JP3280462B2 - Vehicle 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 a vibration control device for a vehicle in which vibration, that is, noise of the vehicle is reduced by an interference effect using vibration for reduction.

[0002]

2. Description of the Related Art In a vehicle, in particular, an automobile or the like in which noise caused by an engine, that is, first vibration is a problem, a reducing vibration, that is, second vibration is generated from a speaker or the like, and the first vibration and second vibration are generated. It has been proposed to reduce the first vibration by interference with the first vibration. In this type of vibration reduction device, as shown in Japanese Patent Application Publication No. 1-501344, a reference signal generator that extracts a signal from a vibration source, that is, a signal corresponding to the first vibration, as a reference signal, A microphone that picks up vibration in a predetermined space where noise due to vibration is a problem, a speaker that generates a second vibration toward the predetermined space, and an adaptive type that generates the second vibration output from the speaker A digital filter; and an algorithm operation device for sequentially optimizing filter coefficients of the filter. That is, the adaptive digital filter adjusts the gain, phase, and the like of the reference signal according to the reference signal to generate the second vibration, while reducing the filter coefficient of the adaptive digital filter so that the vibration detected by the microphone is reduced. Are sequentially optimized by the algorithm operation device. In general, a least-squares method is used as an algorithm for optimization.

[0003]

When performing the above-described vibration reduction utilizing interference, as a speaker for outputting a vibration for reduction, a speaker for audio generally mounted on a vehicle is used. It is conceivable to use mosquitoes. As described above, it has been found that when the speaker is used for both vibration reduction and audio, depending on the situation, there are cases where the vibration is reduced well and cases where it is not.

In pursuit of the cause of such a problem, a change in speaker output due to a change in volume or sound quality due to an audio operation affects an impulse response between a speaker and a microphone, that is, a transfer characteristic. Was given. That is, in the optimization method for forming the vibration for reduction, the impulse response between the speaker and the microphone is set in advance, but the speaker output is changed by the audio operation. In some cases, the impulse response deviates significantly from the set conditions, and in such a case, the vibration cannot be reduced satisfactorily.

[0005] Therefore, an object of the present invention is to always provide good vibration even when the speaker is used for both vibration reduction and audio, regardless of a change in the speaker output due to the audio operation. An object of the present invention is to provide a vehicle vibration control device capable of reducing the vibration.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention has the following configuration. That is, a vehicle vibration control device for a vehicle in which an audio signal from an audio unit is amplified by an amplifier having a sound quality adjustment circuit and a gain adjustment circuit and output from a speaker provided in a vehicle cabin. Output means for outputting a reduction vibration from the speaker to the vehicle interior through an amplifier for use in the vehicle, a microphone for detecting the vibration in the vehicle interior, and the speaker and the microphone so that the vibration detected by the microphone is reduced. Optimizing means for optimizing the vibration for reduction while considering the impulse response between, and when an operation for adjusting the sound quality or gain of the amplifier is performed, the operation of the impulse response is performed according to the content of the operation. And characteristic changing means for changing the control characteristic for the optimization.

The optimizing means includes a converting means for converting a transfer function between the microphone and the speaker into an impulse response when optimizing the reducing vibration. It can be configured as changing characteristics.

The optimizing means is set so as to optimize the vibration for reduction based on a product of an impulse response between the microphone and the speaker and a predetermined convergence coefficient, and the characteristic changing means is provided. However, only the convergence coefficient of the convergence coefficient and the impulse response may be changed.

An amplifier for the microphone and an amplifier for the speaker are provided, and the characteristics of both the amplifiers are set as the impulse response so as to be related to the optimization of the reducing vibration, and the characteristic changing means is provided. The characteristics of the microphone amplifier can be changed.

[0010]

According to the present invention, the speaker output is changed due to the audio operation while the cost is reduced by using the speaker for both vibration reduction and audio. In this case, the control characteristics related to the impulse response can be corrected according to the change of the speaker output, so that the vibration can always be reduced satisfactorily.

By adopting the constitution as described in claims 2 and 3, the effect described in claim 1 can be obtained by a method which can be easily adopted in practical use, which is preferable in practical use. .

