JPH06342309A - Active vibration controller and active noise controller for vehicle - Google Patents

Abstract

PURPOSE:To prevent an increase in arithmetic load at the time of low-frequency vibration and high-frequency noise input and deterioration in control precision at the time of high-frequency vibration and high-frequency noise input without causing trouble such as a great increase in cost. CONSTITUTION:A controller 20 generates a driving signal (y) by using adaptive algorithm on the basis of a reference signal (x) consisting of an impulse train having the same period with periodic vibration generated by an engine 30 and a residual vibration signal (e) showing the vibration state of a member, and supplies it to the electromagnetic actuator 13 of an engine mount 1 interposed between the engine 30 and member. Then a sampling clock as the generation period of the driving signal (y) is switched according to the frequency of the vibration so that the high-frequency side becomes shorter than the low-frequency side; and a transfer function filter which is required for the adaptive algorithm is varied according to the switching of the sampling clock.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active vibration control device for a vehicle, an engine, etc., for reducing the vibration by interfering the control vibration with the periodic vibration emitted from a vibration source such as an engine and propagating in a vehicle body. The present invention relates to an active noise control device for a vehicle, which reduces noise by interfering control noise with noise transmitted from the noise source to the vehicle interior, and in particular to the vibration or noise as a reference signal indicating a vibration or noise generation state. In a device using synchronized impulse trains, it is possible to obtain a stable vibration noise reduction effect against vibration or noise in a wide frequency band.

[0002]

2. Description of the Related Art As a conventional technique of this type, there are those described in British Patent No. 2149614 and Japanese Patent Publication No. 1-501344. These conventional devices are noise reduction devices applied to aircraft cabins and similar closed spaces, and a single noise source such as an engine located outside the closed space has a fundamental frequency f ₀ and its harmonics. It operates under the condition that noise including the waves f _{1 to} f _n is generated.

[0003] More specifically, includes a microphone for detecting a plurality of the installed sound pressure to a location within the closed space, and a plurality of loudspeakers for generating a control sound to the closed space, the frequency f ₀ of the noise source - Based on the f _n component, those frequencies f ₀ ~
The loudspeaker is driven by a signal having a phase opposite to that of the f _n component,
Therefore, a control sound having a phase opposite to that of the noise transmitted to the closed space is generated from the loudspeaker to cancel the noise.

Then, as a method of generating the control sound emitted from the loudspeaker, PROCEEDINGS OF THE IEEE, VOL.
63 PAGE 1692,1975, “ADAPTIVE NOISE CANSELLATION:
PRINCIPLES AND APPLICATIONS ”
An algorithm that applies the DROW LMS 'algorithm to multiple channels is applied. The content of the paper is "A MULTIPLE ERROR LMS ALGORITHM AND
ITS APPLICATION TOTHE ACTIVE CONTROL OF SOUND AND
VIBRATION ”, IEEE TRANS.ACOUST., SPEECH, SIGNAL PRO
CESSING, VOL.ASSP −35, PP. 1423−1434, 1987.

That is, the LMS algorithm is one of the algorithms suitable for updating the filter coefficient of the adaptive digital filter, and is, for example, a so-called Filter.
In the ed-X LMS algorithm, a transfer function filter that models the transfer function from the loudspeaker to the microphone is set for all combinations of the loudspeaker and the microphone, and a reference signal representing the noise generation state of the noise source is set. Update the filter coefficient of the adaptive digital filter with variable filter coefficient provided for each loudspeaker so that the value of the predetermined evaluation function based on the value processed by the filter and the residual noise detected by each microphone is reduced. is doing.

Further, as another conventional active noise control device, there is a device described in "Acoustic Society of Japan 1992 Spring Research Presentation Lecture Proceedings", pages 515-516. Synchronous Filtered-X
It is called an LMS algorithm, and is characterized in that an impulse train synchronized with the fundamental frequency of noise is applied as a reference signal representing the noise generation state. That is, in such a conventional device, since the reference signal is an impulse train, multiplication is unnecessary, convolution calculation can be performed only by addition, and addition is not necessary in some cases. Therefore, there is an advantage that the processing can be performed at high speed.

