JP3471369B2 - Active vibration control device - 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 vibration control device, and more particularly to an active vibration control device for suppressing vibration in a vehicle cabin or a cabin in which an occupant of a transportation system such as an automobile, an aircraft or a ship lives.

[0002]

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

Conventionally, as an active vibration control device of this type, a first sensor for detecting a vibration from a vibration source and an output from the first sensor are input as a reference signal, and based on the reference signal. From the vibration source, an adaptive control means for generating a signal having a transmission characteristic opposite to the vibration transmission characteristic from the vibration source to the human being, a canceling sound generating means for generating a canceling sound according to an output from the adaptive control means, A second sensor for detecting an error between the vibration of the noise and the canceling sound from the canceling sound generating means, and the adaptive control means minimizes the error according to the error signal from the second sensor. Japanese Patent Laid-Open Publication No. 1-501344 discloses an active vibration control device that controls so as to change the reverse transfer characteristic.

In the proposed device, the error signal detected by the second sensor is supplied to the adaptive control means without any correction. Therefore, silence (offset)
As for the vibration (noise) to be controlled, basically, of the detected vibration signal components, only the signal component in the frequency range with a large amplitude is canceled first, and the signal amplitude of the component to be silenced is If it is small, the silencing ability for the noise component may be low or may not be siled at all.

FIG. 4 shows the frequency analysis result of the output of the second sensor. For example, as shown in the figure, a vibration peak P ₃ having a higher vibration level than the vibration peaks P ₁ and P ₂
In the above conventional apparatus, in order to suppress the vibration peaks P ₁ and P ₂ of interest, a signal having a high correlation with this vibration is used as a reference signal when the component of , The second peak acts to minimize the maximum value of the detection signal, so that the vibration peaks P ₁ and P ₂ are
It will be masked to _3, resulting in uncontrolled vibration peak P _1, P _2.

When the vibration peaks P ₁ and P ₂ are low frequencies that give an occupant an unpleasant feeling, the low frequency noise in the vibration components transmitted from the vibration source to the occupant cannot be suppressed, so that low frequency noise is generated. May make passengers uncomfortable.

[0007]

As described above, in the conventional device, the component of the sound to be silenced is not always silenced, and the passenger may still feel uncomfortable. Therefore, efficient vibration control is possible. However, there was a problem that noise control was not performed.

Therefore, an object of the present invention is to provide an active vibration control device which enables vibration control and noise control by positively extracting only the vibration component to be suppressed or eliminated.

[0009]

In order to achieve the above object, the present invention inputs a first sensor for detecting a vibration from a vibration source and an output from the first sensor as a reference signal, control means for generating a cancellation signal of the inverse of the transfer characteristic and the vibration transmission characteristics from the vibration source based on the signal to humans, and canceling the vibration generating means for generating a canceling vibration in response to an output from the control means, An active vibration control device comprising a second sensor for detecting an error between a vibration from the vibration source and a canceling vibration from the canceling vibration generating means, wherein an internal control of an error signal from the second sensor is provided. It has a 1st filter which passes only a frequency component of object, and the above-mentioned control means is from the above-mentioned cancellation signal generating means to the above-mentioned 2nd sensor.
A second filter having a transfer characteristic and a position of the reference signal
A third filter for adjusting the phase, and the first filter
Filter output signal and the output of the third filter
By the signal corrected by the filter of 2
An adaptive filter that is updated,
The above-mentioned cancellation by adjusting with an adaptive filter
It is characterized by generating an issue .

[0010]

The control means outputs the output signal of the frequency component to be controlled which has passed through the filter among the error signals of the vibration signal from the vibration source detected by the second sensor and the canceling vibration signal from the canceling vibration generating means. Accordingly, the reverse transfer characteristic is changed so that the error is minimized.

