JPH0627971A - In-cabin indistinct sound reducing device - Google Patents

Abstract

PURPOSE:To provide the in-cabin indistinct sound reducing device which effectively perform stable and delicate noise reduction by finding speaker/microphone transmission characteristics without requiring troublesome operation and giving an unpleasant feeling. CONSTITUTION:A primary source PSE which is highly correlative with an engine vibration sound is inputted to adaptive filters 11 and 12 and unmanned state transmission characteristic setting circuits 17a, 18a, 19a, and 20a and outputted as canceling sounds from speakers 13 and 14 and the noise reduced state at a listening point is detected as error signals by error microphones 15 and 16 and inputted to LMS(Least Mean Square) arithmetic circuits 21 and 22. The signals which are corrected by the unmanned state transmission characteristic setting circuits 17a, 18a, 19a, and 20a, on the other hand, are corrected by on-car person influence characteristic circuits 17b, 18b, 19b, and 20b previously stored with the influence of a person on the car and inputted to the LMS arithmetic circuit 21 and 22 to update the filter coefficients of the adaptive filters 11 and 12 so that the error signals become minimum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle interior muffler noise reducing apparatus for reducing the muffler noise generated in the vehicle compartment due to the vibration noise of an engine by interfering with the canceling noise.

[0002]

2. Description of the Related Art In addition to vehicle interior noise that is mainly caused by engine vibration noise, a sound (cancellation sound) having the same amplitude and opposite phase to this noise is produced from an additional sound source to reduce vehicle interior noise. The technology of is proposed.

As such a technique, for example, Japanese Patent Laid-Open No. Hei 3
No. 5255, numerical data of a basic sine wave having an opposite phase in synchronism with a secondary component of engine rotation is stored in advance, and the engine rotation speed obtained from a crank angle sensor and the engine obtained from a pressure sensor are stored. By modifying the phase and amplitude of the basic sine wave with the load, there is shown a vehicle interior muffler noise reduction device that can create a canceling sound without the need for a vibration sensor or the like that directly detects engine vibration and the like. .

Recently, LMS (Least Mean S)
quare) algorithm (the theory that the mean squared error is approximated by the instantaneous squared error by utilizing the recursive formula of the filter to simplify the formula for finding the optimum filter coefficient), or this LMS MEFX-LMS (Multipl) with the algorithm expanded to multiple channels
A vehicle interior muffler noise reduction apparatus using an e-Error Filtered X-LMS algorithm has begun to be put into practical use.
In the vehicle interior muffler noise reduction device using this LMS algorithm, when the vehicle interior noise generated mainly due to engine vibration is silenced, a signal highly correlated with the engine vibration is detected as a noise vibration source signal (primary source), A canceling sound is generated from the speaker by synthesizing a canceling sound signal (cancellation signal) for noise from the primary source by an optimum filter. Then, the noise reduction state at the listening point is detected as an error signal by the error microphone, and the error signal and the speaker / microphone transfer characteristic Cmn (m
Is a microphone and n is a primary source corrected by a numerical value of a speaker) and the LMS algorithm is used to update the filter coefficient of the optimum filter to optimize the noise reduction at the listening point. This LM
According to the vehicle interior muffler noise reducing apparatus that uses the S algorithm, more stable and finer noise reduction can be realized as compared with the vehicle interior muffler noise reducing apparatus described above.

[0005]

