JP2020060458A - Abnormality determination device - Google Patents

Abstract

To provide an inexpensive abnormality determination device capable of determining the presence or absence of an abnormality and predicting failure in a pneumatic apparatus.SOLUTION: The abnormality determination device comprises first to fourth sound sensors 13, 31, 34 and 35 for detecting sound generated in pneumatic apparatuses such as a pneumatic cylinder, a pneumatic valve and first and second silencers, and a determination unit 42 for determining the current condition by analyzing the sound detected by the first to fourth sound sensors 13, 31, 34 and 35.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an abnormality determination device that determines the presence / absence of abnormality of a pneumatic device and predicts the life of the pneumatic device by using the sound generated by the pneumatic device.

  Air leakage is one of the causes of failure of pneumatic equipment such as air cylinders and solenoid valves. By detecting the presence / absence of this air leakage, it becomes possible to judge the presence / absence of abnormality of the pneumatic equipment and to predict the replacement time (life) of the pneumatic equipment. In order to detect the air leakage of the pneumatic equipment, for example, as described in Patent Document 1, the phenomenon that the air pressure decreases due to the air leakage from the pneumatic circuit can be used.

  On the other hand, in order to determine whether or not there is an abnormality in the air cylinder, it is possible to measure the actual stroke amount and compare the stroke amount with a design value. In order to realize this, it is necessary to measure the stroke amount of the air cylinder with high accuracy. The stroke amount of the air cylinder can be measured with high accuracy by using ultrasonic waves as described in, for example, Patent Document 2.

JP, 2005-105879, A Japanese Utility Model Publication No. 59-32707

  If air pressure is used as disclosed in Patent Document 1 in determining whether there is an abnormality in the pneumatic equipment or predicting a failure, the pneumatic equipment in which the abnormality has occurred cannot be specified. The reason for this is that the entire air pressure of the pneumatic circuit is detected by the pressure sensor. Among pneumatic equipment, an air cylinder can determine whether there is an abnormality or predict a failure based on a stroke amount measured by a highly accurate measuring device as disclosed in Patent Document 2. Is. However, it is difficult to equip each air cylinder with a highly accurate measuring device due to the high cost.

  An object of the present invention is to provide an abnormality determination device which is capable of determining the presence / absence of abnormality of a pneumatic device and predicting a failure, and which is inexpensive.

  In order to achieve this object, an abnormality determination device according to the present invention includes a sound sensor that detects a sound generated in a pneumatic device, and a determination unit that analyzes the sound detected by the sound sensor and determines the current situation. It is equipped with and.

  In the abnormality determination device of the present invention, the determination unit may determine the current situation by comparing the volume of the sound detected by the sound sensor with a predetermined volume.

  In the abnormality determination device of the present invention, the volume of the sound detected by the sound sensor may be the volume of the sound in a predetermined frequency band that has passed through the bandpass filter.

  In the abnormality determination device of the present invention, the determination unit may measure a frequency component of a sound detected by the sound sensor and determine a current situation based on the frequency component.

  In the abnormality determination device of the present invention, the current situation includes the presence or absence of an abnormality, and the determination unit predetermines at least one of a sound volume and a sound quality of a current pneumatic device. Alternatively, the abnormality may be detected by comparing with at least one of the allowable range and the data of the durability test.

  The present invention, in the abnormality determination device, further includes an alarm unit for issuing an alarm, and the alarm unit issues an alarm when the sound detected by the sound sensor is determined to be abnormal by the determination unit. It may be one.

Sound is generated when air leakage occurs in pneumatic equipment. According to the present invention, the presence or absence of abnormality can be determined by detecting this sound by the sound sensor and analyzing it by the determination unit. Further, when an abnormality that causes a failure occurs in the pneumatic equipment, the operation sound changes. According to the present invention, a failure can be predicted by detecting this sound by the sound sensor and analyzing it by the determination unit. The sound sensor is inexpensive as compared with, for example, an ultrasonic transmitter used in an ultrasonic measuring device.
Therefore, it is possible to determine whether or not there is an abnormality in each pneumatic equipment and predict the service life thereof, and it is possible to provide an inexpensive abnormality determination device.

