JP2009062023A - Active vibration and noise control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active vibration and noise control device for a vehicle, which minimizes the road noise generated while the vehicle is traveling on an asphalt paved surface, or on a concrete paved surface. <P>SOLUTION: In the active vibration and noise control device, when the vehicle is traveling on an asphalt paved surface, a first signal processor 51 to be operated at 40 Hz and a second signal processor 52 to be operated at 70 Hz are operated in parallel to reduce the road noise of 40 Hz and 70 Hz components. On the other hand, when the vehicle is traveling on a concrete paved surface, an increased component of 50 Hz included in the first control signal generated by the first signal processor operated at 40 Hz is subtracted from the first control signal Sc1 by a subtractor 318 to generate the canceled signal Scp1 by a first phase gain regulator 46, and only the noise component (the road noise component) of 40 Hz is effectively reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides an active vibration noise control for a vehicle that generates a canceling sound having an opposite phase and equal amplitude of road noise, which is noise generated in the vehicle interior due to traveling of the vehicle, and reducing the road noise by interfering with the road noise. Relates to the device.

  The vibration of the wheel received from the road (road) is transmitted to the vehicle body through the suspension, and is excited by the acoustic resonance characteristic of a closed space such as a passenger compartment, and has a peak at about 40 Hz and a 20 to 150 Hz bandwidth load. An active vibration noise control device for a vehicle that cancels out noise (also called “go”, also called drumming noise) by a canceling sound having a phase opposite to that of the road noise at an evaluation point (listening point) where the microphone is disposed. It has been proposed (Patent Document 1).

  Generally, the peak (first peak) which is the maximum value of road noise exists at about 40 Hz as described above, but there is a second peak at about 70 Hz.

  FIG. 9 shows the configuration of an active vibration noise control device 200 for a vehicle corresponding to two frequencies of 40 Hz (ω0 = 2π × 40) and 70 Hz (ω1 = 2π × 70) to which the technique proposed in Patent Document 1 is applied. Is shown.

  The two processing circuits 201A and 201B respectively include a sine wave generation unit 202 and a cosine wave generation unit 203 that generate sine waves having frequencies of 40 Hz and 70 Hz, and outputs of the sine wave generation unit 202 and the cosine wave generation unit 203, respectively. 2 and the coefficient updating means 206 and 207, and the coefficient updating means 206 and 207 sequentially update the coefficients of the 1-tap digital filters 204 and 205 corresponding to the respective one-tap digital filters 204 and 205. Yes.

  The outputs of the two processing circuits 201 </ b> A and 201 </ b> B are added by the adder circuit 211, the amplitude and phase are adjusted by the adjustment circuit 208, and added to the speaker 209. An error signal, which is an output of the microphone 210 that is an interference sound between the canceling sound and the road noise from the speaker 209, is added to the inputs of the processing circuits 201A and 201B.

JP 2007-25527 A

  However, it has been found that the vehicle active vibration noise control apparatus 200 shown in FIG. 9 has the following problems.

  Regarding road noise, it was found that there is a road (road) having a maximum peak at about 40 Hz, but almost no second peak at about 70 Hz. Specifically, there is almost no second peak on the concrete paved road. Note that there is a significant second peak on the asphalt paved road.

  Long-life concrete paved roads are used for paving in highways, for example, in tunnels where pavement replacement work is difficult. That is, during traveling on a concrete paved road, the processing circuit 201B of the vehicular active vibration noise control device 200 shown in FIG. 9 for processing 70 Hz becomes redundant.

  Therefore, it is conceivable to reduce the 40 Hz component only by the processing circuit 201A that processes 40 Hz without operating the processing circuit 201B while traveling on a concrete paved road where the second peak does not exist at about 70 Hz. However, in this case, although the 40 Hz component can be reduced, it has been found that noise (circuit gain) increases conversely in the components of about 30 Hz and about 50 Hz on both sides of the 40 Hz component. In practice, since the speaker 209 does not respond to the 30 Hz component (because there is no gain), the noise does not increase. However, since the 50 Hz component is in the response range of the speaker 209, the noise increases due to an increase in circuit gain. It was found that this 50 Hz noise can be heard as annoying noise while traveling on a concrete paved road where the second peak does not exist at about 70 Hz.

