JP5467874B2 - Resonance suppression device and resonance suppression method - Google Patents

Description

  The present invention relates to an adaptive notch filter whose filter coefficient can be adjusted, and a resonance suppression apparatus using the adaptive notch filter.

  For example, Patent Document 1 discloses a resonance frequency detection device for an electric motor control device in which a swept sine wave signal is input to an electric motor control system, and the frequency of the swept sine wave signal that maximizes the absolute value of the signal of the detection means is the resonance frequency. Have been described. In Patent Document 2, the detection speed or the detection position is filtered by each of the directional filter and the second notch filter, and the first notch filter is output according to the product of the output of the directional filter and the output of the second notch filter. The correction of the notch center frequency is described.

JP 2003-134868 A JP 2004-274976 A

  However, in the method of obtaining the resonance frequency by the swept sine wave signal, it is necessary to apply the swept sine wave signal to the control system, and therefore it is not always easy to update the resonance frequency sequentially. That is, the use of the swept sine wave signal itself is a limitation in application to a desired control system. Further, the method using the directional filter and the second notch filter requires two filter processes, so that the calculation amount is large. When the notch center frequency is sequentially updated, it is preferable that the amount of calculation required for each update is as small as possible.

  Therefore, an object of the present invention is to provide an adaptive notch filter that can automatically update the center frequency with a small calculation load and a resonance suppression device using the adaptive notch filter.

  An adaptive notch filter according to an aspect of the present invention is capable of changing a center frequency and suppressing a natural frequency component of a control target included in a signal for generating a control input to the control target that may cause resonance. A variable filter having a phase characteristic corresponding to a magnitude relationship between a frequency of an input signal and a current value of the center frequency, and a signal derived from a control output of the control target as the input signal, A center frequency correction amount defined using the input signal and output signal of the variable filter is calculated so that the sign of the average value of the center frequency correction amount is determined according to the magnitude relationship, and based on the center frequency correction amount A correction operation unit that updates the center frequency.

  According to this aspect, the magnitude relationship between the frequency of the input signal to the variable filter and the current value of the center frequency is associated with the average value of the center frequency correction amount via the phase shift of the output signal from the variable filter. . Therefore, the center frequency can be updated according to the magnitude relationship between the frequency of the input signal to the variable filter and the current value of the center frequency. The updated center frequency can suppress the natural frequency component included in the signal for generating the control input to the control target that may cause resonance. Further, since the output signal processed by the variable filter and the unprocessed input signal are used, the center frequency can be updated with a relatively small calculation load.

  Another aspect of the present invention is a method of updating a center frequency of a notch filter for suppressing a natural frequency component of a control target included in a signal for generating a control input to the control target that may cause resonance. is there. In this method, the input signal derived from the control output is filtered by a variable filter having a phase characteristic corresponding to the magnitude relationship between the frequency of the input signal and the current value of the center frequency, and according to the magnitude relationship. Calculating a center frequency correction amount defined using the input signal and the output signal of the variable filter so that a sign of an average value of the center frequency correction amount is determined.

  An adaptive notch filter according to another aspect of the present invention has a notch filter capable of changing a center frequency, a phase characteristic that changes monotonously in a local frequency region including a current value of the center frequency, and a peak in the current value. A variable filter having an amplitude characteristic, and an average value is linear in a wide band including the local frequency region, which depends on an output signal obtained by processing the input signal including the frequency component to be suppressed by the notch filter by the variable filter. And a correction calculation unit that calculates a center frequency correction amount that changes in a stepwise manner and updates the center frequency based on the center frequency correction amount.

  Another aspect of the present invention is a method for updating the center frequency of an adaptive notch filter. This method uses a variable filter having a phase characteristic that changes monotonously in a local frequency region including the current value of the center frequency and an amplitude characteristic that has a peak in the current value, and a frequency component to be suppressed by an adaptive notch filter. And calculating a center frequency correction amount that is dependent on the output signal of the variable filter and whose average value changes linearly in a wide band including the local frequency region.

  According to the present invention, the center frequency can be automatically updated with a relatively small amount of calculation.

It is a block diagram which shows the structure of the adaptive notch filter which concerns on one Embodiment of this invention. It is a figure which shows the example of the frequency characteristic of the notch filter which concerns on one Embodiment of this invention. It is a figure which shows the example of the frequency characteristic of the peak filter which concerns on one Embodiment of this invention. It is a figure which shows the relationship between the notch center frequency (omega) ₀ and the coefficient k which concern on one Embodiment of this invention. It is a figure which shows the principle of correction of notch center frequency (omega) _{0 which} concerns on one Embodiment of this invention as a frequency characteristic. It is a figure which shows the average value of the center frequency correction amount of the Example which uses a peak filter for a phase difference filter. It is a figure which shows the average value of the center frequency correction amount of the Example which uses an all-pass filter for a phase difference filter. It is a block diagram which shows the system configuration | structure of the resonance suppression apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the response of the control system shown in FIG.

  An adaptive notch filter according to an embodiment of the present invention includes a notch filter and a filter coefficient adjustment unit that adjusts a filter coefficient of the notch filter. The filter coefficient adjustment unit includes a variable filter and a correction calculation unit that corrects the filter coefficient of the notch filter based on the input and output of the variable filter. In this way, since the filter processing necessary for correcting the filter coefficient can be performed once, the filter coefficient can be adjusted with a small calculation load. Since the calculation load is small, the filter coefficient can be updated frequently with a short calculation cycle.

  In one embodiment, the filter coefficient adjustment unit updates the center frequency of the notch filter based on the input and output of the variable filter. The filter coefficient adjustment unit updates the filter coefficients other than the center frequency (for example, the gain at the center frequency and the bandwidth of the notch) by calculating using the update value of the center frequency. In addition to the center frequency, the filter coefficient adjustment unit may update only the filter coefficient proportional to the center frequency. The filter coefficient adjustment unit may make the update frequency of filter coefficients other than the center frequency smaller than the update frequency of the center frequency. Alternatively, the filter coefficient adjustment unit may continue to use the initial value without updating filter coefficients other than the center frequency. In this way, the calculation load can be further reduced.

  The frequency phase characteristic of the variable filter is set so as to correspond to the magnitude relationship between the frequency of the input signal and the current value of the notch center frequency. That is, the magnitude relationship between the frequency of the input signal and the current value of the center frequency corresponds to the magnitude relationship between the phase shift of the output signal and the phase shift at the current value. The phase shift of the current value of the center frequency is referred to as a reference phase shift. When the input frequency component is in a frequency region larger than the current value, the output signal is given a phase shift larger (or smaller) than the reference phase shift. On the other hand, when the input frequency component is in a frequency region smaller than the current value, the output signal is given a phase shift smaller (or larger) than the reference phase shift.

