Equivalent calculation method for three-axis vibration test conditions of spacecraft

Abstract

The invention relates to a spacecraft three-axis vibration test condition equivalent calculation method, which comprises the following steps: constructing a three-axis vibration dynamic equation and solving a three-axis vibration dynamic response based on a traditional vibration dynamic theory, and obtaining the three-axis vibration dynamic response in a frequency domain through frequency domain conversion; through three-axis simulation analysis and single-axis simulation analysis, dynamic responses under a three-axis vibration boundary and a single-axis vibration boundary are obtained; and establishing a difference value minimization criterion according to the dynamic response under the three-axis vibration boundary and the uniaxial vibration boundary, and solving an optimization problem by taking the difference value minimization as an optimization target and the three-axis vibration condition as an optimization variable. According to the method, the problem of non-real simulation of the active section spacecraft vibration environment of an existing single-axis vibration test method is solved, the multi-axis coupling real state of the active section vibration environment is fully considered, the three-axis vibration test condition is reasonably formulated, the obtained result better conforms to the real situation, and the engineering applicability is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of spacecraft vibration test, and in particular to a method for equivalent calculation of spacecraft triaxial vibration test conditions. Background Art

[0002] During the launch phase, spacecraft need to withstand a complex mechanical environment, which is mainly manifested in the form of vibration and noise. Ground vibration testing is an important task in the satellite development process. Vibration test benches can be used to simulate the mechanical environment of spacecraft in the rocket fairing to assess the environmental adaptability and reliability of the product. At present, the vibration test process mostly uses single-axis separate excitation. The test conditions envelope the rocket telemetry data and leave corresponding margins. The real environment of the spacecraft is multi-axis concurrent and has multi-degree-of-freedom coupling effects. Therefore, the existing test methods and processes are difficult to truly reflect the mechanical environment of the spacecraft, and there is a possibility of distortion. In addition, the test method of single-axis separate excitation will result in a longer time and lower development efficiency.

[0003] Therefore, how to perform equivalent calculations of spacecraft triaxial vibration test conditions to make the test results more consistent with the actual situation and improve the engineering application value of the test results has become an important topic in the field of spacecraft vibration test technology. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an equivalent calculation method for spacecraft three-axis vibration test conditions, which solves the problem of non-realistic simulation of the active section spacecraft vibration environment of the existing uniaxial vibration test method, and has the characteristics of strong authenticity of test results and strong engineering applicability.

[0005] To achieve the above-mentioned purpose, the present invention provides a method for calculating the equivalent conditions of a spacecraft triaxial vibration test, comprising the following steps:

[0006] Step S1, based on the traditional vibration dynamics theory, construct the three-axis vibration dynamics equation and solve the three-axis vibration dynamics response, and obtain the three-axis vibration dynamics response in the frequency domain through frequency domain conversion;

[0007] Step S2, based on the three-axis dynamic vibration equation and solution method, combined with the finite element analysis method, complete the three-axis simulation analysis to obtain the dynamic response under the three-axis vibration boundary;

[0008] Step S3, based on the traditional uniaxial vibration equation and solution method, complete the uniaxial simulation analysis to obtain the dynamic response under the uniaxial vibration boundary;

[0009] Step S4, according to the dynamic response under the triaxial vibration boundary and the uniaxial vibration boundary, establish the difference minimization criterion, take the difference minimization as the optimization goal, and the triaxial vibration condition as the optimization variable to complete the solution of the optimization problem and complete the equivalent calculation of the triaxial vibration test condition.

[0010] According to a technical solution of the present invention, in step S1, the triaxial vibration dynamic response in the frequency domain is:

[0011]

[0012] Among them, G xyz (f) is the triaxial vibration dynamic response in the frequency domain, H i (f) is the frequency response function matrix of structural foundation excitation and structural dynamic response, H i The conjugate transposed matrix of (f), G ij (f) is the structural base excitation, where:

[0013]

[0014] Among them, γ ij and θ ij is the correlation coefficient and phase difference under different axial basic excitation spectra, G ii and G jj Both represent the basic excitation spectra of the coaxial structure.

