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DESCRIPTION JP2000214861

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DESCRIPTION JP2000214861
[0001]
The present invention relates to interference between noise and vibration transmitted from a
noise source such as a vehicle engine or the like or a vibration source to a compartment or a
vehicle body with a control sound or a control vibration generated from an actuator or the like.
The present invention relates to an active noise and vibration control apparatus adapted to
reduce, in particular, to reduce the possibility that control sound or control vibration emitted
from a control sound source or a control vibration source falls into a cyclic fluctuation state. It is.
[0002]
2. Description of the Related Art A prior art of this type is disclosed, for example, in Japanese
Patent Laid-Open No. 5-40488. That is, in the conventional active noise control device disclosed
in the above publication, the drive signal for driving the control sound source is generated using
the reference signal representing the noise generation state and the digital filter with variable
filter coefficient. The major feature is that it is designed to be able to effectively regulate the
phenomenon (beat) in which the filter coefficients of the digital filter periodically fluctuate.
[0003]
This will be specifically described by taking the case where the digital filter is composed of two
filter coefficients W0 and W1 as an example. First, the filter coefficients W0 and W1 excluding
direct current components are multiplied and multiplied The DC component is further extracted
from the combined result, it is determined that the beat is detected when the absolute value of
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the extracted DC component exceeds a predetermined threshold, and the process for regulating
the beat is executed. It was like that.
[0004]
Then, when a state in which the filter coefficient fluctuates periodically is detected, for example,
among the coefficients included in the update formula of the digital filter, a suppression
coefficient having an effect of reducing the filter coefficient (closer to the origin) A measure can
be taken to suppress periodic fluctuation by changing (for example, the divergence suppression
coefficient) in the direction in which the suppression action becomes stronger.
[0005]
Furthermore, such periodic fluctuations are often phenomena dependent on the frequency of
noise and vibration, and periodic fluctuations occur in one frequency band, but not in other
frequency bands. There is.
Therefore, the suppression coefficient as described above is provided for each of a plurality of
frequency bands, and when periodic fluctuation is detected, the suppression coefficient for a
frequency band including the frequency of noise or vibration when it is detected. It is more
desirable to change only in the direction in which the suppression action is intensified, since it is
also possible to avoid reducing the vibration and noise reduction action in the frequency band in
which no periodic fluctuation occurs.
[0006]
However, according to the research conducted by the inventors of the present invention, when
the above suppression coefficients are provided for each of a plurality of frequency bands and
control is performed to individually change them. On the contrary, it has been found that
periodic fluctuation may be caused, which may cause discomfort to users and the like.
[0007]
That is, for example, considering a situation in which the suppression coefficient of a certain
frequency band A is large (the suppression action is strong) and the suppression coefficient of
another frequency band B adjacent to the frequency band A is small (the suppression action is
small) If the frequency of the frequency band moves back and forth in the frequency bands A and
B, the effect of reducing the filter coefficient is strong when in the frequency band A, and
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conversely, the function is weak when in the frequency band B, so noise or noise It is conceivable
that the amplitude of the control sound and the control vibration periodically fluctuate as the
frequency of the vibration moves back and forth in the frequency bands A and B.
[0008]
Then, for example, when a periodic fluctuation state is detected, in a device including a process
for increasing the suppression coefficient to suppress it, the frequency of the noise or vibration
as described above is a frequency. The periodic fluctuation that occurs as the bands A and B
move back and forth is detected, and the suppression coefficient is further increased. Eventually,
the suppression coefficient of the frequency band A and the suppression coefficient of the
frequency band B reach the maximum value. It will reach.
[0009]
In addition, even if the periodic fluctuation state is not detected and appropriately dealt with, for
example, the divergence or the tendency thereof is detected, and the suppression coefficient is
changed for each frequency band according to the result. In the apparatus, when the values of
the suppression coefficients in adjacent frequency bands are different, if noise and vibration
frequencies come and go in those frequency bands, periodic fluctuation is also caused. There is a
possibility that the user etc. feels uncomfortable.
[0010]
The present invention has been made in view of such technical problems, and it is an object of
the present invention to provide an active noise and vibration control apparatus capable of
further reducing the possibility of being in a periodic fluctuation state.
[0011]
SUMMARY OF THE INVENTION In order to achieve the above object, the invention according to
claim 1 executes noise or vibration reduction processing using an adaptive digital filter whose
filter coefficients are updated according to an adaptive algorithm. In addition, the update
equation of the filter coefficient includes a suppression coefficient having the function of
suppressing an increase in the filter coefficient of the adaptive digital filter, and the suppression
coefficient is set for each of the plurality of frequency bands of noise or vibration. In the active
noise and vibration control apparatus, the suppression coefficient for the frequency band
including the frequency of the noise or vibration is changed in the direction in which the action
becomes stronger when a predetermined condition is satisfied. When the suppression coefficient
for one frequency band is changed in the direction in which the action becomes stronger in
response to satisfaction of the predetermined condition, The suppression factor for other
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frequency bands adjacent to the frequency band, provided the suppression coefficient adjusting
means for changing the direction in which the effect becomes stronger.
[0012]
In order to achieve the above object, the invention according to claim 2 is a control sound source
or control vibration source capable of generating a control sound or control vibration that
interferes with noise or vibration emitted from a noise source or vibration source, and the noise
or Reference signal generation means for detecting the generation state of vibration and
outputting as a reference signal, residual noise detection means or residual vibration detection
means for detecting noise or vibration after the interference and outputting as residual noise
signal or residual vibration signal, Active control means for generating and outputting a drive
signal for driving the control sound source or the control vibration source so that noise or
vibration after the interference is reduced according to an adaptive algorithm based on a
reference signal and the residual noise signal or the residual vibration signal. And the active
control means comprises an adaptive digital filter having variable filter coefficients, and a filter
coefficient of the adaptive digital filter And a drive signal generation unit configured to generate
the drive signal based on the reference signal and the adaptive digital filter, wherein the update
formula includes the adaptive digital filter. And the suppression coefficient is set for each of a
plurality of frequency bands of the noise or vibration, and the noise is included if a
predetermined condition is satisfied. Alternatively, in the active noise and vibration control
apparatus in which the suppression coefficient for the frequency band including the frequency of
vibration is changed in the direction in which the action becomes stronger, one of the two
according to the satisfaction of the predetermined condition. When the suppression coefficient
for the frequency band is changed in the direction in which the action becomes stronger, for the
other frequency band adjacent to the one frequency band The suppression factor, provided
suppression coefficient adjusting means for changing a direction in which the effect becomes
stronger.
[0013]
The invention according to claim 3 is the periodic noise fluctuation detection apparatus
according to claim 2, wherein a periodic fluctuation state of the drive signal or the residual noise
signal or the residual vibration signal is detected. A state detection unit is provided, and the
predetermined condition is that a periodic fluctuation state of the drive signal or the residual
noise signal or the residual vibration signal is detected.
[0014]
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The invention according to claim 4 is the active noise and vibration control device according to
the invention according to claim 2, further comprising: a divergence detection means for
detecting a divergence or divergence tendency of control, wherein the predetermined condition
is that of the control It was assumed that the divergence or the divergence tendency was
detected.
The invention according to claim 5 is the active noise and vibration control device according to
the invention according to claims 1 to 4, wherein the suppression coefficient for one frequency
band is the above according to satisfaction of the predetermined condition. When the action is
changed in the direction in which the action is intensified, the suppression coefficient adjusting
means sets the suppression coefficient for another frequency band adjacent to the one frequency
band to the same value as the suppression coefficient for the one frequency band. I made it to.