[0011]

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

FIG. 1 is a block diagram in which an active vibration control system according to an embodiment of the present invention is applied to a vehicle engine noise control system. In this embodiment, a vibration detecting sensor 2 as a first sensor including an acceleration pickup that detects an ignition pulse and engine vibration of an engine 1 which is a vibration source, and a detection signal x of the sensor 2 are indicated by a dotted line in FIG. As shown, an arbitrary order generator 1 that outputs a sampling signal x ₂ that samples the fundamental frequency component (f ₁ ) and the second and subsequent frequency components (f ₂ , ...).
The adaptive control circuit 3 including one and a plurality of control blocks 3 _{1 to} 3 ₄ and a plurality (4 in this example, 4) as a canceling vibration generating means.
Individual) speakers 7 _{1 to} 7 ₄ , as a second sensor for detecting vibrations (sounds) from the engine 1 and vibrations (sounds) from the speakers 7 _{1 to} 7 ₄ as error signals ε _{1 to} ε ₄ . A plurality (four in this example) of microphones 8 ₁ to 8 ₄ and extraction error signals ε ′ _{1 to} ε ′ ₄ obtained by extracting only the frequency components to be controlled among the detection signals from the microphones 8 ₁ to 8 ₄ This is a configuration having a plurality of (four in this example) order component extraction tracking filters 10 ₁ to 10 ₄ . Again 4
The two loudspeakers 7 _{1 to} 7 ₄ and the four microphones 8 ₁ to 8 ₄ are arranged in pairs in the front and rear portions of the vehicle compartment of the vehicle. Adaptive control circuit 3, depending on the tracking filter 10 ₁ to 10 ₄ of the output signal ε _'1 ~ε' _4, inverse of the transfer characteristic (pseudo inverse transfer characteristic with respect to the transfer characteristic of H ₂ vibrations from the engine 1 to the occupant ) H'is added to the canceling signals output to the speakers 7 _{1 to} 7 ₄ to cancel the vibration (noise) of the frequency component that makes the occupant uncomfortable among the vibration components transmitted from the engine 1 to the occupant, The pseudo reverse transfer characteristic H'provided by the adaptive control circuit 3 is changed by the following mathematical expression so that the error signal ε is minimized. Here, H ₁ is a vibration transfer characteristic between the speakers 7 _{1 to} 7 ₄ and the microphones 8 ₁ to 8 ₄ .

Ε = H ₂ x + H ₁ H'x The number of speakers 7, microphones 8 and tracking filters 10 to be used is appropriately determined according to the number of pseudo reverse transfer characteristics H'used in the calculation of the adaptive control circuit 3. By doing so, efficient vibration control and noise control become possible.

As shown in the figure, the adaptive control circuit 3 of the engine noise control apparatus samples the vibration signal of the engine 1 detected by the vibration detection sensor 2 and outputs a pulse train reference signal (reference signal) x (reference signal). n) the A / D converter 4, the arbitrary order generator 11, and the vibration transmission characteristic H ₂ from the engine 1 to the occupant based on the sampling signal x ₂ output from the arbitrary order generator 11. The transfer characteristic (pseudo reverse transfer characteristic) H'set to have the same amplitude and opposite phase at the position of the microphone installed near the occupant.
Control blocks 3 _{1 to} 3 ₄ for generating cancellation signals _{1 to} H ′ ₄ .

Each of the control blocks 3 _{1 to} 3 ₄ has four tracking filters 12 _{1 to} 12 ₄ for phase adjustment, and four F having transfer characteristics between the speaker 7 and the microphone 8.
The IR filter FIRi (i = 1 to 16) and the pseudo reverse transfer characteristic H′i (i = 1 to 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. The tracking filters 12 _{1 to} 12 ₄ for phase adjustment are provided in the respective control blocks 3 _{1 to} 3 ₄ so as to correspond to the phase delay of the tracking filters 10 ₁ to 10 ₄ for extracting the next component.

A total of 16 control blocks 3 _{1 to} 3 ₄ (FIR ₁ to FIR 16) are provided for the FIR filters FIRi, and four speakers 7 _{1 to} 7 ₄ and four microphones 8 are provided.
Transfer characteristics C ₁ a to C ₄ a, C ₁ between different speakers and microphones corresponding to 16 different combinations ₁ to 8 ₄ respectively.
_{b~C 4 b, C 1 c~C 4} c, respectively have a C ₁ d~C ₄ d. Further, for example, as an algorithm of the processing unit LMS of the control block 3 ₁ ~3 _4, SJElliott, "A Multiple by PANelson like Error LMS Algorithm and ItsApplic
ation to the Active Control of Sound and Vibratio
n ”(IEEE Transactions, ASSP-35, NO.10 October 198
The Multiple Error Filtered-X LMS algorithm disclosed in 7) is used.

