TWI238926B - Singularity analysis method and its processes to apply in the defect diagnosis of mechanical components - Google Patents

Abstract

This invention is to propose both a singularity analysis method and its computational algorithm to apply in the defect diagnosis of mechanical components. By applying the singularity analysis to the vibration impulse in time domain, a quantitative feature could be derived from calculating the singularity exponents of the demodulated signal and would become more explicit in defect diagnosis. The quantitative feature would be capable of applying in an automatic diagnosis system to judge the running condition of mechanical systems.

Description

^ 238926 发明 Description of the invention: [Technical field to which the invention belongs] The present invention relates to a singularity diagnosis processing and execution method of vibration signals, which mainly performs high-frequency demodulation by taking a time-domain vibration signal to obtain the pulse knock. The analysis value of the hit point's liability is based on the pulse vibration that can directly determine whether it is mechanical damage, and a numerical form can be used to indicate the operating status of the mechanical system. This will make it easier for the computer to perform judgments to meet the mechanical damage detection automation. demand. '[Previous technology] The scale of the mechanical system components is the initial damage of the thief'. You can send the final message when the failure occurs, and adjust and arrange for maintenance by the industrial manufacturing. Because the initial damage of the mechanical system components will cause the system to generate knocks, and due to the obstruction of the system, most of the moving components are rotating components. If damage occurs to such components, periodic knocks will occur, so the mechanical components are diagnosed. The operating condition lies in the occurrence of the vibration signal. The analysis process can be generally divided into three stages: data acquisition, signal processing, and spectrum analysis. First use a vibration sensor (such as a displacement σ ten speed gauge or an acceleration gauge) to convert the physical quantity of vibration into a voltage form. After the voltage is moderately amplified by an amplifier, the voltage is input into a computer through an analog-to-digital conversion interface for digital signals. Processing to capture important information of vibration signals, and finally perform spectrum analysis to obtain vibration spectrum diagrams to show the frequency characteristics of vibration signals, and to judge the damage of mechanical system components through the frequency distribution and pattern of the frequency spectrum 1238926 (pattern) . However, due to the relatively brittle noise in the vibration signal penetration of the mechanical system, if the component is damaged slightly, the energy of the vibration signal generated is small, so it will be covered by the noise and difficult to detect. The energy of the vibration signal generated by it will become larger, and it will be obvious when it is larger than the vibration energy of noise. However, at this time, the damage of the components has become serious. Therefore, the mechanical system may stop running at any time due to this. This phenomenon is a difficulty faced by general spectrum analyzers when analyzing mechanical vibration signals, and is also a major deficiency in the failure to exert the effect of damage diagnosis and early warning in actual use. For the above problems, the most commonly used signal processing method is the high frequency resonance technique to improve the accuracy of mechanical diagnosis. When analyzing the phenomenon caused by the vibration caused by the damage of the component and the resonance of the mechanical system, the vibration signal of the damage of the component of the mechanical system can be expressed as v (t) = d (t) · s⑴ + n (t ) Where d⑴ is a periodic tapping sequence signal function generated by component damage, and its frequency is generally about several hundred Hz; s⑴ is a time function of the resonance of a mechanical system, and its frequency is generally about several kHz, even more than a dozen kHz; n⑴ It is a time function of noise. Generally, its frequency energy is distributed below 2 kHz (as shown in the first figure, the tap signal can be expressed as an exponential decay function form). When the product of d (t) and s (t) will show the modulation phenomenon of the signal, if the resonance frequency of the mechanical system is simplified, it can be expressed as the phenomenon shown in the second figure. The damaged vibration signal of hundreds of Hz is modulated to several kHz. Therefore, if the 1238926 mechanical vibration signal K 0 can be used to filter out the noise n (t) with a band-pass filter (select a frequency band above 2 kH z), only the modulation signal can be captured, and the noise generated by the noise can be greatly reduced. Signal interference; then demodulate this modulation signal to restore the impact signal of component damage. Traditionally, the methods for completing the demodulation analysis of audio frequency can be divided into two methods: hardware and software. The method of hardware demodulation is to pass the captured mechanical vibration signal through a band-pass filter, and then pass this signal through a low-pass filter of lkHz.