By the way, the above LMS
In order to realize effective noise reduction by the vehicle interior muffler noise reduction device using an algorithm, the speaker / microphone transfer characteristic Cmn that changes depending on the seating condition of the occupant, the temperature inside the vehicle, the humidity inside the vehicle, and the change over time. Must be set correctly. For this reason, conventionally, after the occupant has been seated, the occupant has to set in advance by system identification before the operation of the muffler noise reduction device in the passenger compartment.
That is, as shown in the conceptual diagram of FIG. 7, the unknown system 1 is provided between the error microphone and the speaker when the occupant is seated.
And a random noise RN containing a predetermined frequency component,
It is input to the unknown system 1 and a transfer characteristic setting circuit (Cmn setting circuit) 2 having an updatable transfer characteristic Cmn. The random noise RN input to the unknown system 1 is generated as a sound from a speaker, reaches the error microphone under the influence of the actual speaker / microphone transfer characteristic, and is detected. Then, the signal detected by the error microphone and the signal output from the Cmn setting circuit 2 are input to the LMS circuit 3 as an overlay error signal so that the LMS circuit 3 minimizes the error signal. By updating the transfer characteristic Cmn of the Cmn setting circuit 2, the actual speaker / microphone transfer characteristic is estimated.
In the case of having a plurality of speakers, the above work is performed independently for each speaker.

However, such a work is very troublesome, and random noise is generated to identify the system, which causes an unpleasant occupant.

Further, in order to eliminate such troublesome work and discomfort to the occupant, it is conceivable to set the transmission characteristic between the speaker and the microphone to a fixed value based on the results of experiments and the like. Changes and cushions inside the car,
There is a problem that the speaker / microphone transfer characteristic may deviate from the actual transfer characteristic value depending on the arrangement of accessories such as accessories and child seats. If the speaker / microphone transfer characteristic is set to avoid such a problem, other Under the above condition, there is a large deviation from the actual transmission characteristics between the speaker and the microphone, and there is a possibility that the original capability of the vehicle interior muffler noise reduction device that uses the LMS algorithm may not be fully exerted.

The present invention has been made in view of the above circumstances, and the inside environment of the passenger such as the seated state of the passenger, the temperature inside the vehicle, the humidity inside the vehicle, the change over time, and the arrangement of fixtures, etc., without giving the passenger any troublesome work or discomfort. It is an object of the present invention to provide a vehicle interior muffled sound reduction device capable of accurately obtaining a speaker / microphone transfer characteristic that changes due to, and effectively and stably reducing fine noise.

[0009]

In order to achieve the above object, a vehicle interior muffled noise reducing apparatus according to the present invention comprises a cancel signal synthesizing means for synthesizing a noise vibration source signal having a high correlation with engine vibration as a cancel signal by an adaptive filter. , A canceling sound generating means for generating the canceling signal from the sound source as a canceling sound for noise, an error signal detecting means for detecting a noise reduction state at the listening point as an error signal, and the canceling sound generating means at any time in the absence of an occupant in advance. And an unmanned state transfer characteristic setting means for setting a transfer characteristic between the error signal detection means and the unmanned state transfer characteristic, and an effect of a seating state of an occupant on the unmanned state transfer characteristic is stored in advance and set as an occupant influence characteristic. Occupant influence characteristic memory setting means, and the noise vibration source signal to the unmanned state transfer characteristic and the occupant influence characteristic. Correcting, in which a cancellation signal updating means for updating the filter coefficients of the adaptive filter on the basis of this correction the noise vibration source signal and the error signal.

[0010]

[Operation] In the above configuration, first, the unmanned state transfer characteristic setting means sets the transfer characteristic between the canceling sound generating means and the error signal detecting means as an unmanned state transfer characteristic in advance in the absence of an occupant. After the occupant is seated, the occupant influence characteristic storage setting means sets the influence of the occupant's seating state stored in advance on the unmanned state transfer characteristic as the occupant influence characteristic from the seated state of the occupant. next,
When engine vibration noise occurs, the cancel signal synthesizing means synthesizes a noise vibration source signal having a high correlation with the engine vibration as a cancel signal by an adaptive filter, and the canceling sound generating means cancels the canceling signal against the noise. Generated from the sound source. Then, the error signal detecting means detects the noise reduction state at the listening point as an error signal, and inputs this error signal to the cancel signal updating means. On the other hand, the noise vibration source signal is corrected by the unmanned state transfer characteristic and the occupant influence characteristic and input to the cancel signal updating means, and the cancel signal updating means corrects the noise vibration source signal and the error signal. Based on and, the filter coefficient of the adaptive filter is updated.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show an embodiment of the present invention, FIG. 1 is a schematic system diagram of a vehicle interior muffler noise reduction device, and FIG. 2 is a schematic explanatory diagram when the vehicle interior muffler noise reduction system is installed in a vehicle. FIG. 3 is a conceptual diagram of initial setting of unmanned speaker / microphone transfer characteristics, FIG. 4 is a conceptual diagram of initial setting of occupant influence characteristics, and FIG. 5 is a conceptual view of unattended speaker / microphone transfer characteristics before use. FIG. 6 is a conceptual explanatory diagram of an unmanned speaker / microphone transmission characteristic and an occupant influence characteristic.

