JPH0511778A - Active vibration control device - Google Patents

Abstract

PURPOSE:To enable vibration control suitable for human feelings by changing the pseudo-inverse transmission characteristics by a control means so that the error signal may be minimized on the basis of the corrected error signal from a correcting means and the vibration transmission characteristics between the secondary vibration generating source and an error sensor. CONSTITUTION:The vibration of a generating source (A) is detected by means of a sensor (B) and supplied to a control means (C) as a reference signal (X). The signals generated by the pseudo-inverse transmission characteristics (H') of the same amplitude and the inverse phase relative to the transmission characteristics H2 of the noises or vibrations from the generating source (A) to an occupant is supplied to the secondary generating source (D), and the canceling vibration is generated. The canceling vibration is supplied to a correcting means (F) as an error signal epsilon through an error sensor (E), and the error signal epsilon is corrected to a signal epsilon' suitable for human feelings, and supplied to a control means (C). The control means (C) changes the pseudo-inverse transmission characteristics (H') so that the error signal epsilon may be minimized on the basis of the corrected error signal epsilon' from the correcting means (F) and the vibration characteristics H1 between the secondary generating source (D) and the error sensor (E), and supplies the canceling signal to the secondary generating source (D).

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 device, and more particularly to an active vibration control device for suppressing noise or vibration in a vehicle cabin or a cabin in which passengers of transportation means such as automobiles, airplanes and ships live. ..

[0002]

2. Description of the Related Art The term "vibration" used in the present invention means not only vibration in the original sense but also noise such as sound and noise.

Conventionally, as this type of active vibration control device, a noise source (vibration source), a first sensor for detecting noise from the noise source, and an output from the first sensor are used as reference signals. Adaptive control means for generating a signal having a transfer characteristic opposite to the noise transfer characteristic from the noise source to a human being based on the input reference signal, and cancellation for generating a canceling sound according to the output from the adaptive control means. And a second sensor for detecting an error between the noise from the noise source and the canceling sound from the canceling sound generating means, and the adaptive control means includes the second sensor.
There is proposed an active noise control device which controls so as to change the reverse transfer characteristic so as to minimize the error in accordance with an error signal from the sensor (for example, Japanese Patent Laid-Open No. 1-50).
1344).

[0004]

In the above proposed apparatus, the error signal detected by the second sensor is supplied to the adaptive control means without any correction. Therefore, as for the noise of the control target to be silenced (cancelled), basically, only the signal component in the frequency range with a large amplitude is canceled first among the components of the detected noise signal, and the component to be silenced originally is to be canceled out. When the signal amplitude is small, there is a case where the noise reduction capability for the noise component is low or the noise is not reduced at all.

As a result, the noise given to the occupant does not become the noise controlled so as to match the human sense of hearing, and the occupant may still feel uncomfortable, and efficient noise control is not performed. There was a problem.

Further, a vibration control device for suppressing the vibration of the original meaning may have the same structure as the above noise control device, but it is possible to similarly perform vibration control adapted to the human sensory characteristics. desirable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an active vibration control device capable of noise control and vibration control suitable for human sensation such as human hearing and body sensation.

[0008]

To achieve the above object, according to the present invention, a vibration source, a first sensor for detecting vibration from the vibration source, and a first sensor for detecting the vibration from the vibration source are provided. Control means for inputting an output as a reference signal, and based on the reference signal, generating a canceling signal having a transfer characteristic opposite to a vibration transfer characteristic from the vibration source to a human being, and a canceling vibration according to an output from the control means. And a second sensor for detecting an error between the vibration from the vibration source and the canceling vibration from the canceling vibration generating means, and the control means includes a second sensor. An active vibration control device for controlling to change the reverse transfer characteristic so as to minimize the error according to an error signal, and a correction for correcting the error signal so as to be suitable for human sense of hearing or bodily sensation. Characterized by having means Dynamic vibration control device is provided.

[0009]

By the correcting means, the error signal detected by the second sensor is corrected so as to match the human sense of hearing or the human sensation, so that the vibration control that matches the human sensitivity can be performed.

