JPH0659684A - Active vibration controller - Google Patents

Abstract

PURPOSE:To obtain an active, vibration controller which actively controls a noise due to vibration, so that a noise reducing effect can be obtained immediately from the time of the start of use. CONSTITUTION:A noise, which was detected by a noise sensor 1, is inputted into an adaptive filter 2 as a reference signal. The mean value of the values, which were obtained in advance by measurement or the like, is set to the adaptive filter 2 as an initial value. When the control is started, a cancel noise is generated from a speaker 3 at first, so that the vibration is almost removed. The vibration, which is not removed by this cancel noise, is fed back to the adaptive filter 2 as an error signal epsilon. In the adaptive filter 2, using both reference signal and error signal epsilon, a coefficient value of the adaptive filter 2 is updated, so that a new cancel signal is produced. In addition, a cancel noise corresponding to the cancel signal is generated, so that such control as to minimize the error signal epsilon is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active vibration control system for actively controlling and reducing vibrations of transportation means such as vehicles and airplanes and noises caused by these vibrations.

[0002]

2. Description of the Related Art In the present invention, the term "vibration" is used to include "noise".

Among the vibration control devices, there is one called an active vibration control device for reducing the vibration and noise by attenuating the vibration generated from the vibration source (noise source).

Conventionally, as an active vibration control device of this kind, a vibration detecting means for detecting a vibration from a vibration source, a vibration detected by the vibration detecting means are inputted as a reference signal, and the vibration of the reference signal is inputted. Control means for generating a canceling signal having a transfer characteristic having a phase opposite to that of the transfer characteristic by using an adaptive filter; canceling vibration generating means for generating canceling vibration based on the canceling signal generated by the control means; An error signal detecting means for detecting a canceling error between the canceling vibration generated by the canceling vibration generating means and the vibration from the vibration source is provided, and the error signal detected by the error signal detecting means is set to a minimum value. An active vibration control device that controls the transfer characteristic of a cancellation signal is known (for example, Japanese Patent Publication No.
No. 501344).

In the active vibration control device disclosed in the above Japanese Patent Publication No. 1-501344, the control means has two FIR adaptive digital filters (ADF; hereinafter referred to as "adaptive filter") built therein, and a fundamental frequency. And the specific frequency of its harmonics are selected and processed.

In the above control means, an LMS algorithm (LMS: Least Mea) is used as an adaptive algorithm (calculation method) for generating the optimum cancellation signal.
nSquare) is commonly used.

[0007]

However, in the above-mentioned conventional active vibration control device, since the initial value of the filter coefficient of the adaptive filter is 0, for example, the active vibration control device mounted on the vehicle is shipped after the vehicle is shipped. When used for the first time, it is difficult to obtain the vibration reduction effect, and with subsequent use of the device, the filter coefficient value of the adaptive filter converges to a value according to the vibration that should be canceled, and eventually the required vibration reduction effect is obtained. Will be available. As described above, the conventional active vibration control device has a problem that the convergence time is long until the canceling signal that sufficiently cancels the vibration is generated.

The present invention has been made in view of the above problems, and an object thereof is to provide an active vibration control device which can obtain a desired noise reduction effect immediately after the start of use.

[0009]

To achieve the above object, the present invention inputs a signal highly related to vibration from a vibration source as a reference signal, and has a phase opposite to the vibration transfer characteristic from the vibration source. Control means for generating a canceling signal having a transfer characteristic using an adaptive filter, canceling vibration generating means for generating canceling vibration based on the canceling signal generated by the controlling means, and canceling vibration generating means An error signal detecting means for detecting a canceling error between the canceling vibration and the vibration from the vibration source is provided, and the transfer characteristic of the canceling signal is controlled so that the error signal detected by the error signal detecting means becomes a minimum value. In the active vibration control device, a value for generating a cancellation signal having a predetermined vibration transfer characteristic according to the vibration to be canceled is obtained in advance as the value of the adaptive filter, and the obtained value is an initial value. Characterized in that it comprises set to the adaptive filter by. When the engine noise is targeted, for example, the initial value is a value suitable for canceling the vibration generated during the warm-up operation of the vehicle.

Further, according to the present invention, a signal highly related to the vibration from the vibration source is input as a reference signal, and a canceling signal having a transfer characteristic opposite in phase to the vibration transfer characteristic from the vibration source is adaptively filtered. A canceling vibration generating means for generating a canceling vibration based on a canceling signal generated by the controlling means, and a canceling vibration generated by the canceling vibration generating means and a vibration from the vibration source. In the active vibration control device for controlling the transfer characteristic of the canceling signal so that the error signal detected by the error signal detecting means has a minimum value. A filter value for generating a cancellation signal having a predetermined vibration transfer characteristic according to vibration is obtained in advance, and a fixed filter in which the obtained filter value is set is used together with the adaptive filter. And wherein the door.

[0011]

According to the above-mentioned structure, in the invention according to claims 1 and 2, the control means has a predetermined vibration transfer characteristic immediately after the start of use of the device, by the adaptive filter in which an initial value obtained in advance is set. A canceling signal is generated, and the canceling vibration generating means generates canceling vibration in response to the canceling signal. An offset error between the offset vibration and the vibration from the vibration source is detected by the error detection means, and the transfer characteristic of the offset signal is controlled so that the detected offset error becomes a minimum value.

According to a third aspect of the present invention, the control means generates a canceling signal having a predetermined transfer characteristic by the fixed filter having an initial value determined in advance at the start of use of the device, and the error detecting means causes the canceling signal to be generated. The transfer characteristic of the cancellation signal is controlled so that the detected cancellation error has a minimum value.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of an active vibration control device according to the present invention.