In the figure, reference numeral 10 denotes a vehicle interior muffled noise reducing apparatus. The vehicle interior muffled noise reducing apparatus 10 is a noise vibration source having a high correlation with engine-related indoor vibration noise generated by an engine (not shown). Signal (primary source) P
Adaptive filters 11 and 12 as two cancellation signal synthesizing means to which SE is input, and these adaptive filters 1
D / A converters and amplifiers 1 and 12 (neither shown)
1 as a canceling sound generation means connected via
3 and 14, two error microphones 15 and 16 as error signal detecting means for detecting the noise reduction state at the listening point as an error signal, and four speaker / microphone transfer characteristic estimation circuits to which the primary source PSE is input. 17,
18, 19, 20 and signals from the speaker / microphone transfer characteristic estimating circuits 17, 18 and the error microphone 1
The error signals from 5 and 16 are input, and LMS (Least) as a cancel signal updating means capable of updating the filter coefficient of the adaptive filter 11 based on these signals.
Mean Square) arithmetic circuit 21, the signals from the speaker / microphone transfer characteristic estimation circuits 19 and 20 and the error signals from the error microphones 15 and 16 are input, and the adaptive filter 12 of the adaptive filter 12 is based on these signals. It is composed of an LMS operation circuit 22 as a cancel signal updating means capable of updating the filter coefficient.

The adaptive filters 11, 12 and the speaker / microphone transfer characteristic estimation circuits 17, 18, 19, 2
The primary source PSE input to 0 and 0 is, for example, a signal obtained by shaping and processing a signal from an ignition pulse, a fuel injection pulse, a crank angle sensor (not shown), or the like in a predetermined manner, or an engine load based on these signals. It is a signal that reflects information and has a high correlation with engine vibration noise.

Further, the adaptive filter 11 has the L
F in which the filter coefficient is updated by the MS operation circuit 21
An IR (Finite Impulse Response) filter has a predetermined number of taps, and the primary source PSE input to the adaptive filter 11 is convolution product summed with the filter coefficient and output as a cancel signal to the D / A converter. A canceling sound is generated from the speaker 13, which is an additional sound source, through an amplifier (neither is shown). Similarly, the adaptive filter 12 also
The FIR filter whose filter coefficient is updated by the LMS operation circuit 22 has a predetermined number of taps and is input to the adaptive filter 12 by the primary source P.
SE is generated as a canceling sound from the speaker 14 which is an additional sound source through the D / A converter as a cancellation signal which is convolution product summed with the above filter coefficient and is output to the D / A converter (neither is shown). ing.

The speakers 13 and 14 are arranged, for example, at a front door (not shown) or the like, and the listening point (for example, the position near the ears of the passenger in the passenger seat 26 and the driver in the driver's seat 27) in the passenger compartment. The error microphones 15 and 16 are provided at positions (close to the ears). The error microphones 15 and 16 detect the result of the interference between the vibration noise and the canceling sound, and input the result to the LMS operation circuits 21 and 22 as an error signal.

Further, the LMS arithmetic circuit 21 obtains an instantaneous square error from the error signals from the error microphones 15 and 16 and the signals from the speaker / microphone transfer characteristic estimating circuits 17 and 18, and Each error microphone 15,
The filter coefficient of the adaptive filter 11 is updated so that the error signal from 16 is minimized, and the LMS arithmetic circuit 22 similarly receives the error signals from the error microphones 15 and 16, The filter correction amount is obtained from the signals from the speaker / microphone transfer characteristic estimation circuits 19 and 20 to obtain the error microphones 15 and 16 described above.
The filter coefficient of the adaptive filter 12 is updated so as to minimize the error signal from.

