Gear knock feature evaluation method and system based on band-pass filtering and synchronous averaging

Abstract

The application discloses a gear knock feature evaluation method and system based on band-pass filtering and synchronous averaging, which comprises the following steps: collecting mixed vibration signals of a full frequency band of a gear system to be measured; performing band-pass filtering on the mixed vibration signals of the full frequency band to obtain mixed vibration signals in a frequency band of interest, and obtaining mixed vibration characteristic parameters according to the mixed vibration signals in the frequency band of interest; performing synchronous averaging processing on the mixed vibration signals in the frequency band of interest to obtain synchronous time-domain signals of each shaft of the gear system to be measured in the frequency band of interest, and obtaining synchronous time-domain characteristic parameters of each shaft according to the synchronous time-domain signals of each shaft of the gear system to be measured; judging whether the gear system to be measured has a knock fault according to a comparison result of the mixed vibration characteristic parameters and preset mixed vibration characteristic parameter thresholds, and locking a fault shaft of the gear system according to a comparison result of the synchronous time-domain characteristic parameters of each shaft and preset synchronous time-domain characteristic parameter thresholds of each shaft if the gear system to be measured has the knock fault.

Description

Technical Field

[0001] This invention relates to the field of gear vibration and noise detection technology, specifically to a method and system for evaluating gear collision characteristics based on bandpass filtering and synchronous averaging. Background Technology

[0002] Gear systems may experience impacts during manufacturing, transportation, and assembly, leading to vibration and noise issues. Current off-line testing primarily identifies impact characteristics by comparing the crease and kurtosis factors of time-domain signals. Traditional methods typically calculate these metrics based on full-band data, failing to focus on the main frequency range of gear meshing and unable to accurately pinpoint the shaft where the fault occurs. Summary of the Invention

[0003] The purpose of this invention is twofold: firstly, to provide a gear impact feature evaluation system based on bandpass filtering and synchronous averaging; and secondly, to provide a gear impact feature evaluation method based on bandpass filtering and synchronous averaging. This system and method can focus on the gear impact frequency band through bandpass filtering technology, avoiding full-band noise interference and improving the identification of impact features. Crest and Kurtosis address single-peak and multi-peak problems respectively, enabling differentiated control. Fault location efficiency is improved; the combination of hybrid channel and synchronous channel analysis narrows the fault range to a specific shaft, reducing maintenance costs.

[0004] To achieve this objective, the present invention provides a gear collision feature evaluation system based on bandpass filtering and synchronous averaging, comprising:

[0005] The parameter acquisition module is used to collect mixed vibration signals across the entire frequency band of the gear system under test;

[0006] The data processing module is used to perform bandpass filtering on the mixed vibration signal across the entire frequency band to obtain the mixed vibration signal within the frequency band of interest, and to obtain the mixed vibration characteristic parameters based on the mixed vibration signal within the frequency band of interest; and to perform synchronous averaging on the mixed vibration signal within the frequency band of interest to obtain the synchronous time domain signal of each shaft of the gear system under test within the frequency band of interest, and to obtain the synchronous time domain characteristic parameters of each shaft based on the synchronous time domain signal of each shaft of the gear system under test.

[0007] The fault location module is used to compare the mixed vibration characteristic parameters with the preset mixed vibration characteristic parameter thresholds. Based on the comparison results, it determines whether there is a collision fault in the gear system under test. If there is a collision fault in the gear system under test, it compares the synchronous time domain characteristic parameters of each shaft with the preset synchronous time domain characteristic parameter thresholds of each shaft. Based on the comparison results, it locks the faulty shaft of the gear system.

[0008] Regarding the sampling frequency, some optimized technical solutions include: when acquiring mixed vibration signals across the entire frequency band of the gear system under test, the sampling frequency should be more than twice the maximum vibration frequency of the gear system under test.

[0009] This invention uses a non-full-band range for processing. In some preferred embodiments, the mixed vibration signal with frequencies within the frequency range of interest in the mixed vibration signal of the gear system under test across the full frequency band is the mixed vibration signal within the frequency range of interest. The lower limit of the frequency range of interest is the minimum frequency that the human ear can detect, and the upper limit of the frequency range is the main modal frequency of the gear system under test.

[0010] Furthermore, a method for obtaining the mixed vibration signal within the frequency band of interest includes: using an IIR filter to extract the mixed vibration signal with frequencies within the frequency range of interest from the mixed vibration signal across the entire frequency band of the gear system under test, thus obtaining the mixed vibration signal within the frequency band of interest for the gear system under test. The IIR filter is a bandpass filter and can be implemented in software.

