Method and system for measuring size and morphological characteristics of pressure-sensitive structure of arc-shaped bottom of rocket rupture diaphragm

Abstract

The invention provides an effective measurement method and system for the size and morphology characteristics of an arc-shaped bottom pressure-sensitive structure of a rupture diaphragm. The method comprises the steps of high-precision measurement of the pressure-sensitive structure, data processing and calculation of the structure size and the surface morphology characteristics. According to the method, confocal microscopic measurement is carried out on the rupture diaphragm arc-bottom pressure-sensitive structure, multilayer two-dimensional wavelet decomposition and reconstruction are carried out according to measured point cloud data, curved surface fitting is carried out on low-frequency reconstructed point cloud, the depth of the pressure-sensitive structure is determined, and morphological feature calculation is carried out on high-frequency reconstructed point cloud. And complete and accurate measurement of the size and the morphology of the pressure-sensitive structure of the diaphragm is realized.

Description

Technical Field

[0001] The present invention relates to the field of valve technology for a launch vehicle booster delivery system, and specifically, to a method and system for measuring the size and morphological characteristics of a pressure-sensitive structure of an arc-shaped bottom of a ruptured diaphragm of a rocket, and more specifically, to an effective method and system for measuring the size and morphological characteristics of a pressure-sensitive structure of an arc-shaped bottom of a ruptured diaphragm in a launch vehicle booster delivery system. Background Art

[0002] The rupture diaphragm is one of the key core components of the launch vehicle's booster delivery system. It is mainly used in the booster pipeline to isolate the tank from the booster cylinder before the cylinder gas is pressurized. After the rocket engine is ignited, the pressure reducing valve opens, and the upstream booster gas enters the pipeline. The diaphragm is subjected to the gas pressure gradually rising to the target pressure until it ruptures, thus achieving conduction of the booster pipeline. The rupture diaphragm is a typical pressure-sensitive element, and its accurate rupture at the target pressure directly affects the normal operation of the rocket's booster delivery system. Due to the change in material properties caused by strain strengthening, the traditional stamped diaphragm has insufficient stability in the rupture pressure difference of the diaphragm. After production is completed, a large number of sampling and destructive testing are required to ensure that the rupture pressure difference of the ruptured diaphragm is within the specified range.

[0003] The use of ultrafast laser processing technology has little effect on the mechanical properties of the diaphragm substrate, making it possible to predict the rupture pressure difference based on the size of the diaphragm piezoresistance structure. However, with the improvement of processing efficiency, the surface morphology of the diaphragm piezoresistance structure changes significantly in the rapid laser processing mode, and the surface roughness Sa can reach 7-40um, which has a significant impact on the rupture performance of the model. Therefore, accurately measuring the size and surface morphology characteristics of the diaphragm piezoresistance structure is crucial to accurately evaluate the performance of the ruptured diaphragm. Usually, the diaphragm piezoresistance structure is an inverted trapezoid as a whole, with a small bottom width of generally 30-60um, and due to the Gaussian distribution of the spot energy, scanning method, scanning spacing and other factors in laser processing, the bottom of the piezoresistance structure has a certain curvature, and the roughness of each area is significantly different, which makes it difficult to measure the size and morphology of the diaphragm piezoresistance structure.

[0004] At present, the main methods for measuring the size of the diaphragm pressure-sensitive structure are: Method 1 uses wire cutting and other methods to cut the diaphragm in the direction perpendicular to the pressure-sensitive structure and directly measure the depth of the pressure-sensitive structure. This measurement method is a destructive measurement, and the diaphragm cannot be used after the measurement. Method 2 uses contact measurement (such as patents: CN108955614A, CN108195698A, CN204228521U) to obtain the depth of the pressure-sensitive structure. Limited by the size of the measuring head and the measurement method, the contact measurement cannot fully measure the bottom morphology of the pressure-sensitive structure. In addition, considering the concave and convex morphology and surface roughness of the laser-processed parts, the depth of the pressure-sensitive structure obtained by contact measurement has a certain randomness. Method 3 uses a laser displacement sensor to measure the depth of the pressure-sensitive structure. Due to the structural depth, the laser spot of the displacement sensor cannot be too small, generally 30um, which is close to the bottom width of the diaphragm pressure-sensitive structure, making the displacement sensor insufficient in resolving the details of the bottom morphology of the pressure-sensitive structure, and the actual use effect is not good. In summary, the above methods are unable to accurately obtain the exact size and morphological characteristics of the diaphragm pressure-sensitive structure, and a more effective measurement method is needed. Summary of the invention