  The correction calculation unit calculates a center frequency correction amount, and changes the center frequency based on the obtained center frequency correction amount. The center frequency correction amount is defined using the input signal and output signal of the variable filter so that the time average increases or decreases the center frequency according to the magnitude relationship between the phase shift of the output signal of the variable filter and the reference phase shift. Yes. For example, the center frequency correction amount is defined using the input signal and output signal of the variable filter so that the sign of the average value is determined according to the phase shift of the output signal of the variable filter. In this case, the correction amount is defined so that the average value of the center frequency correction amount becomes zero when the phase shift of the output signal matches the reference phase shift.

  In this way, the magnitude relationship between the frequency of the input signal to the variable filter and the current value of the center frequency is related to the average value of the center frequency correction amount via the phase shift of the output signal from the variable filter. That is, when the input frequency component is higher than the center frequency, the center frequency is increased by the correction amount on the average, and when the input frequency component is lower than the center frequency, the center frequency is decreased by the correction amount on the average. For example, in an embodiment in which an update value is obtained by adding the correction amount to the current center frequency value, the correction calculation unit sets the sign of the average value of the correction amount as positive when the input frequency component is greater than the center frequency, When the frequency component is smaller than the center frequency, the average value of the correction amount is negative. In this way, the center frequency can be updated according to the magnitude relationship between the frequency of the input signal to the variable filter and the current value of the center frequency.

  In one embodiment, the frequency phase characteristic of the variable filter may be set so as to give a phase shift according to the deviation between the frequency of the input signal and the current value of the center frequency. That is, the greater the difference between the input frequency component and the center frequency, the greater the difference between the phase shift of the output signal and the reference phase shift. At this time, as described above, the magnitude relationship between the input frequency component and the center frequency may be associated with the magnitude relationship between the phase shift of the output signal and the reference phase shift.

  The frequency amplitude characteristic of the variable filter may be set so that the current value of the center frequency has a gain peak. The variable filter preferably has an amplitude characteristic with a maximum peak at the current value of the center frequency. In this case, the center frequency correction amount may be defined such that the average value has a magnitude corresponding to the amplitude gain of the output signal of the variable filter.

  That is, the adaptive notch filter according to an embodiment includes a notch filter that can change a center frequency, a phase characteristic that gives a phase shift according to a deviation between a frequency of an input signal and a current value of the center frequency, and the current A variable filter having an amplitude characteristic having a peak in value, a correction operation for calculating a center frequency correction amount based on an input signal and an output signal of the variable filter, and changing the center frequency based on the center frequency correction amount May be provided.

  In this way, it is possible to generate a center frequency correction amount according to the deviation between the input frequency component and the center frequency. That is, the center frequency is greatly corrected as the frequency component to be suppressed by the notch filter deviates from the center frequency. If the input frequency component matches the center frequency, the influence of the frequency component having a large degree of deviation from the center frequency on the center frequency correction amount is small due to the amplitude characteristic having a peak at the current value of the center frequency. Therefore, the updated center frequency can be kept near the current value. It is also possible to reduce the influence of low frequency components in an input signal that usually has a large amplitude due to a control command or the like. In this way, the center frequency can be quickly converged to the frequency component to be suppressed.

  In a preferred embodiment, the correction calculation unit calculates a center frequency correction amount whose average value linearly changes in a wide band including a local frequency region including the current value of the center frequency. The local frequency region includes the current value of the center frequency and has an upper limit frequency and a lower limit frequency. The variable filter may have, for example, a phase characteristic that changes monotonously in the local frequency region and an amplitude characteristic that has a peak at the current center frequency value. The peak width may coincide with the local frequency region. The local frequency region is divided into a low frequency region from the lower limit frequency to the center frequency current value and a high frequency region from the center frequency current value to the upper limit frequency. The correction calculation unit may calculate a center frequency correction amount that is defined so as to take a code in which an average value of the center frequency correction amount differs between the low frequency region and the high frequency region. The center frequency correction amount may be defined in a format that depends on the product of the input signal and the output signal of the variable filter. The correction calculation unit updates the center frequency so as to converge to the natural frequency component to be controlled based on such a center frequency correction amount.

  The phase characteristic of the variable filter may be set such that the sign determination coefficient that determines the sign of the average value of the center frequency correction amount takes a positive value at one of the upper limit frequency and the lower limit frequency and takes a negative value at the other. The code determination coefficient may be in the form of a periodic function that varies with phase. In this case, the phase shift range corresponding to the local frequency region may be smaller than one cycle of the periodic function of the code determination coefficient. Preferably, the maximum value of the periodic function of the code determination coefficient may be taken at one of the upper limit frequency and the lower limit frequency of the local frequency region, and the minimum value may be taken at the other.

  In one embodiment, the variable filter has a phase characteristic that changes from a first phase shift to a second phase shift in a local frequency region that includes a current center frequency value, and an amplitude characteristic that has a peak at the current value. You may have. That is, the phase characteristic of the variable filter monotonously changes from the first phase shift to the second phase shift in the local frequency region including the center frequency current value, and between the first and second phase shifts at the current value. May be set to give the third phase shift. As the lower limit frequency, the center frequency current value, and the upper limit frequency and the frequency increase in the local frequency region, the phase shift changes monotonously continuously with the first phase shift, the third phase shift, and the second phase shift.

  The center frequency correction amount is such that the average value of the center frequency correction amount is represented by the product of the code determination coefficient that determines the sign according to the phase shift of the output signal from the variable filter and the sign invariant part where the sign is constant. May be defined. The sign determination coefficient is, for example, a positive maximum value in one of the first and second phase shifts, a negative minimum value in the other, and zero at the current center frequency value. The sign determination coefficient is determined to monotonously decrease from a positive maximum value to a negative minimum value.

  By using the above peak filter as a variable filter, the average value of the center frequency correction amount can be linearly changed over a wider range than the local frequency region. Therefore, a correction amount having a magnitude proportional to the deviation between the frequency to be suppressed and the current center frequency value can be obtained in a wide frequency range. Correction of the center frequency according to the degree of deviation can be executed, such that the correction is large if the deviation is large, and is small if the deviation is small. Therefore, the center frequency of the notch filter can be quickly converged and matched with the frequency to be suppressed (for example, the resonance frequency to be controlled).

  Further, since the frequency amplitude characteristic of the variable filter has a peak at the current value of the center frequency, the center frequency can be kept in the vicinity of the resonance frequency that first coincides in the search process of the center frequency. In this way, when importance is attached to enhancing the effect of keeping the center frequency close to the resonance frequency, it is preferable to make the peak width smaller than the local frequency region. On the other hand, when it is important to reduce the calculation time required for searching for the resonance frequency (that is, the number of times of updating the center frequency), it is preferable to increase the peak width.