[0007]

Certainly, the above-mentioned synchronous F
When the iltered-X LMS algorithm is applied, there is an advantage that the calculation load is reduced as a result of simplifying the convolution calculation. However, when the period of vibration or noise to be reduced is long (when the frequency is low) and when the period is short (when the frequency is high), the former is the number of filter coefficients of the adaptive digital filter that outputs within one period. However, there is an imbalance in that the calculation load is large due to the large number of calculation errors and therefore the calculation load is large. Clock (sampling of residual vibration signal and residual noise signal
It is a clock, which has to be determined to be equal to the drive signal generation period. However, when the sampling clock is determined in this way, in the case of high frequency vibration, high frequency noise input, etc. The sampling clock becomes relatively coarse with respect to the noise cycle, and the number of drive signals output in one cycle becomes small, so that it is not possible to expect highly accurate vibration reduction control or noise reduction control. .

To solve such a problem, the number of drive signals output in one cycle is fixed, that is, vibration reduction control and noise reduction control are always performed using 1 / N of one cycle as a sampling clock. Measures can be considered. However, if such a solution is adopted, sampling
Since the clock changes continuously, it is necessary to change the transfer function filter expressed on the time axis continuously by following the continuous change of the sampling clock. Therefore, vibration reduction control, noise reduction control, etc. It is necessary to perform transfer function identification processing in parallel with the above, or to store in memory a large number of types of transfer function filters.
Therefore, it is necessary to develop an identification method that does not significantly increase the calculation load or install a large-capacity memory.

The present invention has been made by paying attention to such unsolved problems in the prior art, and does not cause problems such as deterioration of control accuracy during high frequency vibration and high frequency noise input, and the like. Synchronous Filtered-X
An object of the present invention is to provide an active vibration control device for a vehicle and an active noise control device for a vehicle that can effectively utilize the advantages of the LMS algorithm.

[0010]

In order to achieve the above object, an active vibration control device for a vehicle according to the invention of claim 1 interferes with periodic vibrations emitted from a vibration source and propagating in a vehicle body. Control vibration source capable of generating control vibration, reference signal generating means for generating a reference signal having an impulse train of the same cycle as the periodic vibration, and vibration after the interference is detected and output as a residual vibration signal. Residual vibration detection means,
Reference processing signal generating means for generating a reference processing signal by convolving the transfer function filter modeling the transfer function between the control vibration source and the residual vibration detecting means, and the reference signal and the filter coefficient of the transfer function filter. An adaptive digital filter having a variable filter coefficient, and the filter coefficients of the adaptive digital filter are sequentially output to the control vibration source as drive signals at intervals of a predetermined sampling clock from the time when the latest impulse of the reference signal is generated. Drive signal generating means, adaptive processing means for updating the filter coefficient of the adaptive digital filter based on the reference signal and the residual vibration signal so as to reduce the vibration after the interference, and the frequency of the vibration is detected. High frequency based on the frequency detection means and the frequency of the vibration detected by this frequency detection means A sampling clock switching means for switching the predetermined sampling clock so that is shorter than the low frequency side, and a transfer function filter changing means for changing the transfer function filter according to the switching of the sampling clock switching means. Prepared

In order to achieve the above object, the vehicle active noise control device according to a second aspect of the invention is a control for interfering with periodic noise emitted from a noise source and transmitted to the vehicle interior. A control sound source capable of generating sound, reference signal generating means for generating a reference signal having an impulse train having the same period as the periodic noise, and residual noise detection for detecting the noise after the interference and outputting it as a residual noise signal. Means, a transfer function filter modeling a transfer function between the control sound source and the residual noise detecting means, and a reference processing signal for generating a reference processing signal by convolving the reference signal and the filter coefficient of the transfer function filter. Generating means, an adaptive digital filter with variable filter coefficient, and the adaptive function at a predetermined sampling clock interval from the time when the latest impulse of the reference signal is generated. Drive signal generating means for sequentially outputting the filter coefficients of the digital filter as a drive signal to the control sound source, and a filter of the adaptive digital filter so as to reduce the noise after the interference based on the reference signal and the residual noise signal. Adaptive processing means for updating the coefficient, frequency detection means for detecting the frequency of the noise, and the predetermined sampling clock so that the high frequency side becomes shorter than the low frequency side based on the frequency of the noise detected by the frequency detection means. And a transfer function filter changing means for changing the transfer function filter according to the switching of the sampling clock switching means.

