Ground test gravity unloading device and method for simulating space microgravity environment

Abstract

The invention relates to a ground test gravity unloading device for simulating a space microgravity environment. A base is fixedly arranged at the bottom of a fixed frame; a suspension system is arranged above the base and comprises a fixed pulley block mounted on the fixed frame, a pull rope is wound on the fixed pulley block, the bottom of one end of the pull rope is connected with a dynamometer through a tension spring, and the bottom of the other end of the pull rope is wound on a winch mounted on the base; the hoisting system comprises an external excitation device which is suspended right above the detected object; the displacement sensing system comprises a displacement sensor. The device is simple in principle and construction mode, has a relatively ideal controlled unloading mode, has the test advantage of controllable fine adjustment, is mainly used for simulating a space micro-vibration / microgravity environment to carry out a ground test, reproduces a space environment on the ground to the greatest extent so as to verify the functions and performance of a spacecraft and components thereof, and has a wide application prospect. For example, whether the vibration isolator can work reliably on orbit is verified, so that the on-orbit risk is remarkably reduced, the research and development cycle is shortened, and huge cost is saved.

Description

Technical Field

[0001] This invention relates to a ground-based gravity unloading device and method for simulating a microgravity environment in space. Background Technology

[0002] Vibration isolators, as traditional vibration isolation devices, have been widely used in various industries. However, their reliable on-orbit operation still requires extensive testing and verification. Conducting related tests in the space environment is not only infeasible and costly but also highly dangerous. Therefore, simulating the micro-vibration / microgravity environment of space for ground-based testing is one of the important measures to verify the reliable on-orbit operation of vibration isolators. Existing ground-based gravity unloading devices used to simulate the microgravity environment in space have the following problems and shortcomings in verifying the reliable on-orbit operation of vibration isolators: (1) The current mainstream solutions are complex in principle, have high cost, complex construction process, and poor repeatability; (2) It cannot meet the requirements of low natural frequency suspension devices and is limited by fixed site facilities, resulting in poor flexibility.

[0003] (3) The simplified gravity unloading device is not safe and stable enough, and lacks real-time monitoring and quantitative feedback of traction force.

[0004] (4) The adjustment effect of the displacement sensor adjustment device used in the existing gravity unloading device is not obvious and the adjustment accuracy is poor. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a ground test gravity unloading device and method for simulating a microgravity environment in space.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is: a ground test gravity unloading device for simulating a microgravity environment in space, comprising a fixed frame, wherein a base is fixedly provided at the bottom of the fixed frame; A suspension system is provided above the base. The suspension system includes a fixed pulley assembly installed on a fixed frame. A pull rope is wound around the fixed pulley assembly. One end of the pull rope is connected to a force gauge via a tension spring, and the other end is wound around a winch installed on the base. A hoisting system is provided on one side of the base, and the hoisting system includes an external excitation device suspended directly above the object being measured; A displacement sensing system is provided on the other side of the base. The displacement sensing system includes a displacement sensor for detecting the displacement point of the test object with its head facing downwards.

[0007] Preferably, the base is a cast iron base.

[0008] Preferably, the fixed pulley group is installed on the crossbeam at the top of the fixed frame. There are four fixed pulley groups, which are distributed sequentially at the upper left, lower left, upper right, and lower right corners of the fixed frame. There are four pull ropes, each corresponding to one of the four fixed pulley groups. There are four winches, each corresponding to one of the four pull ropes. There are four tension springs, each corresponding to one of the four pull ropes. There are four force gauges, each corresponding to one of the four tension springs. The four force gauges are distributed at the upper left, lower left, upper right, and lower right corners of the object being measured. Lifting rings are fixed at the four corners of the top surface of the object being measured.

[0009] Preferably, the winch is a manual winch with a two-way self-locking function, and the pull rope is an elastic rope.

[0010] Preferably, the hoisting system further includes a hoisting frame that is independently and fixedly installed on a base outside the fixed frame.

[0011] Preferably, the external excitation device is an electromagnetic vibrator, the top of which is suspended on a hoisting frame, and the excitation rod at the bottom of the electromagnetic vibrator is vertically downward and aligned with the object being measured.

[0012] Preferably, a U-shaped support is fixedly connected to the center of the top surface of the object being tested, the excitation rod is vertically aligned with the outer top surface of the support, the displacement sensor is located in the cavity between the support and the top surface of the object being tested, and the test point is the center of the top surface of the object being tested. The test point, the displacement sensor, and the excitation rod are on the same vertical axis.