The speaker / microphone transfer characteristic estimation circuits 17, 18, 19, 20 are unmanned state transfer characteristic setting circuits (C'0mn circuits) 17a, 18a, 19a as unmanned state transfer characteristic setting means. 20a and occupant influence characteristic circuits (CXmn circuits) 17b, 18b, 19b, 20b. These CXmn circuits 17b, 18
b, 19b, and 20b, the occupant influence characteristic memory setting circuit 23
Are connected. In addition, m of the C'0mn circuit and the CXmn circuit indicates the microphone number of each of the error microphones 15 and 16 (error microphone 15 is No. 1 and error microphone 16 is No. 2), and n is each of the above. The speaker numbers of the speakers 13 and 14 (the speaker 13 is No. 1 and the speaker 14 is No. 2) are shown. That is, the speaker / microphone transfer characteristic between the speaker 13 and the error microphone 15 is C1.
1. The speaker / microphone transfer characteristic between the speaker 13 and the error microphone 16 is C21, and the speaker 14 is
The speaker / microphone transfer characteristic between the error microphone 15 and the error microphone 15 is C12, and the speaker 14 and the error microphone 1 are
The transmission characteristic between the speaker and the microphone between 6 and 6 is C22,
The above-mentioned C'0mn circuits are C'011 circuits 17a and C'0, respectively.
21 circuit 18a, C'012 circuit 19a, C'022 circuit 20a. Further, each of the above CXmn circuits is CX11.
Circuit 17b, CX21 circuit 18b, CX12 circuit 19b, C
It is shown by the X22 circuit 20b.

Further, the occupant influence characteristic memory setting circuit 2 described above.
3 is an occupant seating determination circuit 23a to which a seating sensor A24 for detecting seating of an occupant and a seating sensor B25 are connected,
Occupant influence characteristics C under various combination conditions of seated occupants
Xmn is stored in advance, and the CXmn circuits 17b, 18b, 19b, 2 are generated by the signal from the passenger seating determination circuit 23a.
0b, the occupant influence characteristic memory setting circuit (CX memory setting circuit) 23b capable of setting the occupant influence characteristic CXmn, and the occupant influence characteristic memory setting circuit 23 and the CXmn circuit 17 described above.
b, 18b, 19b, and 20b form an occupant influence characteristic memory setting means.

The seating sensor A24 is installed inside the seat of the passenger seat 26, and the seating sensor B25 is installed inside the seat of the driver seat 27.
Then, the seated state of the occupant is detected. As the seating sensors A and B, for example, an optical sensor such as an infrared sensor or a weight sensor using a load cell may be used. Further, when a sensor such as a load cell that can detect the weight is used, it is possible to determine whether the occupant seated by the weight is a child or an adult, and thus the seated state of the occupant can be detected more finely. Furthermore, by using an optical sensor such as an infrared sensor and a weight sensor such as a load cell in combination, the seated state of the occupant can be detected more reliably and finely. Further, the seating sensor in the driver's seat need not be provided in the driver's seat as long as the ON state of the ignition switch is detected as a state in which the driver is seated.

Here, each of the C'0mn circuits 17a and 18 described above.
a, 19a, 20a and the above CXmn circuits 17b, 18
Setting of characteristic values b, 19b, and 20b will be described with reference to the conceptual diagrams of FIGS.