[0005] In view of the defects in the prior art, the purpose of the present invention is to provide a method and system for measuring the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of a rocket rupture diaphragm.

[0006] According to the present invention, a method for determining the size and morphological characteristics of a rocket rupture diaphragm arc bottom pressure-sensitive structure comprises:

[0007] Step S1: measuring the ruptured diaphragm pressure-sensitive structure horizontally placed on a measuring workbench based on laser confocal microscopy to obtain three-dimensional measurement point cloud data;

[0008] Step S2: performing two-dimensional discrete wavelet multi-layer decomposition on the obtained three-dimensional measurement point cloud data;

[0009] Step S3: reconstruct the pressure-sensitive structure point cloud features using the decomposed data to obtain low-frequency point cloud data and high-frequency point cloud data;

[0010] Step S4: Use surface fitting to obtain the height of the lowest point of the surface for the low-frequency point cloud data, calculate the height difference between the height of the lowest point of the surface and the plane of the membrane at the top of the pressure-sensitive structure, and obtain the depth dimension of the pressure-sensitive structure;

[0011] Step S5: Calculate the surface roughness based on the high-frequency point cloud data to obtain the morphological characteristics of the pressure-sensitive structure.

[0012] Preferably, step S2 comprises:

[0013]

[0014] Among them, j represents the scale parameter, k = (k1, k2) represents the translation parameter, l represents the direction parameter, ψ j,k,l (m,n) is a discrete two-dimensional wavelet function, which is obtained by transforming the one-dimensional wavelet function ψ(m) by scale j and direction l; W f (j,k,l) ​​represents the information obtained after two-dimensional wavelet transform.

[0015] Preferably, step S3 comprises:

[0016] f(x,y)≈d1+...+d N +f N

[0017] Among them, d1...d N is the high frequency part, f N It is the low frequency part.

[0018] Preferably, the step S4 comprises:

[0019]

[0020] Among them, a, b, c, P, Q are the parameters to be fitted;

[0021] The lowest point height of the pressure-sensitive structure is calculated based on the fitting parabola. The calculation formula is as follows

[0022]

[0023] The height of the top diaphragm plane of the pressure-sensitive structure is taken as the reference value, then z min The absolute value of is the depth of the pressure-sensitive structure.

[0024] Preferably, step S5 comprises:

[0025]

[0026] Among them, Δx represents the micro-element width in the x direction, Δy represents the micro-element width in the y direction, z(x,y) represents the z coordinate of the point cloud with horizontal and vertical coordinates (x,y), and A is the area of ​​the region.

[0027] According to the present invention, a system for measuring the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of a rocket rupture diaphragm is provided, comprising:

[0028] Module M1: Based on laser confocal microscopy, the ruptured diaphragm pressure-sensitive structure placed horizontally on the measuring workbench is measured to obtain three-dimensional measurement point cloud data;

[0029] Module M2: Perform 2D discrete wavelet multi-layer decomposition on the acquired 3D measurement point cloud data;

[0030] Module M3: Use the decomposed data to reconstruct the pressure-sensitive structure point cloud features to obtain low-frequency point cloud data and high-frequency point cloud data;

[0031] Module M4: Use surface fitting to obtain the height of the lowest point of the surface for the low-frequency point cloud data, calculate the height difference between the height of the lowest point of the surface and the plane of the top diaphragm of the pressure-sensitive structure, and obtain the depth dimension of the pressure-sensitive structure;

[0032] Module M5: Calculate the surface roughness based on high-frequency point cloud data to obtain the morphological characteristics of the pressure-sensitive structure.