[0015] According to a technical solution of the present invention, the dynamic response is a force response at the root of the structure, an acceleration response at a key position of the equipment, or a displacement response.

[0016] According to a technical solution of the present invention, in step S2, a triaxial simulation analysis is performed by a finite element analysis method to obtain the structural dynamic response under triaxial excitation conditions and express it as Resp triaxial .

[0017] According to a technical solution of the present invention, in step S3, a uniaxial simulation analysis is performed in the X, Y, and Z directions by a finite element analysis method to obtain the structural dynamic response under uniaxial excitation conditions and express it as Resp uniaxial .

[0018] According to a technical solution of the present invention, in step S4, it specifically includes:

[0019] The finite element model is parameterized, the three-axis acceleration in the sinusoidal vibration condition and the power spectrum density in the random vibration condition are used as optimization variables, the minimum difference between the three-axis and single-axis responses is used as the optimization target, and the optimization process is established. The specific optimization formula is expressed as follows:

[0020]

[0021] Among them, Acc x ,Acc y ,Acc z is the triaxial acceleration under sinusoidal vibration conditions; Psd xyz is the power spectrum density under random vibration conditions, find means seek, min means minimum, and st means constraint condition.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention creatively proposes an equivalent calculation method for three-axis vibration test conditions of spacecraft, which can simulate the vibration environment of the active section of the spacecraft more realistically to avoid the problem of "under-testing" or "over-testing"; the present invention can save the cost of spacecraft vibration testing and shorten the development cycle by rationally formulating the three-axis vibration test conditions of the spacecraft, and has engineering application value and economic value; the present invention derives the three-axis vibration dynamics equation, which provides a basis for the transformation and solution of subsequent mathematical optimization problems. The present invention solves the problem of non-realistic simulation of the active section spacecraft vibration environment of the existing single-axis vibration test method, fully considers the real state of multi-axis coupling of the active section vibration environment, and rationally formulates the three-axis vibration test conditions. The results obtained are more in line with the actual situation and have stronger engineering applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 A schematic diagram showing a principle diagram of an equivalent calculation method for a spacecraft triaxial vibration test condition provided in the present invention;

[0026] Figure 2 A specific flow chart schematically showing a method for calculating equivalent conditions of a spacecraft triaxial vibration test according to an embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of the structure of a spacecraft in one embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of a three-axis sinusoidal vibration test condition optimization process in one embodiment of the present invention;

[0029] Figure 5is a schematic diagram of a triaxial random vibration test condition optimization process in one embodiment of the present invention;

[0030] Figure 6 It is a schematic diagram comparing the triaxial random vibration test conditions and the uniaxial test conditions in one embodiment of the present invention. DETAILED DESCRIPTION

[0031] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0032] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0033] like Figure 1 As shown, the present invention proposes an equivalent calculation method for the three-axis vibration test conditions of spacecraft, abstracts the engineering problem into a mathematical optimization problem, and then uses a global optimization algorithm to complete the solution. First, based on the traditional dynamics theory, the theoretical derivation of the three-axis vibration dynamic response is completed; secondly, based on the above theoretical derivation and the finite element method, the single-axis and three-axis dynamic response solutions are carried out; thirdly, the engineering problem is converted into a mathematical optimization problem, an optimization model is established, and a global optimization algorithm is introduced to solve the optimization problem; finally, the three-axis vibration test conditions are obtained. Based on this, technical support can be provided for the three-axis vibration test of spacecraft.

