Method and system for testing inherent frequency of micro-vibration vibration isolator

Abstract

The invention provides a micro-vibration isolator inherent frequency test method and system, and the method comprises the steps: fixing a to-be-tested vibration isolator on a test platform, carrying out the gravity unloading of a load mass block and a vibration exciter through a hanging bracket and a gravity unloading mechanism, constructing a test simulation environment, and carrying out the testing of the inherent frequency of the to-be-tested vibration isolator. The gravity unloading mechanism comprises a first unloading spring connected with the load mass block and a second unloading spring connected with the vibration exciter; performing a vibration test on the to-be-tested vibration isolator in the test simulation environment, and collecting a vibration force signal and an acceleration signal when the load mass block and the to-be-tested vibration isolator start to vibrate; fourier transform is carried out on the collected vibration force signals and acceleration signals, an initial frequency response function curve is obtained through calculation, and after smoothing is carried out through an adjacent data point averaging method, the inherent frequency of the vibration isolator to be detected is determined. According to the invention, accurate compensation of the load mass and the weight of the vibration exciter is realized, data burr noise is avoided, and the inherent frequency of the vibration isolator to be tested is accurately determined.

Description

Technical Field

[0001] This application relates to the field of spacecraft micro-vibration control technology, and more specifically, to a method and system for testing the natural frequency of a micro-vibration isolator. Background Technology

[0002] In recent years, the accuracy of my country's remote sensing satellites has rapidly improved. To ensure that the observation accuracy of spacecraft meets the requirements, it is necessary to use micro-vibration isolators to isolate moving components such as control moment gyroscopes and momentum wheels. Conducting ground-based natural frequency tests on micro-vibration isolators is a key measure for evaluating their performance. Isolators based on metal-rubber components have advantages such as non-volatile operation in a vacuum environment, resistance to space radiation, and long fatigue life, making them commonly used in-orbit micro-vibration isolators for spacecraft. However, the stiffness of metal-rubber isolators is highly sensitive to external forces and exhibits strong nonlinearity. While the isolators operate in a weightless environment in orbit, the influence of Earth's gravity during ground testing causes a difference between the frequencies measured on the ground and the actual in-orbit conditions, affecting the evaluation of the isolator's true performance.

[0003] Furthermore, on-orbit micro-vibration isolation components exhibit significant nonlinear stiffness characteristics, making their stiffness highly sensitive to external forces and pre-compression. While the isolator operates in a weightless environment on-orbit, ground testing exposes it to the gravity of the load mass and exciter, causing a shift in its static operating point and resulting in stiffness performance inconsistent with actual on-orbit conditions. Therefore, eliminating gravity interference during ground testing is crucial for accurately evaluating the on-orbit performance of the isolator.

[0004] Therefore, it is necessary to provide a method and system for testing the natural frequency of a micro-vibration isolator to solve one of the aforementioned technical problems. Summary of the Invention

[0005] The purpose of this application is to provide a method and system for testing the natural frequency of a micro-vibration isolator, which can solve at least one of the technical problems mentioned above. The specific solution is as follows:

[0006] According to a specific embodiment of this application, this application provides a method for testing the natural frequency of a micro-vibration isolator, comprising: fixing the isolator under test on a test platform; using a hanger and a gravity unloading mechanism to perform gravity unloading on the load mass block and the exciter to construct a test simulation environment; wherein the gravity unloading mechanism includes a first unloading spring connected to the load mass block and a second unloading spring connected to the exciter; performing a vibration test on the isolator under test within the constructed test simulation environment; when the load mass block and the isolator under test begin to vibrate, acquiring vibration force signals and acceleration signals; performing Fourier transform on the acquired vibration force signals and acceleration signals to calculate the initial frequency response function curve; smoothing the initial frequency response function curve using the adjacent data point averaging method; and determining the natural frequency of the isolator under test based on the smoothed initial frequency response function curve.

[0007] According to a specific embodiment of this application, this application also provides a micro-vibration isolator natural frequency testing system, which executes the micro-vibration isolator natural frequency testing method described in this application, comprising: a test platform installed in a test simulation environment; an isolator to be tested fixedly installed on the test platform; a load mass block connected to the isolator to be tested and installed on the upper end face of the isolator to be tested; an exciter connected to the load mass block and installed on the upper end face of the load mass block; a hanger located above the exciter; and a gravity unloading mechanism including a first gravity unloading spring and a second gravity unloading spring, wherein the first unloading spring is connected to the load mass block and the hanger, and the second unloading spring is connected to the exciter and the hanger, so as to perform gravity unloading processing on the load mass block and the exciter respectively.

[0008] According to specific embodiments of this application, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in any of the preceding claims.

[0009] According to specific embodiments of this application, this application also provides an electronic device, including: one or more processors; and a storage device for storing one or more programs, which, when executed by the one or more processors, cause the one or more processors to perform the method described in any of the preceding claims.