As shown in FIG. 1, the active control system of this embodiment receives a noise sensor 1 for detecting noise from a noise source (vibration source), and noise detected by the noise sensor 1 as a reference signal. Also, the adaptive filter 2 that generates a canceling signal having a transfer characteristic having a phase opposite to that of the reference signal, the speaker 3 that emits a canceling sound based on the canceling signal generated by the adaptive filter 2, and the speaker 3 The microphone 4 for detecting an error between the emitted canceling sound and the reference signal is mainly configured. However, the speaker amplifier, the microphone amplifier, and the noise sensor amplifier are omitted from this figure.

The noise (primary noise) detected by the noise sensor 1 is sampled by the A / D converter 5 and input to the adaptive filter 2 as a standard signal (reference signal) X of digital data. The cancellation signal generated as described above is output from the adaptive filter 2, converted into an analog signal by the D / A converter 6, and cancellation noise (secondary noise) is emitted from the speaker 3.

On the other hand, the microphone 4 receives the canceling sound from the speaker 3, the canceling sound is sampled by the A / D converter 7, extracted as an error signal ε of digital data, and fed back to the adaptive filter 2.
That is, the error signal indicates a canceling error between the primary noise and the secondary noise, and the adaptive filter 2 changes the transfer characteristic of the opposite phase of the canceling signal so that the error signal becomes the minimum value, thereby reducing the noise. Reduce.

In the adaptive filter 2, an LMS algorithm (LMS: Least) is used as an adaptive algorithm (calculation method) for generating an optimum cancellation signal.
Mean Square) is used.

The configuration of FIG. 1 described above is substantially the same as that described in the conventional example, but in the conventional example, the initial value of the filter coefficient of the adaptive filter 2 is 0.
The present embodiment is different in that the initial value is preset to a value that generates a cancellation signal having a predetermined vibration transfer characteristic.

The above-mentioned initial value is set in advance, for example, by measurement when developing a transportation system in which the active vibration control device is used. That is, first, with the filter coefficient value of the adaptive filter being 0, a transportation facility equipped with an active vibration control device,
For example, when targeting road noise generated when driving on a rough road surface, whether the vehicle actually runs on the actual road,
Alternatively, by traveling on a chassis dynamometer equipped with a road noise road surface, the value when the filter coefficient value of the adaptive filter changes from 0 and is converged and becomes substantially constant is measured. Therefore, when the vehicle is mass-produced, the measured filter coefficient value is input to the adaptive filter of the active vibration control device mounted on the mass-produced vehicle. The initial value of the set filter coefficient is set in advance to the average value of a plurality of measurement values obtained by experimental measurement. However, since the transmission characteristics of vibration and the like vary from vehicle to vehicle due to manufacturing variations and the like, it is not possible to minimize the vibration with the initial value set to the above average value. The convergence time of the filter coefficient value is much shorter than that when the device is started to be used, and a substantially required silencing effect can be immediately obtained from the start of use of the device.

As described above, the vibration cannot be completely canceled by the above-mentioned initial value, but the filter coefficient value is updated by the vibration control of the device thereafter, and the value is converged to the required value within a short time, resulting in sufficient noise reduction. The effect will be achieved.

FIG. 2 is a block diagram showing a schematic configuration of the second embodiment of the active vibration control system according to the present invention. This embodiment is different from the first embodiment in that the fixed filter 8
The same reference numerals are given to the elements common to FIG. 1, and detailed description of the configuration and operation will be omitted.

In FIG. 2, the fixed filter 8 is interposed between the A / D converter 5 and the adaptive filter 2. The filter coefficient value of the fixed filter 8 is set to a value experimentally measured in advance, as in the first embodiment described above.

The noise detected by the noise sensor 1 is A
After being converted into a reference signal X as digital data by the / D converter 5, it is input to the fixed filter 8. The fixed filter 8 is a filter capable of outputting a canceling signal that controls a predetermined vibration, for example, a canceling signal that minimizes a vibration in a predetermined frequency range. The reference signal X is filtered by the fixed filter 8 to become a reference signal X ′. , The reference signal X ′ is supplied to the adaptive filter 2. By using this fixed filter 8, at the start of use of the device, a predetermined sound deadening effect is immediately obtained from the start of use, as in the first embodiment described above.

In the first embodiment, the filter coefficient of the adaptive filter 2 is determined so that the predetermined canceling signal is output only when the device is started to be used, and as the control progresses, the filter coefficient is sequentially increased so as to minimize the error signal. In the present embodiment, the fixed filter 8 cancels a predetermined vibration based on the vibration from the noise source (vibration source) at the start of use of the device, and only the vibration component that cannot be canceled is applied. The cancellation is controlled by the adaptive control of the filter 2. The filter coefficient of the adaptive filter 2 is updated by this adaptive control. As described above, in this embodiment, since the fixed filter 8 supplies the signal X ′ for canceling a predetermined vibration to the adaptive filter 2 from the start of use of the apparatus, the load on the adaptive filter 2 is significantly reduced. , The convergence time until the error signal ε is minimized is significantly shortened.

When a filter for canceling random vibration is used as the fixed filter 8, when the vibration to be cancelled is a combined vibration of periodic vibration and random vibration, the adaptive filter 2 only removes the periodic vibration. It has the effect of being able to devote itself to the task and greatly improving the followability.

In this embodiment, the fixed filter 8 is set to A /
I inserted between the D converter 5 and the adaptive filter 2,
Instead of this, a similar effect can be obtained by inserting between the adaptive filter 2 and the D / A converter 6.

