Abnormal gearbox operation status monitoring and alarm system based on sensor analysis

Abstract

The present invention relates to the field of data processing technology, and in particular to a gearbox operating state abnormality monitoring and alarm system based on sensor analysis, the system comprising a data acquisition module for acquiring a vibration signal of the gearbox, obtaining a time domain signal and constructing a time domain graph, converting the time domain signal into a frequency domain signal and constructing a spectrum graph; a data analysis module for obtaining a preliminary evaluation coefficient of the gearbox operating state according to the amplitude of each frequency in the spectrum graph and the number of peak points and valley points in the time domain graph; a feature acquisition module for obtaining a resonance-related feature index according to a spectrum width in the spectrum graph and a peak point in the time domain graph if the preliminary evaluation coefficient of the operating state is within a preset range; and an engine-related feature index according to the amplitude of the engine frequency in the spectrum graph; and an abnormal alarm module for performing an abnormal alarm on the gearbox according to the resonance-related feature index and the engine-related feature index, so as to improve the accuracy of the abnormal alarm on the gearbox operating state.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and in particular to a gearbox operating state abnormality monitoring and alarm system based on sensor analysis. Background Art

[0002] Failure of mechanical parts in the gearbox will seriously affect the operating state of the gearbox, thus causing driving safety problems. Avoiding major damage, ensuring driving safety, and providing accurate fault information to maintenance personnel are particularly important for gearbox status monitoring and fault diagnosis. Because vibration is the essential attribute of mechanical equipment during operation, obtaining gearbox vibration signals through vibration sensors for analysis and fault location is currently the lowest cost and most commonly used way to monitor the internal parts of the gearbox.

[0003] However, in actual monitoring, since the engine is tightly coupled to the gearbox through the transmission system, and the engine's output power is not uniform and stable, this will cause the unstable vibration to be transmitted to the gearbox through the transmission system, resulting in abnormal vibration signals. At the same time, the meshing process of the gear set inside the gearbox will arouse the resonance of other components (such as the housing), causing abnormal fluctuations in the gearbox vibration signal, and then issuing an error alarm.

[0004] Therefore, how to improve the accuracy of abnormal monitoring and alarm of the gearbox operating status has become an urgent problem to be solved. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a gearbox operating state abnormality monitoring and alarm system based on sensor analysis to solve the problem of how to improve the accuracy of abnormality monitoring and alarm on the gearbox operating state.

[0006] An embodiment of the present invention provides a gearbox operating state abnormality monitoring and alarm system based on sensor analysis, the system comprising the following steps:

[0007] A data acquisition module, used to collect a vibration signal of a gearbox of any automobile within a preset period of time, obtain a time domain signal, construct a time domain graph of the time domain signal, wherein the horizontal axis of the time domain graph represents time, and the vertical axis represents the amplitude of the vibration signal, convert the time domain signal into a frequency domain signal, and construct a spectrum graph of the frequency domain signal, wherein the horizontal axis of the spectrum graph represents frequency, and the vertical axis represents the amplitude of the vibration signal;

[0008] A data analysis module, used to obtain a preliminary evaluation coefficient of the operating state of the gearbox according to the amplitude of each frequency in the spectrum diagram and the number of peak points and valley points in the time domain diagram;

[0009] A feature acquisition module, for obtaining a resonance-related feature index of the vibration signal according to the spectrum width of the vibration signal in the spectrum diagram and the peak point in the time domain diagram if the operating state preliminary evaluation coefficient is within a preset abnormal operating state preliminary evaluation coefficient range; obtaining an engine frequency of any one of the vehicles in the preset time period, and obtaining an engine-related feature index of the vibration signal according to an amplitude corresponding to the engine frequency in the spectrum diagram;

[0010] The abnormal alarm module is used to issue an abnormal alarm for the operating state of the gearbox of any of the vehicles according to the resonance-related characteristic index and the engine-related characteristic index.