[0010] Compared with the prior art, the above-described solutions of this application have at least the following beneficial effects:

[0011] This application conducts vibration tests on the vibration isolator under test in a constructed test simulation environment. When the load mass block and the vibration isolator under test begin to vibrate, a dual-spring unloading system is used to accurately compensate for the load mass and the weight of the exciter, simulating an on-orbit weightlessness state. Vibration force signals and acceleration signals are collected. Fourier transforms are performed on the collected vibration force signals and acceleration signals to calculate the initial frequency response function curve. The initial frequency response function curve is smoothed using the adjacent data point averaging method. The centrally symmetric adjacent data point averaging method can suppress the burr noise that easily occurs in micro-vibration tests, thereby effectively identifying the peak frequency. The natural frequency of the vibration isolator under test can be accurately determined based on the smoothed initial frequency response function curve.

[0012] In addition, a metal helical tension spring is used to counteract gravity, and the natural frequency of the unloading mechanism is ensured to be much lower than the frequency of the vibration isolator under test, so that the unloading mechanism does not interfere with the test results. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0014] Figure 1 This is a schematic diagram of the structure of the micro-vibration isolator natural frequency testing method according to an embodiment of this application;

[0015] Figure 2 This is a schematic diagram of the structure of an application system for the micro-vibration isolator natural frequency testing method according to an embodiment of this application;

[0016] Figure 3 This is a schematic diagram comparing the effects of smoothing before and after in the natural frequency testing method for micro-vibration isolators according to an embodiment of this application.

[0017] Figure 4 This is a schematic diagram of the electronic device structure shown in an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0020] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0021] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.

[0022] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0023] This application provides a method and system for testing the natural frequency of a micro-vibration isolator. The method involves conducting vibration tests on the isolator under test in a constructed test simulation environment. When the load mass block and the isolator under test begin to vibrate, a dual-spring unloading system accurately compensates for the load mass and the weight of the exciter, simulating an on-orbit weightlessness state. Vibration force and acceleration signals are acquired. Fourier transforms are performed on the acquired vibration force and acceleration signals to calculate the initial frequency response function curve. The initial frequency response function curve is smoothed using an adjacent data point averaging method. This smoothing method, employing central symmetry, suppresses the burr noise that easily occurs in micro-vibration testing, thereby effectively identifying the peak frequency. The natural frequency of the isolator under test can be accurately determined based on the smoothed initial frequency response function curve.

[0024] It should be noted that in this application, the upper (or upper side) and lower (or lower side) end faces of the components or devices in the figure are defined by the upper and lower views of the drawing paper, and the left (or left side) and left (or left side) end faces of the components or devices in the figure are defined by the left and right views of the drawing paper.

[0025] The following is in conjunction with the appendix Figures 1 to 3 Detailed description of optional embodiments of the method of this application.

[0026] like Figure 1 As shown, in step S101, the vibration isolator to be tested is fixed on the test platform, and the load mass block and the exciter are subjected to gravity unloading using a hanger and a gravity unloading mechanism to construct a test simulation environment. The gravity unloading mechanism includes a first unloading spring connected to the load mass block and a second unloading spring connected to the exciter.

[0027] exist Figure 2 In the example, the constructed test simulation environment includes a test platform 1, a vibration isolator 2 fixedly installed on the upper surface of the test platform 1, a load mass block 3 fixedly connected to the upper surface of the vibration isolator 2, and an exciter 4 fixedly connected to the upper surface of the load mass block 3. The test simulation environment also includes the gravity unloading mechanism, which is used to perform gravity unloading on the load mass block 3 and the exciter 4. The load mass block and the exciter are subjected to gravity unloading using a hanger and the gravity unloading mechanism.

[0028] Specifically, a ground rail in the mechanical testing laboratory or a transition plate mounted on the ground rail is used as the test platform 1 to ensure that the test platform 1 has sufficient mass and stiffness to ensure that the vibration isolator 2 under test is under fixed boundary conditions after installation. For example, the test platform 1 is provided with threaded holes, and the vibration isolator 2 under test is fixedly installed on the test platform 1 by screws. A threaded hole is provided at the center of the upper end face of the load mass block 3, and it is connected to the actuating end of the exciter 4 by screws.

[0029] The gravity unloading mechanism includes a first unloading spring 6 connected to the load mass 3 blocks and a second unloading spring 7 connected to the vibrator 4. There are multiple first unloading springs 6 and multiple second unloading springs 7.

[0030] Furthermore, multiple first unloading springs 6 are symmetrically arranged on the upper surface of the load mass block 3, and the load mass block 3 and the multiple first unloading springs 6 form a first spring oscillator for gravity unloading of the load mass block 3. Multiple second unloading springs 7 are symmetrically arranged on the upper surface of the vibrator 4, and the vibrator 4 and the multiple second unloading springs 7 form a second spring oscillator for gravity unloading of the vibrator 4. The first end (lower end) of the first unloading spring 6 is connected to the upper surface of the load mass block 3, and the second end (upper end) of the first unloading spring 6 is connected to the hanger 5. The first end (lower end) of the second unloading spring 7 is connected to the upper surface of the vibrator 4, and the second end (upper end) of the second unloading spring 7 is connected to the hanger 5. A first tension gauge 8 is also provided on the first unloading spring 6, and a second tension gauge 9 is also provided on the second unloading spring 7.

