Method and system for reconstructing three-dimensional blade tip clearance signal of an aero-engine by undersampling fractal dimension

Abstract

The application discloses a kind of aero-engine three-dimensional blade tip clearance signal undersampling fractal reconstruction method and system, belong to blade non-contact test field, for three-dimensional blade tip clearance undersampling signal, the sampling model of measurement signal is established;By constructing Fourier sparse matrix, the sparse representation in frequency domain is carried out to original signal, and the observation matrix is deduced, and three-dimensional blade tip clearance signal compressed sensing model is established;The number of three-dimensional blade tip clearance sensors is selected by correlation coefficient minimization theory, and sensor installation position is optimized;The application provides theoretical guidance for the quantitative diagnosis of aero-engine blade crack based on three-dimensional blade tip clearance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of blade non-contact testing, and particularly relates to a three-dimensional blade tip gap signal undersampling fractal dimension reconstruction method and system for an aero-engine. BACKGROUND

[0002] The aero-engine is called the "heart" of the airplane, and the turbine blade as a key part of the aero-engine directly affects the safety and stability of the engine. The rotating blade is prone to fatigue cracks and even breakage due to huge working load during operation, which seriously endangers the safety of the engine operation.

[0003] At present, in the research on monitoring the blade vibration by using the non-contact measurement method, the circumferential vibration of the blade is usually only concerned in the measurement process, and the reflection of the blade crack characteristics is not comprehensive. In the actual operation process of the aero-engine, the blade fault will cause the deformation of the blade in the three-dimensional space, and the three-dimensional characteristics are presented. However, in the actual measurement of the three-dimensional blade tip gap, due to the limitation of the number and installation position of the sensors on the casing, the sampling of the three-dimensional blade tip gap signal does not meet the Shannon sampling theorem, resulting in a serious undersampling signal, causing spectrum aliasing and distortion. The Fourier transform and other spectrum analysis methods cannot be used for analysis, so that the blade fault information cannot be diagnosed, and therefore it is necessary to reconstruct the undersampling signal of the three-dimensional blade tip gap and restore the spectrum characteristics.

[0004] A large number of researches on the processing of undersampling signals have been carried out at home and abroad, and some reconstruction methods have been proposed. Most of the reconstruction methods depend on the prior information of the blade vibration, and cannot reconstruct the multi-frequency characteristics of the signal. In recent years, the compressive sensing developed on the basis of the sparse representation theory provides a new idea for solving the above problems. The compressive sensing theory represents the signal through the sparse characteristics of the signal, samples the signal at a rate much lower than the Shannon sampling frequency, and restores the complete original signal at the back end by using the signal reconstruction algorithm, thereby reducing the hardware cost. By using the compressive sensing characteristics, the spectrum aliasing phenomenon caused by the three-dimensional blade tip gap undersampling signal can be well eliminated under the condition of non-uniform sampling. However, the reconstruction of the three-dimensional blade tip gap undersampling signal is still blank, and therefore it is necessary to use the compressive sensing method to reconstruct the fractal dimension of the three-dimensional blade tip gap signal, so as to comprehensively extract the fault information of the blade crack. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a three-dimensional blade tip gap signal undersampling fractal dimension reconstruction method and system for an aero-engine, which solves the technical problem of signal spectrum aliasing and distortion caused by the undersampling characteristics in the sampling process of the three-dimensional blade tip gap signal.

[0006] The application adopts the following technical solutions:

[0007] The three-dimensional blade tip clearance signal undersampling fractal reconstruction method of an aero-engine comprises the following steps:

[0008] S1, for the three-dimensional blade tip clearance undersampling signal, the theoretical arrival time of the blade passing through the sensor is calculated, and a sampling model of the measurement signal is established;

[0009] S2, the three-dimensional blade tip clearance original signal is expressed in the form of a plurality of harmonic superpositions by constructing a Fourier sparse matrix, a sparse representation in the frequency domain is performed, and an observation matrix is derived according to the sampling model obtained in step S1 to establish a three-dimensional blade tip clearance signal compressed sensing model;

[0010] S3, the number of three-dimensional blade tip clearance sensors is selected by the correlation coefficient minimization theory, and the installation position of the sensor is optimized to obtain an optimal sampling model of the three-dimensional blade tip clearance signal, an optimal observation matrix is constructed according to the obtained optimal sampling model, and is input into the compressed sensing model obtained in step S2 to solve the three-dimensional blade tip clearance original signal.

