JP3144569B2 - Vehicle noise 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 noise control system for a vehicle, which can reduce noise in a vehicle interior and can create a seat where audio sound can be heard and a seat where audio sound cannot be heard.

[0002]

2. Description of the Related Art One of the methods for reducing the noise in the cabin of an automobile is to filter a reference signal related to the vibration of a noise source with an appropriate filter and generate a sound wave of the opposite phase from a speaker. An active noise control method that silences sound due to noise has been well known.

As one of the active noise control methods well known in the related art, there is a method using an LMS algorithm (Patent Application Publication No. 1-501344).
No.).

The LMS algorithm is to grasp a transfer function between the position of the detected microphone and the position of the speaker in advance, and to calculate and output a noise control sound wave having a phase opposite to that of the input sound wave. The filter coefficient vectors F ₁ , F ₂ ... Fm are successively updated using the following equation to obtain optimum noise reduction performance.

[0005]

(Equation 1)

Here, Fm: a filter coefficient vector for determining the output of the m-th speaker Hmn: a filter coefficient vector for giving a transfer characteristic between the m-th speaker and the n-th microphone x: a reference signal (the same frequency as the noise) Component: en: input signal from the n-th microphone μ: coefficient for determining the peripheral speed in equation (1) M: number of speakers N: number of microphones I: tap length of filter coefficient vector Fm J : Tap length of the filter coefficient vector Hmn k: Value at the k-th time point Further, the speaker output signal ym (k) of the m-th speaker is obtained by the following equation.

[0007]

(Equation 2)

If the speaker output signals obtained through the above equations (1) and (2) are generated from the respective speakers, the noise and the sound generated from the speakers cancel each other out at the respective microphone positions to obtain a noise reduction effect. It is done.

The above-described noise control by the LMS algorithm is also explained by a block diagram shown in FIG.

Here, the case of one speaker and one microphone is described as an example.

From the speaker 3, a control output z based on a speaker output y obtained by processing the reference signal x with a filter F (specified by an adaptive algorithm) is output. Noise d is observed,
The error signal e is input to the adaptive algorithm A. Further, the reference signal x is processed by the filter H that gives a speaker / microphone transfer characteristic, and is input to the adaptive algorithm A as a signal r. Therefore, the control output z output from the speaker 3 and the synthetic noise d cancel each other, so that a noise reduction effect can be obtained. Here, the filter F, the filter H, and the adaptive algorithm A constitute a signal generating unit for generating the speaker output y.

[0012] On the other hand, audio sound from an audio source is also output from a speaker installed in the passenger compartment, but there are situations in which some occupants do not want to hear (or do not want to hear) the audio sound. Also, in the case of a vehicle having a plurality of audio sources, the audio sound desired to be heard may differ depending on the occupant.

However, in the case of the conventional noise control, since only the noise in the passenger compartment is to be controlled, it is not possible to respond to the above-described passenger request.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and it is possible to control the noise in the vehicle interior and to make it possible to make the audio sound inaudible according to the occupant's preference. It is intended to be.

[0015]

According to the present invention, as means for solving the above-mentioned problems, microphones provided in each seat in a vehicle compartment for collecting sound in the vehicle compartment and an audio signal from an audio source are provided. A plurality of speakers for outputting, reference signal detecting means for detecting a reference signal related to vibration of a noise source, and a signal for generating a speaker output signal for reducing sound collected by the microphone based on the reference signal An audio signal line for subtracting an audio sound from the sound collected by each microphone on each signal input path for inputting a signal from each microphone to the signal generating means. And switch means are interposed between each audio signal line and the audio source. .

[0016]

According to the present invention, the following effects can be obtained by the above means.

That is, the audio sound can be heard or not heard at a specific seat by turning on or off the switch means while controlling the noise in the cabin.

[0018]

According to the present invention, a microphone provided on each seat in a vehicle interior for collecting sound in the vehicle interior, a plurality of speakers for outputting an audio signal from an audio source, and vibration of a noise source are provided. A noise control device for a vehicle, comprising: a reference signal detecting unit configured to detect a related reference signal; and a signal generating unit configured to generate a speaker output signal to reduce a sound collected by the microphone based on the reference signal. On each signal input path for inputting a signal from each of the microphones to the signal generating means, an audio signal line for subtracting an audio sound from the sound collected by each of the microphones is connected. Switch means are respectively provided between the audio source and the audio source, while controlling the noise in the vehicle interior,
By turning on or off the switch means, an audio sound can be heard or not heard in a specific seat. Therefore, it is possible to create a seat where the audio sound can be heard and a seat where the audio sound cannot be heard according to the occupant's preference. There is an excellent effect.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some preferred embodiments of the present invention will be described below with reference to the accompanying drawings. First Embodiment FIG. 2 shows a layout of each device in a vehicle compartment of an automobile provided with a noise control device according to a first embodiment of the present invention. Reference numeral 1 denotes a microphone that collects sound in the vehicle compartment; 2
Is a reference signal detecting means for detecting a reference signal related to the vibration of the noise source, 3 is a speaker for outputting a signal to reduce the sound collected by the microphone 1 based on the reference signal, and 4 is a power ON. / OFF
, An operation switch for designating an operation mode, an audio device 5 having an audio source incorporated therein, and a controller 6 acting as a signal generating means for generating a speaker output signal for noise control.

