JPS6195218A - Apparatus for discriminating abnormally of machine operation sound - Google Patents

Abstract

PURPOSE:To make it possible to certainly discriminate different sound intermittently generated in machine operation sound, by separating machine operation sound into signals within a predetermined frequency band and detecting the average level and peak level of the separated signals. CONSTITUTION:The operation sound of an engine 1, generated when the engine 1 is set to an idling state, is detected by a detector 2 and inputted to a frequency analyser 4 through a charge amplifier 3. Separated signals within a predetermined frequency band are inputted to averaging circuits 15, 16 through a both-wave rectifier 11, an average value detector 12, a hearing sense corrector 13 and a peak detector 14. A different sound discrimination part 30 takes in the peak value and average value of each channel through an A/D converter 20 to operate average peak value data and average value data. Thereafter, an intermittent different sound factor and a continuous different sound factor operated at every channel are compared with threshold values on the basis of these data to perform the abnormality judgement of intermittent sound and continuous sound.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for determining abnormalities in mechanical operating sounds such as engine rotation noise, and in particular, it is capable of reliably identifying intermittent abnormal noises!
The present invention relates to an abnormality determination device for mechanical operation sounds that can detect abnormalities in mechanical operation sounds.

[Prior Art] Conventionally, there is a device as shown in FIG.
No. 118, etc.).

In the figure, 1. 2 is a detector such as a microphone or a vibration pickup for detecting the operating sound of the engine 1, and 3 is for amplifying the detection signal from the detector 2. When the engine 1 is operated, the charge amplifier 3 outputs a signal containing various frequency components corresponding to so-called engine rotation noise. 4 is a frequency analyzer, and this frequency analyzer 4 is, for example, 250Hz, 500H2.

lK1-1z, 2KHz, 4KHz,
Bandpass filters 4a, 4b, 4c each have a one-octave configuration with a center frequency of 8KHz.
, 4d.

4e and 4f, and the charge amplifier 3
The detector signal from the detector 2 is input to each of the band pass filters 4a to 4f. 5a to 5f are averaging circuits that average the signal waveforms of the respective frequency bands output from the bandpass filters 4a to 4'' of the frequency analyzer 4 and convert them into DC voltage levels, and 6a to 6f are meter relays. Yes, each meter relay 6a
DC flow value voltages corresponding to the abnormal signal levels of each frequency band are set for 6C to 6C. And each averaging circuit 5
When each voltage level output from a to 5C is below the threshold voltage set to each meter relay 6a to 6t, the normal lamps of the platform indicators 7a to 7f are lit, while the normal lamps from each of the averaging circuits 5a to 5f are lit. When each voltage level exceeds each fi (In voltage), the abnormality lamps of the platform indicators 7a to 7r are turned on.

Machine made like the one above! In the noise discrimination device, when the engine 1 is generating an abnormal noise, the voltage level obtained by averaging the signal waveform of the band containing each frequency component that makes up the abnormal noise becomes high. The abnormality lamp on the display lights up for the signal that has passed through the frequency band bandpass filter. Therefore, by checking the lighting lamp of this indicator, it is possible to determine whether the engine 1 is generating abnormal noise.

[Problems to be Solved by the Invention] However, after the mechanical operating sound detected as described above is separated into signals in a predetermined frequency band by the frequency analyzer 4, each separated signal is simply averaged. If the occurrence of abnormal noise is determined based on the level, it may not be possible to determine abnormal noise that occurs intermittently.

This is because in the case of intermittent abnormal noises, the signal level of the frequency band containing the frequency components that make up the abnormal noises becomes intermittently prominent, but when such signal waveforms are averaged, This is due to the fact that the averaging level is not necessarily higher (B value than Bell).

[Means for Solving the Problems] The present invention has been made in view of the above-mentioned problems, and is an abnormality determination method for machine operation sounds that makes it possible to reliably identify abnormal noises that occur intermittently in machine operation sounds. To achieve this objective, the present invention aims to provide a
In a device that separates the detection signal from a detector that detects mechanical operating sound into signals in a predetermined frequency band, and determines abnormalities in the mechanical operating sound based on each separated signal, each separated signal average level detection means for detecting the average signal level of the signal; peak level detection means for detecting the peak signal level based on a particularly prominent waveform of each of the separated signals; and the average level detection means and peak level detection means. and discriminating means for discriminating an abnormality in the mechanically generated PIJ sound based on the signal levels from the above.

