CN115706551A - Motor control device and motor control method - Google Patents
Motor control device and motor control method Download PDFInfo
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- CN115706551A CN115706551A CN202210850484.3A CN202210850484A CN115706551A CN 115706551 A CN115706551 A CN 115706551A CN 202210850484 A CN202210850484 A CN 202210850484A CN 115706551 A CN115706551 A CN 115706551A
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- 230000010355 oscillation Effects 0.000 claims description 68
- 230000002238 attenuated effect Effects 0.000 description 16
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- 230000003044 adaptive effect Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
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- 238000005457 optimization Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
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Abstract
The motor control device of the invention restrains unstable control. A servo amplifier (100) for adjusting the gain of a motor (300) analyzes a feedback signal, and when it is determined that there is a vibration of a predetermined reference level or higher, a torque adjustment unit (140) makes the intensity of a notch filter (141) stronger than the initial setting when the peak frequencies of adjacent vibrations determined by the servo amplifier (100) are within a predetermined range, thereby overlapping and attenuating the peak frequencies of vibrations within the predetermined range.
Description
Technical Field
The present invention relates to a motor control device and a motor control method having an auto-tuning function.
Background
When a motor of a servo system is mounted on a target device such as a robot or a machine tool, it is necessary to adjust the gain of a servo amplifier in accordance with the load inertia. The gain adjustment of such a servo amplifier is often performed by a motor control device having an auto-tuning function.
In the auto-tuning, a plurality of test operations are performed while changing tuning parameters, and parameters to be set next are determined based on results of the various test operations. In particular, in order to suppress oscillation on the motor side at a resonance point existing in the target apparatus, it is necessary to set a notch filter capable of suppressing a resonance peak, for example.
As a technique related to such auto-tuning, patent document 1 proposes an auto-adjustment method of a motor control device, the method including: the controller adaptively adjusts the controller using the estimate value by using the estimate value, and by using the adaptive updating unit, the estimate value is adopted as a notch frequency by the notch filter unit, and the unit of the estimate value is converted to Hertz by the unit conversion unit and output as the estimate value.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2021-087276
Disclosure of Invention
In the automatic adjustment method of the motor control device of patent document 1, since the notch frequency of the notch filter is set in the vicinity of the frequency of the resonance point of the resonance frequency of the target device, it is considered that the frequency level of the resonance point can be attenuated.
However, when there are a plurality of resonance points of the resonance frequency of the target device within a certain range, even if the notch frequency of the notch filter is set in the vicinity of the frequency of the resonance point, the frequency level of the resonance point within the certain range cannot be attenuated, and there is a possibility that the control becomes unstable.
The present invention has been made in view of such circumstances, and an object thereof is to provide a motor control device and a motor control method that can solve the above-described problems.
The motor control device of the present invention is characterized by comprising: a servo amplifier that adjusts a gain of the motor; and a torque adjustment unit having a notch filter, wherein the servo amplifier analyzes the feedback signal and determines whether or not there is a vibration of a predetermined reference level or more, and the torque adjustment unit increases the intensity of the notch filter more than the initial setting when the peak frequency of the adjacent vibrations determined by the servo amplifier is within a predetermined range.
The motor control method of the present invention is characterized in that the presence or absence of vibration above a predetermined reference level is determined by analyzing a feedback signal by a servo amplifier that adjusts the gain of the motor, and the intensity of a notch filter is made stronger than the initial setting by a torque adjusting unit having the notch filter when the peak frequency of adjacent vibration determined by the servo amplifier is within a predetermined range.
In the motor control device and the motor control method according to the present invention, the servo amplifier that adjusts the gain of the motor analyzes the feedback signal to determine whether or not there is vibration of a predetermined reference level or more, and the torque adjusting unit having the notch filter makes the intensity of the notch filter stronger than the initial setting when the peak frequency of adjacent vibration determined by the servo amplifier is within a predetermined range.
According to the motor control device and the motor control method of the present invention, since the peak frequency of the vibration within a certain range is attenuated while being covered, it is possible to suppress the control from becoming unstable.
