JP5214340B2 - Active vibration and noise control system for vehicles - Google Patents

Description

  The present invention relates to an active vibration noise control system for a vehicle including a road noise control device that cancels the road noise by causing a canceling sound having a phase opposite to that of the road noise to interfere with road noise heard in a vehicle interior.

  The vibration of the wheel received from the road (road) while the vehicle is traveling is transmitted to the vehicle body via the suspension, and is excited by the acoustic resonance characteristic of the closed space such as in the passenger compartment, and peaks at a frequency of about 40 [Hz]. Active vibration noise control that cancels out a road noise having a noise (a “go” sound, also called drumming noise) with an offset sound having an opposite phase to the road noise at an evaluation point (listening point) where the microphone is disposed ( An ANC (Active Noise Control) device has been proposed (Patent Document 1).

  Further, various rotating bodies such as an engine crank, a transmission main shaft, a counter shaft, and a propeller shaft are present in the vehicle in connection with the operation of the engine. The rotational frequency of these rotating bodies varies depending on the vehicle speed and the like. Due to the rotation of the rotating body, noise related to the rotational frequency is generated in the passenger compartment (referred to as engine noise, engine noise or vibration noise of the rotating body for the sake of convenience). A vehicle interior noise reduction system that simultaneously reduces the engine noise and the road noise at the evaluation point has also been proposed (Patent Document 2).

JP 2000-280831 A JP-A-7-104767

  By the way, the inventors of this application, as shown in FIG. 4, in the active vibration noise control system that performs road noise silencing control, the sensitivity function when trying to reduce road noise at a frequency of 40 [Hz]. The characteristic 100 is attenuated by, for example, about -10 [dB] in the vicinity of the frequency 40 [Hz], and becomes a road noise silencing region in the vicinity of the frequency 40 [Hz]. In the vicinity of 55 [Hz], the gain is increased by about 3 dB, and a phenomenon of a sound increase region (negative region) caused by road noise suppression control (road noise frequency sound) is found.

  In this case, in the region where the rotational frequency of the engine booming noise overlaps with the frequency of the negative region of the road noise described above (near 25 [Hz] and 55 [Hz]), the sound with the overlapping frequency increases. This causes the inconvenience that the engine booming sound feels as if it has been increased.

  Furthermore, in a composite type vehicle interior active vibration noise control system equipped with engine noise suppression control in addition to road noise suppression control, the rotational frequency of engine noise is the frequency in the negative region of road noise described above. There is a disadvantage that the combined vibration and noise control becomes unstable in the region overlapping with.

  The present invention has been made in consideration of such inconveniences, and the rotational frequency of the rotating body related to the operation of the engine overlaps the frequency of the sound increase region (negative region) caused by road noise silencing control. This makes it possible to alleviate inconveniences such as feeling that the engine booming sound has been boosted on the contrary, as well as complex vibration noise control (road noise silencing control and engine silencing noise suppression) It is an object of the present invention to provide an active vibration and noise control system for a vehicle that enables stable control.

  Further, in the present invention, even if the rotational frequency of the rotating body related to the operation of the engine overlaps with the frequency of the sound increase region (negative region) caused by the noise suppression control of road noise, On the other hand, an object of the present invention is to provide an active vibration noise control system for a vehicle that makes it possible to alleviate inconveniences such as feeling that the sound has been increased.

  An active vibration noise control system for a vehicle according to the present invention generates a first reference signal related to the rotating body based on the rotating frequency detector for detecting the rotating frequency of the rotating body mounted on the vehicle and the rotating frequency. A rotating body vibration noise control device that outputs a first canceling signal for canceling vibration noise of the rotating body based on the first reference signal, and road noise A vehicle having a second reference signal generator that generates a second reference signal, and a road noise control device that outputs a second cancellation signal for canceling the road noise based on the second reference signal In the active vibration noise control system, the road noise control device includes a gain adjuster that adjusts a gain for amplifying the second cancellation signal, and the gain of the gain adjuster Rotation frequency, characterized in that the lowered when a predetermined frequency.

  According to the present invention, the gain adjuster that amplifies the second canceling signal for canceling the road noise when the rotational frequency of the rotating body related to the operation of the engine mounted on the vehicle reaches a predetermined frequency. Therefore, the increased sound volume at the predetermined frequency can be mitigated.

  In this case, the predetermined frequency is set to a frequency in the sound increase frequency region that is increased by the output of the second canceling signal for canceling the road noise, so that the rotating body related to the operation of the engine To mitigate inconveniences such as feeling that the engine noise is increased even if the rotation frequency overlaps the frequency of the sound increase area (negative area) caused by road noise suppression control. In addition, composite vibration noise control (road noise silencing control and engine muffle noise silencing control) can be performed in a coordinated and stable manner.