[0011] Preferably, in step S1, the sampling model of the measurement signal is specifically:

[0012] According to the sampling process of the three-dimensional blade tip clearance of the aero-engine, the undersampling characteristics of the three-dimensional blade tip clearance measurement signal are derived; a sampling model of the three-dimensional blade tip clearance signal is established through the sampling sequence of the three-dimensional blade tip clearance virtual sensor, the actually installed sensor and the sensor installation position, and then the theoretical arrival time of the blade passing through a certain sensor is derived; and a mathematical model of the sampling of the three-dimensional blade tip clearance observation signal vector from the original signal vector is obtained.

[0013] Preferably, from J the installable three-dimensional blade tip clearance sensor positions, the K position is selected to install the sensor, the number of sensors is K , and the sampling sequence of the sensor installation position is , a k is the installation position of the k sensor, which satisfies: , the sampling model of the three-dimensional blade tip clearance signal is represented as: J , K , A ).

[0014] Preferably, the sampling process of the signal is represented as:

[0015]

[0016] , wherein is the observation signal vector, is the original signal vector, is the rotation frequency of the i th blade, is the number of rotations of the i th blade.

[0017] Preferably, in step S2, the three-dimensional tip clearance signal compressive sensing model is:

[0018]

[0019] wherein, is a sparse vector, is an observation signal, is a sensing matrix, the equation group is reduced by solving l The three-dimensional original signal is restored by solving the minimum value of the 0 norm.

[0020] Preferably, the sparse representation in the frequency domain is performed:

[0021]

[0022] wherein, Į T is a Fourier transform basis.

[0023] Preferably, the observation signal is:

[0024]

[0025] wherein, is an observation matrix.

[0026] Preferably, the observation matrix is:

[0027]

[0028] wherein, M is the number of rows, N is the number of columns, the number of rows M is much smaller than the number of columns N , each row contains only one 1 and the rest are 0.

[0029] Preferably, in step S3, the correlation coefficient is specifically:

[0030]

[0031] wherein, D is a sensing matrix, and are different two columns of the sensing matrix, and are the numbers of the different two columns.

[0032] In a second aspect, the embodiment of the present application provides an aero-engine three-dimensional blade tip clearance signal undersampling fractal dimension reconstruction system, comprising:

[0033] A signal module, for a three-dimensional blade tip clearance undersampling signal, calculates a theoretical arrival time of a blade passing through a sensor, and establishes a sampling model of a measurement signal;

[0034] A derivation module, by constructing a Fourier sparse matrix, represents a three-dimensional blade tip clearance original signal in a form of a plurality of harmonic superpositions, performs sparse representation in a frequency domain, and derives an observation matrix according to the sampling model to establish a three-dimensional blade tip clearance signal compressive sensing model;

[0035] A reconstruction module, by selecting a number of three-dimensional blade tip clearance sensors according to a correlation coefficient minimization theory, optimizes installation positions of the sensors, obtains an optimal sampling model of the three-dimensional blade tip clearance signal, constructs an optimal observation matrix according to the obtained optimal sampling model, inputs the optimal observation matrix into the compressive sensing model, and solves to obtain the three-dimensional blade tip clearance original signal.

[0036] 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, and the processor implements steps of the above-mentioned aero-engine three-dimensional blade tip clearance signal undersampling fractal dimension reconstruction method when executing the computer program.

[0037] In a fourth aspect, the embodiment of the present application provides a computer readable storage medium comprising a computer program, and the computer program implements steps of the above-mentioned aero-engine three-dimensional blade tip clearance signal undersampling fractal dimension reconstruction method when executed by a processor.

[0038] In a fifth aspect, a chip comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements steps of the above-mentioned aero-engine three-dimensional blade tip clearance signal undersampling fractal dimension reconstruction method when executing the computer program.

[0039] In a sixth aspect, the embodiment of the present application provides an electronic device comprising a computer program, and the computer program implements steps of the above-mentioned aero-engine three-dimensional blade tip clearance signal undersampling fractal dimension reconstruction method when executed by the electronic device.