[0011] To obtain the synchronous time-domain signal, some preferred methods include a synchronous averaging processing module for the mixed vibration signal within the frequency band of interest. This module performs synchronous averaging processing on the mixed vibration signal within the frequency band of interest, thereby obtaining the synchronous time-domain signal of each shaft of the gear system under test within the frequency band of interest. The method includes: dividing the mixed vibration signal within the frequency band of interest of the gear system under test into multiple segments according to the rotation periods of the input shaft, intermediate shaft, and output shaft of the gear system under test; aligning the multiple signal segments of the input shaft, intermediate shaft, and output shaft of the gear system under test obtained from the multiple segments according to the time of the rotation period of each shaft; adding the data of the aligned signal segments point by point and taking the average value to obtain the synchronous time-domain signal of the input shaft, intermediate shaft, and output shaft composed of the average value.

[0012] Furthermore, methods for obtaining hybrid vibration characteristic parameters based on hybrid vibration signals within the frequency band of interest include:

[0013] Calculate the mean of the mixed vibration signal within the frequency band of interest: Calculate the root mean square value of the mixed vibration signal within the frequency band of interest: Calculate the peak value of the mixed vibration signal within the frequency band of interest: x peak =max|x(n)|;

[0014] Calculate the peak factor of the mixed vibration signal within the frequency band of interest: Calculate the kurtosis factor of the mixed vibration signal within the band of interest:

[0015]

[0016] Where N is the total number of mixed vibration signals in the frequency band of interest, n is the nth data in the mixed vibration signals in the frequency band of interest, x(n) is the value corresponding to the nth data in the mixed vibration signals in the frequency band of interest, and the peak factor and kurtosis factor of the mixed vibration signals in the frequency band of interest are the mixed vibration characteristic parameters of the mixed vibration signals in the frequency band of interest.

[0017] The method of obtaining the synchronous time domain characteristic parameters of each shaft based on the synchronous time domain signal of each shaft of the gear system under test uses the above formula to obtain the peak factor and kurtosis factor of the synchronous time domain signal of each shaft as the synchronous time domain characteristic parameters of each shaft.

[0018] Furthermore, the method for comparing the hybrid vibration characteristic parameters with preset hybrid vibration characteristic parameter thresholds and determining whether the gear system under test has a collision fault based on the comparison results includes: comparing the peak factor and kurtosis factor of the hybrid vibration signal in the frequency band of interest with preset peak factor thresholds and kurtosis factor thresholds of the hybrid vibration signal in the frequency band of interest, respectively. When at least one of the peak factor and kurtosis factor of the hybrid vibration signal in the frequency band of interest is greater than the corresponding set threshold, it indicates that the gear system under test has a collision fault; otherwise, the gear system under test does not have a collision fault.

[0019] Furthermore, the method of comparing the synchronous time-domain characteristic parameters of each axis with preset threshold values ​​for the synchronous time-domain characteristic parameters of each axis, and locking the faulty axis of the gear system based on the comparison results, includes: when it is determined that there is a collision fault in the gear system under test, the peak factor and kurtosis factor of the synchronous time-domain signal of each axis are compared with preset threshold values ​​for the peak factor and kurtosis factor of the synchronous time-domain signal of each axis, respectively. When at least one of the peak factor and kurtosis factor of the synchronous time-domain signal of a single axis is greater than the corresponding set threshold, the axis can be locked to have a collision fault.

[0020] Furthermore, according to the gear collision feature evaluation method based on bandpass filtering and synchronous averaging of the system, it includes:

[0021] Acquire mixed vibration signals across the entire frequency band of the gear system under test;

[0022] Bandpass filtering is performed on the mixed vibration signal across the entire frequency band to obtain the mixed vibration signal within the frequency band of interest. The mixed vibration characteristic parameters are obtained based on the mixed vibration signal within the frequency band of interest. Synchronous averaging is performed on the mixed vibration signal within the frequency band of interest to obtain the synchronous time-domain signal of each shaft of the gear system under test within the frequency band of interest. The synchronous time-domain characteristic parameters of each shaft are obtained based on the synchronous time-domain signal of each shaft of the gear system under test.

[0023] The mixed vibration characteristic parameters are compared with the preset mixed vibration characteristic parameter thresholds. Based on the comparison results, it is determined whether there is a collision fault in the gear system under test. If there is a collision fault in the gear system under test, the synchronous time domain characteristic parameters of each shaft are compared with the preset synchronous time domain characteristic parameter thresholds of each shaft. Based on the comparison results, the faulty shaft of the gear system is identified.