The cancellation signal from the control block 3 ₁ to 3 _4,
D / A converters 5 _{1 to} 5 ₄ convert into analog signals,
After being amplified by the amplifiers 6 _{1 to} 6 ₄ , the speakers 7 _{1 to} 7 ₄ are driven, and the speakers 7 _{1 to} 7 ₄ generate secondary vibration (cancellation vibration).

Each of the microphones 8 ₁ to 8 ₄ is a speaker 7 _1
7-4 receives the canceling vibration from the received offset oscillating signal is sampled by the A / D converter 9 _to 93 ₄ corresponding as an error signal ε ₁ ~ε _4, the pulse train error signal epsilon ₁
~ε are to be inputted to the tracking filters 10 ₁ to 10 ₄ for order component extracted according to the present invention as a _4.
Error signal is input to the tracking filter 10 ₁ ~10 ₄ ε ₁ ~ε ₄ is any frequency component based on an external control signal by the tracking filter 10 ₁ to 10 ₄ (extraction error signal ε'i (i = 1 4 to 4)) are extracted, and in this example, only the fundamental frequency component (f ₁ ) and the secondary frequency component (f ₂ ) are extracted and input to the processing unit LMS. There is.

Each processing unit LMS has four transfer error characteristics ε′i (i = 1 to 4) and four transfer characteristics Cij corresponding to the combination of the corresponding speaker 8 and microphone 10.
According to (i = 1 to 4, j = a to d), the filter A so that each corresponding error signal εi (i = 1 to 4) is minimized.
The reverse transfer characteristic H'i (i = 1 to 4) of the DF is changed. The processing unit LMS is adapted to obtain the inverse transfer characteristic H′i of the filter ADF for minimizing the error signal εi according to the extracted error signal ε′i and the transfer characteristic Cij.

Next, the operation of the apparatus of this embodiment will be described.

The engine vibration signal x detected by the vibration detection sensor 2 is input to the A / D converter 4 of the adaptive control circuit 3 and is sampled by the A / D converter 4 and a reference signal (reference signal) x of a pulse train is output. It is input to the arbitrary order generator 11 as (n). Arbitrary order generator 1
1 is a sampling signal obtained by sampling the input standard signal (reference signal) x (n) into the fundamental frequency component (f ₁ ) and the second and subsequent frequency components (f ₂ , ...) Shown by the dotted line in FIG. x ₂ is output to each of the control blocks 3 _{1 to} 3 ₄ and the sampling signal x ₂ is also output to the tracking filters 10 ₁ and 10 ₂ .
The control blocks 3 _{1 to} 3 ₄ generate the canceling signals of the transfer characteristics (pseudo reverse transfer characteristics) H ′ _{1 to} H ′ ₄ as described above based on the sampling signal x ₂ . The cancellation signals from the respective control blocks 3 _{1 to} 3 ₄ are converted into analog signals by the respective D / A converters 5 _{1 to} 5 ₄ and further amplified by the respective amplifiers 6 _{1 to} 6 ₄ , and then the respective speakers 7 ₁ to 7 ₄ is driven, and the speakers 7 _{1 to} 7 ₄ generate canceling vibrations. The microphones 8 ₁ to 8 ₄ detect the canceling vibrations from the speakers 7 _{1 to} 7 ₄ and the vibration directly propagated from the engine 1. The canceling vibration signal detected by the microphones 8 ₁ to 8 ₄ and the vibration signal from the engine 1 are input to the corresponding A / D converters 9 _{1 to} 9 ₄ . The signals input to the A / D converters 9 _{1 to} 9 ₄ are supplied to the A / D converter 9
The error signal ε _{1 of the} pulse train sampled from _{1 to} 9 ₄
Extracted as ~ε _4, the tracking filter 10 ₁ -
Is input to the 10 _4.