The value of the filter coefficient of the fixed filter 8 is determined by the vibration transfer characteristics of the control system used in the experiment. As a method for obtaining the vibration transfer characteristics, for example, off-line identification such as maximum likelihood method is used. Method or a method of estimating a vibration transfer characteristic from a reference signal input and an output vibration signal by an online identification method such as the LMS method, or a method of directly calculating from a motion equation using a finite element method or the like. it can.

Furthermore, the filter coefficient value of the fixed filter 8 may be set to a value that enables the output of a canceling signal that minimizes vibration in a single predetermined frequency range, or for each of a plurality of different predetermined frequency ranges. A plurality of filter coefficient values determined so that a cancellation signal that minimizes the vibration can be output is stored in a memory, and a filter coefficient value according to the frequency of the vibration to be canceled during control is read from the memory and fixed. It may be a filter coefficient value of the filter 8.

[Application Example] FIG. 3 shows an application of the active vibration control device according to the present invention to a road noise control device for a vehicle (a device for reducing road noise when the vehicle is running due to unevenness on the road surface). FIG. 11 is a block diagram showing a schematic configuration of an example of a case, and in this application example, a noise sensor including two acceleration pickups and the like is mounted on the vehicle body for each one wheel as a noise source (vibration source). Has been done.

In practice, eight noise sensors are mounted on a suspension system of a vehicle body having four wheels, but in FIG. 3, the right wheel of the vehicle is used as a noise source for convenience of description. only pieces of noise sensors 10 ₁ to 10 ₄ is illustrated.

In this application example, noise sensors 10 ₁ to 10 ₄ and
A / D converter 11 ₁ to 11 ₄ for converting the signal obtained by the noise sensor 10 ₁ to 10 ₄ to the digital signal x ₁ ~x ₄
And adaptive control circuits 12 _{1 to} 12 ₄ that generate cancellation signals that use digital signals x _{1 to} x ₄ as reference signals to minimize error signals e ₁ and e ₂ described later, and adaptive control circuits 12 _{1 to} 12 _Four
Output signals y _{11 to} y ₁₄ and y _{21 to} y ₂₄ of the adders 13 ₁ and 13 ₂ and the digital output signals u ₁ and u ₂ of the adders 13 ₁ and 13 ₂ are converted into analog signals. / A converters 14 ₁ and 14 ₂ and D / A converters 14 ₁ and 1
Speakers 15 ₁ and 15 ₂ that convert the canceling signal output from 4 ₂ into canceling sound, and a microphone 16 that detects a canceling error between vehicle interior noise (temporary noise) and the canceling sound (secondary noise).
₁ and 16 ₂ and A / D converters 17 ₁ and 17 ₂ for converting error signals as analog data detected by the microphones 16 ₁ and 16 ₂ into digital signals e ₁ and e ₂ .

The adaptive control circuit 12 ₁ includes four FIR filters 18 for compensating for delay characteristics peculiar to this control system from the corresponding noise sources to the corresponding microphones 16 ₁ and 16 _2.
111 to 18 ₁₂₂ (The filter coefficient is C ₁₁ (∧), respectively)
˜C ₂₂ (∧)) and adaptive coefficients 19 ₁₁ and 19 ₁₂ that generate a cancellation signal from the reference signal x ₁ based on the filter coefficients W ₁₁ and W ₂₁ and FIR filters 18 ₁₁₁ to 18 ₁₂₂ . Based on the reference signal x ₁ and the error signals e ₁ and e ₂ , the reference signal x ₁ , that is, the microphone 1 from the noise source.
The transfer characteristics of the opposite phase (reverse transfer characteristics) are calculated with respect to the transfer characteristics up to 6 ₁ and 16 ₂ , and adaptive filters 19 ₁₁ and 19 ₁₂
MEFXLMS processing units 20 ₁₁ and 20 ₁₂ for updating the filter coefficients W ₁₁ and W ₂₁ of the above.

[0034] MEFX LMS processing unit 20 _11, 20
₁₂ is MEFX (Multiple Err) as an adaptive algorithm.
or Filtered-X) LMS algorithm, and the reference signal x ₁ and the error signals e ₁ and e ₂ filtered by the FIR filters 18 ₁₁₁ to 18 ₁₂₂ by the algorithm.
In order to generate the optimum cancellation signal from the above, the inverse transfer characteristic is calculated, and based on the calculation result, the adaptive filters 19 ₁₁ , 1
The control for updating the filter coefficients W ₁₁ and W ₂₁ of 9 ₁₂ is executed.

Further, the initial values of the filter coefficients W ₁₁ and W ₂₁ of the adaptive filters 19 ₁₁ and 19 ₁₂ are set to values experimentally measured in advance.

Similarly, the adaptive control circuit 12n (n =
2, 3, 4) are FIR filters 18n _{11 to} 18n
₂₂ , adaptive filters 19n ₁ and 19n ₂ , and MEFX L
The MS processing units 20n ₁ and 20n ₂ (n = 2, 3, 4).

The control operation of this application example will be described in detail below.

[0038] In FIG. 3, the noise signals picked up by the noise sensor 10 ₁ to 10 ₄ is converted to the reference signal x ₁ ~x ₄ as digital data via the respective A / D converters 11 ₁ to 11 ₄ .

