Synchronous ultrasonic measurement method and system for thickness of coating and lubricating film

Abstract

The invention discloses a synchronous ultrasonic measurement method and system for the thickness of a coating and a lubricating film. The method comprises the following steps: constructing a pseudo reflection coefficient according to an overall reflection signal obtained by a four-layer structure and a reference signal obtained by an air interface; a pseudo reflection coefficient amplitude spectrum is obtained, when a minimum value point exists in the pseudo reflection coefficient amplitude spectrum, pseudo reflection coefficient information corresponding to the minimum value point is extracted to solve the coating thickness # imgabs0 #, and the lubricating film thickness # imgabs1 # is obtained through the frequency at the minimum value point; if the minimum value point does not exist, pseudo reflection coefficient information is extracted according to the ultrasonic frequency corresponding to the position with the maximum amplitude in the reference signal amplitude spectrum, and the lubricating film thickness # imgabs2 is solved; the # imgabs 3 # and the # imgabs 4 # are combined to measure the large-range lubricating film thickness # imgabs 5 # of the four-layer structure; and the synchronous measurement of the thicknesses of the coating and the lubricating film of the friction pair with the four-layer structure is realized in combination with # imgabs6 and # imgabs7. According to the method, incident signals do not need to be separated, transmission errors in the calculation process are reduced, the reliability and the measurement precision are higher, and the coating thickness and the lubricating film thickness can be measured at the same time.

Description

Background Art

[0002] In various engineering scenarios, it is not uncommon to use lubricating liquid and coatings between relatively moving parts to provide equipment with better lubrication performance and longer service life. In sliding bearings, in addition to using lubricating liquid to reduce friction and wear, a coating is also applied to the bearing surface to improve the self-lubricating performance and high temperature resistance of the bearing; in key components such as pistons and cylinders of aircraft engines, a combination of lubricating liquid and coating is often used. The lubricating liquid is responsible for providing continuous lubrication during high-speed operation, while the coating can provide additional protection under extreme temperature and pressure conditions to prevent direct contact and wear between components; in automobile transmission systems, components such as gearboxes and transmission shafts will generate a lot of friction and heat during operation. In order to reduce the friction coefficient and reduce wear, a wear-resistant and high-temperature resistant coating is usually applied to the surface of gears and shafts while using lubricating liquid for lubrication to improve the overall performance and reliability of the transmission system. When various mechanical equipment works under extreme conditions such as high temperature and high pressure, it is very easy for the lubricating film to rupture and enter a mixed lubrication state, resulting in abnormal wear of components. Therefore, measuring the lubricating film thickness of the four-layer friction pair is crucial for monitoring the lubrication state of mechanical equipment and then carrying out predictive maintenance.

[0003] Focusing on the measurement of lubricating film thickness, the ultrasonic method has become the most promising dynamic measurement method for lubricating film thickness due to its advantages of non-destructive testing and small sensor structure size, and has begun to gain research attention in structures such as pistons and sliding bearings.

[0004] At present, focusing on the typical three-layer friction pair structure (solid-lubricating film-solid), the ultrasonic method has broken through the bottlenecks of continuous measurement and high-resolution measurement of lubricating film thickness over a large range; however, for the lubricating film thickness measurement of the four-layer structure (solid-coating-lubricating film-solid) containing a thin coating, it is still a bottleneck that is difficult to break through.

[0005] First, for the four-layer structure friction pair, the time interval of the reflected echoes at the upper and lower interfaces of the thin coating is short, and waveform superposition often occurs. Therefore, the echoes cannot be separated, and the method of calculating the lubricating film thickness using the three-layer structure model based on the classical reflection coefficient (RC) will fail. Secondly, the method of using reference echo and Gaussian wave to approximate the solid-coating interface reflection echo in the overlapping echo signal and then calculate the lubricating film thickness has a limited measurement range and is only applicable to the lubricating film thickness measurement below 10μm. It also ignores the influence of multiple reflection echoes in the coating, and there are large estimation errors. Finally, based on the four-layer structure model of the classical reflection coefficient (RC), the lubricating film thickness measurement below 100 μm can be achieved. However, this method requires obtaining the coating thickness in advance and separating the incident signal. However, in engineering practice, the coating thickness is difficult to obtain accurately, and the separation of the incident signal is highly dependent on the accuracy of the coating thickness. A slight coating thickness measurement error will cause a measurement error in the lubricating film thickness that is difficult to ignore, resulting in poor stability of this method.