First, as shown in FIG. 3, an unknown system (actual transfer characteristic C0m) is provided between the error microphones 15 and 16 and the speaker 13 which are in an unmanned state in an initial stage (for example, before shipment).
unknown system 31a having n1) and the random noise RN containing a predetermined frequency component
a and a transfer characteristic setting circuit (C0mn setting circuit) 32 having an updatable transfer characteristic C0mn (C011, C021). The random noise RN input to the unknown system 31a is generated as a sound from the speaker 13, reaches the error microphones 15 and 16 under the influence of the actual speaker / microphone transfer characteristic (C0111, C0211), and is detected. Then, the signals detected by the error microphones 15 and 16 and the signal output from the C0mn setting circuit 32 are input to the LMS circuit 33 as a superposition error signal, and the LMS circuit 33 determines that the error signal is the minimum. The transfer characteristic C0mn of the C0mn setting circuit 32 is updated so that the value becomes the initial unmanned speaker / microphone transfer characteristic C011.
, C021. Similarly, system identification is performed between the error microphones 15 and 16 and the speaker 14 as an unknown system, and initial unmanned speaker / microphone transfer characteristics C012 and C022 are set.

Next, as shown in FIG. 4, an unknown system (such as before shipment, etc.) between the error microphones 15 and 16 and the speaker 13 in the manned state (for example, only the driver is seated) ( An unknown system) 31b having an actual transfer characteristic C0mn2, and a random noise RN including a predetermined frequency component is added to the unknown system 31b and C0m.
and an occupant influence characteristic setting circuit (CXmn setting circuit) 34 which is connected in series to the n setting circuit 32 and has an occupant influence characteristic CXmn (CX11, CX21) that can be updated. The random noise RN input to the unknown system 31b is generated as a sound from the speaker 13 and reaches the error microphones 15 and 16 under the influence of the actual speaker / microphone transfer characteristic (C0112, C0212) and is detected. The signal detected by the error microphones 15 and 16 and the signal output from the CXmn setting circuit 34 are input to the LMS circuit 33 as a superposition error signal, and the LMS circuit 33
Then, the occupant influence characteristic CXmn of the CXmn setting circuit 34 is updated so as to minimize this error signal, and this value is set as the occupant influence characteristics CX11, CX21. Similarly to this,
A system is identified between the error microphones 15 and 16 and the speaker 14 as an unknown system, and the occupant influence characteristic C
Set X12 and CX22. In addition, the system identification is performed even when the occupant is seated in the passenger seat, and the occupant influence characteristic CXm
The occupant influence characteristic C thus obtained by measuring n
Xmn is stored in the CX storage setting circuit 23b. still,
It is possible to set the number of combinations of occupant seating conditions obtained here as many as the number of combinations that can be detected by the seating sensor used. Further, in this embodiment, the number of error microphones is set to "driver only", "driver, passenger occupant".
However, if two more error microphones are installed on the rear seat side to reduce the noise of the rear seat occupant, "driver only", "driver,""Passenger seat occupant", "Driver, driver side rear seat occupant", "Driver, passenger side rear seat occupant", "Driver,
"Passenger seat passenger, rear passenger seat on driver side", "Driver, passenger passenger, rear passenger seat on passenger side", "Driver, rear passenger seat on driver side, rear passenger passenger on passenger side", "driver" , Passenger seat occupant, driver seat rear seat occupant, passenger seat rear seat occupant ”may be obtained and stored in advance.

After shipment, as shown in FIG. 5, the unattended state of the passenger before or after getting off is detected, and the unattended state between the error microphones 15 and 16 and the speaker 13 or between the speaker 14 is detected. An unknown system (unknown system having an actual transfer characteristic C0mn3) 31c is used as the unknown system, and similarly to the setting of the initial unattended speaker / microphone transfer characteristic C0mn, the unattended speaker / microphone transfer characteristic before use C'0mn ( C'011, C'021, C'012, C'022) are set at any time.

That is, as shown in FIG. 6, the impulse response in the initial manned state is obtained from the correction by the initial unmanned speaker / microphone transfer characteristic C0mn and the correction by the occupant influence characteristic CXmn. Obtain the transfer characteristic C0mn between the unattended speaker / microphone and
The occupant influence characteristic CXmn is obtained in advance from the value of n and stored. Then, the speaker / microphone transmission characteristic setting circuit C'0mn is obtained at any time in an unmanned state such as before use in a vehicle, and the influence of the occupant is corrected by the occupant influence characteristic CXmn stored in advance.
By performing the above, the accurate transmission characteristic between the speaker and the microphone is obtained before the operation of the noise reduction system.