  It should be noted that coordinated vibration noise control can be performed more stably by lowering the gain of the gain adjuster so that the increased sound volume of the frequency within the increased sound frequency region is below a predetermined increased sound volume.

  The vehicle active vibration noise control system according to the present invention further includes a reference signal generator that generates a reference signal related to road noise, and outputs a canceling signal for canceling the road noise based on the reference signal. An active vibration noise control system for a vehicle, comprising: a road noise control device that detects a rotation frequency of a rotating body mounted on the vehicle; and the road noise control device includes: And a gain adjuster for adjusting a gain for amplifying the gain, wherein the gain of the gain adjuster is lowered when the rotation frequency reaches a predetermined frequency.

  According to the present invention, the gain adjuster that amplifies the second canceling signal for canceling the road noise when the rotational frequency of the rotating body related to the operation of the engine mounted on the vehicle reaches a predetermined frequency. Therefore, the increase in the predetermined frequency can be mitigated.

  In this case, the predetermined frequency is set to a frequency in the sound increase frequency region that is increased by the output of the second canceling signal for canceling the road noise, so that the rotating body related to the operation of the engine To mitigate inconveniences such as feeling that the engine noise is increased even if the rotation frequency overlaps the frequency of the sound increase area (negative area) caused by road noise suppression control. Can do.

  Even in this case, the sound volume increase can be controlled by lowering the gain of the gain adjuster so that the sound volume increase in the frequency range of the sound increase frequency is not more than a predetermined sound increase volume.

  The rotating body related to the operation of the engine is at least one of an engine crank, a transmission main shaft, a counter shaft, a drive shaft, or a propeller shaft.

  According to the present invention, even if the rotational frequency of the rotating body related to the operation of the engine is a region overlapping the frequency of the sound increase region (negative region) caused by road noise silencing control, On the other hand, it is possible to alleviate inconveniences such as feeling that the sound has been increased, and to perform composite vibration noise control (road noise mute control and engine muffle noise mute control) in a coordinated and stable manner.

  Further, according to the present invention, even if the rotational frequency of the rotating body related to the operation of the engine is a region where the frequency of the sound increase region (negative region) caused by the noise suppression control of the road noise overlaps, However, it is possible to alleviate inconvenience such as feeling that the sound has been increased.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a basic configuration of an active vibration noise control system 10 for a vehicle according to an embodiment of the present invention.

  The vehicle active vibration noise control system 10 mounted on a vehicle basically generates a first canceling signal Sc1 for generating a canceling sound for canceling an engine noise (engine noise). A generation unit 11 (rotating body vibration noise control device), and a second cancellation signal generation unit 12 (road noise control device) that generates a second cancellation signal Sc2 for generating cancellation noise that cancels road noise. , Engine muffler noise and road noise mute control are coordinated.

  The first and second cancellation signal generation units 11 and 12 are configured to include a computer, and the CPU realizes various functions by executing programs stored in a memory such as a ROM based on various inputs. It also operates as a unit (function implementation means).

  A microphone (error signal detector) 22 is provided in the vehicle interior space 24 for detecting residual noise caused by interference between engine noise, road noise, and canceling noise as an error signal e at evaluation points (evaluation position, listening point). It has been.

  Based on the cancellation signal Sc3 (Sc3 = Sc1 + Sc2) obtained by adding the adder 50 and combining the first cancellation signal Sc1 and the second cancellation signal Sc2 supplied from the D / A converter 28. A speaker (cancelling sound output device) 26 that outputs the canceling sound for canceling noise to the vehicle interior space 24 is also provided in the vehicle interior space 24.

  The error signal e output from the microphone 22 is converted into an error signal e of a digital signal through the A / D converter 30 and supplied as an input signal to the first cancellation signal generation unit 11 and the second cancellation signal generation unit 12.

  The first cancellation signal generation unit 11 is a circuit using a feedforward type filtered-X LMS algorithm.