[0015]
Further, in the invention according to claim 6, in the active noise and vibration control device
according to the invention according to claim 3, the suppression coefficient for one frequency
band is the above according to the detection of the periodic fluctuation state. In the case where
the action is changed in the direction in which the action is intensified, the frequency of the noise
or vibration is a plurality of frequency bands while the periodic fluctuation state detection means
determines whether or not the periodic fluctuation state is present. When changing over the
range, the suppression coefficient adjusting means makes the respective suppression coefficients
for the plurality of frequency bands equal to the value of the suppression coefficient with the
strongest effect among them.
[0016]
In order to achieve the above object, the invention according to claim 7 executes noise or
vibration reduction processing using an adaptive digital filter in which filter coefficients are
updated according to an adaptive algorithm, and an update equation for the filter coefficients is
used. A suppression coefficient having the function of suppressing an increase in the filter
coefficient of the adaptive digital filter, the suppression coefficient being set for each of a
plurality of frequency bands of noise or vibration, and a predetermined condition is satisfied In
the active noise and vibration control apparatus, the suppression coefficient for the frequency
band including the frequency of the noise or vibration is changed in the direction in which the
action becomes stronger, the frequency of the noise or vibration is more than one. The value of
the suppression coefficient of each of the plurality of frequency bands is the most powerful of
Provided suppression coefficient adjusting means for aligning the value of the suppression
coefficient.
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[0017]
In order to achieve the above object, the invention according to claim 8 is a control sound source
or control vibration source capable of generating a control sound or control vibration that
interferes with noise or vibration emitted from a noise source or vibration source, and Reference
signal generation means for detecting a noise or vibration generation state and outputting as a
reference signal, and residual noise detection means or residual vibration detection means for
detecting noise or vibration after the interference and outputting as residual noise signal or
residual vibration signal Active control means for generating and outputting a drive signal for
driving the control sound source or the control vibration source so that noise or vibration after
the interference is reduced according to an adaptive algorithm based on the reference signal and
the residual noise signal or the residual vibration signal And the active control means includes an
adaptive digital filter with variable filter coefficients, and filter coefficients of the adaptive digital
filter. A filter coefficient updating unit that updates according to an update equation based on a
response algorithm, and a drive signal generation unit that generates the drive signal based on
the reference signal and the adaptive digital filter, and the update equation includes the adaptive
digital A suppression coefficient having an effect of suppressing an increase in the filter
coefficient of the filter is included, and the suppression coefficient is set for each of a plurality of
frequency bands of noise or vibration, and when a predetermined condition is satisfied, In an
active noise and vibration control apparatus configured to change the suppression coefficient for
a frequency band including noise or vibration frequency in a direction in which the action
becomes stronger, the noise or vibration frequency is a plurality of frequency bands. When going
back and forth, the value of the suppression coefficient of each of the plurality of frequency
bands is suppressed most strongly among them. Provided suppression coefficient adjusting
means for aligning the value of the coefficient.
[0018]
The invention according to claim 9 is the periodic noise fluctuation detection apparatus
according to claim 8, wherein a periodic fluctuation state of the drive signal or the residual noise
signal or the residual vibration signal is detected. A state detection unit is provided, and the
predetermined condition is that a periodic fluctuation state of the drive signal or the residual
noise signal or the residual vibration signal is detected.
[0019]
The invention according to claim 10, in the active noise and vibration control device according to
claim 8, further comprises: a divergence detection means for detecting a divergence or a
divergence tendency of control, wherein the predetermined condition is that of the control It was
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assumed that the divergence or the divergence tendency was detected.
Here, in the invention according to claims 1 and 2, the suppression coefficient for one frequency
band is changed in such a direction that the effect of suppressing the increase of the filter
coefficient becomes stronger in response to satisfaction of the predetermined condition. After
that, when the frequency of noise or vibration is in the one frequency band, the filter coefficient
is prevented from increasing, the level of the drive signal becomes relatively low, and the control
sound or control vibration becomes Becomes relatively smaller.
[0020]
On the other hand, the suppression coefficient adjustment means changes the suppression
coefficient for the other frequency band adjacent to one frequency band in the direction in which
the above-mentioned action becomes stronger.
Therefore, thereafter, even when the frequency of noise or vibration is in the other frequency
band, the filter coefficient is prevented from increasing, the level of the drive signal becomes
relatively low, and the control sound and The control vibration is relatively small.
[0021]
As a result, even if the frequencies of noise and vibration move back and forth between the one
frequency band and the other frequency bands, it is difficult for the control sound and the
control vibration to periodically fluctuate.
In particular, the fact that the suppression coefficient for one frequency band is changed in the
above direction means that control in the vicinity of that one frequency band is often unstable, so
it was adjacent to that one frequency band By forcibly changing the suppression coefficients for
other frequency bands as described above, it is possible to avoid the beating state with a
relatively high probability.
[0022]
As a specific method of changing the suppression coefficients for other frequency bands in the
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direction in which the above action becomes stronger, for example, a method of matching the
values of the suppression coefficients as in the invention according to claim 5 may be used. Or a
method in which the suppression factor for another frequency band is in a fixed ratio to the
suppression factor for one frequency band (for example, the former is 50% of the latter). Good.
[0023]
In the invention according to claim 3, when the periodically fluctuating state is detected by the
periodic fluctuating state detecting means, the suppression coefficient for the frequency band
including the frequency of the noise or vibration at that time has the above function strongly.
And the suppression coefficients for other frequency bands adjacent to that one frequency band
are also changed in the same direction.
For this reason, a situation that promotes periodic fluctuation in the vicinity of a relatively
unstable frequency band where periodic fluctuation has occurred is avoided with a relatively
high probability.
[0024]
In the invention according to claim 4, when the diverging detection means detects the diverging
or diverging tendency of the control, the above-described effect is enhanced by the suppression
coefficient for the frequency band including the frequency of the noise or vibration at that time.
The direction is changed, and the suppression coefficients for other frequency bands adjacent to
the one frequency band are also changed in the same direction.
For this reason, it is possible to avoid, with a relatively high probability, a situation where
periodic fluctuation is also caused in the vicinity of a relatively unstable frequency band where
control divergence occurs.
[0025]
In the invention according to claim 6, the frequency of noise or vibration changes over a plurality
of frequency bands while the cyclic fluctuation state detection means determines whether or not
the cyclic fluctuation state is present. If the suppression coefficients for one frequency band are
changed, it is considered that periodic fluctuation is likely to occur if the suppression coefficients
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of the plurality of frequency bands do not match. Since the values of the suppression coefficients
for the frequency band are made uniform, the possibility of causing periodic fluctuation can be
reduced.
[0026]
In the invention according to claims 7 and 8, when the frequency of noise or vibration travels a
plurality of frequency bands, more specifically, when the frequency of noise or vibration travels a
plurality of frequency bands in a short cycle. If the suppression coefficients of the plurality of
frequency bands do not match, it is considered that periodic fluctuation is likely to occur, and the
values of the suppression coefficients for the plurality of frequency bands are equalized, which
may cause periodic fluctuation. Can be reduced.
[0027]
In the invention according to claim 9, when the periodic fluctuation state detection means detects
the periodic fluctuation state, the suppression coefficient for the frequency band including the
frequency of the noise or vibration at that time has the above function strongly. In the case
where the noise or vibration frequency moves back and forth in a plurality of frequency bands,
the suppression coefficient adjusting means aligns the suppression coefficients for the plurality
of frequency bands.
For this reason, a situation that promotes periodic fluctuation in the vicinity of a relatively
unstable frequency band where periodic fluctuation has occurred is avoided with a relatively
high probability.
[0028]
In the invention according to claim 10, when the divergence detection means detects the
divergence of control or the tendency thereof, the suppression coefficient for the frequency band
including the frequency of the noise or vibration at that time becomes stronger Although the
direction is changed, when the frequency of noise or vibration travels a plurality of frequency
bands, the suppression coefficient adjusting means aligns the suppression coefficients for the
plurality of frequency bands.
