JP4717488B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device that drives and controls a mechanical device having mechanical resonance, and more particularly to a motor control device when the mechanical device has a plurality of mechanical resonances.

  As a motor control device for driving and controlling a mechanical device having mechanical resonance, for example, the one disclosed in Patent Document 1 is known. Hereinafter, the outline will be described with reference to FIG. FIG. 4 is a block diagram illustrating a configuration example of a conventional motor control device.

  In FIG. 4, the drive shaft of the mechanical device 20 that is a load is connected to the rotation shaft of the motor 1. The motor 1 is equipped with speed detection means 3 for detecting the motor speed Va. The motor speed Va detected by the speed detection means 3 is given to the speed control means 4 and the frequency estimation means 7. A notch filter 5 and a torque control means 6 are arranged in series between the speed control means 4 and the motor 1.

  The speed control means 4 outputs a torque command τ 1 for controlling the deviation between the external speed command Vr and the motor speed Va to zero, to the notch filter 5. The notch filter 5 can change the notch frequency ωn, and outputs a new torque command τ2 obtained by removing the frequency component of the notch frequency ωn from the input torque command τ1 to the torque control means 6. The torque control means 6 drives the motor 1 by controlling the motor torque in accordance with the input torque command τ2.

  Here, when the control system enters an oscillation state due to mechanical resonance of the mechanical device 20, the motor 1 vibrates at the oscillation frequency, and the motor speed Va detected by the speed detection means 3 is The vibration component is included. Therefore, the frequency estimation means 7 estimates the frequency of the vibration component included in the motor speed Va detected by the speed detection means 3, sets the estimated frequency as the notch frequency ωn in the notch filter 5, The notch frequency ωn is matched with the resonance frequency of the mechanical device.

  As a result, when the control system is oscillated due to the mechanical resonance of the mechanical device 20, the frequency component of the mechanical resonance is removed by the notch filter 5, so that the mechanical resonance is suppressed and stable control is performed. .

  In this configuration, when the mechanical resonance frequency deviates from the notch frequency ωn of the notch filter 5 set as described above due to some cause such as aging of the mechanical device 20, the mechanical resonance cannot be suppressed by the notch filter 5. The control loop enters an oscillation state. However, when the control loop enters the oscillation state, the frequency estimation means 7 immediately estimates the oscillation frequency and sets the estimated frequency in the notch filter 5, so that the notch frequency ωn again matches the mechanical resonance frequency. Thus, mechanical resonance is suppressed, and stable control can be restored.

JP 2003-52188 A

  However, the above-described conventional motor control device is effective when the mechanical device has only one mechanical resonance, but has only one set of notch filters and frequency estimation means, so that a plurality of mechanical devices There is a problem that it cannot cope with a mechanical device having resonance.

  Further, since the notch filter has a characteristic of delaying the phase, the phase characteristic of the control loop changes when the notch frequency of the notch filter is changed. Therefore, in the conventional motor control device described above, if the notch frequency is changed carelessly, the control loop becomes unstable due to the change in the phase characteristics, and there is a possibility that the oscillation state is different from the mechanical resonance.

  The present invention has been made in view of the above, and even when a mechanical device has a plurality of mechanical resonances, it is possible to suppress each oscillation caused by the plurality of mechanical resonances, and for some reason such as secular change. An object of the present invention is to obtain a motor control device capable of stably and automatically changing the notch frequency of a notch filter even when the resonance frequency of the notch filter changes.

To achieve the above object, the present invention is the motor control device for driving and controlling the machine in a motor oscillation caused by mechanical resonance while suppressed by the notch filter of the machinery, the mechanical resonance of the mechanical device Frequency estimation means for estimating the oscillation frequency when oscillation caused by this occurs, and when the mechanical device has a plurality of mechanical resonances, a plurality of oscillations caused by the plurality of mechanical resonances are suppressed in a one-to-one relationship a Subeku corresponding plurality of notch filters arranged in series in the supply line of the drive command notch frequency is set to the motor, with each, it is possible to change the set notch frequency, mechanical a plurality of notch filters which can be set by switching to enable or disable the filter function determined according to the characteristics of the resonance, the estimated of at said frequency estimation means A notch filter selection means for selecting one of said plurality of notch filters based on the frequency and with the notch frequency set in the valid or invalid configuration state and each notch filter of each notch filter, the notch And notch frequency setting means for changing and setting the notch frequency of one notch filter selected by the filter selection means to the frequency estimated by the frequency estimation means.