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. In FIG. 1, an automobile 1 is a four-seater passenger car having a driver's seat 3, a passenger seat 4, and left and right rear seats 5 and 6 in a cabin 2. An in-line four-cylinder gasoline engine 8 is mounted on an engine room 7 formed at the front of the vehicle body, and its ignition coil is indicated by reference numeral 9.

The engine 8 is a noise source that generates a periodic vibration according to the engine speed, that is, a first vibration source. The cabin 2 is a predetermined space in which vibration of the engine 8 should be reduced. For this purpose, five speakers 11 and eight microphones 12 are installed in the cabin 2 as a predetermined space. The speaker 11 is a second vibration source that generates a second vibration for reducing engine noise in the vehicle compartment, and the microphone 12 is a vibration detecting unit that detects actual vibration of the vehicle compartment. As is known, the instrument panel includes, for example, an audio source comprising a combination of a tuner, a cassette deck, and a CD deck.
A source 31 is provided.

The vehicle 1 has a control unit U mounted thereon using a microcomputer. The input / output relationship for the control unit U is shown in FIG.
The control unit U has a control unit 20 including a CPU. The control unit 20 receives a signal from the primary coil of the ignition coil 9, that is, an ignition pulse signal corresponding to the engine speed via a waveform shaping circuit 21 and a cycle calculation circuit 22, and receives a signal from each microphone 12. , An amplifier 23, a low-pass filter 24, and an A / D converter 25. The output signal from the control unit 20 is D
The signal is output to the speaker 11 via the / A converter 26, the low-pass filter 27, and the amplifier 28.

The control unit 20 optimizes the second vibration as the reduction vibration to be output from the speaker 11 so that the vibration detected by the microphone 12 is reduced. Hereinafter, generation of the second vibration by the control unit 20 will be described.
The basic part of the generation of the second vibration will be described, and then the relationship with audio will be described.

In the embodiment, the second vibration is for reducing the periodic rotational vibration of the engine 8, for example, the secondary rotational component, and the second vibration is generated for one period of the periodic vibration of the engine 8. Thus, the amount of calculation for optimizing the second vibration is reduced, and the load on the control system is reduced as much as possible. Of course, the generation of the second vibration can be performed by a known appropriate optimization method, and the present invention is not limited to a specific optimization method.

Generation of Second Vibration (Basic) FIG. 3 is a block diagram showing the control unit 20.
For simplicity of description, the case where one speaker 11 and one microphone 12 are used is shown.

The control unit 20 adjusts the cycle of the vector y of the speaker input signal y to be output to the speaker 11 based on the result input from the cycle measuring circuit 22 (step 1,
The following step is abbreviated as S), and a built-in processor converts the matrix h of the impulse response h which is the transfer characteristic between the microphone 12 and the speaker 2 into a time series h (S).
2).

Next, the control unit 20 uses a processor to sequentially optimize the vector y based on the time series h of the impulse response h and the microphone output signal e input from the microphone 12 (S
3) After that, the vector y is converted into a time series y to be a speaker input signal y (S4) and output to the speaker 11.

The speaker 11 receives the input signal y
Is reproduced as anti-noise Z. On the other hand, the microphone 12
The noise d and the anti-noise Z cancel each other out, and the noise whose vibration energy is reduced is detected, and the result is output as a digital microphone output signal e to a processor built in the control unit 20. Hereinafter, the processor again executes the above step 3
And step 4 are repeated to obtain the speaker input signal y
Are sequentially optimized, and the vector y of the speaker input signal y is set so that the value of the microphone output signal e finally becomes zero.

Next, the calculation of the algorithm of the above steps performed by the control unit 20 will be described below.

First, the sampling period of the microphone output signal e of the microphone 12 by the control unit 20 is set to Δt. Assuming that the impulse response h, which is the transfer characteristic between the microphone 12 and the speaker 11, converges to 0 within a finite time J △ t, and the value of the impulse response h after the elapse of j △ t after the impulse input is given Let h _j be the noise d, which is the first vibration generated from the engine 8, the anti-noise Z, which is the second vibration generated from the speaker 11 when the speaker input signal y is given, and the noise d at that time. The relationship between the k-th sample value e (k) of the microphone output signal e at time k can be expressed by the following equation (1).

