JP2018013345A - Abnormality diagnostic system and abnormality diagnostic method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abnormality diagnostic system and abnormality diagnostic method capable of detecting an occurrence of diversified abnormality occurring in an instrument, while suppressing increase in an arithmetic load.SOLUTION: An abnormality diagnostic system 1 includes: a vibration sensor 2 mounted on an instrument 6 as a diagnostic object; spectrum analysis means 32 for performing spectrum analysis of a detection signal obtained by the vibration sensor 2; peak value extraction means 41 for extracting a peak value of a spectrum for each frequency obtained by the spectrum analysis means 32; threshold setup means 42 for setting up a threshold with which abnormality is determined, on the basis of the peak value extracted by the peak value extraction means 41; abnormality determination means 33 that, when a spectrum analysis result obtained by the spectrum analysis means 32 exceeds the threshold in any frequency, determines that abnormality occurs in the instrument 6; and abnormality signal output means 34 that, when the abnormality determination means 33 determines that the abnormality occurs in the instrument 6, outputs an abnormal signal representing the occurrence of the abnormality.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an abnormality diagnosis system and an abnormality diagnosis method for diagnosing abnormality of a device based on an analysis result of vibration generated in the device.

  Conventionally, an abnormality diagnosis apparatus that diagnoses an abnormality of the device based on an analysis result of vibration generated in the device is known (for example, see Patent Document 1).

  The abnormality diagnosis apparatus (evaluation apparatus) described in Patent Document 1 performs an analysis process on an AD conversion unit that converts an analog signal of sound or vibration generated from mechanical equipment into a digital signal, and an output of the AD conversion unit. To generate actual measured frequency spectrum data, and to detect abnormalities in mechanical equipment depending on the presence or absence of peaks in the measured frequency spectrum data for the primary, secondary, and quaternary values of frequency components generated due to abnormalities in mechanical equipment. And an arithmetic processing means for diagnosing the presence or absence.

  Further, the abnormality diagnosis device described in Patent Document 1 is intended for diagnosing an abnormality of a rolling bearing of a mechanical facility, and includes inner and outer rings, rolling elements, a cage, and the like that constitute the rolling bearing. Diagnosis of wear and damage of the bearing is based on the vibration during driving of the rolling bearing. The presence or absence of a peak in the measured frequency spectrum data that is a criterion for abnormality is the primary value of the frequency component calculated based on the specifications of the rolling bearing, such as the pitch circle diameter of the inner and outer rings and the number of rolling elements, and the secondary value. Value and quaternary value are judged.

Japanese Patent Laid-Open No. 2003-130763

  In addition to rolling bearings, equipment such as machine tools include various components such as a cutting tool such as a drill, a motor, or a ball screw. Therefore, abnormalities may occur in components other than these rolling bearings. . Moreover, if the frequency when the abnormality occurs is calculated for all the constituent members constituting the device and it is determined whether there is an abnormality with respect to the primary value or the secondary value of the frequency component, it is excessive. Computational load is generated.

  Therefore, an object of the present invention is to provide an abnormality diagnosis system and an abnormality diagnosis method capable of detecting the occurrence of various abnormalities occurring in a device while suppressing an increase in calculation load.

  In order to achieve the above object, the present invention is an abnormality diagnosis system for diagnosing abnormality of a device by measuring vibration generated in the device to be diagnosed, the vibration sensor attached to the device, and the vibration sensor Spectrum analysis means for spectrum analysis of the detection signal obtained from the above, peak value extraction means for extracting the peak value of the spectrum for each frequency obtained by the spectrum analysis means, and for each frequency extracted by the peak value extraction means A threshold setting means for setting a threshold value for determining an abnormality based on the peak value of the spectrum, and after the threshold value is set by the threshold setting means, the spectrum analysis result obtained by the spectrum analysis means is at any frequency. An abnormality determining means for determining that an abnormality has occurred in the device when the threshold is exceeded; When said abnormality is determined to have occurred in the device, to provide a fault diagnosis system having an abnormal signal outputting means for outputting an abnormal signal indicating the occurrence of the abnormality, the by.

  In order to achieve the above object, the present invention is an abnormality diagnosis method for diagnosing abnormality of a device by measuring vibration generated in the device to be diagnosed, which is obtained from a vibration sensor attached to the device. A spectrum analysis step for spectrum analysis of the detected signal, a peak value extraction step for extracting a peak value of a spectrum for each frequency obtained in the spectrum analysis step, and a peak value for each frequency extracted in the peak value extraction step Based on the threshold setting step for setting a threshold value for determining an abnormality, and after the threshold value is set in the threshold value setting step, the spectrum analysis result of the detection signal acquired from the vibration sensor is at any frequency. An abnormality determination step for determining that an abnormality has occurred in the device when a threshold value is exceeded; When abnormality in the device is determined to have occurred in the abnormality determining step, providing an abnormality signal output step of outputting a signal indicating the occurrence of the abnormality, an abnormality diagnosis method having.