  In one embodiment, the sign determination coefficient is represented by the cosine of the phase shift of the output signal from the variable filter. The first and second phase shifts are set to have opposite phases. One of the first and second phase shifts is set to a phase lag selected from a range of 0 degree or more and less than 90 degrees, and the other of the first and second phase shifts is set from 90 degrees or more and 180 degrees or less. It may be set to the selected phase delay. Preferably, one of the first and second phase shifts is a 0 degree phase lag and the other is a 180 degree phase lag. Alternatively, one of the first and second phase shifts may be a phase lag selected from a range of 0 degrees to 60 degrees, and the other may be a phase lag selected from a range of 120 degrees to 180 degrees. At this time, the third phase shift may be a phase delay of 90 degrees.

  In one embodiment, the correction calculation unit corrects the center frequency correction amount by using a correction coefficient generated from at least one of the input signal and the output signal of the variable filter, thereby adjusting the amplitude of the input signal to the variable filter. The influence on the center frequency correction amount may be reduced.

  For example, the correction calculation unit may calculate the product of the input signal and output signal of the variable filter and the correction coefficient as the corrected center frequency correction amount. At this time, the correction coefficient may be defined to be inversely proportional to any one of the square of the input signal of the variable filter, the square of the output signal, and the absolute value of the product of the input signal and the output signal. When the product of the sign of the input signal of the variable filter and the output signal is used as the center frequency correction amount, the correction coefficient may be defined to be in inverse proportion to the absolute value of the output signal or the input signal, for example.

  In this way, by determining the center frequency correction amount and the correction coefficient so that the orders of the amplitude of the input signal are equal to each other, the amplitude of the input signal is canceled in the corrected center frequency correction amount. Therefore, the influence of the amplitude of the input signal can be eliminated. In this case, coupled with the use of the above-described peak filter as a variable filter, the average value of the center frequency correction amount can be linearly changed over a wide frequency range, for example, from near zero to near the Nyquist frequency.

  In one embodiment, a resonance suppression device that suppresses resonance that occurs in a controlled object using a notch filter is provided. This apparatus includes vibration component extraction means, a phase difference filter, and coefficient correction means. The vibration component extraction unit extracts the vibration frequency component of the control target from either the output signal of the control target or the input signal for the control target. The phase difference filter can change the filter coefficient. The coefficient correction means corrects the coefficients of the notch filter and the phase difference filter according to the product pu of the output u of the vibration component extraction means and the output p obtained by passing the output u through the phase difference filter. The phase difference filter is an in-phase signal in the frequency region lower than the current center frequency and opposite in the frequency region higher than the current center frequency, or opposite in phase in the frequency region lower than the current center frequency and in phase in the higher frequency region, The frequency phase characteristic may be In this way, an adaptive notch filter that automatically adjusts the center frequency of the notch filter to match the natural frequency of the controlled object can be realized with a relatively small amount of computation.

  Further, the coefficient correcting means may correct the coefficients of the notch filter and the phase difference filter according to a value obtained by dividing the product pu by the square of the output signal p. The square of the output signal p may be smoothed. Instead of the square of the signal p, a square of the square of the signal u or the square of the product pu may be used. In this way, the correction amount of the center frequency can be made independent of the amplitude of the input u to the phase difference filter.

  The phase difference filter has a phase lag of 90 degrees at the center frequency, a frequency phase characteristic in which the phase changes from 0 degree to 180 degrees in a certain bandwidth near the center frequency, and a maximum gain at the center frequency in the bandwidth. It may be a peak filter having a frequency amplitude characteristic having a peak that takes a value, and capable of adjusting the bandwidth.

In this way, a large value the center frequency correction amount [Delta] [omega ₀ as the center frequency omega ₀ of the notch filter and the natural frequency omega _n of the control target are separated, and the natural frequency omega _n center frequency omega ₀ The closer the value is, the smaller the correction amount Δω ₀ can be made. In addition, when the input u to the phase difference filter includes a plurality of frequency components, the center frequency ω ₀ can be kept at the first matching frequency among the plurality of frequencies included in the input u.

FIG. 1 is a block diagram showing a configuration of an adaptive notch filter 10 according to an embodiment of the present invention. The adaptive notch filter 10 includes a notch filter 12 and a filter coefficient adjustment unit 13. The notch filter 12 is a known filter having a frequency characteristic shown in FIG. 2, for example. Notch filter 12, at the center frequency omega ₀ has a minimum value of the amplitude gain, and outputs to the output signal tau ₂ removes frequency components of the center frequency omega ₀ of the input signal tau _1. The notch filter 12 may be configured to remove a plurality of frequency components, and may include, for example, a plurality of notch filters connected in series.

The input signal τ ₁ to the notch filter 12 is, for example, a control command to a control target to which the notch filter 12 is applied. The input signal τ ₁ may be generated based on an error between a detection value of an output from the control target and a desired target command value. The input signal τ ₁ may be a target command. The input signal τ ₁ may be an observation amount (for example, position, speed, acceleration, etc.) from the control target. The output signal τ ₂ of the notch filter 12 may be used as a control input to the control target. The filter coefficient of the notch filter 12 is adjusted so as to remove the natural frequency component to be controlled from the input signal τ ₁ . For this purpose, the center frequency ω ₀ of the notch filter 12 is adjusted to coincide with any natural frequency component of the control target.

  The filter coefficient adjustment unit 13 corrects the filter coefficient of the notch filter 12 based on the reference signal r. The reference signal r may be a control command to a control target to which the notch filter 12 is applied, or may be an observation amount from the control target. The filter coefficient adjustment unit 13 may use a reference signal r generated from noise generated by the vibration of the control target. For this purpose, a reference signal generation unit that generates a reference signal r by analyzing the frequency component of the sound emitted by the control target may be provided. A sound collector such as a microphone may be provided for collecting the sound generated by the control target and supplying the collected sound to the reference signal generation unit. In this way, the filter coefficient adjustment unit 13 may use any signal that can extract the vibration component to be controlled as the reference signal r.

The filter coefficient adjustment unit 13 includes a vibration component extraction unit 14, a phase difference filter 16, and a correction calculation unit 18. The vibration component extraction unit 14 is provided to remove a frequency component unnecessary for correcting the notch center frequency ω ₀ from the reference signal r. The vibration component extraction unit 14 receives the reference signal r and outputs a signal u including a band including a frequency component to be removed by the notch filter 12. The signal u preferably contains only frequency components to be removed by the notch filter 12. That is, the vibration component extraction unit 14 extracts a frequency component to be removed by the notch filter 12 from the reference signal r.