According to the present invention, Runode comprises a plurality of notch filters for a plurality of mechanical resonance, it is respectively appropriately suppress even mechanical device the oscillation due to the mechanical resonance with multiple mechanical resonance it can. Then, when any one mechanical resonance is changed due to secular change or the like and the oscillation caused by the changed mechanical resonance occurs, the estimated oscillation frequency, the valid / invalid setting state of each notch filter, and the notch frequency are set. Since an appropriate one is selected from a plurality of notch filters and the notch frequency is reset, oscillation caused by each mechanical resonance changed due to secular change or the like can be appropriately suppressed.

According to the present invention, even when the mechanical device has a plurality of mechanical resonances, each oscillation caused by the plurality of mechanical resonances can be suppressed , and the resonance frequency of the mechanical device changes due to some cause such as secular change. But there is an effect that a change of the notch frequency of the notch filter Ru can be performed stably and automatically.

  Exemplary embodiments of a motor control device according to the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG.
1 is a block diagram showing a configuration of a motor control apparatus according to Embodiment 1 of the present invention. As shown in FIG. 1, the motor control device according to the first embodiment is provided with a mechanical device 2 having a plurality of mechanical resonances in place of the mechanical device 20 in the configuration shown in FIG. 4 (conventional example). Yes. The notch filter 5 shown in FIG. 4 is replaced with a series circuit of a plurality of notch filters (three in the illustrated example, notch filters 5a, 5b and 5c), and the notch filter selecting means 8 and the notch frequency setting means. 9 is added.

  The notch filters 5a, 5b, and 5c arranged in series can change and set the notch frequency ωn in the same manner as the notch filter 5 shown in FIG. 4, but in addition, the filter function is enabled and disabled. It can be set by switching to the state. That is, each of the notch filters 5a, 5b, and 5c outputs the input signal as it is when the filter function is in an invalid state, and outputs the signal component of the notch frequency set from the input signal when the filter function is in an effective state. It is designed to be removed and output.

  The notch filter selection means 8 selects one of the notch filters 5a, 5b, 5c based on the frequency ωe estimated by the frequency estimation means 7. When it cannot be selected, an alarm signal is output to the outside.

  The notch frequency setting means 9 is provided between the notch filters 5a, 5b, 5c and the frequency estimation means 7. The notch frequency ωn of the notch filter selected by the notch filter selection means 8 is estimated by the frequency estimation means 7. It is supposed to be set to.

  Next, the operation of the part related to the first embodiment will be described. Here, it is assumed that the mechanical device 2 having a plurality of mechanical resonances has mechanical resonances at, for example, 400 Hz, 600 Hz, and 800 Hz. It is assumed that the mechanical resonance at 400 Hz and 600 Hz has a small attenuation rate, and the mechanical resonance at 800 Hz has a large attenuation rate.

  For mechanical resonance with a small attenuation factor, the control loop tends to oscillate at that frequency, so it is necessary to suppress oscillation due to the resonance with a notch filter. Therefore, a notch frequency of 400 Hz is set in the notch filter 5a, and a notch frequency of 600 Hz is set in the notch filter 5b, thereby suppressing oscillation caused by mechanical resonance. On the other hand, since it is difficult for the control loop to oscillate at the frequency with respect to the mechanical resonance having a large attenuation rate, it is not necessary to suppress it actively. For this reason, the notch filter 5c is kept in an invalid state.

  Here, the notch filter selection means 8 manages the valid / invalid state and the notch frequency set as described above for each notch filter, and controls even if the set notch frequency is changed. A predetermined frequency range defined as a range in which the loop does not become unstable is managed. Strictly speaking, the predetermined frequency range can be determined as a range in which the control loop does not become unstable by examining changes in the control loop phase characteristics when the notch frequency changes. Further, the range in which the control loop does not become unstable may be searched by actually changing the notch frequency, or may be determined by an empirical rule.