  According to the abnormality diagnosis system and the abnormality diagnosis method according to the present invention, it is possible to detect the occurrence of various abnormalities occurring in a device while suppressing an increase in calculation load.

It is a schematic block diagram which shows the abnormality diagnosis system which concerns on embodiment of this invention with the programmable controller which controls the apparatus of diagnosis object, and an apparatus. It is a flowchart which shows the specific example of the abnormality diagnosis method. (A)-(d) is the spectrum waveform which spectrum-analyzed the detection signal of the vibration sensor 2 in each cycle time of an apparatus, respectively. (A) superimposes the waveforms shown in FIGS. 3 (a) to 3 (d). (B) is a graph which shows the peak value which is the maximum value in each frequency band of the waveform superimposed in (a). (C) is a graph showing a threshold set by adding a predetermined value to each peak value in the graph shown in (b). (A) is a graph which shows a spectrum waveform in the case where it is determined that no abnormality has occurred in the device. (B) And (c) is a graph which shows a spectrum waveform when it determines with abnormality having generate | occur | produced in the apparatus.

[Embodiment]
An embodiment of the present invention will be described with reference to FIGS. In addition, although embodiment described below is shown as a suitable specific example in implementing this invention, although there are some parts which have illustrated various technical matters that are technically preferable. The technical scope of the present invention is not limited to this specific embodiment.

  FIG. 1 is a schematic configuration diagram illustrating an abnormality diagnosis system 1 according to an embodiment of the present invention, together with a device 6 to be diagnosed and a programmable controller 7 that controls the device 6. The abnormality diagnosis system 1 diagnoses an abnormality of the device 6 by measuring vibration generated in the device 6.

  The abnormality diagnosis system 1 includes a vibration sensor 2 attached to a device 6, a data logger 3 that acquires and stores a detection signal of the vibration sensor 2, and a computer 4 connected to the data logger 3. Yes. The device 6 is a machine tool that performs predetermined machining and assembly on a workpiece in a predetermined cycle time, for example, and the electric motor 61, the movable portion 62 driven by the electric motor 61, and the operation of the movable portion 62. A rolling bearing 63 and the like for smoothness are included.

  The vibration sensor 2 can detect vibration intensity (acceleration) in three directions (X direction, Y direction, and Z direction) perpendicular to each other, and outputs a detection signal corresponding to the detected vibration intensity. Moreover, the vibration sensor 2 is fixed to the electric motor 61 or the movable part 62 or the vicinity thereof by, for example, a plurality of bolts.

  The data logger 3 is connected to the vibration sensor 2 via a communication line, and receives a detection signal of the vibration sensor 2 by serial communication via the communication line. The data logger 3 includes a CPU (arithmetic processing unit) and a storage unit such as a ROM and a RAM, and the CPU executes a program stored in the storage unit, whereby the vibration data storage unit 31 and the spectrum analysis unit 32 are executed. , Function as abnormality determination means 33 and abnormality signal output means 34.

  The vibration data storage unit 31 is a unit that stores the detection signal received from the vibration sensor 2 in the storage unit. The spectrum analysis unit 32 is a unit that performs spectrum analysis on the detection signal acquired from the vibration sensor 2. More specifically, the spectrum analysis unit 32 performs FFT (Fast Fourier Transform) on the detection signal of the vibration sensor 2 stored in the storage unit by the vibration data storage unit 31 to obtain the vibration intensity for each frequency. Calculate.

  The abnormality determination means 33 is a means for determining that an abnormality has occurred in the device 6 when the spectrum analysis result obtained by the spectrum analysis means 32 exceeds a threshold set by the computer 4 described later at any frequency. is there. The abnormality signal output unit 34 is a unit that outputs an abnormality signal indicating the occurrence of the abnormality when the abnormality determination unit 33 determines that an abnormality has occurred in the device 6.

  The computer 4 is connected to the data logger 3 by, for example, a wireless LAN or a communication line, and bidirectional communication with the data logger 3 is possible. The computer 4 functions as a peak value extraction unit 41 and a threshold setting unit 42 when the CPU executes a program stored in advance on a hard disk or the like.