[0011] Furthermore, the data analysis module obtains a preliminary evaluation coefficient of the gearbox's operating state according to the amplitude of each frequency in the spectrum diagram and the number of peak points and valley points in the time domain diagram, including:

[0012] Obtaining a gear meshing frequency of the gearbox, obtaining an amplitude corresponding to the gear meshing frequency in the frequency spectrum, calculating the sum of the amplitudes of all frequencies in the frequency spectrum to obtain a total amplitude sum, calculating a ratio between the total amplitude and the amplitude corresponding to the gear meshing frequency, normalizing the ratio in inverse proportion, and obtaining a first operating state characteristic value of the gearbox;

[0013] In the time domain diagram, respectively obtaining the number of all peak points and the number of all valley points, normalizing the absolute value of the difference between the number of all peak points and the number of all valley points in inverse proportion, and obtaining a second operating state characteristic value of the gearbox;

[0014] An average value of the first operating state characteristic value and the second operating state characteristic value is calculated to obtain a preliminary evaluation coefficient of the operating state of the gearbox.

[0015] Furthermore, the feature acquisition module obtains the resonance-related feature index of the vibration signal according to the spectrum width of the vibration signal in the spectrum diagram and the peak point in the time domain diagram, including:

[0016] In the time domain diagram, the time interval between each two adjacent peak points is obtained, and the variance of all time intervals is calculated to obtain a periodic characteristic index of the vibration signal;

[0017] Obtaining the amplitudes of all peak points in the time domain graph, obtaining an amplitude mean, obtaining the amplitude of the maximum peak point in the time domain graph, calculating the ratio between the amplitude of the maximum peak point and the amplitude mean, and obtaining a signal volatility index of the vibration signal;

[0018] In the spectrum diagram, obtaining the spectrum width of the vibration signal, calculating the product between the spectrum width and the signal volatility index, and obtaining the frequency distribution characteristic value of the vibration signal;

[0019] The sum of the periodic characteristic index and the frequency distribution characteristic value is inversely normalized to obtain a resonance-related characteristic index of the vibration signal.

[0020] Furthermore, the feature acquisition module obtains the engine-related feature index of the vibration signal according to the amplitude corresponding to the engine frequency in the spectrum diagram, including:

[0021] Obtaining a frequency corresponding to a maximum amplitude in the frequency spectrum to obtain a maximum amplitude frequency, and calculating a ratio between the engine frequency and the maximum amplitude frequency to obtain a first variable;

[0022] In the frequency spectrum, the amplitude corresponding to the engine frequency, the amplitude corresponding to 2 times the engine frequency, and the amplitude corresponding to 3 times the engine frequency are obtained to obtain the fundamental wave amplitude, the second harmonic amplitude, and the third harmonic amplitude, respectively, and the fundamental wave amplitude, the second harmonic amplitude, and the third harmonic amplitude are accumulated to obtain a second variable;

[0023] The product of the first variable and the second variable is used as an independent variable of a hyperbolic tangent function to obtain an engine-related characteristic index of the vibration signal.

[0024] Furthermore, the abnormal alarm module performs an abnormal alarm on the operating state of the gearbox of any of the vehicles according to the resonance-related characteristic index and the engine-related characteristic index, including:

[0025] If the resonance-related characteristic index of the vibration signal is less than a preset resonance-related characteristic index threshold, and the engine-related characteristic index is less than a preset engine-related characteristic index threshold, an abnormal alarm is issued for the gearbox of any of the vehicles.

[0026] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0027] The present invention constructs a time domain diagram and a spectrum diagram according to the vibration signal of the gearbox, and monitors and analyzes the vibration signal of the gearbox in combination with the time domain and the frequency domain, so as to more comprehensively analyze the operating state of the gearbox. When the gearbox is in normal operation, its vibration signal is stable and regular, so according to the amplitude of each frequency in the spectrum diagram and the peak point and the valley point in the time domain diagram, the preliminary evaluation coefficient of the gearbox operating state is obtained, which is used to preliminarily evaluate the operating state of the gearbox. Considering that resonance and engine operation imbalance can also cause the vibration signal of the gearbox to be abnormal, but resonance and engine operation imbalance are not internal problems of the gearbox, when the gearbox is initially evaluated to be abnormal, it cannot be determined that the operating state of the gearbox is abnormal, and it is also necessary to analyze the vibration signal of the gearbox again according to the resonance characteristics and the engine operation imbalance characteristics, obtain the resonance-related characteristic index and the engine-related characteristic index, and perform an abnormal alarm on the operating state of the gearbox according to the resonance-related characteristic index and the engine-related characteristic index, eliminate the abnormal vibration signal of the gearbox caused by resonance and engine operation imbalance, and enhance the accuracy and reliability of abnormal monitoring and alarming of the operating state of the gearbox. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0029] Figure 1 It is a structural block diagram of a gearbox operating state abnormality monitoring and alarm system based on sensor analysis provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] Embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, but should not be understood as limiting the present disclosure.