[0031] For example, four first unloading springs 6 are evenly distributed above the load mass block 3 and connected to the upper end face of the load mass block 3. Four second unloading springs 7 are evenly distributed above the vibrator 4 and connected to the upper end face of the vibrator 4.

[0032] For gravity compensation using multiple unloading springs, metal helical tension springs are used to counteract gravity, and the natural frequency of the gravity unloading mechanism is ensured to be much lower than the design frequency of the vibration isolator (e.g., less than 1 / 5 to 1 / 10), so as to effectively ensure that the unloading mechanism does not interfere with the test results.

[0033] Specifically, multiple first unloading springs are symmetrically arranged on the upper surface of the load mass block, and the natural frequency of the first spring oscillator formed by the load mass block and the multiple first unloading springs is lower than the design value of the natural frequency of the vibration isolator under test. The relationship between the natural frequency of the first spring oscillator and the design value of the natural frequency of the vibration isolator under test is characterized by the following expression:

[0034]

[0035] Wherein, f0 represents the natural frequency design value of the vibration isolator under test; m1 represents the mass of the load mass block; n1 represents the number of first unloading springs; k1 represents the stiffness of a single first unloading spring; S represents the first adjustment coefficient (hereinafter referred to as the first adjustment coefficient) of the natural frequency of the first spring oscillator relative to the design natural frequency of the vibration isolator, and the value of the first adjustment coefficient S is 1 / 5 to 1 / 10.

[0036] It should be noted that in this embodiment, the first adjustment coefficient S is 1 / 10, but it is not limited to this. In other embodiments, the first adjustment coefficient S can also be 1 / 5 or 3 / 20, and the range of values ​​for the first adjustment coefficient S is determined according to the actual available spring stiffness. The above is only an optional example and should not be construed as a limitation of this application.

[0037] Multiple second unloading springs are symmetrically arranged on the upper end face of the exciter, and the natural frequency of the second spring oscillator formed by the exciter and the multiple second unloading springs is lower than the design value of the natural frequency of the vibration isolator under test. The relationship between the natural frequency of the second spring oscillator and the design value of the natural frequency of the vibration isolator under test is characterized by the following expression:

[0038]

[0039] Wherein, f0 represents the natural frequency design value of the vibration isolator under test; m2 represents the mass of the load mass block; n2 represents the number of second unloading springs; k2 represents the stiffness of a single second unloading spring; S' represents the second adjustment coefficient (hereinafter referred to as the second adjustment coefficient) of the natural frequency of the second spring oscillator relative to the design natural frequency of the vibration isolator, and the value of the second adjustment coefficient S' is 1 / 5 to 1 / 10.

[0040] It should be noted that in this embodiment, the second adjustment coefficient S' is 1 / 10, but it is not limited to this. In other embodiments, the second adjustment coefficient S' can also be 1 / 5 or 3 / 20, and the range of values ​​for the second adjustment coefficient S' is determined according to the actual available spring stiffness. The above is only an optional example and should not be construed as a limitation of this application.

[0041] By using the above-mentioned stiffness quantification method and selecting two more reasonable unloading spring stiffnesses based on the first and second adjustment coefficients, frequency coupling between the test device and the test object can be effectively avoided.

[0042] It should be noted that the above is only an optional example and should not be construed as a limitation of this application.

[0043] Next, in step S102, the vibration isolator under test is subjected to vibration test in the constructed test simulation environment. When the load mass block and the vibration isolator under test start to vibrate, vibration force signal and acceleration signal are collected.

[0044] Vibration tests were conducted on the vibration isolator under test within the constructed test simulation environment to determine the natural frequency of the vibration isolator under test.

[0045] Acceleration signals during the vibration test are collected using at least one accelerometer sensor positioned on the upper surface of the load mass block.

[0046] exist Figure 2 In the example, an acceleration sensor 11 is installed on the upper surface of the load mass block 3. The exciter 4 is connected to the vibration control acquisition module 15 via a control cable 12 and a first measurement cable 13. The control cable 12 controls the exciter 4 to vibrate, generating a sweep frequency excitation force (hereinafter sometimes simply referred to as "excitation force"), and outputs the sweep frequency excitation force. This force is applied to the load mass block and further transmitted to the vibration isolator under test to excite the load mass block 3 and the vibration isolator 4. The actual vibration force signal output by the exciter 4 is acquired by the vibration control acquisition module 15 via the first measurement cable 13. The acceleration sensor 11 is connected to the vibration control acquisition module 15 via a second measurement cable 14. The vibration control acquisition module 15 is used to acquire the sweep frequency excitation force (i.e., vibration force signal) output by the exciter 4 and the acceleration signal output by the acceleration sensor 11.

[0047] Furthermore, the vibration control acquisition module 15 is connected to the data processing computer 16. The data processing computer 16 performs data processing and analysis on the vibration force signal and acceleration signal.

