JP3470430B2 - Active vibration control device and active vibration control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active type vibration isolation technique for actively suppressing vibration in a vibration isolation target by applying a vibration force to the vibration isolation target. The present invention relates to an active vibration control device and an active vibration control method for adaptively controlling a vibration means that exerts a vibration force.

[0002]

2. Description of the Related Art Recently, as one means for achieving high demands for anti-vibration performance, Japanese Patent Application Laid-Open No. 64-83742.
As disclosed in Japanese Laid-Open Patent Publication No. 3-219140 and Japanese Patent Laid-Open Publication No. 3-219140,
There has been proposed an active vibration damping device that cancels out the vibration of a vibration damping target, and its application to, for example, an engine mount of an automobile is under study.

By the way, in such an active vibration isolator, as described in the above publication, in general,
An adaptive digital filter is used to control the vibrating means that exerts a vibrating force on the object to be isolated, and according to an algorithm such as the LMS method or the steepest descent method that minimizes the square error,
Adaptive detection is performed by using the detection signal of the residual vibration in the image stabilization target as an error signal and adjusting the filter coefficient so that the error signal becomes as small as possible. And
In such an adaptive control method that follows an algorithm that minimizes the squared error, in general, the filter coefficient sequentially converges toward the optimum value that normally exists to minimize the error signal, and The vibrating means is adaptively controlled so as to minimize the residual vibration in the body.

However, in such adaptive control, effective adaptive control cannot always be performed, and a divergent state may result. The causes are roughly classified into (1) the case where the magnitude (strength) of the exciting force exerted by the exciting means is not sufficient to cancel the vibration in the vibration-proof object, and (2) the filter coefficient There are two cases, a case where the simulated transfer characteristic (estimated value) of the vibration transfer system used when generating the reference signal necessary for updating is greatly different from the actual system. In this case, it is possible to suppress the divergence by coping with another method such as output feedback. However,
In the latter case, if the difference between the simulated transfer characteristic of the vibration transfer system and the actual system is out of the allowable range, the adaptive control updates the filter coefficient of the adaptive filter in the direction of gradually increasing the squared error. It was extremely difficult to deal with in order to go. And, in particular, it is not realistic because the vibration transmission system is complicated and it is difficult to accurately obtain the transmission characteristics as in an automobile, and it takes a lot of time and effort to make an accurate measurement. If the transfer characteristics of the vibration transfer system change due to running conditions or changes over time, it is highly possible that the simulated transfer characteristics will deviate from the actual system. There is a risk that the anti-vibration characteristics may be deteriorated, instead of being obtained.

[0005]

The present invention has been made in view of the circumstances as described above, and the problem to be solved is to diverge due to a large error in a simulated transfer characteristic of a vibration transfer system. It is an object of the present invention to provide an active vibration control device and an active vibration control method that can effectively prevent the above and stably obtain a desired anti-vibration effect.

[0006]

In order to solve such a problem, a feature of the present invention resides in that a vibration force is applied to a vibration isolation target object based on an input signal having a frequency component corresponding to a vibration to be isolated. An adaptive digital filter for controlling the vibrating means exerting an effect is provided, and an active digital filter for adaptively controlling the vibrating means is updated by updating the filter coefficient of the adaptive digital filter in a direction to reduce the residual vibration in the vibration isolation target. Type vibration control device, the frequency of the input signal is halved.
Frequency dividing means for generating a divided signal by frequency division, sampling means for obtaining a sample value sequence having a sampling period twice the basic sampling period from the divided signal, and the sample value sequence for the adaptive digital Sample value input means for inputting to the filter at a basic sampling cycle and frequency multiplying means for generating a control signal of the vibrating means by obtaining a square value of the output signal of the adaptive digital filter are provided. It is in the active vibration control device.

Further, in the first preferred aspect of the present invention, the sampling values sampled at the basic sampling period from the frequency-divided signal are sequentially distributed so that each sampling period has twice the basic sampling period. The sampling means is configured to include a duplication processing means for shaping two sample value sequences having different phases, and the sample value inputting means converts the two sample value sequences generated by the duplication processing means. , Are input alternately to the adaptive digital filter at a basic sampling period.