[0031] It should be noted that the terms "first", "second", etc. in the specification of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure.

[0032] In order to illustrate the technical solution of the present invention, specific embodiments are provided below for illustration.

[0033] See also Figure 1 , is a structural block diagram of a gearbox operating state abnormality monitoring and alarm system based on sensor analysis provided in Embodiment 1 of the present invention, such as Figure 1 As shown, the system may include:

[0034] The data acquisition module 11 is used to collect the vibration signal of the gearbox of any automobile within a preset time period, obtain a time domain signal, construct a time domain graph of the time domain signal, wherein the horizontal axis of the time domain graph represents time and the vertical axis represents the amplitude of the vibration signal, convert the time domain signal into a frequency domain signal, and construct a spectrum graph of the frequency domain signal, wherein the horizontal axis of the spectrum graph represents frequency and the vertical axis represents the amplitude of the vibration signal.

[0035] The gearbox vibration sensor in any car is used to collect the gearbox vibration signal within 1 minute. There is no restriction here, and the implementer can set it according to the specific scenario. After obtaining the vibration signal, a high-pass filter is used to remove the ambient noise and high-frequency interference in the surrounding environment to obtain a time domain signal. The parameters of the high-pass filter are set as follows: cutoff frequency 50Hz, filter order 4, sampling frequency 1500Hz. There is no restriction here, and the implementer can set the filter parameters according to the specific scenario.

[0036] In order to avoid the limitations of a single domain and improve the robustness of abnormal monitoring of the gearbox's operating status, FFT (Fast Fourier Transform) is used to convert the time domain signal into a frequency domain signal, and the vibration signal of the gearbox is monitored and analyzed by combining the time domain and frequency domain, so as to capture the information in the vibration signal at different levels, more comprehensively describe the gearbox's operating status, and improve the accuracy of monitoring the gearbox's operating status. Among them, using FFT (Fast Fourier Transform) to convert the time domain signal into the frequency domain signal is an existing technology and will not be repeated here.

[0037] Furthermore, MATLAB is used to construct a time domain graph and a spectrum graph according to the time domain signal and the frequency domain signal, respectively, so as to facilitate the subsequent analysis of the operating status of the gearbox. The horizontal axis of the time domain graph represents time, and the vertical axis represents the amplitude of the vibration signal; the horizontal axis of the spectrum graph represents frequency, and the vertical axis represents the amplitude of the vibration signal. Drawing a time domain graph and a spectrum graph by MATLAB is a prior art and will not be described here.

[0038] The data analysis module 12 is used to obtain a preliminary evaluation coefficient of the operating state of the gearbox according to the amplitude of each frequency in the spectrum diagram and the number of peak points and valley points in the time domain diagram.

[0039] Since the gear meshing of the gearbox causes periodic impacts and generates vibrations, the gear meshing frequency is the most significant vibration signal frequency in the gearbox. Ideally, when the gearbox is in normal operation, the vibration generated by the gear meshing is smooth and regular, specifically: in the frequency domain, the gear meshing frequency should occupy a significant peak position and have a high amplitude; in the time domain, the positive half-cycle and negative half-cycle of the vibration signal should have similar amplitudes and shapes, that is, the number of peaks and valleys in the vibration signal are similar. When the gearbox is operating abnormally, its vibration signal no longer has these characteristics.

[0040] Since the main reasons that affect the vibration signal of the gearbox are failure of gears or other internal parts, resonance and unbalanced engine operation, and resonance and unbalanced engine operation do not point to the problem of failure of internal parts of the gearbox, it is necessary to make a preliminary judgment on the operation status of the gearbox. If the preliminary judgment shows that the operation status of the gearbox is abnormal, it is necessary to further determine whether the vibration signal abnormality is caused by resonance or unbalanced engine operation.