[0033] Preferably, the module M2 comprises:

[0034]

[0035] Among them, j represents the scale parameter, k = (k1, k2) represents the translation parameter, l represents the direction parameter, ψ j,k,l (m,n) is a discrete two-dimensional wavelet function, which is obtained by transforming the one-dimensional wavelet function ψ(m) by scale j and direction l; W f (j,k,l) ​​represents the information obtained after two-dimensional wavelet transform.

[0036] Preferably, the module M3 comprises:

[0037] f(x,y)≈d1+...+d N +f N

[0038] Among them, d1...d N is the high frequency part, f N It is the low frequency part.

[0039] Preferably, the module M4 comprises:

[0040]

[0041] Among them, a, b, c, P, Q are the parameters to be fitted;

[0042] The lowest point height of the pressure-sensitive structure is calculated based on the fitting parabola. The calculation formula is as follows

[0043]

[0044] The height of the top diaphragm plane of the pressure-sensitive structure is taken as the reference value, then z min The absolute value of is the depth of the pressure-sensitive structure.

[0045] Preferably, the module M5 comprises:

[0046]

[0047] Among them, Δx represents the micro-element width in the x direction, Δy represents the micro-element width in the y direction, z(x,y) represents the z coordinate of the point cloud with horizontal and vertical coordinates (x,y), and A is the area of ​​the region.

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

[0049] 1. The present invention can obtain the size and morphology data of the pressure-sensitive structure at one time through high-precision microscopic measurement, and combines multi-layer discrete two-dimensional wavelet decomposition and reconstruction technology to achieve the decoupling of the macroscopic size feature data and microscopic morphology feature data of the pressure-sensitive structure, so that the two do not affect each other. By using three-dimensional surface fitting, two-dimensional discrete integration and other technologies, key parameters such as depth and surface roughness are obtained respectively, and finally the depth size and bottom morphology characteristics of the arc-shaped bottom pressure-sensitive structure of the rocket rupture diaphragm are accurately measured, which provides a solid basic data for accurately estimating the performance of the diaphragm in engineering applications;

[0050] 2. The present invention has been tested in practice and found that the traditional contact and non-contact measurement methods cannot achieve the effect of the present invention when measuring the pressure-sensitive structure of the diaphragm. The existing roughness measurement and other morphological feature measurement methods are not ideal in terms of roughness measurement accuracy when encountering non-planar structures such as curved bottoms, and cannot achieve the effect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0052] Figure 1 The flowchart is a method for determining the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of a rocket rupture diaphragm. DETAILED DESCRIPTION

[0053] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0054] Example 1

[0055] like Figure 1As shown, according to the present invention, an effective method and system for measuring the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of a ruptured diaphragm includes: using confocal microscopy to obtain three-dimensional point cloud data of the pressure-sensitive structure of the diaphragm, using two-dimensional wavelet transform to perform multi-layer decomposition on the point cloud data, performing wavelet reconstruction on the decomposition result, obtaining the high-frequency point cloud part and the low-frequency point cloud part of the pressure-sensitive structure, fitting the low-frequency point cloud data with a rotating parabola, and calculating the depth of the pressure-sensitive structure based on the fitting parabola. The high-frequency point cloud data is used to calculate the surface morphological characteristic data of the pressure-sensitive structure, such as surface roughness, etc.

[0056] Specifically, the effective method for determining the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of the ruptured diaphragm includes:

[0057] Step 1: Use laser confocal microscopy to measure the diaphragm pressure-sensitive structure to obtain three-dimensional point cloud data of the pressure-sensitive structure.

