JPH0580788A - Noise controller for vehicle - Google Patents

Abstract

PURPOSE:To eliminate an audio sound as a person on a car desires while performing noise control on the car. CONSTITUTION:This vehicle noise controller is equipped with microphones 1, 1 which are provided at the seats on the car and gather the sound on the car, plural speakers 3, 3, which output audio signals from an audio source 5, a reference signal detecting means 2 which detects a reference signal regarding the vibration of a noise source, and a signal generating means 6 which generates a speaker output signal for reducing the sounds gathered by the microphones according to the reference signal. An audio signal line 12 which subtracts an audio sound from a sound gathered by each microphone 1 is connected to each of signal input paths 11 for inputting the signals from the respective microphones 1 to the signal generating means 6 and a switch means 15 is interposed between each audio signal line 12 and the audio source 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle noise control device capable of reducing noise in a vehicle compartment and making a seat in which an audio sound can be heard and a seat in which an audio sound cannot be heard.

[0002]

2. Description of the Related Art One of the methods for reducing the noise in the interior 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 having a phase opposite to that of the reference signal from a speaker. BACKGROUND ART Active noise control methods for muting sound have been conventionally well known.

By the way, as one of the well-known active noise control methods, there is one using the LMS algorithm (Patent Application Publication No. 1-501344).
No.).

The LMS algorithm is a means for grasping a transfer function between a detected microphone position and a speaker position in advance and calculating and outputting a noise control sound wave having a phase opposite to that of an input sound wave, and is incorporated in a controller. The filter coefficient vectors F ₁ , F _2, ..., Fm are sequentially updated by using the following equation to obtain the optimum silencing performance.

[0005]

[Equation 1]

Here, Fm: a filter coefficient vector for determining the output of the m-th speaker Hmn: a filter coefficient vector giving a transfer characteristic between the m-th speaker and the n-th microphone x: reference signal (the same frequency as noise Signal including components) en: Input signal from the nth microphone μ: Coefficient for determining the peripheral speed of equation (1) M: Number of speakers N: Number of microphones I: Tap length of filter coefficient vector Fm J : Tap length k of the filter coefficient vector Hmn: Value at the k-th time 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 signal obtained through the above equations (1) and (2) is generated from each speaker, noise and sound generated from the speaker cancel each other at each microphone position, and a muffling effect is obtained. Be done.

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

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

The speaker 3 outputs the control output z based on the speaker output y obtained by processing the reference signal x with the filter F (specified by the adaptive algorithm), and the microphone 1 synthesizes the control output z with the control output z. 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 the transfer characteristic between the speaker and the microphone, and is input to the adaptive algorithm A as the signal r. Therefore, the control output z output from the speaker 3 and the synthetic noise d cancel each other out, and a silencing effect is obtained. Here, the filter F, the filter H, and the adaptive algorithm A constitute the signal generation means for generating the speaker output y.

On the other hand, although the audio sound from the audio source is also output from the speaker installed in the vehicle compartment, there are circumstances where some passengers do not want to hear the audio sound (or it is desirable not to hear it). Further, in the case of a vehicle provided with a plurality of audio sources, the occupant may hear different audio sounds.

However, in the case of the conventional noise control, only the noise in the vehicle compartment is targeted for control, so that it is not possible to meet the above-mentioned passenger requirements.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to make the audio sound inaudible in accordance with the occupant's preference while controlling the noise in the passenger compartment. The purpose is to

[0015]

Means for Solving the Problems In the present invention, as means for solving the above problems, a microphone provided in each seat in the passenger compartment for collecting sound in the passenger 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 the sound collected by the microphone based on the reference signal. In a vehicle noise control device including a generation unit, an audio signal line for subtracting an audio sound from a sound collected by each microphone on each signal input path for inputting a signal from each of the microphones to the signal generation unit. Respectively, and switch means are respectively provided between the audio signal lines and the audio source. .

[0016]

In the present invention, the following actions are obtained by the above means.

That is, while controlling the noise in the passenger compartment, the audio sound can be heard or not heard in a specific seat by turning the switch means ON or OFF.

[0018]

According to the present invention, a microphone provided in each seat in the passenger compartment for collecting sound in the passenger compartment, a plurality of speakers for outputting an audio signal from an audio source, and a vibration of a noise source. A vehicle noise control device comprising: a reference signal detecting means for detecting a related reference signal; and a signal generating means for generating a speaker output signal for reducing a sound collected by the microphone based on the reference signal. An audio signal line for subtracting an audio sound from a sound collected by each microphone is connected to each signal input path for inputting a signal from each of the microphones to the signal generating means, and each audio signal line is connected to the audio signal line. Switch means are provided between the audio source and the audio source to control the noise in the passenger compartment.
By turning the switch means ON or OFF, the audio sound can be heard or not heard in a specific seat. Therefore, it is possible to create a seat in which the audio sound can be heard and a seat in which 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 interior of a vehicle equipped 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 interior, Two
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 for reducing the sound collected by the microphone 1 based on the reference signal, and 4 is a power source ON / OFF
And 5 are operation switches for designating an operation mode, 5 is an audio device in which an audio source is incorporated, and 6 is a controller which functions as a signal generating means for generating a speaker output signal for noise control.