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For this reason, it is possible to avoid, with a relatively high probability, a situation where
periodic fluctuation is also caused in the vicinity of a relatively unstable frequency band where
control divergence occurs.
[0029]
As described above, according to the present invention, the suppression coefficients are provided
for each of a plurality of noise or vibration frequency bands, and the suppression coefficients are
individually determined according to whether or not predetermined conditions are satisfied.
Since the suppression coefficient adjustment means is provided while changing, there is an effect
that the possibility that the control sound and the control vibration periodically fluctuate can be
reduced.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be
described below with reference to the drawings.
1 to 6 are views showing an embodiment of the present invention, and FIG. 1 is a schematic side
view of a vehicle to which an active vibration control device is applied, which is an embodiment
of the active noise and vibration control device according to the present invention. FIG.
[0031]
First, the configuration will be described. A laterally mounted engine 17 is supported by a vehicle
body 18 composed of a suspension member and the like via an active engine mount 20 disposed
at the rear in the longitudinal direction of the vehicle body.
In practice, in addition to the active engine mount 20, a plurality of engine mounts that generate
a passive supporting force according to the relative displacement between the engine 17 and the
vehicle body 18 intervene between the engine 17 and the vehicle body 18 ing.
As a passive engine mount, for example, a conventional engine mount that supports a load with a
rubber-like elastic body, or a known fluid-sealed mount in which a fluid is enclosed in a rubber-
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like elastic body so as to generate damping force. An insulator etc. are applicable.
[0032]
FIG. 2 is a plan view showing the upper structure of the active engine mount 20 connected via a
bracket (not shown) fixed to the engine 17, and projects upward from the engine side connecting
member 30. The upper end portion is fixed to the engine 17 by inserting the two connection
bolts 30a from the lower side into the insertion holes of the above-mentioned bracket and
screwing the nuts.
Further, reference numeral 60 is a rebound restricting member, and the rebound restricting
member 60 is orthogonal to a line connecting between the two connecting bolts 30a and extends
in an arch shape above the engine side connecting member 30. It is fixed to the case 43 and is
located above the rebound stopper 31 made of a rubber elastic body fixed to the upper surface of
the engine side connecting member 30.
[0033]
FIG. 3 shows the internal structure of the active engine mount 20 shown by the arrow sectional
view of FIG. 2, and the AA arrow sectional view along the line connecting between the two
connecting bolts 30a of FIG. The B-B arrow cross-section in the direction perpendicular to the
line connecting the two connecting bolts 30a of FIG. 2 is shown on the right side with the axis P1
of FIG. 3 (hereinafter referred to as the mount axis) as a boundary. The third mount axis P1 is
shown on the right side as a boundary.
[0034]
The active engine mount 20 incorporates mount components such as an outer cylinder 34, an
intermediate cylinder 36, an orifice component 37, and a support elastic body 32 in a device case
43, and in the lower part of these mount components A device incorporating an electromagnetic
actuator 52 for displacing the elastically supported movable member 78 in a direction in which
the volume of the fluid chamber 84 changes while forming a part, and a load sensor 64 for
detecting a vibration state of a not-shown vehicle member In the engine-side connecting member
30 described above, the lower end peripheral portion 30g is formed to be rounded, and the first
hole 30c is formed at a position along the mount axis P1. ing.
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Further, a head 30 d of the connecting bolt 30 a which is inserted into the engine connecting
member 30 from the lower side and is directed upward protrudes from the lower surface of the
engine side connecting member 30.
Here, the outer peripheral edge portion of the head 30d is formed to be rounded.
[0035]
In addition, a hollow cylindrical body 30 b having an inverted trapezoidal cross section is fixed to
the lower surface of the engine side connecting member 30.
In the hollow cylindrical body 30b, a second hole 30e is formed at a position close to the
connection bolt 30a, and a third hole 30f is formed in the lower surface along the mount axis P1.
In addition, the hole is not formed in the position away from the connection bolt 30a of this
hollow cylindrical body 30b.
[0036]
A rubber support elastic body 32 is fixed on the lower surface side of the engine side connecting
member 30 by vulcanization bonding so as to cover the inside of the hollow cylindrical body 30b
and the lower side of the engine side connecting member 30. .
That is, although this support elastic body 32 is a rubber elastic body having a diameter
expanded downward from the engine side connecting member 30 side, a hollow portion 32a
having a cross-sectional mountain shape is formed on the inner surface, The outer peripheral
surface of the support elastic body 32 at a portion away from the connection bolt 30a is
continuous with the rebound stopper 31 while covering the outer peripheral portion of the
engine side connection member 30, as shown on the left side of FIG.
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12
On the other hand, as shown in the right side of FIG. 3, the support elastic body 32 in the vicinity
of the connecting bolt 30a is formed with a covering portion 32b covering the entire area of the
head 30d of the connecting bolt 30a. The outer periphery at the lower position has a shape that
is greatly recessed inward (hereinafter, referred to as a recess outer peripheral portion indicated
by reference numeral 32c). Further, the inner surface of the support elastic body 32 facing the
recess outer peripheral portion 32c while forming the hollow portion 32a described above is also
formed in a largely expanded shape inside (hereinafter referred to as a bulge inner peripheral
portion indicated by reference numeral 32d) ). The thickness of the portion of the support elastic
body 32 in the vicinity of the connection bolt 30a is the thickness of the portion away from the
connection bolt 30a by providing the swelling inner periphery 32d facing the recess outer
periphery 32c. It is set approximately the same as the thickness.
[0037]
The lower end portion of the thin-walled support elastic body 32 is bonded by vulcanization
bonding to the inner peripheral surface of the intermediate cylindrical body 36 whose mount
axis P1 faces the vibrator supporting direction coaxially with the hollow cylindrical body 30b.
The intermediate cylindrical body 36 is a member in which a small diameter cylindrical portion
36c is continuously formed between the upper end cylindrical portion 36a and the lower end
cylindrical portion 36b having the same outer peripheral diameter, and an annular recess is
provided on the outer circumference. Although not shown, an opening is formed in the small
diameter cylindrical portion 36c, and the inside and the outside of the intermediate cylindrical
body 36 communicate with each other through the opening.
[0038]
An outer cylinder 34 is fitted on the outer side of the intermediate cylinder 36, and the outer
cylinder 34 has an inner peripheral diameter equal to the outer peripheral diameters of the
upper end cylindrical portion 36a and the lower end cylindrical portion 36b of the intermediate
cylindrical body 36. It is a cylindrical member of which the length in the direction is set to the
same dimension as that of the intermediate cylinder 36. Further, an opening 34a is formed in the
outer cylinder 34, and the outer periphery of a diaphragm 42 made of a thin elastic film made of
rubber is connected to the opening edge of the opening 34a to close the opening 34a. It bulges
toward the inside of the outer cylinder 34.
[0039]
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13
And if the outer cylinder 34 of the said structure is externally fitted to the intermediate cylinder
36 so that an annular recessed part may be enclosed, an annular space will be formed in the
circumferential direction between the outer cylinder 34 and the intermediate cylinder 36, 42 is
arranged in a bulging state. A cylindrical orifice component 37 is fitted inside the intermediate
cylinder 36. The orifice forming member 37 includes a minimum diameter cylindrical portion
37a formed in a smaller diameter than the small diameter cylindrical portion 36c of the
intermediate cylindrical body 36, and the upper annular portion is directed radially outward at
the upper and lower end portions of the minimum diameter cylindrical portion 37a. An annular
space is provided between the intermediate cylinder 36 and a position surrounded by the
smallest diameter cylindrical portion 37a, the upper and lower annular portions 37b and 37c. In
addition, a second opening 37d is formed in part of the minimum diameter cylindrical portion
37a. Here, the upper annular portion 37b is located below the support elastic body 32, but as
shown on the right side of FIG. 2, it is located below the support elastic body 32 close to the
connection bolt 30a. The upper annular portion 37b1 has a thin wall and is provided with a
recess, and is opposed at a position apart from the swelling inner peripheral portion 32d of the
support elastic body 32.
