A Comprehensive Method and System for Detecting Abnormalities in Transmission Gear Supports Based on Vibration Signal Demodulation

Abstract

This invention belongs to the field of fault detection technology for integrated transmission systems of tracked vehicles, specifically relating to a method and system for detecting abnormal support of integrated transmission gears using vibration signal demodulation. The method and detection system are implemented by means of a vibration sensor, a multi-channel data acquisition device, a computer, and a data analysis module installed on the computer. This invention addresses the problem of severe faults caused by abnormal support conditions in typical gear support configurations of integrated transmission systems. It proposes a multi-harmonic optimal demodulation method and a rotational impact measurement criterion to effectively detect abnormal gear support conditions. Furthermore, it considers the frequency shift and amplitude distortion caused by inherent transmission errors in the integrated transmission system, eliminating amplitude distortion through multi-harmonic optimal demodulation, and overcoming the influence of frequency shift by setting order tolerances and employing a special normalization strategy.

Description

Technical Field

[0001] This invention belongs to the field of fault detection technology for integrated transmission devices of tracked vehicles, specifically relating to a method and system for detecting abnormalities in integrated transmission gear support by vibration signal demodulation. Background Technology

[0002] The integrated transmission system is a complex electromechanical-hydraulic coupled transmission system that enables integrated control of steering, gear shifting, and speed change, and is one of the core components of tracked vehicles. Due to its highly integrated structure and tightly interconnected components, a failure in any part can lead to the failure of the entire system, thus affecting the mobility and reliability of the tracked vehicle. According to incomplete statistics, gear failure rates in rotating machinery are as high as 60%, making gear detection crucial for preventing accidents.

[0003] Currently, there are three main types of technologies in the field of gear fault detection in rotating machinery. The first type uses empirical mode decomposition (EMD) to decompose the vibration signal of the equipment into several intrinsic mode components (IMCs), and then uses the reconstructed signal from these IMCs for detection. The second type uses sparse decomposition to match the vibration signal of the equipment with a parameterized dictionary, and then extracts the impact characteristics from the signal based on matching pursuit or statistical indicators to detect the health status of the gears. The third type designs different neural network architectures for different gear fault detection problems and trains them to obtain classifiers applicable to various operating conditions, thus transforming the gear fault detection problem into a binary or multi-class classification problem in machine learning. All of these technologies ultimately rely on the amplitude at the gear meshing frequency, or the ratio of the modulation sideband amplitude to the meshing frequency amplitude.

[0004] Many integrated transmission systems employ a unique structure where the support shaft is fixed and the gears rotate with the outer ring of the support bearing. The gears are connected to the shaft via bearings whose outer rings rotate only, and both ends of the shaft are completely fixed and cannot rotate. This support type is common in major components of integrated transmission systems, such as the front drive, fan drive, and pump auxiliary drive, primarily used for power transmission and distribution. Due to the high power density and high-speed, heavy-load characteristics of armored equipment integrated transmission systems, the system experiences significant deformation. Furthermore, its highly integrated and shared internal structure makes measurement and inspection difficult, resulting in small sample sizes, poor machining and assembly stability, and significant susceptibility to accumulated manufacturing errors. This makes it highly susceptible to inherent support abnormalities at the manufacturing stage, which can further lead to service-stage failures, severely impacting equipment reliability and service life. Due to the structural uniqueness, these gear support abnormalities are not reflected in the vibration signal meshing frequency and its modulation sideband, rendering classic rotating machinery gear fault detection techniques ineffective and failing to meet practical engineering requirements.

[0005] There are currently no patents specifically for fault detection of gears in integrated transmission devices, but there are patents for fault detection of helicopter planetary gears, wind turbine gears, etc., such as "Metametric Learning-Driven Fault Diagnosis Method for Helicopter Planetary Gearbox". Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] The technical problem to be solved by the present invention is how to overcome the above-mentioned problems of the prior art and provide a method and system for detecting abnormal gear support status of integrated transmission devices.

[0008] (II) Technical Solution

[0009] To solve the above technical problems, the present invention provides a vibration signal demodulation integrated transmission gear support anomaly detection system, the system being used to detect anomalies in the support state of gears in an integrated transmission device;

[0010] The system includes: a vibration sensor, a multi-channel data acquisition device, a computer, and a data analysis module installed on the computer;

[0011] The vibration sensor is connected to a multi-channel data acquisition device to convert the vibration characteristics of the integrated transmission device into an electrical signal input.

[0012] The multi-channel data acquisition device is used to convert electrical signals into digital signals and input them into a connected computer.

[0013] The data analysis module installed on the computer is used to detect abnormalities in the gear support status of the integrated transmission device, analyze digital signals, and provide detection results on whether the gear has malfunctioned.

[0014] The vibration sensor is used to detect vibrations when the integrated transmission is operating in a specific gear and under loading conditions, at an engine speed of f. s At that time, vibration signals were collected for no less than 10 seconds.