  The present invention has been made in consideration of such problems, and an object thereof is to provide an active vibration noise control device for a vehicle that enables optimal noise reduction control according to road surface conditions. To do.

  In this section, for ease of understanding, reference numerals in the attached drawings are used for explanation. Therefore, the contents described in this section should not be construed as being limited to those having the reference numerals.

  The active vibration noise control device for a vehicle according to the present invention includes, for example, a first reference signal generator (26) that generates a first reference signal related to a first frequency component of road noise, as shown in FIG. A first adaptive filter (33) that generates a first control signal based on a first reference signal; and a first filter coefficient updater (39) that sequentially updates the first filter coefficient of the first adaptive filter. A first signal processor (51); a second reference signal generator (126) for generating a second reference signal relating to a second frequency component of road noise; and a second control signal based on the second reference signal. The second adaptive filter (133), the second filter coefficient updater (139) for sequentially updating the second filter coefficient of the second adaptive filter, the second signal processor (151), and the first Control signal A first phase adjuster (46) for adjusting a phase and generating a cancellation signal; a second phase adjuster (146) for adjusting a phase of the second control signal and generating a cancellation signal; and the cancellation signal A canceling sound output device (8) for outputting as a canceling sound, and an error signal detector (6) for detecting residual vibration noise due to interference between the canceling sound and the road noise at an evaluation point as an error signal, The first filter coefficient updater updates the first filter coefficient based on an addition signal of the error signal and the first control signal one sample before, and the second filter coefficient updater includes the error signal and the error signal. A road surface input detector (306) for detecting an input from the road surface to the vehicle in the vehicular active vibration noise control apparatus that updates the second filter coefficient based on an addition signal with the second control signal one sample before. )When, Based on the serial road surface input, the switch for switching the control of the second signal processor and (SW1, SW3, SW4), characterized by comprising a.

  According to the present invention, the first signal processor having the first adaptive filter that generates the first control signal based on the first reference signal related to the first frequency component of the road noise is always operated and the second noise of the road noise is obtained. A second signal processor having a second adaptive filter that generates a second control signal based on a second reference signal related to a frequency component is configured to switch control based on a road surface input detected by a road surface input detector. Therefore, optimal noise reduction control can be performed according to road surface conditions.

  In this case, more specifically, the switch includes an error signal switch (SW1) that switches input / non-input of the error signal to the second signal processor, and a second reference regarding the second frequency component. A reference signal switch (SW4) that switches a signal to a third reference signal related to a third frequency component that is amplified when the first control signal is output, and an output destination of the second control signal is the second phase. A phase adjuster switch (SW3) for switching from the adjuster to the first phase adjuster, and based on the road surface input, the error signal switch, the reference signal switch, and the phase adjustment switch What is necessary is just to carry out switching control of the device.

  For example, when the first frequency component is 40 Hz, the second frequency component is 70 Hz, and the third frequency component is 50 Hz, the road surface input detector detects that the running road corresponds to a soft road surface such as an asphalt paved road. 40 Hz and 70 Hz by operating the first signal processor and the second phase adjuster operating at 70 Hz in parallel with the first signal processor and the first phase adjuster. Noise components (road noise components) can be simultaneously reduced.

  Further, for example, as shown in FIG. 7, when the road surface input detector detects that the running road corresponds to a hard road surface such as a concrete paved road, the first signal processor generated by the first signal processor operating at 40 Hz is used. The 50 Hz sound increase component included in the control signal is extracted by the second signal processor 52 operated at 50 Hz, and the extracted 50 Hz sound increase component is subtracted from the first control signal by the first phase adjuster. Only the noise component (road noise component) of 40 Hz can be reduced by generating the canceling signal.

  According to this invention, optimal noise reduction control can be performed according to the road surface condition.

  Hereinafter, for convenience of understanding, first, A. The premise technique by the active vibration noise control apparatus for vehicles having one frequency (one frequency) will be described. Description will be made in the order of the embodiments of the present invention.