Next, the operation of the embodiment having the above structure will be described. First, as described above, the initial unattended speaker / microphone transfer characteristics C011 and C021 between the unattended error microphones 15 and 16 and the speaker 13 in the initial stage (for example, before shipment), and the error microphones 15 and 16 and the speakers. After obtaining the initial unattended speaker / microphone transfer characteristics C012 and C022 between 14 and 14 by system identification,
These initial unattended speaker / microphone transfer characteristics C0m
n (C011, C021, C012, C022) is used to combine each seating condition (for example, "driver only", "driver,
Passenger characteristics "CXmn (CX11
, CX21, CX12, CX22) are obtained by system identification and stored in advance in the CX storage setting circuit 23b. After shipment, the unmanned state of the passenger before or after getting off is detected, and the error microphones 15 and 1 in the unmanned state are detected.
Before use unattended speaker / microphone transfer characteristics C'011 and C'021 between the speaker 6 and the speaker 13 and before use unattended speaker / microphone between the error microphones 15 and 16 and the speaker 14. Transfer characteristics C'012 and C'022 are obtained by system identification, and these values are calculated in the C'0mn circuit (C'011
Circuit 17a, C'021 circuit 18a, C'012 circuit 19a,
C'022 circuit 20a).

Next, when the occupant gets on and sits down, the occupant seating determination circuit of the occupant influence characteristic memory setting circuit 23 is based on signals from the seating sensor A24 inside the passenger seat 26 and the seating sensor B25 inside the driver seat 27. The occupant sitting state (for example, "driver only" or "driver, passenger occupant state") is determined by 23a, and the occupant influence characteristic CXmn (corresponding to the occupant sitting state is indicated to the CX memory setting circuit 23b. CX11, CX21, CX12, CX22) to CXmn
A signal is output so as to be set in the circuits (CX11 circuit 17b, CX21 circuit 18b, CX12 circuit 19b, CX22 circuit 20b), and these CX11 circuit 17b, CX21 circuit 18 are output.
b, a predetermined occupant influence characteristic (Xmn (CX11, CX21, CX12, CX22) is set in the CX12 circuit 19b and the CX22 circuit 20b.

Next, when the engine is started, engine vibration noise is transmitted through the mount or the like to become a vehicle interior sound.
Sounds of intake air and exhaust air are also propagated in the passenger compartment, and a predetermined vehicle body transmission characteristic C is put on the passenger seat 26, which is set to a position close to the ears of the passenger and a position of the driver seat 27 close to the ears of the driver. Reach the listening point. At the same time, for example, a signal obtained by shaping and processing a signal from an ignition pulse, a fuel injection pulse, a crank angle sensor (not shown), or the like, or a signal in which the load information of the engine is reflected in these signals is used. The primary source PSE having a high correlation with the related room vibration noise is input to the adaptive filters 11 and 12 and the speaker / microphone transfer characteristic estimation circuits 17, 18, 19, and 20.

The primary source PSE input to the adaptive filter 11 is a D / A converter and an amplifier (both are cancellation signals that are cancellation signals for canceling vibration noise by the convolution product sum with the filter coefficient). (Not shown), it is output as a canceling sound for the vibration noise at the listening point from the speaker 13 arranged in the front door or the like. At this time, the canceling sound output from the speaker 13 includes the transfer characteristic Cmn between the speaker and the microphone.
(C11, C21) is multiplied to reach the listening point. Similarly, the primary source PSE input to the adaptive filter 12 is given by the convolution product sum with the filter coefficient.
As a canceling signal which is a canceling sound signal for canceling the vibration noise, the vibration noise at the listening point is output from the speaker 14 provided on the front door or the like via a D / A converter and an amplifier (neither is shown). Is output as a canceling sound for. At this time, in the canceling sound output from the speaker 14, the speaker / microphone transfer characteristic Cmn (C12, C12,
C22) is added to reach the listening point.