Further, according to the present invention, the vibrating means for exerting a vibrating force on the object to be vibrated is controlled by an adaptive digital filter which controls the vibrating means based on an input signal having a frequency component corresponding to the vibration to be vibrated. When adaptively controlling by updating the filter coefficient of the adaptive digital filter in a direction to reduce the residual vibration in the image stabilization target, the frequency of the input signal is divided into ½ to generate a divided signal, and A sample value sequence having a sampling period twice the basic sampling period is obtained from the divided signal, and the sample value sequence is input to the adaptive digital filter at the basic sampling period, while being obtained by the appropriate type digital filter. The present invention is also characterized by an active vibration control method in which the squared value of the output signal obtained is used as a control signal for the vibrating means.

[0009]

EXAMPLES Examples of the present invention will now be described in detail with reference to the drawings in order to clarify the present invention more specifically.

First, FIG. 1 shows a concrete example of the configuration in which the present invention is applied to a vibration isolation system (active vibration isolation device) of an automobile using a power unit system as a vibration source. It should be noted that FIG. 1 is a schematic diagram showing only the main configuration of the control system, omitting the A / D and D / A converters, the low-pass filter and the like. As shown in this figure, the vibration isolation system of this embodiment includes a plurality of engine mounts 1 for supporting the power unit 14 with respect to the body 12 of the automobile 10 with vibration isolation.
6 with one of them engine mount 1
As 6a, an active type engine mount provided with a vibrating means is adopted. The vibrating means of the engine mount 16a is controlled by the digital filter 18, and the filter coefficient of the digital filter 18 is updated by the adaptive filter 20 according to an adaptive algorithm, so that the engine mount 16a is vibrated. The vibrating means is adaptively controlled so that the vibrations transmitted from the power unit 14 to the driver's seat floor portion of the body 12 can be destructively suppressed.

As the engine mount 16a,
Various well-known mount devices equipped with a vibrating means utilizing electromagnetic force, magnetic force, piezoelectric power, magnetostrictive force, etc. can be adopted. Particularly, a device that can adjust the generated vibrating force by an electric signal is a point of controllability. From desirable. Further, when a large rigidity (load resistance) is required for supporting the power unit 14, an elastic supporting force by a rubber elastic body, spring means or the like can be exerted in addition to the exciting force by the vibrating means. In addition, it is also possible to employ a fluid-filled mount device in which a fluid chamber is formed inside and a vibration damping effect based on a fluid flow action is exhibited.

More specifically, the control device of this embodiment uses a signal corresponding to the engine vibration as the vibration source (for example, the vibration of the power unit 14 or the rotation angle of the engine crankshaft,
Alternatively, a sensor (not shown) for detecting an ignition signal or the like is provided, and based on the detection signal of this sensor, an input signal having a frequency component of vibration for the purpose of vibration isolation is obtained. . Incidentally, such an input signal can be obtained in the form of a sine wave, a rectangular wave, a pulse waveform, etc., depending on the detection target, the type of sensor used, etc.
In order to facilitate the subsequent signal processing, the input signal having a frequency component (FHz) corresponding to the vibration to be isolated is preferably obtained by modifying the sine waveform.

Then, the input signal is input to the frequency dividing device, and the frequency thereof is divided into ½, so that the frequency component (F /
2 Hz) is generated. The frequency division means dropping the frequency to a low frequency, and has the opposite meaning to the frequency multiplication to raise the frequency to a high frequency.

Specifically, the input signal and the frequency-divided signal are obtained, for example, by the following signal processing. That is, first, the frequency of the detection signal is calculated to generate a sine signal of a vibration frequency: F (Hz) for the purpose of image stabilization, and a minute lead angle for each sampling in the harmonic waveform and the divided waveform: δ, δ ′ Is obtained according to the following (Equation 1) and (Equation 2), respectively. δ _(rad) = 2π × F / Fs (Equation 1) δ ′ _(rad) = 2π × (F / 2) / Fs (Equation 2) (where Fs is the basic sampling frequency) Further, by calculating the following (Equation 3) and (Equation 4), it is possible to generate the input signal and the divided signal, respectively. B = B + δ, A sinB (Equation 3) B ′ = B ′ + δ ′, A ′ sinB ′ (Equation 4) (where A and A ′ are amplitudes and B and B ′ are phases)

The frequency-divided signal thus obtained is subjected to analog-digital conversion and is sampled at the basic sampling period to be converted into a pulse train to be a discretized signal. Then, by a multiplexing processing device (not shown), each sampling value forming such a pulse train is sequentially distributed,
Two sample value strings (a) and (b) are generated. That is, the sample value sequence (a) thus obtained,
(B) has a sampling period that is twice the basic sampling period, and has phases that differ from each other by an amount corresponding to the basic sampling period.