[0015] The multi-channel data acquisition device is used to convert the vibration signal into a digital signal and input it into a connected computer.

[0016] The data analysis module installed on the computer is used to detect abnormalities in the gear support status of the integrated transmission device, analyze digital signals, and provide detection results on whether the gear has failed.

[0017] The specific testing process includes:

[0018] Step 1: Perform preprocessing on the vibration signal in digital form, including removing the mean and trend term, to obtain the discrete vibration signal s(t). i), i = 1, 2, ..., N, where t i This represents N sampling times, and then the engine speed f is calculated based on the transmission ratio of the integrated transmission system under the condition of no transmission error. s The corresponding gear frequency f ms ;

[0019] Step 2: Considering that the gear frequency f is fluctuating or changing when the engine speed is in a state of flux or variation. ms The corresponding signal components are represented by a class of amplitude-frequency modulation (AM-FM) signal models:

[0020]

[0021] Where j is the imaginary unit, θ0 is the initial phase, and a(t) represents the instantaneous amplitude;

[0022] Define frequency demodulation operator and the corresponding frequency modulation operator Among them, f d (t) > 0 is called the demodulation frequency, f c (t)>0 is related to f ms The corresponding carrier wave is used to multiply the signal by the demodulation operator to obtain the demodulated signal:

[0023]

[0024] a d (t) represents the instantaneous amplitude of the demodulated signal;

[0025] When the demodulation frequency equals the instantaneous gear rotation frequency, i.e., f d (t)=f ms (t), the signal is demodulated as:

[0026]

[0027] At this point, the frequency modulation term in the demodulated signal phase is eliminated, and the signal becomes a frequency modulation term concentrated on the carrier f. c For pure amplitude-modulated signals near (t), the bandwidth reaches its minimum.

[0028] To estimate the optimal demodulation frequency, the smoothness of the signal is evaluated using the energy of the second derivative of the demodulated signal, which reflects the signal's bandwidth. Specifically, the following optimization problem is solved:

[0029]

[0030] Where i = 1, 2, ..., K represents the gear rotation frequency f under consideration. ms The higher harmonic order, a” id (t) represents a idThe second difference of (t) is given, where ||·||² is the 2-norm; the optimal demodulation frequency is obtained by solving the above optimization problem using the Lagrange multiplier method or other optimization methods.

[0031] Step 3: [Regarding...] Numerical integration yields the angle rotated by the gear in the angular domain of the integrated transmission device. Through the Equal-interval resampling yields the resampled vibration signal s. o (t i If i = 1, 2, ..., N, then in s o (t i In this process, the distortion of gear frequency amplitude caused by fluctuations or changes in engine speed is effectively eliminated; the engine frequency f s Defined as first order, for the resampled signal s o (t i Order tracking is performed on i = 1, 2, ..., N to obtain the order spectrum S. o (f k In the solved order spectrum, the meshing order of the gear is equal to the number of teeth on the gear. in accordance with The order components near the order can be used, combined with existing modulation sideband amplitude techniques, to determine whether there is a gear pair fault.

[0032] Step 4: Considering transmission error factors, set the order tolerance range [Ω]. min ,Ω max The amplitudes of the order components within the tolerance range of the gear frequency and its higher harmonics are normalized. For the higher harmonics of the frequency, the amplitude is also divided by the maximum amplitude within the tolerance range of the gear frequency fundamental frequency, i.e.:

[0033]

[0034] In the formula, the subscript [K] indicates the order tolerance range of the Kth harmonic component of the gear frequency;

[0035] Step 5: Define the gear frequency f ms Rotational impact measurement I m (f ms )as follows:

[0036]

[0037] Similarly, the rotational impact measure I of the engine input frequency can be calculated. m (f s ), if I m (f ms )>I m (fs If the gear is unbalanced, it indicates a gear imbalance fault; otherwise, it indicates that the gear is in good condition.

[0038] In step 5, the rotating impact measurement I m (f ms ) and I m (f s The larger the ratio of ), the more serious the gear imbalance fault.

[0039] In general, if I m (f ms ) / I m (f s If the value is greater than 2, it indicates that the gear imbalance is quite serious.