[0040]
In the device case 43, an upper end caulking portion 43a having a circular opening smaller than
the outer diameter of the upper end cylindrical portion 36a is formed at the upper end portion,
and the shape of the case main body continuous with the upper end caulking portion 43a A
member having an inner circumferential diameter the same size as the outer circumferential
diameter of the outer cylinder 34 and continuing to the lower end opening (a shape in which the
lower end opening is indicated by a broken line in FIG. 2); After completion, by caulking the
lower end opening inward in the radial direction, a caulked portion shown by a solid line in FIG. 2
is formed.
[0041]
Then, an outer cylinder 34 in which the support elastic body 32, the intermediate cylinder 36,
the orifice component 37, and the diaphragm 42 are integrated is fitted into the inside from the
lower end opening of the device case 43, and outside the lower surface of the upper crimped
portion 43a. When the upper end portions of the cylinder 34 and the intermediate cylinder 36
are brought into contact with each other, they are disposed at the upper portion in the device
case 43.
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At this time, an air chamber 42c is defined in a portion surrounded by the inner peripheral
surface of the device case 43 and the diaphragm 42, and an air hole 43a is formed at a position
facing the air chamber 42c. The air chamber 42c is in communication with the atmosphere via
43a.
[0042]
A cylindrical spacer 70 is fitted in the lower part in the device case 43, the movable member 78
is disposed in the upper part in the spacer 70, and the electromagnetic actuator 52 is disposed in
the lower part in the spacer 70. . The spacer 70 is a substantially cylindrical diaphragm 70c
formed of a cylindrical upper cylindrical body 70a, a cylindrical lower cylindrical body 70b, and
a rubber thin-film elastic body bonded by vulcanization between upper and lower end portions of
these cylindrical bodies. And consists of.
[0043]
The electromagnetic actuator 52 has a yoke 52a of an external appearance cylindrical shape, an
annular excitation coil 52b disposed on the upper end face side of the yoke 52a, and a
permanent magnet having a magnetic pole fixed vertically to the upper surface center of the
yoke 52a. And 52c. The yoke 52a is formed of an annular first yoke member 53a and a second
yoke member 53b in which a permanent magnet 52c is fixed to the central cylindrical portion.
[0044]
The diaphragm 70c between the upper and lower cylindrical bodies 70a and 70b bulges toward
a recess 52d formed on the outer periphery of the yoke 52a. Further, a load sensor 64 is
interposed between the lower surface of the yoke 52 a and the lid member 62 provided with the
vehicle body side connection bolt 60 in order to detect residual vibration necessary for vibration
reduction control. As the load sensor 64, a piezoelectric element, a magnetostrictive element, a
strain gauge or the like can be applied, and the detection result of this sensor is supplied to the
controller 25 as a residual vibration signal e as shown in FIG. There is.
[0045]
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On the other hand, above the electromagnetic actuator 52, a seal ring 72 for fixing the seal
member, a support ring 74 for supporting the free end of an outer peripheral portion of a plate
spring 82 described later from below, permanent magnets 52c of the electromagnetic actuator
52 and A gap holding ring 76 for setting a gap H between the movable members 78 is disposed.
The outer peripheral diameters of the seal ring 72, the support ring 74, and the gap holding ring
76 are set to the same dimensions as the inner peripheral diameter of the upper cylindrical body
70a of the spacer 70 described above, and the upper cylinder protrudes upward from the yoke
52a. The seal ring 72, the support ring 74 and the gap retaining ring 76 are all fitted in the body
70a. A movable member 78 is disposed on the inner side of the seal ring 72, the support ring 74
and the gap holding ring 76 so as to be vertically displaceable.
[0046]
The movable member 78 is a member constituted by an external appearance disk-like partition
forming member 78A and a magnetic path forming member 78B formed in a disk shape having a
larger diameter than the partition forming member 78A, and is far from the electromagnetic
actuator 52. The bolt hole 80a is formed in the axial center of the partition wall forming member
78A located on the opposite side, and the movable member bolt 80 penetrating the magnetic
path forming member 78B close to the electromagnetic actuator 52 is screwed into the bolt hole
80a. The member 78A and the magnetic path forming member 78B are integrally connected.
[0047]
A ring-shaped continuous constriction 79 is defined between the partition forming member 78A
and the magnetic path forming member 78B, and a leaf spring 82 for elastically supporting the
movable member 78 is accommodated in the constriction 79. ing.
That is, the plate spring 82 is a disk-shaped member having a hole formed at the center, and the
inner peripheral portion of the plate spring 82 is supported at its free end from the lower side of
the back surface center of the partition forming member 78A. The spring support portion 74a of
the support ring 74 supports the outer peripheral portion of the outer peripheral portion 82
from the lower side at its free end, whereby the movable member 78 is elastically supported by
the device case 43 via a plate spring 82.
[0048]
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The partition wall forming member 78A is a member in which the thickness of the partition wall
80c facing the fluid chamber 84 is reduced, and an annular rib 80b protruding upward from the
outer periphery of the partition wall 80c is formed. A fluid chamber 84 is formed by the upper
surface of the partition forming member 78A, the lower surface of the support elastic body 32,
and the inner peripheral surface of the orifice component 37, and the fluid is sealed in the fluid
chamber 84.
[0049]
Further, in order to prevent the fluid from leaking from the fluid chamber 84 to the side of the
constricted portion 79 accommodating the plate spring 82, rubber-like elasticity is provided
between the outer periphery of the partition forming member 78A and the inner periphery of the
seal ring 72. A ring-shaped seal member 86 made of a body is fixed, and elastic deformation of
the seal member 86 allows relative displacement of the movable member 78 in the vertical
direction with respect to the seal ring 72 and the device case 43.
[0050]
Next, the vibration input damping action of the active engine mount 20 of the present
embodiment will be briefly described.
In the active engine mount 20 according to the present embodiment, the hollow portion 32a of
the support elastic body 32 and the axial central space of the orifice component 37 communicate
with each other, and the axial central space of the orifice component 37 and the orifice
component 37 and the intermediate cylinder An annular space between them and 36
communicate with each other through the second opening 37d, and a space where the annular
space and the diaphragm 42 bulge out communicate with each other through an opening formed
in the intermediate cylinder 36. A fluid such as ethylene glycol is sealed in the communication
passage from the hollow portion 32a of the support elastic body 32 to the space where the
diaphragm 42 bulges.
[0051]
When the communication passage from the hollow portion 32a of the support elastic body 32 to
10-04-2019
17
the annular space between the orifice component 37 and the intermediate cylinder 36 is the
main fluid chamber 84, the vicinity of the opening formed in the intermediate cylinder 36 is A
fluid resonance system is formed, which is an orifice, and a region surrounded by the diaphragm
42 facing the opening is a sub fluid chamber. The characteristics of the fluid resonance system,
that is, the mass of the fluid in the orifice, the expansion direction spring of the support elastic
body 32, and the expansion direction spring of the diaphragm 42, are determined when idle
vibration occurs while the vehicle is stopped. When the engine mounts 20A and 20B are excited
at 30 Hz, they are adjusted to exhibit a high dynamic spring constant and a high damping force.
[0052]
On the other hand, the exciting coil 52b of the electromagnetic actuator 52 generates a
predetermined electromagnetic force in accordance with a drive signal y which is a current
supplied from the controller 25 through, for example, a harness. The controller 25 includes a
microcomputer, necessary interface circuits, A / D converters, D / A converters, amplifiers,
storage media such as ROMs, RAMs, and the like, and can reduce vibrations generated by the
engine 17. The drive signal y to the active engine mount 20 is generated and output so that a
proper supporting force is generated in the active engine mount 20.