[0040] Compared with the prior art, the present application has at least the following beneficial effects:

[0041] The three-dimensional blade tip gap signal undersampling dimension reconstruction method of an aero-engine is used for establishing a three-dimensional blade tip gap signal compressed sensing model for the three-dimensional blade tip gap undersampling signal, solving the reconstructed three-dimensional blade tip gap original signal, and then depicting the blade tip characteristics from the radial gap, axial deflection angle and circumferential slip angle three dimensions to extract the full-range fault information of the blade.

[0042] Further, the sampling process of the three-dimensional blade tip gap measurement signal is established, so that the observation matrix is constructed.

[0043] Further, the compressed sensing model of the three-dimensional blade tip gap signal is established, and the three-dimensional blade tip gap original signal is reconstructed by solving the minimum value of the sparse vector l 0 norm.

[0044] Further, the number of three-dimensional blade tip gap sensors is selected by the correlation coefficient minimization theory, and the installation position of the sensors is optimized.

[0045] It can be understood that the beneficial effects of the above-mentioned second aspect to the sixth aspect can be referred to the related description in the above-mentioned first aspect, which will not be repeated here.

[0046] In summary, the three-dimensional original signal is obtained by performing dimension reconstruction on the three-dimensional blade tip gap undersampling signal, so that the three-dimensional blade tip gap dynamic response characteristics are restored, which is beneficial to the full-range extraction of the blade crack fault characteristics of the three-dimensional blade tip gap, and provides theoretical guidance for the aero-engine blade crack quantitative diagnosis based on the three-dimensional blade tip gap.

[0047] The technical solutions of the present application will be further described in detail below with the help of the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 The method flowchart of the present application;

[0049] Figure 2 The sampling model schematic diagram of the three-dimensional blade tip gap measurement signal in the present application;

[0050] Figure 3 The compressed sensing model schematic diagram of the three-dimensional blade tip gap signal in the present application;

[0051] Figure 4 The simulation optimization comparison schematic diagram of the installation position of the three-dimensional blade tip gap sensor in the present application;

[0052] Figure 5 The overall design schematic diagram of the three-dimensional blade tip gap signal accurate measurement system in the present application;

[0053] Figure 6 Fig. 1 is a schematic diagram of a sensor static calibration module of a three-dimensional tip clearance signal precision measurement host computer software system according to the present application;

[0054] Figure 7 Fig. 2 is a schematic diagram of a sensor signal acquisition and display module of a three-dimensional tip clearance signal precision measurement host computer software system according to the present application;

[0055] Figure 8 Fig. 3 is a schematic diagram of a measurement signal decoupling module of a three-dimensional tip clearance signal precision measurement host computer software system according to the present application;

[0056] Figure 9 Fig. 4 is a schematic diagram of a measurement signal processing and fractal reconstruction module of a three-dimensional tip clearance signal precision measurement host computer software system according to the present application;

[0057] Figure 10 Fig. 5 is a schematic diagram of a computer device according to an embodiment of the present application;

[0058] Figure 11 Fig. 6 is a block diagram of a chip according to an embodiment of the present application;

[0059] Figure 12 Fig. 7 is a time domain reconstruction result diagram;

[0060] Figure 13 Fig. 8 is a frequency domain reconstruction result diagram. DETAILED DESCRIPTION

[0061] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0062] In the description of the present application, it should be understood that the terms "include" and "contain" indicate the presence of described features, whole, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, whole, steps, operations, elements, components and / or sets thereof.

[0063] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, unless otherwise clearly indicated by the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0064] It should be further understood that the term "and / or" as used herein refers to a 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 mean: A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0065] It should be understood that, although the terms first, second, third, etc. can be used in embodiments of the present application to describe a certain range, etc., these ranges should not be limited to these terms. These terms are only used to distinguish the ranges from each other. For example, the first preset range can also be referred to as the second preset range, and similarly, the second preset range can also be referred to as the first preset range without departing from the scope of the embodiments of the present application.

[0066] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if it is determined" or "if (a stated condition or event) is detected" can be interpreted to mean "when it is determined" or "in response to determining" or "when (a stated condition or event) is detected" or "in response to detecting (a stated condition or event)".

[0067] Various structural diagrams according to the disclosed embodiments of the present application are shown in the accompanying drawings. These drawings are not drawn to scale, in which certain details are exaggerated for the purpose of clarity and certain details can be omitted. The shapes of various regions, layers and their relative size and positional relationship shown in the drawings are only exemplary, and in actuality, they can be deviated due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers with different shapes, sizes and relative positions according to actual needs.

