Gear local fault vibration phenomenological modeling method, fault diagnosis method and system

Abstract

The present invention belongs to the technical field of gear fault diagnosis. A gear local fault vibration phenomenological modeling method, a fault diagnosis method and a system are provided. According to the location and size of the local fault, the time interval #imgabs0# between the start and the end of the local fault is calculated; a rectangular window function with a window width of #imgabs1# is used to simulate the modulation response caused by the local fault; two impulse functions with an interval of #imgabs2# are used to simulate the impulse response caused by the local fault; and the sum of the modulation response and the impulse response is used as the total response of the system vibration signal caused by the local fault. The present invention can not only accurately simulate the modulation effect caused by the fault, but also capture the transient impulse response when the fault occurs, accurately calculate the time point when the fault occurs, determine the time width of the rectangular window and the time interval between the impulse response, so as to achieve more accurate fault simulation and fault diagnosis.

Description

Technical Field

[0001] The present invention relates to the technical field of gear fault diagnosis, and in particular to a gear local fault vibration phenomenological modeling method, a fault diagnosis method and a system. Background Art

[0002] The statements in this section merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] Gear meshing constitutes the basic unit of complex gear systems, especially in key applications such as wind power gearboxes, such as "one-stage planetary + two-stage fixed shaft" and "two-stage planetary + one-stage fixed shaft" structures. In-depth understanding of the vibration signal generation mechanism and its characteristic manifestation of single-stage fixed shaft gear trains is crucial for studying complex multi-stage gear transmission systems. By establishing a vibration signal model, the vibration response of the system under different health states can be obtained, and the mapping relationship between the vibration signal characteristics and the system fault state can be clarified, providing a theoretical basis for fault diagnosis.

[0004] Under long-term harsh working conditions such as speed change, heavy load and frequent impact, the gear system is prone to local faults such as cracks and broken teeth. If the fault cannot be diagnosed in a timely and accurate manner, it may lead to a cascading fault effect, causing the entire transmission system to lose function and causing significant economic losses. At present, fault diagnosis methods based on vibration signals mostly rely on dynamic modeling. These methods are usually designed for specific parameter systems and are highly dependent on the certainty and accuracy of system parameters, resulting in low modeling efficiency and lack of universality.

[0005] To solve this problem, researchers began to explore new perspectives from the perspective of phenomenological modeling and proposed a variety of methods including the AM-FM model and the impulse response model.

[0006] For example, an existing technology proposes a step-impact vibration phenomenological modeling method for spur gear spalling faults, aiming to provide theoretical support for the diagnosis of such faults. This technology uses a step function to simulate the step response of the spur gear when it enters the fault area in the spalling state, and an impulse function to simulate the impulse response when it exits the fault area. However, this technology only considers the impulse response caused by the spalling fault when modeling, and does not involve the modulation response that may be caused by the fault.

[0007] For another example, another existing technology provides a phenomenological modeling method for a normal single-stage epicyclic gear train taking into account the meshing phase difference. This technology focuses on establishing a phenomenological model of the vibration signal of the epicyclic gear train, taking into account the phase difference between multiple planetary gear-sun gear and planetary gear-ring gear meshing pairs, as well as the time-varying transmission path of the epicyclic gear train. This technology focuses on solving the phase and time-varying path problems caused by the particularity of the epicyclic gear train structure, and does not involve the failure problem of the meshing gears.

[0008] For another example, in order to explain the vibration characteristic generation mechanism of vibration signals in the time domain and frequency domain, researchers proposed using rectangular windows to simulate local faults of gears. However, this modeling method only focuses on the modulation effect caused by local faults, while ignoring the impact effect caused by local faults. This results in limited explanation of the generation mechanism of the frequency characteristics of vibration signals, which can easily lead to misdiagnosis of faults.

