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JPH07281676

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DESCRIPTION JPH07281676
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for
example, a system for actively suppressing vibration of a tire, a suspension or the like during
traveling and vehicle interior noise generated by the vibration in a vehicle.
[0002]
2. Description of the Related Art Various types of noise such as engine noise, wind noise, road
noise and the like exist as noise generated during driving of a vehicle. Among these, the vibration
radiation noise generated by vibration of the tire and the suspension due to the unevenness of
the road surface during traveling is propagated to the vehicle compartment and vibrates a part of
the floor panel, and is generally called road noise. , Usually has a wide-band spectral distribution
of 30 to 300 (Hz).
[0003]
Such road noises also occur on relatively rough roads at speeds of 40 to 60 (km) on rough road
surfaces, and since this is an unpleasant sound for humans, various efforts have been made to
reduce this. Has been done.
[0004]
By the way, as a countermeasure for these noises, it is general to use a so-called "passive"
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method, such as a change in vehicle body structure design and a countermeasure using a sound
insulation material.
[0005]
On the other hand, an active noise control technology is attracting attention, which artificially
creates a secondary sound of opposite phase to the generated noise and muffles it in an "active"
manner.
[0006]
In particular, an example of a research report on a system that performs active noise reduction
using a secondary sound source for road noise can be found, for example, in the document
"Active Noise and Vibration Control within the Automobile, AM Mcdonald, et al, International
Symposium. on Active Control of Sound and Vibration, ASJ Proc, '91, Tokyo, April 9-11, 1991,
pp. 147-156.
[0007]
Among these, A. M. Mcdonald.
Et al., An active muffling system configured with two microphones and two speakers, using the
measurement output of two acceleration sensors mounted in close proximity to the wheel hub as
the vibration of the rear suspension as a reference signal. The system proposes and reports a
system that considerably reduces the noise level near 100 Hz at the rear seat position.
[0008]
The basic idea of such active noise control is old, and since the pioneering research conducted by
Lueg in the 1930s, research has been conducted by Olson, Conver, etc. in the 1950s. It has been
relatively recent that it has been applied to products.
This is largely due to the development of electronic devices capable of various controls, such as
digital signal processors (DSPs), but it can also be mentioned that technological advances in
software aspects such as theory of control algorithms have advanced.
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[0009]
The LMS adaptive control algorithm frequently used in active noise control technology is a
method organized by B. Widrow in the 1950s, and since this algorithm is versatile, recent
research on active noise control An example is almost using this control algorithm.
[0010]
This algorithm is described, for example, in the document "Signal Processing for Active ControlAdaptive Signal Processing: Hareo Hamada, International Symposium on Active Control of Sound
and Vibration, ASJ Proc, '91, Tokyo, April 9-11, 1991, pp. 33-44. Etc. ”.
In particular, multiple error filtered X LMS (abbreviated as "MEFX-LMS") as an algorithm for
silencing noise in a closed structure such as a car cabin by a plurality of microphones and a
plurality of speakers. An algorithm is mainly employed.
[0011]
FIG. 8 is an example of a block diagram of an adaptive control system based on the MEFX-LMS
algorithm.
[0012]
In this block diagram, K reference signals, L error signals, M output signals (secondary sound
output), etc. are input / output (here, K, L, M are natural numbers) .
[0013]
Now, the transfer function of the vibration noise transmission system of the vehicle is H, the
vibration signal detected by the acceleration sensor or the like is X, H, and the noise which
becomes an error signal (this noise is detected by a microphone) S Assuming that X and H are
vectors (one-row matrix) and S are matrices, the following relationship is established.
[0014]
In the adaptive control system shown in FIG. 7, X is used as a reference signal (the number of
elements of X is K), and the adaptive filter W operates so as to minimize the energy of the error
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signal E.
[0015]
That is, the following equation is established.
[0016]
However, specifically, D (vector of element number L) is the output sound of the speaker detected
by the microphone (secondary sound) and Y (vector of element number M) is It is a control
signal.
C is a space acoustic transfer function (which can be expressed by a matrix) from the speaker to
the microphone.