[0068] The present application provides a three-dimensional tip clearance signal undersampling fractal reconstruction method for an aero-engine, which establishes a sampling model of the measurement signal for the three-dimensional tip clearance undersampling signal; through constructing a Fourier sparse matrix, the original signal is sparsely represented in the frequency domain, and an observation matrix is derived to establish a three-dimensional tip clearance signal compressed sensing model; the number of three-dimensional tip clearance sensors is selected through correlation coefficient minimization theory, and the sensor installation position is optimized; and theoretical guidance is provided for quantitative diagnosis of aero-engine blade cracks based on three-dimensional tip clearance.

[0069] Referring to Figure 1 The three-dimensional tip clearance signal undersampling fractal reconstruction method for an aero-engine provided by the present application comprises the following steps:

[0070] S1. For the undersampled signal of the three-dimensional blade tip gap, calculate the theoretical arrival time of the blade passing through the sensor and establish a sampling model of the measurement signal.

[0071] Please see Figure 2 The theoretical arrival time of the blades over the sensor is used to establish a sampling model for the measurement signal.

[0072] from J Select from the locations where a three-dimensional blade tip clearance sensor can be installed K Sensors are installed at [number] locations, with the number of sensors being [number]. K Let there be , and the sampling sequence for the sensor installation location be . ,in a k For the first k The installation locations of the sensors meet the following requirements: The sampling model of the three-dimensional tip clearance signal is then expressed as: ( J , K , A The rotational frequency of the blades is... f r According to the sampling model ( J , K , A ),blade i Rotate the first n During the lap, after the first k The theoretical arrival time of each sensor is expressed as:

[0073] (1)

[0074] No. k The installation angle of each sensor is α k The theoretical arrival time is expressed as:

[0075] (2)

[0076] The signal sampling process is represented as follows:

[0077] (3)

[0078] in, The original signal vector, h x ( t ), α x ( t ), β x ( t These are the original signals for radial clearance, axial deflection angle, and circumferential slip angle, respectively. For the observed signal vector,h y ( n ), α y ( n ), β y ( n ) are the radial gap, axial deflection angle and circumferential slip angle measurement signals respectively.

[0079] S2, by constructing Fourier sparse matrix, the three-dimensional tip clearance original signal is expressed as a form of superposition of multiple harmonics, so as to carry out sparse representation in frequency domain, and the observation matrix is derived according to the sampling model, and the three-dimensional tip clearance signal compressed sensing model is established;

[0080] Please refer to Figure 3 , according to the characteristics of the multi-frequency combination of the dynamic response of the three-dimensional tip clearance signal, the signal is expressed as a form of superposition of multiple harmonics:

[0081] (4)

[0082] Wherein, is the amplitude vector of the dynamic response of the three-dimensional tip clearance signal, is the frequency vector, is the phase vector, M is the number of harmonic superposition.

[0083] The Fourier transform of formula (4) is carried out by using the sparse characteristics of the signal in the frequency domain, and then the signal is carried out sparse representation in the frequency domain:

[0084] (5)

[0085] Wherein, Ѱ T is the Fourier transform base, that is, the sparse matrix, is the sparse vector, h θ ( f ), α θ ( f ), β θ ( f ) are the radial gap, axial deflection angle and circumferential slip angle frequency domain sparse values respectively, each row contains only a small number of non-zero elements, and the number of non-zero elements is the sparsity.

[0086] From formula (3), the observation signal is obtained by regularly sampling from the original signal according to the sampling mode, and is expressed as:

[0087] (6)

[0088] Wherein, The observation matrix has the following number of rows. M Much smaller than its number of columns N Each line contains only one 1, and the rest are 0.

[0089] The observed signal is further represented as:

[0090] (7)

[0091] in, This is the sensing matrix.

[0092] Therefore, the following three-dimensional compressed sensing model for blade tip clearance signals is established:

[0093] (8)

[0094] This system of equations is solved by... l The minimum value of the 0 norm is used to restore the original signal.

[0095] S3. Select the number of three-dimensional blade tip clearance sensors by minimizing the correlation coefficient and optimize the sensor installation position.

[0096] Please see Figure 4 For sampling three-dimensional blade tip gap signals, the constructed observation matrix is ​​a specific matrix constructed according to a certain rule. The rule is related to the number and arrangement of sensors. Determining whether a general matrix satisfies the RIP characteristic is an NP-hard problem and cannot be solved.

