Gear bump characteristic evaluation method and system based on band-pass filtering and synchronous averaging

Abstract

The invention discloses a gear bump characteristic evaluation method and system based on band-pass filtering and synchronous averaging. The gear bump characteristic evaluation method comprises the steps of collecting full-band mixed vibration signals of a gear system to be detected; performing band-pass filtering on the full-band mixed vibration signal to obtain a mixed vibration signal in a concerned frequency band, and obtaining a mixed vibration characteristic parameter according to the mixed vibration signal in the concerned frequency band; performing synchronous average processing on the mixed vibration signals in the concerned frequency band to obtain synchronous time domain signals of each shaft of the gear system to be tested in the concerned frequency band, 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 tested; according to a comparison result of the mixed vibration characteristic parameter and a preset mixed vibration characteristic parameter threshold value, whether the gear system to be detected has a collision fault or not is judged; and locking a fault shaft of the gear system according to a comparison result of the synchronous time domain characteristic parameter of each shaft and a preset synchronous time domain characteristic parameter threshold value of each shaft.

Description

Technical Field

[0001] The present invention relates to the technical field of gear vibration noise detection, and in particular to a gear collision feature evaluation method and system based on bandpass filtering and synchronous averaging. Background Art

[0002] Gear systems can experience knocks and collisions during manufacturing, transportation, and assembly, leading to vibration and noise. Current end-of-line testing primarily identifies knock characteristics by comparing the crest factor (Crest) and kurtosis (Kurtosis) of time-domain signals. Traditional methods typically calculate metrics based on full-band data, failing to focus on the primary frequency range of gear system meshing and failing to precisely pinpoint the faulty axis. Summary of the Invention

[0003] The present invention aims to provide, on the one hand, a gear knock feature assessment system based on bandpass filtering and synchronous averaging, and, on the other hand, a gear knock feature assessment method based on bandpass filtering and synchronous averaging. This system and method can focus on the gear knock frequency band through bandpass filtering technology, avoiding full-band noise interference and improving the recognition of knock features. Crest and Kurtosis respectively address single-peak and multi-peak issues, achieving differentiated management and control. Fault location efficiency is improved, and hybrid channel and synchronous channel analysis are combined to narrow the fault scope to a specific axis, reducing maintenance costs.

[0004] To achieve this purpose, the present invention designs a gear collision feature evaluation system based on bandpass filtering and synchronous averaging, which includes:

[0005] The parameter acquisition module is used to collect the mixed vibration signal of the gear system under test in the full frequency band;

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

[0007] The fault location module is used to compare the mixed vibration characteristic parameters with the preset mixed vibration characteristic parameter threshold, and determine whether the gear system to be tested has a collision fault based on the comparison results. If the gear system to be tested has a collision fault, the synchronous time domain characteristic parameters of each axis are compared with the preset synchronous time domain characteristic parameter threshold of each axis, and the faulty axis of the gear system is locked based on the comparison results.

[0008] Regarding the sampling frequency, some optimized technical solutions include: when collecting the mixed vibration signal of the full frequency band of the gear system to be tested, the sampling frequency is more than twice the maximum vibration frequency of the gear system to be tested.

[0009] The present invention uses a non-full frequency band range for processing. In some preferred embodiments, the mixed vibration signal of the full-frequency band mixed vibration signal of the gear system to be measured whose frequency is in the frequency interval of interest is the mixed vibration signal within the frequency interval of interest. The lower limit value of the frequency interval of interest is the minimum frequency that can be captured by the human ear, and the upper limit value of the frequency interval is the main modal frequency of the gear system to be measured.

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

[0011] In order to obtain synchronized time domain signals, some preferred methods include a synchronized averaging processing module for mixed vibration signals within the frequency band of interest, which is used to perform synchronized averaging processing on the mixed vibration signals within the frequency band of interest, thereby obtaining synchronized time domain signals of each shaft of the gear system to be tested within the frequency band of interest. The method includes: dividing the mixed vibration signals within the frequency band of interest of the gear system to be tested multiple times according to the rotation periods of the input shaft, intermediate shaft and output shaft of the gear system to be tested, aligning the multiple signal segments of the input shaft, intermediate shaft and output shaft of the gear system to be tested obtained by the multiple divisions 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 synchronized time domain signals of the input shaft, intermediate shaft and output shaft composed of the average value.