[0041] In the example of the present invention, the operating state of the gearbox is firstly determined based on the stable and regular characteristics of the vibration signal. The stability of the vibration signal is characterized by the proportion of the amplitude of the gear meshing frequency in the spectrum diagram in the amplitude of all frequencies: the larger the proportion, the smoother the vibration signal; the regularity of the vibration signal is characterized by the number of peak points and valley points in the time domain diagram: the closer the number of peak points and valley points, the more regular the vibration signal. Therefore, based on the proportion of the amplitude of the gear meshing frequency in the spectrum diagram in the amplitude of all frequencies, and the number of peak points and valley points in the time domain diagram, the preliminary evaluation coefficient of the operating state of the gearbox is obtained, which is used to preliminarily evaluate whether there is any abnormality in the operating state of the gearbox. The specific method of obtaining the preliminary evaluation coefficient of the operating state of the gearbox is as follows:

[0042] Obtaining a gear meshing frequency of the gearbox, obtaining an amplitude corresponding to the gear meshing frequency in the frequency spectrum, calculating the sum of the amplitudes of all frequencies in the frequency spectrum to obtain a total amplitude sum, calculating a ratio between the total amplitude and the amplitude corresponding to the gear meshing frequency, normalizing the ratio in inverse proportion, and obtaining a first operating state characteristic value of the gearbox;

[0043] In the time domain diagram, respectively obtaining the number of all peak points and the number of all valley points, normalizing the absolute value of the difference between the number of all peak points and the number of all valley points in inverse proportion, and obtaining a second operating state characteristic value of the gearbox;

[0044] An average value of the first operating state characteristic value and the second operating state characteristic value is calculated to obtain a preliminary evaluation coefficient of the operating state of the gearbox.

[0045] In one embodiment, the formula for calculating the gear meshing frequency of the gearbox is:

[0046]

[0047] in, represents the gear meshing frequency, Indicates the engine speed, Indicates the transmission ratio (each gear in the car has a specific transmission ratio), Indicates the number of teeth on the gear.

[0048] It should be noted that the acquisition of gear meshing frequency is a prior art and will not be described in detail here.

[0049] Furthermore, according to the amplitude corresponding to the frequency that is the same as the gear meshing frequency in the spectrum diagram and the number of peak points and valley points in the time domain diagram, the preliminary evaluation coefficient of the gearbox operation state is obtained. The calculation formula of the preliminary evaluation coefficient of the operation state is:

[0050]

[0051] in, Indicates the preliminary evaluation coefficient of the gearbox's operating status, represents an exponential function with the natural constant e as the base, which is used for inverse normalization. n represents the number of all frequencies in the spectrum graph. represents the amplitude of the i-th frequency in the spectrum graph, Indicates the amplitude corresponding to the frequency in the spectrum diagram that is the same as the gear meshing frequency, Represents the number of all peak points in the time domain graph, Represents the number of all valley points in the time domain graph, Represents the absolute value symbol.

[0052] It should be noted that is the total amplitude and, That is the first operating state characteristic value of the gearbox, The smaller the value of is, the smaller the proportion of the amplitude of the gear meshing frequency in the frequency domain diagram is, and the worse the stability of the vibration signal is. The larger the value of is, the smaller the characteristic value of the first operating state of the gearbox is. The smaller the value, the less likely the gearbox is in normal operation, that is, the greater the possibility that the gearbox is in abnormal operation; That is the second operating state characteristic value of the gearbox, The larger the value of is, the smaller the similarity between the number of peak values ​​and the number of valley values ​​in the vibration signal is, and thus the smaller the characteristic value of the second operating state of the gearbox is. The smaller the value, the less likely the gearbox is in normal operation, that is, the greater the possibility that the gearbox is in abnormal operation.

[0053] The feature acquisition module 13 is used to obtain the resonance-related feature index of the vibration signal according to the spectrum width of the vibration signal in the spectrum diagram and the peak point in the time domain diagram if the preliminary evaluation coefficient of the operating state is within the preset preliminary evaluation coefficient range of the abnormal operating state; obtain the engine frequency of any one of the vehicles in the preset time period, and obtain the engine-related feature index of the vibration signal according to the amplitude corresponding to the engine frequency in the spectrum diagram.

[0054] The meshing process of the gear set inside the gearbox will arouse the resonance of other components (such as the box), resulting in abnormal fluctuations in the vibration signal of the gearbox. At the same time, the engine is tightly coupled with the gearbox through the transmission system, and the output power of the engine is not uniform and stable, which will cause this unstable vibration to be transmitted to the gearbox through the transmission system, making the vibration signal of the gearbox abnormal. Therefore, if it is determined that the vibration signal of the gearbox is abnormal, it is necessary to analyze the vibration signal again.