Here, the frequency components unnecessary for the correction of the notch center frequency ω ₀ include frequency components in a frequency region lower than the center frequency ω ₀ . In general, in the reference signal r, a frequency component in a lower frequency range than the center frequency ω ₀ such as a DC component (in other words, a frequency component of 0 Hz) or a main frequency component of the target command has a large amplitude. Many. The center frequency correction method according to an embodiment attempts to make the center frequency coincide with a frequency component having a large amplitude in the vicinity of the current center frequency. For this reason, the center frequency ω ₀ tends to be corrected slightly lower than the natural frequency component to be controlled due to the influence of the low frequency component having a large amplitude in the reference signal r. Therefore, the vibration component extraction unit 14 is preferably configured as, for example, a high-pass filter whose pass band is a frequency region higher than the control frequency band.

Further, the vibration component extraction unit 14 may be configured to remove frequency components (for example, noise unrelated to resonance) included in a frequency region higher than the center frequency ω ₀ . In this case, the vibration component extraction unit 14 may be configured as a bandpass filter whose pass band is a frequency region including the center frequency ω ₀ and frequency components in the vicinity thereof.

The vibration component extraction unit 14 is a difference calculation unit that outputs a difference between a signal corresponding to a reference signal r generated based on a model representing input / output characteristics of a control target and a target input and an actual reference signal r. May be. In this case, the model that represents the input / output characteristics of the controlled object may be a model that describes a low-order natural vibration component (for example, only the first-order natural frequency component). Then, the output signal of the vibration component extraction unit 14 can be made to include only the high-order natural frequency component by removing the target input and the low-order natural frequency component from the input actual reference signal r. . According to the knowledge obtained by the present inventor, it is often possible to obtain a preferable control characteristic when the center frequency ω ₀ is made to coincide with a higher order natural frequency (for example, a second order natural frequency). By taking the difference between the signal generated based on the model and the actual reference signal r as described above, a signal in which frequency components other than the higher-order natural frequency components are suppressed can be easily obtained.

The vibration component extraction unit 14 may be configured to include at least one of the above-described high-pass filter, band-pass filter, and difference calculation unit. Conversely, the correction calculation unit 18 may correct the filter coefficient based on the reference signal r and the phase difference filter output of the reference signal r without providing the vibration component extraction unit 14. For example, if the amplitude of the unwanted frequency components in the correction of the center frequency omega ₀ is expected an error of less modification result is smaller, the reference signal r amplitude is suppressed in the unnecessary frequency components in the correction of the center frequency omega ₀ If obtained, the vibration component extraction unit 14 may be omitted.

The phase difference filter 16 receives the output signal u of the vibration component extraction unit 14 and outputs a phase difference filter output signal p. Here, the phase difference filter 16 refers to a filter that gives a phase shift according to a frequency component. The phase characteristic of the phase difference filter 16 is that the phase shift of the output signal p is changed from the first phase shift to the second as the frequency of the input signal u increases from the lower limit frequency to the upper limit frequency of the local frequency region including the center frequency ω ₀ . Change monotonically to phase shift. In the lower frequency region than the lower limit frequency, the phase shift is substantially equal to the first phase shift, and in the higher frequency region than the upper limit frequency, the phase shift is substantially equal to the second phase shift.

When the correction of the center frequency ω ₀ is performed using the center frequency correction amount Δω ₀ described in detail below, the phase characteristic of the phase difference filter 16 is substantially lower in the lower frequency region than the lower limit frequency of the local frequency region. It is preferable that a phase delay of 0 degree is given to (i.e., the phase is not substantially delayed), and a phase delay of 180 degrees is given in a frequency region higher than the upper limit frequency. The phase characteristics of the phase difference filter 16 are such that the phase delay of the output signal p increases from 0 degrees to 180 degrees as the frequency of the input signal u increases from the lower limit frequency to the upper limit frequency in the local frequency region. When the frequency component of the input signal u is equal to the center frequency ω ₀ , the phase delay of the output signal p is set to be equal to 90 degrees.

In a preferred embodiment, the phase difference filter 16 may be a peak filter having a frequency amplitude characteristic having a gain peak having a bandwidth in the local frequency region at the center frequency ω ₀ in addition to the above phase characteristic. This bandwidth (that is, peak width) is a frequency range in which the gain is attenuated from the peak by a predetermined amount (for example, 1 / √2). An example of the frequency amplitude characteristic and the frequency phase characteristic of the peak filter is shown in FIG. As shown in frequency-phase characteristic of FIG. 3, the phase contrast filter 16, the center frequency omega ₀ takes a reference phase delay (e.g. 90 degrees) at the center frequency omega ₀ sufficiently small phase lag than the reference phase delay in the neighborhood of It has a phase characteristic that changes from (for example, 0 degrees) to a sufficiently large phase delay (for example, 180 degrees).

In another embodiment, the phase difference filter 16 may be an all-pass filter having the above phase characteristics. The all-pass filter has a frequency amplitude characteristic with a gain value of 1 in the entire frequency region. The phase difference filter 16 may be a phase shifter or FIR filter that causes a phase delay in proportion to the difference between the frequency ω of the input signal u and the center frequency ω ₀ .

The correction calculation unit 18 corrects the filter coefficients of the notch filter 12 and the phase difference filter 16 based on the phase difference filter input signal u and the phase difference filter output signal p. That is, the correction calculation unit 18 updates the filter coefficient at the time point n of the notch filter 12 and the phase difference filter 16 to the filter coefficient at the time point n + 1 based on the input signal u and the output signal p. For example, the correction calculation unit 18 updates the center frequency ω ₀ to the value ω ₀ [n] at the time point n with the value ω ₀ [n + 1] at the time point n + 1 by the following equation. That is, the correction calculation unit 18 obtains the updated value ω ₀ [n + 1] by adding the correction amount Δω ₀ to the current value ω ₀ [n] of the center frequency ω ₀ .

The second term on the right side of Equation 1 is the correction amount Δω ₀ of the center frequency ω ₀ . Here, u [n] and p [n] denote the input signal u and the output signal p of the phase difference filter at time n, respectively. Φ _p [n] is a correction coefficient at time n. Although this correction coefficient will be described later, it is a correction coefficient for reducing the influence of the amplitude α of the input signal u. The correction coefficient Φ _p [n] is, for example, a smoothed square of the phase difference filter output signal p [n]. Since the output signal p [n] is a signal including a vibration component, it may take 0 or a value close to 0. Therefore, in order to avoid that the correction coefficient Φ _p [n] is 0 or a value close to 0 and the center frequency correction amount Δω ₀ is excessive, it is preferable to perform a smoothing process. The smoothing process may be performed by, for example, a low-pass filter. μ is a correction gain for adjusting the correction amount Δω.