[0012] Furthermore, the method for obtaining mixed vibration characteristic parameters according to the mixed vibration signal in the frequency band of interest includes:

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

[0014] Calculate the crest factor of a mixed vibration signal within the frequency band of interest: Compute the kurtosis factor of a mixed vibration signal in the frequency band of interest:

[0015]

[0016] Wherein, N is the total number of data of the mixed vibration signal within the frequency band of interest, n is the n-th data in the mixed vibration signal within the frequency band of interest, x(n) is the value corresponding to the n-th data in the mixed vibration signal within the frequency band of interest, and the peak factor and kurtosis factor of the mixed vibration signal within the frequency band of interest are mixed vibration characteristic parameters of the mixed vibration signal within the frequency band of interest;

[0017] According to the method of obtaining the synchronous time domain characteristic parameters of each axis of the gear system to be tested, the peak factor and kurtosis factor of the synchronous time domain signal of each axis are obtained using the synchronous time domain signal data of each axis using the above formula as the synchronous time domain characteristic parameters of each axis.

[0018] Furthermore, the method of comparing the mixed vibration characteristic parameters with the preset mixed vibration characteristic parameter thresholds and judging whether the gear system to be tested has a collision fault according to the comparison results includes: comparing the peak factor and kurtosis factor of the mixed vibration signal in the frequency band of interest with the preset peak factor threshold and kurtosis factor threshold of the mixed vibration signal in the frequency band of interest, respectively; when at least one of the peak factor and kurtosis factor of the mixed vibration signal in the frequency band of interest is greater than the corresponding set threshold, it indicates that the gear system to be tested has a collision fault; otherwise, the gear system to be tested does not have a collision fault.

[0019] Furthermore, the synchronous time domain characteristic parameters of each axis are compared with the preset synchronous time domain characteristic parameter thresholds of each axis, and the method for locking the faulty axis of the gear system according to the comparison results includes: after judging that the gear system to be tested has a collision fault, the peak factor and kurtosis factor of the synchronous time domain signal of each axis are compared with the preset peak factor threshold and kurtosis factor threshold 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 as having a collision fault.

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

[0021] Collect the mixed vibration signal of the gear system under test in the full frequency band;

[0022] Performing bandpass filtering on the mixed vibration signal of the entire frequency band to obtain a mixed vibration signal within the frequency band of interest, and obtaining mixed vibration characteristic parameters based on the mixed vibration signal within the frequency band of interest; performing synchronous averaging processing on the mixed vibration signal within the frequency band of interest to obtain a synchronized time domain signal of each axis of the gear system to be measured within the frequency band of interest, and obtaining synchronized time domain characteristic parameters of each axis based on the synchronized time domain signal of each axis of the gear system to be measured;

[0023] The mixed vibration characteristic parameters are compared with the preset mixed vibration characteristic parameter thresholds, and the comparison results are used to determine whether the gear system to be tested has a collision fault. If the gear system to be tested has a collision fault, the synchronous time domain characteristic parameters of each axis are compared with the preset synchronous time domain characteristic parameter thresholds of each axis, and the faulty axis of the gear system is locked according to the comparison results.