  The peak value extraction unit 41 extracts the peak value of the spectrum for each frequency obtained by the spectrum analysis unit 32. Here, the “peak value” is the maximum value of the vibration intensity at the frequency in the spectrum analysis result over a predetermined period. The threshold setting unit 42 sets a threshold value for determining an abnormality based on the peak value for each frequency extracted by the peak value extracting unit 41. The set threshold value is transmitted to the data logger 3, and the data logger 3 stores this threshold value.

  In the present embodiment, the threshold setting unit 42 sets a value obtained by adding a predetermined value to the peak value for each frequency extracted by the peak value extracting unit 41 as a threshold. If this predetermined value is small, erroneous detection of abnormality frequently occurs, and if it is too large, the abnormality cannot be detected even if an abnormality has occurred. Therefore, this predetermined value is set to a value that does not cause the vibration intensity to exceed the threshold value when the device 6 is normal and can reliably detect the occurrence of the abnormality when the abnormality occurs.

  Further, a display device 51 is connected to the computer 4, and the analysis result by the spectrum analysis means 32, the information of the detection signal of the vibration sensor 2 stored by the vibration data storage means 31, and the threshold setting means 42 are set. It is possible to display the information on the threshold value displayed on the display screen to the user. The user can edit the threshold value by operating the input device 52 (a pointing device such as a keyboard or a mouse) of the computer 4. When the threshold set by the threshold setting means 42 is edited by the user, the edited threshold information is transmitted to the data logger 3 and stored.

  Next, an abnormality diagnosis method in the abnormality diagnosis system 1 will be described with reference to FIG. FIG. 2 is a flowchart showing a specific example of the abnormality diagnosis method in the abnormality diagnosis system 1.

  This abnormality diagnosis method includes a preparation step that is a preparation stage of diagnosis, and a diagnosis step that diagnoses the device 6 after the preparation step is completed. The preparation step includes a spectrum analysis step S1 for spectrum analysis of the detection signal acquired from the vibration sensor 2, a peak value extraction step S2 for extracting a peak value of the spectrum for each frequency obtained in the spectrum analysis step S1, and a peak value A threshold value setting step S3 for setting a threshold value for determining an abnormality based on the peak value for each frequency extracted in the extraction step S2.

  The diagnosis step includes a spectrum analysis step S4 for analyzing the spectrum of the detection signal acquired from the vibration sensor 2, and a comparison between the spectrum analysis result analyzed in the spectrum analysis step S4 and the threshold set in the threshold setting step S3. An abnormality determination step S5 for determining whether or not an abnormality has occurred, and an abnormality signal output step S6 for outputting a signal indicating the occurrence of the abnormality when it is determined that an abnormality has occurred in the device 6 in the abnormality determination step S5. And have. In the abnormality determination step S5, it is determined that an abnormality has occurred in the device 6 when the spectrum analysis result in the spectrum analysis step S4 exceeds a threshold value at any frequency.

  In the present embodiment, the processes of spectrum analysis steps S1, S4, abnormality determination step S5, and abnormality signal output step S6 are performed by spectrum analysis means 32, abnormality determination means 33, and abnormality signal output means 34 of data logger 3, respectively. Executed. Further, the peak value extraction step S2 and the threshold value setting step S3 are executed by the peak value extraction means 41 and the threshold value setting means 42 of the computer 4, respectively. However, there is no particular limitation as to which apparatus executes the process of each step, and for example, the processes of steps S1 to S6 may be executed by one apparatus.

  Next, a specific example of the processing of the peak value extraction step S2 by the peak value extraction means 41 and the processing of the threshold value setting step S3 by the threshold value setting means 42 will be described with reference to FIGS.

  3A to 3D are spectrum waveforms obtained by performing spectrum analysis on the detection signal of the vibration sensor 2 in one cycle time of the device 6, respectively. These waveforms show the peak values of vibration intensity during one cycle time for each frequency band of 3 Hz, for example. The horizontal axis of each spectrum waveform indicates the frequency, and the range is, for example, 0 to 1.5 KHz. As shown in FIGS. 3A to 3D, the spectrum waveforms at the respective cycle times have substantially the same shape. For example, depending on the hardness of the workpiece and the degree of wear of the blade, the vibration intensity of each frequency band is gradually increased. Will vary.

  FIG. 4 (a) is a superposition of the waveforms shown in FIGS. 3 (a) to 3 (d). FIG. 4B is a graph showing a peak value which is the maximum value in each frequency band of the waveform superimposed in FIG. This graph shows the peak value of the spectrum for each frequency extracted in the peak value extraction step S2 of the procedure shown in FIG.