[0040] Furthermore, this invention provides a comprehensive transmission gear support anomaly detection method based on vibration signal demodulation, which is implemented using the aforementioned comprehensive transmission gear support anomaly detection system based on vibration signal demodulation. The method includes the following steps:

[0041] Step 0: Operate the integrated transmission device in a specific gear and under loading conditions, with the engine speed at f. s At that time, a vibration sensor should be used to collect vibration signals for no less than 10 seconds;

[0042] Step 1: Perform preprocessing on the vibration signal in digital form, including removing the mean and trend term, to obtain the discrete vibration signal s(t). i ), i = 1, 2, ..., N, where t i This represents N sampling times, and then the engine speed f is calculated based on the transmission ratio of the integrated transmission system under the condition of no transmission error. s The corresponding gear frequency f ms ;

[0043] Step 2: Considering that the gear frequency f is fluctuating or changing when the engine speed is in a state of flux or variation. ms The corresponding signal components are represented by a class of amplitude-frequency modulation (AM-FM) signal models:

[0044]

[0045] Where j is the imaginary unit, θ0 is the initial phase, and a(t) represents the instantaneous amplitude;

[0046] Define frequency demodulation operator and the corresponding frequency modulation operator Among them, f d (t) > 0 is called the demodulation frequency, f c (t)>0 is related to f msThe corresponding carrier wave is used to multiply the signal by the demodulation operator to obtain the demodulated signal:

[0047]

[0048] a d (t) represents the instantaneous amplitude of the demodulated signal;

[0049] When the demodulation frequency equals the instantaneous gear rotation frequency, i.e., f d (t)=f ms (t), the signal is demodulated as:

[0050]

[0051] At this point, the frequency modulation term in the demodulated signal phase is eliminated, and the signal becomes a frequency modulation term concentrated on the carrier f. c For pure amplitude-modulated signals near (t), the bandwidth reaches its minimum.

[0052] To estimate the optimal demodulation frequency, the smoothness of the signal is evaluated using the energy of the second derivative of the demodulated signal, which reflects the signal's bandwidth. Specifically, the following optimization problem is solved:

[0053]

[0054] Where i = 1, 2, ..., K represents the gear rotation frequency f under consideration. ms The higher harmonic order, a” id (t) represents a id The second difference of (t) is given, where ||·||² is the 2-norm; the optimal demodulation frequency is obtained by solving the above optimization problem using the Lagrange multiplier method or other optimization methods.

[0055] Step 3: [Regarding...] Numerical integration yields the angle rotated by the gear in the angular domain of the integrated transmission device. Through the Equal-interval resampling yields the resampled vibration signal s. o (t i If i = 1, 2, ..., N, then in s o (t i In this process, the distortion of gear frequency amplitude caused by fluctuations or changes in engine speed is effectively eliminated; the engine frequency f s Defined as first order, for the resampled signal s o (t i Order tracking is performed on i = 1, 2, ..., N to obtain the order spectrum S. o (f k In the solved order spectrum, the meshing order of the gear is equal to the number of teeth on the gear. in accordance with The order components near the order can be used, combined with existing modulation sideband amplitude techniques, to determine whether there is a gear pair fault.

[0056] Step 4: Considering transmission error factors, set the order tolerance range [Ω]. min ,Ω max The amplitudes of the order components within the tolerance range of the gear frequency and its higher harmonics are normalized. For the higher harmonics of the frequency, the amplitude is also divided by the maximum amplitude within the tolerance range of the gear frequency fundamental frequency, i.e.:

[0057]

[0058] In the formula, the subscript [K] indicates the order tolerance range of the Kth harmonic component of the gear frequency;

[0059] Step 5: Define the gear frequency f ms Rotational impact measurement I m (f ms )as follows:

[0060]

[0061] Similarly, the rotational impact measure I of the engine input frequency can be calculated. m (f s ), if I m (f ms )>I m (f s If the gear is unbalanced, it indicates a gear imbalance fault; otherwise, it indicates that the gear is in good condition.

[0062] In step 5, the rotating impact measurement I m (f ms ) and I m (f s The larger the ratio of ), the more serious the gear imbalance fault.

[0063] In general, if I m (f ms ) / I m (f s If the value is greater than 2, it indicates that the gear imbalance is quite serious.

[0064] (III) Beneficial Effects

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] (1) This invention proposes a special detection method and judgment criteria for abnormal gear support condition faults. Specifically, based on the proposed multi-harmonic optimal demodulation method and rotational impact measurement criterion, it can effectively realize the detection of abnormal gear support condition faults, which is a good supplement to the existing technology that can only realize the detection of common fault types such as pitting, wear and tooth breakage of typical gears.

[0067] (2) The present invention takes into account the transmission error introduced by the inherent complex transmission relationship of the integrated transmission device structure, eliminates amplitude distortion by multi-harmonic optimal demodulation, and overcomes the influence of frequency offset by setting order tolerance and adopting a special normalization strategy, so that the rotation frequency and meshing frequency of the gear can be accurately positioned. Attached Figure Description

[0068] Figure 1 This is a flowchart of the method for detecting abnormal gear support status in the integrated transmission device according to the present invention;

[0069] Figure 2 The image shows the vibration signal waveform and spectrum measured at the pump drive section of the integrated transmission device in this embodiment of the invention.