[0097] The correlation coefficient is used to describe the correlation between columns of a matrix, and is defined as follows:

[0098] (9)

[0099] Where D is the sensing matrix. By optimizing the sensor arrangement, the correlation between columns D is reduced, thereby increasing the probability of the signal being accurately reconstructed.

[0100] A finite element model of the rotor system was established using Ansys finite element analysis software to obtain the three-dimensional blade tip clearance simulation signal. The reconstruction power of the three-dimensional blade tip clearance signal was compared by simulation under different numbers of sensors. The number of three-dimensional blade tip clearance sensors was initially selected. The sensor installation position was optimized according to the correlation coefficient minimization theory to obtain the optimal sampling model of the three-dimensional blade tip clearance signal.

[0101] Please see Figure 5, three-dimensional blade tip clearance signal precision measurement hardware system, including three-dimensional blade tip clearance optical fiber sensor, light source drive circuit and signal conditioning circuit; Firstly, select three-dimensional blade tip clearance optical fiber sensor, for double coil coaxial optical fiber sensor, according to the optimal sampling model on the casing according to a certain angle installation multiple, for obtaining measurement signal; Secondly, the design of light source drive circuit is used for providing light source for the multiple incident optical fibers of sensor probe, the circuit model simulation of light source circuit is established in Multisim software, the light power of multiple light sources is ensured and stable; Then design signal conditioning circuit, mainly for photoelectric conversion module, for converting the light intensity signal output by the optical fiber into voltage signal output, through simulation, the output consistency of multiple conditioning circuits is good; Finally, according to the circuit schematic diagram, the printed circuit board wiring is carried out by using Altium Designer software.

[0102] The three-dimensional blade tip clearance signal precision measurement host computer software system includes a sensor static calibration module, a sensor signal acquisition and display module, a measurement signal decoupling module, and a measurement signal processing and fractal reconstruction module.

[0103] Please refer to Figure 6 , which is a sensor static calibration module software design diagram, used for calibration of optical fiber sensor, and stores the pre-trained network.

[0104] Please refer to Figure 7 , which is a sensor signal acquisition and display module design diagram, used for recording and displaying the voltage signals output by multiple optical fiber sensors and phase detection sensors.

[0105] Please refer to Figure 8 , which is a measurement signal decoupling module design diagram, used for decoupling of the voltage output values of multiple optical fiber sensors to obtain three-dimensional blade tip clearance measurement signals.

[0106] Please refer to Figure 9 , which is a measurement signal processing and fractal reconstruction module design diagram, used for processing and fractal reconstruction of three-dimensional blade tip clearance measurement signals.

[0107] LabVIEW is used to design the three-dimensional blade tip clearance signal precision measurement host computer software system. Firstly, the sensor static calibration module is designed for calibration of the optical fiber sensor. The voltage output value of the sensor and the three-dimensional blade tip clearance value are input into the neural network for training by calling the MatLab script, and the pre-trained network is stored.

[0108] Secondly, the sensor signal acquisition and display module is designed to acquire and display the voltage signals output by multiple optical fiber sensors and phase detection sensors. The sampling rate and sampling number are set, the recording mode is opened, the outputs of multiple sensors are recorded and stored, and the data length is displayed.

[0109] Then the measurement signal decoupling module is designed, the voltage output values of the multiple optical fiber sensors are decoupled through a pre-trained neural network by calling a MatLab script, three-dimensional blade tip clearance measurement values are acquired and displayed, the required signal length is set, and data is stored;

[0110] Finally, the measurement signal processing and dimension reconstruction module is designed, the three-dimensional blade tip clearance measurement values of the multiple sensors are segmented and processed by calling a MatLab script, three-dimensional blade tip clearance measurement values of a certain blade are acquired and stored, dimension reconstruction is performed, three-dimensional blade tip clearance original signals of the certain blade are obtained and stored.

[0111] In another embodiment of the present application, an aero-engine three-dimensional blade tip clearance signal undersampling dimension reconstruction system is provided, which can be used to realize the aero-engine three-dimensional blade tip clearance signal undersampling dimension reconstruction method.