  In the following description, the predetermined frequency range of each notch filter is set to ± 10% of the set notch frequency. In the above example, the predetermined frequency range of the notch filter 5a is 360 Hz to 440 Hz, and the predetermined frequency range of the notch filter 5b is 540 Hz to 660 Hz. This is used by the notch filter selection means 8 as a decision material for selecting the notch filter.

  In FIG. 1, it is assumed that the mechanical resonance frequency of 400 Hz has changed to 370 Hz for some reason. Since the notch frequency set in the notch filter 5a is 400 Hz and deviates from the mechanical resonance frequency (370 Hz), the notch filter 5a cannot suppress oscillation caused by the mechanical resonance.

  Therefore, oscillation due to mechanical resonance at 370 Hz occurs and the motor 1 vibrates. The vibration of the motor 1 is detected by the speed detection means 3, and a motor speed Va including a frequency component of 370 Hz is output. The frequency estimation means 7 estimates the oscillation frequency based on the motor speed Va detected by the speed detection means 3 and outputs a frequency value of ωe = 370 Hz.

  Therefore, the notch filter selection means 8 compares the frequency (ωe = 370 Hz) estimated by the frequency estimation means 7 with the notch frequency set for each notch filter, and the estimated frequency (ωe = 370 Hz) is compared. Select a notch filter within the specified frequency range. In the present example, since the predetermined frequency range of the notch filter 5a is 360 Hz to 440 Hz, the notch filter 5a is selected.

  Next, the notch frequency setting means 9 sets the frequency (ωe = 370 Hz) estimated by the frequency estimation means 7 to the notch filter 5a selected by the notch filter selection means 8. As a result, the notch frequency of the notch filter 5a again coincides with the resonance frequency (370 Hz) of the mechanical device, and oscillation due to mechanical resonance is suppressed.

  As described above, according to the first embodiment, a plurality of notch filters are provided, and when oscillation caused by mechanical resonance occurs, the estimated oscillation frequency, the setting state of each notch filter valid / invalid, and the notch frequency Since an appropriate one is selected from a plurality of notch filters and the notch frequency is reset, even a mechanical device having a plurality of mechanical resonances can appropriately suppress oscillation caused by the mechanical resonance. Can do.

  At this time, a predetermined frequency range, which is a range in which the control loop does not become unstable even if the already set notch frequency is changed, is determined in advance, and the notch filter selection unit determines the oscillation frequency estimated by the frequency estimation unit. Is compared with the notch frequency set for each notch filter, and the notch filter whose estimated oscillation frequency is within the predetermined frequency range is selected, and the newly set notch frequency is within the predetermined frequency range. Since it is limited, the phase characteristics of the control loop do not change greatly and become unstable, and stable control can be maintained.

Embodiment 2. FIG.
FIG. 2 is a block diagram showing a configuration of a motor control apparatus according to Embodiment 2 of the present invention. As shown in FIG. 2, the motor control apparatus according to the second embodiment is provided with notch filter selection means 10 in place of notch filter selection means 8 in the configuration shown in FIG. 1 (Embodiment 1). Yes.

  The notch filter selection means 10 compares the oscillation frequency ωe estimated by the frequency estimation means 7 with the notch frequency ωn set for each notch filter, and there is a notch filter whose difference falls within the predetermined frequency range. If not, the notch filter is selected, and if not, the notch filter in an invalid state is selected.

  Next, the operation of the part related to the second embodiment will be described. Assume that the mechanical device 2 having a plurality of mechanical resonances has mechanical resonances at 400 Hz, 600 Hz, and 800 Hz as in the first embodiment. The mechanical resonance at 400 Hz and 600 Hz has a small attenuation rate, and the mechanical resonance at 800 Hz has a large attenuation rate.

  Similarly to the first embodiment, it is assumed that the notch filter 5a and the notch filter 5b have the notch frequencies set to 400 Hz and 600 Hz, respectively, and the notch filter 5c is in an invalid state.