The demodulated signal can be obtained. The band-pass filtering and low-pass filtering used are both implemented in hardware; however, the demodulated signal obtained by this method will have a considerable degree of distortion. As for the software demodulation method, the captured mechanical vibration signal is input into the computer by analog to digital method, and then the captured signal is band-pass filtered by digital filtering, wave method or fast Fourier transform, and then the band is filtered. The signal after pass filtering is converted by Hilbert to obtain the final demodulated signal. After the demodulation signal is obtained by the above two demodulation methods, a frequency analysis method is used to analyze whether the vibration frequency contains the characteristic frequency of the damage of the mechanical component. Therefore, the damage of the mechanical component is judged. Although the mechanically damaged components can be accurately judged through the vibration spectrum, the interpretation of the frequency spectrum usually requires professionals to perform. For the large number of machinery in the industrial large factory, professionals with the same number of covers will be required to perform the mechanical damage. Analysis and interpretation, this will indirectly increase production costs. Because of the above-mentioned shortcomings, the inventor used the "signal processing and execution method for the diagnosis of the operating status of mechanical system components" on July 7, 1992. 7 == Case _ Please (listed as the 9th ), A kind of mechanical system element H4 method, including 胄 ·, clear, demodulation analysis function of the signal processing side of the brother ... h ^ fc yfw (0 jnt where: / c is the center frequency of the bandpass band; Nine is the bandwidth of the bandpass band; is a proportional parameter that can be used to adjust the attenuation slope of the bandpass band (Scaattenuation); and the demodulation signal can be expressed as the absolute value of v⑴ and U convolution (clear. Iuti〇n) , That is, dagger, / c, /,)-L v (r) \ / c, 4 (ί a r) d / r. And a signal processing and execution method for the diagnosis of the operating status of mechanical system components, including: ha, fc, fw it) -e ^) \ eilz {fcJY) t ^ 1η {ί ^ Ί:) χ where: χ is a bandpass The center frequency of the frequency band; / νν is the bandwidth of the bandpass band; 1238926 «is a proportional parameter that can be used to adjust the attenuation slope of the bandpass band (will e attenuation) i, and the demodulation signal can be expressed as v⑴ and u) .Iuti〇n) absolute value, that is

e-Jc Jw W 1: 1 lj (^) haJcJw (t ~ T) dT The above theoretical analysis is implemented in a computer system with the following algorithm. · The sampling time τ, parameter α, See the range of / w and center frequency / c, then the demodulation function with a waveform function length of 2 kt can be expressed as, "Magic =" _ / 苎) V · 2 Winter >, (/ c + quad) 'j π kT} where Α: (_ Κ = ^ = Κ) is the position of a point in the demodulation analysis function graph; take equal frequency intervals for the center frequency / c range, that is, / 0, / 0 + jealousy, / 〇 + 2jealousy ， ··· ， / 〇 + takes / 'and the bandwidth tolerance is a fixed value, then the demodulation variational matrix can be expressed as Η (η 十 1) χ (2κ + ι) uK) υ—κ) ^ / 〇, / w (-K + l) ... haJ0, fw (K)-, / 〇 博 ， 九 (-K + 1) ··· \ /. Binding, person (K)

Kj ^ ndfjS ^ Kif ^ ndfJw (-K + l) · .. Ktf〇 ^ ndf f ^ 9 1238926 \ n + 1 h Eight where \ represents the demodulation analysis vector of the fixed band. For a mechanical vibration signal sequence v (m), 0 = m = M, the demodulation analysis can be expressed as Bayi abs (^ ^ κν) 3 ^ η + 1, Μ + 2Κ + 1 ^ 2 • • A abs (/ z2: • φ cup v) Len + lJ _abs (in + 1 * ν) ^