The reference signals x _{1 to} x ₄ are _first converted into filter coefficients W of the adaptive filters 19 ₁₁ , 19 ₂₁ , 19 ₃₁ , 19 ₄₁ , respectively.
Multiplied by ₁₁ , W ₁₂ , W ₁₃ , and W ₁₄ , the digital signal y
₁₁ (= W ₁₁ x ₁ ), y ₁₂ (= W ₁₂ x ₂ ), y ₁₃ (= W ₁₃ x
₃ ) and y ₁₄ (= W ₁₄ x ₄ ) are generated.

Next, digital signals y ₁₁ , y ₁₂ , y ₁₃ , y
₁₄ is added by the adder 13 ₁ , and the digital signal u ₁ (=
y ₁₁ + y ₁₂ + y ₁₃ + y ₁₄ ) is generated. The signal u
₁ is analog-converted by the D / A converter 14 ₁ ,
The sound U ₁ is propagated to the space through the speaker 15 ₁ .

Similarly, the digital signals x _{1 to} x ₄ are multiplied by the filter coefficients W ₂₁ , W ₂₂ , W ₂₃ , W ₂₄ of the adaptive filters 19 ₁₂ , 19 ₂₂ , 19 ₃₂ , 19 _{42 to} obtain the digital signal y. ₂₁ (= W ₂₁ x ₁ ), y ₂₂ (= W ₂₂ x ₂ ), y ₂₃ (= W ₂₃
x ₃ ), y ₂₄ (= W ₂₄ x ₄ ) is generated, and the digital signal u ₂ (= y ₂₁ + y ₂₂ + y ₂₃ + y ₂₄ ) is added via the adder 13 _2.
Similarly, the signal u ₂ is analog-converted by the D / A converter 14 ₂ and propagated to the space as the sound U ₂ via the speaker 15 ₂ .

From the speaker 15 ₁ to the microphones 16 ₁ , 1
When the transfer functions in the space up to 6 ₂ are C ₁₁ and C ₂₁ , respectively, and the transfer functions in the space from the speaker 15 ₂ to the microphones 16 ₁ and 16 ₂ are C ₁₂ and C ₂₂ , respectively, input by the microphones 16 ₁ and 16 _2. The generated signals E ₁ and E ₂ are as follows.

E ₁ = C ₁₁ U ₁ + C ₁₂ U ₂ + H ₁₁ X ₁ + H ₂₁ X
₂ + H ₃₁ X ₃ + H ₄₁ X ₄ E ₂ = C ₂₁ U ₁ + C ₂₂ U ₂ + H ₁₂ X ₁ + H ₂₂ X ₂ + H ₃₂ X ₃ +
H ₄₂ X ₄ However, Hij is a propagation characteristic that directly propagates from the noise sensors 10 ₁ to 10 ₄ to the microphones 16 ₁ and 16 ₂ .

The analog signals E ₁ and E ₂ are respectively A
The / D converters 16 ₁ and 16 ₂ convert the error signals e ₁ and e ₂ which are digital signals.

The error signals e ₁ and e ₂ are transmitted to the FIR filter 1
The reference signal x ₁ from 8 ₁₁₁ , 18 ₁₂₁ is C ₁₁ (∧) and C
Signal C ₁₁ (∧) x ₁ and C ₂₁ corrected by ₂₁ (∧)
(∧) x ₁ is input to the MEFX LMS processing unit 20 ₁₁ and is calculated by the MEFX LMS algorithm, and the filter coefficient of the adaptive filter 19 ₁₁ is W ₁₁ so as to minimize the values of the error signals e ₁ and e _2. Is determined and updated.

Similarly, the filter coefficients W _{12 to} W ₁₄ , W
_{21 to} W ₂₄ are updated, and these updated filter coefficients W
signal Y by nm (n = 1,2; m = 1,2,3,4)
nm (= Wnm · xm) (n = 1,2; m = 1,2,
3, 4) are updated. Next, the adders 13 ₁ and 13 ₂ generate the signals u ₁ and u ₂ , respectively, and the D / A converters 14 ₁ and
14 ₂ and the speakers 15 ₁ and 15 ₂ through the signals e ₁ and e
_The canceling sounds U ₁ and U ₂ that minimize ₂ are propagated to the space, interfere with the vibration sound existing in the space, and the silencing control is performed.
The vibrations that are not removed by the canceling sound are input to the sound collecting microphones 16 ₁ and 16 ₂ again, and control is performed so as to sequentially minimize the vibrations in the space according to the control procedure described above.

The initial values of the filter coefficients W _{11 to} W ₂₄ of the adaptive filters 19 _{11 to} 19 ₄₂ are the initial value memories M _{11 to} M _24.
It is stored in. The values of the initial value memories M _{11 to} M ₂₄ are set so that, for example, when engine noise is targeted, so-called muffled noise generated by vibration of the engine when one vehicle occupant performs warm-up operation is sufficiently removed. First, the engine is operated under conditions that simulate such a case in advance, the coefficient values of the adaptive filter are measured, and the average value is obtained. Then, the active vibration control is started, for example, when 3 seconds have passed after the engine was started, that is, when the engine speed reached the warm-up speed. In this way, when the engine is started and 3 seconds have passed, the operation of this device is started and the initial value memories M _{11 to} M
_The cancellation signal generated by the initial value read from ₂₄ is output, converted into an analog signal through the D / A converters 14 ₁ and 14 _2, and cancellation sounds are emitted from the speakers 15 ₁ and 15 ₂ . Since the initial value of the coefficient of the adaptive filter is set as described above, a substantially sufficient silencing effect can be obtained from the first use of the device. The start point of vibration control is
Instead of 3 seconds after starting the engine, the starter switch may be turned off.

