WO2020050236A1

WO2020050236A1 - Information processing device and information processing method

Info

Publication number: WO2020050236A1
Application number: PCT/JP2019/034518
Authority: WO
Inventors: 仁友定; 克行木村
Original assignee: オムロン株式会社
Priority date: 2018-09-07
Filing date: 2019-09-03
Publication date: 2020-03-12
Also published as: JP7110845B2; JP2020043650A

Abstract

The present invention accurately detects abnormalities at a moving device. According to the present invention, a difference computation part (55) of a PLC (50) computes the difference between a prediction value for a command value and an indicator that is associated with the rotation of a motor (30), and an abnormality detection part (57) determines that there is an abnormality when a feature quantity for the difference is at or above a threshold value.

Description

Information processing apparatus and information processing method

The present invention relates to an information processing device and an information processing method.

装置 A device that monitors the operation of a movable device that performs a predetermined operation to detect the presence or absence of an abnormality in the movable device is used. In the drawing device of Patent Document 1, the presence or absence of an abnormality in the drawing device is determined by obtaining an average value and a standard deviation of a difference between a set stroke and a detection stroke of a slab for a plurality of cycles.

Japanese Unexamined Patent Publication "JP-A-6-226405"

ずれ There is a gap between the speed instruction value (target value) input to the movable device when operating under speed control and the speed when the movable part of the movable device actually moves. In particular, immediately after the start of the operation of the movable part and immediately before the end of the operation, the deviation becomes large.

Therefore, if the presence or absence of an abnormality in the movable device is detected based on a comparison between an instruction value input to the movable device and an output value when the movable device actually operates, a slight change due to the abnormality in the movable device may be noticed. May not be. An object of one embodiment of the present invention is to accurately detect an abnormality of a movable device.

The present invention employs the following configuration in order to solve the above-described problems.

That is, the information processing apparatus according to one aspect of the present invention provides an index associated with the rotation of a motor that causes a movable device to perform a predetermined operation when the driver rotates the motor based on an input instruction value over time. An acquiring unit for acquiring, the index acquired by the acquiring unit, and a difference computing unit that computes, over time, a difference between the index and an expected value of the index associated with the rotation of the motor based on the indicated value; and a predetermined period of the difference. And a failure detection unit that detects a failure of the movable device by comparing the feature value with a threshold value.

An information processing method according to one aspect of the present invention is an acquisition step of sequentially acquiring an index associated with rotation of a motor that causes a movable device to perform a predetermined operation when the driver rotates the motor based on an instruction value, A difference calculating step of calculating, over time, a difference between the index acquired in the acquiring step and an expected value of the index associated with rotation of the motor based on the instruction value; A feature value calculating step of calculating; and an abnormality detecting step of detecting an abnormality of the movable device by comparing the feature value with a threshold.

According to one embodiment of the present invention, it is possible to accurately detect an abnormality in a movable device.

FIG. 2 is a diagram illustrating an example of a functional block of the PLC according to the first embodiment. FIG. 3 is a diagram schematically illustrating an example of an application scene of the PLC according to the first embodiment. FIG. 3 is a diagram illustrating respective waveforms of an instruction value, an ideal waveform, and a measurement value according to the first embodiment. 5 is a waveform showing a difference between an output value associated with rotation of a motor and an expected value, calculated by a difference calculation unit according to the first embodiment. FIG. 3 is a diagram illustrating a flow of processing of the PLC according to the first embodiment.

Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings.

§1 Application Example An example of a scene to which the present invention is applied will be described with reference to FIG. FIG. 2 is a diagram schematically illustrating an example of an application scene of a PLC (programmable logic controller) 50 according to the first embodiment. The PLC 50 according to the present embodiment is an example of the information processing apparatus of the present invention that detects an abnormality of the movable device 10 including the movable mechanism (the movable portion 13 and the ball screw 12) that performs a predetermined operation by the rotation of the motor 30 in real time. .