Then, the two sample value strings (a) and (b) thus duplicated are alternately input to the digital filter 18 at the basic sampling period by an input switching device (not shown). As a result, the digital filter 18 processes the input sample value sequences (a) and (b) in accordance with the preset filter coefficient to obtain the output signal.

Here, each sample value sequence (a),
Since each of (b) is composed of a pulse train obtained by sampling from the divided signal obtained by dividing the input signal by 1/2, each sample value sequence ( The frequency components in a) and (b) are both halved with respect to the input signal.

In each of the pulse trains forming the sample value trains (a) and (b), the divided signal obtained by dividing the input signal by ½ is used as the basic sampling period of 2 Since it is obtained by sampling at a double sampling period, the arrangement of signals in each of the sample value sequences (a) and (b) itself corresponds to the basic sampling frequency.
In addition, in the present embodiment, the two sample value sequences (a) and (b) are alternately input to the digital filter 18 at the basic sampling period. Therefore, the input period of the sample value sequence itself is It will be matched with the basic sampling period. Therefore, the output signal obtained by inputting the sample value sequences (a) and (b) having the frequency component divided by half to the input signal to the digital filter 18 is also intended for image stabilization. Although it corresponds to half the vibration frequency, the digital filter 18 designed at the basic sampling frequency can be effectively operated.

Further, the output signal of the digital filter 18 thus obtained is subjected to frequency multiplication processing to obtain the square value of the output signal and output as a control signal. The control signal may be substantially the square value of the output signal, and its specific processing method is not limited. For example, in addition to directly calculating the square value of the output signal, the square value can be calculated by a fine integration process, or the output signal can be calculated by using a separate electric frequency doubler. It is also possible to obtain a control signal by converting to a squared value. That is, as the frequency multiplication device, any calculation processing device or electric device that can obtain a signal that is substantially the square value of the output signal can be adopted.

That is, the control signal thus obtained as the square value of the output signal has a frequency of 2 with respect to the output signal.
It is doubled in frequency and therefore has a frequency component corresponding to the frequency: F (Hz) for the purpose of image stabilization. Therefore, such a control signal is input to the engine mount 16a via the A / C power amplifier 24,
By controlling the vibrating means, a vibrating force corresponding to the vibration frequency for the purpose of anti-vibration is generated.

When, for example, a square calculation is used as the frequency-division processing for obtaining the square value of the output signal, a DC component is added to the obtained control signal. If a vibrating means having a structure for obtaining a vibrating force is produced, there is a risk of malfunction. Therefore, the control signal obtained by the frequency multiplication process is subjected to a DC component removal process by using an A / C power amplifier or a high-pass filter, if necessary.

On the other hand, an error sensor 26 is mounted on the driver's floor, which is the vibration-proof target portion of the body 12.
By detecting the vibration of the floor portion by the error sensor 26, the vibration remaining on the driver's floor can be detected when the vibration force exerted by the engine mount 16a is applied to cancel the vibration. There is. The detection signal of the error sensor 26 is sent to the amplifier 28.
Is input to the comparator 30 via the
The difference from the target value (d = 0) obtained in (3) is input to the adaptive filter 20 as an error signal.

Further, in the adaptive filter 20, a reference signal (in this embodiment, the same as the input signal) having a frequency component of vibration for the purpose of image stabilization, which is obtained on the basis of the detection signal, is analog- After being digitally converted into a discretized signal, it is convolved with the simulated transfer characteristic: G _E and input. The simulated transmission characteristic: G _E is the engine mount 1
6a vibrating means, body 12, error sensor 26, A /
Transfer function as a transfer characteristic of various elements constituting a vibration and signal transfer system in a vibration isolation system such as a D converter: G
Is an estimated value of, and is obtained by actual measurement, calculation, or the like.