[0024] Beneficial effects of the present invention: When evaluating the collision characteristics of gear systems, the existing technology uses full-band signal analysis peak factor (Crest) and kurtosis factor (Kurtosis), which causes non-meshing frequency noise to interfere with key feature identification, and is unable to distinguish faulty shaft systems, requiring disassembly and investigation, increasing maintenance costs. The present invention focuses on the gear meshing frequency band through bandpass filtering technology, avoiding full-band noise interference and improving collision feature recognition. Crest and Kurtosis target single-peak and multi-peak problems respectively to achieve differentiated management and control. Fault location efficiency is improved by combining hybrid channel and synchronous channel analysis to narrow the fault range to specific shafts and reduce maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a comparison diagram of the Crest / Kurtosis distribution of the full-band (VSG) and band-pass filtering (VSGBP) of the present invention;

[0026] Figure 2 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[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 the mixed vibration signal of the gear system under test in the full frequency band;

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

[0032] The fault location module is used to compare the mixed vibration characteristic parameters with the preset mixed vibration characteristic parameter threshold, and determine whether the gear system to be tested has a collision fault based on the comparison results. If the gear system to be tested has a collision fault, the synchronous time domain characteristic parameters of each axis are compared with the preset synchronous time domain characteristic parameter threshold of each axis, and the faulty axis of the gear system is locked based on the comparison results.

[0033] Gear systems include rotating machinery such as gearboxes and electric drive systems. Gear knock characteristics assessment is applicable to end-of-line testing and quality control of these rotating machinery. At the end of the production line, gear systems are tested for vibration and noise caused by knocks and knocks during manufacturing, transportation, and assembly. Gear systems with severe knock faults are replaced or repaired.

[0034] In some embodiments, the electric drive assembly of an electric vehicle is equivalent to a gearbox. When evaluating the collision characteristics of the electric drive assembly gearbox, it is generally chosen to be tested under the set offline working conditions. When the vehicle is driving at high speed, the knocking noise caused by the collision between the gears inside the electric drive assembly gearbox will be masked by wind noise, road noise and other noises. The knocking noise caused by the collision between the gears of the electric drive assembly gearbox is generally more obvious at low and medium speeds of the motor. Therefore, the collision fault test working condition of the electric drive assembly gearbox is set within the motor speed range of 3000-5000rpm; when the degree of collision of the electric drive assembly gearbox is relatively minor and the vehicle is under heavy load, the deformation of the gear tooth surface will weaken the collision characteristics, and if the motor torque is too small, the gears in the reduction gear system will knock back and forth due to the low torque control accuracy, resulting in misjudgment. Therefore, the torque is generally set to 5-10Nm during the collision evaluation. The offline working condition settings of the electric drive system of a project are shown in Table 1. The offline working conditions are:

[0035] Table 1: Offline operating conditions of electric drive system

[0036]

[0037] In some technical solutions, when collecting the mixed vibration signal of the full frequency band of the gear system to be measured, the sampling frequency is more than twice the maximum vibration frequency of the gear system to be measured.

[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 ensure accurate restoration of the sampled signal. The maximum frequency of a gear system can be, but is not limited to, 10,000 Hz.

[0039] In some embodiments, when the collision characteristics of the electric drive assembly gearbox are evaluated under the set off-line working conditions, the collision evaluation of the reduction gear system under uniform speed sliding and uniform speed driving conditions will be carried out on the test bench respectively, and the measuring point of the vibration sensor VSG will be set at the intermediate shaft bearing seat of the reduction gearbox to facilitate the simultaneous collection of the vibration characteristics of the three shafts of the input shaft, intermediate shaft and output shaft. Generally, the maximum vibration frequency of the gearbox is less than or equal to 10000Hz. Based on experience, a vibration sensor VSG with a sampling frequency of 100kHz can achieve a better sampling effect. The vibration sensor collects a mixed vibration signal of the input shaft, intermediate shaft and output shaft. The mixed vibration signal is a vibration signal in which the vibration signals of the three shafts of the input shaft, intermediate shaft and output shaft are mixed together.

[0040] In some technical solutions, the mixed vibration signal within the frequency range of interest in the full-band mixed vibration signal of the gear system to be tested 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 can be detected by the human ear, and the upper limit of the frequency range is the main modal frequency of the gear system to be tested. The main 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, radial) or specific components (such as gears, bearings). Using the main modal frequency as the upper limit of the frequency range of interest can accurately reflect the response characteristics of the system to collision impact and maximize the sensitivity of the crest factor (Crest) and kurtosis factor (Kurtosis) to collision failure.