[0009] In general, traditional modeling methods tend to focus only on the single modulation response or impulse response caused by local faults, and often ignore the changes in fault time characteristics caused by the specific location and size of the fault during modeling, resulting in insufficient explanation of the time domain and frequency characteristics of the vibration signal. Summary of the invention

[0010] In order to address the deficiencies in the prior art, the present invention provides a gear local fault vibration phenomenological modeling method, a fault diagnosis method and a system. By combining a variable window width rectangular window and an impulse function, it is not only possible to accurately simulate the modulation effect caused by the fault, but also to capture the transient impulse response when the fault occurs. By comprehensively analyzing the fault type and location, the time point of the fault occurrence can be accurately calculated, and the time width of the rectangular window and the time interval between the impulse response can be determined, thereby achieving more accurate fault simulation and fault diagnosis.

[0011] In order to achieve the above object, the present invention adopts the following technical solution:

[0012] In a first aspect, the present invention provides a method for phenomenological modeling of gear local fault vibration

[0013] A phenomenological modeling method for local fault vibration of gears includes the following processes:

[0014] Calculate the time interval between the start and end of a local fault based on the location and size of the local fault ;

[0015] Using the window width The rectangular window function is used to simulate the modulation response caused by local faults;

[0016] Use two intervals for The impulse function is used to simulate the impulse response caused by local faults;

[0017] The sum of the modulation response and the impulse response is used as the total response of the system vibration signal caused by the local fault.

[0018] As a further limitation of the first aspect of the present invention, the angle of rotation of the gear when the local fault begins to mesh is calculated and the angle of rotation of the gears when the meshing ends , local fault start time and fault end time They are: , , and Respectively represent the rotation frequency of the driving wheel and the driven wheel; the time interval between the start and end of the fault for: .

[0019] As a further limitation of the first aspect of the present invention, the modulation response caused by the local fault is: ,in, (1, 2, ···, ) is the meshing vibration harmonic order, For the The amplitude of the harmonic of meshing vibration, For the The phase of the harmonics of the meshing vibration, is the meshing frequency, represents the pulse train caused by a local fault, t For the current moment.

[0020] As a further limitation of the first aspect of the present invention ,in, Indicates the pulse train number caused by local fault, I represents the total number of pulse trains caused by local faults, is the pulse amplitude, is the rotation period of the faulty gear, It is the moment when the first pulse caused by local fault enters meshing. The moment when the first pulse caused by a local fault ends the meshing, The local fault caused i The moment a pulse enters meshing, The local fault caused i The moment when the pulse ends the meshing.

[0021] As a further limitation of the first aspect of the present invention, the impulse response caused by the local fault includes: ,in, represents the natural frequency of the faulty gear, represents the damping coefficient, and represents the impulse response amplitude caused by local faults, and the mod function is the remainder function. It is the moment when the first pulse caused by local fault enters meshing. The moment when the first pulse caused by a local fault ends the meshing, is the rotation period of the faulty gear.

[0022] In a second aspect, the present invention provides a gear local fault vibration phenomenological modeling system.

[0023] A gear local fault vibration phenomenological modeling system, comprising:

[0024] A fault interval calculation unit is configured to calculate the time interval between the start and end of the local fault according to the location and size of the local fault ;

[0025] The modulation response simulation unit is configured to: use a window width of The rectangular window function is used to simulate the modulation response caused by local faults;

[0026] The impulse response simulation unit is configured as follows: using two intervals of The impulse function is used to simulate the impulse response caused by local faults;

[0027] The phenomenological modeling signal generating unit is configured to: use the sum of the modulation response and the impulse response as the total response of the system vibration signal caused by the local fault.

[0028] As a further limitation of the second aspect of the present invention, in the modulation response simulation unit, the modulation response caused by the local fault is: ,in, (1, 2, ···, ) is the meshing vibration harmonic order, For the The amplitude of the harmonic of meshing vibration, For the The phase of the harmonics of the meshing vibration, is the meshing frequency, represents the pulse train caused by a local fault, t For the current moment.

[0029] As a further limitation of the second aspect of the present invention, in the impulse response simulation unit, the modulation response caused by the local fault includes: ,in, represents the natural frequency of the faulty gear, represents the damping coefficient, and represents the impulse response amplitude caused by local faults, and the mod function is the remainder function. It is the moment when the first pulse caused by local fault enters meshing. The moment when the first pulse caused by a local fault ends the meshing, is the rotation period of the faulty gear.