[0012]

According to the first aspect of the present invention, the drive signal generating means sets the filter coefficient of the adaptive digital filter at a predetermined sampling clock interval from the time when the latest impulse generated by the reference signal generating means is generated. Since the control vibration is output to the controlled vibration source in order as a drive signal, the controlled vibration corresponding to the filter coefficient of the adaptive digital filter is generated from the controlled vibration source. The vibration propagating in the vehicle body is not necessarily reduced because the vibration does not necessarily converge to the.

However, the adaptive processing means is based on the reference processing signal generated by the reference processing signal generating means by convolving the reference signal and the filter coefficient of the transfer function filter, and the residual vibration signal detected by the residual vibration detecting means. However, since the filter coefficient of the adaptive digital filter is updated so that the vibration after interference is reduced, the filter coefficient of the adaptive digital filter converges to the optimum value as the control progresses, and therefore, the control generated from the control vibration source is controlled. The vibration cancels the vibration and reduces the vibration level.

On the other hand, when the frequency detecting means detects the frequency of the vibration emitted from the vibration source, the sampling / clock switching means performs sampling / clocking based on the detection result.
Since the clock is switched, the generation period of the drive signal when the high frequency vibration occurs is shorter than the generation period of the drive signal when the low frequency vibration occurs. Therefore, the generation cycle of the drive signal does not become rough when high frequency vibration occurs.

Further, the transfer function filter changing means changes the transfer function filter according to the switching of the sampling clock by the sampling clock switching means.
Therefore, if the sampling clock and the transfer function filter are appropriately associated and set in advance, the sampling
Even if the clock length is changed, the transfer function filter expressed by the time interval of the sampling clock is used. Therefore, the transfer function identification process is unnecessary, and it is sufficient to set the transfer function filter corresponding to the stepwise sampling clock, so that a large capacity memory is not necessary.

The invention described in claim 1 is intended for vibration, whereas the invention claimed in claim 2 is intended for noise. Therefore, the operation of the invention of claim 2 is substantially the same as that of claim 1 although there is a difference between vibration and sound.
It is similar to the described invention.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the present invention. In this embodiment, a so-called active vibration control apparatus for a vehicle according to the present invention is used to actively reduce vibration transmitted from an engine to a vehicle body. It is applied to the engine mount.

First, the structure will be described. As shown in FIG. 1, the engine mount 1 is integrally provided with a mounting bolt 2a for mounting the engine 30 as a vibration source on the upper side, and has a hollow inside and a lower side. The mounting member 2 has an opening, and the upper end of the inner cylinder 3 is caulked to the outer surface of the lower portion of the mounting member 2. Inside the inner cylinder 3, a diaphragm 4 is disposed so as to vertically divide the space inside the mounting member 2 and the inner cylinder 3 into two parts, which are sandwiched by the caulking prevention portions of the mounting member 2 and the inner cylinder 3. Of the space divided by the diaphragm 4, the space above the diaphragm 4 communicates with the atmospheric pressure, and the space below the diaphragm 4 is provided with the orifice structure 5.

On the other hand, on the outer peripheral surface of the inner cylinder 3, the inner peripheral surface of a cylindrical support elastic body 6 which is formed such that the axial positions of the inner peripheral surface and the outer peripheral surface are higher on the inner peripheral side is vulcanized. The outer peripheral surface of the supporting elastic body 6 is vulcanized and adhered to the inner peripheral surface of the outer cylinder 7. The lower end of the outer cylinder 7 is caulked to the upper portion of the cylindrical actuator holding member 8, and the lower end surface of the actuator holding member 8 is provided with a mounting bolt 9a for mounting the member 35 as a vehicle body on the lower side. A disc-shaped mounting member 9 provided integrally is fixed.