A. FIG. 1 is a block diagram showing a basic configuration of a vehicle active vibration noise control apparatus 10 of 1 frequency (first frequency f1 = 40 Hz). is there.

  FIG. 2 is a block diagram showing a detailed configuration of the vehicular active vibration noise control apparatus 10 shown in FIG.

  1 and 2, the vehicle active vibration noise control apparatus 10 basically outputs a first control signal Sc1 based on an error signal e1 converted into a digital signal by the A / D converter 35. The signal processor 51, the first phase gain adjuster 46 that adjusts the phase and gain of the first control signal Sc 1 to generate the first canceling signal Scp 1, and the first analog signal generated by the D / A converter 37. Residual vibration noise due to interference between the first canceling sound and road noise at the evaluation point of the vehicle interior space 4 and a speaker 8 as a canceling sound output device that outputs the canceling signal Scp1 to the vehicle interior space 4 as the first canceling sound. And a microphone 6 as an error signal detector that detects the error signal e1. A portion obtained by removing the speaker 8 and the microphone 6 from the vehicle active vibration noise control device 10 is referred to as an active vibration noise control device {ANC (Active Noise Controller)} 18.

  The first signal processor 51 includes a subtracter (subtractor) 20 and a first adaptive notch filter 32.

  The first adaptive notch filter 32 generates a first reference signal r1 relating to a component of the first frequency f1 of the road noise, and a first control signal Sc1 based on the first reference signal r1. Based on the first adaptive filter 33 to be generated and the signal ed1 (ed1 = e1-Sc1) obtained by subtracting the first control signal Sc1 one sample before delayed by the one-sample time delay unit 36 from the error signal e1. The first filter coefficient updater 39 sequentially updates the first filter coefficient W1 of the one adaptive filter 33.

  As shown in FIG. 2, the first reference signal generator 26 shown in FIG. 1 generates a cosine wave signal cos (2πf1t) having a first frequency f1 of road noise and each being a reference signal. And a sine wave signal generator 24 for generating a sine wave signal sin (2πf1t).

  The first adaptive filter 33 shown in FIG. 1 includes a 1-tap adaptive filter 28 that outputs a cosine wave signal cos (2πf1t) multiplied by a filter coefficient A and a sine wave signal sin (2πf1t), as shown in FIG. It consists of a 1-tap adaptive filter 30 that outputs over a coefficient B, and an adder 31 that outputs an addition signal of A × cos (2πf1t) + B × sin (2πf1t) as a control signal Sc1.

  As shown in FIG. 2, the first filter coefficient updater 39 shown in FIG. 1 is supplied with a cosine wave signal cos (2πf1t) and a sine wave signal sin (2πf1t), and is a signal delayed by one sample time. ed1 is supplied, and the filter coefficients A and B of the 1-tap adaptive filters 28 and 30 are set based on an adaptive control algorithm such as the LMS (Least Mean Square) algorithm, which is a kind of steepest descent method, so that the signal ed1 becomes a minimum value. It consists of filter coefficient updaters 38 and 40 for updating.

As shown in FIG. 2, the first phase gain adjuster 46 shown in FIG. 1 includes a delay unit (Z ^−N ) 34 having an N sample time delay that operates as a phase shifter, and a gain connected in series to this. The control signal Sc1 supplied from the first signal processor 51 (the first adaptive notch filter 32) is predetermined by the delay device 34. And the amplitude is adjusted by the gain adjuster 44 and output as the first cancellation signal Scp1.

  Here, the phase delay amount θ1 that needs to be set in the delay unit 34 constituting the first phase gain adjuster 46 will be described. In order to make the road noise zero at the evaluation point where the microphone 6 is located, the phase difference between the first canceling sound and the road noise has a phase difference (reverse phase) of 180 ° at the evaluation point. And having the same amplitude. That is, regarding the phase difference, from the input point (position) of the microphone 6, the A / D converter 35, the first signal processor 51 (the subtractor 20, the first adaptive notch filter 32), the first phase gain adjuster 46, D It is necessary that the phase delay amount of the sine wave corresponding to the frequency f1 = 40 Hz of the road noise reaching the microphone 6 through the A / A converter 37, the speaker 8, and the vehicle interior space 4 is 180 °. A fixed value may be set in 34 so that the phase delay amount is 180 °.