As described above, the adaptive filters 19 ₁₁ ...
By adopting a value that minimizes the average vibration during warm-up operation of the same vehicle type as the initial value of the coefficient of 19 ₄₂ , the required silencing effect can be immediately obtained from the start of use of the device, and , MEFX LMS processing unit 20 _{11-20
Since the control for 42} only needs to cancel the vibration that cannot be removed by this initial value, the convergence time until a substantially complete silencing effect is obtained is greatly shortened.

In the present application example, the initial value is set to a value that minimizes the vibration during warm-up operation of a single passenger, but the present invention is not limited to this value. , A plurality of initial values that minimize the vibration are obtained in advance by measurement and stored in the memory, and the initial value according to the rotation speed at the start of control is read from the memory and used as the initial value of the filter coefficient of the adaptive filter. May be.

In this case, as described above, the vibration control is started when the engine reaches each predetermined rotation speed.

Of course, even when the fixed filter shown in FIG. 2 is used in combination with the adaptive filter, it is possible to set the initial value and the control start point as described above.

[0052]

As described above, according to the present invention, a signal highly related to vibration from a vibration source is input as a reference signal, and a transfer characteristic having a phase opposite to that of the vibration transfer characteristic from the vibration source is input. Control means for generating a canceling signal using an adaptive filter, canceling vibration generating means for generating canceling vibration based on the canceling signal generated by the controlling means, canceling vibration generated by the canceling vibration generating means, and An active vibration control that includes an error signal detection unit that detects a cancellation error with a vibration from a vibration source, and controls the transfer characteristic of the cancellation signal so that the error signal detected by the error signal detection unit has a minimum value. In the apparatus, as the value of the adaptive filter, a value for generating a cancellation signal having a predetermined vibration transfer characteristic according to the vibration to be canceled is obtained in advance, and the obtained value is used as an initial value for the adaptive filter. The filter value for generating a canceling signal having a predetermined vibration transfer characteristic corresponding to the vibration to be canceled is obtained in advance, and a fixed filter having the obtained filter value is used together with the adaptive filter. Therefore, it is possible to remove the vibration having a predetermined vibration characteristic from the time when the control is started, and it is possible to shorten the convergence time until the cancellation signal that sufficiently cancels the vibration is generated.

Further, by taking a value that generates a cancellation signal for canceling the vibration during the warm-up operation of the vehicle as the initial value, the vibration peculiar to the warm-up operation can be removed from the start of the control.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of an active vibration control device according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a second embodiment of the active vibration control device according to the present invention.

FIG. 3 is a block diagram showing a schematic configuration of an application example in which the active vibration control device according to the present invention is applied to a road noise canceller.

[Explanation of symbols]

 1 Noise Sensor (Vibration Detection Means) 2 Adaptive Filter (Control Means) 3 Speaker (Cancellation Vibration Generation Means) 4 Microphone (Error Signal Detection Means) 8 Fixed Filter

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[Procedure amendment]

[Submission date] September 2, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Active vibration control device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active vibration control system for actively controlling and reducing vibrations of transportation means such as vehicles and airplanes and noises caused by these vibrations.

[0002]

2. Description of the Related Art In the present invention, the term "vibration" is used to include "noise".

Among the vibration control devices, there is one called an active vibration control device for reducing the vibration and noise by attenuating the vibration generated from the vibration source (noise source).

Conventionally, as an active vibration control device of this kind, a vibration detecting means for detecting a vibration from a vibration source and a vibration detected by the vibration detecting means are inputted as a reference signal and adapted to the reference signal. A control unit that generates a cancellation signal by filtering the reference signal using a filter, a cancellation vibration generation unit that generates a cancellation vibration based on the cancellation signal generated by the control unit, and a cancellation vibration generation unit. An error signal detection unit that detects a cancellation error between the generated cancellation vibration and the vibration from the vibration source is provided, and the cancellation signal is controlled so that the power of the error signal detected by the error signal detection unit is minimized. There is known an active vibration control device.

In the active vibration control device disclosed in Japanese Patent Publication No. 1-501344, the control means is FI.
An R adaptive digital filter (ADF: hereinafter referred to as “adaptive filter”) is built in, and processing is performed only on specific frequencies of the fundamental frequency and its harmonics.

In the above control means, an LMS (Least Mean Square) algorithm is generally used as the adaptive algorithm (filter coefficient update rule of the adaptive filter).

[0007]

However, in the above-mentioned conventional active vibration control device, since the initial value of the filter coefficient of the adaptive filter is 0, for example, the active vibration control device mounted on the vehicle is shipped after the vehicle is shipped. When used for the first time, it is difficult to obtain the vibration reduction effect, and with subsequent use of the device, the filter coefficient value of the adaptive filter converges to a value according to the vibration that should be canceled, and eventually the required vibration reduction effect is obtained. Will be available. As described above, the conventional active vibration control device has a problem that it takes a long time to generate the cancellation signal that sufficiently cancels the vibration.

The present invention has been made in view of the above problems, and an object thereof is to provide an active vibration control device which can obtain a desired noise reduction effect immediately after the start of use.

[0009]

In order to achieve the above object, the present invention inputs a signal having a high correlation with vibration from a vibration source as a reference signal, and filters the reference signal using an adaptive filter. Control means for generating a canceling signal by the canceling vibration generating means for generating a canceling signal on the basis of the canceling signal generated by the controlling means, canceling vibration generated by the canceling vibration generating means, and vibration from the vibration source. And an error signal detecting means for detecting a canceling error of the vibration signal from the vibration source by controlling the canceling signal so that the power of the error signal detected by the error signal detecting means is minimized. In the active vibration control device to be controlled, the filter characteristic (filter coefficient value) for generating a predetermined canceling signal according to the vibration to be canceled is calculated in advance. It characterized in that to set as the initial characteristic filter characteristics to the adaptive filter.

