JP2020022260A - Machine abnormality prediction device - Google Patents

Abstract

To detect abnormality of a machinery before production operation.SOLUTION: A machine abnormality prediction device 1 is provided with: an excitation torque command generation section 10 for generating an excitation torque command by adding a torque command and an excitation command for exciting the torque command together; a motor control section 20 for controlling a motor on the basis of the excitation torque command; a frequency analysis section 40 for frequency-analyzing a vibration of a machinery 3 connected to the motor 2; a resonance point data acquiring section 30 for acquiring resonance point data that shows a resonance point of the machinery 3 using the result of the excitation command and the frequency analysis; and an abnormality determination section 50 for determining whether or not the machinery 3 has an abnormality from the resonance point data.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a machine abnormality prediction device that predicts an abnormality of a mechanical device.

  Techniques for detecting an abnormality of a mechanical device include, for example, a plurality of vibration frequency components and vibration amplitude peaks based on time-series waveform data of a torque command output from a speed control unit for a mechanical device whose speed is controlled by an electric motor. There is known a technology for diagnosing a machine abnormality by detecting a value (for example, see Patent Document 1). In addition, a technology for detecting an abnormality in a mechanical device by comparing a current flowing in a motor driving a mechanical device with an abnormal current value set in advance, and a driving frequency of the electric motor and an abnormal frequency value set in advance, respectively, has been developed. It is known (for example, see Patent Document 2).

JP 2010-166686 A JP 2007-288829 A

  However, none of the methods disclosed in the prior art documents can detect an abnormality of the mechanical device unless the mechanical device is operated (production operation) by speed control.

  An object of the present invention, which has been made in view of such circumstances, is to provide a machine abnormality prediction device that can predict an abnormality of a mechanical device before the production operation of the mechanical device.

  In order to solve the above-mentioned problem, a mechanical abnormality prediction device according to the present invention provides a vibration torque that generates a vibration torque command by adding a torque command and a vibration command for vibrating the torque command. A command generation unit, a motor control unit that controls the motor based on the vibration torque command, a frequency analysis unit that performs frequency analysis of vibration of a mechanical device connected to the motor, the vibration command, and the frequency A resonance point data obtaining unit that obtains resonance point data indicating a resonance point of the mechanical device using the analysis result, and an abnormality determination that determines whether the mechanical device has an abnormality from the resonance point data. And a unit.

  Further, in the machine abnormality prediction device according to the present invention, the resonance point data acquisition unit obtains a frequency transfer function from the frequency spectrum of the vibration command and the frequency spectrum indicating the result of the frequency analysis, and the frequency transfer function And acquiring the resonance point data based on the resonance point data.

  Further, in the machine abnormality prediction device according to the present invention, the abnormality determination unit compares the resonance point data acquired by the resonance point data acquisition unit with the resonance point data of the mechanical device in a normal state measured in advance. By doing so, it is determined whether or not there is an abnormality in the mechanical device.

  Advantageous Effects of Invention According to the present invention, it is possible to predict an abnormality of a mechanical device before the production operation of the mechanical device.

It is a block diagram showing the example of composition of the machine abnormality prediction device concerning one embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration example of a machine abnormality prediction device according to an embodiment of the present invention. The machine abnormality prediction device 1 illustrated in FIG. 1 includes a vibration torque command generation unit 10, a motor control unit 20, a resonance point data acquisition unit 30, a frequency analysis unit 40, an abnormality determination unit 50, and an alarm unit 60. Is provided.

  The excitation torque command generator 10 varies the frequency of the torque command in order to find the resonance frequency of the mechanical device 3. Specifically, the vibration torque command generation unit 10 includes a torque command output unit 11, a vibration command output unit 12, and an addition unit 13, and generates a torque command and a torque command for vibrating the torque command. A vibration torque command is generated by adding the vibration command.

  When performing torque control on the mechanical device 3, the torque command output unit 11 outputs the input torque command to the adding unit 13 as it is. The torque command output unit 11 has a speed control unit 111. When controlling the speed of the mechanical device 3, the speed control unit 111 generates a torque command so that the speed of the electric motor (motor) 2 matches the value of the input speed command, and outputs the torque command to the adding unit 13. . The torque command output unit 11 can cope with both the mechanical device 3 that performs the torque control and the mechanical device 3 that performs the speed control.

  The vibration command output unit 12 outputs the vibration command to the adding unit 13 and the resonance point data acquisition unit 30 in order to search the resonance frequency of the mechanical device 3 by changing the frequency of the torque command. The vibration command is a signal in which the frequency is varied within a predetermined range as shown in the vibration command output unit 12 in FIG. The amplitude of the vibration command is set to a range that does not adversely affect the mechanical device 3.

  The adding unit 13 generates a vibration torque command by adding the torque command input from the torque command output unit 11 and the vibration command input from the vibration command output unit 12, and Output to

  The motor control unit 20 includes a torque control unit 21 and a power conversion unit 22, and controls the electric motor 2 based on a vibration torque command input from the vibration torque command generation unit 10.

  The torque control unit 21 generates a voltage command for flowing a current according to the excitation torque command input from the adding unit 13 and outputs the voltage command to the power conversion unit 22.