From these error signals ε _{1 to} ε ₄ , only the fundamental frequency component (f ₁ ) and the secondary frequency component (f ₂ ) to be controlled are extracted by the tracking filters 14 _{1 to} 14 _{4 as} shown in FIG. The error signals ε ′ _{1 to} ε ′ ₄ are extracted and supplied to the processing units LMS of the respective control blocks 3 _{1 to} 3 ₄ . Each processing unit LMS is a combination of the four extraction error signals ε ′ _{1 to} ε ′ ₄ and the speaker 7 and the error detection microphone 8.
According to the six transfer characteristics Cij (i = 1 to 4, j = a to d), the corresponding error signals ε _{1 to} ε ₄ are minimized.
Inverse transfer characteristic of the filter ADF1~ADF4 H _'1 ~H' ₄
To change.

As a result, for example, the frequency analysis result of the noise generated from the engine 1 is as shown by the solid line in FIG.
Even if the noise level of the highest low frequency noise peaks S ₁ which is the control object from the noise peak S _3, S ₂ is low, it is possible to mute the noise peaks S _1, S ₂ of the low frequency as indicated by a solid line in FIG. , You can mute only the noise you want to control.

[0024]

As described above, according to the invention of claim 1, the first sensor for detecting the vibration from the vibration source,
Receives an output from the first sensor as a reference signal, and control means for generating a cancellation signal of the inverse of the transfer characteristic and the vibration transmission characteristics from the vibration source based on the reference signal to a human, said control means Vibration control including a canceling vibration generating means for generating a canceling vibration according to an output from the second sensor, 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. A device, wherein the second
Has a first filter which passes only frequency components of the internal control target of the error signal from the sensor, said control means,
Transmission from the canceling signal generating means to the second sensor
A second filter having characteristics and a phase adjustment of the reference signal
A third filter for adjusting, and the first filter
Of the output signal of the third filter and the output of the third filter
Coefficients are updated sequentially with the signal corrected by the filter
And an adaptive filter that controls the reference signal.
The cancellation signal can be adjusted by adjusting with a adaptive filter.
Since it is characterized in that it is generated , it is possible to provide an active vibration control device capable of accurately controlling only the vibration component to be suppressed or eliminated.

Further, according to the invention described in claim 2, in addition to the effect described in claim 1, since the frequency to be controlled can be arbitrarily selected, vibration control and noise control can be more efficiently performed.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an operation of the apparatus shown in FIG.

FIG. 3 is a diagram showing an operation of the apparatus shown in FIG.

FIG. 4 is a diagram showing an example of a frequency analysis result of an output of a second sensor.

[Explanation of symbols]

2 Microphone for vibration detection (first sensor) 3 Adaptive control circuit (control means) 7 speaker (means for canceling vibration) 8 Error detection microphone (second sensor) 10 Tracking filter 11 Arbitrary order generator

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-306845 (JP, A) JP-A-1-314500 (JP, A) JP-A-5-11778 (JP, A) JP-A-4- 359297 (JP, A) JP 5-111770 (JP, A) JP 5-289679 (JP, A) JP 5-313672 (JP, A) JP 6-130968 (JP, A) JP-A-6-161464 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G10K 11/178 B60R 11/02 F01N 1/00

Claims (2)

(57) [Claims] 1. A first sensor for detecting vibration from a vibration source, and an output from the first sensor as a reference signal, and a vibration transfer characteristic from the vibration source to a human being based on the reference signal. control means for generating a cancellation signal of the inverse of the transfer characteristic from the canceling vibration generating means for generating a canceling vibration in response to an output from the control means, from the vibration and the canceling vibration generating means from the vibration source An active vibration control device comprising a second sensor for detecting an error with respect to a canceling vibration, comprising a first filter for passing only a frequency component to be controlled in an error signal from the second sensor. However, the control means controls the canceling signal generating means from the second
A second filter having a transfer characteristic to the sensor;
A third filter for adjusting the phase of the reference signal,
The output signal of the first filter and the output signal of the third filter
With the output signal corrected by the second filter
And an adaptive filter whose coefficient is updated sequentially,
By adjusting the illumination signal by the adaptive filter
An active vibration control device characterized by generating the cancellation signal . Wherein said first filter and said third Fi <br/> filter is active vibration control system of <br/> claim 1, characterized in that the tracking filter.