[0006] Therefore, how to achieve accurate measurement of the coating thickness of the four-layer friction pair and the lubricating film thickness over a large range is a current research difficulty. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a synchronous ultrasonic measurement method and system for coating and lubricating film thickness in view of the deficiencies in the above-mentioned prior art, which is used to solve the technical problems that the coating thickness is difficult to measure in engineering practice, the lubricating film thickness measurement method in the existing four-layer structure has poor stability, weak anti-interference ability and small measurement range, and realize the synchronous measurement of the coating thickness and a large range of lubricating film thickness of the four-layer structure friction pair.

[0008] The present invention adopts the following technical solutions: A method for synchronous ultrasonic measurement of coating and lubricating film thickness comprises the following steps: Construct pseudo reflection coefficients; Obtain the pseudo-reflection coefficient amplitude spectrum. If there is a minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information corresponding to the frequency at the minimum point to solve the coating thickness. , and the lubricating film thickness is obtained by the frequency at the minimum point If there is no minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information according to the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness. ; Based on the lubricant film thickness obtained as well as Achieve a wide range of lubricating film thickness with four-layer structure Measurement of coating thickness Realize the simultaneous measurement of coating and lubricating film thickness of four-layer friction pairs.

[0009] Preferably, constructing the pseudo reflection coefficient is specifically as follows: Before the test begins, the lubricating medium in the four-layer structure is removed, ultrasonic waves are emitted to the solid-coating-air structure, and the ultrasonic reflection echo of the air interface is collected and stored as a reference signal. ; After the test begins, ultrasonic waves are continuously emitted to the four-layer structure, and the ultrasonic reflection echoes of the lubricating film interface are collected and stored as the overall reflection signal. ; The reference signal acquired and the overall reflected signal Perform FFT operation to obtain the amplitude spectrum and phase spectrum of the reference signal and the overall reflection signal, and use the reference signal and the overall reflection signal to construct the pseudo reflection coefficient , the pseudo reflection coefficient amplitude spectrum is obtained as And the pseudo-reflection coefficient phase spectrum is .

[0010] Preferably, the pseudo reflection coefficient Specifically: .

[0012] Preferably, the lubricating film thickness Specifically:

[0013] in, is the speed of sound in the lubricating film; is the first-order resonance frequency in the pseudo-reflection coefficient amplitude spectrum.

[0014] Preferably, the coating thickness Specifically:

[0015] in, The frequency of the minimum point The corresponding pseudo reflection coefficient at ; For medium The acoustic impedance, , For medium The density of For medium The speed of sound in is the acoustic impedance of air; To convert the symbol, .

[0016] Preferably, the lubricating film thickness Specifically:

[0017] in, is the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum; For medium The acoustic impedance, , For medium The density of For medium The speed of sound in It is the first in the solid-coating-lubricating film-solid structure. The equivalent impedance of the dielectric layer.

[0018] Preferably, for:

[0019] in, is the equivalent impedance of the coating in the solid-coating-lubricating film-solid structure; is the acoustic impedance of the coating, is the density of the coating, is the speed of sound in the coating; is the wave number of the coating; is the coating thickness.

[0020] Preferably, the equivalent impedance of the coating in the solid-coating-lubricating film-solid structure is for:

[0021] in, is the acoustic impedance of medium 1, is the density of medium 1, is the speed of sound in medium 1; is the equivalent impedance of the coating in the solid-coating-air structure; For frequency The corresponding pseudo reflection coefficient is .

[0022] Preferably, for:

[0023] in, is the equivalent impedance of air in the solid-coating-air structure.