[0070] Figure 3 This is a schematic diagram of the estimated optimal demodulation frequency in an embodiment of the present invention;

[0071] Figure 4 This is the amplitude result at the gear frequency order after order tracking using the optimal demodulation frequency in this embodiment of the invention;

[0072] Figure 5 This is a comparison diagram of the rotational impact measurement of gear frequency and the rotational impact measurement of engine input frequency in an embodiment of the present invention. Detailed Implementation

[0073] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0074] To solve the above technical problems, the present invention provides a vibration signal demodulation integrated transmission gear support anomaly detection system, the system being used to detect anomalies in the support state of gears in an integrated transmission device;

[0075] The system includes: a vibration sensor, a multi-channel data acquisition device, a computer, and a data analysis module installed on the computer;

[0076] The vibration sensor is connected to a multi-channel data acquisition device to convert the vibration characteristics of the integrated transmission device into an electrical signal input.

[0077] The multi-channel data acquisition device is used to convert electrical signals into digital signals and input them into a connected computer.

[0078] The data analysis module installed on the computer is used to detect abnormalities in the gear support status of the integrated transmission device, analyze digital signals, and provide detection results on whether the gear has malfunctioned.

[0079] The vibration sensor is used to detect vibrations when the integrated transmission is operating in a specific gear and under loading conditions, at an engine speed of f. s At that time, vibration signals were collected for no less than 10 seconds.

[0080] The multi-channel data acquisition device is used to convert the vibration signal into a digital signal and input it into a connected computer.

[0081] The data analysis module installed on the computer is used to detect abnormalities in the gear support status of the integrated transmission device, analyze digital signals, and provide detection results on whether the gear has failed.

[0082] The specific testing process includes:

[0083] Step 1: Perform preprocessing on the vibration signal in digital form, including removing the mean and trend term, to obtain the discrete vibration signal s(t). i ), i = 1, 2, ..., N, where t i This represents N sampling times, and then the engine speed f is calculated based on the transmission ratio of the integrated transmission system under the condition of no transmission error. s The corresponding gear frequency f ms ;

[0084] Step 2: Considering that the gear frequency f is fluctuating or changing when the engine speed is in a state of flux or variation. ms The corresponding signal components are represented by a class of amplitude-frequency modulation (AM-FM) signal models:

[0085]

[0086] Where j is the imaginary unit, θ0 is the initial phase, and a(t) represents the instantaneous amplitude;

[0087] Define frequency demodulation operator and the corresponding frequency modulation operator Among them, f d (t) > 0 is called the demodulation frequency, f c (t)>0 is related to f ms The corresponding carrier wave is used to multiply the signal by the demodulation operator to obtain the demodulated signal:

[0088]

[0089] a d (t) represents the instantaneous amplitude of the demodulated signal;

[0090] When the demodulation frequency equals the instantaneous gear rotation frequency, i.e., f d (t)=f ms (t), the signal is demodulated as:

[0091]

[0092] At this point, the frequency modulation term in the demodulated signal phase is eliminated, and the signal becomes a frequency modulation term concentrated on the carrier f. c For pure amplitude-modulated signals near (t), the bandwidth reaches its minimum.

[0093] To estimate the optimal demodulation frequency, the smoothness of the signal is evaluated using the energy of the second derivative of the demodulated signal, which reflects the signal's bandwidth. Specifically, the following optimization problem is solved:

[0094]

[0095] Where i = 1, 2, ..., K represents the gear rotation frequency f under consideration. ms The higher harmonic order, a” id (t) represents a id The second difference of (t) is given, where ||·||² is the 2-norm; the optimal demodulation frequency is obtained by solving the above optimization problem using the Lagrange multiplier method or other optimization methods.

[0096] Step 3: [Regarding...] Numerical integration yields the angle rotated by the gear in the angular domain of the integrated transmission device. Through the Equal-interval resampling yields the resampled vibration signal s. o (t i If i = 1, 2, ..., N, then in s o (t i In this process, the distortion of gear frequency amplitude caused by fluctuations or changes in engine speed is effectively eliminated; the engine frequency f s Defined as first order, for the resampled signal s o (t i Order tracking is performed on i = 1, 2, ..., N to obtain the order spectrum S. o (f k In the solved order spectrum, the meshing order of the gear is equal to the number of teeth on the gear. in accordance with The order components near the order can be used, combined with existing modulation sideband amplitude techniques, to determine whether there is a gear pair fault.

[0097] Step 4: Considering transmission error factors, set the order tolerance range [Ω]. min ,Ω max The amplitudes of the order components within the tolerance range of the gear frequency and its higher harmonics are normalized. For the higher harmonics of the frequency, the amplitude is also divided by the maximum amplitude within the tolerance range of the gear frequency fundamental frequency, i.e.:

[0098]

[0099] In the formula, the subscript [K] indicates the order tolerance range of the Kth harmonic component of the gear frequency;

[0100] Step 5: Define the gear frequency f ms Rotational impact measurement I m (f ms )as follows:

[0101]

[0102] Similarly, the rotational impact measure I of the engine input frequency can be calculated. m (f s ), if I m (f ms )>I m (f s If the gear is unbalanced, it indicates a gear imbalance fault; otherwise, it indicates that the gear is in good condition.