[0048] Specifically, the exciter 4 outputs a sweeping excitation force with a frequency bandwidth of, for example, 5Hz to 500Hz, covering the natural frequency of the vibration isolator under test. Based on the disturbance force characteristics of real vibration sources such as spacecraft momentum wheels, the exciter can output an excitation force with an amplitude of, for example, 0N to 5N, causing the vibration isolator and the load mass block to generate micro-vibration acceleration of a sufficient magnitude.

[0049] When the load mass block and the vibration isolator under test begin to vibrate, vibration force and acceleration signals are acquired. The actual sweep frequency excitation force output by the exciter is fed back to the vibration control acquisition module in real time via a measuring cable.

[0050] It should be noted that the above is only an optional example and should not be construed as a limitation of this application.

[0051] Next, in step S103, the collected vibration force signal and acceleration signal are subjected to Fourier transform to calculate the initial frequency response function curve. The initial frequency response function curve is smoothed by averaging adjacent data points. The natural frequency of the vibration isolator under test is determined based on the smoothed initial frequency response function curve.

[0052] Specifically, Fourier transforms are performed on the collected vibration force signal (i.e., excitation force) and acceleration signal to obtain the Fourier transforms of the excitation force and the acceleration.

[0053] For example, a data processing computer can be used to perform Fourier transforms on the excitation force and acceleration to obtain the Fourier transform of the excitation force F(ω) and the Fourier transform of the acceleration A(ω).

[0054] Furthermore, the ratio of the Fourier transform of the excitation force to the Fourier transform of the acceleration is calculated, that is, the ratio of A(ω) to F(ω), to obtain the initial frequency response function curve of the vibration isolator under test. For example, T(ω) is used to represent the frequency response function of the vibration isolator under test, that is, the curve characterizing the amplitude as a function of frequency.

[0055] It should be noted that due to noise in the test environment and test system, the initial frequency response function curve has spikes, making it difficult to accurately identify the natural frequency of the vibration isolator under test. Therefore, the initial frequency response function curve is first smoothed to remove the spikes.

[0056] Specifically, the initial frequency response function curve is smoothed using the averaging method of adjacent data points, and the smoothed initial frequency response function curve is represented by the following expression:

[0057] T1(ω i )=(T0(ω i-m )+…T0(ω i-2 )+T0(ω i-1 )+T0(ω i )+T0(ω i+1 )+T0(ω i+2 )+…+T0(ω i+m )) / (2m+1)

[0058] Where, T1(ω i T0(ω) represents the initial frequency response function curve after smoothing, used to characterize the amplitude as a function of frequency. i ) represents the initial frequency response function curve without smoothing, ω i Let i represent the i-th frequency point, where i is 1, 2, ..., N; (2m+1) represents the number of frequency points for smoothing the initial frequency response function curve. Taking the i-th frequency point as the center, m frequency points are taken on both sides of the center point, and a total of 2m+1 frequency points are taken. The amplitude points corresponding to these frequency points are summed, and then the average value is calculated.

[0059] Furthermore, based on the initial frequency response function curve after smoothing, the frequency corresponding to the peak value of the smoothed curve is extracted as the natural frequency of the vibration isolator under test.

[0060] For the value of 2m+1, it is calculated by specifying the average processing frequency bandwidth Δf and combining it with the frequency sampling resolution df during vibration testing, and is expressed by the following expression:

[0061] 2m+1=Δf / df,

[0062]

[0063] Where m represents the number of data points selected from the center of the frequency point to the left and right; Δf represents the specified frequency bandwidth for average processing; df represents the frequency sampling resolution, which is the difference between two adjacent frequency points on the frequency response function curve, i.e., df = ω i -ω i-1 ω i ω represents the frequency value corresponding to the i-th frequency point; i-1 This represents the frequency value corresponding to the (i-1)th frequency point, where i is a positive integer, specifically 2, 3, ..., N; the value of df is configured according to the vibration control acquisition module when acquiring vibration data.

[0064] Optionally, the frequency bandwidth Δf is set to 1Hz to 2Hz. When the frequency bandwidth Δf is set to 1Hz to 2Hz, over-smoothing can be effectively avoided, and glitch noise can be effectively removed.

[0065] Taking a vibration test frequency sampling resolution df of 0.065Hz and an average processing frequency bandwidth Δf of 1Hz as an example, 2m+1=Δf / df=15.4≈15 is used as an example to illustrate the smoothing effect of the curve. See details... Figure 3 .from Figure 3 As can be seen from the above, the initial frequency response function curve after the above smoothing process (corresponding to) Figure 3 The processed data curve (represented by the black curve) is compared to the initial frequency response function curve (corresponding to the unsmoothed curve). Figure 3 The original data curve (represented by the gray curve) should be smoothed and burrs eliminated.

[0066] Using the initial frequency response function curve after the above smoothing process, and the selected 2m+1 value, the average value of the curve peak is calculated to determine the natural frequency of the vibration isolator under test.

[0067] It should be noted that the above is only an optional example and should not be construed as a limitation of this application.