E (k) = d (k) + Z (k) = d (k) + matrix h ^T · matrix y (k) (1) where matrix h = [h ₀ h ₁ h ₂ ... H _J-1 ] ^T matrix y (k) = [y (k) y (k-1) y (k-2)... Y (k-J + 1)] ^T d ( k): component of noise d included in e (k) Z (k): component of anti-noise Z included in e (k) y (k): k-th sample of speaker input signal y Therefore, Z (k) in the equation (1) is expressed by the following equation (2).

[0024]

(Equation 1)

Since the noise d is a periodic noise having a certain period N △ t, the anti-noise Z and the speaker input signal y for reducing the vibration energy of the noise d have the same period as the noise d. It must be a periodic oscillation and a periodic signal with N △ t.

Therefore, the following equation (3) holds for the speaker input signal y. y (k) = y (K-qN) = y (k) y (k-1) = y (k-qN-1) = y (k + N-1) y (k-2) = y (k -qN-2) = y (k + N-2) (3) ... y (k-N + 1) = y (k- (q + 1) N + 1) = y (k + 1) where q = 0, 1, 2,... Therefore, equation (1) is expressed as follows: e (k) = d (k) + vector h ^T · time series y (k ) (4) where y (k) = [y (K) y (K + N-1) y (K + N-2) ... y (K + 1)] ^T

[0027]

(Equation 2)

Note that Q is the minimum value of the integer q satisfying J ≦ (q + 1) N.

Next, the K + i-th sample value e of the microphone output signal e at the time k + i at which the time i has further elapsed from the time k.
(K + i) (where i = 1, 2,...) Is given by the following equation (5)
Can be represented by

E (k + i) = d (k + i) + vector h ^T · time series y (k + i) = d (k + i) + time series h (i) ^T · time series y (k ) ..... (5) where the time series y (k + i) = [ y (k + i) 'y (k + i' -1) y (k + N-1) y (k + N -2) ············· y (k + i ^' +1)] ^T time series h (i) = [bar h _i ^' bar h _{i + 1} ^' _··· bar h _{N + 1} Bar h ₀ bar h ₁ ... Bar h _i ^' _-1 ] ^T i' is an integer remainder when i is divided by N.

By the way, in the equation (5), k merely represents an arbitrary initial point of the microphone input signal e. Therefore, when k = 0 and i is replaced with k again, the following equation (6) is obtained.

E (k) = d (k) + time series h (k) ^T · time series y (0) = d (k) + time series h (k) ^T · vector y where vector y = [y (0) y (N-1) y (N-2)... Y (1)] ^T = [y ₀ y _N-1 y _N-2 ... Y ₁ ] ^T where the next evaluation Introduce a function. F = E [e (k) ² ] = E [d (k) + time series h (k) ^T · vector y] = E [d (k) ² ] +2 vectors y ^T · E [d (k) · when the series h (k)] + vector y ^T · E [time series h (k) · time series h (k) ^T] vector y ······ (7) However, E [] is the expected value (E is an expected operator). From equation (7), the vector y of this evaluation function
Is given by the following equation (8). ∂F / ∂ vector y = 2E [d (k) · time series h (k)] + 2E [time series h (k) · time series h (k) ^T ] vector y = 2E [time series h (k) { d (k) + time series h (k) ^T vector y｝] = 2E [time series h (k) · e (k)] (8) where E [time series h (k) If the time series h (k) · e (K) is used as the instantaneous estimated value of [e (K)], the speed having the period N △ t (ie, the number of elements N) that gives the minimum value of F is obtained. The value of the vector y, which is the output signal vector, can be optimized by repeatedly calculating the following recurrence formula (9) based on the steepest descent method.

Vector y (K + 1) = Vector y (k) −μ · e (k) · Time Series h (k) (9) where μ / 2 is a convergence coefficient.

The recurrence formula (9) obtained in this manner corrects the setting of the vibration energy of the anti-noise for reducing the vibration energy of the noise by the processor as the data processing device built in the control unit 20. In this case, it is replaced with a simpler algorithm as shown below.