[0058] Step 2: Perform two-dimensional discrete wavelet multi-layer decomposition on the obtained three-dimensional measurement point cloud data; in this embodiment, the number of layers of the two-dimensional discrete wavelet multi-layer decomposition is 6-9 layers; the adopted wavelet mother function is Sym5 or Sym8 wavelet;

[0059] Specifically, the measured point cloud data of the pressure-sensitive structure is decomposed into multiple layers based on discrete two-dimensional wavelet transform, and the transformation equation is as follows:

[0060] Discrete 2D Wavelet Transform

[0061]

[0062] Where j is the scale parameter, k = (k1, k2) is the translation parameter, and l is the direction parameter. j,k,l (m,n) is a discrete two-dimensional wavelet function, which is obtained by transforming the one-dimensional wavelet function ψ(m) by scale j and direction l.

[0063] Step 3: Use the decomposed data to reconstruct the pressure-sensitive structure point cloud features to obtain low-frequency point cloud data and high-frequency point cloud data;

[0064] Specifically, the decomposed result is reconstructed by wavelet, and the reconstruction equation is as follows

[0065] f(x,y)≈d1+...+d N +f N

[0066] where d n is the high frequency part, f n It is the low frequency part.

[0067] Step 4: Use surface fitting to obtain the height of the lowest point of the surface for the low-frequency point cloud data, calculate the height difference between the height of the lowest point of the surface and the plane of the diaphragm on the top of the pressure-sensitive structure, and obtain the depth dimension of the pressure-sensitive structure;

[0068] Specifically, the reconstructed low-frequency point cloud data of the pressure-sensitive structure is fitted by a rotating parabola, and the surface equation is as follows, where a, b, c, P, and Q are parameters to be fitted.

[0069]

[0070] In some cases, when it is impossible to fit the above five parameters at the same time, the parameters P and Q can be quickly fitted through the point cloud x, y coordinate data, and then the parameters a, b, c can be fitted according to the point cloud x, y, z coordinate data.

[0071] The lowest point height of the pressure-sensitive structure is calculated based on the fitting parabola. The calculation formula is as follows

[0072]

[0073] The height of the top diaphragm plane of the pressure-sensitive structure is taken as the reference value, then z min The absolute value of is the depth of the pressure-sensitive structure.

[0074] Step 5: Calculate the surface roughness based on the high-frequency point cloud data to obtain the morphological characteristics of the pressure-sensitive structure.

[0075] Specifically, the surface roughness is calculated for the reconstructed high-frequency point cloud data of the pressure-sensitive structure. The calculation method is as follows:

[0076]

[0077] Where A is the area of ​​the region.

[0078] The present invention also provides a system for effectively measuring the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of a ruptured diaphragm. The system for effectively measuring the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of a ruptured diaphragm can be realized by executing the process steps of the method for effectively measuring the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of the ruptured diaphragm, that is, those skilled in the art can understand the method for effectively measuring the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of the ruptured diaphragm as a preferred implementation mode of the system for effectively measuring the size and morphological characteristics of the arc-shaped bottom pressure-sensitive structure of the ruptured diaphragm.

[0079] Those skilled in the art know that, in addition to implementing the system, device and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0080] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for measuring the size and morphology of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm, characterized in that: include Step S1: measuring the pressure-sensitive structure of the ruptured diaphragm placed horizontally on a measuring workbench using a laser confocal microscope to obtain three-dimensional measurement point cloud data; Step S2: performing two-dimensional discrete wavelet multi-layer decomposition on the obtained three-dimensional measurement point cloud data; Step S3: reconstructing the pressure-sensitive structure point cloud features using the decomposed data to obtain low-frequency point cloud data and high-frequency point cloud data; Step S4: Using surface fitting to obtain the lowest point height of the surface for the low-frequency point cloud data, and calculating the height difference between the lowest point height of the surface and the plane of the top diaphragm of the pressure-sensitive structure to obtain the depth dimension of the pressure-sensitive structure; Step S5: Calculate the surface roughness based on the high-frequency point cloud data to obtain the pressure-sensitive structure morphology characteristics.