Further, according to the present invention, control means for inputting a signal having a high correlation with vibration from a vibration source as a reference signal, and for generating a canceling signal by filtering the reference signal using an adaptive filter, Canceling vibration generating means for generating canceling vibration based on the canceling signal generated by the controlling means, and error signal detection for detecting a canceling error between the canceling vibration generated by the canceling vibration generating means and the vibration from the vibration source. Means for controlling the canceling signal so that the power of the error signal detected by the error signal detecting means is minimized, thereby canceling the vibration from the vibration source. A filter characteristic that generates a predetermined cancellation signal according to the power vibration is obtained in advance, and the filter that does not change when the characteristic is set (fixed filter) is set. Characterized by using the data) together with the adaptive filter.

[0011]

According to the above-mentioned structure, in the invention according to claim 1, the control means generates the predetermined canceling signal immediately after starting the use of the device by the adaptive filter having the initial characteristic obtained beforehand set therein. The canceling vibration generating means generates canceling vibration in response to the canceling signal. A cancellation error between the cancellation vibration and the vibration from the vibration source is detected by the error detection means, and the transfer characteristic of the adaptive filter that generates the cancellation signal is controlled so that the power of the detected cancellation error is minimized. It

According to a second aspect of the present invention, the control means generates a predetermined canceling signal by a fixed filter having an initial characteristic obtained in advance at the start of use of the apparatus, and the canceling detected by the error detecting means. The transfer characteristic of the adaptive filter that generates the cancellation signal is controlled so that the error power has a minimum value.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of an active vibration control device according to the present invention.

As shown in FIG. 1, the active control apparatus of this embodiment includes a reference signal sensor 1 for detecting noise from a noise source (vibration source), and noise detected by the reference signal sensor 1 as a reference signal. An adaptive filter 2 for generating a cancellation signal by inputting and filtering the reference signal,
A speaker 3 that emits a canceling sound based on the canceling signal generated by the adaptive filter 2 and a microphone 4 that detects an error between the canceling sound generated by the speaker 3 and noise from the noise source are mainly configured. ing. However, a power amplifier for driving the speaker, a microphone amplifier,
The noise sensor amplifier is omitted from this figure.

The noise detected by the reference signal sensor 1 is sampled by the A / D converter 5 and input to the adaptive filter 2 as a reference signal X of digital data. The cancellation signal generated as described above is output from the adaptive filter 2, converted into an analog signal by the D / A converter 6, and the cancellation sound is emitted from the speaker 3.

On the other hand, the microphone 4 detects the sum (cancellation error) of the noise from the noise source (vibration source) and the cancellation sound from the speaker 3, and the cancellation error is sampled by the A / D converter 7 and digitally The data error signal ε is taken out and fed back to the adaptive filter 2. The adaptive filter 2 reduces noise by adjusting the filter coefficient so that a canceling sound whose amplitude is the same as noise and whose phase is inverted is generated. Note that the filter 10
Is a fixed filter having a transfer characteristic from the speaker 3 to the microphone 4. The filter 10 has a different purpose from the fixed filter described in the present invention.

Further, in the constituent element 8 of the adaptive filter 2, the LMS algorithm (LM) is used as an adaptive algorithm (calculation method) for generating the optimum cancellation signal.
S: Least Mean Square) is used.

The configuration of FIG. 1 described above is substantially the same as that described in the conventional example, but in the conventional example, the initial value of the filter coefficient W of the digital filter 9 which is a constituent element of the adaptive filter 2 is 0. On the other hand, in the present embodiment,
The difference is that the initial value is preset to a value that generates a predetermined cancellation signal.

The above-mentioned initial value is set in advance, for example, by measurement when developing a transportation system in which the active vibration control device is used. That is, first, with the filter coefficient value of the adaptive filter being 0, a transportation facility equipped with an active vibration control device,
For example, when targeting road noise generated when driving on a rough road surface, whether the vehicle actually runs on the actual road,
Alternatively, by traveling on a chassis dynamometer equipped with a road noise road surface, the value when the filter coefficient value of the adaptive filter changes from 0 and converges to become substantially constant is measured. Therefore, when the vehicle is mass-produced, the measured filter coefficient value is input to the adaptive filter of the active vibration control device mounted on the mass-produced vehicle. The initial value of the set filter coefficient is set in advance to the average value of a plurality of measurement values obtained by experimental measurement. However, since the transmission characteristics of vibration and the like vary from vehicle to vehicle due to manufacturing variations and the like, it is not possible to minimize the vibration with the initial value set to the above average value. The convergence time of the filter coefficient value is much shorter than that when the device is started to be used, and a substantially required silencing effect can be immediately obtained from the start of use of the device.

As described above, the vibration cannot be completely canceled by the above-mentioned initial value, but the coefficient value of the adaptive filter is updated by the vibration control of the device thereafter and converges to the required value within a short time, which is sufficient. The sound deadening effect will be achieved.

2 and 3 are block diagrams showing a schematic configuration of a second embodiment of the active vibration control system according to the present invention. The present embodiment is different from the structure of the first embodiment in that a fixed filter 11 is added. Therefore, common elements are denoted by the same reference numerals in FIG. 1, and detailed description of the structure and operation is omitted. To do.