  FIG. 4C is a graph showing threshold values set by adding a predetermined value to each peak value in the graph shown in FIG. In FIG. 4C, a graph before adding the predetermined value (graph shown in FIG. 4B) is indicated by a two-dot chain line, and a threshold value obtained by adding the predetermined value is indicated by a solid line. The processing for calculating the threshold is performed in threshold setting step S3 of the procedure shown in FIG. The set threshold value is transmitted from the computer 4 to the data logger 3 and stored in the data logger 3.

  Each process of the preparation step (spectrum analysis step S1, peak value extraction step S2, and threshold setting step S3) is performed in a state where no abnormality occurs in the device 6, and the device 6 is processed during the preparation step. If any abnormality occurs, the process for eliminating the abnormality is performed and the information related to the detection signal of the vibration sensor 2 stored in the storage unit of the data logger 3 is erased. Then, each process of the preparation step is performed again. Run.

  In the above description, for ease of explanation, the case where the threshold value is set based on the result of spectral analysis of the detection signal of the vibration sensor 2 at four cycle times has been described. In order to prevent this, for example, it is desirable to set the threshold value based on the result of measuring the vibration over a cycle time of 1000 times or 10,000 times. When a vibration sensor 2 capable of detecting vibration intensities in three directions perpendicular to each other is used, the same diagnosis is performed for each of these three directions. Furthermore, when a plurality of vibration sensors 2 are attached to the device 6, the same diagnosis as described above is performed for each of the plurality of vibration sensors 2.

  Next, a specific example of the process of the abnormality determination step S5 performed by the abnormality determination unit 33 will be described with reference to FIGS. 5A to 5C, the threshold value is indicated by a broken line, and the spectrum intensity analyzed in the spectrum analysis step S4 is indicated by a solid line.

  FIG. 5A shows a spectrum when the spectrum intensity analyzed in the spectrum analysis step S4 is lower than the threshold value set in the threshold value setting step S3 in the entire frequency range, and it is determined that no abnormality has occurred in the device 6. It is a graph which shows a waveform. FIGS. 5B and 5C show the spectrum waveforms when the spectrum intensity analyzed in the spectrum analysis step S4 in the illustrated A part and B part exceeds the threshold value and it is determined that an abnormality has occurred in the device 6. It is a graph which shows.

  As described above, the abnormality determination unit 33 determines that an abnormality has occurred in the device 6 when the spectrum analysis result of the spectrum analysis step S4 exceeds the threshold set in the threshold setting step S3 at any frequency. Such an abnormality can occur, for example, due to wear of the rolling bearing 63, damage to the gears in the movable portion 62, or excessive wear or breakage of the cutting tool. When it is determined that an abnormality has occurred in the device 6, the abnormality signal output means 34 outputs an abnormality signal indicating the occurrence of the abnormality. Specifically, an abnormal signal is output from the data logger 3 to the programmable controller 7 by the processing of the abnormal signal output means 34.

  An alarm device 8 is connected to the programmable controller 7. The alarm device 8 notifies an operator of the occurrence of an abnormality, and is, for example, a lamp or a buzzer. The programmable controller 7 stores in advance a sequence program constructed so as to activate the alarm device 8 when an abnormal signal is received from the data logger 3. Moreover, the programmable controller 7 stops control of the apparatus 6 as needed, when an abnormal signal is received from the data logger 3. FIG.

(Operation and effect of the embodiment)
According to the embodiment described above, the peak value of the spectrum for each frequency obtained by the spectrum analyzing means is extracted, and the threshold value for determining an abnormality is automatically set based on the extracted peak value. In the diagnosis step, when the spectrum analysis result exceeds a threshold value at any frequency, it is determined that an abnormality has occurred in the device 6. For this reason, compared with the case where the peak value of a spectrum is extracted manually and a threshold value is set, the work load can be greatly reduced. Further, for example, an increase in calculation load is suppressed as compared to a case where the frequency at which an abnormality has occurred for each of the constituent members constituting the device 6 is calculated to determine the presence or absence of the abnormality. Furthermore, even when an unexpected abnormality occurs in the device 6, the abnormality can be detected. That is, it is possible to detect the occurrence of various abnormalities occurring in the device 6.

  In addition, according to the above embodiment, since a value obtained by adding a predetermined value to the extracted peak value for each frequency is set as a threshold value, it is possible to suppress erroneous detection of an abnormality and to reduce the calculation load when calculating the threshold value. It becomes possible to suppress.