[0041] In some embodiments, the impact of the gear system's vibration noise, which is not detectable by the human ear, can be ignored. Therefore, the lower limit of the frequency range of interest is 20 Hz, the minimum frequency detectable by the human ear. The main modal frequency of the electric drive assembly gearbox system is within 3000 Hz, so the upper limit of the frequency range of interest is the main modal frequency of the gear system, which can be, but is not limited to, 3000 Hz. The frequency range of interest is set to 20-3000 Hz, and the mixed vibration signal within the frequency band of interest, i.e., the vibration signal with a frequency between 20 and 3000 Hz in the mixed vibration signal of the input shaft, intermediate shaft, and output shaft, is considered.

[0042] In some technical solutions, the method for obtaining a mixed vibration signal within a frequency band of interest includes: using an IIR filter to extract the mixed vibration signal with a frequency in the frequency range of interest from the mixed vibration signal of the full frequency band of the gear system to be tested, and obtaining the mixed vibration signal within the frequency band of interest of the gear system to be tested.

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

[0044] In some embodiments, a full-band mixed vibration time-domain signal of the gear system is collected using a vibration sensor (VSG), and then an IIR filter is used to extract the mixed vibration time-domain signal within the frequency range of interest, i.e., the mixed vibration signal within the frequency range of interest. A test bench for evaluating the collision characteristics of an electric drive assembly gearbox is connected to a host computer, which has analysis software installed therein. The host computer receives the mixed vibration signal collected by the vibration sensor (VSG), and uses the filtering function (i.e., IIR filter) within the analysis software to manually input the frequency range of interest to be extracted. The IIR filter then 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, a method for performing synchronous averaging processing on a mixed vibration signal within a frequency band of interest to obtain synchronized time domain signals of each shaft of the gear system to be tested within the frequency band of interest includes: dividing the mixed vibration signal within the frequency band of interest of the gear system to be tested multiple times according to the rotation periods of the input shaft, intermediate shaft and output shaft of the gear system to be tested, aligning the multiple signal segments of the input shaft, intermediate shaft and output shaft of the gear system to be tested obtained by the multiple divisions 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 synchronized time domain signals 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 for the gear system under test are divided multiple times according to the rotation period of each shaft (input shaft, intermediate shaft, and output shaft), aligned, and then superimposed to take the average value. Periodic fault signals (such as gear knocks) 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 the randomness of their phase. By synchronously averaging the signals of the input shaft, intermediate shaft, and output shaft, the vibration characteristics of each shaft can be independently extracted. The vibration characteristics of a gear are identical to those of the shaft to which it is connected. The vibration characteristics of each shaft can be used to determine whether there is a knock fault with the gear 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, the rotation period of the output shaft is set to T3, and the number of divisions is set to 128 times. The mixed vibration signal in the frequency band of interest is automatically divided by the Discom analysis system installed in the host computer. The Discom analysis system divides and obtains 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 in the aligned 128 time domain signal segments with a period of T1 are added according to time points and averaged. The selection of time points includes but is not limited to all time points separated by 0.01s within a period, which can be determined according to actual conditions. A synchronous time domain signal with a rotation period of T1 (i.e., the synchronous time domain signal of the input shaft) is obtained. Similarly, a synchronous time domain signal with a rotation period of T2 (i.e., the synchronous time domain signal of the intermediate shaft) and a 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] In some technical solutions, a method for obtaining mixed vibration characteristic parameters based on a mixed vibration signal within a frequency band of interest includes:

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

[0050] Calculate the RMS value of the mixed vibration signal within the frequency band of interest:

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

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

[0053] Compute the kurtosis factor of a mixed vibration signal in the frequency band of interest:

[0054]

[0055] Wherein, N is the total number of data of the mixed vibration signal within the frequency band of interest, n is the n-th data in the mixed vibration signal within the frequency band of interest, x(n) is the value corresponding to the n-th data in the mixed vibration signal within the frequency band of interest, and the peak factor and kurtosis factor of the mixed vibration signal within the frequency band of interest are mixed vibration characteristic parameters of the mixed vibration signal within the frequency band of interest;

