WO2023139663A1

WO2023139663A1 - Vibration factor estimating device

Info

Publication number: WO2023139663A1
Application number: PCT/JP2022/001660
Authority: WO
Inventors: 佑貴白川
Original assignee: ファナック株式会社
Priority date: 2022-01-18
Filing date: 2022-01-18
Publication date: 2023-07-27

Abstract

Provided is a vibration factor estimating device that can easily identify a vibration factor. This vibration factor estimating device comprises: a command creating unit that creates a motion command that includes control states of each control axis of an industrial machine; a motor control unit that controls a motor of the industrial machine on the basis of the motion command; a detecting unit that detects, as a detection value of the motor, at least one among the position, the speed, and the acceleration of the motor of the industrial machine; and a vibration factor estimating unit that estimates a vibration factor of the motor on the basis of the motion command and the detection value corresponding to the motion command.

Description

Vibration factor estimation device

The present invention relates to a vibration factor estimation device.

Conventionally, a system for measuring the vibration of the shaft of a machine tool is known (see Patent Document 1, for example). There are various factors in the vibration that occurs in the feed shaft and spindle of industrial machines such as machine tools, and there is a possibility of vibration due to external disturbance in addition to vibration due to resonance and interference of the own shaft, so it may be difficult to identify. In order to improve the machining accuracy, it is necessary to identify the vibration factors of the machine tool, and improve and eliminate the vibration factors.

JP 2020-159752 A

　Vibration factors mainly include (1) resonance and interference of the own axis, (2) vibration of other axes within the same machine tool, vibration of peripheral equipment, disturbances such as noise, and (3) machining load (only during machining). In particular, it may be difficult to separate the vibration factors (1) and (2) under the control of the machine tool. Further, some vibration factors cannot be suppressed by controlling the motor of the machine tool, and it is required to easily identify the vibration factors of industrial machines.

A vibration factor estimating device according to an aspect of the present disclosure includes: a command creation unit that creates an operation command including a control state of each control axis of an industrial machine; a motor control unit that controls a motor of the industrial machine based on the operation command; a detection unit that detects at least one of position, speed, and acceleration of the motor of the industrial machine as a detected value of the motor;

According to the present invention, it is possible to easily identify the vibration factor.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the outline|summary of the vibration factor estimation apparatus which concerns on this embodiment. It is a figure which shows the 1st example of a process of the vibration factor estimation apparatus which concerns on this embodiment. FIG. 4 is a diagram showing the positions of the X-axis, Y-axis, and Z-axis in a normal state; FIG. 4 is a diagram showing the positions of the X-, Y-, and Z-axes when control of the X-axis is disabled; It is a figure which shows the 2nd example of a process of the vibration factor estimation apparatus which concerns on this embodiment. FIG. 4 is a diagram showing the positions of the X-axis, Y-axis, and Z-axis in a normal state; FIG. 4 is a diagram showing the positions of the X-, Y-, and Z-axes when control of the X-axis is disabled; FIG. 4 is a diagram showing the positions of the X-axis, Y-axis, and Z-axis when control of axes other than the X-axis is disabled; It is a figure which shows the example of the 3rd process of the vibration factor estimation apparatus which concerns on this embodiment. FIG. 4 is a diagram showing the positions of the X-axis, Y-axis, and Z-axis in a normal state; FIG. 4 is a diagram showing the positions of the X-, Y-, and Z-axes when control of the X-axis is disabled; FIG. 4 is a diagram showing the positions of the X-axis, Y-axis, and Z-axis when control of axes other than the X-axis is disabled; FIG. 4 is a diagram showing control states of the X-axis, the Y-axis, and the Z-axis; It is a flow chart which shows processing of a vibration factor estimating device concerning this embodiment. It is a flow chart which shows processing of a vibration factor estimating device concerning this embodiment.

An example of an embodiment of the present invention will be described below. FIG. 1 is a diagram showing an overview of a vibration factor estimation device 1 according to this embodiment. The vibration factor estimating device 1 may be, for example, a numerical control device connected to the machine tool 2 as shown in FIG. 1, or may be a computer device connected to the numerical control device.