Note that the error signal actually detected includes the signal N other than S caused by X, but
this is a component that is noise to the control system and is input from outside the control
target.
[0017]
Adjustment of the adaptive filter W is performed momentarily using the MEFX-LMS algorithm.
Although this adjustment (meaning adjustment or updating of the coefficients of the digital filter)
is performed using the reference signal X and the error signal E, the reference signal X generates
a model function of C described above in the controller. It is filtered by C ^, which is commonly
referred to as filtered X.
[0018]
Each symbol in the block diagram shown in FIG. 8 indicates a physical quantity in the frequency
domain, and the computation in the frequency domain is realized by high-speed digital
computation using a DSP (digital signal processor) in an actual system. In the block diagram,
multiplications (products) can be expressed in the time domain by so-called convolution
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operations.
[0019]
The arithmetic expression is as follows.
[0020]
Here, ym (n) is an output signal of secondary sound control at the n-th sampling time for the mth speaker, and the reference signal x k (n) and the adaptive filter w m k (i) (i = 0 to I) It is given
by the convolution operation of -1).
Also, the adaptive filter wmk (i) that generates a signal to the m-th speaker based on the k-th
reference signal is updated by the following equation.
[0021]
Here, a model function of an acoustic transfer system between the m-th speaker and the l-th
microphone is represented by C ^ lm (j) by a digital FIR filter with J coefficients.
Also, rlmk (n) is filtered X.
[0022]
The above-mentioned adaptive filter update equation means that the squared sum value J of L
error signals at the n-th sampling time J = Σel (n) 2 (総 和 is the sum of l = 0 to L−1 In the
equation, the coefficients αmk and λmk are coefficients referred to as “convergence
coefficient” and “leaky parameter”, respectively.
[0023]
When the convergence coefficient αmk is large, the update fee for the adaptive filter wmk for
each update process becomes large, and a sound increase and an oscillation phenomenon are
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easily caused.
On the other hand, the leaky parameter λmk normally takes a value of 1 or less, and the
absolute value of each coefficient is reduced for each updating process of the adaptive filter.
[0024]
That is, although the leaky parameter works, the overgrowth of the adaptive filter can be
suppressed, but if the leaky parameter works too much compared to the update amount, the
adaptive filter can not grow and a sufficient control effect can not be obtained. .
In the ordinary LMS algorithm, it is general to set λmk = 1.
[0025]
Thus, the conventional active noise control system is realized using the adaptive system as
described above.
[0026]
By the way, in the above-mentioned active noise control system, of course, only noise can be
reduced by control, and vibration is not reduced but remains particularly sensitive to vibration.
For humans, they felt unnatural because they could not hear noise and could experience
vibrations.
[0027]
Here, the road noise and the like are vibration radiation noise generated as a result of road
surface vibration being propagated into the vehicle compartment and vibrating a part of the floor
panel, as described above.
[0028]
Therefore, if the vibration itself is reduced as a system for vibration suppression by exciting the
floor panel in the vicinity of the noise radiation source, the generation of noise can be
suppressed.
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[0029]
At this time, a vibration signal near the suspension may be used as the reference signal, and a
vibration signal of a body such as a floor panel may be used as the error signal.
However, due to the problem of causality and the generation of resonance, etc., the noise
component can not be completely removed.
Therefore, next, an adaptive filter using a vibration signal of the body as a reference signal and a
noise detected by a microphone disposed in the vehicle compartment as an error signal is
connected in cascade.
[0030]
Thus, the present invention was created to solve the above problems, and the problem to be
solved is to provide an active vibration noise control system for random vibration noise having a
broad spectrum such as road noise. , To simultaneously reduce vibration and noise.
[0031]
[Means for Solving the Problems] In order to solve the above problems, the following means can
be considered.