Drawings
Fig. 1 is a diagram for explaining an embodiment of a motor control device according to the present invention.
Fig. 2A is a diagram for explaining torque adjustment performed by the servo amplifier of fig. 1 for an oscillation frequency exceeding a certain reference level, and is a diagram showing a case where a notch filter is set for one oscillation.
Fig. 2B is a diagram for explaining torque adjustment of the servo amplifier in fig. 1 for an oscillation frequency exceeding a certain reference level, and shows a case where the second oscillation exists at a position separated from the first oscillation by a certain range or more.
Fig. 2C is a diagram for explaining torque adjustment performed by the servo amplifier of fig. 1 for an oscillation frequency exceeding a certain reference level, and is a diagram showing a case where a notch filter is set for the second oscillation.
Fig. 3A is a diagram for explaining torque adjustment of the oscillation frequency exceeding a certain reference level by the servo amplifier of fig. 1, and is a diagram showing a notch filter in a case where the peak frequency of adjacent oscillations is set within a certain range.
Fig. 3B is a diagram for explaining torque adjustment of the oscillation frequency exceeding a certain reference level by the servo amplifier of fig. 1, and is a diagram showing a notch filter in a case where the peak frequency of adjacent oscillations is set within a certain range.
Fig. 3C is a diagram for explaining torque adjustment of the oscillation frequency exceeding a certain reference level by the servo amplifier of fig. 1, and is a diagram showing a notch filter when the peak frequency of adjacent oscillations is set within a certain range.
Fig. 4 is a flowchart for explaining automatic tuning by the servo amplifier of fig. 1.
Detailed Description
An embodiment of a motor control device according to the present invention will be described below with reference to fig. 1 to 4. Note that, in the motor control device M described below, it is necessary to adjust the gain of the servo amplifier 100 in accordance with the load inertia when performing auto-tuning, but for convenience of description, illustration and description of the load inertia are omitted. The frequency values described below are values that are easy to describe for convenience of description.
The motor control device M includes a servo amplifier 100 having an auto-tuning function. The servo amplifier 100 performs processing of performing FFT (Fast Fourier Transform) analysis on the encoder pulse as a feedback signal and extracting the vibration frequency. When the peak value of the extracted oscillation frequency exceeds a predetermined reference level, the servo amplifier 100 determines that the oscillation is caused. Reference numeral 300 denotes a motor, reference numeral 150 denotes a subtractor, and reference numeral 160 denotes an adder-subtractor.
The servo amplifier 100 includes a position adjusting unit 110, a feedforward control unit 120, a feedback control unit 130, a torque adjusting unit 140, and a current control unit 170.
The position adjusting unit 110 outputs a position command corresponding to the gain setting to the feedforward control unit 120 and the subtractor 150 based on a command indicating target values of command values including a position, a speed, and a torque from a controller, not shown.
The feedforward control unit 120 outputs a feedforward command (FF command) including a speed command and a torque command for controlling speed and torque to the adder-subtractor 160 based on the position command from the position adjustment unit 110.
The feedback control unit 130 outputs a feedback command (FB command) to the adder-subtractor 160 so that the deviation from the subtractor 150 becomes 0, based on the feedback signal.
The first and second notch filters 141 and 142 are not limited to the two shown, and three or more notch filters may be provided. Further, as the first notch filter 141 and the second notch filter 142, adaptive filters capable of adapting a transfer function according to an optimization algorithm may be used. The detailed settings of the first notch filter 141 and the second notch filter 142 will be described later.
The subtractor 150 subtracts the position command corresponding to the gain setting from the position adjustment unit 110 and the position and velocity signal of the feedback signal, and outputs a deviation. The adder-subtractor 160 subtracts the feedforward command and the feedback command, and outputs a control command for setting the deviation from the subtractor 150 to 0.
The current control section 170 controls the drive current of the motor 300 to generate the torque indicated by the adjustment command from the torque adjustment section 140.
When a command is output from a controller (not shown), the motor control device having such a configuration starts driving the motor 300 based on a feed-forward command (FF command) from the feed-forward control unit 120.