[0053]
Further, as described above, the load sensor 64 is built in the active engine mount 20, detects the
vibration state of the vehicle body 18 in the form of load, and outputs it as the residual vibration
signal e. The signal is supplied to the controller 25 through a harness, for example, as a signal
representing a later vibration. Here, for example, in the case of a reciprocating four-cylinder
engine, the idle vibration and the booming noise vibration generated by the engine 17 are mainly
caused by the transmission of the engine vibration of the engine rotation secondary component
to the vehicle body 18, If the drive signal y is generated and output in synchronization with the
rotational secondary component, it is possible to reduce the vehicle body side vibration.
Therefore, in the present embodiment, an impulse signal synchronized with the rotation of the
crankshaft of the engine 17 (for example, in the case of a reciprocating four-cylinder engine, one
for each rotation of the crankshaft by 180 degrees) is generated and the reference signal x is
generated. , And the reference signal x is supplied to the controller 25.
[0054]
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18
Then, based on the residual vibration signal e and the reference signal x supplied, the controller
25 is a synchronous Filtered-X LMS algorithm (hereinafter, referred to as SFX algorithm) which is
one of adaptive algorithms. Is executed to calculate a drive signal y for the active engine mount
20, and the drive signal y is output to the active engine mount 20.
[0055]
Specifically, the controller 25 includes an adaptive digital filter W that has a variable filter
coefficient Wi (i = 0, 1, 2,..., I-1: I is the number of taps), and the latest reference signal x The
filter coefficients Wi of the adaptive digital filter W are sequentially output as the drive signal y
at predetermined sampling clock intervals from the time when the signal is input, while the
adaptive digital filter W is output based on the reference signal x and the residual vibration
signal e. A process of appropriately updating the filter coefficient Wi of is performed.
[0056]
However, in this embodiment, the following equation (1) is used as an evaluation function in the
SFX algorithm.
Jm = {e (n)} 2 + β {y (n)} 2 (1) That is, in the LMS algorithm, the filter coefficient Wi is updated in
the direction in which the evaluation function Jm becomes smaller, so As apparent from the
contents of the right side of the above equation (1), the filter coefficient Wi is such that the
square value of the residual vibration signal e becomes smaller and the value obtained by
multiplying the square value of the drive signal y by β becomes smaller. It will be updated one
by one. And, β is a coefficient called a divergence suppression coefficient, and the drive signal y
tends to be smaller as the divergence suppression coefficient β becomes larger. That is, the
divergence suppression coefficient β has an effect of suppressing the divergence of control.
[0057]
Then, assuming that the convergence coefficient is α and the update equation of the filter
coefficient Wi is obtained based on the evaluation function Jm represented by the above equation
(1), the following equation (2) is obtained. Wi (n + 1) = Wi (n) + 2 α RT e (n)-2 β α y (n) Then,
let "2 α" in this equation (2) be a new convergence coefficient α, and "2 β α" a new one.
Assuming that the divergence suppression coefficient βk, the updating equation of the filter
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19
coefficient Wi of the adaptive digital filter W is as shown in the following equation (3).
[0058]
Wi (n + 1) = Wi (n) + αRT e (n)-βky (n) (3) where the terms with (n) and (n + 1) are the values at
sampling time n, n + 1, Represents that. Also, theoretically, the reference signal RT for updating is
filtered by the transfer function filter C ^ that models the transfer function C between the
electromagnetic actuator 52 of the active engine mount 20 and the load sensor 64. However,
since the magnitude of the reference signal x is “1”, the sampling time n of the impulse
response waveform when the impulse response of the transfer function filter C ^ is generated in
synchronization with the reference signal x one after another Corresponds to the sum in
[0059]
Also, theoretically, the reference signal x is filtered by the adaptive digital filter W to generate the
drive signal y, but since the magnitude of the reference signal x is “1”, the filter coefficients Wi
are sequentially ordered Even if it is output as the drive signal y, the same result as the drive
signal y is obtained as the result of the filtering process. The controller 25 further includes a shift
position detection signal S representing the shift position from the automatic transmission 28
attached to the engine 30, and an engine rotation speed detection signal N from an engine
rotation speed sensor 29 for detecting the rotation speed of the engine 30. Is to be supplied.
[0060]
Then, the controller 25 detects a state in which the drive signal y fluctuates periodically in
parallel with the vibration reduction processing using the adaptive digital filter W as described
above (periodical fluctuation state detection processing). When this is detected, processing for
suppressing the periodic fluctuation state (periodic fluctuation state suppression processing) is
performed.
[0061]
That is, in the periodic fluctuation state detection processing, the amplitude My of the drive
signal y can be obtained, and is it in a state where the drive signal y is periodically fluctuated
based on the change width of the amplitude My? It is judged whether or not it is.
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20
In this embodiment, since the synchronous Filtered-X LMS algorithm is adopted, the amplitude
My of the drive signal y is the maximum value and the minimum value of the filter coefficient Wi
output within one period of the reference signal x. It can be determined by halving the difference
from the value.
[0062]
Further, during execution of the periodic fluctuation state detection processing, the shift position
detection signal S and the engine rotational speed detection signal N are monitored, and the
automatic transmission 28 based on the shift position detection signal S. If it is confirmed that
the shift position of the engine has changed, and if it is confirmed that the engine speed has
fluctuated large (for example, ± 100 rpm or more) based on the engine speed detection signal N,
periodic fluctuation The state detection process is interrupted midway, and the process is reexecuted from the beginning.
[0063]
Furthermore, when the monotonous increase is detected as described above during execution of
the periodic fluctuation state detection process, the timer measures time from the time when the
monotonous increase is detected, and the measurement time T2 is a predetermined time. Even if
Tth2 (for example, 2 seconds) is reached, if the monotonous decrease is not detected, the
periodic fluctuation state detection processing is interrupted midway and the processing is reexecuted from the beginning.
[0064]
Then, in the periodic fluctuation state detection processing, when the periodic fluctuation state of
the drive signal y is detected, the rotational speed N of the engine 17 at that time (corresponding
to the frequency of the vibration) as cyclic fluctuation state suppression processing. A process is
performed to increase the divergence suppression coefficient βk corresponding to the rotational
speed band including.
That is, in the present embodiment, the rotation speed N of the engine 17 is divided into a
plurality of K bands, and a plurality of divergence suppression coefficients whose values are
variable stepwise corresponding to each of the K bands. .beta.k (k = 1, 2,..., K).
10-04-2019
21
Then, when the filter coefficient Wi is updated according to the above equation (3), the
divergence suppression coefficient βk for a band including the engine speed N at that time is
used, and the periodic fluctuation state detection is performed. When the cyclic fluctuation state
is detected by the processing, the value of the divergence suppression coefficient βk for the
rotational speed band including the engine rotational speed N at that time is increased by one
step.
[0065]
Furthermore, in the present embodiment, when it is confirmed that the engine speed N is
changed over the plurality of rotation speed bands during execution of the periodic fluctuation
state detection processing, the plurality of rotation speeds are detected. The values of the
divergence suppression coefficients βk corresponding to the respective bands are made to be
the largest among the divergence suppression coefficients βk. Next, the operation of the present
embodiment will be described.
[0066]
When the ignition switch is turned on and the power is supplied, the controller 25 can execute
predetermined arithmetic processing, output the drive signal y to the electromagnetic actuator
52, and reduce the vibration to the active engine mount 20. Active support will be generated. The
drive signal y for the active engine mount 20 is the filter coefficient Wi of the adaptive digital
filter W, and the adaptive digital filter W is based on the residual vibration signal e which is the
load applied to the active engine mount 20 (3). Since it is updated according to the equation, if
the filter coefficient Wi converges to the optimum value or approaches the optimum value
sufficiently after a certain time has passed since the control was started, the active engine mount
20 from the engine 17 side. The vibration transmitted to the side of the vehicle body 18 through
this is canceled by the active supporting force generated by the active engine mount 20, and the
vibration level on the side of the vehicle body 18 near the position where the active engine
mount 20 is disposed is reduced. Is taken.