[0024] The beneficial effects of this invention are as follows: Existing technologies for assessing collision characteristics in gear systems employ full-band signal analysis using peak factor (Crest) and kurtosis factor (Kurtosis). This leads to non-meshing frequency noise interference in the identification of key features and fails to distinguish faulty shafts, necessitating disassembly for troubleshooting and increasing maintenance costs. This invention focuses on the gear meshing frequency band using bandpass filtering technology, avoiding full-band noise interference and improving the identification of collision characteristics. Crest and Kurtosis address single-peak and multi-peak issues respectively, enabling differentiated management. Fault location efficiency is improved; the combination of hybrid and synchronous channel analysis narrows the fault range to a specific shaft, reducing maintenance costs. Attached Figure Description

[0025] Figure 1 This is a comparison chart of the Crest / Kurtosis distribution of the full-band (VSG) and bandpass filter (VSGBP) of this invention;

[0026] Figure 2 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0028] Example 1

[0029] like Figure 2 As shown, a gear collision feature evaluation system based on bandpass filtering and synchronous averaging includes:

[0030] The parameter acquisition module is used to collect mixed vibration signals across the entire frequency band of the gear system under test;

[0031] The data processing module is used to perform bandpass filtering on the mixed vibration signal across the entire frequency band to obtain the mixed vibration signal within the frequency band of interest, and to obtain the mixed vibration characteristic parameters based on the mixed vibration signal within the frequency band of interest; and to perform synchronous averaging on the mixed vibration signal within the frequency band of interest to obtain the synchronous time domain signal of each shaft of the gear system under test within the frequency band of interest, and to obtain the synchronous time domain characteristic parameters of each shaft based on the synchronous time domain signal of each shaft of the gear system under test.

[0032] The fault location module is used to compare the mixed vibration characteristic parameters with the preset mixed vibration characteristic parameter thresholds. Based on the comparison results, it determines whether there is a collision fault in the gear system under test. If there is a collision fault in the gear system under test, it compares the synchronous time domain characteristic parameters of each shaft with the preset synchronous time domain characteristic parameter thresholds of each shaft. Based on the comparison results, it locks the faulty shaft of the gear system.

[0033] Gear systems include rotating machinery such as gearboxes and electric drive systems. Gear impact characteristic assessment is applicable to the off-line testing and quality control of rotating machinery such as gearboxes and electric drive systems. At the end of the production line, it tests for vibration and noise problems caused by impacts during the manufacturing, transportation, and assembly processes of gear systems, and replaces or repairs gear systems with severe impact failures.

[0034] In some embodiments, the electric drive assembly of an electric vehicle is equivalent to a gearbox. When evaluating the impact characteristics of the electric drive assembly gearbox, testing is generally conducted under predetermined off-line conditions. When the vehicle is traveling at high speed, the knocking noise caused by the collision between gears inside the electric drive assembly gearbox is masked by wind noise, road noise, and other noises. The knocking noise caused by the collision between gears in the electric drive assembly gearbox is generally more noticeable at low to medium motor speeds. Therefore, the impact fault test condition for the electric drive assembly gearbox is set within the motor speed range of 3000–5000 rpm. When the impact on the electric drive assembly gearbox is minor and the vehicle is under heavy load, the impact characteristics are weakened due to gear tooth surface deformation. However, if the motor torque is too low, the gears in the reduction gearbox system may knock back and forth due to low torque control precision, leading to misjudgments. Therefore, the torque is generally set to 5–10 Nm during impact evaluation. The off-line conditions for an electric drive system in a project are shown in Table 1. The off-line conditions are as follows:

[0035] Table 1: Operating Conditions of Electric Drive Systems After Production

[0036]

[0037] In some technical solutions, when collecting mixed vibration signals across the entire frequency band of the gear system under test, the sampling frequency is more than twice the maximum vibration frequency of the gear system under test.

[0038] According to the Nyquist sampling theorem, to sample and reconstruct a continuous-time signal without distortion, the sampling frequency must be greater than twice the highest frequency component of the original signal. This is to avoid aliasing between the sampled signal and the original signal and to ensure accurate reconstruction of the sampled signal. The highest frequency of a gear system can be, but is not limited to, 10,000 Hz.

[0039] In some embodiments, when evaluating the impact characteristics of the electric drive assembly gearbox under set offline operating conditions, the gearbox gear system impact evaluation under constant speed gliding and constant speed driving conditions is performed on the test bench. The measuring point of the vibration sensor VSG is set at the intermediate shaft bearing seat of the gearbox to facilitate the simultaneous acquisition of vibration characteristics of the input shaft, intermediate shaft and output shaft. Generally, the highest vibration frequency of the gearbox is less than or equal to 10000Hz. Based on experience, selecting a vibration sensor VSG with a sampling frequency of 100kHz can achieve a better sampling effect. The vibration sensor acquires the mixed vibration signal of the input shaft, intermediate shaft and output shaft. The mixed vibration signal is the vibration signal that combines the vibration signals of the input shaft, intermediate shaft and output shaft.

[0040] In some technical solutions, the mixed vibration signal with frequencies falling within the frequency range of interest from the mixed vibration signal across the entire frequency band of the gear system under test is considered the mixed vibration signal within the frequency range of interest. The lower limit of the frequency range of interest is the smallest frequency that the human ear can detect, and the upper limit of the frequency range is the dominant modal frequency of the gear system under test. The dominant modal frequency is the dominant natural frequency exhibited by the gear system during free vibration, corresponding to the core vibration mode of the system in a specific direction (such as axial or radial) or a specific component (such as gears or bearings). Using the dominant modal frequency as the upper limit of the frequency range of interest can accurately reflect the system's response characteristics to impacts and maximize the sensitivity of the crest factor and kurtosis factor to impact failures.