[0068] Compared with existing technologies, this application conducts vibration tests on the isolator under test in a constructed test simulation environment. When the load mass block and the isolator under test begin to vibrate, a dual-spring unloading system is used to accurately compensate for the load mass and the weight of the exciter, simulating an on-orbit weightlessness state. Vibration force signals and acceleration signals are collected; Fourier transforms are performed on the collected vibration force signals and acceleration signals to calculate the initial frequency response function curve; the initial frequency response function curve is smoothed using the averaging method of adjacent data points. The smoothing method using the centrally symmetric averaging method of adjacent data points can suppress the burr noise that easily occurs in micro-vibration tests, thereby effectively identifying the peak frequency; the natural frequency of the isolator under test can be accurately determined based on the smoothed initial frequency response function curve.

[0069] In addition, a metal helical tension spring is used to counteract gravity, and the natural frequency of the unloading mechanism is ensured to be much lower than the frequency of the vibration isolator under test, so that the unloading mechanism does not interfere with the test results.

[0070] The following is in conjunction with the appendix Figure 2 Detailed description of optional embodiments of the system in this application.

[0071] Reference Figure 2 This application also provides a micro-vibration isolator natural frequency testing system, which performs the micro-vibration isolator natural frequency testing method described in this application.

[0072] Specifically, the micro-vibration isolator natural frequency testing system includes a test platform 1, an isolator 2 fixedly installed on the test platform 1, a load mass block 3 connected to the isolator 2, an exciter 4 connected to the load mass block 3, a hanger 5 located above the exciter 4, and a gravity unloading mechanism.

[0073] from Figure 2 As can be seen, test platform 1 is installed within the test simulation environment. The vibration isolator 2 under test is fixedly installed on test platform 1. Load mass block 3 is connected to the vibration isolator 2 under test and installed on its upper surface. Exciter 4 is connected to the load mass block 3 and installed on its upper surface. Hanger 5 is located above the exciter 4. The gravity unloading mechanism includes a first gravity unloading spring 6 and a second gravity unloading spring 7. The first unloading spring 6 is connected to the load mass block 3 and hanger 5, and the second unloading spring 7 is connected to the exciter 4 and hanger 5, so that gravity unloading processes are respectively applied to the load mass block 3 and the exciter 4.

[0074] Specifically, the natural frequency testing system for the micro-vibration isolator further includes a first tension gauge 8 and a second tension gauge 9. The first tension gauge 8 is used to detect the tension required to unload the load mass block 3. The second tension gauge is used to detect the tension required to unload the exciter. An acceleration sensor 11 is installed on the upper surface of the load mass block 3. The control and acquisition module 15 is used to acquire the actual sweep frequency excitation force output by the exciter 4 and the acceleration output by the acceleration sensor 11.

[0075] For accelerometers, such as micro-vibration accelerometers, the sensitivity coefficient is better than 1000 mV / g and the measurement accuracy is better than 1×10⁻⁶. -3 g. Two or four accelerometers can be used, evenly and symmetrically arranged on the top surface of the load mass block. During vibration measurement and data analysis, data from multiple sensors can be averaged, which can effectively reduce installation errors caused by test system installation and environmental interference, and improve the accuracy of test results.

[0076] More specifically, a ground rail in the mechanical testing laboratory or an adapter plate mounted on the ground rail is used as the test platform 1 to ensure that the test platform 1 has sufficient mass and stiffness to ensure that the vibration isolator 2 under test is in a fixed-support boundary condition after installation. For example, the test platform 1 is provided with threaded holes, and the vibration isolator 2 under test is fixedly installed on the test platform 1 by screws.

[0077] Furthermore, a threaded hole is provided at the center of the upper end face of the load mass block 3, which is connected to the actuating end of the vibrator 4 by a screw. The mass of the load mass block 3 is consistent with that of the actual on-orbit vibration isolation object. The gravity unloading mechanism includes a first unloading spring 6 connected to the load mass block 3 and a second unloading spring 7 connected to the vibrator 4. There are multiple first unloading springs 6 and multiple second unloading springs 7.

[0078] from Figure 2 As can be seen from this, the vibrator 4 is fixed at the center of the upper end face of the unloading mass block 3.

[0079] Since the vibrator 4 is installed at the center of the upper surface of the load mass block 3, the gravity unloading spring cannot be connected to the center of the load mass block. In order to avoid the tension being eccentric, multiple first unloading springs 6 can be evenly and symmetrically distributed and connected to the top surface of the load mass block, which can effectively prevent the tension from creeping during long-term testing.

[0080] Specifically, multiple first unloading springs 6 are symmetrically arranged on the upper surface of the load mass block 3, and the load mass block 3 and the multiple first unloading springs 6 form a first spring oscillator for gravity unloading of the load mass block 3. Multiple second unloading springs 7 are symmetrically arranged on the upper surface of the vibrator 4, and the vibrator 4 and the multiple second unloading springs 7 form a second spring oscillator for gravity unloading of the vibrator 4. The first end (lower end) of the first unloading spring 6 is connected to the upper surface of the load mass block 3, and the second end (upper end) of the first unloading spring 6 is connected to the hanger 5. The first end (lower end) of the second unloading spring 7 is connected to the upper surface of the vibrator 4, and the second end (upper end) of the second unloading spring 7 is connected to the hanger 5. A first tension gauge 8 is also provided on the first unloading spring 6, and a second tension gauge 9 is also provided on the second unloading spring 7. The first tension gauge 8 is used to detect the tension required to unload the load mass block 3. The second tension gauge 9 is used to detect the tension required to unload the vibrator 4.