The movable system 1 includes the movable device 10, the motor 30, a driver 40 that controls the driving of the motor 30, and a PLC 50. The movable system 1 is, for example, a production facility used in a product manufacturing factory. The movable device 10 is a device that performs a predetermined operation, for example, by transmitting rotation of a motor 30 connected via the coupling 20. The movable device 10 may be any device that performs a predetermined operation when the rotation of the motor 30 is transmitted, and may be, for example, various devices such as a transport device used in a manufacturing plant, or used in a device other than the manufacturing plant. Devices such as various types of robots.

The PLC 50 acquires an index associated with the rotation of the motor 30 over time, and detects an abnormality of the movable device 10 based on a difference between an expected value of the index and the acquired index. The predicted value is predicted based on the indicated value (control target value) and is different from the indicated value (control target value). The predicted value represents a measured value of the index in the normal movable device 10 (for example, an average value). Note that the PLC 50 may be any information processing device that detects an abnormality of the movable device 10 based on a difference between the expected value of the index and the index, and the information processing device may be, for example, a server. . Specific examples of the index will be described later.

§2 Configuration Example A configuration example of the movable system 1 according to the first embodiment will be described with reference to FIG. The movable device 10 includes, for example, a base 11 having a linear guide, a ball screw 12, and a movable portion 13. The ball screw 12 is mounted on the base 11 so as to be parallel to the long axis direction of the base 11. The movable section 13 is mounted on the ball screw 12. One end of the ball screw 12 is connected to an output shaft of a motor 30 via a coupling 20.

(4) The rotation of the output shaft of the motor 30 (simply called the rotation of the motor 30) causes the ball screw 12 to rotate. Then, as the ball screw 12 rotates, the movable portion 13 moves (ie, moves) on the ball screw 12 and along the ball screw 12 as indicated by an arrow A1.

In the movable device 10, for example, the movable portion 13 moves from the vicinity of one end (the end closer to the motor 30) of the ball screw 12 to the vicinity of the other end (the end farther from the motor 30) (outbound path). The movable portion 13 moves from the vicinity of the other end of the ball screw 12 to the vicinity of one end (return direction) of the ball screw 12 as a one-cycle operation. . The predetermined operation in the movable device 10 may be the one-cycle operation or a plurality of cycles including the one-cycle operation a plurality of times.

実施 In the present embodiment, description will be made assuming that the motor 30 includes the encoder 35. The encoder 35 outputs information indicating the rotation direction and the rotation angle of the motor 30 to the driver 40 over time as a pulse signal.

The encoder 35 may be externally provided separately from the motor 30. When the encoder 35 is provided separately from the motor 30, for example, the encoder 35 is attached to the other end of the ball screw 12 (the end farther from the motor 30) via a coupling. Then, the encoder 35 outputs information indicating the rotation direction and the rotation angle of the ball screw 12 to the PLC 50 with time as a pulse signal.

Note that the encoder 35 built in the motor 30 or an external encoder 35 provided separately from the motor 30 makes contact between the rotating part and a sensing part that senses the rotation direction and the rotation angle of the rotating part. Contact type encoder, or a non-contact type encoder in which the rotating part and the sensing part are in non-contact.

For example, the driver 40 sets an appropriate value of current and voltage based on an instruction value (control target value) from the PLC 50 so that the number of revolutions of the motor 30 per unit time becomes the instruction value (control target value). And outputs the generated current and voltage to the motor 30. Thus, the driver 40 controls the rotation of the motor 30. For example, the driver 40 calculates a torque value, which is an output value associated with the rotation of the motor 30, with time based on the current value and the voltage value of the current and the voltage output to the motor 30, and sequentially outputs the torque value to the PLC 50. .

An instruction value (control target value) from the PLC 50 input to the driver 40, a current value and a voltage value output from the driver 40 to the motor 30, and a torque value calculated from the current value and the voltage value are determined by the rotation of the motor 30. 7 is an example of a control value for controlling the motor 30 among the indices associated with.

Further, the driver 40 changes the angular velocity value (in other words, the rotation speed of the motor 30) which is the output value (measured value) accompanying the rotation of the motor 30 with time based on the pulse signal acquired from the encoder 35 provided in the motor 30. And sequentially output to the PLC 50.