[0041] In some embodiments, when the impact vibration noise of the gear system is imperceptible to the human ear, its impact can be ignored. Therefore, the lower limit of the frequency range of concern is the minimum frequency that the human ear can detect, 20Hz. The main modal frequency of the electric drive assembly gearbox system is within 3000Hz, so the upper limit of the frequency range of concern is the main modal frequency of the gear system. The main modal frequency of the gear system can be, but is not limited to, 3000Hz. The frequency range of concern is set to 20-3000Hz, and the mixed vibration signal within the frequency range of concern is the vibration signal with a frequency between 20-3000Hz in the mixed vibration signal of the input shaft, intermediate shaft, and output shaft.

[0042] Some technical solutions involve obtaining mixed vibration signals within the frequency band of interest by using an IIR filter to extract mixed vibration signals with frequencies within the frequency range of interest from the mixed vibration signals of the gear system under test across the entire frequency band, thereby obtaining the mixed vibration signals within the frequency band of interest of the gear system under test.

[0043] In full-band signals, noise in non-meshing frequency bands interferes with the calculation of crest and kurtosis factors, while bandpass filtering can remove irrelevant components, making the impact characteristics more prominent. By filtering out interference in non-impact frequency bands (such as low-frequency bearing vibration and high-frequency electromagnetic noise) based on the gear meshing frequency and the frequency range of impact signals, and retaining the frequency band signals directly related to gear failures, the signal-to-noise ratio of the sampled signal can be significantly improved.

[0044] In some embodiments, a vibration sensor (VSG) collects the full-band mixed vibration time-domain signal of the gear system, and then an IIR filter extracts the mixed vibration time-domain signal located in the frequency range of interest, i.e., the mixed vibration signal within the frequency range of interest. A test bench for evaluating the impact characteristics of the electric drive assembly gearbox is connected to a host computer, which contains analysis software. The host computer receives the mixed vibration signal collected by the VSG and manually inputs the frequency range of interest to be extracted using the filtering function (i.e., the IIR filter) within the analysis software. The IIR filter automatically extracts the mixed vibration signal within the frequency range of interest, i.e., the mixed vibration signal within the frequency range of interest.

[0045] In some technical solutions, the method of synchronously averaging the mixed vibration signal within the frequency band of interest to obtain the synchronous time-domain signal of each shaft of the gear system under test within the frequency band of interest includes: dividing the mixed vibration signal within the frequency band of interest of the gear system under test into multiple segments according to the rotation period of the input shaft, intermediate shaft and output shaft of the gear system under test; aligning the multiple signal segments of the input shaft, intermediate shaft and output shaft of the gear system under test obtained by multiple segments according to the time of the rotation period of each shaft; adding the data of the aligned signal segments point by point and taking the average value to obtain the synchronous time-domain signal of the input shaft, intermediate shaft and output shaft composed of the average value.

[0046] Gears and drive shafts work together to transmit power. The mixed vibration signals within the frequency band of interest of the gear system under test are repeatedly divided, aligned, and superimposed according to the rotational period of each shaft (input shaft, intermediate shaft, output shaft) and then averaged. Periodic fault signals (such as gear collisions) are retained due to their phase consistency, while random noise (such as background vibration and electromagnetic interference) cancels each other out during the averaging process due to their phase randomness. By synchronously averaging the signals from the input shaft, intermediate shaft, and output shaft respectively, the vibration characteristics of each shaft can be extracted independently. The vibration characteristics of the gears are the same as those of the shafts they are connected to. Based on the vibration characteristics of each shaft, it can be determined whether there is a collision fault with the gears mounted on the shaft.

[0047] In some embodiments, the rotation period of the input shaft is set to T1, the rotation period of the intermediate shaft is set to T2, and the rotation period of the output shaft is set to T3. The number of divisions is set to 128. The mixed vibration signal within the frequency band of interest is automatically segmented by a Discom analysis system installed in the host computer. The Discom analysis system divides the signal into 128 time-domain signal segments with a period of T1. The two endpoints of the 128 time-domain signal segments with a period of T1 are aligned. The data within the aligned 128 time-domain signal segments with a period of T1 are added together according to time points and averaged. The selection of time points includes, but is not limited to, all time points within one period that are 0.01s apart, and can be determined according to the actual situation. This yields the synchronous time-domain signal with a rotation period of T1 (i.e., the synchronous time-domain signal of the input shaft). Similarly, the synchronous time-domain signal with a rotation period of T2 (i.e., the synchronous time-domain signal of the intermediate shaft) and the synchronous time-domain signal with a rotation period of T3 (i.e., the synchronous time-domain signal of the output shaft) can be obtained.