[0024] In a second aspect, an embodiment of the present invention provides a synchronous ultrasonic measurement system for coating and lubricating film thickness, comprising: Coefficient module, constructs pseudo reflection coefficients; The judgment module obtains the pseudo reflection coefficient amplitude spectrum. If there is a minimum point in the pseudo reflection coefficient amplitude spectrum, the pseudo reflection coefficient information corresponding to the frequency at the minimum point is extracted to solve the coating thickness. , and the lubricating film thickness is obtained by the frequency at the minimum point If there is no minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information according to the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness. ; Measuring module based on the lubricant film thickness as well as Achieve a wide range of lubricating film thickness with four-layer structure Measurement of coating thickness Realize the simultaneous measurement of coating and lubricating film thickness of four-layer friction pairs.

[0025] In a third aspect, a computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned method for synchronous ultrasonic measurement of coating and lubricating film thickness when executing the computer program.

[0026] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, comprising a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for synchronous ultrasonic measurement of coating and lubricating film thickness.

[0027] Compared with the prior art, the present invention has at least the following beneficial effects: A synchronous ultrasonic measurement method for coating and lubricating film thickness, which constructs a pseudo reflection coefficient (PRC) based on the ratio of the overall reflection signal obtained under a four-layer structure and the reference signal obtained at the air interface; obtains the pseudo reflection coefficient amplitude spectrum, and monitors whether there is a minimum point in the pseudo reflection coefficient amplitude spectrum; if there is a minimum point, the pseudo reflection coefficient information corresponding to the frequency at the minimum point is extracted to solve the coating thickness , and the oil film thickness is obtained by the frequency at the minimum point ; If there is no minimum point, extract the pseudo-reflection coefficient information of the ultrasonic frequency at the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness ; Combine as well as Achieve a wide range of lubricating film thickness for four-layer friction pairs Measurement of coating thickness Realize the simultaneous measurement of coating and lubricating film thickness of four-layer friction pairs.

[0028] Furthermore, constructing a pseudo-reflection coefficient using the overall reflection signal of the four-layer structure and the reference signal of the air interface can effectively circumvent the process of solving the incident signal in the classical reflection coefficient (RC) model, fundamentally reducing the error transmission in the calculation process and having better measurement accuracy and anti-interference ability.

[0029] Furthermore, when the lubricating film thickness is large, a minimum point will appear in the pseudo-reflection coefficient amplitude spectrum, and the lubricating film thickness can be obtained by the frequency at the minimum point. , providing a basis for the large-scale measurement of the thickness of the four-layer structure lubricating film. At the same time, the pseudo-reflection coefficient information corresponding to the minimum point can be used to measure the coating thickness. The solution provides a basis for the synchronous ultrasonic measurement of coating thickness and lubricating film thickness.

[0030] Furthermore, when the lubricating film thickness is small, the pseudo reflection coefficient information of the frequency with the maximum amplitude in the reference signal amplitude spectrum is extracted to obtain the lubricating film thickness. , which increases the measurement range of the four-layer structure lubricating film thickness and provides a basis for the synchronous measurement of coating thickness and lubricating film thickness.

[0031] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0032] In summary, the present invention uses the overall reflection signal and the reference signal collected by the sensor to construct a pseudo reflection coefficient (PRC) without separating the incident signal, decouples the lubricating film thickness and the coating thickness from the pseudo reflection coefficient, and accurately obtains the coating thickness, thereby improving the accuracy and stability of the lubricating film thickness measurement of the four-layer structure, and has important engineering significance for the synchronous and accurate measurement of the coating and lubricating film thickness of the four-layer friction pair.