[0055] Set the preset abnormal operation status preliminary assessment coefficient range to , there is no restriction here, the implementer can set it according to the specific scenario. If the gearbox operation status preliminary evaluation coefficient , it means that the gearbox is in normal operation and no alarm is given; if , it means that the vibration signal of the gearbox is abnormal, but it may be caused by external influences such as resonance or unbalanced engine operation. Therefore, it is necessary to further analyze the vibration signal of the gearbox to eliminate the interference of external influences such as resonance or unbalanced engine operation, and enhance the reliability of abnormal monitoring and alarm of the gearbox operation status.

[0056] Regarding the resonance phenomenon, the frequency distribution of the vibration signal caused by part failure is wider than that caused by resonance, and it is also sudden and intermittent, and has a shorter duration. Therefore, in the vibration signal of the gearbox, the spectrum width of the vibration signal caused by resonance is narrower than that caused by part failure. According to the principle of time-frequency uncertainty, there is a complementary relationship between the time persistence and spectrum width of the signal, that is, the narrower the bandwidth, the longer the duration of the signal. At the same time, the narrower the bandwidth, the signal is dominated by the frequency component. Therefore, the smaller the spectrum width, the more frequency components dominated by resonance in the vibration signal, that is, the abnormality of the vibration signal of the gearbox is more likely to be caused by resonance.

[0057] At the same time, in the resonant state, the mechanical system will also be affected by damping, which will gradually stabilize the vibration. Therefore, the signal change caused by resonance is more stable than that caused by part failure, that is, the signal volatility caused by resonance is smaller than that caused by part failure, which is specifically manifested in the smaller difference between the mean of the amplitude of all peak points in the time domain graph and the amplitude of the maximum peak point. In addition, the vibration signal caused by resonance usually has a certain periodicity. Periodic signals usually have repeated peaks in the time domain, and the time interval between each adjacent peak point is relatively fixed.

[0058] Therefore, according to the spectrum width of the vibration signal in the spectrum diagram and the peak point in the time domain diagram, the resonance-related characteristic index of the vibration signal is obtained. The specific acquisition method is:

[0059] In the time domain diagram, the time interval between each two adjacent peak points is obtained, and the variance of all time intervals is calculated to obtain a periodic characteristic index of the vibration signal;

[0060] Obtaining the amplitudes of all peak points in the time domain graph, obtaining an amplitude mean, obtaining the amplitude of the maximum peak point in the time domain graph, calculating the ratio between the amplitude of the maximum peak point and the amplitude mean, and obtaining a signal volatility index of the vibration signal;

[0061] In the spectrum diagram, obtaining the spectrum width of the vibration signal, calculating the product between the spectrum width and the signal volatility index, and obtaining the frequency distribution characteristic value of the vibration signal;

[0062] The sum of the periodic characteristic index and the frequency distribution characteristic value is inversely normalized to obtain a resonance-related characteristic index of the vibration signal.

[0063] In one embodiment, the calculation formula of the spectrum width of the vibration signal in the spectrum diagram is:

[0064]

[0065] in, represents the spectrum width, Indicates the frequency of the dB point to the right of the maximum value in the spectrum graph. Indicates the frequency of the dB point to the left of the maximum value in the spectrum graph.

[0066] It should be noted that the dB point refers to the point corresponding to the drop to 0.707 times of the maximum amplitude in the spectrum diagram. The acquisition of the spectrum width is a prior art and will not be described in detail here.

[0067] Furthermore, according to the spectrum width and the peak point in the time domain diagram, the resonance-related characteristic index of the vibration signal is obtained, and the calculation formula of the resonance-related characteristic index is:

[0068]

[0069] Among them, Q represents the resonance-related characteristic index of the vibration signal, represents the spectrum width of the vibration signal in the spectrum diagram, Represents the number of all peak points in the time domain graph, represents the amplitude of the jth peak point in the time domain graph, Represents the amplitude of the maximum peak point in the time domain graph, Indicator representing the periodic characteristics of the vibration signal. Represents an exponential function with the natural constant e as base, used for inverse normalization.