[0032]
That is, it is an apparatus for suppressing the vibration excited on the inner surface of the sealed
structure due to the vibration by the external vibration source and the noise generated inside the
sealed structure due to the vibration, and detecting the noise At least one or more noise detecting
means disposed inside the sealed structure to output a detection signal, and disposed in the
vicinity of a position where the vibration occurs to detect a vibration and output a detection
signal At least one or more first vibration detecting means, and at least one or more disposed
inside the sealed structure (inside surface position) near the generation position of the noise and
detecting the vibration and outputting a detection signal Second vibration detection means, at
least one or more vibration means provided in the vicinity of the inner surface position inside the
sealed structure, for vibrating the inner surface inside the sealed structure, and the noise
detection Means, No. , And as an input signal the output signal of the second vibration detection
unit is configured to include a vibration control circuit for generating a vibration control signal
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gives the to vibration means.
[0033]
Then, the vibration control circuit adjusts the phase and amplitude of the signal output from the
first vibration detection means so that the sum of squares of the output signals of the second
vibration detection means is minimized. To generate the first excitation control signal, and at the
same time, the signal output from the second vibration detection means so that the sum of
squares of the output signal of the noise detection means is minimized. Adjusting the phase and
amplitude to generate the second excitation control signal, and adding the first and second
excitation control signals as the excitation control signal It is an apparatus which supplies means.
[0034]
Also, the following means can be considered.
[0035]
That is, it is an apparatus for suppressing the vibration excited on the inner surface of the sealed
structure due to the vibration by the external vibration source and the noise generated inside the
sealed structure due to the vibration, and detecting the noise At least one or more noise detecting
means disposed inside the sealed structure to output a detection signal, and disposed in the
vicinity of a position where the vibration occurs to detect a vibration and output a detection
signal At least one or more first vibration detecting means, and at least one or more disposed
inside the sealed structure (inside surface position) near the generation position of the noise and
detecting the vibration and outputting a detection signal Second vibration detection means, at
least one or more vibration means provided in the vicinity of the inner surface position inside the
sealed structure, for vibrating the inner surface inside the sealed structure, and the sealed
structure Inside the body Excitation for providing the output means of at least one or more sound
output means for outputting an acoustic signal and the output signals of the noise detection
means, the first and second vibration detection means as input signals to the excitation means A
control signal and an excitation sound control circuit for generating a sound control signal to be
supplied to the sound output means are provided.
[0036]
Then, the excitation acoustic control circuit is configured to control the phase and the amplitude
of the signal output from the first vibration detection unit such that the sum of squares of the
output signal of the second vibration detection unit is minimized. The second vibration is
adjusted to generate the vibration control signal and supply it to the vibration means, and at the
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same time, the sum value of the square of the output signal of the noise detection means is
minimized. It is an apparatus which adjusts the phase and amplitude of the signal output from
the detection means, generates the sound control signal, and supplies it to the sound output
means.
[0037]
In the present invention, as described above, the noise detection means for detecting noise and
the one or more first sensors disposed in the vicinity of a position where vibration occurs, which
detects vibration and outputs a detection signal. Vibration detection means, one or more second
vibration detection means disposed inside the sealed structure near the generation position of
the noise and detecting the vibration, and in the vicinity of the inner surface position inside the
sealed structure Using the output signals of at least one or more vibration means, the noise
detection means, and the first and second vibration detection means for vibrating the inner
surface inside the sealed structure provided as input signals; And a vibration control circuit for
generating a vibration control signal to be supplied to the vibration means.
[0038]
Specifically, the excitation control circuit is configured to include first and second adaptive filters
that operate in accordance with a predetermined adaptive algorithm.
[0039]
The first adaptive filter uses the output signal of the first vibration detection means as a
reference signal and the output signal of the second vibration detection means as an error signal,
and the sum value of the squares of the error signals is a minimum. The excitation control signal
of the excitation means is generated and supplied to the excitation means, and the second
adaptive filter uses the error signal as a reference signal, and outputs the noise detection means.
A signal is used as an error signal of the second adaptive filter, and an excitation control signal of
the excitation means is generated so that the sum of squares of the error signal is minimized, and
the excitation control signal is A first adaptive filter supplies the excitation control signal in
addition to the excitation control signal supplied to the excitation unit.
[0040]
This makes it possible to realize a device that actively reduces noise and vibration.