That is, the vibration factor estimation device 1 includes a processor such as a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores an OS (Operating System) and application programs, a RAM (Random Access Memory) that stores various information, and a hard disk drive or SSD (Solid State Drive) that stores various other information. ) and the like.

The machine tool 2 is a device for machining a workpiece, and is directly or indirectly connected to the vibration factor estimation device 1. The machine tool 2 has a general configuration for machining tools, spindles, feed axes, and the like.

The vibration factor estimation device 1 includes a command generation unit 11, a motor control unit 12, a data storage unit 15, and a vibration factor estimation unit 16. Further, the detection unit 14 may be incorporated in the vibration factor estimation device 1, may be included in the machine tool 2, or may be included in another device. Further, in the present embodiment, the vibration factor estimating device 1 estimates the vibration factor of the servomotor 13, but the vibration factor estimating device 1 can estimate the vibration factor of other industrial machines having servomotors and detection units.

In order to estimate the vibration factor of the machine tool 2, the command creation unit 11 creates an operation command including the control state of each control axis of the machine tool 2 (for example, the main axis, X-axis, Y-axis, Z-axis, etc., which will be described later). In addition, the command creation unit 11 creates an operation command including control enable or control suppression of the servomotor 13 as the control state.

The motor control unit 12 controls the servomotor 13 of the machine tool 2 based on the operation command. Also, the motor control unit 12 detects at least one of position, speed, and acceleration by the detection unit 14 and determines the voltage command value based on the feedback value from the detection unit 14 . The motor control unit 12 controls driving of the motor by applying a voltage modulated by a pulse width modulation (PWM) method.

The servomotor 13 is a motor for driving the main shaft, X-axis, Y-axis, Z-axis, etc. of the machine tool 2 . The amount of rotation, speed, torque, etc. of the servomotor 13 are controlled by the motor control unit 12 . The servomotor 13 includes, for example, a servomotor 13a that drives the X axis, a servomotor 13b that drives the Y axis, a servomotor 13c that drives the Z axis, and a servomotor 13d that drives the main axis.

The detection unit 14 includes an encoder, and detects at least one of the position, speed, and acceleration of the servomotor 13 of the machine tool 2 as a detected value of the servomotor 13 . The detection unit 14 includes, for example, a detection unit 14a that detects the detection value of the servomotor 13a, a detection unit 14b that detects the detection value of the servomotor 13b, a detection unit 14c that detects the detection value of the servomotor 13c, and a detection unit 14d that detects the detection value of the servomotor 13d. Then, the detection unit 14 outputs the detection value to the motor control unit 12 as a feedback value.

The data storage unit 15 stores the operation command created by the command creation unit 11 and the detection value detected by the detection unit 14 in association with each other.

The vibration factor estimator 16 estimates the vibration factor of the servomotor 13 based on the motion command and the detected value corresponding to the motion command.

In addition, the command creation unit 11 adjusts the gain of the servomotor 13, sets the torque command of the servomotor 13 to 0, cuts off the power to the servomotor 13, etc. as a control state, thereby creating an operation command including enabling or inhibiting control of the servomotor 13. Here, the suppression of control of the servomotor 13 includes, for example, not only the case of completely invalidating the gain but also the case of making the gain extremely small.

In addition, the vibration factor estimation unit 16 may compare two or more detection values corresponding to different control states, and estimate whether the vibration factor of the servomotor 13 is an internal factor such as resonance or interference of the shaft driven by a certain servomotor 13 or an external factor such as vibration of the shaft of another servomotor 13, vibration of peripheral equipment, or noise based on the difference between the detected values. Here, in this specification, the internal factor means resonance, interference, or the like that occurs in the own axis (for example, the servomotor 13a) for the axis driven by a certain servomotor 13 (for example, the servomotor 13a). The external factors mean vibrations generated in other servomotors 13 (eg,

servomotors

13b, 13c, .