[0056] Similarly, the method for calculating the synchronous time domain signal of each axis to obtain the synchronous time domain characteristic parameters of each axis includes: in some embodiments, obtaining the synchronous time domain characteristic parameters of the input axis synchronous time domain signal according to the synchronous time domain signal with a rotation period of T1 (the input axis synchronous time domain signal):

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

[0058] Calculate the RMS value of the synchronous time domain signal with a rotation period of T1:

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

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

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

[0062]

[0063] Wherein, N1 is the total number of data of 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 of the synchronous time domain signal with a rotation period of T1, and the peak factor Crest1 and the kurtosis factor Kurtosis1 are the synchronous time domain characteristic parameters of the input axis synchronous time domain signal;

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

[0065] Crest (peak factor) and Kurtosis (kurtosis factor) are used to detect different types of knock defects. Crest reflects the ratio of the maximum impact intensity in the vibration signal to the average vibration energy. In other words, Crest can detect when a significant dent is caused by an impact on the edge of a gear. Each time the faulty gear rotates to the position with a significant dent, it will vibrate significantly, and a spike will appear in the vibration signal. Kurtosis reflects the density of extreme values ​​in the vibration signal. In other words, the more small knock marks there are on the gear system, the greater the kurtosis factor value. By analyzing the mixed vibration signal within the frequency band of interest and the synchronized time domain signals of each axis, it is possible to quickly determine whether a gear system has a knock fault and the type of knock fault.

[0066] It should be noted that the thresholds of 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 the average value of the normal distribution model + 3σ as the limit value, and 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 the preset mixed vibration characteristic parameter thresholds and judging whether the gear system to be tested has a collision fault based on the comparison results includes: comparing the peak factor and kurtosis factor of the mixed vibration signal in the frequency band of interest with the preset peak factor threshold and kurtosis factor threshold of the mixed vibration signal in the frequency band of interest, respectively; when at least one of the peak factor and kurtosis factor of the mixed vibration signal in the frequency band of interest is greater than the corresponding set threshold, it indicates that the gear system to be tested has a collision fault; otherwise, the gear system to be tested does not have a collision fault. By quickly judging whether the gear system has a collision fault through the mixed vibration signal in the frequency band of interest without synchronous averaging, redundant shaft system analysis of fault-free gear system samples is avoided, and the detection cycle is shortened. After judging that the gear system to be tested has a fault through the mixed vibration signal in the frequency band of interest, the synchronous time domain signals of each axis are analyzed, and the transmission shaft where the gear with the collision fault is located is locked, the efficiency of the gear system collision fault detection can be improved.

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

[0069] In some technical solutions, the synchronous time domain characteristic parameters of each axis are compared with the preset synchronous time domain characteristic parameter thresholds of each axis, and the method of locking the faulty axis of the gear system according to the comparison results includes: after determining that the gear system to be tested has a collision fault, the peak factor and kurtosis factor of the synchronous time domain signal of each axis are compared with the preset peak factor threshold and kurtosis factor threshold 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 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 peak factor threshold and kurtosis factor threshold of the synchronous time domain signal of each axis respectively, the faulty axis can be quickly locked. After the faulty axis is locked, it is more convenient and quick to replace the faulty gear, avoiding the need to manually identify the specific faulty gear after disassembling the entire gear system, thus saving time in collision fault assessment.