First, a pair of speaker 11 and microphone 1
When 2 is used, recurrence equation (9) is replaced by the following equation (10). y _{(k−j + QN)} ^′ (k + 1) = y _{(k−j + QN)} ^′ · (k) −μ · e (k) · h _j (10) At this time, the processor In k, for example, the following four operation procedures are performed.

Operation 1: Output the speaker input signal y _k ^′ (k) to the speaker 11 Operation 2: Input the microphone output signal e (K) from the microphone 12 Operation 3: Period measurement circuit 22 22 input from
N is the integer value closest to the value obtained by multiplying the rotation cycle of Ord / △ t or 1 / (Ord · △ t). Operation 4: j = 0, 1, 2,..., J-1 The recurrence formula (10) is calculated, where k ′ and (k−j + QN) ′ are k (k−k−
j + QN) is an integer remainder when N is divided by N, and Ord is an arbitrary constant for setting the lowest order of the noise to be reduced with respect to the engine speed.

Next, when a plurality of speakers 11... And microphones 12 are used, for example, based on the steepest descent method,

[0038]

(Equation 3)

As an instantaneous estimated value of

[0040]

(Equation 4)

Using, the evaluation function

[0042]

(Equation 5)

The optimum value of the vector y ₁ , which is the first speaker output signal vector that minimizes the following equation, is expressed by the following recurrence equation (11).
Is calculated by iterative calculation.

[0044]

(Equation 6)

[0045] However, y _lk ^': first spin at time k - Ka input signal e _m: m-th microphone output signal h _LMJ: first spin - force between-the m microphone impulse response j △ t time after Value L: Number of speakers M: Number of microphones J: Integer value indicating that the impulse response between all the speakers and microphones converges to 0 within a finite time Δt Also, the vector _yl = [y _{l 0 y l N-1 y} l N-2 ··· y l 1] T time series h _lm (k) = [server -h _{lm k 'bus} -h _{lm k' +} 1 ··· server -h _{lm N + 1} bar h _{lm 0} bar h _{lm 1} ... Bar h _{lm k'-1} ] ^T Further, bar h _{lm 0} = h _{lm 0} + h _{lm N} +... H _{lm QN} bar h _{lm 1} = h _{lm 1} + h _{lm N + 1} + ... h _{lm QN + 1}・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ bar h _{lm j-QN-1} = h _{lm j- QN-1 + h lm j- (} Q-1) N-1 + ··· + h lm j-1 server _{-h lm j-QN = h lm} j-QN + h lm j- (Q-1) N + ··・ +0 ・ ・· .... ..... ..... server _{-h lm N-1 = h lm} N-1 + h lm 2N-1 + ··· +0 l = 1,2, ····, L m = 1, 2,..., M Therefore, the recurrence equation (9) is replaced by the following equation (12).

[0046]

(Equation 7)

At this time, the processor performs the following four operation procedures at time k, for example.

Operation 11: Speaker input signal y _1k ^′ (k),
^{_{y 2k '(k), ····}} , y lk' (k) , respectively first spin - force, the second spin - Ka, ..., a L spin - operation to be output to the mosquitoes 12: Mike Output signals e ₁ (k), e ₂ (k),..., E _M (k)
, Respectively from the first microphone, the second microphone,..., The Mth microphone. Operation 13: The engine 2 input from the cycle measurement circuit 22
An integer value closest to a value obtained by multiplying the rotation cycle of 2 by Ord / △ t or 1 / (Ord △ Δt) is defined as N. Operation 14: 1 = 1, 2,... L and j = 0,
Calculation of recurrence formula (12) is performed for 1, 2,..., J-1.
・ ・ When using

[0049]

(Equation 8)

As the instantaneous estimated value of α, time series h _1k ^′ (k)
・ Using e _k ^' (k), the evaluation function is calculated based on the steepest descent method.