When a feedback signal detected by an encoder (not shown) is output as the motor 300 is driven, a control command for setting the deviation from the subtractor 150 to 0 is output from the adder-subtractor 160 in accordance with a feedback command (FB command) from the feedback control unit 130. Then, the current control section 170 controls the driving current of the motor 300 to generate the torque indicated by the adjustment command after damping the vibration from the torque adjustment section 140.
Next, the setting of the torque adjustment unit 140 will be described with reference to fig. 2A to 3C. For convenience of explanation, fig. 2A to 3C only show vibrations exceeding a certain reference level. The vertical axis shows the level of oscillation and the depths of first notch filter 141 and second notch filter 142, and the horizontal axis shows the frequency.
As shown in fig. 2A, the frequency of 9 is, for example, set to 360Hz when the peak frequency of the oscillation is 400 Hz. Thus, after first notch filter 141 and second notch filter 142 are set, the phase of the notch frequency can be made to coincide with the peak frequency of oscillation.
Fig. 2A shows a case where there is one vibration due to oscillation of the servo amplifier 100. In this case, the torque adjustment unit 140 sets the notch frequency of the first notch filter 141 to a frequency (360 Hz) of 9 of the peak frequency (400 Hz) of the oscillation. Thus, after the first notch filter 141 is set, the phase of the notch frequency can be made to coincide with the peak frequency of the oscillation, and the peak frequency of the oscillation (400 Hz) can be attenuated as shown by the broken line in fig. 2B.
Fig. 2B shows a case where there are two vibrations due to oscillation of the servo amplifier 100. In this case, as shown in fig. 2C, when the peak frequency (800 Hz) of the second oscillation is separated from the peak frequency (400 Hz) of the first oscillation by a predetermined range or more, torque adjustment unit 140 sets the notch frequency of second notch filter 142 to a frequency (720 Hz) 9 times the peak frequency (800 Hz) of the oscillation. This allows the peak frequency (800 Hz) of the second oscillation to be attenuated after second notch filter 142 is set. Here, the constant separation or more means that the peak frequencies of the two oscillations are separated from the notch frequency by 2 times or more, for example.
In the auto-tuning, after the first notch filter 141 is set, a test operation is performed by increasing the gain of the first notch filter 141, and when it is possible to confirm that there is no oscillation in which the peak value in the FFT analysis result of the torque value obtained from the feedback signal exceeds a certain reference level, the tuning operation is ended. In the case where the second oscillation is present during the test operation of first notch filter 141 as shown in fig. 2B, second notch filter 142 is set to a frequency of 9 (720 Hz) which is the peak frequency (800 Hz) of the second oscillation, and then the test operation is performed by increasing the gain of second notch filter 142, and when it is confirmed that there is no oscillation whose peak exceeds a certain reference level, the tuning operation is terminated.
Next, fig. 3A shows a case where there are two vibrations due to oscillation of the servo amplifier 100, and the peak frequencies of the two vibrations are close (within a certain range). By within a certain range is meant that e.g. the peak frequencies of the two oscillations are within the frequency band of the notch frequency.
As shown in fig. 3A, when the peak frequencies of the two oscillations are close to each other, the torque adjustment unit 140 sets the notch frequency of the first notch filter 141 to a frequency (360 Hz) 9 times the peak frequency (400 Hz) of the oscillations. Thus, after the first notch filter 141 is set, the peak frequency (400 Hz) of the oscillation can be attenuated as shown by the broken line in fig. 3B.
Here, the test operation is performed by increasing the gain of the first notch filter 141. As shown in fig. 3B, if the vibration close to the peak frequency (400 Hz) is not attenuated as a result of FFT analysis of the torque value obtained from the feedback signal, torque adjustment unit 140 makes the strength of first notch filter 141 stronger than the initial setting as shown in fig. 3C. As a result, as shown by the solid line in fig. 3B, the depth of the notch frequency is increased, and the peak frequency of the oscillation close to (within a certain range) the peak frequency (400 Hz) of the oscillation can be covered and attenuated.