[0070] In some embodiments, based on historical experience, the Crest threshold of each shaft's synchronous time-domain signal is set to 8, and the Kurtosis threshold is set to 6. When it is determined that the electric drive assembly gearbox has a collision fault, it is necessary to further locate the specific location of the collision fault based on the synchronous time-domain signal. When the peak factor Crest1 of the input shaft's synchronous time-domain signal exceeds 8, it indicates that the gear on the input shaft has a large dent collision. The kurtosis factor Kurtosis1 exceeds 6, indicating that the gear on the shaft has multiple minor collisions. If the peak factor Crest1 and the kurtosis factor Kurtosis1 both exceed the set thresholds, it indicates that the gear on the input shaft has both large dent collisions and multiple minor collisions. This shaft can be identified as a faulty shaft, and the gear installed on the faulty shaft has a collision fault. The host computer marks the input shaft as a faulty shaft. Similarly, the peak factor Crest2 and the kurtosis2 can be used to determine whether the intermediate shaft is a faulty shaft, and the peak factor Crest3 and the kurtosis3 can be used to determine whether the output shaft is a faulty shaft. It should be noted that after the electric drive assembly gearbox completes the collision fault assessment and is installed for use, if customer complaints are still received about collision noise when the vehicle is driving, the Crest and Kurtosis thresholds of the electric drive assembly gearbox during the collision assessment can be appropriately lowered according to the Crest and Kurtosis values ​​of the electric drive assembly gearbox of the complained vehicle during the collision fault assessment. If the electric drive assembly gearbox does not make a collision noise during the collision fault assessment, the upper computer still marks the faulty axis. The Crest and Kurtosis thresholds of the electric drive assembly gearbox during the collision assessment can be appropriately increased according to the Crest and Kurtosis of the electric drive assembly gearbox.

[0071] Figure 1 This is a comparison chart of the Crest / Kurtosis distribution of the full-band (VSG) and band-pass filtered (VSGBP) of the uniform speed drive condition of the same electric drive assembly gearbox. The white dots in the figure are statistically outliers, and the black asterisks are the values ​​of the fault data samples. The VSG sampling frequency is 100kHz, and the analysis frequency range is 0-50kHz. Figure 1The upper part is a distribution comparison diagram of Crest of full-band (VSG) and band-pass filtering (VSGBP). The vertical axis is the calculated Crest value of the electric drive assembly gearbox, and the horizontal axis is input shaft-hybrid-VSG (full-band hybrid vibration signal with input shaft speed as reference), input shaft-hybrid-VSGBP (mixed vibration signal of the frequency band of interest with input shaft speed as reference), input shaft-synchronized-VSG (input shaft full-band synchronized time domain signal), input shaft-synchronized-VSGP (input shaft frequency band of interest synchronized time domain signal), intermediate shaft-synchronized-VSG (intermediate shaft full-band synchronized time domain signal), intermediate shaft-synchronized-VSGP (intermediate shaft frequency band of interest synchronized time domain signal), output shaft-synchronized-VSG (output shaft full-band synchronized time domain signal), output shaft-synchronized-VSGP (output shaft frequency band of interest synchronized time domain signal). Figure 1 The lower part is the distribution comparison diagram of Kurtosis of VSG and band-pass filter VSGBP, the vertical axis is the Kurtosis calculated value of the drive assembly gearbox, and the horizontal axis is the same as the distribution comparison diagram of Crest of VSG and band-pass filter VSGBP. Figure 1 It can be seen that the Crest values ​​of the input shaft-hybrid-VSG and the input shaft-hybrid-VSGBP are compared and analyzed: the Crest value of the input shaft is calculated and normally distributed using the full-band mixed vibration signal. The number of abnormal samples obtained according to the statistical results is greater than the number of abnormal samples obtained according to the mixed vibration signal after band-pass filtering, and the deviation of the number of abnormal samples under the full-band mixed vibration signal is large, indicating that band-pass filtering can reduce the probability and deviation range of sample data abnormality caused by interference from non-focus frequency bands in the full-band mixed vibration signal, and the value of the fault sample obtained by evaluating the collision characteristics of the input shaft according to the full-band mixed vibration signal is smaller than the value of the fault sample obtained according to the mixed vibration signal after band-pass filtering, indicating that band-pass filtering can effectively reduce the noise interference in non-focus frequency bands in the full-band mixed vibration signal, and highlight the Crest abnormal value caused by the collision characteristics. The comparative analysis of the Crest values ​​of the input shaft-synchronous-VSG and the input shaft-synchronous-VSGBP, the intermediate shaft-synchronous-VSG and the intermediate shaft-synchronous-VSGBP, the output shaft-synchronous-VSG and the output shaft-synchronous-VSGBP is the same as the comparative analysis of the Crest values ​​of the input shaft-hybrid-VSG and the input shaft-hybrid-VSGBP. The comparative analysis of the Kurtosis values ​​of VSG and the band-pass filtered VSGBP is the same as the comparative analysis of the Crest values ​​of the Kurtosis of VSG and the band-pass filtered VSGBP.