  In the second embodiment, the operation when the attenuation factor of the mechanical resonance at 800 Hz becomes small due to secular change or the like will be described. Oscillation is unlikely to occur when the mechanical resonance attenuation factor is large, whereas oscillation tends to occur when the attenuation factor is small. When oscillation due to mechanical resonance at 800 Hz occurs due to the decrease in the attenuation factor, the motor 1 vibrates and the frequency estimation means 7 sets the oscillation frequency (ωe = 800 Hz) as described in the first embodiment. presume.

  In response to this, the notch filter selection means 10 searches for the notch filter whose oscillation frequency (ωe = 800 Hz) is within the predetermined frequency range from the three notch filters 5a, 5b, 5c. There is no notch filter. Therefore, the notch filter selection means 10 selects the notch filter 5c in an invalid state. The notch frequency setting means 9 sets the notch frequency ωn of the notch filter 5c to 800 Hz. As a result, oscillation caused by the newly generated 800 Hz mechanical resonance is suppressed, so that stable control is maintained.

  As can be understood from the above description, when there is no notch filter in an invalid state, it is impossible to suppress oscillation caused by newly generated mechanical resonance. In such a case, the notch filter selection means 10 promptly outputs an alarm signal to the outside. As a result, safe measures such as stopping the motor 1 can be taken quickly.

  As described above, according to the second embodiment, the notch filter selection unit compares the oscillation frequency estimated by the frequency estimation unit with the notch frequency already set in each notch filter, and the difference is a predetermined frequency. When there is a notch filter that falls within the range, the notch filter is selected, and when it does not exist, the notch filter that is in an invalid state is selected. Even when oscillation occurs, oscillation due to the new mechanical resonance can be suppressed appropriately.

  And, in the notch filter selection means, when there is no notch filter to be selected and oscillation due to mechanical resonance cannot be suppressed, an alarm signal is output, so that the machine device is stopped by the alarm signal, etc. Safe measures can be taken.

Embodiment 3 FIG.
FIG. 3 is a block diagram showing a configuration of a motor control apparatus according to Embodiment 3 of the present invention. As shown in FIG. 3, in the motor control apparatus according to the third embodiment, in the configuration shown in FIG. 1 (Embodiment 1), notch filter selection means 11 is provided instead of notch filter selection means 8, and A notch frequency setting means 12 is provided instead of the notch frequency setting means 9.

  The notch filter selection means 11 manages the first predetermined frequency range defined for each notch filter, and the frequency newly estimated by the frequency estimation means 7 among the notch filters in the valid state is the first frequency range. The notch filter that falls within the predetermined frequency range is selected.

  The notch frequency setting means 12 manages a second predetermined frequency range narrower than the first predetermined frequency range defined for each notch filter, and the notch filter selected by the notch filter selection means 11 is in an effective state. In this case, the second predetermined frequency range of the selected notch filter is compared with the oscillation frequency ωe newly estimated by the frequency estimation means 7, and the newly estimated oscillation frequency ωe is compared with the second predetermined frequency range. When the frequency is out of the predetermined frequency range, the newly set notch frequency is corrected so that the difference between the already set notch frequency and the newly set notch frequency is within the second predetermined frequency range. The notch filter is configured to be set.

  Next, the operation of the part related to the third embodiment will be described. Assume that the mechanical device 2 having a plurality of mechanical resonances has mechanical resonances at 400 Hz, 600 Hz, and 800 Hz, as in the first embodiment. It is assumed that the mechanical resonance at 400 Hz and 600 Hz has a small attenuation rate, and the mechanical resonance at 800 Hz has a large attenuation rate. Similarly to the first embodiment, it is assumed that the notch filter 5a and the notch filter 5b have the notch frequencies set to 400 Hz and 600 Hz, respectively, and the notch filter 5c is in an invalid state.

  The effect of suppressing oscillation due to mechanical resonance by the notch filter is maximized when the notch frequency exactly matches the resonance frequency of the mechanical device, but a certain degree of resonance suppression effect can be obtained even if the notch frequency slightly deviates. It is done. Therefore, in the third embodiment, when the notch filter is in an effective state, that is, the notch frequency in which the notch frequency is set in order to suppress oscillation due to mechanical resonance in the first and second embodiments. In the filter, when the frequency of the mechanical resonance subsequently changes, considering the controllability, first, the notch filter is selected by the notch filter selection means 11 using the first predetermined frequency range, and this is the target. Thus, the notch frequency setting means 12 uses the second predetermined frequency range to set a notch frequency slightly deviated from the new resonance frequency.