  The correction coefficient may be obtained by smoothing the square of the phase difference filter input signal u. Alternatively, the correction coefficient may be the square root of the square of the product pu of the input signal u and the output signal p. In this case, the square root of the square of the product pu may or may not be smoothed. When the smoothing process is performed, the square root of the square of the product pu may be smoothed, or the square of the product pu may be smoothed to obtain the square root. Each of the square of the output signal p and the square of the input signal u May be the square root of the product of the smoothed signals, or the product of the smoothed absolute values of the output signal p and the input signal u.

The correction calculation unit 18 may increase the update frequency of the filter coefficient of the phase difference filter 16 more than the update frequency of the filter coefficient of the notch filter 12. For example, the correction calculation unit 18 may sequentially update the filter coefficient of the phase difference filter 16 at each control cycle, and may update the filter coefficient of the notch filter 12 at a low frequency (for example, every several control cycles). . Alternatively, the correction calculation unit 18 may correct the filter coefficient of the notch filter 12 after confirming that the center frequency ω ₀ matches the natural frequency to be controlled. In this case, the notch filter 12 may determine whether or not the center frequency ω ₀ matches the natural frequency of the controlled object by observing the control output from the controlled object.

Specific examples of the notch filter 12 and the phase difference filter 16 will be described. A specific example of the phase difference filter 16 is a peak filter. FIG. 2 is a diagram illustrating an example of frequency characteristics of the notch filter. FIG. 3 is a diagram illustrating an example of frequency characteristics of the peak filter. If the notch filter 12 and peak filter is a digital filter, the transfer function G _N and the transfer function G _P of the peak filter of the notch filter 12 is represented by the respective formulas 2 and Formula 3.

The filter coefficient of the notch filter 12 is expressed by Expression 4, and the filter coefficient of the peak filter is expressed by Expression 5. Here, ω ₀ is the center frequency of the notch filter 12. ζ ₁ and ζ ₂ are parameters for determining a gain peak and a notch width at the center frequency ω _0, respectively. Ts is a sampling time. ζ ₃ is a parameter for determining the peak width of the peak filter.

In the case of this specific example, the correction calculation unit 18 first obtains an update value ω ₀ [n + 1] of the center frequency using Equation 1, and updates each filter coefficient of Equation 4 and Equation 5 using this update value. It should be noted that the coefficient l _p expressed in Equation 5 may be fixed at the initial value and not updated, or may be updated at an update frequency lower than the update frequency of the center frequency. When the coefficient l _p is not updated, the peak width of the peak filter changes due to the change of the center frequency ω ₀ . By reducing (or not performing) the update frequency of the coefficient l _p , the calculation amount in the correction calculation unit 18 can be reduced.

Another example of the notch filter 12 and the peak filter will be described. Notch filter 12 and peak filter is a digital filter, and when the gain at the center frequency omega ₀ is -∞dB, the transfer function G _N and the transfer function G _P of the peak filter notch filter 12 and a respective formulas 6 It is represented by Formula 7. Equation 7 is the same as Equation 3. Each filter coefficient is expressed by Equation 8.

Also in this example, the correction calculation unit 18 first obtains an update value ω ₀ [n + 1] of the center frequency using Equation 1, and updates each filter coefficient of Equation 8 using this update value. Note that the coefficients l _N and l _p expressed in Expression 8 may be fixed at their initial values and not updated, or may be updated at an update frequency lower than the update frequency of the center frequency. Good. When the coefficients l _N and l _p are not updated, the notch width of the notch filter and the peak width of the peak filter change due to the change of the center frequency ω ₀ . By reducing (or not performing) the update frequency of the coefficients l _N and l _p , the calculation amount in the correction calculation unit 18 can be considerably reduced.

The coefficient l _N, in the case of sequential updating the same frequency as the center frequency omega ₀ a l _p, the coefficients l _N corresponding to the center frequency omega _{0 (or} coefficient _k), calculated in advance a table of l _p By preparing, the amount of calculation in the correction calculation unit 18 can be reduced. The correction calculation unit 18 can obtain the coefficients l _N and l _p corresponding to the updated value of the center frequency (or coefficient k) by referring to the table stored in the storage unit (not shown).

FIG. 4 is a diagram showing the relationship between the center frequency ω ₀ and the coefficient k. Here, the sampling time Ts is 4 ms. As shown, the coefficient k decreases monotonously as the center frequency ω ₀ increases. Therefore, instead of updating the center frequency ω ₀ using Equation 1, the correction calculation unit 18 may directly update the coefficient k using the following equation. Expression 9 is the same as Expression 1, but the correction gain is replaced with a correction gain μ _k for adjusting the coefficient k.

  Therefore, the correction calculation unit 18 directly corrects the coefficient k based on the phase difference filter input signal u and the phase difference filter output signal p. That is, the correction calculation unit 18 updates the coefficient k [n] at the time point n to the coefficient k [n + 1] at the time point n + 1 based on the input signal u and the output signal p.

Next, the principle of correcting the center frequency ω ₀ in one embodiment of the present invention will be described. For simplicity, it is assumed that the input signal u to the phase difference filter 16 is a sine wave having a single frequency component having an amplitude α and a frequency ω. At this time, the input signal u and the output signal p of the phase difference filter 16 are expressed by Expression 10. Here, the amplitude gain and the phase shift of the phase difference filter 16 are expressed as | _GP (jω) | and φ _p (ω), respectively.

In one embodiment, the center frequency correction amount Δω ₀ is determined to depend on the product pu of the input signal u and the output signal p of the phase difference filter 16. The average value E [pu] of the product pu is expressed by Equation 11.

As described above, the phase characteristic of the phase difference filter 16 indicates that the phase shift of the output signal p is first as the frequency of the input signal u increases from the lower limit frequency to the upper limit frequency in the local frequency region including the center frequency ω ₀ . The phase shift is monotonously changed from the phase shift to the second phase shift. At the center frequency ω ₀ , a reference phase shift is taken between the first phase shift and the second phase shift. In the example shown in FIG. 3, the phase contrast filter 16, the center frequency omega given reference phase delay (e.g. 90 degrees) at _0, the center frequency omega ₀ reference phase delay smaller phase lag than in the low frequency region near the And has a phase characteristic that gives a phase lag greater than the reference phase lag in the high frequency region near the center frequency ω ₀ .

Therefore, the center frequency omega ₀ in sign determining factor cos _{(φ p} (ω)) is zero, sign determining factor when the frequency omega is less than the center frequency omega ₀ of the input signal u is a positive value, the input signal u When the frequency ω is greater than the center frequency ω ₀ , the sign determination coefficient is a negative value. This can be summarized by Expression 12.