The microphones 1 are provided at two positions corresponding to the left and right ears of the occupant in the driver's seat on the front seat side, two positions corresponding to the left and right ears of the occupant in the front passenger's seat, and at the rear seat. A total of six are provided on the left and right sides of the rear part of the vehicle compartment.

As the reference signal detecting means 2, an acceleration sensor for detecting engine vibration which detects the vibration of an engine which is a noise source is used. Note that an ignition pulse detection circuit may be used instead of the acceleration sensor.

One speaker 3 is provided at the center of the front of the passenger compartment.
Two audio speakers are provided at the rear left and right of the vehicle compartment.

In describing the configuration and operation of the controller 6 having one audio source 5a (for example, radio) built into the audio equipment 5, one microphone 1 and a speaker 3 are provided for simplicity. One case will be described below with reference to FIG.

The controller 6 of this embodiment comprises a microprocessor such as a digital signal processor. The controller Fx processes the reference signal x detected by the reference signal detecting means 2, and the audio signal from the audio source 5a. a filter Fa for processing a, the reference signal x and the audio signal a
H and an adaptive algorithm A for determining filter coefficient vectors of the filters Fx and Fa
(In the case of the present embodiment, the LMS algorithm). Here, in the adaptive algorithm A, the above equation (1)
A filter coefficient vector is determined based on.

The filter H is a filter for giving a transfer characteristic between a speaker and a microphone. The filter H processes a reference signal x and an audio signal a and inputs the processed signal to the adaptive algorithm A as signals rx and ra.

From the speaker 3, a speaker output y obtained by synthesizing a noise control output obtained by processing the reference signal x by the filter Fx and an audio sound control output obtained by processing the audio signal a by the filter Fa; A control output z synthesized with the audio signal a from the audio source 5a is to be output.

On the other hand, in the microphone 1, the control output z and
Audio sounds d ₁ and interior noise d ₂ is observed with the synthetic noise d synthesized is input to the adaptive algorithm A as an error signal e = d + z.

According to the present embodiment, the sound collected by the microphone 1 (that is, the error signal e) is provided on the signal input path 11 for inputting a signal from the microphone 1 to the adaptive algorithm A in the controller 6. audio signal line 12 to the minus the audio sound d ₁ is connected. In addition,
In this embodiment, the audio signal line 12 is connected to the filter H
Are connected to an audio source 5a via an audio signal line 13 on the output side of the filter H and an audio signal line 14 on the input side of the filter H. A switch means 15 is provided on the audio signal line 12.

Next, the operation of the vehicle noise control device according to this embodiment will be described.

When the switch means 15 is in the OFF state,
From the speaker 3, the noise control output obtained by processing the reference signal x by the filter Fx and the audio signal a are filtered by the filter Fa.
A speaker output y obtained by synthesizing the audio sound control output processed in step 1 and a control output z obtained by synthesizing the audio signal a from the audio source 5a are output.
In the said control output z, and synthetic noise d audio sound d ₁ and interior noise d ₂ was synthesized was observed, the error signal e
= D + z is input to the adaptive algorithm A. Accordingly, since both the audio signal and the noise are to be controlled in the adaptive algorithm A, both are reduced and eliminated in the target seat.

On the other hand, when the switch means 15 is ON, a signal obtained by subtracting the audio signal from the error signal e sent from the microphone 1 to the adaptive algorithm A via the audio signal line 12 is input to the adaptive algorithm A. Becomes Therefore, the audio signal is excluded from the control target in the adaptive algorithm A, and the noise reduction is performed at the target seat, but the audio sound is not deleted.

That is, in the case of this embodiment, the switch means 15 is turned on or off while controlling the noise in the vehicle interior.
As a result, audio sound can be heard or not heard in a specific seat, and seats that can hear audio sound and seats that cannot hear audio sound can be made according to the occupant's preference.