[0051]

(Equation 9)

The optimum value of the vector y ₁ , which is the first speaker output signal vector for minimizing the following equation, is expressed by the following recurrence equation (13).
Is calculated by iterative calculation. Vector y ₁ (k + ₁₎ = vector _{y 1 (k) -μ · α} · time series ^{_{h 1k "(k) · e}} k" (k) ···· (13) However, k "is, the k M Is a value obtained by adding 1 to the integer remainder obtained by dividing by 1. The recurrence formula (13) can be calculated in a shorter time than the recurrence formula (11).

Therefore, the recurrence equation (9) is replaced by the following equation (14). _{y 1 (k-J + QN} ) '(k + 1) = y 1 (K-j + QN)' (k) -μ · α · e k (k) · h 1k "j ····· ( 14) At this time, the processor performs, for example, the following four operation procedures at the time.

Operation 21: speaker input signal y _1k ^′ (k), y
_2k ^′ (k),..., Y _Lk ^′ (k)
, The second speaker,...,..., The L-th speaker. Operation 22: The microphone output signal e _k ^“ (k) is input from the k-th microphone. Operation 23: The engine 2 input from the cycle measurement circuit 22
An integer value closest to a value obtained by multiplying the rotation cycle of 2 by Ord / Δt or 1 / (Ord · Δt) is defined as N. Operation 24: 1 = 1, 2,..., L and j = 0,
The recurrence formula (14) is calculated for 1, 2,..., J-1. Therefore, the operation of the above algorithm is performed by using the recurrence formulas (9), (11) and (13), or the recurrence formulas (10), (12) and (1) obtained by simplifying these recurrence formulas.
Since it is only necessary to repeat the calculation of 4), the calculation time of the speaker input control can be shortened.

Next, the relation between the generation of the vibration for reduction and the audio will be described with reference to FIG. 4 and subsequent figures. First, in FIG.
The speaker 11 is used both for outputting the reduced vibration generated as described above and for outputting the audio signal A1 from the audio source 31. The amplifier 28 (power amplifier, in which the preamplifier and the main amplifier are not separately configured) is also used for outputting the vibration for reduction and for the audio signal A1 from the audio source 31. The output is also used.

The audio signal A1 passes through the switch 33 and the adder circuit 34 of the mixer circuit 32, and then passes through the amplifier 28.
Through the sound quality adjustment circuit 41 and the gain adjustment circuit 42 of FIG.
It is output from power 11. On the other hand, the ANC signal indicating the vibration for reduction from the control unit 20 of the control unit U is synthesized with the audio signal A1 through the adder circuit 34, and then transmitted through the sound quality adjustment circuit 41 and the gain adjustment circuit 42. -F1
1 is output. Reference numeral 44 denotes a tone adjustment dial, and reference numeral 45 denotes a gain adjustment dial, which is manually operated by an occupant.

The amplifier 28 includes a dial 44 or 45
Has an adjustment amount determining circuit 43 which receives a signal from the sound quality adjusting circuit 41 or the gain adjusting circuit 42 according to the operating state of the speaker 11 and indicates the output state of the speaker 11 caused by the audio operation of the speaker 11. . The adjustment amount determination circuit 43 outputs an adjustment amount signal C2 corresponding to an output change from the speaker 11 caused by the audio operation. The adjustment amount signal C2 is input to the switch 33 and the correction circuit 51 provided in the control unit 20. The switch 33 is normally closed while the adjustment amount signal C2 indicates zero (e.g.
(When there is no output request for the audio signal), the output is opened, and the output of the audio signal A1 to the adding circuit 34 is stopped. Further, the correction circuit 51 corrects the time series h in step S2 shown in FIG. 3 described above, as described later.

FIG. 5 shows an example of the correction by the correction circuit 51. In FIG. 5, when the gain of the amplifier 28 obtained from the adjustment amount signal C2 is g, the impulse response data h (i) is multiplied by g. FIG. 6 shows another example of the correction by the correction circuit. In FIG. 6, a frequency transfer function H is obtained by performing frequency analysis of the impulse response data h (i) (Q11), and a frequency characteristic change in the sound quality adjustment circuit 41 is performed on the obtained frequency transfer function H. G is multiplied by G (Q12) and the multiplied value is subjected to inverse Fourier transform to obtain the impulse response data again.
That is, the data is converted into the data h.