Therefore, it can be said that the average value E [pu] of the product pu has cos (φ _p (ω)) as a sign determination coefficient. The sign determination coefficient cos (φ _p (ω)) determines the sign of the average value of the center frequency correction amount Δω ₀ according to the phase shift φ _p (ω) of the output signal p of the phase difference filter 16. As can be seen from Equation 11, the portion of the average value E [pu] other than the sign determination coefficient cos (φ _p (ω)) is clearly a positive value, and the code constant portion where the code is constant regardless of the frequency component. It is. The average value E [pu] is represented by the product of the constant code portion and the code determination coefficient.

That is, the sign of the average value E [pu] of the product pu is determined by the magnitude relationship between the frequency ω of the input signal u to the phase difference filter 16 and the center frequency ω ₀ . If the frequency ω of the input signal u is smaller than the center frequency ω ₀ , the product pu has a positive value, and if the frequency ω of the input signal u is greater than the center frequency ω ₀ , the product pu has a negative value. Thus, as represented in Equation 13, by updating the center frequency omega ₀ using a recurrence formula whose center frequency correction amount a product pu, to the input frequency omega of the center frequency omega ₀ of the notch filter 12 It is possible to match.

When the input frequency ω is a natural frequency component to be controlled, the center frequency ω ₀ of the notch filter 12 can be matched with the natural frequency component. In this way, the center frequency ω ₀ of the notch filter 12 can be automatically adjusted to the natural frequency component to be controlled.

More preferably, the influence of the amplitude α of the input signal u can be reduced or eliminated by introducing a correction coefficient into the center frequency correction amount Δω ₀ . As can be seen from Equation 12, the product pu depends on the amplitude α of the input signal u. Formula 14 is a recurrence formula for updating the center frequency ω ₀ when the correction coefficient Φ [n] is introduced into the center frequency correction amount Δω ₀ .

Here, if the correction coefficient Φ [n] is rewritten as μ / Φ _p [n], Expression 14 corresponds to Expression 1. As an example, a case where Φ _p [n] is obtained by smoothing the square of the phase difference filter output signal p [n] as described above will be described. Smoothing is performed, for example, by processing the square of the output signal p [n] with a low-pass filter having a cutoff frequency ωcp. Then, the average value of Φ _p [n] is given by Equation 15.

Therefore, the average value E [Δω ₀ ] per correction operation of the center frequency correction amount corrected by the correction coefficient is given by Expression 16. As can be seen from Equation 16, the average value E [Δω ₀ ] is expressed in a format that does not depend on the amplitude α of the input signal u. Therefore, the influence of the amplitude α of the input signal u can be eliminated by introducing a correction coefficient into the center frequency correction amount Δω ₀ .

FIG. 5 is a diagram showing the principle of correcting the center frequency ω _{0 according} to one embodiment of the present invention as frequency characteristics. FIG. 5 is a Bode diagram created for the average value E [Δω ₀ ] shown in Equation 16 with a gain of 1 / | _GP (jω) | and a phase of φ _p (ω). The Bode diagram shown in FIG. 5 is an example when the phase difference filter 16 is a peak filter shown in FIG. The coefficient μ is set to μ = 1 for simplicity. As shown in FIG. 5, with respect to the amplitude characteristics, notches corresponding to the gain peaks of the peak filter appear. As for the phase characteristics, the phase characteristics corresponding to the phase characteristics of the peak filter are also shown.

FIG. 6 is a diagram illustrating an average value E [Δω ₀ ] of the center frequency correction amount when a peak filter is used as the phase difference filter 16. The average value E [Δω ₀ ] shown in FIG. 6 is the corrected correction amount shown in Expression 16. As shown in FIG. 6, the correction amount average value E [Δω ₀ ] is not only in the vicinity of the center frequency ω ₀ but also in a wide range of frequencies ranging from near zero to the vicinity of the Nyquist frequency ω _nyq (1/2 of the sampling frequency). In the region, it can be seen that there is a linear change with respect to the deviation between the center frequency ω ₀ and the input frequency ω. That is, in the band below the Nyquist frequency ω _nyq, the average value E [Δω ₀ ] of the center frequency correction amount is substantially proportional to the deviation between the center frequency ω ₀ and the input frequency ω.

Therefore, the correction amount Δω ₀ corresponding to the deviation between the center frequency ω ₀ and the input frequency ω can be obtained. That is, the correction amount Δω ₀ at the time of update increases as the notch center frequency ω ₀ is separated from the frequency ω to be suppressed by the adaptive notch filter 10. Therefore, the center frequency ω ₀ can be brought close to the frequency ω of the input signal u with a small number of update processing iterations. Further, the correction amount Δω ₀ decreases as the center frequency ω ₀ approaches the frequency ω to be suppressed. Therefore, it is possible to prevent the center frequency omega ₀ varies vibrationally every update the center frequency omega ₀ in the vicinity of the frequency omega of the input signal u. The center frequency ω ₀ can be quickly matched with the frequency ω of the input signal u.

In addition, since the phase difference filter 16 is a peak filter, the center frequency ω ₀ can be kept at the frequency ω after the center frequency ω ₀ is once matched with the frequency ω of the input signal u. . Since the phase difference filter 16 is a peak filter, the amplitude is greatly amplified at the center frequency ω ₀ . Therefore, even if another frequency component deviating from the center frequency ω ₀ is included in the input signal u, the center frequency ω ₀ is shifted from the frequency ω of the input signal u that already matches toward the other frequency. It becomes difficult to move away. Therefore, from the initial value of the center frequency ω _{0 to} the frequency ω of the input signal u, it can be performed quickly with a relatively large correction amount, and once the frequency is matched, the center frequency ω ₀ is bound to the frequency ω. can do. Further, the frequency ω may change gradually due to some factor such as a change with time. When such a drift occurs, the center frequency ω ₀ can be followed.

For example, when the frequency amplitude characteristic of the input signal u includes a plurality of frequency components having a peak, the initial value of the center frequency is set to a value close to the frequency component to be matched with other frequency components. Update the center frequency. In this way, the center frequency ω ₀ can be made to coincide with the desired frequency and remain at that frequency unless the amplitude of the other frequency is very large compared to the amplitude of the frequency to be matched.

According to the knowledge obtained by the present inventor, in the control system shown in FIG. 8, it is often possible to obtain preferable control characteristics by matching the center frequency ω ₀ to a higher-order natural frequency not included in the model. . For this reason, it is preferable to update the center frequency by setting the initial value of the center frequency as high as possible. In the input signal u of the phase difference filter 16, a component having an amplitude larger than a high-order natural frequency such as a low-frequency component or a first-order natural frequency component due to a control input often exists in a low band. Because.

