Frequency domain analysis method for micro-vibration environment of spacecraft

Abstract

The invention provides a frequency domain analysis method for a micro-vibration environment of a spacecraft. A disturbance source of the spacecraft is installed on a multi-component force measuring platform to measure time domain data of disturbance force and disturbance torque of a working state of the spacecraft; after the disturbance source is converted into frequency domain data, calculating a first transfer function of force and torque caused by a test tool of the multi-component force measurement platform in a non-working state of the disturbance source, and correcting the disturbance force and the disturbance torque based on the first transfer function; establishing a finite element model of the on-orbit operation state of the spacecraft; calculating a second transfer function from a disturbance source to a sensitive single machine based on the finite element model; and calculating the acceleration, displacement and angular displacement of the installation position of the sensitive single machine according to the corrected disturbance force, disturbance torque and a second transfer function. Therefore, the frequency domain response analysis of the micro-vibration environment of the spacecraft can be realized, and correction is carried out after the boundary condition difference of disturbance force measurement is considered.

Description

Technical Field

[0001] The present invention relates to the field of spacecraft technology, and in particular to a frequency domain analysis method for a spacecraft micro-vibration environment. Background Art

[0002] During the on-orbit operation of a spacecraft, the reciprocating motion of the spacecraft as a whole or locally with a small amplitude caused by the normal operation of on-board equipment (such as high-speed rotating parts such as momentum wheels, stepping parts such as solar wing drive mechanisms, and swinging parts such as infrared camera swing mirrors) or the tiny excitation of the space environment (such as thermally induced microvibrations caused by the spacecraft entering and exiting the earth's shadow) is called microvibration. Spacecraft sensitive to microvibration include remote sensing satellites, spacecraft with space telescopes and laser terminals. The microvibration environment on an on-orbit spacecraft will cause performance changes of sensitive payloads on these spacecraft, affecting the use of the spacecraft. With the increasing accuracy of payload performance on spacecraft, microvibration environment analysis has become an important simulation analysis for the overall design of spacecraft; however, the accuracy of spacecraft microvibration environment analysis is an issue that needs to be urgently addressed.

[0003] Micro-vibration environment analysis includes: disturbance source identification and disturbance force measurement, transfer function analysis, micro-vibration environment analysis at sensitive single machines, and analysis of the impact of micro-vibration environment on sensitive single machines. In the prior art, in terms of micro-vibration environment analysis, firstly, the time domain method is mainly used for analysis, that is, by measuring the time domain curve of the micro-vibration disturbance force of the disturbance source, loading it into the on-orbit finite element model for transient response analysis, obtaining the time domain curve of the micro-vibration environment, and then converting it into a frequency domain curve, such as the existing invention patent: A method for obtaining micro-vibration test conditions for aerospace vehicles (publication number: CN115455562A); secondly, the influence of the boundary conditions of the disturbance source disturbance force measurement is not considered. When measuring the disturbance force, the disturbance source is usually installed on a six-component force measurement platform through a tooling. Since the tooling is not completely rigid, the tooling has a certain influence on the measurement results of the disturbance force or torque, especially on the disturbance force or torque measurement of the disturbance source with a large mass, which needs to be corrected to obtain a more accurate disturbance force or torque curve.

[0004] Therefore, there is an urgent need for a frequency domain analysis method that can overcome the shortcomings of existing technologies and realize the spacecraft micro-vibration environment. Summary of the invention

[0005] The purpose of the present invention is to provide a frequency domain analysis method for a spacecraft micro-vibration environment, which can perform frequency domain response analysis on the spacecraft micro-vibration environment.

[0006] In order to achieve the above object, the present invention provides a frequency domain analysis method of a spacecraft micro-vibration environment, comprising the steps of:

[0007] Identify and determine the disturbance source of the spacecraft, and install the disturbance source on a multi-component force measurement platform to measure the time domain data of the disturbance force and disturbance torque of the working state of the disturbance source;

[0008] Converting the time domain data of the disturbance force and the disturbance torque into frequency domain data;

[0009] Calculating a first transfer function of the force and torque caused by the test fixture of the multi-component force measuring platform in a non-working state of the disturbance source, and correcting the disturbance force and the disturbance torque based on the first transfer function;

[0010] Establishing a finite element model of the spacecraft in orbit; wherein the finite element model at least includes the spacecraft structure cabin, the disturbance source and the sensitive unit;

[0011] Calculate a second transfer function from the disturbance source to the sensitive unit based on the finite element model;

[0012] According to the modified disturbance force, the disturbance torque and the second transfer function, the micro-vibration parameters at the installation location of the sensitive unit are calculated; wherein the micro-vibration parameters include acceleration, displacement and angular displacement.