In addition, for example, an acceleration sensor is attached to the movable unit 13, the acceleration sensor acquires the acceleration data of the movable unit 13 that moves with the rotation of the motor 30 over time, and the acceleration sensor determines the acceleration value indicating the acceleration value. The data may be sequentially output to the PLC 50 as an output value accompanying the rotation of the motor 30.

In addition, for example, an acceleration sensor is attached to the movable unit 13, the acceleration sensor acquires the acceleration data of the movable unit 13 that moves with the rotation of the motor 30 over time, and the acceleration sensor determines the acceleration value indicating the acceleration value. The data may be sequentially output to the PLC 50 as an output value accompanying the rotation of the motor 30. Further, for example, a position sensor is attached to the movable unit 13, and the position sensor acquires the position data of the movable unit 13 that moves with the rotation of the motor 30 over time, and the position sensor acquires the position data of the movable unit 13. May be sequentially output to the PLC 50 as an output value associated with the rotation of the motor 30.

As described above, the rotation speed of the motor 30 calculated from the pulse signal output from the motor 30 to the driver 40, or the acceleration value and the position obtained from a separately provided sensor are determined by the rotation of the motor 30. It is an example of an output value (measured value) accompanying rotation of the motor 30 among the accompanying indexes. Note that the output value (measured value) associated with the rotation of the motor 30 may be a value obtained by measuring with the rotation of the motor 30.

FIG. 1 is a diagram illustrating an example of functional blocks of the PLC 50 according to the first embodiment. The PLC 50 includes an instruction unit 51, a predicted value calculation unit 52, a storage unit 53, an acquisition unit 54, a difference calculation unit 55, a feature value calculation unit 56, and an abnormality detection unit 57. Hereinafter, each unit included in the PLC 50 will be described.

FIG. 3 is a diagram showing the waveforms of the indicated value, the ideal waveform, and the measured values 1 and 2 according to the first embodiment.

The instruction unit 51 outputs the instruction values shown in FIG. The instruction value output from the instruction unit 51 to the driver 40 is a target value of an index associated with the rotation of the motor 30.

The index associated with the rotation of the motor 30 includes a current value and a voltage value (control value) generated by the driver 40 based on the instruction value, a torque value (control value) calculated from the current value and the voltage value, and a rotation of the motor 30. Output value (measurement value) associated with the above. The output value (measured value) accompanying the rotation of the motor 30 is, for example, the rotation speed of the motor 30 at which a pulse signal output from the encoder 35 is calculated, or an acceleration value, a position, or the like obtained from a separately provided sensor. Can be mentioned. In particular, since the torque and the speed are indexes when the movable device 10 is moving, the abnormality of the movable device 10 is likely to be reflected in the values. Therefore, the presence or absence of an abnormality in the movable device 10 can be detected at an early stage.

When the instruction value is the control target value of the torque, when the driver 40 obtains the instruction value from the instruction unit 51, the driver 40 generates a current and a voltage having such a value that the torque of the motor 30 becomes the instruction value, and generates the current. The motor 30 is rotated by the current and the voltage. Thereby, the motor 30 rotates so that the torque becomes the indicated value. When the instruction value is the target value of the rotating speed of the motor 30, the driver 40 obtains the instruction value from the instruction unit 51, and sets the current and the value of the value such that the rotating speed of the motor 30 becomes the instruction value. A voltage is generated, and the motor 30 is rotated by the generated current and voltage. Thereby, the motor 30 rotates so that the speed becomes the indicated value. When the instruction value is the target value of the speed of the movable unit 13, the driver 40 obtains the instruction value from the instruction unit 51, and outputs a current and a voltage of such values that the speed of the movable unit 13 becomes the instruction value. Then, the motor 30 is rotated by the generated current and voltage. As a result, the motor 30 rotates so that the speed of the movable unit 13 becomes the specified value.

In the example shown in FIG. 3, the waveform of the instruction value output from the instruction unit 51 to the driver 40 represents an example in which the target value of the rotation speed of the motor 30 is used. Further, in the example shown in FIG. 3, the waveform of the instruction value is not a waveform that switches smoothly during acceleration, constant speed, and deceleration, but is a rectangular shape. In addition, the example shown in FIG. 3 shows a waveform of an instruction value when the movable unit 13 operates in one cycle.