[0033] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings to be used in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 Signal processing flow chart for synchronous calculation of coating and lubricating film thickness of four-layer friction pair; FIG2 is a schematic diagram of the propagation of ultrasonic waves in a four-layer friction pair, wherein FIG2 (a) is a schematic diagram of the propagation of ultrasonic waves in a solid-coating-air structure, and FIG2 (b) is a schematic diagram of the propagation of ultrasonic waves in a solid-coating-lubricating film-solid structure; Figure 3 is the pseudo reflection coefficient amplitude Follow The change relationship diagram of Figure 4 This is a schematic diagram of the measurement point distribution of the thin-coated sliding bearing in the aviation fuel gear pump; Figure 5 The pseudo-reflection coefficient amplitude spectrum of three measuring points at room temperature, rotation speed of 1000rpm, and oil discharge pressure of 1.5MPa; Figure 6 It is the coating thickness measurement result based on ultrasonic pseudo-reflection coefficient method; Figure 7 is the coating thickness measurement result by optical microscopy; FIG8 is a comparison diagram of the measurement results and the theoretical solution at different speeds and different oil discharge pressures at room temperature, wherein FIG8 (a) is a comparison diagram of the measurement results and the theoretical solution at different speeds, and FIG8 (b) is a comparison diagram of the measurement results and the theoretical solution at different oil discharge pressures; Fig. 9 A schematic diagram of a computer device provided by an embodiment of the present invention; Fig.10 The present invention is a block diagram of an electronic device provided according to an embodiment. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0038] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0039] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0040] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0041] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0042] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0043] The present invention provides a method for synchronous ultrasonic measurement of coating and lubricating film thickness, which constructs a pseudo reflection coefficient (PRC) according to the overall reflection signal obtained in the four-layer structure and the reference signal obtained at the air interface; obtains the pseudo reflection coefficient amplitude spectrum, and monitors whether there is a minimum point in the pseudo reflection coefficient amplitude spectrum; if there is a minimum point, extracts the pseudo reflection coefficient information corresponding to the minimum point to solve the coating thickness. , and the lubricating film thickness is obtained by the frequency at the minimum point ; If there is no minimum point, the pseudo-reflection coefficient information is extracted according to the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness ; Combine as well as Achieve a wide range of lubricating film thickness with four-layer structure measurement; and then combined with and The invention realizes the simultaneous measurement of the coating and lubricating film thickness of the four-layer friction pair. Compared with the traditional reflection coefficient (RC) method, the invention does not need to separate the incident signal, reduces the transmission error in the calculation process, has higher reliability and measurement accuracy, and can simultaneously measure the coating thickness and lubricating film thickness.

[0044] See also Figure 1 The present invention provides a method for synchronous ultrasonic measurement of coating and lubricating film thickness, comprising the following steps: S1, pseudo reflection coefficient construction; Please refer to Figure 2 for a schematic diagram of ultrasonic wave propagation in a four-layer friction pair. In the frequency domain, the incident signal is expressed as Indicates; the collected ultrasonic echo signal of the solid-coating-air structure is used as the reference signal The ultrasonic echo signal of the solid-coating-lubricating film-solid structure is expressed as the overall reflection signal Representation; The amplitude spectrum and phase spectrum of the reference signal and the overall reflection signal are obtained through FFT operation, and the pseudo reflection coefficient is constructed using the reference signal and the overall reflection signal , the pseudo-reflection coefficient amplitude spectrum is , the pseudo reflection coefficient phase spectrum is .

[0045] Pseudo reflection coefficient Specifically:

[0046] S2, lubricating film thickness and coating thickness Measurement; See also Figure 3 , the amplitude of pseudo reflection coefficient Follow As the thickness of the lubricating film gradually increases, the amplitude of the pseudo-reflection coefficient shows a minimum point phenomenon. By identifying the minimum point in the pseudo-reflection coefficient amplitude spectrum, the lubricating film thickness is calculated using the frequency at the minimum point. Specifically:

[0047] in, is the speed of sound in the lubricating film; is the first-order resonance frequency in the pseudo-reflection coefficient amplitude spectrum.

[0048] Coating thickness Specifically:

[0049] in, The frequency of the minimum point The corresponding pseudo reflection coefficient at ; For medium The acoustic impedance, For medium The density of For medium The speed of sound in is the acoustic impedance of air, is the density of air, is the speed of sound in air, To convert the symbol, .