[0030] In a third aspect, the present invention provides a method for diagnosing local faults of gears.

[0031] A method for diagnosing local faults of gears includes the following steps:

[0032] According to the basic parameters of the gear system under test and the total response model of the system vibration signal established by the gear local fault vibration phenomenological modeling described in the first aspect of the present invention, local faults at different locations and different degrees are simulated to determine the mapping relationship between the vibration signal characteristics and the gear system fault state, and obtain the a priori spectrum structure;

[0033] According to the actual monitored gear system vibration information, the time domain waveform and spectrum structure of the measured signal are recorded. When periodic pulses appear in the time domain waveform of the measured signal, and the interval of the periodic pulses corresponds to the rotation period of the passive wheel, it is preliminarily determined that a local fault has occurred.

[0034] The spectrum structure of the measured signal is compared with the a priori spectrum structure. If the two are consistent or the difference is within the set range, it is ultimately determined that a local fault has occurred in the gear component of the gear system.

[0035] In a fourth aspect, the present invention provides a gear local fault diagnosis system.

[0036] A gear local fault diagnosis system, comprising:

[0037] The a priori spectrum structure generating unit is configured to: simulate local faults at different positions and different degrees based on basic parameters of the gear system under test and a total response model of the system vibration signal established by using the gear local fault vibration phenomenological modeling described in the first aspect of the present invention, determine the mapping relationship between the vibration signal characteristics and the gear system fault state, and obtain the a priori spectrum structure;

[0038] The local fault preliminary judgment unit is configured to: record the time domain waveform and spectrum structure of the measured signal according to the actually monitored gear system vibration information, and preliminarily judge that a local fault occurs when a periodic pulse appears in the time domain waveform of the measured signal, and the interval of the periodic pulse corresponds to the rotation period of the driven wheel;

[0039] The local fault final judgment unit is configured to compare the spectrum structure of the measured signal with the a priori spectrum structure. If the two are consistent or the difference is within a set range, it is finally judged that a local fault occurs in the gear component of the gear system.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. Comprehensively capture the modulation and impulse response of local gear faults: By combining a variable width rectangular window and an impulse function, this method can not only accurately simulate the modulation effect caused by the fault, but also capture the transient impulse response when the fault occurs. Specifically, the present invention uses a variable width rectangular window to simulate the modulation response, and uses an impulse function to describe the impulse response at the beginning and end of the fault; by comprehensively analyzing the fault type and location, the present invention can accurately calculate the time point when the fault occurs, determine the time width of the rectangular window and the time interval between the impulse response, thereby providing a more accurate fault simulation method.

[0042] 2. Significantly improved signal characterization capabilities: Compared with traditional methods that rely solely on single modulation or impulse modeling, the method of the present invention can provide a more comprehensive interpretation of the signal spectrum. This comprehensive interpretation significantly improves the accuracy and reliability of fault diagnosis and reduces the risk of misdiagnosis due to unclear frequency components.

[0043] 3. Ease of use of modeling parameters: The modeling ideas and parameters adopted by the present invention are easier to calculate and obtain than traditional modeling methods such as concentrated parameter dynamics. This ease of use not only simplifies the modeling process, but also improves the practicality and operability of the model, making the present invention more efficient and convenient in practical applications.

[0044] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0046] Figure 1 A schematic flow chart of a method for phenomenological modeling of local gear fault vibration provided in Example 1 of the present invention;

[0047] Figure 2 A schematic diagram of the meshing position of a gear pair under a local fault provided in Example 1 of the present invention;

[0048] Figure 3 The gear local fault model simulation signal waveform and its spectrum provided in Example 1 of the present invention;

[0049] Figure 4 The signal waveform and spectrum of the gear local fault experiment provided in Example 1 of the present invention;

[0050] Figure 5 A schematic diagram of the principle of a gear local fault vibration phenomenological modeling system provided in Example 2 of the present invention;