Among them, ^ indicates the demodulation signal obtained by the A: frequency band, * indicates the vector convolution operation, and abs〇 takes the absolute value of each element in the vector; finally, perform spectrum analysis on the demodulated signal. Then the three-dimensional spectrum can be expressed as A-3 (¾) n + 1, M + 2K + l ^ E2 3 (¾) • • where 4 ·) means spectrum analysis of the vector sequence. In "Signal Processing and Execution Method for Diagnosis of Mechanical System Element Operation Status", "Three-dimensional spectrum diagram of modulation signal [such as the third ~ u _ 101038926 not], there may be secrets in the selection with clutter _ on _ Selecting and presenting the vibration spectrum in a three-dimensional view will help professionals to enter the vibration spectrum to determine the occurrence of mechanical damage. Consider this—diagnosis: The lack of two-dimensional spectrograms has been improved, but the personnel's inspection and judgment are still brief. If the computer can be used to automatically report the initial status, when there is initial damage, then professionals will further confirm the damage and judge the mechanically damaged components, which will better meet the current needs of manufacturing automation and saving manufacturing costs. [Summary of the Invention]

The invention is a singularity diagnosis processing and execution method of Qian-Xian County, which mainly borrows a time-domain vibration signal, processes the signal with a demodulation analysis function, and sets a sequence attenuation rate (band attenuation frequency) of the function ( slope attenuation) to perform high-frequency demodulation separately, and obtain the maximum value of the obtained sequence of §fl number, and finally find the maximum value corresponding to the band pass frequency attenuation rate (slope attenuation) on the full logarithmic coordinates. Curve slope

Rate, which is the singularity analysis value of the pulse striking point, which uses the demodulation analysis function: ha, fc (0 jnt -e where: Λ is the center frequency of the band-pass band; 9 is the bandwidth of the band-pass band; β is a proportional parameter that can be used to adjust the attenuation rate of the band-pass band (slope 11 1238926 au__. And the demodulation signal can be expressed as absolute value of “convolution”, that is, ~~ ioo V (r ) \ / c, / y (卜 r) ☆ and there is a constant C satisfying the following formula ~ jc, / w⑺ 幺 Caa where the index α is the singularity analysis value of the vibration signal; At the maximum limit, then

L, / c, ruler (') WC / If the above formula corresponds to different scale parameters β and the maximum value is obtained, this maximum value corresponds to the slope of the curve of the scale parameter on the full logarithmic coordinates, that is, for this pulse. The singularity analysis value α of the hit point can be expressed as: ^ uW-iogU log «ι-log a2

Among them, fli and A represent two adjacent proportional parameter values; by this, when the vibration signal is caused by damage, its singularity analysis value is low; and when the vibration signal of normal machinery is analyzed, it shows a higher value Singularity analysis value. [Embodiment] In order to make the technical means, inventive features, objectives and effects of the present invention easy to understand, the following illustrations are illustrated together: 12 1238926 The present invention relates to a method and method for diagnosing and analyzing the singularity of vibration signals. By taking a time-domain vibration signal, performing signal processing with a demodulation analysis function, and setting a sequence attenuation rate (slope attenuation) of a band pass frequency to perform high-frequency demodulation respectively, the obtained sequence is demodulated gas

Do not find its maximum value, and finally find the maximum value corresponding to the slope of the curve of the bandpass frequency slope attenuation on the full logarithmic coordinates. This is the singularity analysis value of the pulse hit point. Demodulation analysis function: Kfc, fw (0 =-^ ~ β ^ \ βηπ {ί €-^ JTCt) where: / c is the center frequency of the band-pass band; long is the bandwidth of the band-pass band; (slope convolution α is a proportional parameter that can be used to adjust the attenuation rate of the band-pass band (attenuati0n). The demodulated signal can be expressed as the absolute value of V⑴ and / c’w (convolution), that is,

a, fc, fw (called {t-τ) άτ \ and there is a constant C that satisfies the following formula and makes the index 0C be the analysis value of miscellaneous strangeness; ¥ When taking the above formula, the maximum limit of person (/), Then 13 1238926 If the above formula corresponds to different proportional parameters β and find their maximum values respectively, this maximum value corresponds to the slope of the curve of the proportional parameter β on the full logarithmic coordinates, that is, the singularity analysis value of the pulse hit point , Can be expressed as: " =% ,, / inverse_ log ~ 2, Λ, nine (0 1〇g «ι -l〇ga2 when applied to the bearing singularity analysis, the center frequency / c = 9 kHz and bandwidth 4 = 2 kHz, and fll = 2-8 and β2 = 2 · 7, different singularity analysis values under normal conditions and damage conditions can be obtained; in order to realize the above theoretical analysis in In the computer system, the following implementation method will be proposed: 1. Set the sampling time τ, scale parameter α, bandwidth / w and center frequency / c based on the specifications of the computer. The length of the waveform function is 2KT. The demodulation function can be expressed as:

I π kT

e (^) \ ej2 " (fc ^) kT

Among them, moxibustion (-K = A: == K) is the position of a certain point in the demodulation analysis function graph. 2. It is a bandpass frequency. If the center frequency / c and bandwidth are tolerated, take a sequence ratio parameter A, , ..., the demodulation analysis matrix can be expressed as 14 1238926 Η (η) χ (2Κ + 1) Wk) Wk) W—K) \, / ^ (— κ + 1) ... 弋 'nine (κ) \, Λ, nine (—K + 1) ... 弋 'nine (K) W—κ + 1) .. · WK)

κ where 4 represents the demodulation analysis vector of the 〆th frequency band, and its scale parameter is, where 1 is the same as moxibustion 幺 η;

3. For a mechanical vibration signal sequence v (m), 0 = m = Μ, and a sequence of demodulation analysis can be expressed as: absA * v) abs (石 2 * v) abs (An * v) its center Represents the demodulated signal obtained by the second scale parameter%, where κ: '< η, * represents the vector convolution operation, and abs () is the absolute value of each element in its vector; 4. The maximum value of the demodulated vibration signal is: Λ, Μ + 2Κ + 1

A

15 1238926 V max (A)-x2 max (e2) input—max (〇5. Finally read _ the slope of the curve of the parameter β on the full logarithmic coordinates, the singularity analysis value of this vibration signal is: fishing 10 g « w -l〇ga% + 1 where & and W are full logarithmic coordinates, and the two should be _parameter α invite β / η + 7 adjacent two points', 6. The critical value by the mechanical system and step 5 Singularity analysis value in the operating condition of the system

The boundary value of Ss is the normal operation of the mechanical system; α <the critical value is the initial damage of the mechanical system; the setting of the "critical value" is determined by different mechanical components; to make the present invention achieve the purpose of disclosure and The technical method used by it can make: Solution, take the best measurement value, its execution method is as follows: L sampling off τ to get the secret computer frequency equipment, to measure the 6 range of the normal axis signal, you can choose T = l / 25000 seconds, the change of μ with the k solution means that the different frequency bands in the prostitute mode of the age system are selected, and the amount of vibration signal is turned, and you can choose 16 ^ 1238926. [3000, 12000 ]; Generally, the setting range is 3. The setting of the Maruno Band Pass Bandwidth and the system characteristics are [2000, 3000]; 4. The waveform length of the demodulation function can be 375 strokes, and it is 2KT. = 〇〇15 seconds; As for the proportional parameter and can be set to 108 and 1-7 respectively to adjust an appropriate attenuation slope of the bandpass frequency band; the above five parameters are selected fixed numbers when used · 6. When applied to bearing singularity analysis, take I · plane seconds, center frequency Θ kH z and frequency red = 2 Here, the length of the demodulation function waveform can take π data 'and take ㈣ and ㈣, you can get the singularity score under normal conditions and when different components are damaged (as shown in Figure 8). The eighth riding show, from the points, if you set ^ 2.Wrf7,

Prepare the bearing for the strange situation and subtract her, and record it as normal operation 丨 But: when the analysis of the bearing's heterogeneity value α is less than 1 () · 2, the bearing is damaged, and the singularity score Minus will become smaller accordingly, so it can indeed be related to the operating condition of the broken bearing. = As stated above, the embodiments of the present invention can indeed achieve the expected use of the power ^, and the specific structure disclosed, not only has not been seen in the product, please be reviewed, and granted a patent, published before the request, sincerely It has fully complied with the provisions and requirements of the Patent Law. Mai Mai's application for an invention patent is a real virtue. 17 1238926 [Brief description of the diagram] The first picture: the exponential attenuation function form represented by the percussion signal. The second picture: the diagram of the modulation from the damage diagnosis signal of hundreds of Hz to the thousands of Hz. : The result of the application of the present invention to the modulation signal of the second figure. The fourth figure. The three-dimensional spectrum chart of the normal bearing. The fifth figure: The three-dimensional spectrum chart of the roller damaged bearing. The sixth figure: The three-dimensional spectrum of the damaged outer ring bearing. Spectrum chart (II) Figure 7: Three-dimensional spectrum chart of inner ring damaged bearing (III) Figure 8: Singular analysis value of vibration signal analyzed by the present invention Table 18