[0050] S3, lubricating film thickness Measurement; Pseudo-reflection coefficient amplitude spectrum When there is no minimum point in the reference signal amplitude spectrum, the pseudo reflection coefficient information of the ultrasonic frequency at the maximum amplitude is extracted, combined with the coating thickness Lubricant film thickness solved Specifically:

[0051]

[0052]

[0053] in, is the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum; For the frequency The corresponding pseudo reflection coefficient at ; For medium The acoustic impedance, , For medium The density of For medium The speed of sound in It is the first in the solid-coating-lubricating film-solid structure. Equivalent impedance of the layer medium; is the acoustic impedance of medium 1 in the solid-coating-lubricating film-solid structure, is the density of medium 1, is the speed of sound in medium 1; is the equivalent impedance of the coating in the solid-coating-air structure; is the acoustic impedance of the coating, is the density of the coating, is the speed of sound in the coating; is the wave number of the coating; It is the first in the solid-coating-lubricating film-solid structure. Equivalent impedance of the layer medium; is the equivalent impedance of the coating in the solid-coating-air structure, expressed as:

[0054] in, is the equivalent impedance of air in the solid-coating-air structure, expressed as:

[0055] S4. Synchronous measurement of coating and lubricating film thickness of four-layer friction pair.

[0056] Combine the lubricating film thickness measured in step S2 and step S3 and A wide range of lubricating film thickness can be achieved for the four-layer friction pair The measurement of and the coating thickness measured in step S2 That is to achieve the simultaneous measurement of the coating and lubricating film thickness of the four-layer friction pair.

[0057] It will be appreciated by those skilled in the art that various aspects of the present invention may be implemented as systems, methods or program products. Therefore, various aspects of the present invention may be specifically implemented in the following forms, namely: complete hardware implementation, complete software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, which may be collectively referred to herein as "circuits", "modules" or "platforms".

[0058] In another embodiment of the present invention, a synchronous ultrasonic measurement system for coating and lubricating film thickness is provided. The system can be used to implement the above-mentioned synchronous ultrasonic measurement method for coating and lubricating film thickness. Specifically, the synchronous ultrasonic measurement system for coating and lubricating film thickness includes a coefficient module, a judgment module and a measurement module.

[0059] Among them, the coefficient module constructs the pseudo reflection coefficient; The judgment module obtains the pseudo reflection coefficient amplitude spectrum. If there is a minimum point in the pseudo reflection coefficient amplitude spectrum, the pseudo reflection coefficient information corresponding to the frequency at the minimum point is extracted to solve the coating thickness. , and the lubricating film thickness is obtained by the frequency at the minimum point If there is no minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information according to the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness. ; Measuring module based on the lubricant film thickness as well as Achieve a wide range of lubricating film thickness with four-layer structure Measurement of coating thickness Realize the simultaneous measurement of coating and lubricating film thickness of four-layer friction pairs.

[0060] In another embodiment of the present invention, a terminal device is provided, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the synchronous ultrasonic measurement method of the coating and lubricating film thickness, including: Construct the pseudo reflection coefficient; obtain the pseudo reflection coefficient amplitude spectrum. If there is a minimum point in the pseudo reflection coefficient amplitude spectrum, extract the pseudo reflection coefficient information corresponding to the frequency at the minimum point to solve the coating thickness. , and the lubricating film thickness is obtained by the frequency at the minimum point If there is no minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information according to the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness. ; Based on the obtained lubricating film thickness as well as Achieve a wide range of lubricating film thickness with four-layer structure Measurement of coating thickness Realize the simultaneous measurement of coating and lubricating film thickness of four-layer friction pairs.

[0061] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a terminal device for storing programs and data. It is understandable that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device, and can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that more specific examples (non-exhaustive list) of the computer-readable storage medium here include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0062] Computer readable storage media also include data signals propagated in baseband or as part of a carrier wave, which carry readable program codes. Such propagated data signals can take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable storage medium can also be any readable medium other than a readable storage medium, which can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program code contained on the readable storage medium can be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above.