[0051] Figure 6 A schematic flow chart of a method for diagnosing local gear faults provided in Example 3 of the present invention;

[0052] Figure 7 This is a schematic diagram of the principle of the gear local fault diagnosis system provided in Example 4 of the present invention. DETAILED DESCRIPTION

[0053] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0054] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0055] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0056] Embodiment 1:

[0057] In view of what is described in the background technology, a single modulation and impact modeling method can only provide the generation mechanism of some frequency components in the vibration signal spectrum, but cannot provide a comprehensive explanation of the frequency components of the vibration signal, which is easy to lead to misdiagnosis due to unclear frequency sources. The gear local fault vibration phenomenological modeling method proposed in the present invention conducts comprehensive modeling of two typical vibration responses caused by gear local faults, namely, modulation response and impact response. Compared with the traditional single modulation and impact modeling method, it has stronger signal characterization capabilities. Specifically, a variable window width rectangular window is used to simulate the modulation response caused by a gear local fault, and an impact function is used to describe the system impact response caused by the start and end of the local fault; then, the specific type and location of the local fault are used to calculate the time window width of the variable window width rectangular window and the time interval between the two impact responses; on this basis, a vibration phenomenological model of the gear local fault is established, which can reveal the generation mechanism of the vibration characteristics under the gear local fault on the one hand, and provide a theoretical basis for the diagnosis of local faults in the gear system on the other hand.

[0058] More specifically, the gear local fault vibration phenomenological modeling method described in this implementation is as follows: Figure 1 As shown, the following process is included:

[0059] S1.1: Calculate the start and end times of local faults and determine the time interval .

[0060] Setting of initial moment and reference point: First, select the moment when the faulty tooth begins to mesh as the initial moment, such as Figure 2As shown in the figure, the initial meshing point of the faulty tooth is defined as point A, and the meshing moment of point A is taken as the zero moment. .

[0061] Figure 2 In the figure, the lower gear is the driving gear (represented by gear 1), the upper gear is the driven gear (represented by gear 2), and the theoretical meshing line starts at point M point and ends at point N Point represents the contact trajectory of the two gear tooth profiles under ideal conditions. Fault starting point and failure termination point The start and end positions of local faults on the involute tooth profile are identified; and for and Projection on the meshing line, where , , base circle tangent point B and C Fault Points and The intersection of the tangent line to the base circle and the base circle, where the straight line OB and Vertical, straight line OC and vertical, and Respectively represent the addendum circle and root circle of the corresponding gear. For example, the addendum circle and root circle of gear 1 are expressed as and .

[0062] According to the geometric relationship of involute gear, calculate:

[0063] (1);

[0064] In formula (1), and are the pitch circle radii of the active and passive gears respectively; and is the radius of the addendum circle and root circle of the passive gear; is the root circle radius of the driving gear teeth.

[0065] Based on the above parameters, calculate the angle of gear rotation when the local fault begins to mesh and the angle of gear rotation when the meshing ends :

[0066] (2);

[0067] (3);

[0068] in, is the location where the local fault starts on the involute gear.

[0069] Therefore, the time when the local fault first starts to enter the mesh and exit the mesh is expressed as:

[0070] (4);

[0071] (5);

[0072] Failure time interval :

[0073] (6);

[0074] In the formula, and They represent the time when the local fault first starts to enter meshing and exit meshing; and Respectively represent the rotation frequency of the driving wheel and the driven wheel.

[0075] S1.2: Using a window width of The rectangular window simulates the modulation response caused by local fault.

[0076] S1.2.1: Pulse sequence caused by local fault:

[0077] A local fault can be represented as a series of pulses, Represents a pulse train caused by a local fault:

[0078] (7);

[0079] in, Indicates the pulse train number caused by local fault, I represents the total number of pulse trains caused by local faults, is the pulse amplitude, is the rotation period of the faulty gear, It is the moment when the first pulse caused by local fault enters meshing. The moment when the first pulse caused by a local fault ends the meshing, The local fault caused i The moment a pulse enters meshing, The local fault caused i The moment when the pulse ends the meshing.