[0013] Furthermore, the method of installing the disturbance source on a multi-component force measuring platform to measure the time domain data of the disturbance force and the disturbance torque of the working state of the disturbance source includes:

[0014] The disturbance source is installed on a six-component force measuring platform, the disturbance source is started, and the disturbance force time domain data and the disturbance torque time domain data of the disturbance source are measured through the six-component force measuring platform.

[0015] Further, the first transfer function for calculating the force and torque caused by the test fixture of the multi-component force measuring platform in the non-working state of the disturbance source includes:

[0016] Turning off the disturbance source, applying a tapping operation to the connection interface between the disturbance source and the test fixture of the multi-component force measuring platform, and collecting the multi-component force / torque measured by the multi-component force measuring platform and the tapping force / torque of the tapping operation;

[0017] The multi-component force / torque and the knocking force / torque are converted into frequency domain data, and a first transfer function of the force and torque caused by the test fixture of the multi-component force measuring platform is calculated based on the frequency domain data of the multi-component force / torque and the knocking force / torque.

[0018] Furthermore, the first transfer function is the ratio of the auto-power spectral density of the multi-component force / torque to the auto-power spectral density of the striking force / torque.

[0019] Furthermore, converting the time domain data of the disturbance force and the disturbance torque into frequency domain data comprises:

[0020] According to the time domain data of the disturbance force and the disturbance moment, the autopower spectrum density corresponding to the disturbance force and the disturbance moment is calculated.

[0021] Further, the disturbance force after correction is the product of the first transfer function and the disturbance force before correction; the disturbance moment after correction is the product of the first transfer function and the disturbance moment before correction.

[0022] Further, the calculating of the second transfer function from the disturbance source to the sensitive unit based on the finite element model includes:

[0023] Unit forces and moments are applied in sequence in multiple disturbance force directions and multiple disturbance moment directions at the root of the disturbance source in the finite element model, and a second transfer function from the disturbance source to the sensitive unit is calculated based on a frequency response analysis method.

[0024] Further, the multi-component force measuring platform is a six-component force measuring platform;

[0025] The acceleration of the sensitive unit in six directions at each installation point p is calculated based on the following formula:

[0026]

[0027] The displacement of the sensitive unit in six directions at each installation point p is calculated based on the following formula:

[0028]

[0029] Where k = 1, 2, 3 represent three directions; j represents the direction number, S j ′ (f) represents the modified disturbance force or disturbance moment, A jk (f)| p represents the set of acceleration transfer functions from the jth disturbance direction to the kth response direction of each installation point p at the sensitive unit, D jk (f)| p It represents the set of displacement transfer functions from the jth disturbance direction to the kth response direction of each installation point p at the sensitive unit.

[0030] Furthermore, the angular displacement of the sensitive unit at the installation point p1 and the installation point p2 is calculated based on the following formula:

[0031]

[0032] Among them, Lp12 represents the distance between mounting point p1 and mounting point p2, a(f)| p1 is the acceleration response of the sensitive unit at the installation point p1; a(f)| p2 is the acceleration response of the sensitive unit at the installation point p2; d(f)| p1 is the displacement response of the sensitive unit at the installation point p1; d(f)| p2 is the displacement response of the sensitive unit at the installation point p2.

[0033] The disturbance sources include a momentum wheel, a control moment gyroscope, a solar sail driving mechanism and an antenna rotating mechanism.