FIG. 7 shows that the correction circuit 52 to which the adjustment amount signal C2 is input corrects the convergence coefficient μ (see equation (12)) for optimizing the vector y in step S3 shown in FIG. The configuration is the same as that of FIG. 4 except for the portion shown in FIG. 7 (this also applies to FIG. 8 below). When the gain of the amplifier 28 obtained from the adjustment amount signal C2 is g, the convergence coefficient is corrected to g · μ by the correction circuit 52.

FIG. 8 shows a configuration in which the characteristic of the amplifier 23 for the microphone 12 is corrected by the correction circuit 53 which receives the input of the adjustment amount signal C2. Assuming that the gain of the amplifier 28 obtained from the adjustment amount signal C2 by the correction circuit 53 is g, the gain of the microphone amplifier 23 becomes “1/1”.
g ”times.

Although the embodiment has been described above, the vibration to be reduced is not limited to the engine vibration, but may be an appropriate signal which becomes a problem in the vehicle interior.

[Brief description of the drawings]

FIG. 1 is a top view of a vehicle to which the present invention is applied.

FIG. 2 is an overall control system diagram for generating a vibration for reduction.

FIG. 3 is a block diagram showing a configuration of a portion for optimizing the vibration for reduction in FIG. 2;

FIG. 4 is a diagram showing a relationship between an audio system and a control system for reducing vibration.

FIG. 5 is a diagram showing a correction example of the correction circuit shown in FIG. 4;

FIG. 6 is a diagram showing another correction example of the correction circuit shown in FIG. 4;

FIG. 7 is a diagram showing another correction circuit different from FIG. 4;

FIG. 8 is a diagram showing still another correction circuit different from FIGS. 4 and 7;

[Explanation of symbols]

 1: automobile 2: cabin 8: engine (vibration source) 11: speaker 12: microphone 23: microphone amplifier 28: speaker amplifier 31: audio source 32: mixer circuit 41: sound quality adjustment circuit 42: Volume adjustment circuit 43: Adjustment amount determination circuit 51 to 53: Correction circuit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-178845 (JP, A) JP-A-5-11773 (JP, A) JP-A-5-11779 (JP, A) 12454 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G10K 11/178 B60R 11/02 F01N 1/00 F01N 1/06 F16F 15/02 G10K 11/16 H04R 3/02

Claims (4)

(57) [Claims] 1. An audio signal from an audio unit
With an amplifier equipped with a sound quality adjustment circuit and a gain adjustment circuit
So that it can be amplified and output from speakers installed in the cabin
The A vibration control device for a vehicle in a vehicle, the passenger compartment from the speaker through the amplifier for the audio
Output means for outputting vibration for reduction inside the vehicle, a microphone for detecting vibration in the vehicle cabin, and an impulse response between the speaker and the microphone so as to reduce the vibration detected by the microphone. Optimizing means for optimizing the vibration for reduction, and operation for adjusting the sound quality or gain of the amplifier is not performed.
And a characteristic changing unit for changing a control characteristic for the optimization related to the impulse response in response to the content of the operation . 2. The method according to claim 1, wherein the optimizing means is configured to optimize the reduction vibration.
Impulse the transfer function between the microphone and the speaker
Comprising a conversion means for converting the response, the characteristic changing means changes a characteristic of said converting means, the vehicle vibration control system, characterized in that. 3. The method according to claim 1, wherein the optimizing unit is configured to control a distance between the microphone and the speaker.
The reduction oscillation is set to be optimized based on a product of an impulse response and a predetermined convergence coefficient, and the characteristic changing unit is configured to adjust the convergence coefficient and the impulse response.
A vibration control device for a vehicle , wherein only the convergence coefficient is changed . 4. The amplifier according to claim 1, wherein the microphone amplifier and the speaker amplifier are connected to each other.
And the characteristics of the two amplifiers correspond to the impulse response, respectively.
Answer is set as related to the optimization of the reduction vibration as the characteristic changing means changes the characteristics of the amplifier for the microphone, the vehicle vibration control system, characterized in that.