[0041]
Embodiments of the present invention will be described below with reference to the drawings.
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[0042]
Although the following description assumes that the passenger compartment is in motion as an
example of the sealed structure, it goes without saying that the sealed structure is not limited to
this.
[0043]
FIG. 1 shows a configuration diagram of an example of an active noise control device for
reducing noise generated due to vibration of a vehicle due to the unevenness of the road surface,
which is called road noise, among noises in a vehicle interior.
[0044]
First, the components of this system will be described.
[0045]
The acceleration sensor 1 is a means for detecting an output according to vibration, and can be
realized by, for example, a G sensor of a piezoelectric element type or a capacitance type.
The acceleration sensor 1 is mounted on, for example, a front wheel suspension, and an output
signal is used as a reference signal of the adaptive filter as described later.
In general, it is preferable to provide a plurality.
[0046]
The acceleration sensor 10 can be realized by the same configuration as the acceleration sensor
1 and is a means having the same function.
However, the acceleration sensor 10 is disposed on the body floor as shown in FIG.
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In general, it is preferable to arrange a plurality.
[0047]
The microphone 2 is a means for detecting at least one or more microphones disposed in the
vehicle compartment and detecting noise in the vehicle compartment, and may be realized using
a commercially available microphone for audio.
[0048]
The exciter 3 is means for outputting an excitation waveform according to a given control signal,
and is used to suppress noise and vibration as will be described later.
It is sufficient to arrange at least one or more.
[0049]
The vibration exciter 3 may be, for example, one using an electromagnetic voice coil or an
electrostrictive element such as PZT.
In the case of the electrostrictive element, since the element itself expands and contracts with
respect to the applied electrical signal, the mounting portion of the electrostrictive element is
applied by applying a periodic voltage, for example, by applying the electrical signal. It becomes
a means to vibrate periodically.
[0050]
The controller 4 controls the low pass filter 41 for filtering the signals 101 and 107, the A / D
converter 42 for converting the filtered analog signal into a digital signal, the low pass filter 43
for filtering the signal 103, and the filtered analog signal A / D converter 44 for converting into a
digital signal, microprocessor 40, D / A converter 45 for converting a digital signal into an analog
signal, low pass filter 46 for filtering an analog signal, and a signal to be given to the vibrator 3 It
is configured to have a power amplifier 5.
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[0051]
The microprocessor 40 realizes the adaptive filter 1 (201) and the adaptive filter 2 (202), and
has a function of inputting a predetermined signal and outputting the predetermined signal.
Although not shown, the microprocessor 40 includes a RAM and a ROM, and predetermined
processing is performed in accordance with a program stored in the ROM.
In addition, calculation results and the like are stored in the RAM.
Of course, when the functions of the RAM are substituted by various registers provided in the
microprocessor 40 itself, the RAM may not necessarily be provided.
When the microprocessor 40 is formed into an ASIC, if the ROM is built in, the ROM may not
necessarily be provided outside the microprocessor 40.
[0052]
Now, the operation of the present system will be described below.
[0053]
When vibration of the suspension occurs due to traveling, it is detected by the acceleration
sensor 1, and an output signal of the acceleration sensor 1 is input to the controller 4 as a sensor
detection signal 101.
The vibration of the suspension is transmitted to the body floor, and the vibration of the floor
generates noise in the passenger compartment.
[0054]
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The vibration of the floor is detected by the acceleration sensor 10, and the noise generated in
the passenger compartment is detected by the microphone 2.
A signal detected by the acceleration sensor 10 is supplied as a sensor signal 107, and a signal
detected by the microphone 2 is supplied as a sound pressure signal 103 to the controller 4.
[0055]
Next, the sensor signals 101 and 107 and the sound pressure signal 103 are converted to digital
signals 102, 108 and 104 through low pass filters (LPFs) 41 and 43 and A / D converters 42 and
44, respectively. It is input to the processor 40.