A cylindrical member 10 fixed to the lower end portion of the outer cylinder 7 by caulking is fixed to the upper end surface of the actuator holding member 8 and further to the inner peripheral surface of the cylindrical member 10. The movable member 12 is held by the cylindrical elastic body 11 so as to be vertically displaceable with a predetermined clearance from the upper end surface of the actuator holding member 8. The movable member 12 is made of a magnetizable material and is formed into a disk shape having a concave upper surface.

Inside the actuator holding member 8, there is arranged an electromagnetic actuator 13 including an electromagnetic coil and the like, which displaces the movable member 12 in the vertical direction according to a control signal supplied from the outside. There is. Further, in this embodiment, the lower surface of the support elastic body 6 and the movable member 1 are
2, a main fluid chamber 15 is formed in a portion defined by the upper surface of the second fluid, and a sub fluid chamber 16 is formed in a portion defined by the diaphragm 4 and the orifice structure 5. The chambers 16 communicate with each other via the orifice 5a formed in the orifice structure 5. A fluid such as oil is enclosed in the main fluid chamber 15, the sub fluid chamber 16 and the orifice 5a.

The characteristics of the fluid mount, which is determined by the flow path shape of the orifice 5a and the like, are the characteristics of the engine mount 1 when an engine shake occurs during running, that is, at 5 to 15 Hz.
Is adjusted so that it exhibits a high dynamic spring constant and high damping force when is excited. The electromagnetic actuator 13 is connected to the controller 20 and generates a predetermined electromagnetic force according to the drive signal y supplied from the controller 20.

The controller 20 includes a microcomputer, necessary interface circuits, A / D converter, D / A
It is composed of a converter, an amplifier, etc., and is a vibration in a frequency band in which a fluid cannot move between the main fluid chamber 15 and the sub-fluid chamber 16 through the orifice 5a, that is, a vibration of a higher frequency than the engine shake described above. When idle vibration, muffled sound vibration, or vibration during acceleration is input, the transmission force to the mounting member 9 becomes “0” in synchronization with the vibration (specifically, the support elastic body 6 The drive signal y is generated and supplied to the electromagnetic actuator 13 so that the input due to the elastic deformation and the input due to the volume change of the main fluid chamber 15 can be canceled out.

Here, idle vibration and muffled sound vibration are
For example, in the case of a reciprocating 4-cylinder engine, the engine rotation 2
The main cause is that the engine vibration of the next component is transmitted to the member 35 via the engine mount 1. Therefore, if the drive signal y is generated and output in synchronization with the engine rotation secondary component, the vibration transmissibility Can be reduced. Therefore, in the present embodiment, an impulse signal that is synchronized with the rotation of the crank angle of the engine 30 (for example, in the case of a reciprocating 4-cylinder engine, one impulse is generated every 180 degrees of the crank) is generated and output as the reference signal x. A pulse signal generator 21 as a reference signal generating means is provided, and the reference signal x is supplied to the controller 20 as a signal indicating a vibration generation state in the engine 30.

On the other hand, the member 35 is the engine mount 1
The acceleration sensor 22 as a residual vibration detecting means for detecting the vibration state of the member 35 in the form of acceleration and outputting it as a residual vibration signal e is fixed in the vicinity of the mounting position of, and the residual vibration signal e interferes. The signal is supplied to the controller 20 as a signal indicating the later vibration. Then, the controller 20 is based on the reference signal x and the residual vibration signal e, and is a Filtered-X LMS algorithm which is one of the adaptive algorithms of the successive update type.
More specifically, the synchronous Filtered-X LMS
The drive signal y is generated and output according to the algorithm.

That is, the controller 20 has an adaptive digital filter W having a variable filter coefficient W _i (i = 0, 1, 2, ..., I-1: I is the number of taps), and the latest reference signal x Is output from the engine 30 via the engine mount 1 at a predetermined sampling clock interval and the filter coefficient W _i of the adaptive digital filter W is sequentially output as the drive signal y.
A process of appropriately updating the filter coefficient W _i of the adaptive digital filter W is executed based on the reference signal x and the residual vibration signal e so that the vibration transmitted to the device is reduced.