In the case where the information processing apparatus according to the present invention is not a PLC but a server, the instruction unit 51 may be omitted, and the instruction value may be obtained from a separately provided PLC.

The predicted value calculation unit 52 generates a predicted value of an index associated with the rotation of the motor 30 based on the command value output from the command unit 51 to the driver 40, and stores the predicted value in the storage unit 53 in advance. The predicted value calculation unit 52 creates in advance a database representing the correspondence between the indicated value output by the indicating unit 51 and an index associated with the rotation of the motor 30 with respect to the indicated value, and stores the database in the storage unit 53. You should keep it. In addition, the expected value calculation unit 52 previously creates a transfer function indicating the correspondence between the indicated value output by the indicating unit 51 and an index associated with the rotation of the motor 30 with respect to the indicated value, and stores the transfer function. The information may be stored in the unit 53.

(3) The example shown in FIG. 3 represents an ideal waveform which is a waveform of an expected value corresponding to the waveform of the indicated value output from the indicating unit 51.

As shown in FIG. 3, the index associated with the rotation of the motor 30 has a waveform that follows the waveform of the indicated value output by the indicating unit 51, but is exactly the same as the waveform of the indicated value output by the indicating unit 51. And some deviation occurs. In particular, the ideal waveform is obtained immediately after the rising of the waveform of the indicated value output from the indicating unit 51 (that is, immediately after the rotation of the motor 30 is started from a stopped state) and from the falling of the waveform of the indicated value output by the indicating unit 51. Until the motor 30 stops (ie, from the deceleration state of the motor 30 to the stop of the rotation), the deviation from the waveform of the indicated value increases.

As described above, the storage unit 53 stores a database or a transfer function for obtaining an expected value of an index associated with the rotation of the motor 30 with respect to the indicated value. The expected value of the output value accompanying the rotation of the motor 30 with respect to the waveform of the indicated value may be stored in the storage unit 53 as a waveform. The storage unit 53 may be provided outside the PLC 50 or may be externally connected to the PLC 50.

The acquisition unit 54 acquires an index associated with the rotation of the motor 30 when the driver 40 rotates based on the instruction value from the driver 40 over time. In the example illustrated in FIG. 3, an example in which the measured value of the rotating speed of the motor 30 is acquired twice from the driver 40 as an index associated with the rotation of the motor 30 as indicated by the measured value 1 and the measured value 2 Represents. The measured value of the rotation speed of the motor 30 is, for example, the rotation speed of the motor 30 obtained by the driver 40 from the encoder 35. As shown by the measured value 1 and the measured value 2 in FIG. 3, the waveform of the measured value of the rotating speed of the motor 30 has a large difference from the waveform of the indicated value, but the difference from the ideal waveform is small. The shape is along.

Based on the instruction value acquired from the instruction unit 51, the difference calculation unit 55 acquires, from the storage unit 53, the predicted value of the output value accompanying the rotation of the motor 30 based on the instruction value over time. Then, the difference calculation unit 55 calculates the difference between the index acquired by the acquisition unit 54 associated with the rotation of the motor 30 and the predicted value acquired from the storage unit 53 over time.

FIG. 4 is a waveform showing a difference between an index associated with the rotation of the motor 30 and an expected value, calculated by the difference calculation unit 55 according to the first embodiment. In FIG. 4, the difference between the ideal waveform shown in FIG. 3 and the measured value 1 is represented by a difference 1, and the difference between the ideal waveform and the measured value 2 is represented by a difference 2 as a waveform. That is, the difference 1 represents a deviation of the measured value 1 from the ideal waveform shown in FIG. 3, and the difference 2 represents a deviation of the measured value 2 from the ideal waveform shown in FIG. In other words, the difference 1 and the difference 2 indicate a difference between an expected output value associated with the rotation of the motor 30 and an actual output value associated with the rotation of the motor 30. Note that the difference between the measured value and the expected value, such as the difference 1 and the difference 2, may be referred to as a disturbance component.