In FIG. 2, the fixed filter 11 is an A / D.
It is interposed between the converter 5 and the adaptive filter 2.
The filter coefficient value of this fixed filter 11 is the above-mentioned first value.
Similar to the embodiment, it is set to a value measured in advance. In FIG. 3, a fixed filter 11 is provided between the A / D converter 5 and the filter 10 and between the adaptive filter 2 and the D / A.
It is interposed between the converter 6 and the converter 6. The filter coefficient value of the fixed filter 11 is set to a value measured in advance as in the first embodiment described above.

In the configuration shown in FIG. 2, the noise detected by the reference signal sensor 1 is converted into the reference signal X as digital data by the A / D converter 5, and then input to the fixed filter 11. The fixed filter 11 is a filter capable of outputting a cancellation signal that controls a predetermined vibration, for example, a cancellation signal that minimizes a vibration in a predetermined frequency range. The reference signal X is filtered by the fixed filter 11 to become a reference signal X ′. , The reference signal X ′ is supplied to the adaptive signal processing unit 2. Further, the initial characteristics of the digital filter W are set so that the transfer function thereof has characteristics of amplitude 1 and phase 0. By using the fixed filter 11 and setting the initial value of the digital filter W as described above, at the start of use of the apparatus, as in the first embodiment described above, a predetermined mute is immediately performed from the start of use. Produce an effect. The configuration shown in FIG. 3 is a configuration obtained by equivalently converting the configuration shown in FIG. Therefore, the same effect as the embodiment of FIG. 2 is obtained.

In the first embodiment, the filter coefficient of the digital filter 9 is determined so as to output a predetermined canceling signal only when the device is used, and as the control progresses, the filter coefficient is sequentially increased so as to minimize the error signal. In the present embodiment, the fixed filter 11 cancels a predetermined vibration based on the vibration from the noise source (vibration source) at the start of use of the device, and only the vibration component that cannot be canceled is digitalized. Offset control is performed by the filter 9. The filter coefficient of the digital filter 9 is updated by the adaptive algorithm 8. As described above, in this embodiment, since the fixed filter 11 supplies the signal X ′ for canceling a predetermined vibration to the digital filter 9 from the start of use of the apparatus, the load on the digital filter 9 is significantly reduced. The convergence time until the error signal ε is minimized becomes significantly shorter.

The value of the filter coefficient of the fixed filter 11 is determined by the vibration transfer characteristic of the control system used in the experiment. As a method for obtaining the vibration transfer characteristic, for example, offline identification such as maximum likelihood method is used. Method or a method for estimating a vibration transfer characteristic from an input reference signal and an output vibration signal by an online identification method such as the LMS method,
Alternatively, a method of directly obtaining from the equation of motion using a finite element method or the like can be used.

Furthermore, the filter coefficient value of the fixed filter 11 may be set to a value that enables the output of a canceling signal that minimizes vibration in a single predetermined frequency range, or for each of a plurality of different predetermined frequency ranges. A plurality of filter coefficient values determined so that a cancellation signal that minimizes the vibration can be output is stored in a memory, and a filter coefficient value according to the frequency of the vibration to be canceled during control is read from the memory and fixed. It may be a filter coefficient value of the filter 11.

[Application Example] FIG. 4 shows an active vibration control device according to the present invention applied to a vehicle road noise control device (a device for reducing road noise when a vehicle is running due to unevenness of a road surface). FIG. 11 is a block diagram showing a schematic configuration of an example of a case, and in this application example, a noise sensor including two acceleration pickups and the like is mounted on the vehicle body for each one wheel as a noise source (vibration source). Has been done.

Actually, eight reference signal sensors are mounted on a suspension system of a vehicle body having four wheels, but for convenience of explanation, the right wheel of the vehicle is used as a noise source in FIG. Four
Only pieces of the reference signal sensor 10 ₁ to 10 ₄ is illustrated.

In this application example, the fixed filters 21 _{1 to} 21 ₈ are used in combination with the digital filters 19 _{11 to} 19 _42, and the signals obtained by the reference signal sensors 10 ₁ to 10 ₄ are converted into digital signals x _{1 to} x. A / D converter 11 to convert to _{4
1 to} 11 ₄ and adaptive signal processing units 12 _{1 to} 12 ₄ that generate cancellation signals that minimize the sum of powers of error signals e ₁ and e ₂ , which will be described later, using digital signals x _{1 to} x ₄ as reference signals, Output signals y _{11 to} y ₁₄ and y _{21 of the} adaptive signal processing units 12 _{1 to} 12 _4.
An adder 13 _1, 13 ₂ for adding ~y ₂₄ respectively, an adder 13 _1, 13 ₂ of the digital output signal u _1, D / A converter 14 ₁ converts the u ₂ into an analog signal, 14 _2, D /
Speakers 15 ₁ and 15 ₂ that convert the canceling signals output from the A converters 14 ₁ and 14 ₂ into canceling sounds, and a microphone 16 ₁ that detects a canceling error between the vehicle interior noise and the canceling sounds.
16 ₂ and error signals as analog data detected by the microphones 16 ₁ and 16 ₂ are converted into digital signals e ₁ and
It is composed of A / D converters 17 _{1 to} 17 ₄ for converting into e ₂ .