[0013] Preferably, the displacement sensing system further includes a mounting bracket located independently on the outer side of the fixed frame and the base, and not connected to the fixed frame and the base. A horizontal cantilever is fixed on the mounting bracket, and a lifting cantilever is provided below the horizontal cantilever. An L-shaped rod is fixed at the end of the lifting cantilever near the object being measured, and the displacement sensor is installed at the bottom end of the L-shaped rod.

[0014] Preferably, a lifting adjustment mechanism is provided between the lifting arm and the horizontal arm. The lifting adjustment mechanism includes a vertical guide rod fixed on the horizontal arm and an adjusting screw rotatably mounted on the horizontal arm. The lifting arm is provided with a vertical guide hole and a vertical internal thread hole. The vertical guide rod passes through the vertical guide hole, and the adjusting screw is screwed into the internal thread hole. An external hexagonal adjusting knob is fixed at the top of the adjusting screw.

[0015] A method for operating a ground-based gravity unloading device for simulating a microgravity environment in space includes the following steps: (1) System initialization and gravity unloading: First, connect the connecting hook at the end of the dynamometer of the suspension system to the ring fixed on the object being tested; by manually driving the winch installed on the base, under the guidance and labor-saving effect of the fixed pulley group, the elastic rope is pulled and tensioned smoothly; the low stiffness tension spring connected in series with it deforms and enters the preloaded force state; by observing the unloading force value monitored and displayed in real time by the dynamometer in the force transmission chain, when the force value reaches the preset test threshold, stop driving the winch; at this time, the winch, with its inherent bidirectional self-locking mechanism, can ensure that the tension of the elastic rope is constant, effectively preventing the rebound phenomenon caused by external force fluctuation or system creep, and achieving stable gravity compensation; (2) Deployment of excitation device: After the gravity unloading is completed, the electromagnetic vibrator is independently installed on a special hoisting frame; the excitation device is spatially isolated from the fixed frame and the object under test. Through position calibration, it is ensured that the electromagnetic vibrator and the object under test are vertically connected at the center through the excitation rod. At the same time, the force sensor is installed on the excitation rod. (3) Measurement and calibration: The displacement sensing system is placed as an independent module, separate from the fixed frame and excitation device; using a standard feeler gauge as a reference measuring tool, the initial vertical installation position of the displacement sensor head is finely adjusted by adjusting the knob of the adjusting screw on the lifting adjustment mechanism to ensure that the relative distance between it and the measured point is accurately set within the required range; wherein, the position of the measured point is set at the center of the measured object; at this time, the measured point, displacement sensor, and excitation rod are on the same vertical axis; (4) Test execution: After all the above subsystems have been deployed, loaded and calibrated, the electromagnetic vibrator can be started through electronic devices; by adjusting the magnitude and direction of the current flowing through the coil, the displacement amplitude and frequency of the vibration platform can be controlled, thereby realizing the excitation of the object under test. (5) Data acquisition: After the object under test vibrates, the excitation force generated by the exciter is collected by the force sensor, and the vibration amplitude generated by the force on the object under test is collected by the displacement sensor. Finally, the dynamic mechanical properties of the object under test in simulated weightlessness environment are obtained by MATLAB, Origin or other data processing and analysis software.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The elastic rope-tension spring series combination method used in the suspension system of the present invention reduces the natural frequency of the whole system to a large extent. In the on-orbit weight loss related test of the micro-vibration isolator, it can fully isolate the test frequency range of the unloaded object below, thereby effectively avoiding resonance and ensuring the accuracy of the test.

[0017] (2) The manual winch-pulley transmission system with bidirectional self-locking function adopted in this invention integrates a bidirectional self-locking mechanism based on the ratchet-pulley principle. This not only ensures safety and position maintenance during on-orbit weightlessness tests of the micro-vibration isolator and during load lifting, but also enables the suspension system to conveniently complete target unloading in a controlled manner. In addition, the system achieves real-time monitoring and quantitative feedback of traction force by introducing a force gauge, thereby forming a precise force closed-loop control capability, providing a key guarantee for the accuracy and repeatability of the test results.

[0018] (3) The displacement sensing system used in this invention enables precise and controllable fine-tuning of the distance between the probe of the displacement sensor and the test object during on-orbit weightlessness related tests of the micro-vibration isolator. This mechanism effectively eliminates backlash error and ensures the accuracy and repeatability of positioning. In the initial setup, the gap is calibrated by using a standard feeler gauge, further providing a traceable and high-precision reference installation position for the device.

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the structure of an embodiment of the present invention.

[0021] Figure 2 This is a partial structural illustration of an embodiment of the present invention. Figure 1 .

[0022] Figure 3 This is a partial structural illustration of an embodiment of the present invention. Figure 2 .