For example, the vibration factor estimation unit 16 compares two detection values corresponding to different control states. The vibration factor estimator 16 determines that the vibration has been eliminated when the difference obtained by comparing the detected values is equal to or greater than a predetermined threshold value, and when it is determined from the sign of the detected value and the difference that the vibration in the control disabled state is smaller than the vibration in the control enabled state. Thereby, the vibration factor estimator 16 estimates that the vibration factor is an internal factor. In addition, the vibration factor estimating unit 16 determines that the vibration is not eliminated when the difference between the detected values is less than a predetermined threshold value, or when it is determined from the sign of the detected value and the difference that the vibration in the control disabled state is greater than the vibration in the control enabled state. Thereby, the vibration factor estimator 16 estimates that the vibration factor is an external factor.

In addition, the vibration factor estimator 16 may extract at least one feature quantity of the vibration frequency, amplitude, and phase included in the detected value, compare two or more feature quantities corresponding to different control states, and estimate whether the vibration factor of the servo motor 13 is an internal factor or an external factor based on the difference between the feature quantities.

In addition, the vibration factor estimation unit 16 may extract the peak value of the detected value, compare two or more peak values corresponding to different control states, and estimate whether the vibration factor of the servomotor 13 is an internal factor or an external factor based on the difference between the peak values.

Also, when the detection unit 14 detects detection values of a plurality of servo motors 13 (servo motors 13 a, servo motors 13 b, servo motors 13 c, .

FIG. 2 is a diagram showing a first processing example of the vibration factor estimation device 1 according to this embodiment. 3A is a diagram showing the positions of the X-, Y-, and Z-axes in a normal state, and FIG. 3B is a diagram showing the positions of the X-, Y-, and Z-axes when control of the X-axis is disabled.

As shown in FIG. 2, the vibration factor estimation device 1 controls the servomotor 13a that drives the X-axis 17a of the machine tool 2, the servomotor 13b that drives the Y-axis 17b, the servomotor 13c that drives the Z-axis 17c, and the servomotor 13d that drives the main shaft. The detection unit 14a detects the detection value of the servo motor 13a, the detection unit 14b detects the detection value of the servo motor 13b, the detection unit 14c detects the detection value of the servo motor 13c, and the detection unit 14d detects the detection value of the servo motor 13d.

In the processing example shown in FIG. 2, vibration A1 occurs on the X-axis 17a. As shown in FIG. 3A, the positions of the Y-axis 17b and Z-axis 17c fluctuate according to the command, but the position of the X-axis 17a does not follow the command and is unstable. When the vibration factor estimating device 1 disables the control of the X-axis 17a, the position of the X-axis 17a becomes constant and no vibration of the X-axis 17a occurs, as shown in FIG. 3B. Therefore, the vibration factor estimating device 1 estimates that the vibration factor of the X-axis 17a is not an external factor such as other servo motors 13 (servo motor 13b, servo motor 13c, .

FIG. 4 is a diagram showing a second processing example of the vibration factor estimation device 1 according to this embodiment. 5A is a diagram showing the positions of the X, Y, and Z axes during normal operation, FIG. 5B is a diagram showing the positions of the X, Y, and Z axes when control of the X axis is disabled, and FIG. 5C is a diagram illustrating the positions of the X, Y, and Z axes when control of axes other than the X axis is disabled.

In the example of processing shown in FIG. 4, vibration A2 occurs on the X-axis 17a. As shown in FIG. 5A, normally, the positions of the Y-axis 17b and the Z-axis 17c fluctuate according to commands, but the position of the X-axis 17a is unstable. When the vibration factor estimation device 1 disables the control of the X-axis 17a, as shown in FIG. 5B, the positions of the Y-axis 17b and Z-axis 17c fluctuate according to the command, but the position of the X-axis 17a is unstable.

Furthermore, when the vibration factor estimating device 1 disables control of axes other than the X-axis 17a, the positions of the Y-axis 17b and Z-axis 17c are constant, but the position of the X-axis 17a is unstable, as shown in FIG. 5C. Therefore, even if the control of the X-axis 17a is disabled, the X-axis 17a still vibrates, and the difference between the vibration frequency, amplitude and phase included in the detected values is small. Furthermore, control axes other than the X-axis 17a do not affect the vibration. Therefore, the vibration factor estimating device 1 estimates that the vibration factor of the X-axis 17a is an external factor such as other processing machines and peripheral devices other than the other servomotors 13 (

servomotors

13b, 13c, . . . ) of the machine tool 2.