  That is, the second predetermined frequency range is determined as a range in which the control loop does not become unstable even when the set notch frequency is changed. Strictly speaking, it can be determined as a range in which the control loop does not become unstable by examining the change in the control loop phase characteristic when the notch frequency changes. Further, the range in which the control loop does not become unstable may be searched by actually changing the notch frequency, or may be determined by an empirical rule. This determination method is the same as the predetermined frequency range in the first embodiment. In the present example, since the notch filters in the effective state are the notch filters 5a and 5b, the second predetermined frequency range of the notch filter 5a is 360 Hz to 440 Hz, and the second predetermined frequency range of the notch filter 5b is 540 Hz. ˜660 Hz.

  The first predetermined frequency range is set to a frequency range expanded from the second predetermined frequency range by a range in which the resonance suppression effect can be obtained. For example, when the second predetermined frequency range is expanded by 5% and the first predetermined frequency range is set to ± 15% of the set notch frequency, the first predetermined frequency range of the notch filter 5a is 340 Hz. 460 Hz, and the first predetermined frequency range of the notch filter 5b is 510 Hz to 690 Hz.

  Now, suppose that the mechanical resonance frequency which was 400 Hz at the beginning changed to 350 Hz for some reason. Since the current mechanical resonance frequency (ωe = 350 Hz) deviates from the 400 Hz notch frequency set in the notch filter 5a, oscillation due to mechanical resonance occurs and the motor 1 vibrates. The vibration of the motor 1 is detected by the speed detection means 3. The frequency estimation means 7 estimates the oscillation frequency ωe based on the motor speed Va detected by the speed detection means 3 and outputs a frequency value of ωe = 350 Hz.

  Then, the notch filter selection unit 11 compares the frequency (ωe = 350 Hz) estimated by the frequency estimation unit 7 with the frequency set for each notch filter in the effective state, and estimates the frequency (ωe). = 350 Hz) is selected within the first predetermined frequency range. In the present example, since the first predetermined frequency range of the notch filter 5a is 340 Hz to 460 Hz, the notch filter 5a is selected.

  Then, the frequency setting means 12 includes the second predetermined frequency range (360 Hz to 440 Hz) of the notch filter 5a selected by the notch filter selection means 11 and the frequency estimated by the frequency estimation means 7 (ωe = 350 Hz). Compare In this example, since the frequency (ωe = 350 Hz) estimated by the frequency estimation means 7 is outside the second predetermined frequency range (360 Hz to 440 Hz) of the notch filter 5a, the newly set notch frequency ωn Is limited to the second predetermined frequency range (360 Hz to 440 Hz), and the notch frequency ωn of the notch filter 5a is corrected and set to ωn = 360 Hz.

  As described above, when the mechanical resonance frequency, which was initially 400 Hz, is changed to 350 Hz for some reason, the notch frequency is changed to 360 Hz which is shifted by 10 Hz instead of 350 Hz. can get. At this time, the change range of the notch frequency is 40 Hz in the above example, which falls within the second predetermined frequency range (360 Hz to 440 Hz). That is, since the second predetermined frequency range is determined so that the control loop does not become unstable, even if the notch frequency is changed within the second predetermined frequency range, the phase characteristic of the control loop changes greatly. In this way, it is possible to prevent the control loop from becoming unstable.

  When the new oscillation frequency ωe is greatly deviated from the frequency in the second predetermined frequency range, the notch frequency ωn of the notch filter that has been in charge of suppression is changed to the second predetermined frequency range by the notch frequency setting means 12. However, the difference between the oscillation frequency ωe and the notch frequency ωn becomes large and the resonance suppression effect by the notch filter cannot be expected. First, as described above, the oscillation frequency ωe is determined so that the resonance suppression effect can be obtained. A notch filter that can fall within a certain first predetermined frequency range is selected, and the notch frequency ωn of the notch filter is corrected to be within the second predetermined frequency range, so that a resonance suppression effect can be obtained. .

