platform, adjust the suspension system to balance the load gravity and stabilize it, unload the spacecraft load by gravity, and conduct a micro-vibration test under fixed support conditions;

[0091] Step S5.1: Control the load gravity unloading device 5 to lift and lower through the electric lifting device control system 9, and record the values ​​of the load tension sensors 508 connected in series at each lifting point in real time. When the load is close to the theoretical unloading value, stop unloading.

[0092] Step S5.2: Adjust the number of elastic ropes at each lifting point according to the actual center of mass of the spacecraft to ensure that the elongation of the elastic ropes at each lifting point is consistent, thereby completing the gravity unloading of the spacecraft's load.

[0093] Step S5.3: Conduct a micro-vibration test on the platform under fixed conditions;

[0094] Step S6: Disconnect the platform from the parking support vehicle 7, adjust the suspension system to balance and stabilize the weight of the entire unit, and unload the platform. The specific operation steps are the same as the load unloading process.

[0095] Step S7: Readjust the load unloading device 5, balance the gravity and stabilize it, complete the flexible docking of the load and the platform, and conduct a micro-vibration test in the vertical suspension state of the whole device.

[0096] Step S7.1: First, use a laser tracker to measure the feature point information of the interface between the load and the platform, and calculate the relative pose of the load and the platform;

[0097] Step S7.2: Drive the electric lifting device control system 9, adjust the position of each lifting point of the load, and measure the docking surface information again;

[0098] Repeat steps S7.1 and S7.2 above until the relative position of the load and the platform meets the requirements, and the flexible docking is completed;

[0099] Step S7.3: Conduct a micro-vibration test on the spacecraft under suspension.

[0100] This invention provides a multi-stage gravity unloading device and test method for spacecraft micro-vibration testing. Based on the characteristics of a load-isolation-platform configuration spacecraft, the load deployment mechanism, load, and platform are all unloaded by suspension, and the flexibility of elastic ropes meets low-frequency conditions. The load is lifted from three points by a lifting beam, and the platform from four points. An electric lifting device mounted on the lifting beam has a single-point control accuracy of no less than 0.02 mm for the drive rope, enabling the leveling of the load and platform due to center-of-gravity eccentricity. A two-dimensional servo platform and load lifting mechanism mounted on the supporting truss can adjust the relative position of the load and platform. Through the cooperation of these components, the relative posture of the load and platform can be kept fixed, thus avoiding misalignment during testing. This multi-stage gravity unloading device has high gravity unloading accuracy, is easy to implement, and has good adaptability. It can more realistically simulate the working state of the load and platform in space and accurately verify the vibration isolation effect of active and passive vibration isolation devices.

[0101] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0102] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A multi-stage gravity unloading device for spacecraft micro-vibration testing, characterized in that, include: Platform gravity unloading device (2), load support truss (3), two-dimensional follow-up platform assembly (4), load gravity unloading device (5), load deployment mechanism gravity unloading device (6), parking support vehicle (7), auxiliary positioning fixture (8) and electric lifting device control system (9); One end of the platform gravity unloading device (2) is connected to the lower end of the platform suspension gantry (1), and the other end is connected to the platform. It can suspend and unload the weight of the platform and adjust the position and attitude of the platform. The platform suspension gantry (1) can support the platform and the platform gravity unloading device (2). The two-dimensional follow-up platform component (4) is installed on the top of the load support truss (3) and can be equipped with a load gravity unloading device (5) to bear the load and the load gravity unloading device (5); The load support truss (3) can support the two-dimensional follow-up platform assembly (4), the load deployment mechanism suspension device, the load, and the load gravity unloading device (5); The load unloading device (5) is installed at the lower end of the two-dimensional follow-up platform assembly (4). It is suitable for connecting with the load, suspending and unloading the gravity of the load, and adjusting the position and attitude of the load. The load deployment mechanism gravity unloading device (6) can connect the load support truss (3) and the load deployment mechanism to suspend and unload the gravity of the load deployment mechanism and adjust the deployment angle of the load deployment mechanism relative to the load. The parking support vehicle (7) is used for the transfer of spacecraft and to provide two test modes: fixed support and suspended support. The auxiliary positioning fixture (8) is used to connect the load support truss (3) and the parking support vehicle (7) to determine the initial relative position of the load support truss (3) and the parking support vehicle (7); The electric lifting device control system (9) is used to issue control commands to the drive motor and regulate the movement of the electric lifting device in order to control the load unloading device (5) to lift.