(Appendix)
As described above, the abnormality diagnosis system and abnormality diagnosis method of the present invention have been described based on the embodiments. However, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the scope of the present invention. Is possible. For example, in the above-described embodiment, the case where the device 6 is a machine tool has been described. However, the present invention is not limited to this, and various devices can be diagnosed.

DESCRIPTION OF SYMBOLS 1 ... Abnormality diagnosis system 2 ... Vibration sensor 3 ... Data logger 4 ... Computer 6 ... Equipment 31 ... Vibration data storage means 32 ... Spectrum analysis means 33 ... Abnormality determination means 34 ... Abnormal signal output means 41 ... Peak value extraction means 42 ... Threshold value Setting means

In order to achieve the above object, the present invention is an abnormality diagnosis system for diagnosing abnormality of a device by measuring vibration generated in the device to be diagnosed, the vibration sensor attached to the device, and the vibration sensor Spectrum analysis means for spectrum analysis of the detection signal acquired from the above, peak value extraction means for extracting the peak value of the spectrum that is the maximum value of the vibration intensity for each frequency obtained by the spectrum analysis means over a predetermined period , Based on the peak value for each frequency extracted by the peak value extracting means, a threshold setting means for setting a threshold value for determining an abnormality, and after the threshold value is set by the threshold setting means, obtained by the spectrum analyzing means. When the obtained spectrum analysis result exceeds the threshold at any frequency, an abnormality has occurred in the device. An abnormality diagnosis system comprising: an abnormality determination unit for determining; and an abnormality signal output unit that outputs an abnormality signal indicating the occurrence of an abnormality when the abnormality determination unit determines that an abnormality has occurred in the device. .

In order to achieve the above object, the present invention is an abnormality diagnosis method for diagnosing abnormality of a device by measuring vibration generated in the device to be diagnosed, which is obtained from a vibration sensor attached to the device. A spectrum analysis step for spectrum analysis of the detected signal, a peak value extraction step for extracting a peak value of a spectrum that is a maximum value of vibration intensity for each frequency obtained in the spectrum analysis step over a predetermined period, and the peak value Based on the peak value for each frequency extracted in the extraction step, a threshold setting step for setting a threshold for determining an abnormality, and a detection signal acquired from the vibration sensor after the threshold is set in the threshold setting step When the spectrum analysis result of the frequency exceeds the threshold at any frequency, An abnormality diagnosis method comprising: an abnormality determination step that determines that an abnormality has occurred; and an abnormality signal output step that outputs a signal indicating the occurrence of the abnormality when it is determined in the abnormality determination step that an abnormality has occurred in the device. provide.

Claims (4)

An abnormality diagnosis system for diagnosing abnormality of the device by measuring vibration generated in the device to be diagnosed,
A vibration sensor attached to the device;
Spectrum analysis means for spectrum analysis of a detection signal acquired from the vibration sensor;
Peak value extraction means for extracting the peak value of the spectrum for each frequency obtained by the spectrum analysis means;
Threshold setting means for setting a threshold for determining an abnormality based on the peak value for each frequency extracted by the peak value extracting means;
After the threshold value is set by the threshold value setting unit, when the spectrum analysis result obtained by the spectrum analysis unit exceeds the threshold value at any frequency, the abnormality determination unit determines that an abnormality has occurred in the device. When,
An abnormality signal output means for outputting an abnormality signal indicating the occurrence of the abnormality when the abnormality determination means determines that an abnormality has occurred in the device;
An abnormality diagnosis system having The threshold value setting means sets, as the threshold value, a value obtained by adding a predetermined value to the peak value for each frequency extracted by the peak value extraction means;
The abnormality diagnosis system according to claim 1. An abnormality diagnosis method for diagnosing abnormality of the device by measuring vibration generated in the device to be diagnosed,
A spectral analysis step of spectrally analyzing a detection signal acquired from a vibration sensor attached to the device;
A peak value extracting step of extracting a peak value of the spectrum for each frequency obtained in the spectrum analyzing step;
A threshold setting step for setting a threshold for determining an abnormality based on the peak value for each frequency extracted in the peak value extraction step;
An abnormality that determines that an abnormality has occurred in the device when a spectrum analysis result of a detection signal acquired from the vibration sensor exceeds the threshold value at any frequency after the threshold value is set in the threshold value setting step. A determination step;
When it is determined that an abnormality has occurred in the device in the abnormality determination step, an abnormality signal output step of outputting a signal indicating the occurrence of the abnormality,
An abnormality diagnosis method comprising: In the threshold setting step, a value obtained by adding a predetermined value to the peak value for each frequency extracted in the peak value extracting step is set as the threshold.
The abnormality diagnosis method according to claim 3.

Images