[0103] In step 5, the rotating impact measurement I m (f ms ) and I m (f s The larger the ratio of ), the more serious the gear imbalance fault.

[0104] In general, if I m (f ms ) / I m (f s If the value is greater than 2, it indicates that the gear imbalance is quite serious.

[0105] Furthermore, this invention provides a comprehensive transmission gear support anomaly detection method based on vibration signal demodulation, which is implemented using the aforementioned comprehensive transmission gear support anomaly detection system based on vibration signal demodulation. The method includes the following steps:

[0106] Step 0: Operate the integrated transmission device in a specific gear and under loading conditions, with the engine speed at f. s At that time, a vibration sensor should be used to collect vibration signals for no less than 10 seconds;

[0107] Step 1: Perform preprocessing on the vibration signal in digital form, including removing the mean and trend term, to obtain the discrete vibration signal s(t). i ), i = 1, 2, ..., N, where t i This represents N sampling times, and then the engine speed f is calculated based on the transmission ratio of the integrated transmission system under the condition of no transmission error. s The corresponding gear frequency f ms ;

[0108] Step 2: Considering that the gear frequency f is fluctuating or changing when the engine speed is in a state of flux or variation. ms The corresponding signal components are represented by a class of amplitude-frequency modulation (AM-FM) signal models:

[0109]

[0110] Where j is the imaginary unit, θ0 is the initial phase, and a(t) represents the instantaneous amplitude;

[0111] Define frequency demodulation operator and the corresponding frequency modulation operator Among them, f d (t) > 0 is called the demodulation frequency, f c (t)>0 is related to f ms The corresponding carrier wave is used to multiply the signal by the demodulation operator to obtain the demodulated signal:

[0112]

[0113] a d (t) represents the instantaneous amplitude of the demodulated signal;

[0114] When the demodulation frequency equals the instantaneous gear rotation frequency, i.e., f d (t)=f ms (t), the signal is demodulated as:

[0115]

[0116] At this point, the frequency modulation term in the demodulated signal phase is eliminated, and the signal becomes a frequency modulation term concentrated on the carrier f. c For pure amplitude-modulated signals near (t), the bandwidth reaches its minimum.

[0117] To estimate the optimal demodulation frequency, the smoothness of the signal is evaluated using the energy of the second derivative of the demodulated signal, which reflects the signal's bandwidth. Specifically, the following optimization problem is solved:

[0118]

[0119] Where i = 1, 2, ..., K represents the gear rotation frequency f under consideration.ms The higher harmonic order, a i " d (t) represents a id The second difference of (t) is given, where ||·||² is the 2-norm; the optimal demodulation frequency is obtained by solving the above optimization problem using the Lagrange multiplier method or other optimization methods.

[0120] Step 3: [Regarding...] Numerical integration yields the angle rotated by the gear in the angular domain of the integrated transmission device. Through the Equal-interval resampling yields the resampled vibration signal s. o (t i If i = 1, 2, ..., N, then in s o (t i In this process, the distortion of gear frequency amplitude caused by fluctuations or changes in engine speed is effectively eliminated; the engine frequency f s Defined as first order, for the resampled signal s o (t i Order tracking is performed on i = 1, 2, ..., N to obtain the order spectrum S. o (f k In the solved order spectrum, the meshing order of the gear is equal to the number of teeth on the gear. in accordance with The order components near the order can be used, combined with existing modulation sideband amplitude techniques, to determine whether there is a gear pair fault.

[0121] Step 4: Considering transmission error factors, set the order tolerance range [Ω]. min ,Ω max The amplitudes of the order components within the tolerance range of the gear frequency and its higher harmonics are normalized. For the higher harmonics of the frequency, the amplitude is also divided by the maximum amplitude within the tolerance range of the gear frequency fundamental frequency, i.e.:

[0122]

[0123] In the formula, the subscript [K] indicates the order tolerance range of the Kth harmonic component of the gear frequency;

[0124] Step 5: Define the gear frequency f ms Rotational impact measurement I m (f ms )as follows:

[0125]

[0126] Similarly, the rotational impact measure I of the engine input frequency can be calculated. m (fs ), if I m (f ms )>I m (f s If the gear is unbalanced, it indicates a gear imbalance fault; otherwise, it indicates that the gear is in good condition.

[0127] In step 5, the rotating impact measurement I m (f ms ) and I m (f s The larger the ratio of ), the more serious the gear imbalance fault.

[0128] In general, if I m (f ms ) / I m (f s If the value is greater than 2, it indicates that the gear imbalance is quite serious.