In this application example, the adaptive algorithm is
The MEFX-LMS algorithm is used. The adaptive signal processing unit 12 ₁ has four digital filters 18 ₁₁₁ to 18 ₁₂₂ (the filter coefficients of which are C ₁₁ (∧) to) having transfer characteristics from the corresponding speakers 15 ₁ and 15 ₂ to the microphones 16 ₁ and 16 _2. C ₂₂ (∧)) and digital filters 19 ₁₁ and 19 ₁₂ that calculate a cancellation signal from the reference signal x ₁ based on the filter coefficients W ₁₁ and W ₂₁ and digital filters 18 ₁₁₁ to 18 ₁₂₂ . Based on the signal x ₁ and the error signals e ₁ and e ₂ , the signal x ₁ , that is, the transfer characteristic from the noise source to the microphones 16 ₁ and 16 ₂ has the same amplitude and opposite phase (reverse transfer characteristic). So that the digital filters 19 ₁₁ and 19 ₁₂
MEFX LMS to update the filter coefficients W ₁₁ and W ₂₁ of
It comprises processing units 20 ₁₁ and 20 ₁₂ .

MEFX LMS processing units 20 ₁₁ and 20
₁₂ is MEFX (Multiple Err) as an adaptive algorithm.
or Filtered-X) LMS algorithm, and the reference signal x ₁ and error signals e ₁ and e ₂ filtered by the FIR filters 18 ₁₁₁ to 18 ₁₂₂ by the algorithm.
In order to generate the optimum cancellation signal from the above, the inverse transfer characteristic is calculated, and based on the calculation result, the adaptive filters 19 ₁₁ , 1
The control for updating the filter coefficients W ₁₁ and W ₂₁ of 9 ₁₂ is executed.

Further, the fixed filters 21 _{1 to} 21 ₈ are set in advance to experimentally measured values.

Similarly, the adaptive control circuit 12n (n =
2, 3, 4) are digital filters 18n _{11 to} 18n _22.
, Digital filters 19n ₁ and 19n ₂ and MEFX
It is composed of LMS processing units 20n ₁ and 20n ₂ (n = 2, 3, 4).

Next, even when the initial values of the digital filters 19 _{11 to} 19 ₄₂ are set to experimentally measured values in advance, instead of using the fixed filters 21 _{1 to} 21 ₈ together, the same effect as the above embodiment is obtained. Play.

[0036]

As described above, according to the present invention, a signal having a high correlation with the vibration from the vibration source is inputted as the reference signal, and the reference signal is filtered by using the adaptive filter to thereby cancel the cancellation signal. Control means for generating, canceling vibration generating means for generating a canceling signal based on the canceling signal generated by the controlling means, and canceling error between the canceling vibration generated by the canceling vibration generating means and the vibration from the vibration source An active vibration for controlling the vibration from the vibration source by controlling the canceling signal so that the power of the error signal detected by the error signal detecting means is minimized. In the control device,
The filter characteristic (filter coefficient value) for generating a predetermined canceling signal according to the vibration to be canceled is obtained in advance, and the obtained filter characteristic is set as the initial characteristic in the adaptive filter. A filter characteristic for generating a predetermined canceling signal corresponding to the filter characteristic is obtained in advance, and a characteristic time-invariant filter (fixed filter) in which the obtained filter characteristic is set is used together with the adaptive filter. There is an effect that it is possible to eliminate the vibration having the above and to shorten the convergence time until the cancellation signal that sufficiently cancels the vibration is generated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of an active vibration control device according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a second embodiment of the active vibration control device according to the present invention.

FIG. 3 is a block diagram showing a schematic configuration of a second embodiment of the active vibration control device according to the present invention.

FIG. 4 is a block diagram showing a schematic configuration of an application example in which the active vibration control device according to the present invention is applied to a road noise canceller.

[Description of Reference Signs] 1 reference signal sensor (vibration detection means) 2 adaptive filter (control means) 3 speaker (offset vibration generation means) 4 microphone (error signal detection means) 11 fixed filter

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuyasu Nakamura 1-4-1 Chuo, Wako-shi, Saitama, Honda R & D Co., Ltd. (72) Inventor Nozomi Saito 1-8 Nishigotanda, Shinagawa-ku, Tokyo No. Alpine Co., Ltd.

Claims (3)

[Claims] 1. A cancellation signal having a transfer characteristic having a phase opposite to that of a vibration transfer characteristic from the vibration source is generated by inputting a signal highly related to the vibration from the vibration source as a reference signal. Controlling means, a canceling vibration generating means for generating canceling vibration based on a canceling signal generated by the controlling means, and a canceling error between the canceling vibration generated by the canceling vibration generating means and the vibration from the vibration source. In an active vibration control device comprising an error signal detection means for detecting, the error signal detected by the error signal detection means controls the transfer characteristic of the cancellation signal so as to have a minimum value, as the value of the adaptive filter, A value for generating a cancellation signal having a predetermined vibration transfer characteristic according to the vibration to be canceled is previously obtained, and the obtained value is set as an initial value in the adaptive filter. The active vibration control system for. 2. The active vibration control device according to claim 1, wherein the initial value is a value suitable for canceling vibration generated during warm-up operation of the vehicle. 3. A cancellation signal having a transfer characteristic having a phase opposite to that of the vibration transfer characteristic from the vibration source is generated by inputting a signal highly related to the vibration from the vibration source as a reference signal. Controlling means, a canceling vibration generating means for generating canceling vibration based on a canceling signal generated by the controlling means, and a canceling error between the canceling vibration generated by the canceling vibration generating means and the vibration from the vibration source. An active vibration control device that includes an error signal detection unit for detecting and controls the transfer characteristic of the cancellation signal so that the error signal detected by the error signal detection unit has a minimum value. A filter value for generating a cancellation signal having a predetermined vibration transfer characteristic is obtained in advance, and a fixed filter in which the obtained filter value is set is used together with the adaptive filter. The active vibration control system.