[0070] It should be noted that It is the signal volatility index of the vibration signal. That is the frequency distribution characteristic value of the vibration signal, The smaller the value is, the more components in the vibration signal whose main frequency is dominated by resonance. Therefore, the smaller the frequency distribution characteristic value of the vibration signal is, and the larger the value of Q is, the more likely the abnormal change of the vibration signal of the gearbox is caused by resonance. That is, it is the mean of the amplitudes of all peak points in the time domain diagram (amplitude mean). The larger the amplitude mean, the closer the amplitude mean is to the amplitude of the maximum peak point in the time domain diagram, the smoother the vibration signal of the gearbox changes, and the smaller the signal volatility index, the larger the Q value, which means that the abnormal change of the vibration signal of the gearbox is more likely to be caused by resonance. The smaller the value is, the more fixed the time interval between two adjacent peak points in the time domain is, the more periodic the vibration signal of the gearbox is, and the larger the value of Q is, the more likely the abnormal change of the vibration signal of the gearbox is caused by resonance.

[0071] Regarding the phenomenon of unbalanced engine operation, since the engine speed will directly affect the vibration frequency of the gearbox, if the unbalanced engine operation causes abnormal changes in the vibration signal of the gearbox, the engine frequency will appear near the main peak frequency (the frequency corresponding to the maximum amplitude) in the spectrum graph, and the 2nd and 3rd times harmonics of the engine frequency will occupy the position of the secondary peak in the spectrum graph.

[0072] Therefore, the engine frequency is first obtained, wherein the acquisition of the engine frequency is a prior art and will not be described in detail here. Then, according to the amplitude corresponding to the frequency that is the same as the engine frequency in the spectrum diagram, the engine-related characteristic index of the vibration signal is obtained, and the specific acquisition method is as follows:

[0073] Obtaining a frequency corresponding to a maximum amplitude in the frequency spectrum to obtain a maximum amplitude frequency, and calculating a ratio between the engine frequency and the maximum amplitude frequency to obtain a first variable;

[0074] In the frequency spectrum, the amplitude corresponding to the engine frequency, the amplitude corresponding to 2 times the engine frequency, and the amplitude corresponding to 3 times the engine frequency are obtained to obtain the fundamental wave amplitude, the second harmonic amplitude, and the third harmonic amplitude, respectively, and the fundamental wave amplitude, the second harmonic amplitude, and the third harmonic amplitude are accumulated to obtain a second variable;

[0075] The product of the first variable and the second variable is used as an independent variable of a hyperbolic tangent function to obtain an engine-related characteristic index of the vibration signal.

[0076] In one embodiment, the calculation formula of the engine-related characteristic index of the vibration signal is:

[0077]

[0078] Where P represents the engine-related characteristic index of the vibration signal, Indicates the engine frequency, Indicates the frequency corresponding to the maximum amplitude in the spectrum (main peak frequency), Indicates the amplitude (fundamental amplitude) corresponding to the frequency that is the same as the engine frequency in the spectrum diagram. Indicates the amplitude corresponding to the frequency that is twice the engine frequency in the spectrum (second harmonic amplitude), Indicates the amplitude corresponding to the frequency that is three times the engine frequency in the spectrum (third harmonic amplitude), represents the hyperbolic tangent function.

[0079] It should be noted that To limit the output to . The larger the value of is, the closer the engine frequency is to the main peak frequency in the spectrum graph, and the larger the value of P is, the more likely it is that the abnormal change in the vibration signal of the gearbox is caused by unbalanced engine operation. The larger the value of , the greater the proportion of the engine frequency and its 2- and 3-fold harmonic frequencies in the vibration signal of the gearbox. Therefore, the larger the value of P, the more likely it is that the abnormal change in the vibration signal of the gearbox is caused by unbalanced engine operation.

[0080] At this point, the resonance-related characteristic index and the engine-related characteristic index of the vibration signal of the gearbox are obtained.

[0081] The abnormal alarm module 14 is used to issue an abnormal alarm for the operating state of the gearbox of any of the vehicles according to the resonance-related characteristic index and the engine-related characteristic index.

[0082] When the preliminary evaluation coefficient of the gearbox operation status obtained in the data analysis module 12 When the gearbox is abnormal, it is considered that the gearbox may be abnormal. In order to eliminate the abnormality of the gearbox vibration signal caused by resonance and unbalanced engine operation, the vibration signal of the gearbox is further analyzed in the feature acquisition module 13 to obtain the resonance-related characteristic index and the engine-related characteristic index of the vibration signal. Further, the gearbox operation state is alarmed according to the resonance-related characteristic index and the engine-related characteristic index.