[0080] S1.2.2: Mathematical expression of the modulation response.

[0081] The modulation response caused by a local fault is expressed as:

[0082] (8);

[0083] In the formula, (1,2,…, ) is the meshing vibration harmonic order; and For the Amplitude and phase of the harmonics of meshing vibration; is the meshing frequency.

[0084] S1.3: Use two intervals The impulse function simulates the impulse response caused by local faults, specifically:

[0085] (9);

[0086] In the formula, Represents the natural frequency of the faulty gear; represents the damping coefficient; and Represents the impulse response amplitude caused by local fault.

[0087] S1.4: Synthesis of the total response of the system vibration signal.

[0088] The total response of the system vibration signal caused by a local fault is the superposition of the modulation response and the impulse response. The total response can be expressed as:

[0089] (10).

[0090] Through the above steps, the present invention can construct a vibration signal model that comprehensively considers the modulation effect and the impact effect. It not only comprehensively considers the two responses caused by the fault, but also adjusts the time characteristics of the fault according to the location and size of the fault, thereby significantly improving the signal characterization capability and providing a comprehensive signal characterization for the diagnosis and analysis of gear faults.

[0091] This implementation method describes in detail the vibration signal model established by the present invention in conjunction with specific examples.

[0092] Experimental setup: Consider a fixed-axis gear system, where the active gear has 29 teeth and the passive gear has 95 teeth. Assume that the fault is a broken tooth fault, which occurs on the passive gear. The input frequency of the gearbox is 50Hz, so the system meshing frequency is 1450Hz, and the rotation frequencies of the active and passive gears are 50Hz and 15.26Hz respectively. When a broken tooth fault occurs on a gear, the moment when the fault begins to occur is the moment when the active and passive gears begin to mesh, that is, The moment when the fault ends is the moment when the top circle of the driving wheel and the driven wheel mesh. (In the formula represents the gear overlap).

[0093] Model parameter setting: Set the model simulation parameters, as shown in Table 1, including meshing frequency harmonic components, amplitude, initial phase, overlap, rectangular window amplitude, impulse response amplitude, system natural frequency, and system damping coefficient.

[0094] Table 1: Model parameter settings

[0095]

[0096] Substitute the above parameters into the vibration signal model, Figure 3 The model simulation signal and its spectrum obtained based on this method are shown, where: Figure 3 (a) is the time domain waveform. Figure 3 (b) is the spectrum (panoramic view), Figure 3 (c) in the equation is The nearby local amplification spectrum, Figure 3 (d) in the figure is a locally enlarged spectrum in the resonance region. The time domain diagram shows periodic pulses caused by local faults, and their intervals correspond to the rotation period of the passive wheel. The spectrum shows abundant modulation sidebands at the meshing frequency and resonance region. By locally enlarging the spectrum, modulation sidebands with intervals of the passive wheel rotation frequency can be observed, which preliminarily verifies the correctness of the vibration phenomenological model established.

[0097] To further verify the correctness of the invention, the model simulation signal is compared and analyzed with the experimental data. The vibration sensor is installed on the gearbox, with a sampling frequency of 25600 Hz and a sampling time of 3 seconds. Figure 4 The time domain vibration waveform and spectrum of the experimental data are shown, among which, Figure 4 (a) is the time domain waveform. Figure 4 (b) is the spectrum (panoramic view), Figure 4 (c) in the equation is The nearby local amplification spectrum, Figure 4 (d) in the figure is a locally enlarged spectrum in the resonance region. The experimental data also shows the pulse interval of the passive wheel rotation period, as well as the modulation sidebands at the meshing frequency and resonance region. The locally enlarged spectrum further confirms the consistency of the vibration characteristics of the model simulation signal and the measured signal in the time domain and frequency domain.