[Embodiments of the invention] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing an example of an abnormality determination device for substitute machine operation noise according to the present invention.

In the figure, a detector 2 that detects the operating sound of an engine 1, which is the machine to be measured, and a charge amplifier 3 that amplifies the detection signal from the detector 2 are the same as those of the conventional device shown in FIG. Furthermore, the frequency analyzer 4 having one-octave bandpass filters 4a to 4f is also similar to the conventional device, and has the following characteristics:1. Detector 2 via charge amplifier 3
Detection signals from the band pass filters 4a to 4f are input to each of the band pass filters 4a to 4f.

11c is a double-wave rectifier that double-wave rectifies the frequency signal that has passed through the band-pass filter 4C, and 12c is a double-wave rectifier 11c.
13C is an audibility corrector that audibly corrects the output signal from the average 1n detector 12c, and 14C is an output signal waveform from the audibility corrector 13c. a peak detector 150 for detecting a particularly prominent signal voltage value of the peak detector 14;
It is an averaging @ path that determines the average voltage value of each signal voltage value detected by c. Further, 16C is an averaging circuit that averages (converts into a DC voltage value) the output signal waveform from the auditory sense corrector 13c. It averages the levels.

In addition, a double wave rectifier 11C1 following the bandpass filter 4C
A signal processing system composed of an average value detector 12C1, a hearing corrector 13C, a peak detector 14C1, and an averaging circuit 150116C is also provided for each of the other bandpass filters.

Reference numeral 20 denotes the output voltage level from each signal processing system channel following each bandpass filter 4a to 4f, specifically the averaging circuit (15c, 1) in each channel.
Output 1 from 6c) is an A/D converter that A/D converts the voltage level, and 30 is a microcontroller that determines the occurrence of abnormal noise based on the output monitor from each channel via the A/D converter 20. This is an abnormal sound discriminator made up of a computer, etc. The results of the discrimination by the abnormal sound discrimination section 30 are output to the printer 31 and are also displayed on the CRT display device 32.

Here, the abnormal sound discrimination unit 30 collects peak value data from the averaging circuit (150) in each channel and the averaging circuit (150).
160) is sampled a preset number of times at a predetermined period and averaged, respectively, to calculate average peak value data P and average average value data 8. Then, based on the average peak value data P and the average average value data A, the intermittent abnormal noise factor N
Fd is calculated according to NFd - (P - A) / A ... (1), while continuous noise factor NFr is calculated as NFr - (AxlG) / (P - A) (2>1°
r′1iLt, ′″f)814″Vyp99NFd
, ,.

NFr is predetermined 1llil (determined experimentally)
If the value exceeds 1, it is determined whether various kinds of abnormal noises (intermittent or continuous) are occurring.

Next, the specific operation will be explained.

Assume that when the engine 1 is in a fitting state, the engine operation is accompanied by intermittent abnormal noises.

The frequency components corresponding to the engine operating sound are separated by the frequency analyzer 4 as signals of each frequency band, and the separated signals are processed by each channel,
The peak value and average value of the separated signals are output from each of the averaging circuits (15C) and (16c). At this time, the output signal from each average value detection circuit (12c) is passed through band pass filters 4d to 4f (2KHz,
For example, as shown in FIG. 2, a signal transmitted via a frequency of 4 KHz or 8 Kllz has a particularly prominent waveform corresponding to the intermittent nature of the intermittent abnormal noise. Then, in the peak value detector (14c), particularly outstanding signal levels Vp (1), Vp (2), "...
・ is detected, and the averaging circuit (15C) detects the detected values vp (1), Vp (
2) Average the values and output the average value.

On the other hand, each averaging circuit (16c) averages the signal waveform as shown in FIG. 2 in the same manner as in the prior art and outputs a constant voltage value (average value).

In the process in which the signals of each frequency band separated by the frequency analyzer 4 are processed by each channel as described above, the abnormal sound discriminator 30 operates according to the flowcharts shown in FIGS. 3 and 4. The flow shown in FIG. 3 is the main flow O-, and the flow shown in FIG. 4 is a subroutine corresponding to the data sample shown in FIG.