FIG. 7 is a diagram showing an average value E [Δω ₀ ] of the center frequency correction amount when an all-pass filter is used as the phase difference filter 16. This all-pass filter has the same phase characteristics as the peak filter illustrated in FIG. 3, and the frequency amplitude characteristic has a gain of 1 at all frequencies. Therefore, by setting | _GP (jω) | to 1 in Equation 16, the correction amount average value E [Δω ₀ ] of the all-pass filter can be obtained.

As shown in FIG. 7, the correction amount average value E [Δω ₀ ] is switched from the negative minimum value to the positive maximum value in the vicinity of the center frequency ω ₀ . The correction amount average value E [Δω ₀ ] is substantially constant at a negative minimum value in a frequency region lower than the switching range in the vicinity of the center frequency ω ₀ , and in a frequency region higher than the switching range in the vicinity of the center frequency ω ₀ . Is the maximum positive value and almost constant. For this reason, if the difference between the center frequency ω ₀ and the frequency ω of the input signal u is large to some extent, the amount of the center frequency correction amount Δω ₀ is substantially constant. Therefore, it is considered that the time change of the center frequency ω ₀ tends to be oscillating. Therefore, when it is important to avoid the vibrational time change of the center frequency ω ₀ , it is preferable to employ a peak filter for the phase difference filter 16. In the case where the adaptive notch filter 10 is applied to a control target that can allow a vibrational change in the center frequency ω ₀ , an all-pass filter may be employed for the phase difference filter 16.

In one embodiment, the phase difference filter 16 may be a phase shifter or FIR filter that causes a phase delay in proportion to the difference between the frequency ω of the input signal u and the center frequency ω ₀ . In this case, when the center frequency ω ₀ is near ½ of the Nyquist frequency, the correction amount average value E [Δω ₀ ] is the same as that when the peak filter is used. However, when the center frequency ω ₀ is ¼ or less of the Nyquist frequency, the corrected average value E [Δω ₀ ] is greater than the deviation between the center frequency ω ₀ and the input frequency ω in the region of ¾ or more of the Nyquist frequency. When the center frequency ω ₀ is 3/4 or more of the Nyquist frequency, the corrected average value E [Δω ₀ ] is equal to the center frequency ω ₀ and the input frequency in the region of ¼ or less of the Nyquist frequency. It does not change linearly with respect to the deviation from ω.

In the above embodiment, the center frequency correction amount Δω ₀ that depends on the product pu of the input signal u and the output signal p of the phase difference filter 16 is used, but the present invention is not limited to this. For example, a center frequency correction amount Δω ₀ that depends on the product of the sign of the input signal u and the output signal p may be used. In this case, it is preferable to use, for example, a smoothed absolute value of the output signal p as the correction coefficient Φ _p [n].

FIG. 8 is a block diagram showing a system configuration of a resonance suppression device according to an embodiment of the present invention. The electric motor 20 drives the load 22. The electric motor 20 is, for example, an electric motor incorporated in a device in which control characteristics may be limited due to resonance of an industrial robot, an injection molding machine, a construction machine, a precision positioning stage, or the like. The detector 24 measures the output of the electric motor 20. The detector 24 is, for example, a speed detector that measures the detection speed ω ^* of the electric motor 20.

A speed command generator (not shown) of the resonance suppression device determines a speed command ω _dir . The speed control unit 26 generates a torque command signal to the motor 20 based on an error of the detected speed ω ^* with respect to the speed command ω _dir to the motor 20. The speed control unit 26 outputs a torque command τ ₁ so that the difference between the speed command ω _dir and the detected speed ω ^* of the electric motor 20 is zero and the detected speed ω ^* follows the speed command value ω _dir . For example, the speed control unit 26 outputs the result of proportional integration of the difference ω _dir −ω ^* between the speed command ω _dir and the detected speed ω ^* of the electric motor 20 as the torque command τ ₁ .

The notch filter 12 removes the frequency component of the center frequency ω ₀ from the torque command τ ₁ and outputs a new torque command τ ₂ . Since the center frequency ω ₀ matches the frequency component of the natural frequency ω _n of the system including the electric motor 20 and the load 22, the notch filter 12 torques the new torque command τ _{2 from} which the natural frequency component has been removed. The data is output to the control unit 28. The torque control unit 28 controls the electric motor 20 based on the output signal of the notch filter 12. The torque control unit 28 controls the supply current to the electric motor 20 so that the electric motor 20 outputs the torque τ ^* that matches the torque command τ ₂ . In this way, speed control of the electric motor 20 is performed.

As described with reference to FIG. 1, the filter coefficient adjustment unit 13 includes a vibration component extraction unit 14, a phase difference filter 16, and a correction calculation unit 18. The filter coefficient adjustment unit 13 uses the detection speed ω ^* as the reference signal r. The filter coefficient adjustment unit 13 corrects the coefficients of the notch filter 12 and the phase difference filter 16 so that the center frequency ω ₀ of the notch filter 12 matches the vibration frequency included in the speed ω ^* .

If the natural frequency ω _n of the system is included in the torque τ ^* output by the electric motor 20, the natural vibration of the system is excited by the driving of the electric motor and resonance occurs. The notch filter 12 is inserted between the speed control unit 26 and the torque control unit 28, the component of the natural frequency ω _n is removed from the output τ ₁ of the speed control unit 26, and the input torque command τ to the torque control unit 28 is removed. Resonance can be suppressed by generating ₂ . If the center frequency ω ₀ of the notch filter 12 deviates from the natural frequency ω _{n of the} system, resonance occurs and a component of the natural frequency ω _n of the system is included in the detection signal ω ^* . In this case, since the filter coefficient adjustment unit 13 of the adaptive notch filter 10 uses the detection signal ω ^* as the reference signal r, the center frequency ω ₀ can be automatically adjusted to coincide with ω _n .

  FIG. 9 is a diagram illustrating an example of a response of the control system illustrated in FIG. Before the time 0, the function of the adaptive notch filter 10 is stopped, and the electric motor 20 is driven at a constant rotational speed of 1000 rpm. When the adaptive notch filter 10 is disabled (period A in the figure), the speed response waveform is oscillatory.

The operation of the adaptive notch filter 10 is started at time 0. The initial value of the notch center frequency ω ₀ of the adaptive notch filter 10 is set to 1200 Hz. Simultaneously with the effective switching of the adaptive notch filter 10, a stepped speed command was applied to the motor 20. As a result, the center frequency ω ₀ was corrected by the adaptive notch filter 10, and the center frequency ω ₀ was able to converge to 314 Hz in about 0.08 seconds (period B in the figure). The center frequency of 314 Hz obtained in this way substantially matches the natural frequency of the system confirmed by another method. Therefore, the vibration of the speed response is suppressed after 0.08 seconds when the notch center frequency ω ₀ converges to the natural frequency of 314 Hz.