[0129] Example 1

[0130] This embodiment provides a comprehensive transmission gear support anomaly detection method based on vibration signal demodulation, such as... Figure 1 As shown, the method includes the following steps:

[0131] Step 1: Operate the integrated transmission in forward fourth gear with 50% load, at an engine speed of 2300 RPM (corresponding to a rotational frequency f). s When the frequency is 2300 / 60 = 38.33 Hz, an accelerometer and a multi-channel data acquisition device are used to collect a 10-second vibration signal above the pump unit drive of the integrated transmission device. After analog-to-digital conversion by the multi-channel data acquisition device, the vibration signal is input into the computer in the form of a digital signal. After preprocessing by the data analysis module to remove the mean and trend term, the discrete vibration signal s(t) is obtained. i ), i = 1, 2, ..., N, where t i This represents N sampling times. The vibration signal waveform and spectrum measured at the pump drive section of the integrated transmission device in this embodiment are shown below. Figure 2 As shown. Furthermore, based on the transmission ratio of the integrated transmission system, the engine speed f under conditions of no transmission error is calculated. s =38.33Hz corresponds to the pump gear rotation frequency f ms =49.59Hz.

[0132] Step 2, consider the gear frequency f ms And its second and third harmonics, i.e., K=3, use the Lagrange multiplier method or other optimization methods to solve the following problem regarding the pump set gear frequency f. ms The optimization of the bandwidth of the demodulated signals of its second and third harmonic components:

[0133]

[0134] Among them, a id (t) represents the demodulated signal corresponding to the i-th harmonic component of the pump gear frequency. The instantaneous amplitude, a” id (t) represents a id The second difference of (t), ||·||² is the 2-norm. The pump gear frequency and its second and third harmonic components are represented by the following amplitude-frequency modulation (AM-FM) signal model:

[0135]

[0136] The corresponding frequency demodulation operator is Where j is the imaginary unit and θ0 is the initial phase. Solving the above optimization problem using the Lagrange multiplier method or other optimization methods yields the optimal demodulation frequency. like Figure 3 As shown, the demodulation frequency actually corresponds to the instantaneous frequency of the gear rotation.

[0137] Step 3, for Numerical integration yields the angle rotated by the pump unit gear in the angular domain of the integrated transmission device. Through the Equal-interval resampling yields the resampled vibration signal s. o (t i If i = 1, 2, ..., N, then in s o (t i In this process, the distortion of the pump gear frequency amplitude caused by fluctuations or changes in engine speed is effectively eliminated. The engine speed f... s Defined as first order, for the resampled signal s o (t i Order tracking is performed on i = 1, 2, ..., N to obtain the order spectrum S. o (f k ),like Figure 4 As shown, the order spectrum simultaneously marks the order components corresponding to the engine speed and the pump gear speed.

[0138] Step 4: Considering factors such as transmission errors, set the order tolerance range [Ω]. min ,Ω max [0.98, 1.02], normalize the amplitudes of the order components within the tolerance range of the pump gear frequency and its higher harmonics. For the higher harmonics of the frequency, the amplitude is also divided by the maximum amplitude within the tolerance range of the gear frequency fundamental frequency, i.e.:

[0139]

[0140] In the formula, the subscript [K] indicates the order tolerance range of the Kth harmonic component of the pump gear rotation frequency.

[0141] Step 5, calculate the pump set gear frequency f ms Rotational impact measurement I m (f ms )as follows:

[0142]

[0143] Similarly, the rotational impact measure I of the engine input frequency is also calculated. m (f s In this embodiment, the engine input frequency I m (f s The rotational impact measure of the pump set gear frequency is 0.00167. m (f ms The value is 0.00189, such as Figure 5 As shown, it is obvious that I m (f ms )>I m (f s This indicates a gear imbalance fault, indicated by the rotational impact measurement I. m (f ms ) and I m (f s The ratio of 1.13 is less than 2, indicating that the gear support condition is abnormal and the fault is relatively minor.

[0144] This invention belongs to the field of fault detection technology for integrated transmission systems in tracked vehicles, specifically relating to a method and system for detecting abnormal gear support in integrated transmission systems using vibration signal demodulation. Existing technologies can only detect common fault types such as pitting, wear, and tooth breakage in typical gears, lacking corresponding detection methods and judgment criteria for detecting abnormal gear support conditions. Furthermore, existing technologies do not consider the transmission errors introduced by the inherent complex transmission relationships of integrated transmission systems, thus failing to handle frequency shifts and amplitude distortions caused by these errors. Additionally, the invention addresses the problem that the rotational and meshing frequencies of commonly used gear support shaft fixing types cannot be accurately located in the frequency spectrum. This invention addresses the problem of severe faults caused by abnormal support conditions in typical gear support types of integrated transmission systems by proposing a multi-harmonic optimal demodulation method and a rotational impact measurement criterion. This effectively detects abnormal gear support conditions, considers the frequency shifts and amplitude distortions caused by inherent transmission errors in integrated transmission systems, eliminates amplitude distortion through multi-harmonic optimal demodulation, and overcomes the influence of frequency shifts by setting order tolerances and employing a special normalization strategy.