In addition, when the peak frequencies of the two oscillations due to the oscillation of the servo amplifier 100 are close to each other (within a certain range), it is also conceivable to set the notch frequency of the first notch filter 141 to be lower than the peak frequency of the oscillation. However, if the first notch filter 141 is set to be lower than the peak frequency of oscillation, the notch frequency may not cover the peak frequency of high oscillation even when the depth of the notch frequency is deep. Therefore, it is preferable to align the first notch filter 141 with the peak frequency side where the oscillation is high.
Next, referring to fig. 4, the auto-tuning process of the motor control device M will be described. In addition, the following description deals with a case of vibration reduction by torque adjustment.
(step S101)
The servo amplifier 100 analyzes the vibration level.
In this case, the servo amplifier 100 performs, for example, FFT analysis on the feedback signal to extract the vibration frequency.
(step S102)
The servo amplifier 100 determines whether or not there is vibration at a level equal to or higher than a predetermined reference level.
In this case, when the peak value of the extracted oscillation frequency does not exceed a certain reference level, the servo amplifier 100 determines that there is no oscillation equal to or higher than the certain reference level (no in step S102), and ends the process.
On the other hand, as shown in fig. 2A to 3C, when the peak value of the extracted oscillation frequency exceeds a predetermined reference level, the servo amplifier 100 determines that there is oscillation at a predetermined reference level or higher (yes in step S102), and the process proceeds to step S103.
(step S103)
The servo amplifier 100 determines whether or not there are two or more vibrations.
In this case, the servo amplifier 100 proceeds to step S107 when it is determined that the vibration is one (step S103: NO) as shown in FIG. 2A according to the determination result of step S107.
On the other hand, if the servo amplifier 100 determines that the number of vibrations is two or more (yes in step S103) as shown in FIG. 2B based on the determination result in step S102, the process proceeds to step S104.
(Steps S104 and S107)
The servo amplifier 100 sets the first notch filter 141.
In this case, as shown in fig. 2A, torque adjustment unit 140 of servo amplifier 100 sets the notch frequency of first notch filter 141 to a frequency (360 Hz) 9 times the peak frequency (400 Hz) of oscillation.
After the first notch filter 141 is set, a test operation is performed by increasing the gain of the first notch filter 141, and it is checked whether or not the oscillation having the peak frequency (400 Hz) at which the first notch filter 141 is set is attenuated.
When the setting of first notch filter 141 is ended and the vibration attenuation is confirmed in step S107, the process is ended.
(step S105)
The servo amplifier 100 determines whether the peak frequency of the second vibration is within a certain range.
In this case, as shown in fig. 3A, when the servo amplifier 100 determines that the peak frequency of the second vibration is within (close to) a certain range with respect to the peak frequency (400 Hz) of the first vibration (step S105: yes), the process proceeds to step S106.
On the other hand, as shown in fig. 2B, if the servo amplifier 100 determines that the peak frequency (800 Hz) of the second vibration is equal to or higher than the peak frequency (400 Hz) of the first vibration by a predetermined range (no in step S105), the process proceeds to step S108.
(step S106)
The servo amplifier 100 sets the second notch frequency.
In this case, as shown in fig. 2C, torque adjustment unit 140 of servo amplifier 100 sets the notch frequency of second notch filter 142 to a frequency (720 Hz) 9 with respect to the peak frequency (800 Hz) of the second oscillation.
After second notch filter 142 is set, a test operation is performed by increasing the gain of second notch filter 142, and it is checked whether or not the oscillation at the peak frequency (800 Hz) at which second notch filter 142 is set is attenuated.
(step S108)
The servo amplifier 100 enhances the strength of the first notch filter 141.
In this case, as shown in fig. 3C, torque adjustment unit 140 of servo amplifier 100 sets the strength of first notch filter 141 stronger than the initial setting.
Thus, by increasing the depth of the notch frequency of first notch filter 141, the peak frequency of the oscillation having a notch frequency close to (within a certain range) the peak frequency of the oscillation (400 Hz) can be covered and attenuated after first notch filter 141 is set.