[0067]
The above is the operation of the vibration reduction processing that is executed when the
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22
vehicle is traveling or the like. On the other hand, in the controller 25, processing as shown in
FIG. 4 is executed substantially in parallel with the vibration reduction processing. First, in step
101, the shift position detection signal S and the engine speed signal N are read, and then the
step At 102, the shift position which is known from the shift position detection signal S is stored
as the reference shift position S0, and the engine rotational speed which is known from the
engine rotational speed signal N is stored as the reference engine rotational speed N0.
[0068]
Next, the process proceeds to step 103, where the engine speed is determined based on the
engine speed at that time, and the engine speed band is used as a variable to store the
determined engine speed band. It is designed to write information to the table. The contents of
the table are reset at the end of the process of FIG. 4 as described later, and the information to be
written is only one bit because it is whether or not the rotational speed band has passed.
[0069]
Next, in step 104, the amplitude My of the drive signal y is calculated, then in step 105, the latest
shift position detection signal S and engine speed signal N are read, and then in step 106, The
latest shift position and engine speed obtained from each signal read in step 105 are compared
with the reference shift position S0 and reference engine speed N0 stored in step 102, and at
least one of the shift position and engine speed is It is determined whether or not there is a
change from the time when the process of FIG. 4 this time is started. Note that, in the
determination processing of step 106, it is determined that the engine rotation speed has not
changed in the case of a change of, for example, about 100 rpm, instead of determining an exact
match regarding the engine rotation speed.
[0070]
Then, if the determination in step 106 is “YES”, the process proceeds to step 107, and the
flags Finc and Fdec used in the process of FIG. 4, the information in the table, the maximum value
Mymax, and the minimum value Mymin are reset. Then, the processing of FIG. 4 this time is
ended. The flags Finc and Fdec and the maximum value Mymax are reset to 0, the minimum
value Mymin is reset to a relatively large value as the amplitude My, and all the information in
the table is cleared. The reason for executing the process of step 106 is that if at least one of the
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23
shift position and the engine speed is changing and the process after step 108 is executed, the
periodic fluctuation of the drive signal y is erroneously detected. Because it is likely to end up, it
is to avoid it.
[0071]
If the determination in step 106 is "NO", the process proceeds to step 108, and information is
written in the above-described table in order to store the rotational speed band including the
engine rotational speed N read in step 105. The engine speed band including the latest engine
speed N read in step 105 is the engine speed band including the past engine speed N read in step
102, or the processes after step 104 are repeatedly executed. After that, if it is the same as the
rotational speed band including the past engine rotational speed N read in step 105 before the
previous time, new information is not written to the table.
[0072]
Next, the process proceeds to step 109, where it is determined whether the flag Finc is set to 1. If
the determination is "NO", the process proceeds to step 110 where the flag Fdec is set to 1 or
not. Is determined. The flag Finc is a flag that is set to 1 when it is detected that the amplitude
My of the drive signal y has exceeded the predetermined threshold Mth2 from the minimum
value Mymin, as described later. Is a flag that is set to 1 when it is detected that the amplitude
My of the drive signal y decreases from the maximum value Mymax beyond a predetermined
threshold value Mth1, as described later.
[0073]
Therefore, when the processes of steps 109 and 110 are initially executed in the process of FIG.
4 this time, the determinations of these steps 109 and 110 are both “NO”, so the process
proceeds to step 111. Then, in step 111, the latest amplitude My is compared with the amplitude
My1 obtained one before to determine whether the amplitude My has increased from the
previous state. Here, if it is determined that the amplitude My is increasing, the process proceeds
to step 112, and it is determined whether the latest amplitude My is larger than the maximum
value Mymax. When Step 112 is initially executed in the process of FIG. At step 113, the current
amplitude My is substituted for the maximum value Mymax, then the routine proceeds to step
114 where the timer T4 is cleared and started. The timer T4 is a timer for measuring an elapsed
10-04-2019
24
time from when the maximum value Mymax is detected, and is cleared and started each time the
step 113 is executed.
[0074]
Next, the process proceeds to step 115. If the determination in step 112 is "NO", the process
proceeds from step 112 directly to step 115. Then, at step 115, it is judged whether or not the
difference (My-Mymin) between the current amplitude My and the minimum value Mymin stored
at that time exceeds a predetermined threshold value Mth2 (> 0). Do. Since the minimum value
Mymin is set to a relatively large value when step 115 is initially executed in the process of FIG.
4, the determination in step 115 is “NO”, and the process returns to step 104. However, if the
process is repeatedly executed and the determination in step 115 is "YES", the process proceeds
to step 116 and the flag Finc is set to 1.
[0075]
On the other hand, if the determination in step 111 is "NO", that is, if it is determined that the
amplitude My is decreasing, the process proceeds to step 117, and it is determined whether the
latest amplitude My is smaller than the minimum value Mymin. Determine Since the minimum
value Mymin is set to a relatively large value when the step 117 is initially executed in the
process of FIG. 4, the determination in the step 117 is “YES”, and the process proceeds to the
step 118 and the minimum Substituting the current amplitude My into the value Mymin, then the
routine proceeds to step 119, where the timer T3 is cleared and started. The timer T3 is a timer
for measuring an elapsed time from when the maximum value Mymin is detected, and is cleared
and started each time the step 118 is executed.
[0076]
Then, it proceeds to step 120. When the determination in step 117 is "NO", the process directly
proceeds from step 117 to step 120. Then, in step 120, it is determined whether or not the
difference (Mymax-My) between the maximum value Mymax stored at that time and the current
amplitude My exceeds a predetermined threshold value Mth1 (> 0). Do. Since the maximum value
Mymax is set to 0 when the step 120 is initially executed in the process of FIG. 4, the
determination in the step 120 is “NO”, and the process returns to the step 104. However, if the
process is repeatedly executed and the determination in step 120 is "YES", the process proceeds
10-04-2019
25
to step 121, where the flag Fdec is set to 1.
[0077]
Since both determinations in steps 109 and 110 remain “NO” until one determination in steps
115 and 120 is “YES”, the processing in step 111 and subsequent steps is repeatedly
executed. Further, if at least one of the shift position and the engine speed changes while the
process of FIG. 4 is being performed, the determination of step 106 becomes “YES” and the
process proceeds to step 107. The process of FIG. 4 ends.
[0078]
However, a decrease in the amplitude My beyond the threshold Mth1 is detected without a
change in the shift position or the engine speed (the determination at step 120 becomes
“YES”), or the threshold of the amplitude My is detected. When an increase beyond the value
Mth2 is detected (the determination in step 115 is "YES"), the determination in step 109 or step
110 is "YES".
[0079]
Then, if the determination in step 109 is "YES" (Finc = 1), it is immediately after a large increase
in the amplitude My of the drive signal y is detected, so to determine the periodic fluctuation
state of the drive signal y. Next, the process proceeds to step 122 to execute processing for
confirming a significant decrease in the amplitude My.
In step 122, the amplitude My is compared with the maximum value Mymax to determine
whether the increasing tendency of the amplitude My has ended. If the determination in step 122
is "YES", although a large increase in the amplitude My is confirmed in step 115, it can be
determined that the amplitude My is also increasing thereafter, so the process proceeds to step
123, Update the maximum value Mymax. Then, the process proceeds to step 124, where it is
determined whether the value of the timer T3 exceeds a predetermined time Tth3. Since the
timer T3 is a timer that is cleared and started each time the minimum value Tymin is updated, it
represents an elapsed time from the time when the minimum value Tymin stored at that time is
detected. When the elapsed time is relatively long, the possibility of false detection is high even if
the periodic fluctuation state of the drive signal y is detected. Therefore, if the determination in
step 124 is "YES", the process proceeds to step 107, and the current process of FIG. 4 is forcibly
10-04-2019
26
ended. If the determination in step 124 is "NO", the process returns to step 104.