FIG. 6 is a diagram showing a third processing example of the vibration factor estimation device 1 according to this embodiment. 7A is a diagram showing the positions of the X-, Y-, and Z-axes in a normal state, FIG. 7B is a diagram showing the positions of the X-, Y-, and Z-axes when control of the X-axis is disabled, and FIG. 7C is a diagram showing the positions of the X-, Y-, and Z-axes when control of the Y-axis is disabled.

In the processing example shown in FIG. 6, vibration A3 is generated on the Y-axis 17b, and vibration A4 is generated on the X-axis 17a. As shown in FIG. 7A, during normal operation, the position of the Z-axis 17c fluctuates according to the command, but the positions of the X-axis 17a and the Y-axis 17b are unstable.

When the vibration factor estimation device 1 disables the control of the X-axis 17a, as shown in FIG. 7B, the position of the Z-axis 17c fluctuates according to the command, but the positions of the X-axis 17a and Y-axis 17b are unstable. When the vibration factor estimation device 1 disables the control of the Y-axis 17b, as shown in FIG. 7C, the position of the Y-axis 17b becomes constant, and the positions of the X-axis 17a and the Z-axis 17c fluctuate according to commands.

Therefore, even if the control of the X-axis 17a is disabled, the X-axis 17a vibrates, and the difference between the detected values is small. Further, when the control of the Y-axis 17b is invalidated, the Y-axis 17b does not vibrate, the difference is large when the detected values are compared, and furthermore, the X-axis does not vibrate. Therefore, the vibration factor estimation device 1 estimates that the vibration factor of the Y-axis 17b is the Y-axis 17b itself, and the vibration factor of the X-axis 17a is the Y-axis 17b.

FIG. 8 is a diagram showing the control state of the X-axis, Y-axis and Z-axis. 9 and 10 are flowcharts showing the processing of the vibration factor estimation device 1 according to this embodiment. 8 to 10, the vibration factor estimating device 1 estimates X-axis vibration factors in a machine tool 2 having X, Y, and Z axes.

As shown in FIG. 8, control state C1 indicates that control of the X, Y, and Z axes is ON; control state C2 indicates that control of the X axis is OFF and control of the Y and Z axes is ON; control state C3 indicates that control of the X axis is ON and control of the Y and Z axes is OFF; is OFF, control state C5 indicates that control of the X and Y axes is ON and control of the Z axis is OFF, control state C6 indicates that control of the X and Z axes is OFF and control of the Y axis is ON, and control state C7 indicates that control of the X and Y axes is OFF and control of the Z axis is ON.

In step S1 of FIG. 9, the command creation unit 11 creates an operation command including the control states C1 to C5 of the X-, Y-, and Z-axes of the machine tool 2 in order to estimate the X-axis vibration factor.

In step S2, the motor control unit 12 controls the servomotors 13 (for example, the

servomotors

13a, 13b and 13c described above) corresponding to the X, Y and Z axes of the machine tool 2 based on the operation command.

In step S3, the detection unit 14 detects, as detection values of the servomotor 13, a detection value corresponding to the control state C1, a detection value corresponding to the control state C2, and a detection value corresponding to the control state C3. The data storage unit 15 associates and stores the operation commands including the control states C1 to C3 created in step S1 and the detection values detected in step S2.
Specifically, the data storage unit 15 associates and stores an operation command including the control state C1 and a detected value corresponding to the control state C1. Similarly, the data storage unit 15 associates and stores an operation command including the control state C2 and a detected value corresponding to the control state C2, and associates and stores an operation command including the control state C3 and a detected value corresponding to the control state C3.

In step S4, the vibration factor estimator 16 compares the detected value corresponding to the control state C1 and the detected value corresponding to the control state C2.
In step S5, the vibration factor estimator 16 determines whether or not the X-axis vibration has been eliminated in the control state C2. If the X-axis vibration is eliminated (YES), the process proceeds to step S6. On the other hand, if the X-axis vibration is not resolved (NO), the process proceeds to step S7.