[0048] Some technical solutions involve obtaining hybrid vibration characteristic parameters from hybrid vibration signals within the frequency band of interest, including:

[0049] Calculate the mean of the mixed vibration signal within the frequency band of interest:

[0050] Calculate the root mean square value of the mixed vibration signal within the frequency band of interest:

[0051] Calculate the peak value of the mixed vibration signal within the frequency band of interest: x peak =max|x(n)|;

[0052] Calculate the peak factor of the mixed vibration signal within the frequency band of interest:

[0053] Calculate the kurtosis factor of the mixed vibration signal within the band of interest:

[0054]

[0055] Where N is the total number of mixed vibration signals in the frequency band of interest, n is the nth data in the mixed vibration signals in the frequency band of interest, x(n) is the value corresponding to the nth data in the mixed vibration signals in the frequency band of interest, and the peak factor and kurtosis factor of the mixed vibration signals in the frequency band of interest are the mixed vibration characteristic parameters of the mixed vibration signals in the frequency band of interest.

[0056] Similarly, methods for calculating the synchronization time-domain signals of each axis to obtain the synchronization time-domain characteristic parameters of each axis include: in some embodiments, obtaining the synchronization time-domain characteristic parameters of the input axis synchronization time-domain signal based on the synchronization time-domain signal (input axis synchronization time-domain signal) with a rotation period of T1:

[0057] Calculate the mean of the synchronization time-domain signal with a rotation period of T1:

[0058] Calculate the root mean square value of the synchronous time-domain signal with a rotation period of T1:

[0059] Calculate the peak value of the synchronization time-domain signal with a rotation period of T1: x peak1 =max|x(n1)|;

[0060] Calculate the peak factor of a synchronous time-domain signal with a rotation period of T1:

[0061] Calculate the kurtosis factor of a synchronous time-domain signal with a rotation period of T1:

[0062]

[0063] Where N1 is the total number of data in the synchronous time-domain signal with a rotation period of T1, n1 is the n1th data in the synchronous time-domain signal with a rotation period of T1, x(n1) is the value corresponding to the n1th data in the synchronous time-domain signal with a rotation period of T1, and the peak factor Crest1 and kurtosis factor Kurtosis1 are the synchronous time-domain characteristic parameters of the input axis synchronous time-domain signal.

[0064] Similarly, based on the synchronous time-domain signal with a rotation period of T2, the synchronous time-domain characteristic parameters of the intermediate shaft synchronous time-domain signal, namely the peak factor Crest2 and the kurtosis factor Kurtosis2, can be obtained; based on the synchronous time-domain signal with a rotation period of T3, the synchronous time-domain characteristic parameters of the output shaft synchronous time-domain signal, namely the peak factor Crest3 and the kurtosis factor Kurtosis3, can be obtained.

[0065] Crest (peak factor) and kurtosis (base factor) are used to detect different types of impact defects. Crest reflects the ratio of the maximum impact intensity to the average vibration energy in the vibration signal. In other words, cinching can detect when a gear edge is impacted and develops a noticeable dent. Each time the faulty gear rotates to the dented area, it produces a large vibration, resulting in a spike in the vibration signal. Kurtosis reflects the density of extreme values ​​in the vibration signal; the more small impact marks present on the gear system, the higher the kurtosis value. By analyzing the mixed vibration signal within the desired frequency band and the synchronous time-domain signal of each shaft, it is possible to quickly determine whether an impact defect exists in the gear system and the type of such defect.

[0066] It should be noted that the thresholds for the peak factor and kurtosis factor of the synchronous time domain signal of each axis and the mixed vibration signal in the frequency band of interest can be determined based on historical experience, or a normal distribution model can be established based on the historical data of the peak factor and kurtosis factor of the gear system. The preset values ​​of the peak factor and kurtosis factor are taken as the average value of the normal distribution model + 3σ as the limit, where σ is the deviation value of the normal distribution model.

[0067] In some technical solutions, the method of comparing the mixed vibration characteristic parameters with preset mixed vibration characteristic parameter thresholds to determine whether the gear system under test has a collision fault includes: comparing the peak factor and kurtosis factor of the mixed vibration signal in the focus frequency band with preset peak factor and kurtosis factor thresholds for the mixed vibration signal in the focus frequency band, respectively. When at least one of the peak factor and kurtosis factor of the mixed vibration signal in the focus frequency band is greater than the corresponding set threshold, it indicates that the gear system under test has a collision fault; otherwise, the gear system under test does not have a collision fault. This method quickly determines whether the gear system has a collision fault by using the mixed vibration signal in the focus frequency band without synchronous averaging, avoiding redundant shaft system analysis on fault-free gear system samples and shortening the detection cycle. After determining that the gear system under test has a fault through the mixed vibration signal in the focus frequency band, analyzing the synchronous time-domain signals of each shaft to pinpoint the transmission shaft where the gear with the collision fault is located can improve the detection efficiency of the gear system collision fault.