[0034] The frequency domain analysis method of the spacecraft micro-vibration environment described in the present invention transforms the time domain curves of the disturbance force and the disturbance torque into the frequency domain, and then performs the frequency domain analysis of the micro-vibration environment. The method can be applied to the micro-vibration environment analysis of all spacecrafts; it can also be applied to the analysis of all disturbance sources on the spacecraft; at the same time, the method of the present invention for calculating acceleration, displacement and angular displacement by using the transfer function from the disturbance force, the disturbance torque and the disturbance source to the sensitive single machine has universal applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flowchart of the steps of the frequency domain analysis method of the spacecraft micro-vibration environment provided by an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a test system used for the disturbance force / torque of the disturbance source in the frequency domain analysis method of the spacecraft micro-vibration environment provided in an embodiment of the present invention;

[0037] Figure 3a to Figure 3b A time domain and frequency domain curve diagram of the radial disturbance force of the reaction wheel obtained by the frequency domain analysis method of the spacecraft micro-vibration environment provided in one embodiment of the present invention;

[0038] Figure 4 This is a satellite in-orbit model diagram;

[0039] Figure 5a to Figure 5b Schematic diagrams of curves of the acceleration transfer function and the displacement transfer function of the frequency domain analysis method of the spacecraft micro-vibration environment provided by an embodiment of the present invention;

[0040] Figure 6 A schematic diagram showing the prediction results of the micro-vibration environment caused by the reaction wheel by applying the frequency domain analysis method of the spacecraft micro-vibration environment provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0042] It should be noted that references to "one embodiment", "embodiment", "example embodiment", etc. in this specification refer to the embodiment described, which may include specific features, structures or characteristics, but not every embodiment must include these specific features, structures or characteristics. In addition, such expressions do not refer to the same embodiment. Furthermore, when describing specific features, structures or characteristics in conjunction with an embodiment, whether or not there is an explicit description, it has been shown that it is within the knowledge of those skilled in the art to combine such features, structures or characteristics into other embodiments.

[0043] In addition, certain words are used in the specification and subsequent claims to refer to specific components or parts. Those with ordinary knowledge in the relevant field should understand that manufacturers can use different nouns or terms to refer to the same component or part. This specification and subsequent claims do not use differences in names as a way to distinguish components or parts, but use differences in the functions of components or parts as the criteria for distinction. "Including" and "including" mentioned throughout the specification and subsequent claims are open-ended terms and should be interpreted as "including but not limited to". In addition, the word "connected" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connection through other devices.

[0044] Figure 1 A frequency domain analysis method for a spacecraft micro-vibration environment provided by an embodiment of the present invention is shown, comprising the following steps:

[0045] S101: Identify and determine the disturbance source of the spacecraft, and install the disturbance source on a multi-component force measurement platform to measure the time domain data of the disturbance force and disturbance torque of the working state of the disturbance source. The working state of the disturbance source is specifically the running state at startup and after startup.

[0046] First, based on the design of the spacecraft, all disturbance sources on the spacecraft can be identified and determined. The disturbance sources are generally movable equipment, including but not limited to momentum wheels, control moment gyroscopes, solar sail drive mechanisms, and antenna rotation mechanisms.

[0047] After determining the disturbance sources, install each disturbance source on the multi-component force measurement platform, such as Figure 2As shown; this embodiment preferably adopts a six-component force measuring platform, the disturbance source is installed on the test fixture on the multi-component force measuring platform, and the multi-component force measuring platform is connected to the charge amplifier through a cable, and the charge amplifier is then connected to the LMS vibration control and data acquisition system, and finally connected to the computer; after all the disturbance sources are installed on the six-component force measuring platform, the disturbance source is started, and the disturbance force time domain data and the disturbance torque time domain data of the disturbance source are measured by the six-component force measuring platform, thereby obtaining the time domain data F(t) or M(t) of the disturbance force and disturbance torque of each disturbance source; in this embodiment, the radial disturbance force of the reaction wheel is taken as an example, and the curve of the corresponding time domain data is measured as shown Figure 3a shown.

[0048] S102: Convert the time domain data of the disturbance force and the disturbance torque into frequency domain data.