The feature value calculation unit 56 calculates a feature value of a difference (turbulence component) between a predicted value of an output value accompanying rotation of the motor 30 and an index associated with actual rotation of the motor 30 in a predetermined period. For example, the feature value calculation unit 56 calculates the feature value of the difference 1 in one cycle shown in FIG. 4 and / or the feature value of the difference 2 in one cycle shown in FIG. The feature value calculated by the feature value calculation unit 56 includes an average value of absolute values of differences in a predetermined period, a difference between a maximum value and a minimum value of the difference in a predetermined period, or a variance of the difference in a predetermined period. This is a variation amount of the index in a predetermined period.

Particularly, by calculating the average value of the absolute values of the differences 1 and 2 in the predetermined period as the feature amount, the difference is accumulated over the predetermined period, so that a small deviation from the predicted value can be detected. Therefore, the abnormality of the movable device 10 can be accurately and early detected.

The predetermined period may be a period of an integral multiple cycle (one or more cycles) of the movable device 10.

The abnormality detection unit 57 compares the feature amount calculated by the feature amount calculation unit 56 with a threshold. Then, when the feature amount becomes equal to or larger than the threshold value, the abnormality detection unit 57 detects that an abnormality has occurred in the movable device 10. Then, when detecting that an abnormality has occurred in the movable device 10, the abnormality detection unit 57 performs a process of notifying the user.

According to the PLC 50, the difference calculation unit 55 calculates the difference between the index acquired by the acquisition unit 54 and the predicted value based on the instruction value stored in the storage unit 53 over time. Then, the feature value calculation unit 56 calculates the feature value of the difference in a predetermined period. Then, the abnormality detection unit 57 detects an abnormality of the movable device 10 by comparing the feature amount with the threshold. For this reason, a smaller change in the index can be detected as compared with the case where the abnormality of the movable device 10 is detected based on the difference between the indicated value and the index. As a result, the abnormality of the movable device 10 can be accurately detected.

処理 Note that the process of notifying the user includes various methods for notifying the user. Examples of the process of notifying the user include displaying a screen for notifying the user on the display when the movable system 1 includes a display, and outputting a sound for notifying the user when the movable system 1 includes a speaker. For example, to output the data to Alternatively, as a process of notifying the user, for example, a process of notifying the user by sending an e-mail to an address designated by the user, or a process of turning on or blinking the lamp when the movable system 1 includes a lamp And the like.

FIG. 5 is a diagram illustrating a processing flow of the PLC 50 according to the first embodiment. First, the expected value calculation unit 52 calculates an expected value of an index associated with the rotation of the motor 30 based on the instruction value output from the instruction unit 51 to the driver 40, and stores a waveform (ideal waveform) of the expected value in the storage unit 53. (Step S11). Next, the instruction unit 51 calculates an instruction value at which the rotation speed of the motor 30 is targeted, and outputs the instruction value to the driver 40 (step S12). Then, the driver 40 sets the voltage and the current (that is, sets the torque) so that the indicated value obtained by the indicating unit 51 is obtained, and rotates the motor 30. Then, the acquisition unit 54 acquires the rotation speed (index) of the motor 30 from the driver 40 with time (step S13). Next, the difference calculation unit 55 refers to the storage unit 53, acquires an expected value based on the instruction value obtained from the instruction unit 51 (that is, acquires an ideal waveform, and acquires the rotation speed (index) of the motor 30 acquired by the acquisition unit 54). (Step S14) Then, the feature value calculation unit 56 calculates the feature value of the difference calculated by the difference calculation unit 55 for each predetermined time (Step S15). The unit 57 compares the feature value calculated by the feature value calculation unit 56 with a threshold value (step S16), and when the feature value is equal to or larger than the threshold value (YES in step S16), performs notification processing to the user (step S17). .

[Example of software implementation]
The control blocks of the PLC 50 (in particular, the instruction unit 51, the expected value calculation unit 52, the acquisition unit 54, the difference calculation unit 55, the feature value calculation unit 56, and the abnormality detection unit 57) are logic circuits formed on an integrated circuit (IC chip) or the like. It may be realized by a circuit (hardware) or by software.