As a result, in the adaptive filter 20, the optimum solution of the filter coefficient that makes the error signal zero is successively calculated in accordance with the adaptive algorithm such as the LMS method or the steepest descent method, and this is used as the filter coefficient of the digital filter 18. By copying, the filter coefficient of the digital filter 18 can be changed at high speed, and the engine mount 1
The vibrating means 6a is adapted to be adaptively controlled. As is apparent from this, in this embodiment, the digital filter 18 and the adaptive filter 20 constitute an adaptive digital filter.

Here, by the adaptive filter 20,
When obtaining the optimum solution of the filter coefficient in the digital filter 18 according to the adaptive algorithm, in the vibration isolation system as described above, since the frequency-doubling processing process is incorporated in the control path, there are two optimum solutions. .

That is, when two output signals A and B having opposite phases (phase difference of 180 degrees) are considered as the output signals of the digital filter 18, the control signal obtained by performing the frequency multiplication processing is Even if any of the output signals: A and B is adopted, they have the same phase. Therefore, considering from the opposite, the control signal obtained through the frequency multiplication processing is two types of signals whose phases are inverted: A and B. Can be obtained from any of the above. Therefore, for example, the adaptive filter 20
Considering the adaptation process of the least squares method in which the number of taps of 2 is 2, the optimum condition of the adaptive filter 20 is unique as shown in FIG. , Simulated transfer characteristic: G _E actual transfer characteristic: if the difference with respect to G is within a permissible range, the adaptive filter 20
Gradually converges toward the optimum solution (the center point of the concentric circles in FIG. 2), but if the difference between the simulated transfer characteristic: G _{E and} the actual transfer characteristic: G is outside the allowable range, the square error is Although the filter coefficient is gradually updated and diverges, the output signal of the adaptive filter 20 is subjected to frequency-doubling processing to obtain a control signal. As shown, since there are two optimum conditions of the adaptive filter 20 having a phase difference relationship of 180 degrees, even if there is only one optimum condition, there are two update paths that cannot be converged. The divergence can be effectively prevented by converging sequentially toward any existing optimal solution (center point of each concentric circle in FIG. 3).

This means that no matter how large the difference between the simulated transfer characteristic: G _{E and} the actual transfer characteristic: G,
The divergence is prevented and the simulated transfer characteristic: G
It means that setting _E is not always necessary. In that case, the reference signal and the simulated transfer characteristic: G
The convolution with _E becomes unnecessary. However, in order to achieve adaptation in a shorter time, it is desirable to set and introduce a simulated transfer characteristic: G _E that is substantially the same as the actual transfer characteristic.

Further, in the image stabilization system of this embodiment, since the sample value sequence is obtained from the frequency-divided signal at a sampling period twice the basic sampling period, the arrangement of the signals in the sample value sequence is the basic sampling frequency. In addition, since this sample value sequence is input to the digital filter 18 at the basic sampling period, the filter based on the error signal according to the residual vibration of the image stabilization target input at the basic sampling period. Corresponding to the coefficient update period, the filter coefficient can be updated in the basic sampling period, so that the digital filter 18 is effectively operated.

Incidentally, in order to confirm the effectiveness of the control system of the antivibration system having the above-mentioned structure, an antivibration control experiment was conducted using a simple experimental model whose schematic configuration is shown in FIG. went. In this simple experimental model, a signal generated by the function generator 32 is used as a detection signal (an input signal and a reference signal) with respect to a signal to be erased as vibration to be isolated which is generated by the function generator 32. Controller operating according to the above embodiment (LMS as adaptive algorithm
By adding the excitation signals as the excitation force obtained by (34), the erasing target signal is canceled and the error signal as the residual vibration is adaptively controlled to be zero. .

Then, using this simple experimental model,
Target frequency: Eliminate the signal containing the frequency component of 20Hz
Simulated transmission characteristics adopted by the controller 34
Gender: G _EFor each of when set to
When the controller 34 is switched from OFF to ON
Error signal and controller output signal time characteristics
The measurement result is shown in FIG. Also, for comparison,
Control according to the conventional method that does not perform processing such as lap and double
According to LA, simulated transmission characteristics: G_EWhen and
Fig. 6 shows the results of similar experiments performed for each of the
Shown in. <Simulated transfer characteristic: G_EBetween the input and output of the controller as
Transfer function settings >> Characteristics with phase difference and gain shown in FIG. Compared to the above, the characteristics that the phase is advanced 180 degrees As shown in FIG. 8, phase difference = 0, gain = 1
Characteristics of

As is apparent from the experimental results shown in FIGS. 5 and 6, in the controller according to the conventional method, the phase difference suddenly diverges when the phase difference exceeds the allowable range. Even if the phase difference greatly deviates, that is, the simulated transmission characteristic: G _E greatly differs from the actual transmission characteristic: G, divergence is prevented and an effective adaptive control effect, that is, a vibration damping effect is exhibited. Is recognized.