[0081] For example, four first unloading springs 6 are evenly distributed (axisymmetrically) above the load mass block 3 and connected to the upper end face of the load mass block 3, which can effectively avoid eccentric force and more accurately unload the weight of the load mass block. Four second unloading springs 7 are evenly distributed (axisymmetrically) above the vibrator 4 and connected to the upper end face of the vibrator 4, which can effectively avoid eccentric force and more accurately unload the weight of the vibrator. Both the first unloading springs 6 and the second unloading springs 7 are metal cylindrical helical springs.

[0082] For gravity compensation using multiple unloading springs, metal helical tension springs are used to counteract gravity, and the natural frequency of the gravity unloading mechanism is ensured to be much lower than the vibration isolator frequency (e.g., less than 1 / 5 to 1 / 10) to effectively ensure that the unloading mechanism does not interfere with the test results.

[0083] Optionally, multiple first unloading springs are symmetrically arranged on the upper surface of the load mass block, and the natural frequency of the first spring oscillator formed by the load mass block and the multiple first unloading springs is lower than the design value of the natural frequency of the vibration isolator under test. The relationship between the natural frequency of the first spring oscillator and the design value of the natural frequency of the vibration isolator under test is characterized by the following expression:

[0084]

[0085] Wherein, f0 represents the natural frequency design value of the vibration isolator under test; m1 represents the mass of the load mass block; n1 represents the number of first unloading springs; k1 represents the stiffness of a single first unloading spring; S represents the first adjustment coefficient of the natural frequency of the first spring oscillator relative to the design natural frequency of the vibration isolator, and the value of the first adjustment coefficient S is 1 / 5 to 1 / 10.

[0086] Multiple second unloading springs are symmetrically arranged on the upper end face of the exciter, and the natural frequency of the second spring oscillator formed by the exciter and the multiple second unloading springs is lower than the design value of the natural frequency of the vibration isolator under test. The relationship between the natural frequency of the second spring oscillator and the design value of the natural frequency of the vibration isolator under test is characterized by the following expression:

[0087]

[0088] Wherein, f0 represents the natural frequency design value of the vibration isolator under test; m2 represents the mass of the load mass block; n2 represents the number of second unloading springs; k2 represents the stiffness of a single second unloading spring; S' represents the second adjustment coefficient of the natural frequency of the second spring oscillator relative to the design natural frequency of the vibration isolator, and the value of the second adjustment coefficient S' is 1 / 5 to 1 / 10.

[0089] It should be noted that, based on the disturbance force characteristics of real disturbance sources such as the spacecraft momentum wheel, the vibration isolator and the load mass block generate micro-vibration acceleration of a sufficient magnitude to meet the simulated vibration test environment conditions.

[0090] For vibration testing of the isolator under test, when the vibration test begins, the vibration control acquisition module 15 is activated, and the exciter 4 is controlled to vibrate via the control cable 12 to generate a sweep frequency excitation force (e.g., an excitation force with an amplitude of 0N to 5N). The sweep frequency excitation force is then applied to the load mass block and further transmitted to the isolator under test to excite the load mass block 3 and the isolator 4 (i.e., to make the isolator under test vibrate with the load mass block). For example, the excitation frequency range is 5Hz to 500Hz.

[0091] Specifically, the exciter 4 is an electromagnetic exciter, capable of outputting excitation force with a frequency bandwidth of 5Hz to 500Hz, thereby covering the natural frequency of the vibration isolator 2 under test. The vibration force signal output by the exciter 4 (e.g., 0N to 5N) causes the entire system to generate micro-vibration acceleration. The acceleration sensor 11 (e.g., with a sensitivity better than 1000mv / g) collects the generated acceleration signal in real time and feeds back the collected vibration force signal and acceleration signal to the vibration control acquisition module 15. Specifically, the vibration force signal actually output by the exciter 4 is collected by the vibration control acquisition module 15 through the first measurement cable 13. The acceleration sensor 11 is connected to the vibration control acquisition module 15 through the second measurement cable 14. In other words, the vibration control acquisition module 15 is used to collect the sweep frequency excitation force (i.e., vibration force signal) output by the exciter 4 and the acceleration signal output by the acceleration sensor 11.

[0092] Furthermore, the vibration control acquisition module 15 is connected to the data processing computer 16. The data processing computer 16 performs data processing and analysis on the vibration force signal and acceleration signal.

[0093] It should be noted that the vibration testing, data acquisition, and data processing of the vibration isolator under test within the constructed test simulation environment are largely the same as the method for testing the natural frequency of the micro-vibration isolator in this application. Therefore, the description of the same content is omitted.