The update formula of the adaptive digital filter W is F
The following equation (1) follows the iltered-X LMS algorithm. _{W i (n + 1) =} W i (n) -αR T e (n) ...... (1) where, indicates that a value at term time n stick is (n), also, alpha is a convergence factor It is a coefficient that is called and is related to the speed of convergence of the filter coefficient W _i and its stability. R ^T is theoretically a value (reference signal or Filtered-X signal) obtained by filtering the reference signal x with a transfer function filter C ^ representing the transfer function C between the engine mount 1 and the acceleration sensor 22. In this embodiment, since the reference signal x is an impulse train as a result of applying the synchronized Filtered-X LMS algorithm, those impulses when the impulse response of the transfer function filter C ^ is generated in synchronization with the reference signal x one after another. It matches the sum of the response waveforms at time n.

Further, theoretically, the reference signal x is filtered by the adaptive digital filter W to generate the driving signal y, and the filtering process corresponds to the convolution operation in the digital operation, but the reference signal x is Since it is an impulse train, even if each filter coefficient W _i of the adaptive digital filter W is sequentially output as the drive signal y at a predetermined sampling clock interval from the time when the latest reference signal x is input as described above. , The same result as when the filtering result is the drive signal y.

Further, the controller 20 controls the engine 3
It has a function of detecting the frequency of vibration transmitted from 0 to the member 35 via the engine mount 1. Specifically, based on the number of drive signals y output in one cycle of the reference signal x and the sampling clock at that time,
It has a calculation function for obtaining the frequency of the vibration transmitted to the member 35, and based on the calculated frequency of the vibration,
It is judged whether the vibration is in the low frequency band or the high frequency band with a predetermined threshold as a boundary, and depending on the result of the judgment, it becomes shorter when it is judged that it is in the high frequency band. In addition, the sampling clock, which is the generation period of the drive signal y and the reading interval of the residual vibration signal e, is switched in two steps.

Furthermore, the controller 20 has a transfer function filter C ^ individually corresponding to each of the sampling clocks switched in two stages and sampled at intervals of each sampling clock. The transfer function filter C ^ used when calculating the reference signal R ^T is changed in accordance with the switching of.

Next, the operation of this embodiment will be described. That is,
When an engine shake occurs, the shape of the flow path of the orifice 5a is appropriately selected.
Since it functions as a support device for high dynamic spring constant and high damping force, the engine shake generated in the engine 30 is damped by the engine mount 1 and the vibration level on the member 35 side is reduced. In such a case, it is not particularly necessary to displace the movable member 12.

On the other hand, when vibration at a frequency higher than the idle vibration frequency at which the fluid in the orifice 5a becomes a stick state and the fluid cannot move between the main fluid chamber 15 and the sub-fluid 16 is input, the controller 20 executes a predetermined arithmetic processing, outputs a drive signal y to the electromagnetic actuator 13, and causes the engine mount 1 to generate an active control force capable of reducing vibration.

This will be specifically described with reference to FIG. 2, which is a flow chart showing an outline of the processing executed in the controller 20 when the idle vibration and the muffled sound vibration are input.
First, after performing a predetermined initialization in step 101, the process proceeds to step 102a, and it is determined whether or not the output count T _y of the drive signal y in the previous process is larger than the threshold value A.

That is, in the first processing, the output count T _y is set to a predetermined initial value, but in the second and subsequent processing, the number of times the drive signal y is actually output is the output count T y. _It is stored as _y , and the output frequency T _y corresponds to the frequency of the actual vibration. That is, this step 102a
If the determination is YES, it means that the drive signal y is output A times or more within one cycle, and therefore the threshold value A
It can be determined that the low-frequency side vibration is occurring at the boundary.

Here, since it is considered that the low frequency side vibration is occurring, the determination at step 102a is "YES" and the routine proceeds to step 103a. Then, step 103a
Then, as the transfer function filter C ^, the transfer function filter C ^ _L for low-frequency side vibration input is read. Such transfer function filter C ^ _L is a digital filter consisting of a preset sequence by sampling increment response at intervals of the sampling clock SC _L for the low-frequency side processing execution described below.