  Next, the gain amount set in the gain adjuster 44 constituting the first phase gain adjuster 46 will be described. This gain amount can be considered in the same manner as the phase delay. In this case, the value may be set to a value (fixed value) that compensates for the amount of attenuation of the canceling sound in the route from the speaker 8 through the vehicle interior space 4 to the microphone 6.

  The operation of the vehicular active vibration noise control apparatus 10 including the first phase gain adjuster 46 configured as described above will be described with reference to FIG.

  In the microphone 6, residual noise due to interference between the road noise and the first canceling sound is detected as an error signal, and this error signal is converted into an error signal e1 of a digital signal by the A / D converter 35. The error signal e1 is supplied to the subtracted input terminal of the subtracter 20.

  The first adaptive notch filter 32 performs an operation of determining the filter coefficient W1 of the first adaptive filter 33 so that the signal ed1 that is a signal output from the subtracter 20 and input to the one-sample time delay unit 36 has a minimum value. As a result, the control signal Sc1 having the same amplitude and phase as the error signal e1 of the road noise frequency f1 is generated at the subtraction input terminal of the subtracter 20.

  That is, the first signal processor 51 having the first adaptive notch filter 32 functions as a notch filter having the center frequency f1 on the output side of the subtracter 20 (the generation point of the signal ed1) with respect to the error signal e1. It functions as a band-pass filter (BPF) having a center frequency f1 on the subtracted input side (the generation point of the control signal Sc1).

  FIG. 3 shows a passband frequency characteristic 250 at the generation point of the control signal Sc1 of the first adaptive notch filter 32. It can be seen from the passband frequency characteristic 250 that the filter operates as a steep bandpass filter (bandpass filter) at the center frequency f1 (f1 = 40 Hz). The steepness can be changed by adjusting a step size parameter which is a control parameter.

In this case, the update formula of the filter coefficient W1 is given by the following formula (1), where the step size parameter is μ.
W1 (n + 1) = W1 (n) −μ · ed1 (n) · cos (2πf1 × n × t) (1)

  The control signal Sc1 generated by the first adaptive notch filter 32 is turned into a cancellation signal Scp1 whose phase and amplitude are adjusted by the first phase gain adjuster 46. The canceling signal Scp1 is output as a first canceling sound from the speaker 8 and interferes with the road noise as a canceling sound having a reverse phase and the same amplitude as that of the road noise at the input point of the microphone 6 to cancel the road noise.

  The above explanation is as follows. This is a description of the premise technology of the vehicle active vibration noise control apparatus 10 for one frequency (one frequency). An embodiment of the present invention will be described.

B. Description of Embodiments of the Invention FIG. 4 shows a configuration of an active vibration noise control device 100 for a vehicle according to an embodiment of the present invention.

  A vehicle body 314 of the vehicle 300 is suspended on a road (load) 316 via a suspension including wheels 302 and a damper 304.

  An acceleration sensor unit 306 as a road surface input detector that detects acceleration in the vertical direction (pitching direction) of the vehicle body 314 is attached to a connection portion between the damper 304 and the vehicle body 314. The acceleration sensor unit 306 is provided with a threshold value, and outputs a road surface input detection signal Ss, which is a binary signal that is low level L when the vertical acceleration is below the threshold value and high level H when the acceleration is above the threshold value. .

  When the vehicle 300 is traveling on a soft road such as an asphalt paved road as compared with a case where the vehicle 300 is traveling on a hard road such as a concrete paved road, the acceleration sensor constituting the acceleration sensor unit 306 is used. The detected vertical acceleration is smaller than the threshold value. In this case, a road surface input detection signal Ss which is identified as an asphalt paved road and becomes a low level (L) is output. When the vertical acceleration is larger than the threshold value, the road surface input detection signal Ss which is identified as a concrete paved road and becomes a high level (H) is output.