[0112] The signal module calculates the theoretical arrival time of the blade passing through the sensor for the three-dimensional blade tip clearance undersampling signal, and establishes a sampling model of the measurement signal;

[0113] The derivation module represents the three-dimensional blade tip clearance original signal in the form of multiple harmonic superpositions by constructing a Fourier sparse matrix, performs sparse representation in the frequency domain, and derives an observation matrix according to the sampling model to establish a three-dimensional blade tip clearance signal compressed sensing model;

[0114] The reconstruction module selects the number of three-dimensional blade tip clearance sensors by the correlation coefficient minimization theory, optimizes the installation position of the sensors, obtains an optimal sampling model of the three-dimensional blade tip clearance signal, constructs an optimal observation matrix according to the obtained optimal sampling model, inputs the compressed sensing model, and solves to obtain the three-dimensional blade tip clearance original signal.

[0115] In another embodiment of the present application, a terminal device is provided, which comprises a processor and a memory, the memory is configured to store a computer program, the computer program comprises program instructions, and the processor is configured to execute the program instructions stored in the computer storage medium. The processor can be a central processing unit (CPU), and can also be other general-purpose 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, discrete hardware components, etc., which are the computing core and control core of the terminal, and are suitable for implementing one or more instructions, and are particularly suitable for loading and executing one or more instructions to implement a corresponding method flow or a corresponding function; the processor in the embodiments of the present application can be used for the operation of the three-dimensional tip clearance signal undersampling fractal reconstruction method of an aero-engine, including:

[0116] For the three-dimensional tip clearance undersampling signal, the theoretical arrival time of the blade passing through the sensor is calculated, and a sampling model of the measurement signal is established; by constructing a Fourier sparse matrix, the three-dimensional tip clearance original signal is expressed in the form of a plurality of harmonic superpositions, a sparse representation in the frequency domain is performed, and an observation matrix is derived according to the sampling model to establish a three-dimensional tip clearance signal compressed sensing model; the number of three-dimensional tip clearance sensors is selected by the correlation coefficient minimization theory, and the installation position of the sensor is optimized to obtain an optimal sampling model of the three-dimensional tip clearance signal, an optimal observation matrix is constructed according to the obtained optimal sampling model, and is input into the compressed sensing model to obtain the three-dimensional tip clearance original signal.

[0117] Please refer to Figure 10 , the terminal device is a computer device, the computer device 60 of the embodiment comprises a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61, and the computer program 63 implements the fluid composition calculation method in the reservoir stimulation wellbore in the embodiment when executed by the processor 61, to avoid repetition, which will not be described here. Alternatively, the computer program 63 implements the functions of each model / unit in the three-dimensional tip clearance signal undersampling fractal reconstruction system of the aero-engine in the embodiment when executed by the processor 61, to avoid repetition, which will not be described here.

[0118] The computer device 60 can be a desktop computer, a notebook computer, a palm computer, a cloud server, and the like. The computer device 60 can include, but is not limited to, a processor 61, a memory 62. Those skilled in the art can understand that Figure 8 The computer device 60 is only an example and does not constitute a limitation on the computer device 60, and can include more or fewer components than shown, or combine certain components, or different components, for example, the computer device can also include an input / output device, a network access device, a bus, and the like.

[0119] The processor 61 can be a central processing unit (CPU), and can also be 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, and the like. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0120] The memory 62 can be an internal storage unit of the computer device 60, such as a hard disk or a memory of the computer device 60. The memory 62 can 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, and the like.

[0121] Further, the memory 62 can include both an internal storage unit and an external storage device of the computer device 60. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 can also be used to temporarily store data that has been output or will be output.

[0122] Please refer to Figure 11 The terminal device is a chip, and the chip 600 of the embodiment includes a processor 622, the number of which can be one or more, and a memory 632 for storing a computer program executable by the processor 622. The computer program stored in the memory 632 can include one or more than one module each corresponding to a set of instructions. In addition, the processor 622 can be configured to execute the computer program to perform the above-mentioned aero-engine three-dimensional tip clearance signal under-sampling fractal reconstruction method.

[0123] In addition, the chip 600 can further include a power component 626, which can be configured to perform power management of the chip 600, and a communication component 650, which can be configured to implement communication of the chip 600, for example, wired or wireless communication. In addition, the chip 600 can further include an input / output interface 658. The chip 600 can operate based on an operating system stored in the memory 632.