[0010]

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

First, FIG. 1 shows the basic construction of the apparatus of the present invention. The vibration from the vibration source A is detected by a sensor B including a microphone and an acceleration pickup, and is supplied as a reference signal x to a control means C including a digital filter and DFT (discrete Fourier transform). The control means C
Is a speaker, a vibration exciter or the like for generating a signal based on the reference signal x, which has a pseudo reverse transfer characteristic H ′ of the same amplitude and opposite phase to the transfer characteristic H ₂ of noise or vibration from the source A to the occupant. The secondary source D of noise or vibration is supplied, and the secondary source D generates a canceling vibration. This offset vibration is detected by an error sensor E such as a microphone or an acceleration pickup, and is supplied to the correction means F as an error signal ε.
The correction means F is composed of, for example, a filter, corrects the error signal ε into a signal ε'which is preferable for human hearing or sensation, and supplies it to the control means C. The control means C receives the correction error signal ε'from the correction means F, the secondary source D and the error sensor E.
Based on the vibration transfer characteristic H ₁ (Cij described later) between the two, the pseudo reverse transfer characteristic H ′ in the following equation is changed so that the error signal ε is minimized, and a cancellation signal is supplied to the secondary source D. ..

[0012]

[Number 1] epsilon = H ₂ x + H ₁ for H'x changing the correction error signal epsilon 'and the vibration transmission characteristic H ₁ and the inverse transfer characteristic H based on' later.

2 to 4 show an embodiment of the present invention,
In this embodiment, the active vibration control system of the present invention is applied to an engine noise canceling system of a vehicle. In this embodiment, as shown in FIGS. 3 and 4, four speakers 7 are used.
₁ -7 ₄ and four microphones 8 ₁ -8 ₄ is a configuration arranged two each pair in the vehicle compartment front and rear of the vehicle.

As shown in FIG. 2, a noise detecting sensor 2 including an acceleration pickup for detecting an ignition pulse of the engine 1 as a noise source (vibration source) and engine vibration is mounted on the vehicle body and detected by the sensor 2. The engine noise signal is input to the A / D converter 4 of the adaptive control circuit 3 as the control means, sampled by the A / D converter 4 and used as the reference signal x of the pulse train, the correction filter G as the correction means according to the present invention. is input to the ₁ -G _4.
In the correction filters G ₁ -G ₄ , the sound pressure level of the specific frequency of the reference signal x is attenuation-corrected, and the corrected reference signal is controlled by the control block
Input to _{1-3 4.} Based on the correction reference signal x (n), the control blocks 3 _{1 to} 3 ₄ have the same amplitude and opposite phase at the microphone position installed near the occupant with respect to the noise transfer characteristic H ₂ from the engine to the occupant. possible set transfer characteristic (pseudo inverse transfer characteristic) H _'1 ~H' _4, i.e., form a source of cancellation signal. Each control block 3 ₁ -3 ₄ 4 FI having a transfer characteristic between the speaker 7 and the microphone 8
The R filter FIRi (i = 1-16) and the pseudo reverse transfer characteristic H′i (i = 1−1) set for each control block.
4) adaptive digital filter ADFi (i = 1
-4) and a processing unit LMS having a built-in arithmetic unit based on the LMS algorithm. 16 by the FIR filter FIRi All control block 3 ₁ -3 ₄ (FIR1-FIR1
6) is provided, four loudspeakers 7 ₁ -7 ₄ and four microphones ₈₁ transfer characteristic between -8 ₄ different 16 each in the combination s corresponding different speaker and Mairokuhon C ₁ a-C _{4
a, C 1 b-C 4} b, C 1 c-C 4 c, respectively have a C ₁ d-C ₄ d. Further, as the algorithm of the processing unit LMS of the control block 3 ₁ -3 _4, for example, Haruo Hamada "Multi-Channel Active Noise Control and Its Applications" (1
The Multiple Error Filtered-X LMS algorithm disclosed in the Society of Automotive Engineers, Vibration and Noise Division Committee, March 22, 991) is used.

The cancellation signal from the control block 3 ₁ -3 ₄ D
/ In A converter 5 ₁ -5 ₄ is converted into an analog signal, and drives each speaker 7 ₁ -7 ₄ after being Zohaba by The amplifier 6 ₁ -6 _4, the speaker generates secondary noise.