  Based on the switching table 400 of FIG. 5, the error signal switch SW1 constituting the active vibration noise control device (ANC) 18A, the first control, according to the level of the road surface input detection signal Ss output from the acceleration sensor unit 306. The signal switch SW2, the phase adjustment switch SW3, and the reference signal switch SW4 are switched.

  The switching positions of the switches SW1 to SW4 depicted in FIG. 4 indicate the switching positions when the level of the road surface input detection signal Ss is a low level L corresponding to traveling on an asphalt paved road (see also FIG. 5). .

  In FIG. 4, a microphone 6 is attached to the center of the roof in the vehicle interior space 4. The speaker 8 is attached to the kick panel portion of the front seat. In FIG. 4, the canceling sound and the road noise are schematically drawn by arrows.

  The vehicle active vibration noise control apparatus 100 of FIG. 4 has a first phase gain adjustment in which the delay amount and the gain amount are set to the first frequency f1 = 40 Hz in the vehicle active vibration noise control apparatus 10 shown in FIG. The second phase gain adjuster 146 in which the delay amount and gain amount are set to the second frequency f2 = 70 Hz and the second signal processor 151 are connected in series to the series circuit of the detector 46 and the first signal processor 51. The circuit is connected in parallel.

  In this case, the error signal e1 output from the A / D converter 35 is supplied to the subtracted input terminal of the subtracter 20 constituting the first signal processor 51, and the error signal switch SW1 is in the ON state. At this time, the signal is supplied to the subtracted input terminal of the subtractor 120 constituting the second signal processor 151 via the error signal switch SW1.

  The subtracter 20 supplies a signal ed1 (ed1 = e1−Sc1) obtained by subtracting the first control signal Sc1 from the error signal e1 to the 1-sample time delay unit 36 constituting the first adaptive notch filter 32.

  Since the first control signal switch SW2 is in the OFF state and the error signal switch SW1 is in the ON state, the subtracter 120 generates the signal ed2 (ed2 = e1-Sc2) obtained by subtracting the second control signal Sc2 from the error signal e1. The two adaptive notch filters 132 are supplied to a one sample time delay unit 136.

  The second signal processor 151 includes a second reference signal generator 126 that generates a second reference signal r2 related to a second frequency component of road noise (here, a second frequency f2 of 70 Hz), and a first control signal Sc1 A third reference signal generator 127 that generates a third reference signal r3 relating to a third frequency component (here, a third frequency f3 of 50 Hz) that is increased when output, and the level of the road surface input detection signal Ss Accordingly, the reference signal switch SW4 that selectively switches and outputs the second reference signal r2 or the third reference signal r3, and the second control signal Sc2 is generated based on the second reference signal r2 or the third reference signal r3. The second adaptive filter 133, the second filter coefficient updater 139 that sequentially updates the second filter coefficient W2 of the second adaptive filter 133, the subtractor 120 described above, and the signal ed2 are converted into one sample. Consisting of one sample time delay unit 136 and outputting the second filter coefficient updater 139 by Le time delay.

  The first control signal Sc1 is supplied to the first phase gain adjuster 46 through the subtracted input terminal of the subtractor 318. When the phase adjustment switch SW3 is switched to the second phase gain adjuster 146 side (the illustrated side), the second control signal Sc2 is supplied to the second phase gain adjuster 146 as it is. When the phase adjustment switch SW3 is switched to the subtracter 318 side, the second control signal Sc2 is subtracted from the first control signal Sc1 through the subtracting input terminal of the subtractor 318 (Sc1-Sc2), and the first It is supplied to the phase gain adjuster 46.

  In the switching state of FIG. 4, the first and second cancellation signals Scp1 and Scp2 whose phases and gains are adjusted by the first and second phase gain adjusters 46 and 146 are added to the adder 152 as D / A signals. It is supplied to the converter 37.

  In the switching state of FIG. 7, the first cancellation signal Scp <b> 1 whose phase and gain are adjusted only by the first phase gain adjuster 46 (FIG. 7) is supplied to the D / A converter 37 through the adder 152.