[0068] In some embodiments, based on historical experience, the thresholds for Crest and Kurtosis of the mixed vibration signal in the band of interest are both set to 10. When the values ​​of Crest and / or Kurtosis of the mixed vibration signal in the band of interest are greater than 10, it indicates that the gearbox of the electric drive assembly has a collision fault.

[0069] In some technical solutions, the method of comparing the synchronous time-domain characteristic parameters of each axis with preset threshold values ​​for the synchronous time-domain characteristic parameters of each axis, and then identifying the faulty axis of the gear system based on the comparison results, includes: after determining that there is a collision fault in the gear system under test, comparing the peak factor and kurtosis factor of the synchronous time-domain signal of each axis with preset threshold values ​​for the peak factor and kurtosis factor of the synchronous time-domain signal of each axis, respectively. When at least one of the peak factor and kurtosis factor of the synchronous time-domain signal of a single axis is greater than the corresponding set threshold, the axis can be identified as having a collision fault. By comparing the peak factor and kurtosis factor of the synchronous time-domain signal of each axis with the preset threshold values ​​for the peak factor and kurtosis factor of the synchronous time-domain signal of each axis, the faulty axis can be quickly identified. After identifying the faulty axis, it is more convenient and faster to replace the faulty gear, avoiding the need to disassemble the entire gear system and manually identify the specific faulty gear, thus saving time in collision fault assessment.

[0070] In some embodiments, based on historical experience, the threshold values ​​for Crest and Kurtosis of the synchronization time-domain signals of each axis are set to 8 and 6, respectively. When a collision fault is determined in the gearbox of the electric drive assembly, the specific location of the collision fault needs to be pinpointed based on the synchronization time-domain signals. When the value of the peak factor Crest1 of the input axis synchronization time-domain signal exceeds 8, it indicates that the gear on the input axis has a large dent from the collision. When the value of the kurtosis factor Kurtosis1 exceeds 6, it indicates that the gear on the axis has multiple minor collision marks. When both the peak factor Crest1 and the kurtosis factor Kurtosis1 exceed the set thresholds, it indicates that the gear on the input axis has both a large dent from the collision and multiple minor collision marks, and this axis can be identified as the faulty axis. The gear installed on the faulty axis has a collision fault, and the host computer marks the input axis as the faulty axis. Similarly, the peak factor Crest2 and the kurtosis factor Kurtosis2 can be used to determine whether the intermediate axis is the faulty axis, and the peak factor Crest3 and the kurtosis factor Kurtosis3 can be used to determine whether the output axis is the faulty axis. It should be noted that after the electric drive assembly gearbox has completed the collision fault assessment and been installed in the vehicle, if customer complaints are still received regarding collision noise during vehicle operation, the threshold values ​​of Crest and Kurtosis for the electric drive assembly gearbox during the collision fault assessment can be appropriately lowered based on the Crest and Kurtosis values ​​of the electric drive assembly gearbox of the complained vehicle. If the electric drive assembly gearbox does not emit collision noise during the collision fault assessment, but the host computer still marks the faulty shaft, the threshold values ​​of Crest and Kurtosis for the electric drive assembly gearbox during the collision fault assessment can be appropriately increased based on the Crest and Kurtosis values ​​of that electric drive assembly gearbox.