[0083] The preset resonance-related characteristic index threshold is set to 0.7, and the preset engine-related characteristic index threshold is set to 0.7. There is no restriction here, and the implementer can set it according to the specific scenario.

[0084] If the resonance-related characteristic index Q is greater than or equal to 0.7, or the engine-related characteristic index P is greater than or equal to 0.7, it means that the abnormal vibration signal of the gearbox is not caused by the failure of the internal parts of the gearbox. At this time, the gearbox is in normal operation, so no alarm is given. Among them, if the resonance-related characteristic index Q is greater than or equal to 0.7, it means that the abnormal vibration signal of the gearbox is caused by resonance; if the engine-related characteristic index P is greater than or equal to 0.7, it means that the abnormal vibration signal of the gearbox is caused by unbalanced engine operation.

[0085] If the resonance-related characteristic index Q is less than 0.7, and the engine-related characteristic index P is less than 0.7, it means that the abnormal vibration signal of the gearbox is caused by the failure of internal parts of the gearbox. At this time, the operating state of the gearbox is abnormal, and an abnormal alarm is required to notify relevant personnel in time.

[0086] In summary, the present invention provides a gearbox operating state abnormality monitoring and alarm system based on sensor analysis, including a data acquisition module, which is used to collect vibration signals of a gearbox of any automobile within a preset time period, obtain a time domain signal, construct a time domain graph of the time domain signal, wherein the horizontal axis of the time domain graph represents time, and the vertical axis represents the amplitude of the vibration signal, convert the time domain signal into a frequency domain signal, and construct a spectrum graph of the frequency domain signal, wherein the horizontal axis of the spectrum graph represents frequency, and the vertical axis represents the amplitude of the vibration signal; a data analysis module, which is used to obtain the gearbox according to the amplitude of each frequency in the spectrum graph and the number of peak points and valley points in the time domain graph. The preliminary evaluation coefficient of the running state of the gearbox; a feature acquisition module, which is used to obtain the resonance-related characteristic index of the vibration signal according to the spectrum width of the vibration signal in the spectrum diagram and the peak point in the time domain diagram if the preliminary evaluation coefficient of the running state is within the preset abnormal running state preliminary evaluation coefficient range; obtain the engine frequency of any of the vehicles in the preset time period, and obtain the engine-related characteristic index of the vibration signal according to the amplitude corresponding to the engine frequency in the spectrum diagram; an abnormal alarm module, which is used to make an abnormal alarm for the running state of the gearbox of any of the vehicles according to the resonance-related characteristic index and the engine-related characteristic index. Among them, the time domain diagram and the spectrum diagram are constructed according to the vibration signal of the gearbox, and the vibration signal of the gearbox is monitored and analyzed in combination with the time domain and the frequency domain to more comprehensively analyze the running state of the gearbox. When the gearbox is in normal running state, its vibration signal is stable and regular, so according to the amplitude of each frequency in the spectrum diagram and the peak point and valley point in the time domain diagram, the preliminary evaluation coefficient of the running state of the gearbox is obtained for preliminary evaluation of the running state of the gearbox. Taking into account that resonance and unbalanced engine operation will also cause abnormal vibration signals of the gearbox, but resonance and unbalanced engine operation are not internal problems of the gearbox, so when the gearbox is initially assessed to be abnormal, it cannot be concluded that the operating state of the gearbox is abnormal. It is also necessary to analyze the vibration signals of the gearbox again based on the resonance characteristics and the unbalanced engine operation characteristics, and obtain resonance-related characteristic indicators and engine-related characteristic indicators, and then issue an abnormal alarm for the operating state of the gearbox based on the resonance-related characteristic indicators and the engine-related characteristic indicators, eliminate the abnormal vibration signals of the gearbox caused by resonance and unbalanced engine operation, and enhance the accuracy and reliability of abnormal monitoring and alarm of the operating state of the gearbox.