Therefore, at the listening point, the engine-related vibration noise and the canceling noise interfere with each other to reduce the vibration noise, and at the same time, the error microphones 15 and 16 arranged near the listening point. As a result, the result of the interference between the vibration noise and the canceling noise is detected and sent to the LMS arithmetic circuits 21 and 22 as an error signal.

The primary source PSE input to the speaker / microphone transfer characteristic estimation circuit 17 is corrected by the C'011 circuit 17a and the CX11 circuit 17b and the speaker / microphone transfer characteristic estimation circuit 18 is corrected. The primary source PSE input to is the C'021 circuit 1
8a and the CX21 circuit 18b correct the L
It is sent to the MS arithmetic circuit 21. Then, in the LMS operation circuit 21, the filter correction amount is obtained from the error signal from the error microphones 15 and 16 and the primary source corrected by the speaker / microphone transfer characteristic estimation circuits 17 and 18, and the error microphones are obtained. An algorithm for updating the filter coefficient of the adaptive filter 11 is performed so that the error signals from 15 and 16 are minimized.

Further, the primary source PSE input to the speaker / microphone transfer characteristic estimating circuit 19 is corrected by the C'012 circuit 19a and the CX12 circuit 19b, and the speaker / microphone transfer characteristic estimating circuit 20 is corrected.
The primary source PSE input to is corrected by the C'022 circuit 20a and the CX22 circuit 20b and sent to the LMS operation circuit 22. Then, in the LMS arithmetic circuit 22, an instantaneous square error is obtained from the error signal from the error microphones 15 and 16 and the primary source corrected by the speaker / microphone transfer characteristic estimating circuits 19 and 20, and the error microphone is obtained. The adaptive filter 1 so that the error signals from 15 and 16 are minimized
An algorithm that updates the filter coefficient of 2 is performed.

As described above, in the present embodiment, system identification is performed at any time when there is no occupant, and the speaker / microphone transfer characteristics of the in-vehicle environment (in-vehicle temperature, in-vehicle humidity, change over time, arrangement of equipment, etc.) other than the occupant. The occupant's seating condition is stored in advance as the occupant's seating condition. Since the setting is performed, the occupant can eliminate the complicated work of setting the speaker / microphone transfer characteristic, and the random noise from the speaker when the speaker / microphone transfer characteristic is set is also generated by the passenger. Since it is carried out when there is no light, it does not make passengers feel uncomfortable.

Further, the system identification is performed at any time when there is no occupant, and it is set by obtaining the influence of the environment other than the occupant on the inside of the vehicle (temperature inside the vehicle, humidity inside the vehicle, change over time, arrangement of equipment, etc.) on the transmission characteristics between the speaker and the microphone. Therefore, it is possible to accurately obtain the speaker / microphone transmission characteristics that change depending on the in-vehicle environment, and it is possible to effectively and stably reduce noise.

In this embodiment, MEFX-LMS (Multiple Error Filtered X) in which the LMS algorithm of two error microphones and two speakers is expanded to multiple channels.
-A vehicle interior muffler noise reduction device using the LMS algorithm has been described, but it is also applicable to a vehicle interior muffler noise reduction device using another MEFX-LMS algorithm (for example, four error microphones, two speakers, etc.). In addition, the present invention is also applicable to a vehicle interior muffled noise reducing apparatus that uses a single-channel (one error microphone, one speaker) LMS algorithm.

[0035]

As described above, according to the present invention,
An unmanned state transfer characteristic setting means for setting the transfer characteristic between the canceling sound generating means and the error signal detecting means as an unmanned state transfer characteristic in advance in the absence of an occupant, and the seated state of the occupant gives the unmanned state transfer characteristic. Since the occupant influence characteristic memory setting means for storing the influence in advance and setting it as the occupant influence characteristic is provided, the occupant's seated state, vehicle interior temperature, vehicle interior humidity, aging change and It is possible to accurately obtain the transfer characteristic between the canceling sound generating means and the error signal detecting means that changes depending on the vehicle interior environment such as the arrangement of equipment, and it is possible to effectively and stably reduce fine noise.