[0063] Program code for performing the operations of the present invention may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., through the Internet using an Internet service provider).

[0064] The processor may load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the method for synchronous ultrasonic measurement of coating and lubricating film thickness in the above embodiment; the processor may load and execute the following steps: Construct the pseudo reflection coefficient; obtain the pseudo reflection coefficient amplitude spectrum. If there is a minimum point in the pseudo reflection coefficient amplitude spectrum, extract the pseudo reflection coefficient information corresponding to the frequency at the minimum point to solve the coating thickness. , and the lubricating film thickness is obtained by the frequency at the minimum point If there is no minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information according to the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness. ; Based on the obtained lubricating film thickness as well as Achieve a wide range of lubricating film thickness with four-layer structure Measurement of coating thickness Realize the simultaneous measurement of coating and lubricating film thickness of four-layer friction pairs.

[0065] See also Fig. 9 , the terminal device is a computer device, and the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the method for synchronous ultrasonic measurement of the thickness of the coating and lubricating film in the embodiment is implemented. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the system for synchronous ultrasonic measurement of the thickness of the coating and lubricating film in the embodiment are implemented. To avoid repetition, it is not described one by one here.

[0066] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Fig. 9 This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0067] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, central processing units, graphics processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, data processing logic based on quantum computing, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.

[0068] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0069] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0070] Any reference to a memory, database or other medium used in the embodiments provided in the present application may include at least one of a non-volatile and a volatile memory. Non-volatile memory may include a read-only memory (ROM), a magnetic tape, a floppy disk, a flash memory, an optical memory, a high-density embedded non-volatile memory, a resistive random access memory (ReRAM), a magnetic random access memory (MRAM), a ferroelectric random access memory (FRAM), a phase change memory (PCM), a graphene memory, etc. Volatile memory may include a random access memory (RAM) or an external cache memory, etc. As an illustration and not limitation, RAM may be in various forms, such as a static random access memory (SRAM) or a dynamic random access memory (DRAM), etc.

[0071] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0072] See also Fig.10 The terminal device is an electronic device 600, and the electronic device is in the form of a general-purpose computing device. The components of the electronic device may include, but are not limited to: at least one processing unit 610, at least one storage unit 620, a bus 630 connecting different platform components (including the storage unit 620 and the processing unit 610), a display unit 640, etc.

[0073] The storage unit stores program codes, which can be executed by the processing unit 610, so that the processing unit 610 performs the steps according to various exemplary embodiments of the present invention described in the above method section of this specification. For example, the processing unit 610 can perform the following steps: Figure 1 Follow the steps shown in .

[0074] The storage unit 620 may include a readable medium in the form of a volatile storage unit, such as a random access memory unit (RAM) 6201 and / or a cache memory unit 6202 , and may further include a read-only memory unit (ROM) 6203 .

[0075] The storage unit 620 may also include a program / utility 6204 having a set (at least one) of program modules 6205, such program modules 6205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0076] Bus 630 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0077] The electronic device 600 may also communicate with one or more external devices 700 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 600, and / or communicate with any device that enables the electronic device 600 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 650. Furthermore, the electronic device 600 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 660. The network adapter 660 may communicate with other modules of the electronic device 600 via a bus 630. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 600, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage platforms, etc.

[0078] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0079] Experimental verification example: Dynamic experiments were performed on an aviation fuel gear pump to verify the effectiveness of the method. Figure 4 , Schematic diagram of measuring point distribution of thin-coated sliding bearings in aviation fuel gear pumps. The selection of lubricating film thickness measuring points follows the principle of measuring the lubricating film thickness in the main load-bearing area to the greatest extent and obtaining the circumferential distribution of the lubricating film thickness of the bearing. A total of 3 lubricating film thickness measuring points are set on the active sliding bearing, and a first ultrasonic sensor 1, a second ultrasonic sensor 2 and a third ultrasonic sensor 3 are respectively set at each lubricating film thickness measuring point, wherein measuring point 1 is located in the main load-bearing area, and measuring points 2 and 3 are used to obtain the circumferential distribution of the lubricating film thickness.