2. The multi-stage gravity unloading device for spacecraft micro-vibration testing according to claim 1, characterized in that, The platform gravity unloading device (2) includes: a platform combination lifting ring (201), a platform rigid cable (202), a platform lifting beam (203), a platform electric lifting device (204), a platform elastic rope assembly (205), a platform adapter tool (206), a platform sling (207), a platform tension sensor (208), a platform lifting accessory (209), and a platform safety sling (210); There are multiple rigid cables (202) on the platform, one end of which is connected to the platform assembly lifting ring (201), and the other end is connected to the platform lifting beam (203). The platform lifting beam (203) is square and suitable for installing rigid slings and the platform electric lifting device (204). The platform elastic rope group (205) can unload the weight of the platform. One end is connected to the adapter shaft below the platform electric lifting device (204), and the other end is connected to the adapter shaft of the platform adapter fixture (206). The platform adapter fixture (206) has an adapter shaft passing through it, and both ends are tightened with lock nuts for axial fixation. The number of the platform rigid cables (202), the platform electric lifting device (204), and the platform elastic rope group (205) is the same. The platform tension sensor (208) is used to detect the tension provided by each set of elastic ropes; the platform lifting attachment (209) is used to connect the platform of the unloaded spacecraft; the platform safety sling (210) is designed for protection, and is normally in a slack state and does not provide tension, but can provide tension to limit the movement of the spacecraft in the event of a sudden overload.

3. The multi-stage gravity unloading device for spacecraft micro-vibration testing according to claim 1, characterized in that, The load-bearing truss (3) is mainly assembled from three levels of structures, which are built from bottom to top, including the first-level support truss structure (301), the second-level support truss structure (302), and the third-level support truss structure (303).

4. The multi-stage gravity unloading device for spacecraft micro-vibration testing according to claim 1, characterized in that, The two-dimensional follow-up platform component (4) includes a two-dimensional adjustment device (401), a load lifting mechanism (402), and a rigid rope (403); The two-dimensional adjustment device (401) can move in a plane along the guide rail direction, and the load lifting mechanism (402) can drive the rigid rope (403) to move in a vertical direction. The two-dimensional adjustment device (401) is suitable for installing the load lifting mechanism (402), and the hook at the lower end of the rigid rope (403) is suitable for installing the load combination lifting ring (501), which is suitable for adjusting the position of the load relative to the platform.

5. The multi-stage gravity unloading device for spacecraft micro-vibration testing according to claim 1, characterized in that, The load gravity unloading device (5) includes: a load combination lifting ring (501), a load rigid cable (502), a load lifting beam (503), a load electric lifting device (504), a load elastic rope group (505), a load transfer tool (506), a load sling (507), a load tension sensor (508), a load auxiliary lifting tool (509), and a load safety sling (510); There are multiple rigid load cables (502), each connected at one end to a load combination lifting ring (501) and at the other end to a load lifting beam (503). The load lifting beam (503) is triangular or square, suitable for installing rigid slings and load electric lifting device (504). Its size is smaller than that of the platform lifting beam (203) to prevent the platform elastic rope group (205) from contacting and interfering with it in the suspended state. The load elastic rope group (505) can unload the weight of the load. One end of the load elastic rope group (505) is connected to the adapter shaft below the load electric lifting device (504), and the other end is connected to the adapter shaft of the load adapter fixture (506). The number of the rigid load cables (502), the load electric lifting device (504), and the load elastic rope group (505) is the same. The load tension sensor (508) is used to detect the tension provided by each set of elastic ropes; the load attachment (509) is used to connect the load of the unloaded spacecraft; the load safety sling (510) is designed for protection, and is normally in a slack state and does not provide tension, but can provide tension to limit the movement of the spacecraft in the event of a sudden overload.