[0080]
On the other hand, if the determination in step 122 is "NO", it can be determined that the
amplitude My has turned to a decrease after a significant increase in the amplitude My has been
confirmed in the step 115, so the width of the decrease is cyclically fluctuating To step 125 to
determine whether or not it is a substantial one. At step 125, the same judgment processing as at
step 120 is executed. If the judgment is "NO", it is judged that the significant decrease of the
amplitude My can not be confirmed, and the routine proceeds to step 124.
[0081]
However, if the determination in step 125 is "YES", it can be determined that a significant
decrease in the amplitude My is subsequently confirmed after a significant increase in the
amplitude My has been confirmed, whereby the drive signal y It can be determined that a
periodic fluctuation state has been detected. Therefore, the process proceeds to step 126, and
after the process for eliminating or suppressing the periodic fluctuation state is executed, the
process proceeds to step 107, and the process of FIG. 4 is ended. The details of the process in
step 126 will be described later.
[0082]
If the determination in step 109 is “NO” and the determination in step 110 is “YES” (flag
Fdec = 1), the processes of steps 127 to 130 are performed. That is, at step 127, the amplitude
My is compared with the minimum value Mymin to determine whether the decreasing tendency
of the amplitude My has ended. If the determination in step 127 is "YES", although a significant
decrease in the amplitude My is confirmed in step 120, it can be determined that the amplitude
My is also decreasing thereafter, so the process proceeds to step 128, Update the minimum value
Mymin. Then, the process proceeds to step 129, where it is determined whether the value of the
timer T4 exceeds a predetermined time Tth4. Since the timer T4 is a timer that is cleared and
started each time the maximum value Tymax is updated, it represents an elapsed time since the
maximum value Tymax stored at that time is detected. When the elapsed time is relatively long,
the possibility of false detection is high even if the periodic fluctuation state of the drive signal y
is detected. Therefore, if the determination in step 129 is "YES", the process proceeds to step
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27
107, and the current process of FIG. 4 is forcibly ended. If the determination in step 129 is "NO",
the process returns to step 104.
[0083]
On the other hand, if the determination at step 127 is "NO", it can be determined that the
amplitude My has turned to an increase after the significant decrease of the amplitude My has
been confirmed at step 120, so the width of the increase is cyclically fluctuating To step 130 to
determine whether or not it is a substantial one. In step 130, the same determination processing
as step 115 is executed. If the determination is "NO", it is determined that a significant increase
in the amplitude My has not been confirmed, and the process proceeds to step 129.
[0084]
However, if the determination in step 130 is "YES", it can be determined that a large increase in
the amplitude My is subsequently confirmed after a large decrease in the amplitude My has been
confirmed, whereby the driving signal y It can be determined that a periodic fluctuation state has
been detected. Therefore, the process proceeds to step 126, and after the process for eliminating
or suppressing the periodic fluctuation state is executed, the process proceeds to step 107, and
the process of FIG. 4 is ended.
[0085]
FIG. 6 is a diagram showing how the amplitude My of the drive signal y changes, and in the case
of this example, since the amplitude My gradually increases until time t1, the determination in
step 111 is The determination in step 112 is also “YES”, the processing in steps 113 and 114
is executed, and the maximum value Mymax is updated each time. Then, since the amplitude My
starts to decrease when the time t1 is exceeded, the maximum value My stored at the time t1 is
stored for a while, but the amplitude My starts to increase again, and the maximum value My so
far at the time t2 And will increase thereafter. Furthermore, since the amplitude My turns to
decrease at time t3, the amplitude My at that time t3 is stored as the maximum value Mymax.
[0086]
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28
Then, since the decreasing width of the amplitude My, which has started to decrease from time
t3, reaches the threshold value Mth1 at time t4, the flag Fdec is set to 1. Therefore, after that, the
determination in step 110 becomes “YES”, and the process proceeds to step 127. Since the
amplitude My continues to decrease for a while after the time t4, the determination in the step
127 becomes "YES" and the minimum value Mymin continues to be updated, and the minimum
value at the time when the amplitude My turns to increase at the time t5 Mymin is saved. Then,
after time t5, the determination in step 127 becomes "NO", so that it proceeds to step 130 to
determine whether the amount of increase from the minimum value Mymin has reached the
threshold value Mth2. Thus, in this example, the determination in step 130 becomes "YES" at
time t6, and the process proceeds to step 126. Thereafter, the process of FIG. 4 is started again,
the amplitude My at time t7 is stored as the new maximum value Mymax, and it is determined
again whether or not a reduction exceeding the threshold value Mth1 has occurred.
[0087]
As described above, in the present embodiment, since the periodic fluctuation state of the drive
signal y can be detected, the processing of step 126 is performed to effectively eliminate or
reduce the periodic fluctuation state. Because the processing required for the detection is
relatively simple, the calculation load on the controller 25 does not increase significantly.
[0088]
Moreover, in the present embodiment, since the cyclic fluctuation state is detected based on the
fluctuation width of the amplitude My, the amplitude My temporarily increases, for example, as
between time t3 and time t4 in FIG. Even if a phenomenon that decreases again after turning to
the ground occurs due to vibration input from the road surface side, etc., it will not stop the
judgment, and cyclic fluctuation state of the drive signal y There is also an advantage that the
possibility of miss is lower than in the first embodiment.
[0089]
Further, in the present embodiment, when at least one of the shift position and the engine speed
changes while executing the processing for detecting the periodic fluctuation state, the
processing is stopped and executed again from the beginning. As a result, the possibility of
erroneous detection of the periodic fluctuation state of the drive signal y can be reduced.
That is, when the engine speed N largely fluctuates due to the accelerator operation or the like,
10-04-2019
29
the generation state of the vibration in the engine 17 also changes accordingly, and therefore the
amplitude My of the drive signal y may also repeatedly increase and decrease. The same
phenomenon may occur when switching, so if the detection process is continued when such a
change is confirmed, the possibility of erroneous detection of a periodic fluctuation state
increases. is there.
[0090]
Furthermore, in the present embodiment, by providing the timers T3 and T4, the processing is
stopped even when a periodic fluctuation state is not detected for a relatively long time after the
maximum value or the minimum value is set, and from the beginning Since it is made to execute
again, this can also reduce the possibility of false detection of the periodic fluctuation state of the
drive signal y.
That is, even if the shift position and the engine speed do not change, for example, when
traveling in the order of flat road → uphill → flat road → uphill, a change in engine vibration
caused by a change in engine load The decrease amount or increase amount of the amplitude My
of the drive signal y may exceed the threshold value, which may be erroneously detected as a
periodic fluctuation state of the drive signal y. Therefore, as in the present embodiment, the
possibility of false detection can be further reduced by putting a time constraint on the
determination of the periodic fluctuation state.
[0091]
Next, the process of changing the divergence suppression coefficient βk executed in step 126 of
FIG. 4 will be described in detail. That is, when the process of step 126 of FIG. 4 is executed, the
process of FIG. 5 is started. First, at step 201, the engine speed signal N is read, and then it
proceeds to step 202 and the engine speed signal A rotation speed band including the engine
rotation speed which is known from N is determined, and information is written in a portion of
the table corresponding to the rotation speed band.