[0056]
The microprocessor 40 first uses the signal 102 obtained by digitizing the output signal 101 of
the first acceleration sensor 1 as a reference signal, and convolutes with the first adaptive digital
filter 201 according to the above-mentioned "filtered XLMS algorithm". The calculation generates
a first exciter control signal for controlling the exciter 3.
[0057]
Here, the filter coefficient of the first adaptive digital filter 201 uses the signal 108 obtained by
digitizing the output signal 102 of the second acceleration sensor 10 as an error signal, and the
sum of squares of the error signal 108 is minimized. Adaptively updated from time to time to
generate a first exciter control signal.
[0058]
At the same time, the microprocessor 40 uses the signal 108 obtained by digitizing the signal
107 as a reference signal, and generates a second exciter control signal by convolution with the
second adaptive digital filter 202.
Finally, the filter coefficients of the filter 202 generate a second exciter control signal such that
the sum of squares of the digital signal 104 obtained by digitizing the sound pressure signal 103
is minimized. Adaptively updated every moment.
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[0059]
Then, the addition signal 105 of the first exciter control signal and the second exciter control
signal is output as a control signal, and the D / A converter 45, the low pass filter (LPF) 46, the
power amplifier The signal is converted into a drive signal 106 of the exciter 3 through 5 and
supplied to the exciter 3.
[0060]
Therefore, the vibrator 3 controls the vibration generated by the acceleration sensor 1 of the
front wheel suspension transmitted to the body to be minimized at the position of the
acceleration sensor 10, and at the same time The noise generated by the vibration is controlled
to be minimized at the position of the microphone 2.
[0061]
Next, FIG. 2 is a block diagram of the system shown in FIG.
[0062]
However, although in FIG. 2 a one-input one-output system is used to simplify the description, in
practice, as described in the prior art, adaptive filter control with multiple inputs and multiple
outputs is general.
Further, signals, transfer functions and the like in the figure indicate quantities in the frequency
domain.
Therefore, the product in the block diagram is represented by a convolution operation in the time
domain.
[0063]
Now, in FIG. 2, the output signal 101 of the acceleration sensor 1 mounted on the suspension is
taken as a reference signal X.
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X passes through the vibration transfer system H1 to become a vibration signal X1, and is
detected as an output signal of the acceleration sensor 10 mounted on the body floor, that is, as a
signal 107 (it is the signal 108 that is digitized). Further, it passes through the vehicle interior
space acoustic transmission system H 2 to become a noise signal X 2, which is detected by the
microphone 2 as a signal 103.
[0064]
In FIG. 2, C1 represents a transfer function from the exciter 3 to the sensor 10, and C2 ^
represents a transfer function C2 (not shown) from the exciter 3 to the microphone 2 (not
shown). It is clear from the block diagram that C2 = C1 · H2.
[0065]
In addition, N1 and N2 are (noise) components of vibration and noise generated by causes other
than the vibration of the suspension, and are elements not to be controlled, and therefore will not
be considered in the following description.
[0066]
On the other hand, in the adaptive control system 1, the exciter control signal Y1 is generated
from the reference signal X and the adaptive filter W1 (201).
[0067]
The adaptive filter W1 uses the error signal E1 = X1 + D1 and the filtered X signal (C1 ^ .X) to
generate I.I. Update by the MS algorithm (the algorithm may use the one described in the prior
art) so that the squared value of E1 (usually, the sum value of the squared value at a
predetermined time) is minimized Be done.
Here, D1 represents a control vibration signal provided by the vibrator 3.
[0068]
On the other hand, in the adaptive control system 2, the error signal E1 of the adaptive control
system 1 is used as a reference signal, and the adaptive filter W2 (by 202) generates an exciter
control signal Y2.
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[0069]
The adaptive filter W2 uses the error signal E2 = X2 and the filtered X signal (C2 ^ · E1), and
according to the LMS algorithm, the squared value of E2 (usually, the sum value of the squared
value at a predetermined time) Is updated to be minimized.
[0070]
Further, the addition signal Y = Y1 + Y2 is output as the control signal 105 of the vibrator 3,
passes through the transfer function C1, becomes D1, and is added to X1.