It is a block diagram which shows the structure of the abnormality determination device which concerns on this invention. It is a side view of a pneumatic cylinder. It is a side view of a pneumatic valve. It is a block diagram of a control device. It is a graph which shows the change of a sound volume. It is a graph which shows the relationship between frequency and volume. It is a graph which shows the relationship between frequency and volume.

Hereinafter, an embodiment of an abnormality determination device according to the present invention will be described in detail with reference to FIGS.
The abnormality determination device 1 shown in FIG. 1 determines whether or not there is an abnormality in the pneumatic cylinder 2 and the pneumatic valve 3 and predicts the life.
The pneumatic cylinder 2 is a double-acting air cylinder. The pneumatic valve 3 is for switching the operation of the pneumatic cylinder 2, and is composed of a 5-port type solenoid valve.

One end of the pneumatic cylinder 2 is connected to the first port 6 of the pneumatic valve 3 via the first pipe 4 and the first speed controller 5. The other end of the pneumatic cylinder 2 is connected to the second port 9 of the pneumatic valve 3 via the second pipe 7 and the second speed controller 8.
As shown in FIG. 2, the pneumatic cylinder 2 includes a cylinder body 11 and a piston rod 12 protruding from one end of the cylinder body 11. A first sound sensor 13 is attached to the cylinder body 11. The first sound sensor 13 is connected to the control device 16 via the amplifier 14 and the A / D converter 15, detects the sound generated in the pneumatic cylinder 2, and sends it to the control device 16 as a detection signal. . The configuration of the control device 16 will be described later.

  The pneumatic valve 3 includes a third port 18 connected to an air pressure source 17 and a fourth port 20 connected to a first silencer 19 in addition to the above-described first and second ports 6 and 9. , And a fifth port 22 connected to the second silencer 21. As shown in FIG. 3, the pneumatic valve 3 includes a valve body 23 and first and second solenoids 24 and 25 provided at both ends of the valve body 23. The operations of the first and second solenoids 24 and 25 are controlled by the controller 16 described later.

A second sound sensor 31 is attached to the valve body 23. The second sound sensor 31 is connected to the control device 16 via the amplifier 32 and the A / D converter 33, detects the sound generated by the pneumatic valve 3, and sends it to the control device 16 as a detection signal. .
Although not shown in detail, the first and second silencers 19 and 21 have a structure in which a silencer is filled in the housing. A third sound sensor 34 is attached to the housing of the first silencer 19. A fourth sound sensor 35 is attached to the housing of the second silencer 21. Exhaust pressure is not directly applied to the third and fourth sound sensors between the exhaust ports of the first and second silencers 19 and 21 and the third and fourth sound sensors 34 and 35. Thus, it is desirable to provide a shielding member (not shown).

The third sound sensor 34 is connected to the control device 16 via the amplifier 36 and the A / D converter 37, detects the sound generated by the first silencer 19, and outputs the detection signal to the control device 16. send.
The fourth sound sensor 35 is connected to the control device 16 via the amplifier 38 and the A / D converter 39, detects the sound generated by the second silencer 21, and outputs the detection signal to the control device 16. send.
In this embodiment, the pneumatic cylinder 2, the pneumatic valve 3, and the first and second silencers 19 and 21 correspond to the "pneumatic device" in the present invention. In the following, when expressing the sound generation source, the pneumatic cylinder 2, the pneumatic valve 3, the first and second silencers 19, 21 and the like are simply referred to as pneumatic equipment.

  As shown in FIG. 4, the control device 16 is connected to the above-described first to fourth sound sensors 13, 31, 34, 35 and the first and second solenoids 24, 25, and the solenoid valve control unit. 41, a determination unit 42, a communication unit 43, and a memory 44. Further, the control device 16 is connected to an indicator light 45 as an alarm device and is also connected to the Internet 46.