[0023] In the diagram: 1. Fixed frame; 2. Base; 3. Fixed pulley block; 4. Pull rope; 5. Tension spring; 6. Force gauge; 7. Winch; 8. External excitation device; 9. Measured object; 10. Displacement sensor; 11. Lifting frame; 12. Bearing seat; 13. Mounting bracket; 14. Horizontal cantilever; 15. Lifting cantilever; 16. L-shaped rod; 17. Vertical guide rod; 18. Adjusting screw; 19. Vertical guide hole; 20. Internal threaded hole; 21. Adjusting knob; 22. Lifting ring. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0027] like Figures 1-3 As shown, this embodiment provides a ground test gravity unloading device for simulating a microgravity environment in space, including a fixed frame 1, and a base 2 fixedly provided at the bottom of the fixed frame; A suspension system is installed above the base. The suspension system includes a fixed pulley group 3 installed on a fixed frame. A pull rope 4 is wound around the fixed pulley group. One end of the pull rope is connected to a force gauge 6 via a tension spring 5, and the other end is wound around a winch 7 installed on the base. The main function of the suspension system is to provide low-friction guidance for the pull rope in the suspension system, effectively avoid the sliding resistance caused by direct contact between the rope and the frame, and ensure a smooth and efficient force transmission path.

[0028] A hoisting system is provided on one side of the base, and the hoisting system includes an external excitation device 8 suspended directly above the object being measured; A displacement sensing system is provided on the other side of the base. The displacement sensing system includes a displacement sensor 10 for detecting the displacement point of the object being measured 9 with its head facing downwards.

[0029] In this embodiment of the invention, the base is a cast iron base. It possesses excellent load-bearing stability and can withstand all the forces generated during the unloading process of the suspension system.

[0030] In this embodiment of the invention, the fixed pulley group is installed on the crossbeam at the top of the fixed frame. There are four fixed pulley groups, which are distributed sequentially at the upper left, lower left, upper right, and lower right corners of the fixed frame. There are four pull ropes, each corresponding to one of the four fixed pulley groups. There are four winches, each corresponding to one of the four pull ropes. There are four tension springs, each corresponding to one of the four pull ropes. There are four force gauges, each corresponding to one of the four tension springs. The four force gauges are distributed at the upper left, lower left, upper right, and lower right corners of the object being measured. A lifting ring 22 is fixed at each of the four corners of the top surface of the object being measured.

[0031] During unloading, tension is applied to the rope by operating the winch, and then the target is unloaded in a controlled manner via the tension spring and force gauge. The introduction of the tension spring significantly reduces the overall natural frequency of the suspension system, effectively isolating it from the test frequency range of the object being unloaded below, thus effectively avoiding resonance and ensuring test accuracy. The force gauge integrated into the system provides real-time quantitative monitoring and feedback of the unloading force.

[0032] In this embodiment of the invention, the winch is a manual winch with a two-way self-locking function, and the pull rope is an elastic rope.

[0033] In this embodiment of the invention, the hoisting system further includes a hoisting frame 11 that is independently and fixedly installed on a base outside the fixed frame.

[0034] In this embodiment of the invention, the external excitation device is an electromagnetic vibrator, the top of which is suspended on a hoisting frame, and the excitation rod at the bottom of which is vertically downward and aligned with the object being measured.

[0035] By spatially isolating and hoisting the electromagnetic vibrator used to generate external excitation from the object under test, the dynamic coupling and mutual interference between the electromagnetic vibrator and the object under test are fundamentally avoided.

[0036] In this embodiment of the invention, a U-shaped support 12 is fixedly connected to the center of the top surface of the object under test. The excitation rod is vertically aligned with the outer top surface of the support 12. The displacement sensor is located in the cavity between the support 12 and the top surface of the object under test. The measured point is the center of the top surface of the object under test. The measured point, the displacement sensor, and the excitation rod are on the same vertical axis.

[0037] In this embodiment of the invention, the displacement sensing system further includes a mounting bracket 13 located independently on the outer side of the fixed frame and the base and not connected to the fixed frame and the base. A horizontal cantilever 14 is fixed on the mounting bracket, and a lifting cantilever 15 is provided below the horizontal cantilever. An L-shaped rod 16 is fixed at the end of the lifting cantilever near the object being measured, and the displacement sensor is installed at the bottom end of the L-shaped rod.