[0049] In specific implementation, step S102 includes: calculating the auto-power spectral density corresponding to the disturbance force and disturbance moment according to the time domain data of the disturbance force and disturbance moment. In this embodiment, the auto-power spectral density of the disturbance force and disturbance moment is assumed to be S j (f), (j=1,2,…,6); when j=1~3, S j (f) represents the disturbance force in three directions. When j=4-6, S j (f) represents the disturbance torque in three directions, and f represents the frequency.

[0050] Combining the above examples, Figure 3a The curve after the time domain data is converted into frequency domain data is as follows Figure 3b shown.

[0051] S103: Calculate a first transfer function of the force and torque caused by the test fixture of the multi-component force measuring platform in a non-working state of the disturbance source, and correct the disturbance force and the disturbance torque based on the first transfer function.

[0052] The calculation of the first transfer function of the force and torque caused by the test fixture of the multi-component force measuring platform when the disturbance source is in the non-working state of the present embodiment includes: shutting down the disturbance source, applying a tapping operation to the connection interface between the disturbance source and the test fixture of the multi-component force measuring platform, and collecting the multi-component force / torque measured by the multi-component force measuring platform and the tapping force / torque of the tapping operation; converting the multi-component force / torque and the tapping force / torque into frequency domain data, and calculating the first transfer function of the force and torque caused by the test fixture of the multi-component force measuring platform based on the frequency domain data of the multi-component force / torque and the tapping force / torque.

[0053] In the specific implementation, the disturbance source on the six-component force measuring platform is turned off. When the disturbance source is not working, a hammer is used to strike a position on the connection interface between the disturbance source and the test fixture that is easy to implement the striking operation. The force or torque applied is F0(t). The six-component force measured by the six-component force measuring platform and the force value F0 applied by the hammer are collected. ′ (t), and then calculate the auto-power spectral density S0(f) and S0 ′ (f), and the transfer function of the force and torque caused by the test fixture can be calculated by the following formula:

[0054] That is, the first transfer function is the ratio of the auto-power spectral density of the multi-component force / torque to the auto-power spectral density of the striking force / torque.

[0055] Furthermore, the corrected disturbance force is the product of the first transfer function and the disturbance force before correction; and the corrected disturbance torque is the product of the first transfer function and the disturbance torque before correction.

[0056] S j (f) represents the disturbance force / disturbance torque before correction, and the disturbance force / disturbance torque corrected based on the first transfer function is:

[0057] S j ′ (f)=H0(f)S j (f).

[0058] S104: Establish a finite element model of the spacecraft in orbit; wherein the finite element model at least includes the spacecraft structure cabin, the disturbance source and the sensitive unit, and further includes major large equipment. As shown in the figure, there is no logical sequence between this step and the aforementioned steps S101 to S103, and this step can be performed simultaneously with the aforementioned steps, or before or after the aforementioned steps. Figure 4 The finite element model preferably established in this embodiment is shown.

[0059] S105: Calculate a second transfer function from the disturbance source to a sensitive unit based on the finite element model.

[0060] In specific implementation, step S105 includes: applying unit force and torque in turn through multiple disturbance force directions and multiple disturbance torque directions at the root of the disturbance source in the finite element model, and calculating the second transfer function from the disturbance source to the sensitive unit based on the frequency response analysis method. In this embodiment, the three disturbance force directions at the root of the disturbance source in the finite element model are F x , F y , F z And the three disturbance moments are M x , M y , Mz ; Unit force and torque are applied to the above six directions, and the second transfer function from the disturbance source to the sensitive unit is calculated by the frequency response analysis method; including the acceleration transfer function (A) from the jth disturbance direction of the disturbance source (j = 1, 2, ..., 6; j = 1 to 3 represents the three-directional disturbance force, j = 4 to 6 represents the three-directional disturbance torque) to the kth response direction of each installation point p at the sensitive unit jk ) and displacement transfer function (D jk ), denoted as A jk (f)| p and D jk (f)| p In this embodiment, the curves of the acceleration transfer function and displacement transfer function from the reaction wheel disturbance force to the sensitive single machine mounting surface are as follows: Figure 5a to Figure 5b shown.

[0061] S106: Calculate the micro-vibration parameters at the installation location of the sensitive unit according to the corrected disturbance force, disturbance moment and the second transfer function; wherein the micro-vibration parameters include acceleration, displacement and angular displacement. That is, the acceleration, displacement and angular displacement at the installation location of the sensitive unit are calculated using the disturbance force and disturbance moment corrected in step S103 and the second transfer function calculated in step S105.