  In this embodiment, the notch filter 12 is provided between the speed control unit 26 and the torque control unit 28, and the torque command from the speed control unit 26 is described as an input to the notch filter 12. However, in other embodiments, a speed command, a detected speed, or an error signal may be used as an input to the notch filter. That is, the notch filter may receive an input signal to the speed control unit, a signal for generating the input signal, or a torque command signal from the speed control unit. For example, in the configuration shown in FIG. 8, the notch filter 12 may be provided after the detector 24, that is, between the detector 24 and the speed control unit 26. Alternatively, the notch filter 12 may be provided after the speed command generation unit, that is, before the speed control unit 26. Even in this case, vibration can be similarly suppressed.

  As described above, according to an embodiment of the present invention, the center frequency of the adaptive notch filter 10 is automatically adjusted without applying a signal dedicated to correction, such as a swept sine wave signal, from the outside to the control system. be able to. The correction calculation unit 18 of the adaptive notch filter 10 can determine the correction amount of the center frequency based on the input signal and output signal of the phase difference filter 16. For this reason, the amount of calculation required for coefficient correction can be reduced. Further, by using a peak filter for the phase difference filter 16, a center frequency correction amount proportional to the deviation between the center frequency and the vibration frequency of the system can be obtained, so that the center frequency can be quickly adjusted with a small number of update processes. Can match the vibration frequency.

  DESCRIPTION OF SYMBOLS 10 Adaptive notch filter, 12 Notch filter, 13 Filter coefficient adjustment part, 14 Vibration component extraction part, 16 Phase difference filter, 18 Correction calculation part, 20 Electric motor, 22 Load, 24 Detector, 26 Speed control part, 28 Torque control part .

Claims (9)

A resonance suppression device that suppresses resonance that may occur in a controlled object including an electric motor,
A speed control unit that generates a torque command signal to the motor based on an error in a detected speed with respect to a speed command to the motor;
An adaptive notch filter that outputs an input signal to the speed control unit, a signal for generating the input signal, and an output of the torque command signal as an input, and
The adaptive notch filter is
A center frequency can be changed, and a notch filter for suppressing a natural frequency component of the control target included in the output signal;
A variable filter having phase characteristics corresponding to the magnitude relationship between the frequency of an input signal to the variable filter and the current value of the center frequency, and using a signal derived from the control output of the control target as an input signal to the variable filter When,
The center frequency correction amount defined using the input signal and output signal of the variable filter is calculated so that the sign of the average value of the center frequency correction amount is determined according to the magnitude relationship, and the center frequency correction amount is calculated as the center frequency correction amount. And a correction operation unit that updates the center frequency based on the resonance suppression device . The variable filter has a phase characteristic that monotonously changes from a first phase shift to a second phase shift in a local frequency region including the current value, and an amplitude characteristic having a peak in the current value,
The average value of the center frequency correction amount is represented by a product of a code determination coefficient that determines a code according to a phase shift of an output signal from the variable filter, and a code invariant portion where the code is constant,
The resonance suppression apparatus according to claim 1, wherein the sign determination coefficient takes a positive value in one of the first and second phase shifts and takes a negative value in the other. The resonance suppression apparatus according to claim 1, wherein the center frequency correction amount depends on a product of an input signal and an output signal of the variable filter. The correction calculation unit corrects the center frequency correction amount by a correction coefficient generated from at least one of the input signal and the output signal of the variable filter, thereby correcting the center frequency of the amplitude of the input signal to the variable filter. 4. The resonance suppression device according to claim 1, wherein an influence on the amount is reduced. The correction calculation unit calculates a corrected correction amount depending on a product of the center frequency correction amount and the correction coefficient, and updates the center frequency based on the corrected correction amount.
5. The resonance according to claim 4, wherein the correction coefficient is inversely proportional to any one of a square of an input signal of the variable filter, a square of an output signal, and an absolute value of a product of the input signal and the output signal. Suppression device . The resonance suppression device according to claim 1, further comprising an extraction unit that extracts a band including the natural frequency component and generates an input signal to the variable filter. A resonance suppression method for suppressing resonance that can occur in a controlled object including an electric motor,
Generating a torque command signal to the motor based on a detected speed error with respect to the speed command to the motor by a speed control unit;
Outputting an output signal from the adaptive notch filter with any one of an input signal to the speed control unit, a signal for generating the input signal, and the torque command signal as an input to the adaptive notch filter;
Updating the center frequency of the notch filter for suppressing the natural frequency component of the control target included in the output signal ,
The adaptive notch filter includes the notch filter and a variable filter different from the notch filter,
The updating is
By the variable filter having a corresponding phase characteristic magnitude relation between the current value of the frequency and the center frequency of the input signal to the variable filter, the filter for an input signal to the variable filter derived from the control output of the control object and to the processing,
In that it comprises, and computing the center frequency correction amount that has been defined using the input signal and the output signal of the variable filter as the sign of the average value of the center frequency correction amount is determined in accordance with the magnitude relationship Feature method. A resonance suppression device that suppresses resonance that may occur in a controlled object including an electric motor,
A speed control unit that generates a torque command signal to the motor based on an error in a detected speed with respect to a speed command to the motor;
An adaptive notch filter that outputs an input signal to the speed control unit, a signal for generating the input signal, and an output of the torque command signal as an input, and
The adaptive notch filter is
A notch filter whose center frequency can be changed;
A variable filter having a phase characteristic monotonously changing in a local frequency region including a current value of the center frequency, and an amplitude characteristic having a peak in the current value;
A center frequency correction amount depending on an output signal obtained by processing the input signal including the frequency component to be suppressed by the notch filter by the variable filter, and an average value linearly changes in a wide band including the local frequency region. resonance suppression apparatus, characterized in that it comprises calculating the center frequency correction amount, and the modification calculator for updating the center frequency based on said center frequency correction amount, the for. A resonance suppression method for suppressing resonance that can occur in a controlled object including an electric motor,
Generating a torque command signal to the motor based on a detected speed error with respect to the speed command to the motor by a speed control unit;
Outputting an output signal from the adaptive notch filter with any one of an input signal to the speed control unit, a signal for generating the input signal, and the torque command signal as an input to the adaptive notch filter;
And a updating the center frequency of the adaptive notch filter,
The adaptive notch filter includes a notch filter that outputs the output signal, and a variable filter different from the notch filter,
The updating is
By the variable filter having a phase characteristic that varies monotonically at a local frequency region including the current value of the center frequency, and an amplitude characteristic having a peak to said current value, including a frequency component to be suppressed by the adaptive notch filter the method comprising filtering the input signal,
Wherein the including, and said depending on the output signal of the variable filter, and the average value in a broadband including the local frequency region for calculating the center frequency correction amount that varies linearly.

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