[0145] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A comprehensive transmission gear support anomaly detection system for vibration signal demodulation, characterized in that, The system is used to detect abnormal support conditions of gears in a comprehensive transmission device. The system includes: a vibration sensor, a multi-channel data acquisition device, a computer, and a data analysis module installed on the computer; The vibration sensor is connected to a multi-channel data acquisition device to convert the vibration characteristics of the integrated transmission device into an electrical signal input. The multi-channel data acquisition device is used to convert electrical signals into digital signals and input them into a connected computer. The data analysis module installed on the computer is used to detect abnormalities in the gear support status of the integrated transmission device, analyze digital signals, and provide detection results on whether the gear has failed. The vibration sensor is used to detect vibrations when the integrated transmission is operating in a specific gear and under loading conditions, at an engine speed of f. s At that time, a vibration signal of no less than 10 seconds was collected; The multi-channel data acquisition device is used to convert the vibration signal into a digital signal and input it into a connected computer. The data analysis module installed on the computer is used to detect abnormalities in the gear support status of the integrated transmission device, analyze digital signals, and provide detection results on whether the gear has failed. The specific testing process includes: Step 1: Perform preprocessing on the vibration signal in digital form, including removing the mean and trend term, to obtain the discrete vibration signal s(t). i ), i = 1, 2, ..., N, where t i This represents N sampling times, and then the engine speed f is calculated based on the transmission ratio of the integrated transmission system under the condition of no transmission error. s The corresponding gear frequency f ms ; Step 2: Considering that the gear frequency f is fluctuating or changing when the engine speed is in a state of flux or variation. ms The corresponding signal components are represented by a class of amplitude-frequency modulation (AM-FM) signal models: Where j is the imaginary unit, θ0 is the initial phase, and a(t) represents the instantaneous amplitude; Define frequency demodulation operator and the corresponding frequency modulation operator Among them, f d (t) > 0 is called the demodulation frequency, f c (t)>0 is related to f ms The corresponding carrier wave is used to multiply the signal by the demodulation operator to obtain the demodulated signal: a d (t) represents the instantaneous amplitude of the demodulated signal; When the demodulation frequency equals the instantaneous gear rotation frequency, i.e., f d (t)=f ms (t), the signal is demodulated as: At this point, the frequency modulation term in the demodulated signal phase is eliminated, and the signal becomes a frequency modulation term concentrated on the carrier f. c For pure amplitude-modulated signals near (t), the bandwidth reaches its minimum. To estimate the optimal demodulation frequency, the smoothness of the signal is evaluated using the energy of the second derivative of the demodulated signal, which reflects the signal's bandwidth. Specifically, the following optimization problem is solved: Where i = 1, 2, ..., K represents the gear rotation frequency f under consideration. ms The higher harmonic order, a i " d (t) represents a id The second difference of (t) is given, where ||·||² is the 2-norm; the optimization problem is solved using the Lagrange multiplier method to obtain the optimal demodulation frequency. Step 3: [Regarding...] Numerical integration yields the angle rotated by the gear in the angular domain of the integrated transmission device. Through the Equal-interval resampling yields the resampled vibration signal s. o (t i If i = 1, 2, ..., N, then in s o (t i In this process, the distortion of gear frequency amplitude caused by fluctuations or changes in engine speed is effectively eliminated; the engine frequency f s Defined as first order, for the resampled signal s o (t i Order tracking is performed on i = 1, 2, ..., N to obtain the order spectrum S. o (f k In the solved order spectrum, the meshing order of the gear is equal to the number of teeth on the gear. in accordance with The order components near the order can be used, combined with existing modulation sideband amplitude techniques, to determine whether there is a gear pair fault. Step 4: Considering transmission error factors, set the order tolerance range [Ω]. min ,Ω max The amplitudes of the order components within the tolerance range of the gear frequency and its higher harmonics are normalized. For the higher harmonics of the frequency, the amplitude is also divided by the maximum amplitude within the tolerance range of the gear frequency fundamental frequency, i.e.: In the formula, the subscript [K] indicates the order tolerance range of the Kth harmonic component of the gear frequency; Step 5: Define the gear frequency f ms Rotational impact measurement I m (f ms )as follows: Similarly, the rotational impact measure I of the engine input frequency can be calculated. m (f s ), if I m (f ms )>I m (f s If the gear is unbalanced, it indicates a gear imbalance fault; otherwise, it indicates that the gear is in good condition.

2. The integrated transmission gear support anomaly detection system for vibration signal demodulation as described in claim 1, characterized in that, In step 5, the rotating impact measurement I m (f ms ) and I m (f s The larger the ratio of ), the more severe the gear imbalance fault.