[0034] like Figure 2 As shown, a method for calculating equivalent conditions of a spacecraft triaxial vibration test of the present invention comprises the following steps:

[0035] Step S1, based on the traditional vibration dynamics theory, construct the three-axis vibration dynamics equation and solve the three-axis vibration dynamics response, and obtain the three-axis vibration dynamics response in the frequency domain through frequency domain conversion;

[0036] The triaxial vibration dynamic response in the frequency domain is:

[0037]

[0038] Among them, G xyz (f) is the triaxial vibration dynamic response in the frequency domain, H i(f) is the frequency response function matrix of structural foundation excitation and structural dynamic response, H i The conjugate transposed matrix of (f), G ij (f) for structural base excitation;

[0039]

[0040] Among them, γ ij and θ ij is the correlation coefficient and phase difference under different axial basic excitation spectra, G ii and G jj Both represent the basic excitation spectra of the coaxial structure.

[0041] Step S2, based on the triaxial vibration dynamics equation and solution method, combined with the finite element analysis method, complete the triaxial simulation analysis to obtain the dynamic response under the triaxial vibration boundary;

[0042] The triaxial simulation analysis is carried out by the finite element analysis method to obtain the structural dynamic response under triaxial excitation conditions and express it as Resp triaxial

[0043] Step S3, based on the traditional uniaxial vibration equation and solution method, complete the uniaxial simulation analysis to obtain the dynamic response under the uniaxial vibration boundary;

[0044] Through the finite element analysis method, uniaxial simulation analysis in the X, Y, and Z directions is performed to obtain the structural dynamic response under uniaxial excitation conditions and express it as Resp uniaxial .

[0045] The dynamic response under the triaxial vibration boundary and the dynamic response under the uniaxial vibration boundary can be the force response of the structure root, the acceleration response or the displacement response of the key position of the equipment, which can be selected according to the test conditions of the simulation analysis. The dynamic response under the triaxial vibration boundary and the uniaxial vibration boundary is obtained and compared as a basis.

[0046] Step S4, according to the dynamic response under the triaxial vibration boundary and the uniaxial vibration boundary, a difference minimization criterion is established, and the difference minimization is taken as the optimization goal, the triaxial vibration condition is taken as the optimization variable, the optimization problem is solved, and the equivalent calculation of the triaxial vibration test condition is completed.

[0047] The finite element model is parameterized, the three-axis acceleration in the sinusoidal vibration condition and the power spectrum density in the random vibration condition are used as optimization variables, the minimum difference between the three-axis and single-axis responses is used as the optimization target, and the optimization process is established. The specific optimization formula is expressed as follows:

[0048]

[0049] Among them, find means to seek, min means the minimum value, and st means the constraint condition; Acc x ,Acc y ,Acc z is the triaxial acceleration under sinusoidal vibration conditions; Psd xyz It is the power spectral density in random vibration conditions. The goal is to minimize the difference between the three-axis and single-axis responses. The constraint condition is that the difference between the three-axis and single-axis is greater than or equal to 0. The response can be the root force of the spacecraft, the acceleration or displacement of the key position of the equipment.

[0050] By introducing a global optimization algorithm, the above optimization problem is solved and finally the optimal triaxial vibration test conditions that meet the conditions are obtained to achieve the equivalent formulation of triaxial vibration test conditions.

[0051] In order to more fully understand the characteristics of the invention and its applicability to engineering practice, the present invention is directed to Figure 2 The proposed spacecraft structure is shown in the figure to solve the triaxial vibration test conditions. The structure adopts a box-plate structure. The size of the whole satellite structure is about 990mm (length) 900mm (width) 1990mm (height), the thickness of the cabin plate is 4mm, the thickness of the bearing tube is 2mm, and the material is aluminum alloy. The thickness of the camera barrel is 3mm. The uniaxial sinusoidal vibration environment conditions are shown in Table 1, and the uniaxial random vibration conditions are shown in Table 2.