[0092]
Then, the process proceeds to step 203, where the divergence suppression coefficient .beta.k
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30
corresponding to the rotational speed band in which the information is written in step 202 is
increased by one step. Next, the process proceeds to step 204, and it is determined based on the
information written in the table whether or not the engine rotational speed passes through a
plurality of rotational speed bands while the process of FIG. 4 is being performed. Then, if the
determination in step 204 is "YES", the process proceeds to step 205, and the divergence
suppression coefficient β k corresponding to each of the plurality of rotational speed bands
determined to have passed that engine rotational speed , And then the processing of FIG. 5 this
time is finished. If the determination in step 204 is "NO", the process ends without executing the
process of step 205.
[0093]
When the process of FIG. 5 is performed, the processes of steps 201 to 203 are always
performed, so that divergence for the rotational speed band including the engine rotational speed
when it is determined that the periodic fluctuation state is generated. Since the suppression
coefficient βk increases, in the subsequent updating process of the filter coefficient Wi, the
increased divergence suppression coefficient βk is used if the engine speed is included in the
rotation number band, and the filter coefficient Wi is used. Becomes easy to return to the origin
in the updating process, and the periodic fluctuation state is eliminated or suppressed.
[0094]
Then, in the process of FIG. 5, when the determination at step 204 becomes “YES”, not only
the divergence suppression coefficient βk for the engine speed band including the engine speed
at that time, but also adjacent to the engine speed band The divergence suppression coefficients
(βk-1 and βk + 1, etc.) for the other rotation speed bands are also changed, and the divergence
suppression coefficients for the plurality of rotation speed bands all have the same value, and
further, the periodic fluctuation state Can reduce the possibility of
[0095]
The reason will be specifically described. As shown in FIG. 7, when the engine speed is 700 rpm,
one speed band N1 (675 to 700 rpm) and another speed band N2 (700 to 725 rpm) Suppose
that it hits the boundary.
Further, it is assumed that the value of the divergence suppression coefficient βk for one
rotation speed band N1 is 0 and the value of the divergence suppression coefficient βk + 1 for
the other rotation speed band N2 is 5.
10-04-2019
31
The divergence suppression coefficient β is assumed to change stepwise in the range of 0 to 10.
[0096]
Under such circumstances, the engine speed is relatively short in the period between two speed
bands N1 and N2 with 700 rpm in between (at each timing of time t11, t12, t13, t14 and t15 in
FIG. 7). 2.) When the engine speed is in one speed band N1, there is no increase suppression
effect of the filter coefficient Wi by the divergence suppression coefficient βk, conversely, when
the engine speed is in another speed band N2, the divergence is suppressed Since the increase
suppression effect of the filter coefficient Wi by the coefficient βk + 1 is relatively strong, as
shown by the broken line Z in FIG. 7, the average value of the amplitude of the filter coefficient
Wi is in the number of revolutions N1 of one engine speed. It sometimes increases and decreases
when the engine speed is in the other speed band N2.
[0097]
Then, if the increase or decrease of the average amplitude value of the filter coefficient Wi occurs
in a relatively short cycle, it is determined that the periodic fluctuation state is generated in the
processing of FIG. 4, and the processing of FIG. The factor βk or βk + 1 is increased.
If the processing of steps 204 and 205 in FIG. 5 is not included, the periodic fluctuation state as
described above due to the divergence suppression coefficient β k being different for each
rotation speed band is the both divergence suppression coefficient β k and Since the process
continues until .beta..sub.k + 1 matches, eventually both of the divergence suppression
coefficients .beta..sub.k and .beta..sub.k + 1 reach the maximum value 10. FIG. The fact that the
divergence suppression coefficient .beta.k is large means that the filter coefficient Wi is less
likely to be increased, so that the vibration reduction effect by the vibration reduction control is
conversely reduced.
[0098]
However, as in the present embodiment, if the processing of steps 204 and 205 of FIG. 5 is
performed, the engine rotational speed travels through a plurality of rotational speed bands
during execution of the periodic fluctuation state detection processing. If such a determination is
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made, the respective divergence suppression coefficients βk for the plurality of rotational speed
bands are aligned to the largest value among them, In the example, the values of both of the
divergence suppression coefficients βk and βk + 1 may be five. Therefore, the reduction
amount of the vibration reduction effect by the vibration reduction control can be minimized.
[0099]
Here, in the above embodiment, the engine 17 corresponds to a vibration source, the portion of
the active engine mount 20 excluding the load sensor 64 corresponds to a control vibration
source, and the pulse signal generator 19 is a reference signal generating means The load sensor
64 corresponds to the residual vibration detecting means, and the process of generating and
outputting the drive signal y in the controller 25 corresponds to the active control means, and
the filter coefficient Wi according to the equation (3) in the controller 25. The processing for
updating the filter corresponds to the filter coefficient updating means, and the processing for
outputting the filter coefficient Wi in order as the drive signal y in the controller 25 corresponds
to the drive signal generating means, and the above table for storing information for each
rotation speed band The processes of steps 103 and 108 of FIG. 4 and steps 202, 204 and 205
of FIG. 5 correspond to the suppression coefficient adjustment means.
[0100]
In the above embodiment, the processing of FIG. 4 is configured to detect the periodic fluctuation
state of the drive signal y. However, the present invention is not limited to this, and the periodic
fluctuation state of the residual vibration signal e. May be detected.
In the above embodiment, the divergence suppression coefficient βk is changed on the
assumption that the predetermined condition is satisfied when the periodic fluctuation state of
the drive signal y is detected, but the divergence suppression coefficient βk The predetermined
condition to be changed is not limited to this, and may be, for example, when a control
divergence or a divergence tendency is detected. The divergence or divergence tendency of the
control can be detected, for example, by whether the magnitude of the filter coefficient Wi
exceeds a predetermined threshold.
[0101]
Then, in the above embodiment, the values of the divergence suppression coefficients βk are
made to match in step 205 of FIG. 4, but the present invention is not limited to this. For example,
there may be a difference in the value of each divergence suppression coefficient βk, and for
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33
example, each of the plurality of divergence suppression coefficients βk is centered on the
largest divergence suppression coefficient and gradually decreases away from that The value of
the divergence suppression coefficient may be adjusted.
[0102]
Further, in the above embodiment, although the divergence suppression coefficient β k is used
as the suppression coefficient, the condition of the suppression coefficient is whether or not
there is an action to suppress the increase of the filter coefficient Wi. The increasing effect of the
coefficient Wi is strong but the decreasing effect weakens the increasing effect of the filter
coefficient Wi (the effect of suppressing the increase becomes stronger), so the convergence
coefficient α is provided for each rotational speed band, and the convergence coefficients are α
k may be used as the suppression factor in the present invention.
[0103]
And although the above-mentioned embodiment explained the present invention as an active
type vibration control device for vehicles which reduces the vibration transmitted to engine 12
from engine 17, it is not limited to this, for example, as a noise source The present invention may
be an active noise control device that reduces the noise transmitted from the engine 17 of FIG.
In the case of such an active noise control device, a loudspeaker as a control sound source for
generating control sound in the vehicle compartment and a microphone as residual noise
detection means for detecting residual noise in the vehicle compartment are provided. The
loudspeaker may be driven according to the drive signal y obtained by the same arithmetic
processing as in each embodiment, and the output of the microphone may be used as the
residual noise signal e for the updating process of each filter coefficient Wi of the adaptive digital
filter W. .
[0104]
Furthermore, the application object of the present invention is not limited to a vehicle, and an
active vibration control device and an active noise control device for reducing periodic vibration
and noise generated by other than the engine 17 may be used. The invention is applicable, and
the same operation and effect as the above embodiment can be achieved regardless of the
application object.
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For example, the present invention is applicable even to an apparatus or the like for reducing
vibration or noise transmitted from a machine tool to a floor or a room.
[0105]
In each of the above-described embodiments, the case has been described where the
synchronous Filtered-X LMS algorithm is applied as the adaptive algorithm, but the applicable
adaptive algorithm is not limited to this. For example, a normal Filtered-X can be used. It may be
an LMS algorithm or the like.
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