[0124] In another embodiment of the present application, the present application further provides a storage medium, specifically a computer readable storage medium, which is a memory device in a terminal device, used for storing programs and data. It can be understood that the computer readable storage medium herein can include an internal storage medium of the terminal device, and of course can also include an expansion storage medium supported by the terminal device. The computer readable storage medium provides a storage space, which stores an operating system of the terminal. In addition, one or more instructions adapted to be loaded and executed by the processor are also stored in the storage space, and the instructions can be one or more computer programs. It should be noted that the computer readable storage medium herein can be a high-speed RAM memory, or a non-volatile memory such as at least one disk memory.

[0125] The one or more instructions stored in the computer readable storage medium can be loaded and executed by the processor to implement the corresponding steps of the method for reconstructing the under-sampled fractal dimension of the three-dimensional blade tip clearance signal of the aero-engine in the above embodiments. The one or more instructions stored in the computer readable storage medium are loaded and executed by the processor as follows:

[0126] The theoretical arrival time of the blade passing through the sensor is calculated for the three-dimensional blade tip clearance undersampling signal, and a sampling model of the measurement signal is established; the three-dimensional blade tip clearance original signal is expressed in the form of a plurality of harmonic superpositions by constructing a Fourier sparse matrix, sparse representation in the frequency domain is carried out, and an observation matrix is derived according to the sampling model to establish a three-dimensional blade tip clearance signal compressed sensing model; the number of three-dimensional blade tip clearance sensors is selected by the correlation coefficient minimization theory, and the installation position of the sensor is optimized to obtain an optimal sampling model of the three-dimensional blade tip clearance signal, and the optimal observation matrix is constructed according to the obtained optimal sampling model and input into the compressed sensing model to obtain the three-dimensional blade tip clearance original signal.

[0127] The three-dimensional blade tip clearance simulation signal is reconstructed by dimension, the normal signal and the fault signal of the blade with a crack are reconstructed respectively, the time domain reconstruction result is as shown in Figure 12 The frequency domain reconstruction result is as shown in Figure 13 The simulation result shows that the absolute error and the relative error of the reconstruction of the 3D-BTC signal are less than 1e-15, the radial gap signal, the axial deflection angle signal and the circumferential slip angle signal are accurately reconstructed, and the respective frequency spectrum is accurately restored, and the reconstruction performance is verified.

[0128] In summary, the three-dimensional blade tip clearance signal undersampling dimension reconstruction method and system of the aviation engine can obtain the three-dimensional original signal by reconstructing the three-dimensional blade tip clearance undersampling signal by dimension, so as to restore the three-dimensional blade tip clearance dynamic response characteristics, which is beneficial to comprehensively extract the blade crack fault characteristics of the three-dimensional blade tip clearance, realizes the non-contact rapid quantitative diagnosis of the blade crack, and has great significance for timely discovering the early weak crack of the turbine blade and ensuring flight safety.

[0129] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be realized in the form of hardware or software. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction, and do not limit the protection scope of the present application. The specific working process of the units and modules in the above system can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0130] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the related description of other embodiments.

[0131] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present application can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0132] In the embodiments provided by the present application, it should be understood that the disclosed devices / terminals and methods can be implemented by other ways. For example, the device / terminal embodiments described above are only schematic, and the division of the modules or units is only a logical function division, and there can be another division way in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed units can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0133] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0134] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0135] The integrated module / unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiment methods can be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. The computer program can implement the steps of each method embodiment when executed by a processor. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms. The computer readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the computer readable medium can include or exclude contents according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.

[0136] The present application is described with reference to flowcharts and / or block diagrams according to the methods, devices, and computer program products of embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The device that implements the functions specified in one flow or multiple flows and / or blocks Figure 1 The device that implements the functions specified in one flow or multiple flows and / or blocks

[0137] These computer program instructions can also be stored in a computer readable storage medium that can guide the computer or other programmable data processing devices to work in a specific way, so that the instructions stored in the computer readable storage medium produce a product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1one or more processes and / or blocks Figure 1 the function specified in the one or more blocks.

[0138] These computer program instructions can also be loaded into computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate a computer-implemented process, so that the instructions executed on the computer or other programmable data processing devices provide a process for implementing the flow Figure 1 one or more processes and / or blocks Figure 1 the function specified in the one or more blocks.