The solenoid valve control unit 41 controls the operation of the first and second solenoids 24 and 25 of the pneumatic valve 3 so that the pneumatic cylinder 2 operates at a predetermined operation timing.
The determination unit 42 includes a volume determination unit 51, a sound quality determination unit 52, and an alarm unit 53, and analyzes the sounds detected by the first to fourth sound sensors 13, 31, 34, 35 to determine the current state. It has a function to judge the situation. The "current situation" here is the presence or absence of an abnormality and the life. Although details will be described later, the determination unit 42 according to this embodiment has a function of determining whether or not there is an abnormality in the pneumatic equipment described above, a function of predicting a life, and a function of issuing an alarm. Although the details will be described later, the determination unit 42 sets at least one of the sound volume and sound quality of the current pneumatic device as at least one of a predetermined allowable range and durability test data. Compare and detect anomalies.

  The sound volume determination unit 51 is configured by using a so-called sound level meter (not shown), and analyzes sound with a general microcomputer {CPU (Central Processing Unit)}. The sound volume determination unit 51 according to this embodiment compares the sound volume of the sounds detected by the first to fourth sound sensors 13, 31, 34, and 35 with a predetermined sound volume to determine whether there is an abnormality or not. Predict lifespan. As shown in FIG. 5, whether or not the pneumatic equipment is normal is determined by the predetermined maximum value A of the sound volume detected by the first to fourth sound sensors 13, 31, 34, and 35. It can be determined by whether or not the sound volume is higher than the sound volume. In addition, when the volume of the current sound that is actually generated by the pneumatic equipment is higher than the volume at the normal time or the volume for the predetermined determination or the volume at the previous sound detection, in other words, the volume is predetermined. If the allowable range is exceeded, it is detected as "abnormal". When such an abnormality occurs, it means that an unexpected situation has occurred.

In order to predict the life of the pneumatic device using the sound volume, it is possible to compare the sound volume when the pneumatic device reaches the replacement time (when it reaches the end of its life) with the current sound volume. . The sound volume data when the replacement time is reached can be stored in the memory 44 of the control device 16 by performing a durability test, detecting the sound data in advance, and using the sound sensor. Therefore, when the current sound volume of the pneumatic equipment that has not reached the replacement time has reached the sound volume of the replacement time, it is determined that there is an abnormality and the life has been reached.
As shown in FIGS. 6A to 6C, the sound volume used by the sound volume determination unit 51 to determine whether there is an abnormality is the sound volume of a predetermined frequency band that has passed through the bandpass filter. Good.

In FIG. 6A, the frequency components of the sound that has passed through the bandpass filter that passes only the sound in the low frequency band are shown by solid lines, and the other frequency components are shown by broken lines.
In FIG. 6B, the frequency components of the sound that has passed through the bandpass filter that passes only the sound in the middle frequency band are shown by solid lines, and the other frequency components are shown by broken lines.
In FIG. 6C, the frequency components of the sound that has passed through the bandpass filter that passes only the sound in the high frequency band are shown by solid lines, and the other frequency components are shown by broken lines.

The sound quality determination unit 52 is configured by using a so-called FFT (Fast Fourier Transform) analyzer (not shown) or a spectrum analyzer (not shown), and has a high-performance CPU and DSP (Digital Signal Processing) processor. ).
The sound quality determination unit 52 measures the frequency components of the sounds detected by the first to fourth sound sensors 13, 31, 34, 35, and based on these frequency components, the current situation, that is, the abnormality of the pneumatic equipment described above. To determine the presence or absence of, and predict the life.

  In order to determine the presence or absence of abnormality using sound quality, the frequency components of the sounds detected by the first to fourth sound sensors 13, 31, 34, 35 (sounds generated by the current pneumatic equipment) are measured. Then, this frequency component is compared with the normal frequency component. In detail, the frequency component of the current sound that is actually generated in the pneumatic equipment is compared with the frequency component of the sound at the normal time or the sound for the predetermined judgment and the frequency component of the sound at the previous detection. If it exceeds the predetermined allowable range, it is detected as “abnormal”. When such an abnormality occurs, it means that an unexpected situation has occurred. That is, the current waveform of the pneumatic device sound (see FIG. 7) is compared with the waveform of the normal pneumatic device sound (not shown), and the current waveform changes compared with the normal waveform. If yes, it is determined to be abnormal.