Claims (1)

1238926 Patent application scope: 1. A singularity diagnosis and processing method of vibration signals, which mainly uses a time-domain vibration signal and a demodulation analysis function to perform signal processing 'and sets a sequence attenuation rate of a bandpass frequency ( slope attenuation) to perform high-frequency demodulation separately, obtain the maximum value of a sequence of demodulated signals obtained, and finally obtain the curve corresponding to the band attenuation frequency attenuation rate (slope attenuation) on the full logarithmic coordinates. Slope, which is the singularity analysis value of the impulse hit point; By this, the singularity analysis method of the pulse vibration signal is proposed using the development of the automatic mechanical diagnosis system. The time-domain vibration signal can directly determine whether it is a mechanical damage pulse vibration. A numerical form can be used to indicate the operating status of the mechanical system. This will facilitate the computer to perform judgments to meet the needs of mechanical damage detection automation and to facilitate the interpretation of the operating status of the mechanical system. ~ A method for performing the singularity analysis value of the vibration signal, including: (1) Setting the parameter value of the demodulation analysis function: setting the sampling time T, bandwidth A, and center frequency / c of the data acquisition according to the specifications and characteristics of the computer Range 'and set two appropriately selected scaling parameters 31, milk, and take the length of the waveform function as 2KT; (2) obtain the demodulation analysis matrix: the demodulation analysis matrix can be expressed as [(2) χ (2Κ + 1) , Eight, nine (-Κ) \, Λ, nine (-Κ + 1) &quot; · \, Λ, 夂 (Κ) \, / c, and (-κ) (-Κ + 1) · • person, Λ, nine (Κ) one (3) obtained the demodulation analysis signal of the mechanical vibration signal sequence &lt; melon): 19 1238926 The demodulated signal is expressed as: λ _ ei y 2, Μ + 2Κ +1 a e2 abs (&amp; * v) abs (^ 2 * v) where * represents the vector convolution operation, and abs () takes the absolute value of each element in its vector; (4) obtains the maximum value of the demodulated vibration signal The value is: χι max (^) max (e2) (5) The singularity analysis value of the vibration signal is obtained: —log xr log x2 cx—— log axAog a2 (6) The singularity analysis value is used to judge the operating status of the mechanical system For: 2 The critical value is the normal operation of the mechanical system; <The critical value is the initial damage of the mechanical system; the setting of the "critical value" is determined by different mechanical components; by this, the singularity analysis value analyzed by it It is displayed in the computer, and the preliminary condition is automatically judged. When there is preliminary damage, professionals will further confirm the damage and judge the mechanically damaged components, which will be more consistent. Meet the current needs of manufacturing automation and saving manufacturing costs. 3. The method of performing the singularity analysis value of the vibration signal as described in item 2 of the scope of the patent application, where: 20 (1) The sampling time T depends on the computer hardware equipment. For the range of general vibration signal measurement, you can choose T = l / 25000 seconds; (2) The change of the center frequency of the bandpass band of Λ means that different frequency bands in the resonance mode of the mechanical system are selected. For the range of general vibration signal measurement, you can choose [3000, 12000]; (3) The setting of the bandpass bandwidth of Λ is related to the system characteristics. Generally, the setting range is [2000, 3000]; (4) The demodulation function waveform length can take 375 records, which is 2KTT = 0.015 seconds ; (5) As for the ratio parameter condition and must be set to 10_8 and 10_7, respectively, to adjust a proper attenuation bandpass slope; the above five parameters are selected fixed parameters when used; (6) when applied to bearings For the singularity analysis, take T = l / 25000 seconds, center frequency / c = 9 kHz and bandwidth 焱 = 2 kHz, and the demodulation function waveform length can take 375 data, and the condition = 2_8 and 52 = 2 ^, You can get the singularity under normal conditions and when different components are damaged Sex analysis value. twenty one