Then, the operations of the adaptive filters W1 and W2 suppress and control the vibration X1
and the noise X2 so as to be minimized.
[0071]
Here, although the control parameters used for adaptive control systems 1 and 2, that is, the
values of the aforementioned convergence coefficient α and leaky parameter λ are set
separately, basically, adaptive control system 1 is the first. It is desirable that it be set to adapt to
the optimal condition (ie, convergence is fast).
The reason is that the error signal E1 of the adaptive control system 1 is used as a reference
signal in the adaptive control system 2, but E1 is influenced by the output of the adaptive control
system 1 during the progress of the adaptive control of the adaptive control system 1. Because
they receive a large amount of
[0072]
Next, FIG. 3 shows a configuration diagram of another embodiment (second embodiment)
according to the present invention, which is a system in which emphasis is placed on suppression
of vehicle interior noise.
[0073]
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The system configuration is not significantly different from that shown in FIG. 1, but instead of
the acceleration sensor 10 mounted on the body floor, a (first) microphone 20 is mounted
adjacent to the body floor, and further The feature is that this output signal is input to a low pass
filter (LPF) 43.
[0074]
In addition, the same components as those in FIG. 1 are denoted by the same reference numerals,
and descriptions thereof will be omitted because they will be redundantly described.
[0075]
The first microphone 20 is closer to the noise generation position, and is configured to be able to
detect noise earlier in time than the conventional microphone 2 (referred to as (second
microphone) in this embodiment).
[0076]
Therefore, the noise signal 110 detected by the first microphone 20 is input to the LPF 43
together with the noise signal 103 detected by the second microphone 2, and the digital signals
114 and 104 are respectively transmitted through the A / D converter 44. And input to the
microprocessor 40.
[0077]
The adaptive filter 201 then detects the vibration signal 101 (specifically, the signal 102 filtered
by the LPF 41 and digitized by the A / D converter 42) as a reference signal and the noise signal
110 detected by the first microphone 20. The oscillator control signal is generated such that the
square value of the error signal is minimized with the error signal as the error signal.
On the other hand, the other adaptive filter 202 uses the noise signal 110 (specifically, the signal
114 filtered by the LPF 43 and digitized by the A / D converter 44) as a reference signal and the
noise signal 103 as an error signal. An exciter control signal is generated such that the square
value of the error signal is minimized.
Then, the exciter control signals generated by the adaptive filters 201 and 202 are added, and
this (106) is supplied to the exciter 3.
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[0078]
Therefore, also in the present embodiment, since the suppression of the vehicle interior noise
due to the excitation of the vibration exciter is performed in two stages, a large noise suppression
effect can be obtained.
The block diagram for the present embodiment is the same as the block diagram of FIG. 2, so the
description of the block diagram is omitted here.
[0079]
By the way, in the system as shown in FIG. 1, the vibration that is the source of the noise is
suppressed before the noise control in the latter stage.
Therefore, if the arrangement and performance of the sensor, the exciter, and the control ability
of the controller are sufficient, the vibration control in the previous stage should remove
components that would be generally noise.
However, the vibration frequency of the residual vibration component is the car's vibration
frequency, etc., when the vibration amplitude of excitation is very large during rough road
traveling, etc. and the body vibration can not be completely eliminated even by the maximum
output capability of the exciter. For example, when the sound mode matches the sound mode
unique to the room, the vibration may be greatly amplified, which may cause a problem that
noise suppression control can not be performed sufficiently.
[0080]
Even in such a case, a speaker is provided separately from the exciter so that noise can be
sufficiently suppressed, vibration control is performed by the exciter, and noise suppression is
performed by the speaker and the actuator. A configuration that defines
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FIG. 4 shows a block diagram of an embodiment of such a system.
[0081]
First, the system configuration in FIG. 4 will be described.
[0082]
The same reference numerals as in FIG. 1 denote the same parts as those in FIG. 1, and a
description thereof will be omitted because they will be redundantly described.
[0083]
The difference is that a D / A converter 47, a low pass filter (LPF) 4 and an amplifier 6 are newly
connected to the microprocessor 40.