(step S109)
The servo amplifier 100 determines whether the setting is completed.
In this case, servo amplifier 100 determines that the setting is not complete if it cannot be confirmed in step S104, step S106, and step S107 that the vibration of the peak frequencies (400 Hz and 800Hz, or 400 Hz) is attenuated due to the setting of first notch filter 141 and/or second notch filter 142 (step S109: no).
On the other hand, if it can be confirmed in step S104, step S106, and step S107 that the oscillation of the peak frequency (400 Hz and 800Hz, or 400 Hz) is attenuated by the setting of the first notch filter 141 and/or the second notch filter 142 (yes in step S109), the servo amplifier 100 determines that the setting is completed, and ends the processing.
In the above description, the first notch filter 141 and/or the second notch filter 142 are set and the gain increase of the first notch filter 141 and/or the second notch filter 142 is increased to perform the test operation in step S104, step S106, and step S107, but the present invention is not limited to this example. For example, after setting first notch filter 141 and/or second notch filter 142 in steps S104, S106, and S107, a test operation may be performed by increasing the gain of first notch filter 141 and/or second notch filter 142 in step S109 to check whether or not the oscillation of the peak frequency of first notch filter 141 and/or second notch filter 142 is attenuated, and whether or not the setting is completed may be determined.
In this way, in the present embodiment, servo amplifier 100 that adjusts the gain of motor 300 analyzes the feedback signal, and when it is determined that there is vibration equal to or greater than a certain reference level, torque adjustment unit 140 increases the intensity of notch filter 141 to be higher than the initial setting when the peak frequencies of adjacent vibrations determined by servo amplifier 100 are within a certain range, so that the peak frequencies of vibrations within the certain range are covered and attenuated. This can suppress the control from becoming unstable.
Description of the reference symbols
100. Servo amplifier
110. Position adjusting part
120. Feedforward control part
130. Feedback control unit
140. Torque adjustment unit
141. First notch filter
142. Second notch filter
150. Subtracter
160. Addition and subtraction device
170. Current control unit
300. Motor with a stator having a stator core
M motor control means.
Claims (5)
1. A motor control device is characterized by comprising:
a servo amplifier that adjusts a gain of the motor; and
a torque adjusting unit having a notch filter,
the servo amplifier analyzes the feedback signal to determine whether there is vibration above a certain reference level,
the torque adjusting unit may set the intensity of the notch filter to be stronger than the initial setting when the peak frequency of the adjacent oscillation determined by the servo amplifier is within a predetermined range.
2. The motor control apparatus of claim 1,
the torque adjustment unit sets the notch filter to a frequency smaller than a peak frequency of the oscillation by a predetermined ratio when the servo amplifier determines that the oscillation is present.
3. The motor control apparatus of claim 1,
the torque adjustment unit sets the notch filter on a peak frequency side where the adjacent oscillations are high.
4. A motor control method is characterized in that,
analyzing the feedback signal by a servo amplifier for adjusting the gain of the motor, judging whether there is vibration above a certain reference level,
the torque adjusting unit having a notch filter makes the intensity of the notch filter stronger than the initial setting when the peak frequencies of the adjacent oscillations determined by the servo amplifier are within a predetermined range.
5. The motor control method according to claim 4,
when the servo amplifier determines that the oscillation is present, the notch filter is set by the torque adjustment unit to a frequency that is smaller than a peak frequency of the oscillation by a predetermined ratio.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2021-119845 | 2021-07-20 | ||
| JP2021119845A JP2023015827A (en) | 2021-07-20 | 2021-07-20 | Motor control device and motor control method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115706551A true CN115706551A (en) | 2023-02-17 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210850484.3A Pending CN115706551A (en) | 2021-07-20 | 2022-07-19 | Motor control device and motor control method |
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| Country | Link |
|---|---|
| JP (1) | JP2023015827A (en) |
| CN (1) | CN115706551A (en) |
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- 2021-07-20 JP JP2021119845A patent/JP2023015827A/en active Pending
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- 2022-07-19 CN CN202210850484.3A patent/CN115706551A/en active Pending
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