Second Embodiment FIG. 3 shows a controller in a vehicle noise control device according to a second embodiment of the present invention. Also in this case, for simplicity, it is assumed that there is one microphone 1 and one speaker 3.

In the case of this embodiment, the audio equipment 5 has two types of audio sources 5a and 5b (for example, a radio and a CD player).

Therefore, in the case of this embodiment, the controller 6
The filter processing and the filter Fx for processing a reference signal x which is detected by the reference signal detection unit 2, the audio signal a ₁ from the audio source 5a Fa
_1, a filter Fa ₂ for processing an audio signal a ₂ from the audio source 5b, a filter H for processing the reference signal x and an audio signal a _1, a _2, of the filter Fx, Fa ₁ and Fa ₂ filter An adaptive algorithm A (LMS algorithm in this embodiment) for determining a coefficient vector is provided.

[0036] Then, from the speaker 3, the noise control output obtained by processing a reference signal x by the filter Fx and audio signals a ₁ and a first audio sound control output processed by the filter Fa ₁ audio signal a ₂ filter Fa ₂ A speaker output y obtained by synthesizing the second audio sound control output processed in the above and a control output z obtained by synthesizing the audio signal a from the audio source 5a are output.

On the other hand, in the microphone 1, the control output z and
The first audio sound da ₁ from the audio source 5a, a synthetic noise d second audio sound db ₁ and interior noise d ₂ is synthesized from the audio source 5b is observed, the adaptation algorithm A as an error signal e = d + z Is input to

According to the present embodiment, the sound collected by the microphone 1 (that is, the error signal e) is provided on the signal input path 11 for inputting a signal from the microphone 1 to the adaptive algorithm A in the controller 6. an audio signal line 12a to the minus the first audio sound da _1, collected sounds with the microphone 1 (i.e., the error signal e) second audio from db ₁
Is connected to an audio signal line 12b for subtracting the value. In this embodiment, the audio signal lines 12a,
Reference numeral 12b denotes an audio source 5a, via an audio signal line 13a, 13b on the output side of the filter H and an audio signal line 14a, 14b on the input side of the filter H.
5b. The audio signal line 1
Switch means 15a and 15b are interposed in 2a and 12b, respectively.

With the above configuration, when the switch means 15a and 15b are in the OFF state, both the audio signal and the vehicle interior noise are reduced and eliminated in the target seat as in the first embodiment. When one of the switch means 15a and 15b is in the OFF state, only one of the audio sources 5a and 5b is reduced and deleted in the target seat. When both of the switch means 15a and 15b are in the ON state, neither of the audio sources 5a and 5b is deleted in the target seat.

That is, in the case of this embodiment, a specific audio sound may or may not be heard at a specific seat by turning on or off one or both of the switch means 15a and 15b while controlling the noise in the vehicle cabin. It is possible to make a seat that can hear a specific audio sound and a seat that cannot hear it according to the occupant's preference.

In the above embodiment, the LMS algorithm is used to generate the output signal of the speaker, but other signal generation methods can be adopted.

The invention of the present application is not limited to the configuration of each of the above embodiments, and it is a matter of course that the design can be changed as appropriate without departing from the gist of the invention.

[Brief description of the drawings]

FIG. 1 is a block diagram of a controller portion in a vehicle noise control device according to a first embodiment of the present invention.

FIG. 2 is a layout diagram illustrating an overall configuration of the vehicle noise control device according to the first embodiment of the present invention.

FIG. 3 is a block diagram of a controller part in the vehicle noise control device according to the embodiment of the present invention.

FIG. 4 is a block diagram of a controller part in the conventional noise control noise.

[Explanation of symbols]

1 is a microphone, 2 is a reference signal detecting means, 3 is a speaker, 5 is an audio device, 5a and 5b are audio sources, 6 is a signal generating means, a controller, 11 is a signal input path, and 12, 12a and 12b are audio signal lines. , 15,1
5a and 15b are switch means.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G10K 11/178 B60R 11/02 G10L 15/20

Claims (1)

(57) [Claims] 1. A microphone provided in each seat in a vehicle interior for collecting sound in the vehicle interior, a plurality of speakers for outputting an audio signal from an audio source, and detecting a reference signal related to vibration of a noise source. A vehicle-mounted noise control device, comprising: a reference signal detecting unit that generates a loudspeaker output signal to reduce a sound collected by the microphone based on the reference signal; An audio signal line for subtracting an audio sound from the sound collected by the microphone is connected to each signal input path for inputting a signal from the microphone to the signal generation means. A vehicle noise control device, wherein switch means are interposed between the source and the source.