Then, the signal from the amplifier 6 is supplied to the newly provided speaker 30.
[0084]
The microprocessor 40 shown in FIG. 4 generates the digital signal 105 by the convolution
operation of the vibration signal 101 and the adaptive filter 201, and generates the digital signal
105 through the D / A converter 45, the low pass filter (LPF) 46 and the power amplifier 5. The
excitation signal 106 is supplied to the exciter 3.
[0085]
On the other hand, the digital signal 115 is generated by the convolution operation of the noise
signal 107 and the adaptive filter 202, and the acoustic signal 116 is supplied to the speaker 30
via the D / A converter 47, the LPF 48 and the power amplifier 6.
[0086]
The adaptive filter 201 performs an update process for performing adaptive control using the
signal 108 obtained from the acceleration sensor 10 as the error signal and the noise signal 104
obtained from the microphone 2 as the error signal.
03-05-2019
19
[0087]
FIG. 5 is a block diagram of the system of FIG.
[0088]
Here, C2 is a transfer function from the speaker 30 to the microphone 2, which is different from
the case of FIG.
H1 and H2 are the same as in FIG.
[0089]
As shown in FIG. 5, the adaptive control system 1 generates an exciter control signal Y1 from the
reference signal X and the adaptive filter W1 (201), and Y1 passes through C1 to become a
control vibration D1.
[0090]
C1 represents the transfer function from the exciter 3 to the sensor 10, and C1 ^ is a model of
C1.
[0091]
Further, the adaptive control system 2 uses the error signal E1 of the adaptive control system 1
as a reference signal, and generates a speaker control signal Y2 from the reference signal and the
adaptive filter W2 (202).
The speaker control signal Y2 then passes through to become an acoustic signal D2.
[0092]
Here, W1 is updated using the error signal E1 = X1 + D1 and the filtered X signal (C1 ^ · X), and
the adaptive filter W2 outputs the error signal E2 = X2 + D2 and the filtered X signal (C2 ^ · E1).
Using, the LMS algorithm is updated to minimize E2's squared value (generally, the sum of E2's
03-05-2019
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squared value for a predetermined time to be minimized).
[0093]
Then, the outputs of the exciter and the speaker are controlled by the functions of the adaptive
filters W1 and W2 so that the vibration X1 and the noise X2 are minimized.
[0094]
By the way, especially when physical quantities such as random vibration and noise are to be
controlled, the problem is the time until the original vibration is detected and control is
performed at the evaluation point position of vibration and noise. Constraints.
[0095]
That is, while the vibration is transmitted from the suspension to the body and the noise is
transmitted from the body panel to the microphone position, the sensor signal is detected, the
controller arithmetic processing, and the output to the vibrator (speaker) A series of controls,
including the supply of signals, must be completed, and the controller is burdened with such a
series of processes.
[0096]
Therefore, the signal used as the reference signal is the output signal of the acceleration sensor
10 (or the microphone 20) attached to the body floor, with only the vibration signal 101 (102)
from the acceleration sensor 1 attached to the suspension. By setting the error signal of the
adaptive filter 201 and the output signal of the microphone 2 mounted in the vehicle
compartment as the error signal of the adaptive filter 202, at least control time for noise control
can be reduced. .
[0097]
6 and 7 are block diagrams according to an embodiment in which such a situation is taken into
consideration.
[0098]
In addition, since the whole system configuration | structure figure is the same as FIG.1, FIG3 and
FIG.4, description of system configuration is abbreviate | omitted.
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[0099]
In FIG. 6, a reference signal X is, for example, an output signal of the acceleration sensor 1
mounted on a suspension.
X passes through the vibration transmission system H1 to become a vibration signal X1, and is
detected as, for example, an output signal of the acceleration sensor 10 mounted on the body
floor.
[0100]
Furthermore, for example, a noise signal X2 obtained by passing through the vehicle interior
space acoustic transmission system H2 is detected by the microphone 2.
[0101]
C1 represents, for example, a transfer function from the vibrator to the acceleration sensor 10,
and C2 represents, for example, a transfer function from the vibrator to the microphone.