The output values from the averaging circuits (15c) and (160) of each channel, that is, the peak value and the average value, are sent to the A/D converter 2.
Sample through 0. Specifically, as shown in Fig. 4, the registers that store data from each channel are reset, and the peak value and average value are input and specified for each channel. Import as data. Then, when the data acquisition is completed a preset number of times for all channels, the subroutine returns to the main flow), and the average peak value data P is calculated from the sampled peak value, and the sampled average value is The average average value data Δ is calculated from. Then, based on these average peak value data P and average average value data 8, the above-mentioned (1) and (2)
) An intermittent abnormal noise factor NFd and a continuous abnormal noise factor NFr are calculated according to the formula.

As mentioned above, 1gi continuous noise factor N for each channel
When Fd and the continuous noise factor NFr are calculated, the intermittent noise factor NFd is compared with a predetermined threshold value for each channel, and if the factor value exceeds the threshold value, the intermittent noise abnormality is determined. On the other hand, if the factor value is equal to or less than the threshold value, the intermittent sound is determined to be normal. After the above-described determination of intermittent abnormal noise, the continuous abnormal noise factor Nll' is compared with another predetermined 1 Jla, and if the factor value exceeds the threshold value, continuous V and sound abnormality determination is performed,
If the factor value is less than or equal to the threshold value, the continuous sound is determined to be normal in step 11.

When the determination of the Vji continuous abnormal noise and the continuous abnormal noise is completed in this way, the determination result is printed out on the printer device 31 and displayed on the CRT display device 32.

As described above, according to this embodiment, the peak value (average peak value data) of each signal separated by the frequency analyzer 4
Based on the ratio of the difference between and the average 1m (average average value data) and the average value (see formulas (1) and (2) above)
Each abnormal noise (intermittent, continuous) factor is calculated and engine operating noise abnormalities are determined based on these abnormal noise factors, so intermittent abnormal noises where the difference between the peak value and the average value is large can be reliably determined. You will be able to do it.

Furthermore, since the ratio between the difference between the peak value and the average value and the average value does not change greatly even if the detection level from the detector 2 changes, the installation state of the detector 2 to the machine to be measured 1 or the The influence of changes in the detection system over time on abnormal noise determination results is extremely reduced.

In this embodiment, abnormality determination is also performed for continuous abnormal noises based on the ratio between the difference between the peak value and the average value and the average value, but in realizing the actual device,
Regarding continuous abnormal sounds, abnormality determination may be made based only on the average value as in the conventional case.

Also, an averaging circuit (150) not shown in FIG.

The average value output in 16C) is not just an average,
Various known average output values may be obtained. Further, the same applies to the average value of the input data (peak value, average value) in the abnormal sound discrimination section 30.

[Effect of application] As explained above, according to the present invention, a signal from a detector that detects mechanical operating noise is separated into signals in a predetermined frequency band, and the average signal level of the separated signals is calculated. Since the abnormality of the mechanical operation sound is determined based on the particularly prominent peak level of the separated signal waveform,
It is now possible to reliably identify abnormal noises that occur intermittently,
As a result, machine abnormality analysis based on the abnormal noise determination result can be realized with higher accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of an abnormality determination device for mechanical operation noise according to the present invention, FIG. 2 is a waveform diagram showing an example of the output signal waveform of the average value detector in FIG. 1, and FIGS. FIG. 4 is a flowchart showing the operation of the abnormal sound discriminating section in FIG. 1, and FIG. 5 is a block diagram showing an example of a conventional mechanical #JJ sound abnormality discriminating device. 1...Engine 2...Detector 3...Charge amplifier 4...Frequency analyzer 11C...Double wave rectifier 12C...Average value detector 13C...Hearing compensator 14c... Peak value detectors 15c, 16c...Averaging circuit 20...A/'D converter 30...Abnormal noise discriminator 31...Printer device

Claims (1)

[Claims] In a device that separates the detection signal from a detector that detects mechanical operating sound into signals in a predetermined frequency band, and determines an abnormality in the mechanical operating sound based on each separated signal, each separated signal an average level detection means for detecting an average signal level of the signal, a peak level detection means for detecting a peak signal level based on a particularly prominent waveform of each of the separated signals, and from the average level detection means and the peak level detection means. and a discriminating means for determining an abnormality in the mechanical operating sound based on each signal level of the mechanical operating sound.