[0038] In this embodiment of the invention, a lifting adjustment mechanism is provided between the lifting arm and the horizontal arm. The lifting adjustment mechanism includes a vertical guide rod 17 fixed on the horizontal arm and an adjusting screw 18 rotatably mounted on the horizontal arm. The lifting arm is provided with a vertical guide hole 19 and a vertical internal thread hole 20. The vertical guide rod passes through the vertical guide hole, and the adjusting screw is screwed into the internal thread hole. The top end of the adjusting screw is fixed with an external hexagonal adjusting knob 21.

[0039] A method for operating a ground-based gravity unloading device for simulating a microgravity environment in space includes the following steps: (1) System initialization and gravity unloading: First, connect the connecting hook at the end of the dynamometer of the suspension system to the ring fixed on the object being tested; by manually driving the winch installed on the base, under the guidance and labor-saving effect of the fixed pulley group, the elastic rope is pulled and tensioned smoothly; the low stiffness tension spring connected in series with it deforms and enters the preloaded force state; by observing the unloading force value monitored and displayed in real time by the dynamometer in the force transmission chain, when the force value reaches the preset test threshold, stop driving the winch; at this time, the winch, with its inherent bidirectional self-locking mechanism, can ensure that the tension of the elastic rope is constant, effectively preventing the rebound phenomenon caused by external force fluctuation or system creep, and achieving stable gravity compensation; (2) Deployment of excitation device: After the gravity unloading is completed, the electromagnetic vibrator is independently installed on a special hoisting frame; the excitation device is spatially isolated from the fixed frame and the object under test. Through position calibration, it is ensured that the electromagnetic vibrator and the object under test are vertically connected at the center through the excitation rod. At the same time, the force sensor is installed on the excitation rod. (3) Measurement and calibration: The displacement sensing system is placed as an independent module, separate from the fixed frame and excitation device; using a standard feeler gauge as a reference measuring tool, the initial vertical installation position of the displacement sensor head is finely adjusted by adjusting the knob of the adjusting screw on the lifting adjustment mechanism to ensure that the relative distance between it and the measured point is accurately set within the required range; wherein, the position of the measured point is set at the center of the measured object; at this time, the measured point, displacement sensor, and excitation rod are on the same vertical axis; (4) Test execution: After all the above subsystems have been deployed, loaded and calibrated, the electromagnetic vibrator can be started through electronic devices; by adjusting the magnitude and direction of the current flowing through the coil, the displacement amplitude and frequency of the vibration platform can be controlled, thereby realizing the excitation of the object under test. (5) Data acquisition: After the object under test vibrates, the excitation force generated by the exciter is collected by the force sensor, and the vibration amplitude generated by the force on the object under test is collected by the displacement sensor. Finally, the dynamic mechanical properties of the object under test in simulated weightlessness environment are obtained by MATLAB, Origin or other data processing and analysis software.

[0040] This invention is simple in principle, easy to build, and has a relatively ideal controlled unloading method. It also has the advantage of controllable fine-tuning for testing. It is mainly used to simulate the micro-vibration / microgravity environment in space for ground tests, to reproduce the space environment on the ground to the greatest extent possible, in order to verify the function and performance of spacecraft and its components, such as verifying whether vibration isolators can work reliably in orbit, thereby significantly reducing on-orbit risks, shortening the research and development cycle, and saving huge costs.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A ground-based gravity unloading device for simulating a microgravity environment in space, characterized in that: It includes a fixed frame, and a base is fixed to the bottom of the fixed frame; A suspension system is provided above the base. The suspension system includes a fixed pulley assembly installed on a fixed frame. A pull rope is wound around the fixed pulley assembly. One end of the pull rope is connected to a force gauge via a tension spring, and the other end is wound around a winch installed on the base. A hoisting system is provided on one side of the base, and the hoisting system includes an external excitation device suspended directly above the object being measured; A displacement sensing system is provided on the other side of the base. The displacement sensing system includes a displacement sensor for detecting the displacement point of the test object with its head facing downwards.

2. The ground-based gravity unloading device for simulating a microgravity environment in space according to claim 1, characterized in that: The base is a cast iron base.

3. The ground-based gravity unloading device for simulating a microgravity environment in space according to claim 1, characterized in that: The fixed pulley system is installed on the crossbeam at the top of the fixed frame. There are four sets of fixed pulleys, which are distributed sequentially at the upper left, lower left, upper right, and lower right corners of the fixed frame. There are four pull ropes, each corresponding to one of the four sets of fixed pulleys. There are four winches, each corresponding to one of the four pull ropes. There are four tension springs, each corresponding to one of the four pull ropes. There are four force gauges, each corresponding to one of the four tension springs. The four force gauges are distributed at the upper left, lower left, upper right, and lower right corners of the object being measured. Lifting rings are fixed at the four corners of the top surface of the object being measured.