  As described above, according to the third embodiment, the second predetermined frequency range in which the stability of the control loop can be ensured even if the notch frequency is changed, and the resonance suppression effect can be expected although it is slightly wider than that. When the mechanical resonance frequency changes from the original frequency, first, an appropriate one is selected from a plurality of notch filters in an effective state using the first predetermined frequency range, Since the notch frequency of the selected notch filter is corrected so as to fall within the second predetermined frequency range, oscillation caused by the changed mechanical resonance can be suppressed while maintaining the stability of the control loop.

  As described above, the motor control device according to the present invention is suitable for driving and controlling a machine device such as a machine tool or a general industrial automatic machine, particularly a machine device having a plurality of machine resonances.

It is a block diagram which shows the structure of the motor control apparatus by Embodiment 1 of this invention. It is a block diagram which shows the structure of the motor control apparatus by Embodiment 2 of this invention. It is a block diagram which shows the structure of the motor control apparatus by Embodiment 3 of this invention. It is a block diagram which shows the structural example of the conventional motor control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Mechanical apparatus 3 Speed detection means 4 Speed control means 5a, 5b, 5c Notch filter 6 Torque control means 7 Frequency estimation means 8 Notch filter selection means 9 Notch frequency setting means 10 Notch filter selection means 11 Notch filter selection means 12 Notch Frequency setting means

Claims (5)

In a motor control device that drives and controls the mechanical device with a motor while suppressing oscillation due to mechanical resonance of the mechanical device with a notch filter,
Frequency estimation means for estimating the oscillation frequency when oscillation due to mechanical resonance of the mechanical device occurs;
When the mechanical device has a plurality of mechanical resonances, a corresponding notch frequency is set to suppress a plurality of oscillations caused by the plurality of mechanical resonances in a one-to-one relationship, and a drive command is supplied to the motor A plurality of notch filters arranged in series in the line, each of which can change the set notch frequency, and can be set by switching enable / disable of the filter function determined according to the mechanical resonance characteristics Multiple notch filters that can
Selecting one of said plurality of notch filters based on said notch frequency set in the valid or invalid configuration state and each notch filter of each notch filter and the estimated frequency by said frequency estimation means Notch filter selection means;
A motor control device comprising: notch frequency setting means for changing and setting the notch frequency of one notch filter selected by the notch filter selection means to the frequency estimated by the frequency estimation means.   The notch filter selection means manages a predetermined frequency range determined for each notch filter, compares the oscillation frequency estimated by the frequency estimation means and the notch frequency set for each notch filter, 2. The motor control device according to claim 1, wherein when there is a notch filter whose difference falls within the predetermined frequency range, the notch filter is selected.   The notch filter selection means manages a predetermined frequency range determined for each notch filter, compares the oscillation frequency estimated by the frequency estimation means and the notch frequency set for each notch filter, 2. The notch filter is selected when there is a notch filter in which the difference falls within the predetermined frequency range, and the notch filter in an invalid state is selected when the notch filter does not exist. Motor control device. The notch filter selection means manages a first predetermined frequency range defined for each notch filter, and the frequency estimated by the frequency estimation means among the notch filters in an effective state is the first frequency range. Select a notch filter that fits within the specified frequency range,
The notch frequency setting means manages a second predetermined frequency range narrower than the first predetermined frequency range defined for each notch filter, and the notch filter selected by the notch filter selecting means is effective. If the oscillation frequency estimated by the frequency estimation means is outside the second predetermined frequency range of the selected notch filter , the notch already set in the selected notch filter claims the difference between the notch frequency set frequency and new troughs and sets to the second and correct the notch frequency to be newly set the selected notch filter so as to be within a predetermined frequency range Item 2. The motor control device according to Item 1. The second predetermined frequency range is defined as a frequency range in which the control loop does not become unstable even if the notch frequency of each notch filter is changed,
The first predetermined frequency range is a frequency obtained by expanding the second predetermined frequency range within a range in which a resonance suppression effect can be obtained even when the notch frequency of each notch filter is limited to the second predetermined frequency range. The motor control device according to claim 4, wherein the motor control device is defined in a range.

Images