Next, in step 104a, the reference signal R ^T is calculated based on the transfer function filter C ^ _L. In this step 104a, the reference signals R ^T for one cycle are collectively calculated. Then, the process shifts to step 105a to clear the counter i to zero, and then shifts to step 106a to output the i-th filter coefficient W _i of the adaptive digital filter W as the drive signal y.

When the drive signal y is output in step 106a, the process proceeds to step 107a to reset / start a timer for measuring the sampling interval. When the residual vibration signal e is read in step 108a, the counter j is cleared to zero in step 109a, and then step 110a is performed to set the j-th filter coefficient W _j of the adaptive digital filter W to the above ( Update according to equation 1).

When the updating process in step 110a is completed, the process proceeds to step 111a, and it is determined whether or not the next reference signal x is input. If it is determined that the reference signal x is not input, , The process proceeds to step 112a in order to update the next filter coefficient of the adaptive digital filter W or output the drive signal y. In step 112a, it is determined whether or not the counter j has reached the output count T _y (more precisely, since the counter j starts from 0, the output count T _y minus 1). In this determination, after outputting the filter coefficient W _i of the adaptive digital filter W as the drive signal y in step 106a, the filter coefficient of the adaptive digital filter W is
This is for determining whether or not the necessary number of drive signals y have been updated. Therefore, if the determination in step 112a is "NO", after the counter j is incremented in step 113a, the process returns to step 110a and the above-described processing is repeatedly executed.

However, the determination in step 112a is "YE
In the case of “S”, it can be determined that the updating process of the necessary number of filter coefficients as the drive signal y among the filter coefficients of the adaptive digital filter W has been completed.
Move to 4a. Then, after incrementing the counter i in step 114a, the procedure proceeds to step 115a, measurement value of the timer started in the step 107a is, wait until a sampling clock SC _L for the low frequency side processing executing. This step 115a
In If the measured value of the timer reaches the sampling clock SC _L, it repeats the process described above returns to the step 106a.

However, if it is determined in step 111a that the reference signal x has been input, the process proceeds to step 116a, and the counter i (to be precise, since the counter i starts from 0, 1 is added to the counter i). Value) is stored as the latest output count T _y , and then the process returns to step 102a to repeatedly execute the above-described processing. On the other hand, if the determination in step 102a is "NO", the drive signal y is output less than A times in one cycle, so that the threshold value A is used as a boundary and the high frequency side is set. It can be determined that the vibration is occurring.

Therefore, in order to execute the calculation process when the high-frequency side vibration occurs, the process proceeds to step 103b, but the processing contents of steps 103b to 116b are the same as step 103b.
And the processing contents of 115b are slightly different, and are essentially the same as the processing contents of steps 103a to 116a described above. That is, in step 103b, unlike the processing in step 103a,
As the transfer function filter C ^, the transfer function filter C ^ _H for high-frequency side vibration input is read, and in step 115b, the measured value of the timer started in step 107b is the sampling clock SC for high-frequency side process execution. Wait until _H is reached. Here, the relationship between the sampling clock SC _H for executing the high frequency processing and the sampling clock SC _L for executing the low frequency processing is SC _H <SC _L , which is shorter on the high frequency side. Further, transfer function filter C ^ _H for at the high frequency side vibration input is a digital filter consisting of a preset sequence by sampling increment response at intervals of the sampling clock SC _H for high-frequency side processing execution.

Further, after performing the processing of step 116b, the process proceeds to step 102b, and the latest output count T _y
Is smaller than a predetermined threshold value B, and if the determination in step 102b is “NO”, that is, it is determined that vibration on the low frequency side occurs at the threshold value B as a boundary. If possible, the process proceeds to step 103a, and if the determination in step 102b is “YES”, that is, if it can be determined that vibration on the high frequency side with the threshold value B as a boundary is occurring, the process proceeds to step 103b. To do. The relationship between the threshold values A and B is that A> B has a hysteresis in order to stabilize the control system.