  The output signal of the adder 152 is output as a canceling sound through the D / A converter 37 and the speaker 8, and a residual error signal in which the canceling sound obtained at the input point of the microphone 6 interferes with the road noise is an A / D converter. 35 is output as an error signal e1.

  Next, the operation in the switching state of FIG. 4 of the vehicular active vibration noise control apparatus 100 configured as described above will be described.

  When the vehicle 300 is traveling on a soft road surface 316 such as an asphalt paved road, the damper 304 does not vibrate so much that the road surface detection input signal Ss output from the acceleration sensor unit 306 is at a low level L.

  As shown in the switching table 400, when the road surface detection input signal Ss is at the low level L, the error signal switch SW1 is in the ON state, the first control signal switch SW2 is in the OFF state, and the phase adjustment switch SW3 is in the second phase. The reference signal switch SW4 is switched to the second reference signal generator 126 side on the gain adjuster 146 side (switching state of SW1 to SW4 shown in FIG. 4).

  In this case, the first signal processor 51 whose output is connected to the input of the first phase gain adjuster 46 that outputs the first cancellation signal Scp1, and the second phase gain adjuster 146 that outputs the second cancellation signal Scp2. The error signal e1 is supplied to the second signal processor 151 whose output is connected to the input.

  At this time, the first signal processor 51 operates so as to minimize the error signal ed1 (ed1 = e1−Sc1). Therefore, the first signal processor 51 operates as a bandpass filter having a center frequency of 40 Hz, and the first control signal Sc1 is In the error signal e1, a component having passed 40 Hz as a center frequency is passed, and the phase and gain are adjusted such that this component has the opposite phase and the same amplitude at the position of the microphone 6 by the first phase gain adjuster 46. 1 cancellation signal Scp1.

  On the other hand, the second signal processor 151 operates so as to minimize the error signal ed2 (ed2 = e1-Sc2), so that the second signal processor 151 operates as a band-pass filter having a center frequency of 70 Hz. In the error signal e1, the second component is obtained by adjusting the phase and gain so that the component passes through 70 Hz as the center frequency, and this component has the opposite phase and the same amplitude at the position of the microphone 6 by the second phase gain adjuster 146. The cancellation signal Scp2 is used.

  The first canceling signal Scp1 and the second canceling signal Scp2 are added by the adder 152, and the added signal is output as a canceling sound through the D / A converter 37 and the speaker 8, whereby the microphone 6 arranged at the evaluation point In the position of, road noise components of 40 Hz and 70 Hz are simultaneously reduced.

  As described above, when the acceleration sensor unit 306 as a road surface input detector detects that the vehicle 300 is traveling on a soft road 316 such as an asphalt paved road, the first signal processor 51 and the first signal processor 51 operating at 40 Hz are used. By operating the series circuit of the second signal processor 151 and the second phase gain adjuster 146 operating at 70 Hz in parallel with the series circuit of the one phase gain adjuster 46, noise of 40 Hz and 70 Hz is obtained. Components can be reduced simultaneously.

  FIG. 6 shows a case where the active vibration noise control device 18A is not operated {ANC (Active Noise Controller) is OFF. } Characteristic 320 (solid line) and when the active vibration noise control device 18 is operated {referred to as when the ANC is ON. } Is an explanatory diagram of an effect indicating a characteristic 322 (dotted line). In the characteristic 322 when the ANC is ON, the sound increases slightly in the vicinity of 50 Hz, but it can be seen that the noise of the first peak at 40 Hz and the second peak at 70 Hz is significantly reduced.

  On the other hand, when the vehicle 300 is traveling on a hard road surface 316 such as a concrete paved road, the vibration of the damper 304 increases, and the road surface detection input signal Ss output from the acceleration sensor unit 306 is at a high level H. Become.

  As shown in the switching table 400, when the road surface detection input signal Ss is at the high level H, the error signal switch SW1 is in the OFF state, the first control signal switch SW2 is in the ON state, and the phase adjustment switch SW3 is the subtractor 318. The reference signal switch SW4 is switched to the third reference signal generator 127 side.