[0087] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A gearbox operating status abnormality monitoring and alarm system based on sensor analysis, characterized in that: The gearbox operating state abnormality monitoring and alarm system based on sensor analysis includes: A data acquisition module, used to collect a vibration signal of a gearbox of any automobile within a preset period of time, obtain a time domain signal, construct a time domain graph of the time domain signal, wherein the horizontal axis of the time domain graph represents time, and the vertical axis represents the amplitude of the vibration signal, convert the time domain signal into a frequency domain signal, and construct a spectrum graph of the frequency domain signal, wherein the horizontal axis of the spectrum graph represents frequency, and the vertical axis represents the amplitude of the vibration signal; A data analysis module, used to obtain a preliminary evaluation coefficient of the operating state of the gearbox according to the amplitude of each frequency in the spectrum diagram and the number of peak points and valley points in the time domain diagram; A feature acquisition module, for obtaining a resonance-related feature index of the vibration signal according to the spectrum width of the vibration signal in the spectrum diagram and the peak point in the time domain diagram if the operating state preliminary evaluation coefficient is within a preset abnormal operating state preliminary evaluation coefficient range; obtaining an engine frequency of any one of the vehicles in the preset time period, and obtaining an engine-related feature index of the vibration signal according to an amplitude corresponding to the engine frequency in the spectrum diagram; An abnormal alarm module, used for issuing an abnormal alarm for the operating state of the gearbox of any of the vehicles according to the resonance-related characteristic index and the engine-related characteristic index; The data analysis module obtains a preliminary evaluation coefficient of the gearbox's operating state according to the amplitude of each frequency in the spectrum diagram and the number of peak points and valley points in the time domain diagram, including: Obtaining a gear meshing frequency of the gearbox, obtaining an amplitude corresponding to the gear meshing frequency in the frequency spectrum, calculating the sum of the amplitudes of all frequencies in the frequency spectrum to obtain a total amplitude sum, calculating a ratio between the total amplitude and the amplitude corresponding to the gear meshing frequency, normalizing the ratio in inverse proportion, and obtaining a first operating state characteristic value of the gearbox; In the time domain diagram, respectively obtaining the number of all peak points and the number of all valley points, normalizing the absolute value of the difference between the number of all peak points and the number of all valley points in inverse proportion, and obtaining a second operating state characteristic value of the gearbox; Calculating an average value of the first operating state characteristic value and the second operating state characteristic value to obtain a preliminary evaluation coefficient of the operating state of the gearbox; The feature acquisition module obtains the resonance-related feature index of the vibration signal according to the spectrum width of the vibration signal in the spectrum diagram and the peak point in the time domain diagram, including: In the time domain diagram, the time interval between each two adjacent peak points is obtained, and the variance of all time intervals is calculated to obtain a periodic characteristic index of the vibration signal; Obtaining the amplitudes of all peak points in the time domain graph, obtaining an amplitude mean, obtaining the amplitude of the maximum peak point in the time domain graph, calculating the ratio between the amplitude of the maximum peak point and the amplitude mean, and obtaining a signal volatility index of the vibration signal; In the spectrum diagram, obtaining the spectrum width of the vibration signal, calculating the product between the spectrum width and the signal volatility index, and obtaining the frequency distribution characteristic value of the vibration signal; Normalizing the sum of the periodic characteristic index and the frequency distribution characteristic value in inverse proportion to obtain a resonance-related characteristic index of the vibration signal; The feature acquisition module obtains the engine-related feature index of the vibration signal according to the amplitude corresponding to the engine frequency in the spectrum diagram, including: Obtaining a frequency corresponding to a maximum amplitude in the frequency spectrum to obtain a maximum amplitude frequency, and calculating a ratio between the engine frequency and the maximum amplitude frequency to obtain a first variable; In the frequency spectrum, the amplitude corresponding to the engine frequency, the amplitude corresponding to 2 times the engine frequency, and the amplitude corresponding to 3 times the engine frequency are obtained to obtain the fundamental wave amplitude, the second harmonic amplitude, and the third harmonic amplitude, respectively, and the fundamental wave amplitude, the second harmonic amplitude, and the third harmonic amplitude are accumulated to obtain a second variable; The product of the first variable and the second variable is used as an independent variable of a hyperbolic tangent function to obtain an engine-related characteristic index of the vibration signal.

2. The gearbox operating state abnormality monitoring and alarm system based on sensor analysis according to claim 1 is characterized in that: The abnormal alarm module performs an abnormal alarm on the operating state of the gearbox of any of the vehicles according to the resonance-related characteristic index and the engine-related characteristic index, including: If the resonance-related characteristic index of the vibration signal is less than a preset resonance-related characteristic index threshold, and the engine-related characteristic index is less than a preset engine-related characteristic index threshold, an abnormal alarm is issued for the gearbox of any of the vehicles.

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