2. The method for measuring the size and topographic characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm according to claim 1 is characterized in that: The step S2 comprises: Among them, j represents the scale parameter, k = (k1, k2) represents the translation parameter, l represents the direction parameter, ψ j,k,l (m,n) is a discrete two-dimensional wavelet function, which is obtained by transforming the one-dimensional wavelet function ψ(m) through the scale j and direction l; W f (j,k,l) ​​represents the information obtained after two-dimensional wavelet transform.

3. The method for measuring the size and morphology characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm according to claim 1 is characterized in that: The step S3 comprises: f(x,y)≈d1+...+d N +f N Among them, d1...d N is the high frequency part, f N It is the low frequency part.

4. The method for measuring the size and topographic characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm according to claim 1 is characterized in that: The step S4 comprises: Among them, a, b, c, P, and Q are parameters to be fitted; The lowest point height of the pressure-sensitive structure is calculated based on the fitting parabola. The calculation formula is as follows The height of the top diaphragm plane of the pressure-sensitive structure is taken as the reference value, then z min The absolute value of is the depth of the pressure-sensitive structure.

5. The method for measuring the size and topographical characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm according to claim 1 is characterized in that: The step S5 comprises: Among them, Δx represents the width of the infinitesimal element in the x direction, Δy represents the width of the infinitesimal element in the y direction, z(x,y) represents the z coordinate of the point cloud with horizontal and vertical coordinates (x,y), and A is the area of ​​the region.

6. A system for measuring the size and topographical characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm, characterized in that: include Module M1: Measure the pressure-sensitive structure of a ruptured diaphragm placed horizontally on a measuring table using laser confocal microscopy to obtain 3D point cloud data. Module M2: Perform two-dimensional discrete wavelet multi-layer decomposition on the obtained three-dimensional measurement point cloud data; Module M3: Use the decomposed data to reconstruct the pressure-sensitive structure point cloud features to obtain low-frequency point cloud data and high-frequency point cloud data; Module M4: Use surface fitting to obtain the lowest point height of the surface for the low-frequency point cloud data, calculate the height difference between the lowest point height of the surface and the plane of the diaphragm on the top of the pressure-sensitive structure, and obtain the depth dimension of the pressure-sensitive structure; Module M5: Calculate surface roughness based on high-frequency point cloud data to obtain the morphological characteristics of the pressure-sensitive structure.

7. The system for measuring the size and topographic characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm according to claim 6 is characterized in that: The module M2 includes: Among them, j represents the scale parameter, k = (k1, k2) represents the translation parameter, l represents the direction parameter, ψ j,k,l (m,n) is a discrete two-dimensional wavelet function, which is obtained by transforming the one-dimensional wavelet function ψ(m) through the scale j and direction l; W f (j,k,l) ​​represents the information obtained after two-dimensional wavelet transform.

8. The system for measuring the size and topographical characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm according to claim 6 is characterized in that: The module M3 includes: f(x,y)≈d1+...+d N +f N Among them, d1...d N is the high frequency part, f N It is the low frequency part.

9. The system for measuring the size and topographic characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm according to claim 6 is characterized in that: The module M4 includes: Among them, a, b, c, P, and Q are parameters to be fitted; The lowest point height of the pressure-sensitive structure is calculated based on the fitting parabola. The calculation formula is as follows The height of the top diaphragm plane of the pressure-sensitive structure is taken as the reference value, then z min The absolute value of is the depth of the pressure-sensitive structure.

10. The system for measuring the size and topographic characteristics of the curved bottom pressure-sensitive structure of a rocket rupture diaphragm according to claim 6, characterized in that: The module M5 includes: Among them, Δx represents the width of the infinitesimal element in the x direction, Δy represents the width of the infinitesimal element in the y direction, z(x,y) represents the z coordinate of the point cloud with horizontal and vertical coordinates (x,y), and A is the area of ​​the region.

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