As a result of repeatedly executing such processing,
Reference signal x, as shown in FIG. 3 which represents the drive signal y and the transfer function filter C ^ relationship, from the controller 20 to the engine mount 1, from the time when the reference signal x is input, the sampling clock SC _L or at intervals of SC _H, but the filter coefficient W _i of the adaptive digital filter W is supplied as a drive signal y in order, each filter coefficient W _i of the adaptive digital filter W is synchronous Filte
Since it is sequentially updated by the above (1) according to the red-X LMS algorithm, after a certain amount of time has passed and each filter coefficient W _i of the adaptive digital filter W has converged to an optimum value, the drive signal y is changed to the engine. By being supplied to the mount 1, idle vibration and muffled sound vibration transmitted from the engine 30 to the member 35 side via the engine mount 1 are reduced. The control force in the engine mount 1 causes the movable member 12 to vibrate due to the electromagnetic force generated from the electromagnetic actuator 13, and the vibration causes the fluid in the main fluid chamber 15 and the support elastic body 6 to vibrate.
It is obtained by acting as a force between the inner cylinder 3 and the outer cylinder 7 via the expansion spring of.

Further, in the present embodiment, the process executed at the time of low-frequency side vibration input and the process executed at the high-frequency side vibration input are individually set, and the sampling clock SC having the above-described relationship is set for each. _L and sampling
Because you set the clock SC _H, output interval of the drive signal y, at the time of the low frequency side vibration input becomes as relatively long 4, when the high frequency side of vibration input, relatively short, as shown in FIG.

Therefore, when the low frequency side vibration is input, the number of drive signals y output in one cycle becomes too large, and the number of filter coefficients W _i of the adaptive digital filter W to be updated becomes large, resulting in an extremely heavy calculation load. Therefore, it is possible to prevent the control accuracy from decreasing due to a large number and the number of drive signal signals y output in one cycle when high frequency vibration is input.

In this embodiment, the transfer function filter C
Two types of ^ are prepared, one for the low frequency side and one for the high frequency side, and the respective transfer function filters C ^ are respectively set to sampling clocks SC _{L as} shown in FIG. 4 or FIG.
Or because of the set at intervals of SC _H, nor accuracy of updating the filter coefficients W _i of the adaptive digital filter W is deteriorated.

The transfer function filter C ^ only needs to set in advance a type corresponding to the number of sampling clocks (two in this embodiment) that can be switched. It does not require a troublesome calculation process and does not require a large-capacity memory. Therefore,
The cost does not increase significantly. Further, as can be seen by comparing FIG. 4 and FIG. 5, when the frequency of vibration becomes high, the filter coefficients of many transfer function filters C ^ for calculating the reference signal R ^T are higher than when the frequency of vibration is low. Will have to be added together. However, it is known that if the number of additions exceeds a certain number, the accuracy will not be significantly affected by addition or non-addition, because of the relationship with the accuracy of the transfer function filter C ^. Therefore, if an upper limit value is appropriately set for the number of additions, the calculation load can be reduced.

Here, in this embodiment, the engine mount 1 constitutes a controlled vibration source, and step 10
Reference processing signal generation means is constituted by the processing of 3a and 103b, and drive signal generation means is constituted by the processing of steps 108a, 109a, 115a and 108b, 109b, 115b, and steps 110a and 110b.
The adaptive processing means is constituted by the processing of step 11
5a, 116a and 115b, 116b constitute a frequency detecting means, and steps 102a, 115
The processing of a, 102b and 115b constitutes the sampling / clock switching means, and the processing of steps 103a and 103b constitutes the transfer function filter changing means.

Although the sampling clocks are switched in two stages in the above embodiment, the present invention is not limited to this, and may be three stages or more. Also,
In the above-described embodiment, the vibration frequency is detected based on the output frequency T _y of the drive signal y. However, the means for detecting the vibration frequency is not limited to this, and for example, the rotation of the engine 30 may be changed. You may read from the number.

Further, even if the transfer function filters C ^ for the low frequency and the high frequency are not individually set, for example, the transfer function filters C ^ are set at fine time intervals, and the filter coefficients are appropriately thinned out. It may be used for low frequency and high frequency. In the above embodiment, the case where the active vibration control device for a vehicle according to the present invention is applied to a so-called active engine mount for reducing the vibration transmitted from the engine 30 to the member 35 has been described. The application target of is not limited to this, and may be a device that reduces the vibration generated from other than the engine 30 as long as it is periodic vibration.