[0080] The experimental system mainly consists of an aviation fuel gear pump, a hydraulic control system, a data acquisition system, and an ultrasonic lubricating film thickness measurement system. In the experiment, the speed of the aviation fuel gear pump is adjusted by a motor, the oil inlet and outlet pressures are controlled by a relief valve, and the oil inlet pressure is fixed at about 0.5MPa. The ultrasonic lubricating film thickness measurement system is the FMS-100 system produced by Tribosonics in the UK. The system integrates an ultrasonic pulse transmitter and receiver, a data acquisition card, and a computer. The system emits pulses at a repetition frequency of 20kHz to excite the ultrasonic sensor to generate ultrasonic waves, and collects ultrasonic reflection echoes at a sampling frequency of 100MHz and uploads them to the computer for processing.

[0081] See also Figure 1 , signal processing flow chart for simultaneous calculation of coating and lubricating film thickness of four-layer friction pair. According to the signal processing flow, the ultrasonic signal is processed to calculate the coating and lubricating film thickness. Figure 5 , at room temperature, the speed is 1000rpm, and the oil discharge pressure is 1.5MPa, the amplitude spectrum of the pseudo-reflection coefficient at the three measuring points. By observing the amplitude spectrum, it can be found that the minimum point only appears in the amplitude spectrum of measuring point 3. Therefore, the signal of measuring point 3 is extracted for analysis to calculate the coating thickness. Please refer to Figure 6 , based on the coating thickness measurement results of the ultrasonic pseudo-reflection coefficient method, a total of 5 working conditions were selected, 10 ultrasonic reflection signals were extracted for calculation under each working condition, and the results were averaged. In order to verify the accuracy of the coating thickness measurement results, the cross section of the bearing was obtained by mechanical processing, and the coating thickness at three positions on the cross section was observed and measured using an optical microscope. Please refer to Figure 7, the coating thickness measurement results of the optical microscope method. The average value of the coating thickness measurement results based on the ultrasonic pseudo-reflection coefficient method is taken as the result of the ultrasonic measurement, and the average value of the measurement results at three positions measured by the optical microscope is taken as the result of the optical measurement. The ultrasonic measurement results are compared with the optical measurement results. The relative error is only 13.4%, which verifies the effectiveness of the present invention. The lubricating film thickness takes the average value of 500 calculation results as the final measurement result. The lubricating film thickness measurement results at room temperature are compared with the theoretical solution. Please refer to Figure 8, which is a comparison result diagram of the measurement results and the theoretical solution at different speeds and different oil discharge pressures at room temperature. It can be seen that the measurement results and the theoretical results show good consistency at each measuring point, which shows the accuracy of the measurement results.

[0082] In summary, the present invention provides a method and system for synchronous ultrasonic measurement of coating and lubricating film thickness, which utilizes the overall reflection signal and reference signal collected by the sensor to construct a pseudo-reflection coefficient, without separating the incident signal, and decouples the lubricating film thickness and the coating thickness from the pseudo-reflection coefficient, thereby accurately obtaining the coating thickness, thereby improving the accuracy and stability of the lubricating film thickness measurement in the four-layer friction pair, and has important engineering significance for the synchronous and accurate measurement of the coating and lubricating film thickness of the four-layer friction pair.

[0083] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0084] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0085] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0086] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0087] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0088] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0089] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0090] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0091] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0092] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0093] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for synchronous ultrasonic measurement of coating and lubricating film thickness, characterized in that: The following steps are involved: Construct pseudo reflection coefficients; Obtain the pseudo-reflection coefficient amplitude spectrum. If there is a minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information corresponding to the frequency at the minimum point to solve the coating thickness. , and the lubricating film thickness is obtained by the frequency at the minimum point If there is no minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information according to the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness. ; Based on the lubricating film thickness as well as Achieve a wide range of lubricating film thickness with four-layer structure Measurement of coating thickness Realize the simultaneous measurement of coating and lubricating film thickness of four-layer friction pairs.