3. The integrated transmission gear support anomaly detection system for vibration signal demodulation as described in claim 2, characterized in that, If I m (f ms ) / I m (f s If the value is greater than 2, it indicates that the gear imbalance is quite serious.

4. A method for detecting abnormalities in integrated transmission gear supports by demodulating vibration signals, wherein the method is implemented using the integrated transmission gear support abnormality detection system by demodulating vibration signals as described in any one of claims 1-3, characterized in that, The method includes the following steps: Step 0: Operate the integrated transmission device in a specific gear and under loading conditions, with the engine frequency at f. s At that time, a vibration sensor should be used to collect vibration signals for no less than 10 seconds; Step 1: Perform preprocessing on the vibration signal in digital form, including removing the mean and trend term, to obtain the discrete vibration signal s(t). i ), i = 1, 2, ..., N, where t i This represents N sampling times, and then the engine speed f is calculated based on the transmission ratio of the integrated transmission system under the condition of no transmission error. s The corresponding gear frequency f ms ; Step 2: Considering that the gear frequency f is fluctuating or changing when the engine speed is in a state of flux or variation. ms The corresponding signal components are represented by a class of amplitude-frequency modulation (AM-FM) signal models: Where j is the imaginary unit, θ0 is the initial phase, and a(t) represents the instantaneous amplitude; Define frequency demodulation operator and the corresponding frequency modulation operator Among them, f d (t) > 0 is called the demodulation frequency, f c (t)>0 is related to f ms The corresponding carrier wave is used to multiply the signal by the demodulation operator to obtain the demodulated signal: a d (t) represents the instantaneous amplitude of the demodulated signal; When the demodulation frequency equals the instantaneous gear rotation frequency, i.e., f d (t)=f ms (t), the signal is demodulated as: At this point, the frequency modulation term in the demodulated signal phase is eliminated, and the signal becomes a frequency modulation term concentrated on the carrier f. c For pure amplitude-modulated signals near (t), the bandwidth reaches its minimum. To estimate the optimal demodulation frequency, the smoothness of the signal is evaluated using the energy of the second derivative of the demodulated signal, which reflects the signal's bandwidth. Specifically, the following optimization problem is solved: Where i = 1, 2, ..., K represents the gear rotation frequency f under consideration. ms The higher harmonic order, a″ id (t) represents a id The second difference of (t) is given, where ||·||² is the 2-norm; the optimization problem is solved using the Lagrange multiplier method to obtain the optimal demodulation frequency. Step 3: [Regarding...] Numerical integration yields the angle rotated by the gear in the angular domain of the integrated transmission device. Through the Equal-interval resampling yields the resampled vibration signal s. o (t i If i = 1, 2, ..., N, then in s o (t i In this process, the distortion of gear frequency amplitude caused by fluctuations or changes in engine speed is effectively eliminated; the engine frequency f s Defined as first order, for the resampled signal s o (t i Order tracking is performed on i = 1, 2, ..., N to obtain the order spectrum S. o (f k In the solved order spectrum, the meshing order of the gear is equal to the number of teeth on the gear. in accordance with The order components near the order can be used, combined with existing modulation sideband amplitude techniques, to determine whether there is a gear pair fault. Step 4: Considering transmission error factors, set the order tolerance range [Ω]. min ,Ω max The amplitudes of the order components within the tolerance range of the gear frequency and its higher harmonics are normalized. For the higher harmonics of the frequency, the amplitude is also divided by the maximum amplitude within the tolerance range of the gear frequency fundamental frequency, i.e.: In the formula, the subscript [K] indicates the order tolerance range of the Kth harmonic component of the gear frequency; Step 5: Define the gear frequency f ms Rotational impact measurement I m (f ms )as follows: Similarly, the rotational impact measure I of the engine input frequency can be calculated. m (f s ), if I m (f ms )>I m (f s If the gear is unbalanced, it indicates a gear imbalance fault; otherwise, it indicates that the gear is in good condition.

5. The integrated transmission gear support anomaly detection method based on vibration signal demodulation as described in claim 4, characterized in that, In step 5, the rotating impact measurement I m (f ms ) and I m (f s The larger the ratio of ), the more severe the gear imbalance fault.

6. The integrated transmission gear support anomaly detection method based on vibration signal demodulation as described in claim 5, characterized in that, If I m (f ms ) / I m (f s If the value is greater than 2, it indicates that the gear imbalance is quite serious.

7. The integrated transmission gear support anomaly detection method based on vibration signal demodulation as described in claim 6, characterized in that, The system takes into account the transmission errors introduced by the inherent complex transmission relationship of the integrated transmission device structure. It eliminates amplitude distortion through multi-harmonic optimal demodulation, and overcomes the influence of frequency offset by setting order tolerance and adopting a special normalization strategy. It can accurately position the rotation frequency and meshing frequency of the gears.

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