To predict the life using sound quality, a durability test of pneumatic equipment is performed in advance. Then, FFT analysis is performed on the sound generated by the pneumatic equipment for each test operation of the durability test, and the characteristics of the change in the sound quality are captured. The analysis result of the FFT analysis for each test operation is recorded in the memory 44.
The life prediction is performed by comparing the frequency component of the sound obtained by performing the FFT analysis on the current sound with the frequency component of the sound obtained by performing the FFT analysis for each test operation. That is, since the number of test operations having a frequency component close to the current frequency component of the sound corresponds to the actual number of test operations of the current pneumatic device, the life of the pneumatic device can be predicted. If it is predicted that the pneumatic equipment that has not reached the replacement time has reached the end of its life, it can be determined to be abnormal.

In predicting the life, the sound volume for each frequency band for each test operation is obtained from the FFT analysis result of the sound for each test operation obtained in the durability test, and this sound volume is as shown in FIGS. 6 (A) to (C). It can be performed by comparing the volume of each current frequency band. In this case, the service life can be predicted for each band by sequentially obtaining the maximum volume in the low range, the maximum volume in the middle range, and the maximum volume in the high range. By adopting this prediction method, it becomes unnecessary to perform FFT analysis other than the durability test.
The operation of predicting the life of the pneumatic device by using the sound quality can be performed not only in real time at all times but also periodically after a predetermined time.

The alarm unit 53 issues an alarm when the determination unit 42 determines that the sounds detected by the first to fourth sound sensors 13, 31, 34, and 35 are abnormal. The alarm is issued by turning on the indicator lamp 45 (see FIG. 1).
The communication unit 43 is connected to the remote monitoring device 61 via the Internet 46, and sends the abnormality determination result and the life data to the remote monitoring device 61.

In the abnormality determination device 1 configured as described above, the sounds detected by the first to fourth sound sensors 13, 31, 34, and 35 are analyzed by the determination unit 42 of the control device 16 so that the pneumatic device The presence or absence of abnormality is determined and the life of pneumatic equipment is predicted.
When the pneumatic cylinder 2 emits an abnormal sound having a volume higher than that in the normal state, the volume of the sound of the pneumatic cylinder 2 detected by the first sound sensor 13 becomes larger than that in the normal state. Is determined to be abnormal. The alarm unit 53 turns on the indicator lamp 45 based on the determination result.

If an abnormal sound is generated during the stroke of the pneumatic cylinder 2, it can be determined that the sliding sound is being generated due to the “galling” of the piston (not shown) and the piston rod 12.
When the abnormal sound is generated at the stroke end of the pneumatic cylinder 2, it can be determined that the cushion abnormality is generated based on the volume level.
If an abnormal noise is generated while the pneumatic cylinder 2 is stopped, it can be determined that a seal member (not shown) in the pneumatic cylinder 2 is damaged and air is leaking.

If the second sound sensor 31 cannot detect sound when the pneumatic valve 3 is performing the switching operation, it is determined that the first and second solenoids 24 and 25 and the power supply system cable are disconnected. Can be determined.
When the sound detected by the second sound sensor 31 is low (volume is low), it can be determined that the operation of the pneumatic valve 3 is heavy (bad operation).
When the sound detected by the second sound sensor 31 is loud (the volume is large), it can be determined that the pneumatic valve 3 operates lightly (smoothly operates).
When the second sound sensor 31 detects a continuous sound, it can be determined that the air is leaking.

When the volume of the sound (exhaust sound) detected by the third sound sensor 34 or the fourth sound sensor 35 when the pneumatic cylinder 2 and the pneumatic valve 3 are stopped is higher than normal, the pneumatic cylinder 2 or It can be determined that the pneumatic valve 3 has internal leakage.
The first to fourth sound sensors 13, 31, 34, 35 are inexpensive as compared with, for example, an ultrasonic transmitter used in an ultrasonic measuring device.