[0098] Although there are non-ideal components in the experimental signal, such as multi-stage meshing frequency components, manufacturing and installation errors, and interference from the rotation frequency of other components, in general, the simulation signal and the experimental signal show good consistency in both time domain waveform and frequency distribution characteristics, which verifies the effectiveness of the proposed modeling method. The phenomenological modeling method of the present invention comprehensively considers the modulation response and impulse response caused by local faults, and provides a comprehensive and reasonable analysis framework; compared with the traditional single modeling method, the present invention can more comprehensively reveal the generation mechanism of local fault vibration characteristics, provide a solid theoretical basis for the diagnosis of local faults, and show significant innovation. Based on the constructed model, local faults of different locations and degrees can be simulated and studied, the mapping relationship between the vibration signal characteristics and the fault state of the gear system can be clarified, the generation mechanism of fault characteristics can be revealed, and a clear a priori spectrum structure can be provided.

[0099] Embodiment 2:

[0100] like Figure 5 As shown, this implementation provides a gear local fault vibration phenomenological modeling system, including:

[0101] A fault interval calculation unit is configured to calculate the time interval between the start and end of the local fault according to the location and size of the local fault The specific working process of this unit is described in step S1.1 of Example 1, which will not be repeated here.

[0102] The modulation response simulation unit is configured to: use a window width of The rectangular window function is used to simulate the modulation response caused by the local fault; the specific working process of this unit is described in step S1.2 in Example 1, which will not be repeated here;

[0103] The impulse response simulation unit is configured as follows: using two intervals of The impulse function is used to simulate the impulse response caused by the local fault; the specific working process of this unit is described in step S1.3 in Example 1, which will not be repeated here;

[0104] The phenomenological modeling signal generating unit is configured to: use the sum of the modulation response and the impulse response as the total response of the system vibration signal caused by the local fault; the specific working process of this unit is described in step S1.4 in Example 1, which will not be repeated here.

[0105] It is understandable that the above-mentioned units can be separately or completely combined into one or several other units to constitute, or one (some) of the units can be further divided into multiple functionally smaller units to constitute, which can achieve the same operation without affecting the realization of the technical effects of the embodiments of the present application. The above-mentioned units are divided based on logical functions. In practical applications, the function of one unit can also be realized by multiple units, or the functions of multiple units can be realized by one unit. In other embodiments of the present application, the gear local fault vibration phenomenological modeling system can also include other units. In practical applications, these functions can also be implemented with the assistance of other units, and can be implemented by the collaboration of multiple units.

[0106] According to another embodiment of the present application, the system described in this embodiment can be constructed, and the gear local fault vibration phenomenological modeling method of the embodiment of the present application can be implemented by running a computer program (including program code) capable of executing the steps involved in the corresponding method described in Example 1 on a general computing device such as a computer including processing elements and storage elements such as a central processing unit (CPU), random access memory (RAM), and read-only memory (ROM). The computer program can be recorded on, for example, a computer-readable recording medium, and loaded into the above-mentioned computing device through the computer-readable recording medium, and run therein.

[0107] Embodiment 3:

[0108] like Figure 6 As shown, this implementation provides a method for diagnosing local faults of gears, including the following process:

[0109] S3.1: Based on the basic parameters of the gear system under test and the total response model of the system vibration signal established by the gear local fault vibration phenomenological modeling described in the first aspect of the present invention, local faults at different locations and different degrees are simulated to determine the mapping relationship between the vibration signal characteristics and the gear system fault state, and obtain the a priori spectrum structure;

[0110] S3.2: Based on the actual monitored gear system vibration information, the time domain waveform and spectrum structure of the measured signal are recorded. When periodic pulses appear in the time domain waveform of the measured signal, and the interval of the periodic pulses corresponds to the rotation period of the driven wheel, it is preliminarily determined that a local fault occurs;

[0111] S3.3: Compare the spectrum structure of the measured signal with the a priori spectrum structure. If the two are consistent or the difference is within a set range, it is ultimately determined that a local fault has occurred in the gear component of the gear system.