[0062] In a specific embodiment, the multi-component force measuring platform is a six-component force measuring platform;

[0063] The acceleration of the sensitive unit in six directions at each installation point p is calculated based on the following formula:

[0064]

[0065] The displacement of the sensitive unit in six directions at each installation point p is calculated based on the following formula:

[0066]

[0067] Where k = 1, 2, 3 represent three directions; j represents the direction number, S j ′ (f) represents the modified disturbance force or disturbance moment, A jk (f)| p represents the set of acceleration transfer functions from the jth disturbance direction to the kth response direction of each installation point p at the sensitive unit, D jk (f)| p It represents the set of displacement transfer functions from the jth disturbance direction to the kth response direction of each installation point p at the sensitive unit.

[0068] Substituting k=1, 2, 3 into the above equation, the acceleration response of the sensitive unit at the installation point p is calculated as:

[0069]

[0070] The displacement response of a certain installation point p of a sensitive single machine is calculated as:

[0071]

[0072] Furthermore, the angular displacement of the sensitive unit at the installation point p1 and the installation point p2 is calculated based on the following formula:

[0073]

[0074] Among them, L p12 represents the distance between mounting point p1 and mounting point p2, a(f)| p1 is the acceleration response of the sensitive unit at the installation point p1; a(f)| p2 is the acceleration response of the sensitive unit at the installation point p2; d(f)| p1 is the displacement response of the sensitive unit at the installation point p1; d(f)| p2 is the displacement response of the sensitive unit at the installation point p2.

[0075] The reaction wheel is used as the disturbance source and the method described in this embodiment is used to analyze the micro-vibration environment prediction results caused by the reaction wheel. Figure 6 shown.

[0076] In summary, the frequency domain analysis method of the spacecraft micro-vibration environment described in the present invention is to install the disturbance source of the spacecraft on a multi-component force measuring platform to measure the time domain data of the disturbance force and disturbance torque of its working state; after converting it into frequency domain data, calculate the first transfer function of the force and torque caused by the test fixture of the multi-component force measuring platform in the non-working state of the disturbance source, and correct the disturbance force and disturbance torque based on the first transfer function; establish a finite element model of the spacecraft on-orbit operation state; calculate the second transfer function from the disturbance source to the sensitive unit based on the finite element model; calculate the acceleration, displacement and angular displacement of the installation point of the sensitive unit according to the corrected disturbance force, disturbance torque and second transfer function. In this way, the present invention can realize the frequency domain response analysis of the spacecraft micro-vibration environment, and make corrections after considering the boundary condition differences of the disturbance force measurement.

[0077] It should be noted that the present application can be implemented in software and / or a combination of software and hardware, for example, can be implemented using an application specific integrated circuit (ASIC), a general purpose computer or any other similar hardware device. In one embodiment, the software program of the present application can be executed by a processor to implement the above steps or functions. Similarly, the software program of the present application (including relevant data structures) can be stored in a computer-readable recording medium, for example, a RAM memory, a magnetic or optical drive or a floppy disk and similar devices. In addition, some steps or functions of the present application can be implemented using hardware, for example, as a circuit that cooperates with a processor to perform each step or function.

[0078] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A frequency domain analysis method for spacecraft micro-vibration environment, characterized in that: Includes steps: Identify and determine the disturbance source of the spacecraft, and install the disturbance source on a multi-component force measurement platform to measure the time domain data of the disturbance force and disturbance torque of the working state of the disturbance source; Converting the time domain data of the disturbance force and the disturbance torque into frequency domain data; Calculating a first transfer function of the force and torque caused by the test fixture of the multi-component force measuring platform in a non-working state of the disturbance source, and correcting the disturbance force and the disturbance torque based on the first transfer function; Establishing a finite element model of the spacecraft in orbit; wherein the finite element model at least includes the spacecraft structure cabin, the disturbance source and the sensitive unit; Calculate a second transfer function from the disturbance source to the sensitive unit based on the finite element model; According to the modified disturbance force, the disturbance torque and the second transfer function, the micro-vibration parameters at the installation location of the sensitive unit are calculated; wherein the micro-vibration parameters include acceleration, displacement and angular displacement.