[0072] Conclusion: By focusing on the gear knock frequency band through bandpass filtering (VSGBP), the distribution range of abnormal data for the sample's crest and kurtosis values ​​is significantly reduced, and the probability of abnormal data occurrence is reduced, thereby improving the accuracy of knock fault detection results. The full-band (VSG) knock fault assessment results are less accurate due to noise interference. However, bandpass filtering (VSGBP) combined with synchronous channel analysis effectively locates and intercepts gear knock defects.

[0073] Example 2

[0074] A gear knock feature evaluation method based on bandpass filtering and synchronous averaging based on the system includes:

[0075] Collect the mixed vibration signal of the gear system under test in the full frequency band;

[0076] Performing bandpass filtering on the mixed vibration signal of the entire frequency band to obtain a mixed vibration signal within the frequency band of interest, and obtaining mixed vibration characteristic parameters based on the mixed vibration signal within the frequency band of interest; performing synchronous averaging processing on the mixed vibration signal within the frequency band of interest to obtain a synchronized time domain signal of each axis of the gear system to be measured within the frequency band of interest, and obtaining synchronized time domain characteristic parameters of each axis based on the synchronized time domain signal of each axis of the gear system to be measured;

[0077] The mixed vibration characteristic parameters are compared with the preset mixed vibration characteristic parameter thresholds, and the comparison results are used to determine whether the gear system to be tested has a collision fault. If the gear system to be tested has a collision fault, the synchronous time domain characteristic parameters of each axis are compared with the preset synchronous time domain characteristic parameter thresholds of each axis, and the faulty axis of the gear system is locked according to the comparison results.

[0078] Example 3

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

[0080] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

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 the mixed vibration signal of the gear system under test in the full frequency band; The data processing module is used to perform bandpass filtering on the mixed vibration signal of the entire frequency band to obtain the mixed vibration signal within the frequency band of interest, and obtain the mixed vibration characteristic parameters based on the mixed vibration signal within the frequency band of interest; perform synchronous averaging processing on the mixed vibration signal within the frequency band of interest to obtain the synchronized time domain signal of each axis of the gear system to be measured within the frequency band of interest, and obtain the synchronized time domain characteristic parameters of each axis based on the synchronized time domain signal of each axis of the gear system to be measured; The fault location module is used to compare the mixed vibration characteristic parameters with the preset mixed vibration characteristic parameter threshold, and determine whether the gear system to be tested has a collision fault based on the comparison results. If the gear system to be tested has a collision fault, the synchronous time domain characteristic parameters of each axis are compared with the preset synchronous time domain characteristic parameter threshold of each axis, and the faulty axis of the gear system is locked based on the comparison results.

2. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 1 is characterized in that: When collecting the mixed vibration signal of the full frequency band of the gear system to be measured, the sampling frequency is more than twice the maximum vibration frequency of the gear system to be measured.

3. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 1 is characterized in that: The mixed vibration signal with a frequency in the frequency range of interest in the full-band mixed vibration signal of the gear system to be tested 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 can be captured by the human ear, and the upper limit of the frequency range is the main modal frequency of the gear system to be tested.

4. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 3 is characterized in that: It also includes a mixed vibration signal acquisition module within the frequency band of interest, which is used to obtain the mixed vibration signal within the frequency band of interest; the acquisition method includes: using an IIR filter to extract the mixed vibration signal with a frequency in the frequency range of interest from the mixed vibration signal of the full frequency band of the gear system to be tested, and obtain the mixed vibration signal within the frequency band of interest of the gear system to be tested.

5. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 1 is characterized in that: It also includes a mixed vibration signal synchronous averaging processing module within the frequency band of interest, which is used to perform synchronous averaging processing on the mixed vibration signal within the frequency band of interest; The method for obtaining the synchronized time domain signals of each shaft of the gear system to be tested within the frequency band of interest includes: dividing the mixed vibration signal within the frequency band of interest of the gear system to be tested multiple times according to the rotation periods of the input shaft, intermediate shaft and output shaft of the gear system to be tested, aligning the multiple signal segments of the input shaft, intermediate shaft and output shaft of the gear system to be tested obtained by the multiple divisions 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 synchronized time domain signals of the input shaft, intermediate shaft and output shaft composed of the average value.

6. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 1, characterized in that: The method for obtaining mixed vibration characteristic parameters according to the mixed vibration signal in the frequency band of interest includes: Compute the mean of a mixed vibration signal within the frequency band of interest: Calculate the RMS value of the mixed vibration signal within the frequency band of interest: Calculate the peak value of the mixed vibration signal in the frequency band of interest: x peak =max|x(n)|; Calculate the crest factor of a mixed vibration signal within the frequency band of interest: Compute the kurtosis factor of a mixed vibration signal in the frequency band of interest: Among them, N is the total number of data of the mixed vibration signal in the frequency band of interest, n is the n-th data in the mixed vibration signal in the frequency band of interest, x(n) is the value corresponding to the n-th data in the mixed vibration signal in the frequency band of interest, and the peak factor and kurtosis factor of the mixed vibration signal in the frequency band of interest are the mixed vibration characteristic parameters of the mixed vibration signal in the frequency band of interest.

7. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 6, characterized in that: The method of comparing the mixed vibration characteristic parameters with the preset mixed vibration characteristic parameter thresholds and judging whether the gear system to be tested has a collision fault according to the comparison results includes: comparing the peak factor and kurtosis factor of the mixed vibration signal in the frequency band of interest with the preset peak factor threshold and kurtosis factor threshold of the mixed vibration signal in the frequency band of interest, respectively; when at least one of the peak factor and kurtosis factor of the mixed vibration signal in the frequency band of interest is greater than the corresponding set threshold, it indicates that the gear system to be tested has a collision fault; otherwise, the gear system to be tested does not have a collision fault.

8. The gear collision feature evaluation system based on bandpass filtering and synchronous averaging according to claim 7, characterized in that: The method of comparing the synchronous time domain characteristic parameters of each axis with the preset synchronous time domain characteristic parameter thresholds of each axis and locking the faulty axis of the gear system according to the comparison results includes: after determining that the gear system to be tested has a collision fault, comparing the peak factor and kurtosis factor of the synchronous time domain signal of each axis with the preset peak factor threshold and kurtosis factor threshold 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 as having a collision fault.

9. The method for evaluating gear collision characteristics based on bandpass filtering and synchronous averaging according to the system of any one of claims 1 to 8, characterized in that: It includes: Collect the mixed vibration signal of the gear system under test in the full frequency band; Performing bandpass filtering on the mixed vibration signal of the entire frequency band to obtain a mixed vibration signal within the frequency band of interest, and obtaining mixed vibration characteristic parameters based on the mixed vibration signal within the frequency band of interest; performing synchronous averaging processing on the mixed vibration signal within the frequency band of interest to obtain a synchronized time domain signal of each axis of the gear system to be measured within the frequency band of interest, and obtaining synchronized time domain characteristic parameters of each axis based on the synchronized time domain signal of each axis of the gear system to be measured; The mixed vibration characteristic parameters are compared with the preset mixed vibration characteristic parameter thresholds, and the comparison results are used to determine whether the gear system to be tested has a collision fault. If the gear system to be tested has a collision fault, the synchronous time domain characteristic parameters of each axis are compared with the preset synchronous time domain characteristic parameter thresholds of each axis, and the faulty axis of the gear system is locked according to the comparison results.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to claim 9 are implemented.

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