[Brief description of drawings]

FIG. 1 is a system schematic view of a vehicle interior muffled noise reducing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic explanatory diagram of a case where a system for a vehicle interior muffled noise reducing apparatus according to an embodiment of the present invention is installed in a vehicle.

FIG. 3 is a conceptual diagram of initial setting of unmanned speaker / microphone transfer characteristics according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram of initial setting of occupant influence characteristics according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram of pre-use setting of unmanned speaker / microphone transfer characteristics according to an embodiment of the present invention.

FIG. 6 is a conceptual explanatory view of an unmanned speaker / microphone transmission characteristic and an occupant influence characteristic according to an embodiment of the present invention.

FIG. 7 is a conceptual diagram of setting a conventional speaker / microphone transfer characteristic.

[Explanation of symbols]

10 Car interior noise reduction device 11 Adaptive filter (cancellation signal synthesizing means) 12 Adaptive filter (cancellation signal synthesizing means) 13 Speaker (cancellation sound generating means) 14 Speaker (cancellation sound generating means) 15 Error microphone (error signal detection means) 16 error microphone (error signal detection means) 17 speaker / microphone transfer characteristic estimation circuit 17a C'011 circuit (unmanned state transfer characteristic setting means) 17b CX11 circuit (occupant influence characteristic memory setting means) 18 speaker / microphone transfer characteristic estimation Circuit 18a C'021 circuit (unmanned state transfer characteristic setting means) 18b CX21 circuit (passenger influence characteristic memory setting means) 19 Speaker / microphone transfer characteristic estimation circuit 19a C'012 circuit (unmanned state transfer characteristic setting means) 19b CX12 circuit (Passenger influence characteristic memory setting means) 20 Speaker / microphone transmission characteristics Estimating circuit 20a C'022 circuit (unmanned state transfer characteristic setting means) 20b CX22 circuit (passenger influence characteristic memory setting means) 21 LMS arithmetic circuit (cancel signal updating means) 22 LMS arithmetic circuit (cancel signal updating means) 23 Occupant influence characteristic Memory setting circuit (occupant influence characteristic memory setting means) 23a Occupant seating determination circuit 23b CX Memory setting circuit 24 Seating sensor A 25 Seating sensor B PSE Primary source (noise vibration source signal) RN Random noise C11 Speaker / microphone transfer characteristic C21 Speaker / Microphone transfer characteristics C12 Speaker / microphone transfer characteristics C22 Speaker / microphone transfer characteristics

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyuki Kondo 1-7-2 Nishishinjuku, Shinjuku-ku, Tokyo Fuji Heavy Industries Ltd. (72) Inventor Keitaro Yokota 1-2-7 Nishishinjuku, Shinjuku-ku, Tokyo Within Fuji Heavy Industries Ltd.

Claims (1)

[Claims] 1. A cancel signal synthesizing means for synthesizing a noise vibration source signal having a high correlation with engine vibration as a cancel signal by an adaptive filter, a canceling sound generating means for generating the cancel signal as a canceling sound for noise from a sound source, and a listening sound. Error signal detecting means for detecting a noise reduction state at a point as an error signal, and an unmanned state in which a transfer characteristic between the canceling sound generating means and the error signal detecting means is set as an unmanned state transfer characteristic in advance without an occupant. State transfer characteristic setting means, occupant influence characteristic memory setting means for storing in advance the influence of the seating state of the occupant on the unmanned state transfer characteristic and setting it as the occupant influence characteristic, and the noise vibration source signal as the unmanned state transfer characteristic. It is corrected with the occupant influence characteristic, and the adaptive filter is corrected based on the corrected noise and vibration source signal and the error signal. Cabin muffled sound reducing device characterized by comprising a cancel signal updating means for updating the filter coefficients of the terpolymer.