  FIG. 7 shows a block diagram of the vehicular active vibration noise control apparatus 100 depicting the switching positions of SW1 to SW4 at this time.

  In this case, the error signal e1 is input only to the first signal processor 51. At this time, since the first signal processor 51 operates so that the error signal ed1 is minimized, the first signal processor 51 operates as a bandpass filter having a center frequency of 40 Hz, and the first control signal Sc1 is 40 Hz in the error signal e1. The first control signal Sc includes a 50 Hz component that is generated reactively when it is reduced around 40 Hz and becomes a sound increase component.

  The 40 Hz component and the first control signal Sc1 including the 50 Hz component are supplied to the subtraction input terminal of the subtractor 120 through the switch SW2. In this case, since the error signal e1 having a 40 Hz component as a main component is supplied to the subtracted input terminal of the subtracter 120, the 40 Hz component is canceled out and the 50 Hz component remains in the first control signal Sc1. However, the second signal processor 151 having the second adaptive notch filter 132 to which the 50 Hz reference signal r3 is supplied from the third reference signal generator 127 through the switch SW4 is a band on the output side of the second adaptive filter 133. Since the second control signal Sc2 functions as a pass filter, the second control signal Sc2 is approximately a 50 Hz component that is the sound increase component, and the second control signal Sc2 including the 50 Hz sound increase component is subtracted by the subtractor 318 through the switch SW3. Supplied to the input terminal.

  In the subtractor 318, a signal obtained by subtracting the second control signal Sc2 from the first control signal Sc1, that is, the first control signal Sc1 having a component centered on 40 Hz and a component centered on 50 Hz is centered on 50 Hz. Only the component centered at 40 Hz to which the second control signal Sc2 having the component is subtracted is extracted and supplied to the first phase gain adjuster 46.

  The first phase gain adjuster 46 outputs a first cancellation signal Scp1 in which the phase and gain are adjusted so that the component centered at 40 Hz has the opposite phase and the same amplitude at the point of the microphone 6.

  The first canceling signal Scp1 is output as a canceling sound through the speaker 8 through the D / A converter 37, so that a 40-Hz road noise component is reduced at the position of the microphone 6 arranged at the evaluation point.

  Thus, when the acceleration sensor unit 306 as a road surface input detector detects that the vehicle 300 is traveling on a hard road surface 316 such as a concrete paved road, the noise reduction operation is performed at 40 Hz, but the sound is increased at 50 Hz. The first control signal Sc1, which is the output of the first signal processor 51 that generates the component, is processed by the second signal processor 151 that operates as a bandpass filter having a center frequency of 50 Hz, and consists of the extracted 50 Hz component. Since the signal obtained by subtracting the second control signal Sc2 from the first control signal Sc1 is supplied to the first phase gain adjuster 46, only the 40 Hz component can be reduced without increasing the 50 Hz component. .

  FIG. 8 is an explanatory diagram of the effect showing the characteristics 324 (solid line) when ANC is OFF and the characteristics 328 (dotted line) when ANC is ON.

  A one-dot chain line characteristic 326 is a characteristic when the ANC is ON when the second signal processor 151 illustrated in FIG. 7 does not exist.

  In contrast to the one-dot chain line characteristic 326, the dotted line characteristic 328 at the time of ANC ON when the second signal processor 151 shown in FIG. 7 is present has almost no sound increase near 50 Hz, and the peak at 40 Hz is remarkably reduced. You can see that.

  According to the above-described embodiment, the vehicle active vibration noise control device 100 that minimizes road noise generated while traveling on an asphalt pavement surface or a concrete pavement surface is provided. That is, while traveling on an asphalt pavement surface, the first signal processor 51 operating at 40 Hz and the second signal processor 52 operating at 70 Hz are operated in parallel to reduce road noise of 40 Hz and 70 Hz components, While traveling on a concrete pavement surface, a 50 Hz sound increase component included in the first control signal generated by the first signal processor operating at 40 Hz is extracted by the second signal processor 52 operating at 50 Hz. Then, by subtracting the extracted 50 Hz sound increase component from the first control signal and generating the cancellation signal Scp1 by the first phase gain adjuster 46, only the 40 Hz noise component (road noise component) is effectively reduced. can do.