The embodiments of the present invention have been described in detail above, but these are literal examples, and the present invention should not be construed as being limited to such specific examples.

For example, in the above-described embodiment, a specific example of the vibration isolation system in which a single frequency component in the vibration isolation target (the body of the automobile) is focused has been described. The present invention can be similarly applied to the case where vibrations of a plurality of frequency components are targeted for vibration isolation as described below. In that case, generally, for each frequency component, the output from the digital filter is calculated, frequency-divided processing is performed, and then the obtained control signals are added together to drive the vibration means. Can be advantageously implemented by calculating the control signal of An example of the configuration system in such a case is shown in FIGS. 9 and 10. Figure 9
10 shows an example in which an adaptive digital filter is used for each of the frequency components to be image stabilization, and FIG. 10 shows an example in which one adaptive digital filter is used. However, there is no difference in the purpose. In FIG. 9, DF is a digital filter
DF shows an adaptive filter, and FIG.
DF1 and DF2 are the first digital filter and the second digital filter, and ADF1 and ADF2.
Defines a first adaptive filter and a second adaptive filter,
Shown respectively.

Further, the present invention is also applied to a vibration damping means for exerting a vibration force on a vibration-proof object, or a vibration-proof system provided with a plurality of error sensors for detecting residual vibration of the vibration-proof object. It is possible to implement such a multi-channel image stabilization system by inserting and performing the frequency division, duplication, and frequency multiplication processes similar to those in the above-described embodiment in the signal processing process. .

Furthermore, in the present invention, JP-A-63 is used.
No. 23616, Japanese Patent Laid-Open No. 63-23617,
It is also possible to employ the signal matrix parallelization method disclosed in Japanese Patent Laid-Open No. 63-23618, etc., whereby the control can be further stabilized and speeded up.

Further, as the vibrating means, the frequency of the generated vibrating force is double the frequency of the supplied control signal by utilizing the attractive force (magnetic force) exerted on the magnetic body by the electromagnet coil. If the output signal is directly input to the vibrating means, the vibrating means itself performs the frequency-doubling processing. Therefore, it is not necessary to add special frequency-doubling processing to the output signal. Absent. That is,
2 of the frequency of the control signal supplied with the frequency of the generated exciting force
If the oscillating means for doubling is adopted, the oscillating means itself constitutes the doubling means.

Further, in the above embodiment, the two sample value sequences (a) and (b) obtained by duplication are alternately input to the digital filter 18 at the basic sampling period. Alternatively, it is also possible to carry out the adaptive control as described above by using only one of the sample value sequences (a) and (b) without duplication and inputting it to the digital filter 18. It is possible. However, in that case, since the sampling period of the sample value sequence is twice the basic sampling period, the same sample value sequence is input twice to input the sample value sequence to the digital filter 18 at the basic sampling period. It is necessary to input continuously one by one.

Further, in the above-mentioned embodiment, the vibrating means is incorporated in the engine mount, but the vibrating means for exerting a vibrating force on the vibration-proof object can be constructed independently of the mount.

Further, in the above-mentioned embodiment, a specific example of the present invention applied to a vibration isolation system of an automobile is shown. However, the present invention can be applied to the vibration isolation system of various devices in addition to the vibration isolation system. If the object to be shaken is the atmosphere in the predetermined space,
It can also be applied to soundproof systems in sound fields.

Although not listed one by one, the present invention is
Based on the knowledge of those skilled in the art, it can be implemented in various modified, modified, and improved modes, and
It goes without saying that such embodiments are included within the scope of the invention.

[0041]

As is apparent from the above description, according to the present invention, when the vibration of the vibration-proof object is actively suppressed by adaptively controlling the vibrating means, the setting of the simulated transfer characteristic in the vibration transfer system is set. It is possible to effectively prevent the divergence of the control system due to a large error, and thereby it is possible to stably obtain the desired anti-vibration effect.