2. The method for synchronous ultrasonic measurement of coating and lubricating film thickness according to claim 1, characterized in that: The pseudo reflection coefficient is constructed as follows: Before the test begins, the lubricating medium in the four-layer structure is removed, ultrasonic waves are emitted to the solid-coating-air structure, and the ultrasonic reflection echo of the air interface is collected and stored as a reference signal. ; After the test begins, ultrasonic waves are continuously emitted to the four-layer structure, and the ultrasonic reflection echoes of the lubricating film interface are collected and stored as the overall reflection signal. ; The reference signal acquired and the overall reflected signal Perform FFT operation to obtain the amplitude spectrum and phase spectrum of the reference signal and the overall reflection signal, and use the reference signal and the overall reflection signal to construct the pseudo reflection coefficient , the pseudo reflection coefficient amplitude spectrum is obtained as And the pseudo-reflection coefficient phase spectrum is .

3. The method for synchronous ultrasonic measurement of coating and lubricating film thickness according to claim 2, characterized in that: Pseudo reflection coefficient Specifically:

4. The method for synchronous ultrasonic measurement of coating and lubricating film thickness according to claim 1, characterized in that: Lubricating film thickness Specifically: in, is the speed of sound in the lubricating film; is the first-order resonance frequency in the pseudo-reflection coefficient amplitude spectrum.

5. The method for synchronous ultrasonic measurement of coating and lubricating film thickness according to claim 4, characterized in that: Coating thickness Specifically: in, The frequency of the minimum point The corresponding pseudo reflection coefficient at ; For medium The acoustic impedance, , For medium The density of For medium The speed of sound in is the acoustic impedance of air; To convert the symbol, .

6. The method for synchronous ultrasonic measurement of coating and lubricating film thickness according to claim 1, characterized in that: Lubricating film thickness Specifically: in, is the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum; For medium The acoustic impedance, , For medium The density of For medium The speed of sound in It is the first in the solid-coating-lubricating film-solid structure. The equivalent impedance of the dielectric layer.

7. The method for synchronous ultrasonic measurement of coating and lubricating film thickness according to claim 6, characterized in that: for: in, is the equivalent impedance of the coating in the solid-coating-lubricating film-solid structure; is the acoustic impedance of the coating, is the density of the coating, is the speed of sound in the coating; is the wave number of the coating; is the coating thickness.

8. The method for synchronous ultrasonic measurement of coating and lubricating film thickness according to claim 7, characterized in that: Equivalent impedance of coating in solid-coating-lubricating film-solid structure for: in, is the acoustic impedance of medium 1, is the density of medium 1, is the speed of sound in medium 1; is the equivalent impedance of the coating in the solid-coating-air structure; For frequency The corresponding pseudo reflection coefficient is .

9. The method for synchronous ultrasonic measurement of coating and lubricating film thickness according to claim 8, characterized in that: for: in, is the equivalent impedance of air in the solid-coating-air structure.

10. A synchronous ultrasonic measurement system for coating and lubricating film thickness, characterized in that: include: Coefficient module, constructs pseudo reflection coefficients; The judgment module obtains the pseudo reflection coefficient amplitude spectrum. If there is a minimum point in the pseudo reflection coefficient amplitude spectrum, the pseudo reflection coefficient information corresponding to the frequency at the minimum point is extracted to solve the coating thickness. , and the lubricating film thickness is obtained by the frequency at the minimum point If there is no minimum point in the pseudo-reflection coefficient amplitude spectrum, extract the pseudo-reflection coefficient information according to the ultrasonic frequency corresponding to the maximum amplitude in the reference signal amplitude spectrum to solve the lubricating film thickness. ; Measuring module based on the lubricant film thickness as well as Achieve a wide range of lubricating film thickness with four-layer structure Measurement of coating thickness Realize the simultaneous measurement of coating and lubricating film thickness of four-layer friction pairs.

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