[0052] Table 1 Satellite sinusoidal vibration test conditions

[0053]

[0054] Table 2 Satellite random vibration test conditions

[0055]

[0056] This embodiment uses the optimization model proposed in the present invention to build optimization processes for three-axis sinusoidal and random vibration test conditions. In sinusoidal vibration, the three-axis acceleration is used as a variable, and in random vibration, the three-axis power spectrum density is used as a variable. In all vibration tests, the minimum difference between the single-axis response and the three-axis response is used as the goal to solve the optimization problem. The iterative process of sinusoidal optimization is as follows: Figure 4 As shown, curve a represents the axial force difference F1, and curve b represents the shear force difference F2; the random iterative optimization process is shown in Figure 5 As shown, curve c represents the axial force difference F1, curve d represents the shear force difference F2, the triaxial sinusoidal optimization conditions are shown in Table 3, the triaxial random optimization conditions are shown in Table 4, and the comparison with the uniaxial random conditions is shown in Figure 6 .

[0057] Table 3 Triaxial sine test conditions

[0058]

[0059] Table 4 Triaxial random vibration test conditions

[0060]

[0061] It should be noted that the above is a preferred embodiment of the present invention. It should be pointed out that although the preferred embodiment of the present invention has been described, once the basic creative concept of the present invention is known, a number of improvements and modifications can be made by a person skilled in the art without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the embodiments of the present invention.

Claims

1. A method for equivalent calculation of spacecraft triaxial vibration test conditions, characterized in that: The following steps are involved: Step S1, based on the traditional vibration dynamics theory, construct the three-axis vibration dynamics equation and solve the three-axis vibration dynamics response, and obtain the three-axis vibration dynamics response in the frequency domain through frequency domain conversion; Step S2, based on the triaxial vibration dynamics equation and solution method, combined with the finite element analysis method, complete the triaxial simulation analysis to obtain the dynamic response under the triaxial vibration boundary; Step S3, based on the traditional uniaxial vibration equation and solution method, complete the uniaxial simulation analysis to obtain the dynamic response under the uniaxial vibration boundary; Step S4, according to the dynamic response under the triaxial vibration boundary and the uniaxial vibration boundary, a difference minimization criterion is established, and the difference minimization is taken as the optimization goal, the triaxial vibration condition is taken as the optimization variable, the optimization problem is solved, and the equivalent calculation of the triaxial vibration test condition is completed.

2. The spacecraft triaxial vibration test condition equivalent calculation method according to claim 1 is characterized in that: In step S1, the triaxial vibration dynamic response in the frequency domain is: Among them, G xyz (f) is the triaxial vibration dynamic response in the frequency domain, H i (f) is the frequency response function matrix of structural foundation excitation and structural dynamic response, H i The conjugate transposed matrix of (f), G ij (f) is the structural base excitation, where: Among them, γ ij and θ ij is the correlation coefficient and phase difference under different axial basic excitation spectra, G ii and G jj Both represent the basic excitation spectra of the coaxial structure.

3. The spacecraft triaxial vibration test condition equivalent calculation method according to claim 1 is characterized in that: The dynamic response is a force response at the root of the structure, an acceleration response at a key position of the equipment, or a displacement response.

4. The spacecraft triaxial vibration test condition equivalent calculation method according to claim 1 is characterized in that: In step S2, a triaxial simulation analysis is performed by a finite element analysis method to obtain the structural dynamic response under triaxial excitation conditions and express it as Resp triaxial .

5. The spacecraft triaxial vibration test condition equivalent calculation method according to claim 4 is characterized in that: In step S3, a uniaxial simulation analysis is performed in the X, Y, and Z directions by a finite element analysis method to obtain the structural dynamic response under uniaxial excitation conditions and express it as Resp uniaxial .

6. The spacecraft triaxial vibration test condition equivalent calculation method according to claim 5 is characterized in that: In the step S4, it specifically includes: The finite element model is parameterized, the three-axis acceleration in the sinusoidal vibration condition and the power spectrum density in the random vibration condition are used as optimization variables, the minimum difference between the three-axis and single-axis responses is used as the optimization target, and the optimization process is established. The specific optimization formula is expressed as follows: Among them, Acc x ,Acc y ,Acc z is the triaxial acceleration under sinusoidal vibration conditions; Psd xyz is the power spectrum density under random vibration conditions, find means seek, min means minimum, and st means constraint condition.

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