2. The frequency domain analysis method of spacecraft micro-vibration environment according to claim 1, characterized in that: The time domain data of the disturbance force and the disturbance torque of the working state of the disturbance source measured by installing the disturbance source on the multi-component force measuring platform includes: The disturbance source is installed on a six-component force measuring platform, the disturbance source is started, and the disturbance force time domain data and the disturbance torque time domain data of the disturbance source are measured through the six-component force measuring platform.

3. The frequency domain analysis method of spacecraft micro-vibration environment according to claim 1, characterized in that: The first transfer function for calculating the force and torque caused by the test fixture of the multi-component force measuring platform in the non-working state of the disturbance source includes: Turning off the disturbance source, applying a tapping operation to the connection interface between the disturbance source and the test fixture of the multi-component force measuring platform, and collecting the multi-component force / torque measured by the multi-component force measuring platform and the tapping force / torque of the tapping operation; The multi-component force / torque and the knocking force / torque are converted into frequency domain data, and a first transfer function of the force and torque caused by the test fixture of the multi-component force measuring platform is calculated based on the frequency domain data of the multi-component force / torque and the knocking force / torque.

4. The frequency domain analysis method of spacecraft micro-vibration environment according to claim 3, characterized in that: The first transfer function is a ratio of the auto-power spectral density of the multi-component force / torque to the auto-power spectral density of the striking force / torque.

5. The frequency domain analysis method of spacecraft micro-vibration environment according to claim 1, characterized in that: The converting the time domain data of the disturbance force and the disturbance torque into frequency domain data comprises: According to the time domain data of the disturbance force and the disturbance moment, the autopower spectrum density corresponding to the disturbance force and the disturbance moment is calculated.

6. The frequency domain analysis method of spacecraft micro-vibration environment according to claim 1, characterized in that: The corrected disturbance force is the product of the first transfer function and the disturbance force before correction; the corrected disturbance torque is the product of the first transfer function and the disturbance torque before correction.

7. The frequency domain analysis method of spacecraft micro-vibration environment according to claim 1, characterized in that: The calculating, based on the finite element model, a second transfer function from the disturbance source to the sensitive unit comprises: Unit forces and moments are applied in sequence in multiple disturbance force directions and multiple disturbance moment directions at the root of the disturbance source in the finite element model, and a second transfer function from the disturbance source to the sensitive unit is calculated based on a frequency response analysis method.

8. The frequency domain analysis method of spacecraft micro-vibration environment according to claim 1, characterized in that: The multi-component force measuring platform is a six-component force measuring platform; The acceleration of the sensitive unit in six directions at each installation point p is calculated based on the following formula: The displacement of the sensitive unit in six directions at each installation point p is calculated based on the following formula: Where k = 1, 2, 3 represent three directions; j represents the direction number, S j ′ (f) represents the modified disturbance force or disturbance moment, A jk (f)| p represents the set of acceleration transfer functions from the jth disturbance direction to the kth response direction of each installation point p at the sensitive unit, D jk (f)| p It represents the set of displacement transfer functions from the jth disturbance direction to the kth response direction of each installation point p at the sensitive unit.

9. The frequency domain analysis method of spacecraft micro-vibration environment according to claim 8, characterized in that: The angular displacement of the sensitive unit at the mounting point p1 and the mounting point p2 is calculated based on the following formula: Among them, L p12 represents the distance between mounting point p1 and mounting point p2, a(f)| p1 is the acceleration response of the sensitive unit at the installation point p1; a(f)| p2 is the acceleration response of the sensitive unit at the installation point p2; d(f)| p1 is the displacement response of the sensitive unit at the installation point p1; d(f)| p2 is the displacement response of the sensitive unit at the installation point p2.

10. The frequency domain analysis method of spacecraft micro-vibration environment according to any one of claims 1 to 9, characterized in that: The disturbance sources include a momentum wheel, a control moment gyroscope, a solar sail driving mechanism and an antenna rotating mechanism.

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