In the latter case, the PLC 50 includes a computer that executes instructions of a program that is software for realizing each function. The computer includes, for example, one or more processors and a computer-readable recording medium storing the program. Then, in the computer, the object of the present invention is achieved when the processor reads the program from the recording medium and executes the program. As the processor, for example, a CPU (Central Processing Unit) can be used. Examples of the recording medium include "temporary tangible media" such as ROM (Read Only Memory), tapes, disks, cards, semiconductor memories, and programmable logic circuits. Further, a RAM (Random Access Memory) for expanding the above program may be further provided. Further, the program may be supplied to the computer via an arbitrary transmission medium (a communication network, a broadcast wave, or the like) capable of transmitting the program. Note that one embodiment of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

(Appendix)
An information processing device according to one aspect of the present invention acquires an index associated with rotation of a motor that causes a movable device to perform a predetermined operation when the driver rotates the motor based on an input instruction value over time. An acquisition unit, a difference calculation unit that calculates a difference between the index acquired by the acquisition unit and an expected value of an index associated with rotation of the motor based on the indicated value over time, and a feature of the difference in a predetermined period. The mobile device includes a feature value calculation unit that calculates an amount, and an abnormality detection unit that detects an abnormality of the movable device by comparing the feature value with a threshold. For this reason, a smaller change in the index can be detected as compared with the case where the abnormality of the movable device is detected based on the difference between the instruction value and the index. As a result, it is possible to accurately detect the abnormality of the movable device.

記憶 A storage unit may be provided that stores in advance an expected value corresponding to an index associated with the rotation of the motor based on the instruction value.

The feature value may be an average value of absolute values of the difference during the predetermined period. According to this, the difference is accumulated over a predetermined period, so that a small deviation from the expected value can be detected. Therefore, the abnormality of the movable device can be accurately and early detected.

The feature value may be a difference between a maximum value and a minimum value of the difference during the predetermined period, or a variance of the difference during the predetermined period.

The index associated with the rotation of the motor may be the torque of the motor.

The index associated with the rotation of the motor may be a speed at which the motor rotates. Since the torque and the speed are indexes when the movable device is moving, the abnormality of the movable device is likely to be reflected in the values. Therefore, the presence or absence of an abnormality in the movable device can be detected at an early stage.

The present invention is not limited to the embodiments described above, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Movable system 10 Movable device 11 Base 12 Ball screw 13 Movable part 20 Coupling 30 Motor 35 Encoder 40 Driver 50 PLC
51 instruction unit 52 predicted value calculation unit 53 storage unit 54 acquisition unit 55 difference calculation unit 56 feature calculation unit 57 abnormality detection unit

Claims

An acquisition unit that acquires, with time, an index associated with the rotation of the motor when the driver rotates the motor that causes the movable device to perform the predetermined operation based on the input instruction value;
A difference calculating unit that calculates a difference between the index obtained by the obtaining unit and an expected value of the index associated with the rotation of the motor based on the indicated value over time,
A feature value calculation unit that calculates a feature value of the difference in a predetermined period;
An information processing apparatus comprising: an abnormality detection unit that detects an abnormality of the movable device by comparing the feature amount with a threshold.
The information processing apparatus according to claim 1, further comprising: a storage unit that stores an expected value corresponding to an index associated with rotation of the motor based on the instruction value in advance.
The information processing apparatus according to claim 1 or 2, wherein the feature amount is an average value of absolute values of the difference during the predetermined period.
The information processing apparatus according to claim 1 or 2, wherein the feature amount is a difference between a maximum value and a minimum value of the difference during the predetermined period, or a variance of the difference during the predetermined period.
The information processing apparatus according to any one of claims 1 to 4, wherein the index associated with the rotation of the motor is a torque of the motor.
The information processing apparatus according to any one of claims 1 to 4, wherein the index associated with the rotation of the motor is a speed at which the motor rotates.
An acquisition step of acquiring an index associated with the rotation of the motor when the driver rotates the motor for performing the predetermined operation based on the instruction value with time,
A difference calculation step of calculating, over time, a difference between the index acquired in the acquisition step and an expected value of an index associated with rotation of the motor based on the indicated value,
A feature value calculating step of calculating a feature value in a predetermined period of the difference;
An abnormality detection step of detecting an abnormality of the movable device by comparing the feature amount with a threshold value.