In step S6, the vibration factor estimator 16 estimates the X-axis itself as the vibration factor, and terminates the process.

In step S7, the vibration factor estimator 16 estimates that the vibration factor is an external factor, and proceeds to step S8.
In step S8, the vibration factor estimator 16 compares the detected value corresponding to the control state C1 and the detected value corresponding to the control state C3.

In step S9, the vibration factor estimation unit 16 determines whether or not the X-axis vibration has been eliminated. If the X-axis vibration is not resolved (YES), the process proceeds to step S10. On the other hand, if the X-axis vibration has been eliminated (NO), the process proceeds to step S11.

In step S10, the vibration factor estimation unit 16 estimates that the vibration factor is an external factor other than the control axis (other processing machines, peripheral devices, etc.), and terminates the process.

In step S11, the detection unit 14 detects a detection value corresponding to the control state C4 and a detection value corresponding to the control state C5 as the detection values of the servomotor 13. The data storage unit 15 associates and stores the operation commands including the control states C4 and C5 created in step S1 and the detection values detected in step S11.

In step S12, the vibration factor estimator 16 compares the detected value corresponding to the control state C1 and the detected value corresponding to the control state C4.
In step S13, the vibration factor estimator 16 determines whether or not the X-axis vibration has been eliminated in the control state C4. If the X-axis vibration is eliminated (YES), the process proceeds to step S14. On the other hand, if the X-axis vibration is not resolved (NO), the process proceeds to step S15.

In step S14, the vibration factor estimator 16 estimates the Y-axis vibration as the vibration factor, and terminates the process.
In step S15, the vibration factor estimator 16 compares the detected value corresponding to the control state C1 and the detected value corresponding to the control state C5.

In step S16, the vibration factor estimator 16 determines whether or not the X-axis vibration has been eliminated in the control state C4. If the X-axis vibration has been eliminated (YES), the process proceeds to step S17. On the other hand, if the vibration of the X-axis has not been resolved (NO), then the process ends.
In step S17, the vibration factor estimator 16 estimates the Z-axis vibration as the vibration factor, and terminates the process.

In the flowchart described above, the vibration factor estimation device 1 estimates the X-axis vibration factor in the machine tool 2 having the X-, Y-, and Z-axes. However, after estimating the Y-axis vibration as the vibration factor in step S14, the vibration factor estimation device 1 may further estimate the Y-axis vibration factor using the control state C6 in FIG. 8 and the detected value corresponding to the control state C6. Further, after estimating the Z-axis vibration as the vibration factor in step S17, the vibration factor estimation device 1 may estimate the Z-axis vibration factor using the control state C7 and the detected value corresponding to the control state C7.

As described above, according to the present embodiment, the vibration factor estimation device 1 includes the command creation unit 11 that creates an operation command including the control state of each control axis of the machine tool 2; the motor control unit 12 that controls the servo motor 13 of the machine tool 2 based on the operation command; and a vibration factor estimation unit 16 for estimating the vibration factors of No. 3.

As a result, the vibration factor estimating device 1 can extract disturbance components by analyzing the feedback in a state in which the control of the own axis is disconnected, and can easily identify the vibration factor. Therefore, the vibration factor estimation device 1 can reduce man-hours for identifying the vibration factor of the operator. Furthermore, the vibration factor estimating device 1 can improve the machining accuracy of the machine tool 2 by identifying the vibration factor and improving and eliminating the vibration factor.

In addition, the data storage unit 15 stores the operation command created by the command creation unit 11 and the detection value detected by the detection unit 14 in association with each other. Thereby, the vibration factor estimation device 1 can specify the vibration factor using the detected value corresponding to the operation command.

In addition, the command creation unit 11 creates an operation command including control enable or control suppression of the servomotor 13 as the control state. As a result, the vibration factor estimation device 1 can estimate the vibration factor by switching between control enablement and control suppression (including control disablement) of the servomotor 13 .