  The power conversion unit 22 generates a voltage based on the voltage command input from the torque control unit 21, applies the voltage to the electric motor 2, and causes a current to flow through the electric motor 2.

  The electric motor 2 gives a rotational force according to the vibration torque command to a mechanical device 3 connected to the electric motor 2.

  The vibration sensor 31 provided in the mechanical device 3 detects all of the three axes in the vertical direction, the horizontal direction, and the axial direction, or one point where vibration is likely to occur, and detects the vibration generated in the mechanical device 3. , And outputs the detection signal to the frequency analysis unit 40.

  The frequency analysis unit 40 analyzes the frequency of the vibration of the mechanical device 3. Specifically, a frequency conversion process such as FFT (Fast Fourier Transform) is performed on the detection signal input from the vibration sensor 31, and a frequency analysis result is output to the resonance point data acquisition unit 30.

  The resonance point data acquisition unit 30 converts resonance point data indicating the resonance point of the mechanical device 3 from the vibration command input from the vibration command output unit 12 and the frequency analysis result input from the frequency analysis unit 40. decide. For example, a frequency transfer function is obtained from a frequency spectrum of a vibration command input from the vibration command output unit 12 and a frequency spectrum indicating an analysis result by the frequency analysis unit 40, and a Bode diagram of the frequency transfer function is created. I do. The resonance point data acquisition unit 30 acquires, as resonance point data, the frequency and amplitude at which the gain of the frequency transfer function is maximized, obtained from the Bode diagram.

  The abnormality determining unit 50 determines whether there is an abnormality in the mechanical device 3 based on the resonance point data acquired by the resonance point data acquiring unit 30, and when it is determined that the mechanical device 3 has an abnormality, an alarm is issued. Notify the unit 60. For example, in a multi-inertia system, when aging occurs, a resonance point may appear at a frequency different from the conventional frequency. Therefore, the abnormality determination unit 50 compares the resonance point data acquired by the resonance point data acquisition unit 30 with the resonance point data measured in advance when the mechanical device 3 is normal, and a resonance point different from the normal state appears. In this case, it is determined that the mechanical device 3 is abnormal. The abnormality determining unit 50 also determines that the mechanical device 3 has an abnormality even when the difference between the resonance point data acquired by the resonance point data acquiring unit 30 and the resonance point data of the mechanical device 3 in a normal state exceeds the threshold value. It may be determined that there is. In addition, the resonance point data of the mechanical device 3 in the normal state can be measured in advance by controlling the mechanical device 3 in the normal state by the above-described vibration torque command by the mechanical abnormality prediction device 1.

  The alarm unit 60 outputs a warning sound or a warning voice from a speaker, turns on an LED, or generates a warning message on a display when the abnormality determination unit 50 determines that the mechanical device 3 is abnormal. Issue an alarm by any method, such as

  As described above, since the mechanical abnormality prediction device 1 obtains resonance point data of the mechanical device 3 and determines the abnormality, it is possible to predict the abnormality of the mechanical device 3 before the production operation of the mechanical device 3 is performed. . Further, since the input of the torque command output unit 11 can correspond to both the torque command and the speed command, the machine abnormality prediction device 1 can control the mechanical device 3 regardless of whether it controls the torque or the speed. It is possible to predict an abnormality of the device 3. Further, if the output of the vibration command output unit 12 is stopped, the machine abnormality prediction device 1 can be operated as a driver of the electric motor 2, and the mechanical device 3 can be produced and operated by speed control or torque control. .

  Although the above embodiments have been described as representative examples, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, it is possible to combine a plurality of configuration blocks described in the configuration diagram of the embodiment into one, or to divide one configuration block.

REFERENCE SIGNS LIST 1 mechanical abnormality prediction device 2 electric motor 3 mechanical device 10 excitation torque command generation unit 11 torque command output unit 12 excitation command output unit 13 addition unit 20 motor control unit 21 torque control unit 22 power conversion unit 30 resonance point data acquisition unit 31 vibration sensor 40 frequency analysis unit 50 abnormality judgment unit 60 alarm unit 111 speed control unit

Claims (3)

A vibration command generation unit that adds a torque command and a vibration command for vibrating the torque command to generate a vibration torque command;
A motor control unit that controls the motor based on the vibration torque command,
A frequency analysis unit for frequency-analyzing the vibration of the mechanical device connected to the electric motor,
Using the vibration command and the result of the frequency analysis, a resonance point data acquisition unit that acquires resonance point data indicating a resonance point of the mechanical device,
From the resonance point data, an abnormality determining unit that determines whether there is an abnormality in the mechanical device,
A machine abnormality prediction device comprising:   The resonance point data obtaining unit obtains a frequency transfer function from a frequency spectrum of the vibration command and a frequency spectrum indicating a result of the frequency analysis, and obtains the resonance point data based on the frequency transfer function. The machine abnormality prediction device according to claim 1, wherein   The abnormality determining unit compares the resonance point data acquired by the resonance point data acquisition unit with the resonance point data of the mechanical device in a normal state measured in advance to determine whether there is an abnormality in the mechanical device. The machine abnormality prediction device according to claim 1, wherein the determination is performed.

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