[0112] More specifically, step S3.1 of this implementation method specifically includes:

[0113] According to the basic parameters of the gear system under test (including key information such as the number of teeth and geometric dimensions), the vibration phenomenological model provided by the present invention is substituted, and the model is used to simulate local faults of different positions and degrees. Through model simulation, the mapping relationship between the vibration signal characteristics and the fault state of the gear system is clarified, thereby providing a clear and a priori spectrum structure.

[0114] In step S3.2 and step S3.3 of this implementation, specifically, the following steps are included:

[0115] The vibration information of the gear system is actually monitored, and the time domain waveform and spectrum structure of the measured signal are recorded. Taking the simulation signal and the measured signal in the above example as an example, when a local fault occurs in the passive gear, periodic pulses will appear in the time domain waveform of the vibration signal, and the intervals of these pulses correspond to the rotation period of the passive gear; in the spectrum, modulation sidebands with intervals of the passive gear rotation frequency will appear in the meshing frequency and resonance area. These vibration characteristics are completely consistent with the simulation signal based on the model or the difference is within the set range, so that the local fault of the passive gear can be accurately determined.

[0116] Embodiment 4:

[0117] like Figure 7 As shown, this implementation provides a gear local fault diagnosis system, including:

[0118] The a priori spectrum structure generating unit is configured to: simulate local faults at different positions and different degrees according to the basic parameters of the gear system under test and the total response model of the system vibration signal established by the gear local fault vibration phenomenological modeling described in the first aspect of the present invention, determine the mapping relationship between the vibration signal characteristics and the gear system fault state, and obtain the a priori spectrum structure; the specific working process of this unit is described in step S3.1 of embodiment 1, which will not be repeated here;

[0119] The local fault preliminary judgment unit is configured to: record the time domain waveform and spectrum structure of the measured signal according to the actual monitored gear system vibration information, and preliminarily judge that a local fault occurs when a periodic pulse appears in the time domain waveform of the measured signal, and the interval of the periodic pulse corresponds to the rotation period of the passive wheel; the specific working process of this unit is described in step S3.2 of embodiment 1, which will not be repeated here;

[0120] The local fault final judgment unit is configured to: compare the spectrum structure of the measured signal with the a priori spectrum structure. If the two are consistent or the difference is within a set range, it is finally judged that a local fault occurs in the gear component of the gear system; the specific working process of this unit is described in step S3.3 in Example 1, which will not be repeated here.

[0121] It is understandable that the above-mentioned units can be separately or completely combined into one or several other units to constitute, or one (some) of the units can be further divided into multiple functionally smaller units to constitute, which can achieve the same operation without affecting the realization of the technical effects of the embodiments of the present application. The above-mentioned units are divided based on logical functions. In practical applications, the function of one unit can also be realized by multiple units, or the functions of multiple units can be realized by one unit. In other embodiments of the present application, the gear local fault vibration phenomenological modeling system can also include other units. In practical applications, these functions can also be implemented with the assistance of other units, and can be implemented by the collaboration of multiple units.

[0122] According to another embodiment of the present application, the system described in this embodiment can be constructed, and the gear local fault vibration phenomenological modeling method of the embodiment of the present application can be implemented by running a computer program (including program code) capable of executing the steps involved in the corresponding method described in Example 1 on a general computing device such as a computer including processing elements and storage elements such as a central processing unit (CPU), random access memory (RAM), and read-only memory (ROM). The computer program can be recorded on, for example, a computer-readable recording medium, and loaded into the above-mentioned computing device through the computer-readable recording medium, and run therein.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A phenomenological modeling method for local gear fault vibration. It is characterized in that The process includes: Calculate the time interval between the start and end of a local fault based on the location and size of the local fault ; Using the window width The rectangular window function is used to simulate the modulation response caused by local faults; Use two intervals for The impulse function is used to simulate the impulse response caused by local faults; taking the sum of the modulation response and the impulse response as the total response of the system vibration signal caused by the local fault; Calculate the angle of gear rotation when the local fault begins to mesh and the angle of rotation of the gears when the meshing ends ; Local fault start time and fault end time They are: , , and Respectively represent the rotation frequency of the driving wheel and the passive wheel; The time interval between the start of the fault and the end of the fault for: ; The modulation response caused by a local fault is: ； in, (1, 2, ···, ) is the meshing vibration harmonic order, For the The amplitude of the harmonic of meshing vibration, For the The phase of the harmonics of the meshing vibration, is the meshing frequency, represents the pulse train caused by a local fault, t for the current moment; ； in, Indicates the pulse train number caused by local fault, I represents the total number of pulse trains caused by local faults, is the pulse amplitude, is the rotation period of the faulty gear, It is the moment when the first pulse caused by local fault enters meshing. The moment when the first pulse caused by a local fault ends the meshing, The local fault caused i The moment a pulse enters meshing, The local fault caused i The moment when a pulse ends the meshing; Impact response caused by local faults, including: ； in, represents the natural frequency of the faulty gear, represents the damping coefficient, and represents the impulse response amplitude caused by local faults, and the mod function is the remainder function. It is the moment when the first pulse caused by local fault enters meshing. The moment when the first pulse caused by a local fault ends the meshing, is the rotation period of the faulty gear.