  Therefore, according to this embodiment, it is possible to provide an inexpensive abnormality determination device capable of determining the presence / absence of abnormality of each pneumatic device and predicting the life thereof.

  The determination unit 42 according to this embodiment compares the volume of the sounds detected by the first to fourth sound sensors 13, 31, 34, and 35 with a predetermined volume to determine the current situation. Have 51. Therefore, for example, if exhaust noise is generated during stoppage, it can be determined that internal leakage has occurred, so that it is possible to realize an abnormality determination device that can easily determine whether or not there is an abnormality.

  In this embodiment, presence / absence of abnormality is determined based on the volume of the sound in the predetermined frequency band that has passed through the bandpass filter among the sounds detected by the first to fourth sound sensors 13, 31, 34, and 35. When making a determination or predicting the life, it is possible to specify a location where an abnormality has occurred or a location where the life is short. For example, when the volume in the high frequency range is large, it is considered that the main place where the sound is generated is the metal part, so it can be predicted that an abnormality has occurred in the metal part and the life of that part is shortened.

The determination unit 42 according to this embodiment measures the frequency components of the sounds detected by the first to fourth sound sensors 13, 31, 34, and 35, and determines the current situation based on the frequency components. It has a determination unit 52.
For this reason, it is possible to perform advanced sound analysis, and it is easy to capture the characteristics of sound related to air leakage and life. Further, the noise around the pneumatic equipment (noise) and the sound generated by the pneumatic equipment can be easily discriminated from each other, and therefore the reliability of the determination result is high.

The abnormality determination device 1 according to this embodiment includes an alarm unit 53 that issues an alarm. The alarm unit 53 issues an alarm when the sound detected by the first to fourth sound sensors 13, 31, 34, 35 is determined to be abnormal by the determination unit 42.
For this reason, it is possible to reliably notify the operator of the occurrence of an abnormality, and it is possible to perform repair or replacement before a serious failure occurs.

  The determination unit 42 shown in the above-described embodiment includes a volume determination unit 51 and a sound quality determination unit 52. However, the present invention is not limited to such a limitation. The abnormality determination device 1 according to the present invention can be realized even when only one of the volume determination unit 51 and the sound quality determination unit 52 is provided in the determination unit 42.

  DESCRIPTION OF SYMBOLS 1 ... Abnormality determination device, 2 ... Pneumatic cylinder (pneumatic device), 3 ... Pneumatic valve (pneumatic device), 13 ... 1st sound sensor, 19 ... 1st silencer (pneumatic device), 21 ... 2nd silencer ( Pneumatic equipment), 31 ... Second sound sensor, 34 ... Third sound sensor, 35 ... Fourth sound sensor, 42 ... Judgment unit, 51 ... Volume judgment unit, 52 ... Sound quality judgment unit, 53 ... Warning unit.

Claims (6)

A sound sensor that detects the sound generated by pneumatic equipment,
An abnormality determination device, comprising: a determination unit that analyzes the sound detected by the sound sensor and determines the current situation. The abnormality determination device according to claim 1,
The abnormality determination device, wherein the determination unit determines the current situation by comparing the volume of the sound detected by the sound sensor with a predetermined volume. The abnormality determination device according to claim 2,
The abnormality determination device, wherein the volume of the sound detected by the sound sensor is the volume of the sound in a predetermined frequency band that has passed through the bandpass filter. The abnormality determination device according to claim 1,
The abnormality determination device, wherein the determination unit measures a frequency component of a sound detected by the sound sensor and determines a current situation based on the frequency component. In the abnormality determination device according to claim 1,
The current situation includes the presence or absence of abnormality,
The determination unit detects an abnormality by comparing at least one of the sound volume and sound quality of the current pneumatic device with at least one of a predetermined allowable range and durability test data. An abnormality determination device characterized in that The abnormality determination device according to any one of claims 1 to 5,
Furthermore, an alarm unit for issuing an alarm is provided,
The abnormality determination device, wherein the alarm unit issues an alarm when the sound detected by the sound sensor is determined to be abnormal by the determination unit.

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