[0102]
First, in FIG. 6, the adaptive control system 1 generates the exciter control signal Y1 from the
reference signal X and the adaptive filter W1 (201), and the adaptive control system 2 generates
the reference signal X and the adaptive filter W2 ( An exciter control signal Y2 is generated from
202).
[0103]
Then, the addition signal Y = Y1 + Y2 is output to the vibrator as a control signal, passes through
the transfer function C1 to be D1, and is added to the vibration signal X1.
[0104]
Here, the adaptive filter W1 of the adaptive control system 1 is updated using the error signal E1
= X1 + D1 and the filtered X signal (C1 ^ · X) by the LMS algorithm so that the square value of E1
becomes minimum. .
[0105]
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22
On the other hand, the adaptive filter W2 of the adaptive control system 2 is updated by the LMS
algorithm using the error signal E2 = X2 and the filtered X signal (C2 ^ · X) so that the square
value of E2 becomes minimum.
However, “C2 ^” is a function that models C2 = C1 · H2.
[0106]
FIG. 7 shows an example of the configuration of another block diagram.
[0107]
In FIG. 7, the reference signal X is, for example, an output signal of the acceleration sensor 1
mounted on the suspension.
X passes through the vibration transmission system H1 to become a vibration signal X1, and is
detected as, for example, an output signal of the acceleration sensor 10 mounted on the body
floor.
[0108]
Furthermore, for example, the noise signal X2 obtained by passing through the vehicle interior
space acoustic transmission system H2 is detected by the microphone.
[0109]
C1 represents, for example, a transfer function from the vibrator to the acceleration sensor 10,
and C2 represents, for example, a transfer function from the vibrator to the microphone.
[0110]
Although the reference signal X is used to generate the exciter control signals Y1 and Y2, the
output Y1 becomes D1 through C1 and becomes the vibration signal X1, the output Y2 becomes
D2 through C2 and the noise signal X2 , Are added respectively.
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23
[0111]
Then, the updating process of the adaptive filter W1 (201) and the adaptive filter W2 (202) is
performed as error signals E1 = X1 + D1, E2 = X2 + D2, and filtered X signals “C1 ^ · X”, “A”
respectively. Using C2 ^ · X ′ ′, the LMS algorithm is performed to minimize the square value
of the error signals E1 and E2 (or to minimize the total value of the square value within a
predetermined time). It will be.
[0112]
As described above, according to the present invention, in a closed structure space such as a
vehicle interior while traveling, vibration generated based on external vibration and vibration
noise generated based on such vibration frequently occur. By adaptively controlling both
vibration and noise in stages, stable control can be performed to suppress both, and as a result,
both vibration and noise are greatly reduced, which is comfortable. It is possible to realize a
system that provides an efficient sealed structure space.
[0113]
According to the present invention, stable control of random vibration and noise having a wideband spectral distribution can be performed by separately executing control for suppressing
noise and vibration. Has the advantage of being able to
[0114]
Brief description of the drawings
[0115]
1 is a block diagram of an example of an apparatus according to the present invention.
[0116]
2 is a control block diagram of an example of the apparatus according to the present invention.
[0117]
3 is a block diagram of an example of an apparatus according to the present invention.
[0118]
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4 is a block diagram of an example of an apparatus according to the present invention.
[0119]
5 is a control block diagram of an example of an apparatus according to the present invention.
[0120]
6 is a control block diagram of an example of the apparatus according to the present invention.
[0121]
7 is a control block diagram of an example of the apparatus according to the present invention.
[0122]
8 is an explanatory view of a conventional active noise control device.
[0123]
Explanation of sign
[0124]
DESCRIPTION OF SYMBOLS 1 ... Acceleration sensor, 2 ... Microphone, 3 ... Vibrator, 4 ...
Controller, 5 ... Amplifier, 41 ... Low pass filter, 42 ... A / D converter, 43 ... Low pass filter, 44 ... A
/ D converter, 45 ... D / A converter, 46 ... low pass filter, 101 ... sensor detection signal
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