The microphones 1 are located at two positions corresponding to the left and right ears of the occupant in the driver's seat on the front seat side, at the positions corresponding to the left and right ears of the occupant in the front passenger seat, and at the rear seat. There are a total of six, two on the left and right on the rear of the passenger compartment.

As the reference signal detecting means 2, an engine vibration detecting acceleration sensor for detecting the vibration of the engine, which is a noise source, is used. 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 on the left and right of the rear part of the passenger compartment.

In explaining the structure and operation of the controller 6 in which one audio source 5a (for example, radio) is built in the audio device 5, for simplification, one microphone 1 and speaker 3 are provided. The case of one will be described below with reference to FIG.

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

The filter H is a filter for giving a transfer characteristic between a speaker and a microphone, processes the reference signal x and the audio signal a, and inputs them 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 with the filter Fx and an audio sound control output obtained by processing the audio signal a with the filter Fa, A control output z, which is a composite of 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
The audio sound d ₁ and the vehicle interior noise d ₂ and the synthesized noise d are observed and input to the adaptive algorithm A as an error signal e = d + z.

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

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

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

On the other hand, when the switch means 15 is in the ON state, 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 removed from the control target in the adaptive algorithm A, and the noise is reduced and erased in the target seat, but the audio sound is not erased.

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.
By this, it is possible to hear or not to hear the audio sound in a specific seat, and it is possible to make a seat in which the audio sound can be heard and a seat in which the audio sound cannot be heard depending on the occupant's preference.

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

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

Therefore, in the case of this embodiment, the controller 6
Is a filter Fx for processing the reference signal x detected by the reference signal detecting means 2 and a filter Fa for processing the audio signal a ₁ from the audio source 5a.
_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 the case of this embodiment) for determining a coefficient vector is provided.

From the speaker 3, the noise control output obtained by processing the reference signal x with the filter Fx and the first audio sound control output obtained by processing the audio signal a ₁ with the filter Fa ₁ and the audio signal a ₂ are obtained by the filter Fa ₂ The speaker output y obtained by synthesizing the second audio sound control output processed in step a and the control output z obtained by synthesizing the audio signal a from the audio source 5a are to be 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, the second audio sound db ₁ from the audio source 5b, and the synthesized noise d _{2 that} is a synthesis of the vehicle interior noise d ₂ are observed, and the adaptive algorithm A is used as the error signal e = d + z. Entered in.

Therefore, in this embodiment, the sound (that is, the error signal e) collected by the microphone 1 is input to the signal input path 11 for inputting the signal from the microphone 1 to the adaptive algorithm A in the controller 6. From the audio signal line 12a that subtracts the first audio sound da ₁ and the sound collected by the microphone 1 (that is, the error signal e) to the second audio db ₁
Is connected to the audio signal line 12b for minus. In this embodiment, the audio signal line 12a,
The audio source 5a, 12b passes through the audio signal lines 13a, 13b on the output side of the filter H and the audio signal lines 14a, 14b on the input side of the filter H.
It is connected to 5b. Also, the audio signal line 1
Switch means 15a and 15b are provided on the 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 erased in the target seat as in the first embodiment. When one of the switch means 15a, 15b is in the OFF state, only one of the audio sources 5a, 5b is reduced and erased in the target seat. Further, when both the switch means 15a and 15b are in the ON state, neither of the audio sources 5a and 5b is erased in the target seat.

That is, in the case of the present embodiment, while controlling the noise in the vehicle compartment, by turning on or off one or both of the switch means 15a, 15b, a specific audio sound may or may not be heard in a specific seat. It is possible to create a seat in which a specific audio sound can be heard and a seat in which a specific audio sound cannot be heard, depending on 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-described embodiments, and it goes without saying that the design can be appropriately changed without departing from the scope of the invention.

[Brief description of 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 showing an overall configuration of the vehicle noise control device according to the first exemplary embodiment of the present invention.

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

FIG. 4 is a block diagram of a controller portion in 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 1212a and 12b are audio signal lines. , 15,1
5a and 15b are switch means.

Claims (1)

[Claims] 1. A microphone provided in each seat in a vehicle compartment for collecting sound in the vehicle compartment, a plurality of speakers outputting an audio signal from an audio source, and a reference signal related to vibration of a noise source. A noise control device for a vehicle, comprising: a reference signal detecting unit for generating a speaker output signal for reducing a sound collected by the microphone based on the reference signal; Audio signal lines for subtracting audio sound from the sounds collected by the microphones are respectively connected on the signal input paths for inputting signals to the signal generating means from the audio signal lines and the audio signals. A vehicle noise control device characterized in that switch means are respectively provided between the source and the source.