2. A phenomenological modeling system for local gear fault vibration, It is characterized in that include: A fault interval calculation unit is configured to calculate the time interval between the start and end of the local fault according to the location and size of the local fault ; The modulation response simulation unit is configured to: use a window width of The rectangular window function is used to simulate the modulation response caused by local faults; The impulse response simulation unit is configured as follows: using two intervals of The impulse function is used to simulate the impulse response caused by local faults; A phenomenological modeling signal generating unit is configured to: use the sum of the modulation response and the impulse response as the total response of the system vibration signal caused by the local fault; In the modulation response simulation unit, the modulation response caused by a local fault is: ； in, (1, 2, ···, ) is the meshing vibration harmonic order, For the The amplitude of the harmonic of meshing vibration, For the The phase of the harmonics of the meshing vibration, is the meshing frequency, represents the pulse train caused by a local fault, t for the current moment; The impulse response caused by local faults in the impulse response simulation unit includes: ； in, represents the natural frequency of the faulty gear, represents the damping coefficient, and represents the impulse response amplitude caused by local faults, and the mod function is the remainder function. It is the moment when the first pulse caused by local fault enters meshing. The moment when the first pulse caused by a local fault ends the meshing, is the rotation period of the faulty gear.

3. A method for local fault diagnosis of gears, It is characterized in that The process includes: According to the basic parameters of the gear system under test and the total response model of the system vibration signal established by the gear local fault vibration phenomenological modeling method according to claim 1, local faults at different locations and different degrees are simulated to determine the mapping relationship between the vibration signal characteristics and the gear system fault state, and obtain the a priori spectrum structure; According to the actual monitored gear system vibration information, the time domain waveform and spectrum structure of the measured signal are recorded. When periodic pulses appear in the time domain waveform of the measured signal, and the interval of the periodic pulses corresponds to the rotation period of the passive wheel, it is preliminarily determined that a local fault has occurred. The spectrum structure of the measured signal is compared with the a priori spectrum structure. If the two are consistent or the difference is within the set range, it is ultimately determined that a local fault has occurred in the gear component of the gear system.

4. A gear local fault diagnosis system, It is characterized in that include: The a priori spectrum structure generating unit is configured to: simulate local faults at different positions and different degrees based on basic parameters of the gear system under test and a total response model of the system vibration signal established by the gear local fault vibration phenomenological modeling method according to claim 1, determine the mapping relationship between the vibration signal characteristics and the gear system fault state, and obtain the a priori spectrum structure; The local fault preliminary judgment unit is configured to: record the time domain waveform and spectrum structure of the measured signal according to the actually monitored gear system vibration information, and preliminarily judge that a local fault occurs when a periodic pulse appears in the time domain waveform of the measured signal, and the interval of the periodic pulse corresponds to the rotation period of the driven wheel; The local fault final judgment unit is configured to compare the spectrum structure of the measured signal with the a priori spectrum structure. If the two are consistent or the difference is within a set range, it is finally judged that a local fault occurs in the gear component of the gear system.

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