Further, if the two sample value sequences obtained by doubling the frequency-divided signal are alternately input to the adaptive digital filter at the basic sampling period, the update of the filter coefficient in the appropriate type digital filter is performed. It is possible to respond to the change of the input signal, that is, the vibration state of the image stabilization target, more advantageously and quickly, and it is possible to obtain a more effective image stabilization effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a vibration isolation system as an embodiment of the present invention in which the present invention is applied to a vehicle vibration isolation system.

FIG. 2 is an explanatory diagram for explaining an adaptation / divergence process in the method of least squares according to a conventional method without performing frequency multiplication processing.

FIG. 3 is an explanatory diagram for explaining an adaptation process in the image stabilization system shown in FIG.

FIG. 4 is a block diagram showing a schematic configuration of a model of a simple experiment conducted for confirming the effectiveness of the image stabilization system according to the present invention.

5 is a graph showing the results of an experiment according to the present invention performed using the simplified experimental model shown in FIG.

FIG. 6 is a graph showing, as comparative example results, an experimental result according to a conventional technique performed using the simple experimental model shown in FIG. 4.

FIG. 7 is a graph showing a phase difference and a gain in one simulated transfer characteristic adopted in an experiment using the simple experimental model shown in FIG.

FIG. 8 is a graph showing a phase difference and a gain in another simulated transfer characteristic adopted in an experiment using the simple experimental model shown in FIG.

FIG. 9 is a block diagram schematically showing a specific example according to the present invention of a vibration isolation system in which vibrations of a plurality of frequency components are targeted for vibration isolation.

FIG. 10 is a block diagram schematically showing another specific example according to the present invention of a vibration isolation system in which vibrations of a plurality of frequency components are targeted for vibration isolation.

[Explanation of symbols]

12 body 14 power units 16 engine mount 18 Digital filter 20 Adaptive filter 26 Error sensor

Continuation of the front page (56) Reference JP-A-6-74293 (JP, A) JP-A-5-288238 (JP, A) JP-A-6-274185 (JP, A) JP-A-5-188973 (JP , A) JP-A-6-149269 (JP, A) JP-A-6-266376 (JP, A) Special Table 1-501344 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) F16F 15/00-15/08 G05D 19/02 G10K 11/16 G10K 11/178

Claims (3)

(57) [Claims] 1. An adaptive digital filter for controlling a vibrating means for exerting a vibrating force on an object to be isolated on the basis of an input signal having a frequency component corresponding to vibration to be isolated, and the adaptive digital filter. In the active vibration control device that adaptively controls the vibration applying means by updating the filter coefficient of the filter in a direction to reduce the residual vibration in the vibration isolation target, the frequency of the input signal is divided into ½. Frequency dividing means for generating a divided signal, sampling means for obtaining a sample value sequence having a sampling period twice the basic sampling period from the divided signal, and the sample value sequence for the adaptive digital filter. Sample value input means for inputting at a basic sampling period and the control signal of the vibrating means by obtaining the square value of the output signal of the adaptive digital filter. Active vibration control system, characterized in that the fold dividing means for generating, provided. 2. Sequentially allocating sampling values sampled at the basic sampling cycle from the frequency-divided signal to form two sample value sequences each having a sampling cycle twice the basic sampling cycle and different phases from each other. The sampling means is configured to include the duplication processing means for performing the sampling process, and the two sample value sequences generated by the duplication processing means by the sample value input means are supplied to the adaptive digital filter as a basic sampling period. 2. The active vibration control device according to claim 1, wherein the input is made alternately with. 3. An adaptive digital filter for controlling a vibrating means for exerting a vibrating force on a vibration-damping target object based on an input signal having a frequency component corresponding to a vibration to be vibration-damped.
When adaptively controlling by updating the filter coefficient of the adaptive digital filter in the direction of reducing the residual vibration in the image stabilization target, the frequency of the input signal is divided into ½ to generate a divided signal. , A sample value sequence having a sampling period twice the basic sampling period is obtained from the frequency-divided signal, and the sample value sequence is input to the adaptive digital filter at the basic sampling period while the appropriate type digital filter is used. An active vibration control method, characterized in that a square value of the obtained output signal is obtained and used as a control signal for the vibrating means.