6. The multi-stage gravity unloading device for spacecraft micro-vibration testing according to claim 1, characterized in that, The load deployment mechanism gravity unloading device (6) includes: a rope (601), a guide rail (602), a pulley block (603), and a manual ratchet (604); The pulley block (603) is installed on the guide rail (602), which is installed in the middle of the side of the load support truss (3). The guide rail (602) in the middle of the side of the load support truss (3) guides the sling and elastic rope to the top of the load unfolding mechanism, and leads them through the pulley block (603) on the guide rail (602) to the bottom of the load support truss (3). The load is unloaded and adjusted by gravity through a manual ratchet.

7. A method for conducting tests using the multi-stage gravity unloading device for spacecraft micro-vibration testing as described in any one of claims 1 to 6, comprising two conditions based on the spacecraft's boundary conditions: a fixed support condition and a suspended condition, characterized in that... Includes the following steps: Step S1: Connect the locking and releasing mechanism, the active and passive vibration isolation mechanism to the load, install the load onto the platform, and confirm the spacecraft test status; Step S2: The spacecraft is transported to the test site via the parking support vehicle (7). The primary structure of the supporting truss (301) is connected to the parking support vehicle (7) via the auxiliary positioning fixture (8) to determine the initial position. Step S3: Construct a multi-stage gravity unloading device for micro-vibration testing, including a secondary structure of the support truss (302), a tertiary structure of the support truss (303), a platform gravity unloading device (2), a load gravity unloading device (5), and a load deployment mechanism gravity unloading device (6). Step S4: By manually driving the pulley block (603) to move along the guide rail (602), the gravity unloading of the load unfolding mechanism is realized; Step S5: Disconnect the load from the platform, adjust the suspension system to balance the load gravity and stabilize it, unload the spacecraft load by gravity, and conduct a micro-vibration test under fixed support conditions; Step S6: Disconnect the platform from the parking support vehicle (7), adjust the suspension system to balance the weight of the entire device and stabilize it, and unload the platform. The specific operation steps are the same as the load unloading process. Step S7: Readjust the load unloading device (5), balance the gravity and stabilize it, and complete the flexible docking of the load and the platform.

8. The method for testing the multi-stage gravity unloading device for spacecraft micro-vibration testing according to claim 7, characterized in that, Step S3 includes the following steps: Step S3.1: Based on the theoretical weight of the platform and the load, configure the same number of elastic ropes for each lifting point, and preliminarily calculate the number of elastic ropes required for each lifting point; Step S3.2: Construct the platform gravity unloading device (2), load gravity unloading device (5), and load deployment mechanism gravity unloading device (6) sequentially from top to bottom.

9. The method for testing the multi-stage gravity unloading device for spacecraft micro-vibration testing according to claim 7, characterized in that, Step S5 includes the following steps: Step S5.1: Control the load gravity unloading device (5) to lift and lower through the electric lifting device control system (9), and record the values ​​of the load tension sensors (508) connected in series at each lifting point in real time. When the load is close to the theoretical unloading value, stop unloading. Step S5.2: Adjust the number of elastic ropes at each lifting point according to the actual center of mass of the spacecraft to ensure that the elongation of the elastic ropes at each lifting point is consistent, thereby completing the gravity unloading of the spacecraft's load. Step S5.3: Conduct a micro-vibration test under the fixed support condition of the platform.

10. The method for testing the multi-stage gravity unloading device for spacecraft micro-vibration testing according to claim 7, characterized in that, Step S7 includes the following steps: Step S7.1: First, use a laser tracker to measure the feature point information of the interface between the load and the platform, and calculate the relative pose of the load and the platform; Step S7.2: Start the electric lifting device control system (9), adjust the position of each lifting point of the load, and measure the docking surface information again; Repeat steps S7.1 and S7.2 until the relative position of the load and the platform meets the requirements, thus completing the flexible docking. Step S7.3: Conduct a micro-vibration test on the spacecraft under suspension.

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