[0071] Figure 1 This is a comparison of the Crest / Kurtosis distribution between the full-band frequency (VSG) and band-pass filter (VSGBP) frequencies under constant speed drive conditions during the production line testing of the same electric drive assembly gearbox. White dots represent statistically significant outliers, and black asterisks represent faulty data samples. The VSG sampling frequency is 100kHz, and the analysis frequency range is 0–50kHz. Figure 1The upper part is a comparison chart of the distribution of Crest for full-band (VSG) and bandpass filtered (VSGBP). The vertical axis represents the calculated Crest value of the electric drive assembly gearbox. The horizontal axis represents, in order, the input shaft-mixed-VSG (full-band mixed vibration signal with input shaft speed as reference), input shaft-mixed-VSGBP (mixed vibration signal of the frequency band of interest with input shaft speed as reference), input shaft-synchronized-VSG (input shaft full-band synchronization time domain signal), input shaft-synchronized-VSGBP (input shaft of interest frequency band synchronization time domain signal), intermediate shaft-synchronized-VSG (intermediate shaft full-band synchronization time domain signal), intermediate shaft-synchronized-VSGBP (intermediate shaft of interest frequency band synchronization time domain signal), output shaft-synchronized-VSG (output shaft full-band synchronization time domain signal), and output shaft-synchronized-VSGBP (output shaft of interest frequency band synchronization time domain signal). Figure 1 The lower half of the graph compares the distribution of Kurtosis for VSG and bandpass-filtered VSGBP, with the vertical axis representing the calculated Kurtosis value of the drive assembly gearbox, and the horizontal axis being the same as the distribution comparison graph of Crest for VSG and bandpass-filtered VSGBP. From... Figure 1 As can be seen from the comparative analysis of the Crest values ​​of input shaft-hybrid-VSG and input shaft-hybrid-VSGBP: The calculation and normal distribution statistics of the input shaft Crest value using the full-band hybrid vibration signal show that the number of abnormal samples obtained from the statistical results is greater than the number of abnormal samples obtained from the mixed vibration signal after bandpass filtering. Furthermore, the deviation in the number of abnormal samples under the full-band hybrid vibration signal is larger, indicating that bandpass filtering can reduce the probability and deviation range of sample data abnormalities caused by interference from non-interested frequency bands in the full-band hybrid vibration signal. Additionally, the value of fault samples obtained from the impact feature assessment of the input shaft based on the full-band hybrid vibration signal is smaller than the value of fault samples obtained from the mixed vibration signal after bandpass filtering. This indicates that bandpass filtering can effectively reduce noise interference from non-interested frequency bands in the full-band hybrid vibration signal, highlighting the abnormal Crest values ​​caused by impact features. The comparative analysis of the Crest values ​​of input axis-synchronous-VSG and input axis-synchronous-VSGBP, intermediate axis-synchronous-VSG and intermediate axis-synchronous-VSGBP, and output axis-synchronous-VSG and output axis-synchronous-VSGBP is similar to the comparative analysis of the Crest values ​​of input axis-mixed-VSG and input axis-mixed-VSGBP. Similarly, the comparative analysis of the Kurtosis values ​​of VSG and bandpass filter VSGPP is similar to the comparative analysis of the Crest values ​​of the Kurtosis values ​​of VSG and bandpass filter VSGPP.

[0072] Conclusion: By focusing the gear impact frequency band using bandpass filtering (VSGBP), the distribution range of abnormal data in the Crest and Kurtosis values ​​of the samples was significantly reduced, and the probability of abnormal data occurrence was decreased, thus improving the accuracy of impact fault detection results. Full-band (VSG) impact fault assessment results have low accuracy due to noise interference, while bandpass filtering (VSGBP) combined with synchronous channel analysis effectively achieves the location and interception of gear impact defects.

[0073] Example 2

[0074] The gear collision feature evaluation method based on bandpass filtering and synchronous averaging of the system includes:

[0075] Acquire mixed vibration signals across the entire frequency band of the gear system under test;

[0076] Bandpass filtering is performed on the mixed vibration signal across the entire frequency band to obtain the mixed vibration signal within the frequency band of interest. The mixed vibration characteristic parameters are obtained based on the mixed vibration signal within the frequency band of interest. Synchronous averaging is performed on the mixed vibration signal within the frequency band of interest to obtain the synchronous time-domain signal of each shaft of the gear system under test within the frequency band of interest. The synchronous time-domain characteristic parameters of each shaft are obtained based on the synchronous time-domain signal of each shaft of the gear system under test.

[0077] The mixed vibration characteristic parameters are compared with the preset mixed vibration characteristic parameter thresholds. Based on the comparison results, it is determined whether there is a collision fault in the gear system under test. If there is a collision fault in the gear system under test, the synchronous time domain characteristic parameters of each shaft are compared with the preset synchronous time domain characteristic parameter thresholds of each shaft. Based on the comparison results, the faulty shaft of the gear system is identified.

[0078] Example 3

[0079] The present invention also includes a computer program product comprising a computer program / instruction that, when executed by a processor, implements the steps of the above-described gear collision feature evaluation method based on bandpass filtering and synchronous averaging.

[0080] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A gear collision feature evaluation system based on bandpass filtering and synchronous averaging, characterized in that it include: The parameter acquisition module is used to collect mixed vibration signals across the entire frequency band of the gear system under test; The data processing module performs bandpass filtering on the mixed vibration signal across the entire frequency band to obtain the mixed vibration signal within the frequency band of interest. Based on the mixed vibration signal within the frequency band of interest, it obtains the mixed vibration characteristic parameters. The module also performs synchronous averaging on the mixed vibration signal within the frequency band of interest to obtain the synchronous time-domain signal of each shaft of the gear system under test within the frequency band of interest. Based on the synchronous time-domain signal of each shaft of the gear system under test, it obtains the synchronous time-domain characteristic parameters of each shaft. The mixed vibration signal within the frequency range of interest in the mixed vibration signal of the gear system under test across the entire frequency band is the mixed vibration signal within the frequency band of interest. The lower limit of the frequency range of interest is the minimum frequency that the human ear can detect, and the upper limit of the frequency range is the main modal frequency of the gear system under test. It also includes a synchronous averaging processing module for mixed vibration signals within the frequency band of interest, which is used to perform synchronous averaging processing on mixed vibration signals within the frequency band of interest. The method for obtaining the synchronous time-domain signals of each shaft of the gear system under test within the frequency band of interest includes: dividing the mixed vibration signal of the gear system under test within the frequency band of interest into multiple segments according to the rotation periods of the input shaft, intermediate shaft, and output shaft of the gear system under test; aligning the multiple signal segments of the input shaft, intermediate shaft, and output shaft of the gear system under test obtained from the multiple segments according to the time of the rotation period of each shaft; adding the data of the aligned signal segments point by point and taking the average value to obtain the synchronous time-domain signals of the input shaft, intermediate shaft, and output shaft composed of the average value; The fault location module is used to compare the mixed vibration characteristic parameters with the preset mixed vibration characteristic parameter thresholds. Based on the comparison results, it determines whether there is a collision fault in the gear system under test. If there is a collision fault in the gear system under test, it compares the synchronous time domain characteristic parameters of each shaft with the preset synchronous time domain characteristic parameter thresholds of each shaft. Based on the comparison results, it locks the faulty shaft of the gear system.

2. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 1, characterized in that: When collecting mixed vibration signals across the entire frequency band of the gear system under test, the sampling frequency should be more than twice the maximum vibration frequency of the gear system under test.

3. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 1, characterized in that: It also includes a mixed vibration signal acquisition module within the frequency band of interest, used to acquire mixed vibration signals within the frequency band of interest; the acquisition method includes: using an IIR filter to extract mixed vibration signals with frequencies within the frequency range of interest from the mixed vibration signals of the gear system under test across the entire frequency band, thereby obtaining the mixed vibration signals within the frequency band of interest of the gear system under test.

4. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 1, characterized in that: Methods for obtaining hybrid vibration characteristic parameters from hybrid vibration signals within the frequency band of interest include: Calculate the mean of the mixed vibration signal within the frequency band of interest: ; Calculate the root mean square value of the mixed vibration signal within the frequency band of interest: ; Calculate the peak value of the mixed vibration signal within the frequency band of interest: ; Calculate the peak factor of the mixed vibration signal within the frequency band of interest: ; Calculate the kurtosis factor of the mixed vibration signal within the band of interest: ； Where N is the total number of mixed vibration signals in the frequency band of interest, n is the nth data in the mixed vibration signals in the frequency band of interest, x(n) is the value corresponding to the nth data in the mixed vibration signals in the frequency band of interest, and the peak factor and kurtosis factor of the mixed vibration signals in the frequency band of interest are the mixed vibration characteristic parameters of the mixed vibration signals in the frequency band of interest.

5. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 4, characterized in that: The method for determining whether the gear system under test has a collision fault by comparing the hybrid vibration characteristic parameters with preset hybrid vibration characteristic parameter thresholds includes: comparing the peak factor and kurtosis factor of the hybrid vibration signal in the frequency band of interest with preset peak factor thresholds and kurtosis factor thresholds of the hybrid vibration signal in the frequency band of interest, respectively. When at least one of the peak factor and kurtosis factor of the hybrid vibration signal in the frequency band of interest is greater than the corresponding set threshold, it indicates that the gear system under test has a collision fault; otherwise, the gear system under test does not have a collision fault.

6. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 5, characterized in that: The method of comparing the synchronous time-domain characteristic parameters of each axis with preset threshold values ​​for the synchronous time-domain characteristic parameters of each axis, and locking the faulty axis of the gear system based on the comparison results, includes: when it is determined that there is a collision fault in the gear system under test, the peak factor and kurtosis factor of the synchronous time-domain signal of each axis are compared with preset threshold values ​​for the peak factor and kurtosis factor of the synchronous time-domain signal of each axis, respectively. When at least one of the peak factor and kurtosis factor of the synchronous time-domain signal of a single axis is greater than the corresponding set threshold, the axis can be locked to have a collision fault.

7. The gear collision feature evaluation method based on bandpass filtering and synchronous averaging according to any one of claims 1 to 6, characterized in that, It includes: Acquire mixed vibration signals across the entire frequency band of the gear system under test; Bandpass filtering is performed on the mixed vibration signal across the entire frequency band to obtain the mixed vibration signal within the frequency band of interest. The mixed vibration characteristic parameters are obtained based on the mixed vibration signal within the frequency band of interest. Synchronous averaging is performed on the mixed vibration signal within the frequency band of interest to obtain the synchronous time-domain signal of each shaft of the gear system under test within the frequency band of interest. The synchronous time-domain characteristic parameters of each shaft are obtained based on the synchronous time-domain signal of each shaft of the gear system under test. The mixed vibration characteristic parameters are compared with the preset mixed vibration characteristic parameter thresholds. Based on the comparison results, it is determined whether there is a collision fault in the gear system under test. If there is a collision fault in the gear system under test, the synchronous time domain characteristic parameters of each shaft are compared with the preset synchronous time domain characteristic parameter thresholds of each shaft. Based on the comparison results, the faulty shaft of the gear system is identified.

8. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method described in claim 7.

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