[0094] Compared with existing technologies, this application conducts vibration tests on the isolator under test in a constructed test simulation environment. When the load mass block and the isolator under test begin to vibrate, a dual-spring unloading system is used to accurately compensate for the load mass and the weight of the exciter, simulating an on-orbit weightlessness state. Vibration force signals and acceleration signals are collected; Fourier transforms are performed on the collected vibration force signals and acceleration signals to calculate the initial frequency response function curve; the initial frequency response function curve is smoothed using the averaging method of adjacent data points. The smoothing method using the centrally symmetric averaging method of adjacent data points can suppress the burr noise that easily occurs in micro-vibration tests, thereby effectively identifying the peak frequency; the natural frequency of the isolator under test can be accurately determined based on the smoothed initial frequency response function curve.

[0095] In addition, a metal helical tension spring is used to counteract gravity, and the natural frequency of the unloading mechanism is ensured to be much lower than the frequency of the vibration isolator under test, so that the unloading mechanism does not interfere with the test results.

[0096] like Figure 4As shown, this embodiment provides an electronic device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which are executed by the at least one processor to enable the at least one processor to perform the method steps described in the above embodiment.

[0097] This application provides a non-volatile computer storage medium storing computer-executable instructions that can perform the steps described in the above embodiments.

[0098] The following is for reference. Figure 4 The diagram illustrates a structural schematic of an electronic device suitable for implementing the embodiments of this application. The terminal devices in the embodiments of this application may include, but are not limited to, mobile terminals such as mobile phones, laptops, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), in-vehicle terminals (e.g., in-vehicle navigation terminals), and fixed terminals such as digital TVs and desktop computers. Figure 4 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0099] like Figure 4 As shown, the electronic device may include a processing unit (e.g., a central processing unit, a graphics processing unit, etc.) 401, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 402 or a program loaded from a storage device 408 into a random access memory (RAM) 403. The RAM 403 also stores various programs and data required for the operation of the electronic device. The processing unit 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0100] Typically, the following devices can be connected to I / O interface 405: input devices 406 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 407 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 408 including, for example, magnetic tapes, hard disks, etc.; and communication devices 409. Communication device 409 allows electronic devices to communicate wirelessly or wiredly with other devices to exchange data. Although Figure 4 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown. More or fewer devices may be implemented or have alternatively.

[0101] Specifically, according to embodiments of this application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device 409, or installed from a storage device 408, or installed from a ROM 402. When the computer program is executed by the processing device 401, it performs the functions defined in the methods of the embodiments of this application.

[0102] It should be noted that the computer-readable medium described above in this application can be a computer-readable signal medium, a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wires, optical fibers, RF (radio frequency), etc., or any suitable combination thereof.

[0103] The aforementioned computer-readable medium may be included in the aforementioned electronic device; or it may exist independently and not assembled into the electronic device.

[0104] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0105] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0106] The units described in the embodiments of this application can be implemented in software or hardware. The names of the units are not, in some cases, limiting the scope of the unit itself.

Claims

1. A method for testing the natural frequency of a micro-vibration isolator, characterized in that, include: The vibration isolator under test is fixed on the test platform, and the load mass block and the exciter are unloaded by gravity using a hanger and a gravity unloading mechanism to construct a test simulation environment. The gravity unloading mechanism includes a first unloading spring connected to the load mass block and a second unloading spring connected to the exciter. Vibration tests were conducted on the vibration isolator under test within the constructed test simulation environment. When the load mass block and the vibration isolator under test started to vibrate, vibration force signals and acceleration signals were collected. The collected vibration force and acceleration signals are subjected to Fourier transform to calculate the initial frequency response function curve. The initial frequency response function curve is smoothed by averaging adjacent data points. The natural frequency of the vibration isolator under test is determined based on the smoothed initial frequency response function curve.

2. The method for testing the natural frequency of a micro-vibration isolator according to claim 1, characterized in that, The gravity unloading process for the load mass block and vibrator using a hanger and gravity unloading mechanism includes: Multiple first unloading springs are symmetrically arranged on the upper surface of the load mass block, and the natural frequency of the first spring oscillator formed by the load mass block and the multiple first unloading springs is lower than the design value of the natural frequency of the vibration isolator under test. The relationship between the natural frequency of the first spring oscillator and the design value of the natural frequency of the vibration isolator under test is characterized by the following expression: Wherein, f0 represents the natural frequency design value of the vibration isolator under test; m1 represents the mass of the load mass block; n1 represents the number of first unloading springs; k1 represents the stiffness of a single first unloading spring; S represents the first adjustment coefficient of the natural frequency of the first spring oscillator relative to the design natural frequency of the vibration isolator, and the value of the first adjustment coefficient S is 1 / 5 to 1 / 10.