4. The ground-based gravity unloading device for simulating a microgravity environment in space according to claim 1, characterized in that: The winch is a manual winch with a two-way self-locking function, and the pull rope is an elastic rope.

5. The ground-based gravity unloading device for simulating a microgravity environment in space according to claim 1, characterized in that: The hoisting system also includes a hoisting frame that is independently and fixedly installed on a base on the outside of the fixed frame.

6. The ground-based gravity unloading device for simulating a microgravity environment in space according to claim 5, characterized in that: The external excitation device is an electromagnetic vibrator. The top of the electromagnetic vibrator is suspended on a hoisting frame, and the excitation rod at the bottom of the electromagnetic vibrator is vertically downward and aligned with the object being measured.

7. The ground-based gravity unloading device for simulating a microgravity environment in space according to claim 6, characterized in that: A U-shaped support is fixedly connected to the center of the top surface of the object under test. The excitation rod is vertically aligned with the outer top surface of the support. The displacement sensor is located in the cavity between the support and the top surface of the object under test. The test point is the center of the top surface of the object under test. The test point, the displacement sensor, and the excitation rod are on the same vertical axis.

8. The ground-based gravity unloading device for simulating a microgravity environment in space according to claim 1, characterized in that: The displacement sensing system also includes a mounting bracket located independently on the outer side of the fixed frame and the base, and not connected to the fixed frame and the base. A horizontal cantilever is fixed on the mounting bracket, and a lifting cantilever is provided below the horizontal cantilever. An L-shaped rod is fixed at the end of the lifting cantilever near the object being measured, and the displacement sensor is installed at the bottom end of the L-shaped rod.

9. The ground-based gravity unloading device for simulating a microgravity environment in space according to claim 8, characterized in that: A lifting adjustment mechanism is provided between the lifting arm and the horizontal arm. The lifting adjustment mechanism includes a vertical guide rod fixed on the horizontal arm and an adjusting screw rotatably mounted on the horizontal arm. The lifting arm is provided with a vertical guide hole and a vertical internal thread hole. The vertical guide rod passes through the vertical guide hole, and the adjusting screw is screwed into the internal thread hole. An external hexagonal adjusting knob is fixed at the top of the adjusting screw.

10. A method for operating a ground-based gravity unloading device for simulating a microgravity environment in space, as described in any one of claims 1-9, characterized in that, Includes the following steps: (1) System initialization and gravity unloading: First, connect the connecting hook at the end of the dynamometer of the suspension system to the ring fixed on the object being tested; by manually driving the winch installed on the base, under the guidance and labor-saving effect of the fixed pulley group, the elastic rope is pulled and tensioned smoothly; the low stiffness tension spring connected in series with it deforms and enters the preloaded force state; by observing the unloading force value monitored and displayed in real time by the dynamometer in the force transmission chain, when the force value reaches the preset test threshold, stop driving the winch; At this time, the winch, with its inherent two-way self-locking mechanism, can ensure that the tension of the elastic rope is constant, effectively preventing the rebound phenomenon caused by external force fluctuations or system creep, and achieving stable gravity compensation. (2) Deployment of excitation device: After the gravity unloading is completed, the electromagnetic vibrator is independently installed on a special hoisting frame; the excitation device is spatially isolated from the fixed frame and the object under test. Through position calibration, it is ensured that the electromagnetic vibrator and the object under test are vertically connected at the center through the excitation rod. At the same time, the force sensor is installed on the excitation rod. (3) Measurement and calibration: The displacement sensing system is placed as an independent module, separate from the fixed frame and excitation device; using a standard feeler gauge as a reference measuring tool, the initial vertical installation position of the displacement sensor head is finely adjusted by adjusting the knob of the adjusting screw on the lifting adjustment mechanism to ensure that the relative distance between it and the measured point is accurately set within the required range; wherein, the position of the measured point is set at the center of the measured object; at this time, the measured point, displacement sensor, and excitation rod are on the same vertical axis; (4) Test execution: After all the above subsystems have been deployed, loaded and calibrated, the electromagnetic vibrator can be started through electronic devices; by adjusting the magnitude and direction of the current flowing through the coil, the displacement amplitude and frequency of the vibration platform can be controlled, thereby realizing the excitation of the object under test. (5) Data acquisition: After the object under test vibrates, the excitation force generated by the exciter is collected by the force sensor, and the vibration amplitude generated by the force on the object under test is collected by the displacement sensor. Finally, the dynamic mechanical properties of the object under test in simulated weightlessness environment are obtained by MATLAB, Origin or other data processing and analysis software.

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