In addition, the command creation unit 11 adjusts the gain of the servomotor 13, sets the torque command of the servomotor 13 to 0, cuts off the power to the servomotor 13, etc. as a control state, thereby creating an operation command including enabling or inhibiting control of the servomotor 13. Thereby, the vibration factor estimating device 1 can estimate the vibration factor by adjusting the gain of the servomotor 13, adjusting the torque command, or cutting off the power.

In addition, the vibration factor estimation unit 16 may compare two or more detection values corresponding to different control states, and estimate whether the vibration factor of the servomotor 13 is an internal factor or an external factor based on the difference between the detected values.

Further, when the detection unit 14 detects detection values of a plurality of servo motors 13 (servo motor 13 a, servo motor 13 b, servo motor 13 c . . . ), the vibration factor estimation unit 16 may compare two or more detection values corresponding to different control states other than a certain motor, and estimate whether the vibration factor of the servo motor 13 is caused by another servo motor 13 in the same machine tool 2 based on the difference between the detected values. By executing such processing, the vibration factor estimating section 16 can suitably estimate the vibration factor.

Although the embodiment of the present invention has been described above, the vibration factor estimation device 1 can be realized by hardware, software, or a combination thereof. Also, the control method performed by the vibration factor estimation device 1 can be realized by hardware, software, or a combination thereof. Here, "implemented by software" means implemented by a computer reading and executing a program.

Programs can be stored and supplied to computers using various types of non-transitory computer readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROM (Read Only Memory), CD-R, CD-R/W, semiconductor memory (e.g., mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory) y)).

In addition, although each of the above-described embodiments is a preferred embodiment of the present invention, the scope of the present invention is not limited to only the above-described embodiments, and various modifications can be made within the scope of the present invention.

REFERENCE SIGNS LIST 1 vibration factor estimation device 2 machine tool 11 command generation unit 12 motor control unit 13 servo motor 14 detection unit 15 data storage unit 16 vibration factor estimation unit

Claims

a command creation unit that creates an operation command including the control state of each control axis of the industrial machine;
a motor control unit that controls a motor of the industrial machine based on the operation command;
a detection unit that detects at least one of position, speed, and acceleration of a motor of the industrial machine as a detection value of the motor;
a vibration factor estimation unit that estimates a vibration factor of the motor based on the operation command and the detected value corresponding to the operation command;
A vibration factor estimation device comprising:
The vibration factor estimation device according to claim 1, further comprising a data storage unit that associates and stores the operation command created by the command creation unit and the detection value detected by the detection unit.
3. The vibration factor estimation device according to claim 1 or 2, wherein the command creation unit creates the operation command including control enable or control suppression of the motor as the control state.
　The vibration factor estimating device according to claim 3, wherein the command creation unit creates the operation command including control enable or control suppression of the motor by adjusting the gain of the motor, setting the torque command of the motor to 0, or cutting off the power to the motor as the control state.
The vibration factor estimating device according to any one of claims 1 to 4, wherein the vibration factor estimation unit compares two or more of the detected values corresponding to the different control states, and estimates whether the vibration factor of the motor is an internal factor or an external factor based on the difference between the detected values.
The vibration factor estimating device according to any one of claims 1 to 4, wherein the vibration factor estimating unit extracts at least one feature quantity of vibration frequency, amplitude, and phase included in the detected value, compares two or more of the feature quantities corresponding to the different control states, and estimates whether the vibration factor of the motor is an internal factor or an external factor based on the difference between the feature quantities.
The vibration factor estimating device according to any one of claims 1 to 4, wherein the vibration factor estimation unit extracts the peak value of the detected value, compares two or more of the peak values corresponding to the different control states, and estimates whether the vibration factor of the motor is an internal factor or an external factor based on the difference between the peak values.
The detection unit detects detection values of the plurality of motors,
The vibration factor estimation device according to any one of claims 1 to 4, wherein the vibration factor estimating unit compares two or more of the detected values corresponding to the different control states of a motor other than a certain motor, and estimates whether the vibration factor of the motor is the factor of another motor in the industrial machine based on a difference between the detected values.