3. The method for testing the natural frequency of a micro-vibration isolator according to claim 1, characterized in that, The gravity unloading process for the load mass block and vibrator using a hanger and gravity unloading mechanism includes: Multiple second unloading springs are symmetrically arranged on the upper end face of the exciter, and the natural frequency of the second spring oscillator formed by the exciter and the multiple second unloading springs is lower than the design value of the natural frequency of the vibration isolator under test. The relationship between the natural frequency of the second spring oscillator and the design value of the natural frequency of the vibration isolator under test is characterized by the following expression: Wherein, f0 represents the natural frequency design value of the vibration isolator under test; m2 represents the mass of the load mass block; n2 represents the number of second unloading springs; k2 represents the stiffness of a single second unloading spring; S' represents the second adjustment coefficient of the natural frequency of the second spring oscillator relative to the design natural frequency of the vibration isolator, and the value of the second adjustment coefficient S' is 1 / 5 to 1 / 10.

4. The method for testing the natural frequency of a micro-vibration isolator according to claim 1, characterized in that, Further includes: The exciter is driven by a control cable to generate a sweep frequency excitation force, which is then applied to the load mass block and further transmitted to the vibration isolator under test, so that the vibration isolator under test and the load mass block vibrate. The actual sweep frequency excitation force output by the exciter is fed back to the vibration control acquisition module in real time using a measuring cable; The test platform is a ground rail in the mechanical testing laboratory or a transition plate installed on the ground rail.

5. The method for testing the natural frequency of a micro-vibration isolator according to claim 1, characterized in that, include: Acceleration signals during the vibration test are collected using at least one accelerometer sensor positioned on the upper surface of the load mass. Fourier transforms are performed on the collected vibration force and acceleration signals to obtain the Fourier transforms of the excitation force and acceleration. The ratio of the Fourier transforms of the excitation force and acceleration is then calculated to obtain the initial frequency response function curve of the vibration isolator under test.

6. The method for testing the natural frequency of a micro-vibration isolator according to claim 5, characterized in that, include: The initial frequency response function curve is smoothed using the averaging method of adjacent data points. The smoothed initial frequency response function curve is represented by the following expression: T1(ω i )=(T0(ω i-m )+…T0(ω i-2 )+T0(ω i-1 )+T0(ω i )+T0(ω i+1 )+T0(ω i+2 )+…+T0(ω i+m )) / (2m+1) Where, T1(ω i T0(ω) represents the initial frequency response function curve after smoothing, used to characterize the amplitude as a function of frequency. i ) represents the initial frequency response function curve without smoothing, ω i Let i represent the i-th frequency point, where i is 1, 2, ..., N; (2m+1) represents the number of frequency points for smoothing the initial frequency response function curve. Taking the i-th frequency point as the center, values ​​are taken on both sides of the center point, and the amplitude points corresponding to a total of 2m+1 frequency points are summed and then the average value is calculated.

7. A system for testing the natural frequency of a micro-vibration isolator, characterized in that, The method for testing the natural frequency of a micro-vibration isolator according to any one of claims 1 to 6 includes: The test platform is installed within a test simulation environment; The vibration isolator under test is fixedly installed on the test platform. A load mass block is connected to the vibration isolator under test and installed on the upper surface of the vibration isolator under test; A vibrator is connected to the load mass block and mounted on the upper end face of the load mass block; The hanger is located above the vibrator; The gravity unloading mechanism includes a first gravity unloading spring and a second gravity unloading spring. The first unloading spring is connected to the load mass block and the hanger, and the second unloading spring is connected to the vibrator and the hanger, so as to perform gravity unloading processing on the load mass block and the vibrator respectively.

8. The micro-vibration isolator natural frequency testing system according to claim 7, characterized in that, include: A first tension gauge is used to detect the tension required to unload the load mass block; A second force gauge is used to detect the force required to unload the exciter; An accelerometer is installed on the upper surface of the load mass block; as well as The control and acquisition module is used to acquire the actual frequency sweep excitation force output by the exciter and the acceleration output by the accelerometer.

9. The micro-vibration isolator natural frequency testing system according to claim 7, characterized in that, include: Multiple first unloading springs are symmetrically arranged on the upper surface of the load mass block, and the natural frequency of the first spring oscillator formed by the load mass block and the multiple first unloading springs is lower than the design value of the natural frequency of the vibration isolator under test. The relationship between the natural frequency of the first spring oscillator and the design value of the natural frequency of the vibration isolator under test is characterized by the following expression: Wherein, f0 represents the natural frequency design value of the vibration isolator under test; m1 represents the mass of the load mass block; n1 represents the number of first unloading springs; k1 represents the stiffness of a single first unloading spring; S represents the first adjustment coefficient of the natural frequency of the first spring oscillator relative to the design natural frequency of the vibration isolator, and the value of the first adjustment coefficient S is 1 / 5 to 1 / 10.

10. The micro-vibration isolator natural frequency testing system according to claim 7, characterized in that, include: The exciter is driven by a control cable to generate a sweep frequency excitation force, which is then applied to the load mass block and further transmitted to the vibration isolator under test, so that the vibration isolator under test and the load mass block vibrate. The actual sweep frequency excitation force output by the exciter is fed back to the vibration control acquisition module in real time using a measuring cable; The test platform is a ground rail in the mechanical testing laboratory or a transition plate installed on the ground rail.

Images