  Thus, according to this embodiment, optimal noise reduction control can be performed according to road surface conditions.

  In the vehicle active vibration noise control apparatus 100 shown in FIG. 4, the first control signal switch SW <b> 2 may be always on. This stabilizes the control.

1 is a block diagram showing a basic configuration of a 1-frequency vehicle active vibration noise control apparatus which is a prerequisite technology of the present invention; FIG. It is a block diagram which shows the detailed structure of the active vibration noise control apparatus for vehicles shown in FIG. It is explanatory drawing which shows the passband frequency characteristic in the generation | occurrence | production point of the control signal of a 1st adaptive notch filter. 1 is a block diagram showing a configuration of an active vibration noise control apparatus for a vehicle according to an embodiment of the present invention. It is a switching table figure which shows the switching state of the switch switched according to road surface input. It is explanatory drawing of the effect which shows the characteristic at the time of ANC OFF during driving | running | working on a soft road surface, and the characteristic at the time of ANC ON. It is a block diagram which shows the structure of the active vibration noise control apparatus for vehicles which concerns on one Embodiment of this invention on which the switching position of each switching device during the driving | running | working of a hard road surface was drawn. It is explanatory drawing of the effect which shows the characteristic at the time of ANC OFF during driving | running | working on a hard road surface, and the characteristic at the time of ANC ON. It is a block diagram which shows the structure of the active vibration noise control apparatus for vehicles which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 6 ... Microphone 8 ... Speaker 26 ... 1st reference signal generator 33 ... 1st adaptive filter 39 ... 1st filter coefficient updater 46 ... 1st phase gain adjuster 51 ... 1st signal processor 52 ... 2nd signal processor DESCRIPTION OF SYMBOLS 100 ... Active vibration noise control apparatus for vehicles 126 ... 2nd reference signal generator 127 ... 3rd reference signal generator 133 ... 2nd adaptive filter 139 ... 2nd filter coefficient updater 146 ... 2nd phase gain adjuster 151 ... Second signal processor 306 ... acceleration sensor unit

Claims (2)

A first reference signal generator for generating a first reference signal for a first frequency component of road noise;
A first adaptive filter that generates a first control signal based on the first reference signal;
A first filter coefficient updater for sequentially updating the first filter coefficient of the first adaptive filter;
A first signal processor comprising:
A second reference signal generator for generating a second reference signal for a second frequency component of road noise;
A second adaptive filter that generates a second control signal based on the second reference signal;
A second filter coefficient updater for sequentially updating a second filter coefficient of the second adaptive filter;
A second signal processor comprising:
A first phase adjuster for adjusting a phase of the first control signal and generating an offset signal;
A second phase adjuster for adjusting the phase of the second control signal and generating an offset signal;
A canceling sound output device that outputs the canceling signal as a canceling sound;
An error signal detector for detecting residual vibration noise due to interference between the canceling sound and the road noise at an evaluation point as an error signal;
With
The first filter coefficient updater updates the first filter coefficient based on a sum signal of the error signal and the first control signal one sample before,
The second filter coefficient updater updates the second filter coefficient based on an addition signal of the error signal and the second control signal one sample before. In the vehicle active vibration noise control device,
A road surface input detector for detecting an input from the road surface to the vehicle;
A switch for switching the control of the second signal processor based on the road surface input;
An active vibration noise control device for a vehicle, comprising: The active vibration noise control device for a vehicle according to claim 1,
The switch is
An error signal switch for switching input / non-input of the error signal to the second signal processor;
A reference signal switch that switches a second reference signal related to the second frequency component to a third reference signal related to a third frequency component that is amplified when the first control signal is output;
A phase adjuster switch for switching the output destination of the second control signal from the second phase adjuster to the first phase adjuster;
And consist of
An active vibration noise control device for a vehicle, wherein the error signal switching device, the reference signal switching device, and the phase adjustment switching device are switched based on the road surface input.

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