[0016] Each microphone 8 ₁ -8 ₄ speaker 7 ₁ -
The secondary noise from 7 ₄ is received, and the received secondary noise signal is the corresponding A / D converter 9 ₁ as an error signal ε ₁ −ε _4.
-9 ₄ is sampled at, for pulse train error signal epsilon _1-epsilon
4 is input to the correction filter (G) 10 _{1-10 4} as the correction means according to the present invention. Correction filter 10 ₁
-10 ₄ attenuates and corrects the sound pressure level of the error signal ε ₁ -ε _{4 in} a specific frequency range, and outputs a correction signal ε ′ ₁ −ε ′ ₄ .
The correction signal epsilon _{'1-epsilon' 4} is supplied to the processing unit LMS of the control block 3 ₁ -3 _4. Each processing unit LMS has four transfer error signals ε'i (i = 1-4) and four transfer characteristics Cij (i = 1-4, i-4) corresponding to the combination of the corresponding speaker 8 and mylophone 10. The inverse transfer characteristic H′i (i = 1-4) of the filter ADF is changed so that each corresponding error signal εi (i = 1-4) is minimized in accordance with j = ad.

Correction filter G ₁ -G ₄ , 10 ₁ -10 ₄
Can be configured by an FIR filter similar to the FIR filter of the adaptive control circuit 3.

Next, the correction error signal ε'i and the transfer characteristic Ci
The method of changing the inverse transfer characteristic H′i of the filter ADF for minimizing the error signal εi according to j is performed as follows.

First, the symbols used in the equation 2-11 described below are defined as follows.

N: nth sample of quantized signal L: number of error sensors (4 in this embodiment) M: number of actuators (speakers) (4 in this embodiment) J: order of FIR filter K: Order of correction FIR filter εl (n): lth error sensor signal dl (n): noise signal component detected by lth error sensor x (n): reference signal Um (n): mth actuator signal H ' mi (n): i-th coefficient in the n-th sample of the m-th ADF filter Clmj: j-th coefficient of the J-th FIR filter representing the transfer characteristic between the m-th actuator and the l-th error sensor Gk: K-th correction FIR filter Coefficient of ε′l (n): corrected 1st error sensor signal μ: convergence coefficient mth actuator signal Um (n) is the reference signal x
(N) and the transfer characteristic H'mi (n) of the ADF filter are obtained by the following equation.

[0021]

[Equation 2] The l-th error signal εl (n) is the actuator signal Um (n) and the noise signal component d detected by the error sensor.
l (n) and the transfer characteristic Clmj of the FIR filter are obtained by the following equation.

[0022]

[Equation 3] The following equation is established from the equations 2 and 3.

[0023]

[Equation 4] On the other hand, the correction error signal ε′l (n) is expressed by the following equation.

[0024]

[Equation 5] Let J be the cost function, which is the sum of the root mean square outputs from the L error sensors,

[0025]

[Equation 6] Is represented.

The gradient is expressed by the following equation.

[0027]

[Equation 7]

[0028]

[Equation 8] here,

[0029]

[Equation 9]

[0030]

[Equation 10] Substituting equation 8 into equation 7,

[0031]

[Equation 11] Therefore, the coefficient update formula of the ADF filter is as follows.

Each of the correction filters G ₁ -G ₄ , 10 ₁ -10 ₄ has a coefficient of the filtering characteristic as shown in FIG. 5, for example, and according to this, the noise of the engine 1 as shown in FIG. Of the frequency components, it is perceived as being noisy, for example, 250
In order to effectively muffle the frequency components near Hz, the A characteristic filter is used to convert the frequency components to those shown in FIG. As a result, the low frequency range (in this case, around 100 Hz) is silenced at a relatively large rate as shown in FIG. 8, while the sound deadening effect is less in the middle frequency range (in this case, around 250 Hz). In contrast, in this embodiment,
As shown in FIG. 9, a large silencing effect can be obtained in the middle frequency range and above. As a result, it is possible to give the occupant a feeling of muffling effect which is preferable for hearing.