[0139] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A method for reconstructing a three-dimensional blade tip clearance signal of an aeroengine from an undersampled fractal dimension, characterized in that, The method comprises the following steps: S1, for the three-dimensional blade tip clearance undersampling signal, calculating the theoretical arrival time of the blade passing through the sensor, and establishing a sampling model of the measurement signal; S2, by constructing a Fourier sparse matrix, expressing the three-dimensional blade tip clearance original signal in the form of superposition of multiple harmonics, performing sparse representation in the frequency domain, and deriving an observation matrix according to the sampling model obtained in step S1, a three-dimensional blade tip clearance signal compressed sensing model is established, and the three-dimensional blade tip clearance signal compressed sensing model is: wherein, is a sparse vector, is an observation signal, is a sensing matrix; S3, by selecting the number of three-dimensional blade tip clearance sensors and optimizing the installation position of the sensors according to the correlation coefficient minimization theory, an optimal sampling model of the three-dimensional blade tip clearance signal is obtained, an optimal observation matrix is constructed according to the obtained optimal sampling model, and the three-dimensional blade tip clearance original signal is solved by inputting the compressed sensing model obtained in step S2, and the correlation coefficient is specifically: where D is a sensing matrix, and are two different columns of the sensing matrix D, and are the numbers of the two different columns.

2. The aeroengine 3D tip clearance signal sub-sampling fractal dimension reconstruction method of claim 1, wherein, In step S1, the sampling model of the measurement signal is specifically: According to the sampling process of the three-dimensional blade tip clearance of the aero-engine, the undersampling characteristics of the three-dimensional blade tip clearance measurement signal are derived; a sampling model of the three-dimensional blade tip clearance signal is established through the sampling sequence of the three-dimensional blade tip clearance virtual sensor, the actually installed sensor and the sensor installation position, and then the theoretical arrival time of the blade passing through a certain sensor is derived; and a mathematical model of the sampling of the three-dimensional blade tip clearance observation signal vector from the original signal vector is obtained.

3. The aeroengine 3D tip clearance signal sub-sampling fractal dimension reconstruction method of claim 2, wherein, From J one of the installable three-dimensional blade tip clearance sensor positions K one position installs the sensor, the sensor installs the number of K one, sets the sampling sequence of the sensor installation position as , a k is the installation position of the first k sensor, satisfies: Then the sampling model of three-dimensional blade tip clearance signal is expressed as: ( J , K , A ).

4. The method of claim 2, wherein, The sampling process of the signal is expressed as: wherein, is the observed signal vector, is the original signal vector, is the rotational frequency of the i th blade, is the number of revolutions of the i th blade.

5. The aeroengine 3-D tip clearance signal sub-N reconstruction method of claim 1, wherein, Sparse representation in the frequency domain is performed: wherein T is the Fourier transform basis.

6. The aeroengine 3-D tip clearance signal sub-sampling fractal dimension reconstruction method of claim 1, wherein, Observed signal is: wherein is an observation matrix.

7. The method of claim 6, wherein, Observation matrix is: wherein, M is the number of rows, N is the number of columns, the number of rows M is much smaller than the number of its columns N each row contains only one 1, and the rest are 0.

8. An aeroengine three-dimensional tip clearance signal undersampling fractal dimension reconstruction system, characterized by, It comprises: The signal module calculates the theoretical arrival time of the blade passing through the sensor for the three-dimensional blade tip clearance undersampling signal, and establishes a sampling model of the measurement signal; The derivation module, by constructing a Fourier sparse matrix, expresses the three-dimensional blade tip clearance original signal in the form of superposition of multiple harmonics, performs sparse representation in the frequency domain, and derives an observation matrix according to the sampling model, and establishes a three-dimensional blade tip clearance signal compressed sensing model, and the three-dimensional blade tip clearance signal compressed sensing model is: wherein, is a sparse vector, is an observation signal, is a sensing matrix; The reconstruction module, by selecting the number of three-dimensional blade tip clearance sensors and optimizing the installation position of the sensors according to the correlation coefficient minimization theory, an optimal sampling model of the three-dimensional blade tip clearance signal is obtained, an optimal observation matrix is constructed according to the obtained optimal sampling model, and the three-dimensional blade tip clearance original signal is solved by inputting the compressed sensing model obtained in step S2, and the correlation coefficient is specifically: where D is a sensing matrix, and are two different columns of the sensing matrix D, and are the column numbers of the two different columns.

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