Furthermore, the object of reduction is not limited to vibration, but may be, for example, an active noise control device for a vehicle that actively reduces periodic noise transmitted from the engine 30 into the vehicle interior. . In such a case, a loudspeaker (control sound source) that is driven by a drive signal supplied from the controller to generate a control sound in the vehicle compartment, and a microphone that detects residual noise in the vehicle compartment and outputs the residual noise signal to the controller ( Residual noise detecting means).

[0052]

As described above, according to the present invention,
Depending on the frequency of vibration or noise, the sampling clock is switched so that the high frequency side is shorter than the low frequency side, and the transfer function filter is changed according to the switching of the sampling clock. There is an effect that it is possible to prevent an increase in calculation load at the time of inputting low-frequency vibrations and high-frequency noises and deterioration of control accuracy at the time of inputting high-frequency vibrations and high-frequency noises without causing a problem such as a large increase in noise. .

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart showing an outline of processing executed in a controller.

FIG. 3 is a waveform diagram showing a relationship between a reference signal, a drive signal, and a transfer function filter.

FIG. 4 is a waveform diagram showing a relationship between a drive signal and a transfer function filter when a low frequency vibration is input.

FIG. 5 is a waveform diagram showing a relationship between a drive signal and a transfer function filter when a high frequency vibration is input.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 engine mount (controlled vibration source) 13 electromagnetic actuator 20 controller 21 pulse generator (reference signal generation means) 22 acceleration sensor (residual vibration detection means) 30 engine (vibration source) 35 member (vehicle body) x reference signal y drive signal e Residual vibration signal

Claims (2)

[Claims] 1. A control vibration source capable of generating a control vibration that interferes with a periodic vibration emitted from a vibration source and propagating through a vehicle body, and a reference signal composed of an impulse train having the same period as the periodic vibration. A reference signal generating means, a residual vibration detecting means for detecting the vibration after the interference and outputting it as a residual vibration signal, a transfer function filter modeling a transfer function between the control vibration source and the residual vibration detecting means, Reference processed signal generating means for generating a reference processed signal by convolving the reference signal and the filter coefficient of the transfer function filter;
An adaptive digital filter having a variable filter coefficient, and a drive for outputting the filter coefficient of the adaptive digital filter as a drive signal to the controlled vibration source in order at a predetermined sampling clock interval from the time when the latest impulse of the reference signal is generated. Signal generating means, adaptive processing means for updating the filter coefficient of the adaptive digital filter so as to reduce the vibration after the interference based on the reference signal and the residual vibration signal, and frequency detection for detecting the frequency of the vibration. Means and sampling clock switching means for switching the predetermined sampling clock so that the high frequency side becomes shorter than the low frequency side based on the frequency of the vibration detected by the frequency detecting means, and the sampling clock switching means.
An active vibration control device for a vehicle, comprising: transfer function filter changing means for changing the transfer function filter according to switching of the clock switching means. 2. A control sound source capable of generating a control sound that interferes with a periodic noise emitted from a noise source and transmitted to a vehicle interior, and a reference signal composed of an impulse train having the same period as the periodic noise. Reference signal generating means for generating, residual noise detecting means for detecting the noise after the interference and outputting as a residual noise signal, a transfer function filter modeling a transfer function between the control sound source and the residual noise detecting means, Reference processing signal generating means for generating a reference processing signal by convolving the reference signal and the filter coefficient of the transfer function filter, a filter coefficient variable adaptive digital filter, and a time point when the latest impulse of the reference signal is generated. From the drive signal, the filter coefficient of the adaptive digital filter is sequentially output as a drive signal to the control sound source at a predetermined sampling clock interval from Generating means, adaptive processing means for updating the filter coefficient of the adaptive digital filter so as to reduce the noise after the interference based on the reference signal and the residual noise signal, and frequency detecting means for detecting the frequency of the noise. And a sampling clock switching means for switching the predetermined sampling clock so that the high frequency side becomes shorter than the low frequency side based on the frequency of the noise detected by the frequency detecting means, and in response to the switching of the sampling clock switching means. And a transfer function filter changing means for changing the transfer function filter.