FIG. 10 is a block diagram showing another embodiment of the active vibration control apparatus of the present invention, the configuration of FIG. 2 described above in this embodiment, excitation instead of the speaker 7 ₁ -7 ₄ the vessel 7 _'1 -7' _4, only in that instead of the microphone 8 ₁ -8 ₄ are the accelerometer 8 _'1 -8' ₄ each use and are different. In FIG. 10, elements corresponding to those in FIG. 2 are designated by the same reference numerals.

In the case of this embodiment, the filter characteristic of each correction filter 9 has a filtering characteristic as shown in FIG. 11. According to this, among the frequency components of the vibration of the engine 1 as shown in FIG. It has a filter characteristic that efficiently attenuates only a component of a specific frequency, for example, 7 Hz that gives a discomfort when the vehicle seat is seated (FIG. 13). As a result, as shown in FIG. 14, the 7 Hz component in the frequency component of the vibration is attenuated, and the occupant can be provided with the feeling of the vibration suppressing effect that is preferable for the sensation.

[0035]

As described above, according to the present invention,
A vibration source, a first sensor that detects vibration from the vibration source, and an output from the first sensor as a reference signal, and based on the reference signal, a vibration transfer characteristic from the vibration source to a person. Control means for generating a canceling signal having a transfer characteristic opposite to that of the above, canceling vibration generating means for generating canceling vibration according to the output from the controlling means, vibration from the vibration source and canceling from the canceling vibration generating means A second sensor that detects an error from vibration, and the control means controls the reverse transfer characteristic so as to minimize the error in accordance with an error signal from the second sensor. The active vibration control device is characterized in that it has a correction means for correcting the error signal so as to match the human body sensation. It will be possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of an active vibration control device of the present invention.

FIG. 3 is a schematic side view showing the arrangement of a microphone and a speaker in a vehicle compartment of a vehicle.

FIG. 4 is a schematic top view of the same.

5 is a graph showing the filter characteristics of the correction filter of the embodiment of FIG.

FIG. 6 is a graph showing an example of frequency versus sound pressure level characteristics of vehicle interior noise.

7 is a graph showing an example of frequency versus sound pressure level characteristics of the error signal after correction according to the embodiment of FIG.

FIG. 8 is a graph showing frequency vs. sound pressure level characteristics of a conventional device before and after muffling.

9 is a graph similar to FIG. 8 showing the effect of the correction of the embodiment of FIG.

FIG. 10 is a configuration diagram showing another embodiment of the vibration control device of the present invention.

11 is a graph showing the filter characteristics of the correction filter of the embodiment of FIG.

FIG. 12 is a graph showing an example of frequency vs. vibration level characteristics of vehicle interior vibration.

13 is a graph showing an example of frequency-vibration level characteristics of the error signal after correction according to the embodiment of FIG.

14 is a graph showing an example of frequency versus vibration level before and after damping according to the embodiment of FIG.

[Explanation of symbols]

1 engine 2 accelerometer (first sensor) 3 adaptive control circuit (control means) 7 ₁ -7 ₄ speakers (canceling vibration generating source) 8 ₁ -8 ₄ microphones (second sensor) 10 ₁ -10 ₄ correction filter (correction means) 7 _'1 -7' ₄ vibrator (canceling vibration source) 8 _'1 -8' ₄ accelerometer (second sensor) G ₁ -G ₄ correction filter (correction means)

Claims (1)

Claim: What is claimed is: 1. A vibration source, a first sensor for detecting vibration from the vibration source, and an output from the first sensor as a reference signal, which is input based on the reference signal. A control means for generating a canceling signal having a transfer characteristic opposite to the transfer characteristic of vibration from the vibration source to the human being; a canceling vibration generating means for generating canceling vibration according to an output from the control means; And a second sensor for detecting an error between the vibration of the canceling vibration and the canceling vibration from the canceling vibration generating means, and the control means includes the second sensor.
An active vibration control device for controlling the reverse transfer characteristic so as to minimize the error in accordance with the error signal from the sensor, and the error signal is adapted to human hearing or body sensation. An active vibration control device having a correction means for correcting the above.