  The first canceling signal generation unit 11 is a rotation constituted by a frequency counter that detects a rotation frequency fe of an engine crank (rotary body) from an engine rotation signal (engine pulse) supplied from a fuel injection ECU (FIECU) (not shown). A frequency detector 42; a first reference signal generator 31 for generating a first reference signal Sr1 {cosine wave signal cos (2πfet) and sine wave signal sin (2πfet)} having a frequency of the rotational frequency fe; The first adaptive filter 46 that generates the first cancellation signal Sc1 by adjusting the phase and amplitude of the signal Sr1, and the adder 50 → D / A converter 28 → speaker 26 → car from the output terminal of the first cancellation signal Sc1 The input terminal of the first cancellation signal generator 11 through the indoor space 24 (sound field) → microphone 22 → A / D converter 30 (filter coefficient update described later) Rotation frequency fe (rotation frequency fe varies depending on the engine rotation signal) up to the input end of the measuring device 48, so that simulated transfer characteristics C ^ and the like simulating sound transfer characteristics at each rotation frequency fe are set. A reference signal generator (filter) 44 that filters the one reference signal Sr1 to generate the first reference signal r1, an adaptive control algorithm that supplies the reference signal r1 and the error signal e, and minimizes the error signal e, for example, And a filter coefficient updater (algorithm calculator) 48 that updates the filter coefficient W1 of the first adaptive filter 46 based on an LMS (Least Mean Square) algorithm that is a kind of steep descent method.

  On the other hand, the second cancellation signal generation unit 11 includes an adaptive notch filter 111 that functions as a bandpass filter and a simulated transfer characteristic unit 112.

  The adaptive notch filter 111 is fixed according to the vehicle type, for example, a second reference signal Sr2 synchronized with a road noise frequency fd [Hz] of about 40 [Hz] {cosine wave signal cos (2πfdt) and sine wave signal sin (2πfdt). }, And a second second cancellation signal substantially equal to the amplitude and phase of the component of the road noise frequency fd in the error signal e at the reduction input terminal of the subtractor 33 from the second reference signal Sr2. A second adaptive filter 36 for generating Sco2, a second reference signal Sr2, and a signal (e-Sco2) obtained by subtracting the original second cancellation signal Sco2 from the error signal e delayed by the one-sample delay unit 35. The second adaptive fill algorithm based on an adaptive control algorithm in which the supplied signal (e-Sco2) is minimized, for example, an LMS algorithm which is a kind of steepest descent method And a filter coefficient updater (algorithm calculator) 38 for updating the filter coefficient W2 of the filter 36.

  The simulated transfer characteristic unit 112 includes a phase shifter 37, a gain adjuster 39, and a frequency determiner 40. In the phase shifter 37, a phase shift amount is set in advance such that the phase of the input original second cancellation signal Sco2 is opposite to the road noise phase at the position of the microphone 22. In the gain adjuster 39, a gain G2 is set such that the amplitude of the original second cancellation signal Sco1 phase-shifted by the phase shifter 37 approaches an equal amplitude with respect to the amplitude of the road noise at the position of the microphone 22. .

  As described above, in the second cancellation signal generation unit 12, the phase of the cancellation noise of the road noise at the position of the microphone 22 is opposite to the phase of the road noise having a frequency of about 40 [Hz] in order to cancel the road noise. Set to be in phase.

  However, because of this setting, as shown in FIG. 4, at a frequency in the vicinity of a frequency of 25 [Hz] and a frequency in the vicinity of a frequency of 55 [Hz], mute control of road noise (road noise frequency sound) at a frequency of 40 [Hz]. Note that a frequency region in which the sensitivity function characteristic 100 becomes positive inevitably occurs due to a sound increase region (negative region) caused by the above.

  Therefore, in order to suppress (relax) the increase in the volume of the frequency sound in the negative region, the rotational frequency fe detected by the rotational frequency detector 42 is set to the negative region frequency (above 25 [Hz] and 55 [Hz]. Frequency] 40 for controlling the gain adjuster 39 to decrease the gain G2 so that the amplitude of the second cancellation signal Sc2 becomes small. Connected to the adjustment port (gain setting port). The frequency determiner 40 receives the rotation frequency fe.

  Next, basically, the operation of the vehicular active vibration noise control system 10 according to this embodiment configured as described above will be described.

  As described above, the second cancellation signal generator 12 of the active vibration noise control system 10 for a vehicle uses the gain adjuster through the frequency determiner 40 according to the predetermined frequency of the rotation frequency fe detected by the rotation frequency detector 42. The gain G2 of 39 is adjusted.

  As shown in FIG. 2, the adjustment amount of the gain G2 corresponding to the rotation frequency fe executed by the frequency determiner 40 constituting the second cancellation signal generation unit 12 is set to a predetermined value by the frequency determiner 40. When it is determined that the frequency is a frequency, specifically, when it is determined that the sensitivity function characteristic 100 of the solid line is present in the vicinity of the sound increase region 25 [Hz] and 55 [Hz] where the value is positive, the frequency determiner 40 is The gain G2 of the gain adjuster 39 is lowered so that the sensitivity function characteristic 100 indicated by the normal solid line becomes the sensitivity function characteristic 102 indicated by the dotted line. Thus, on the sensitivity function characteristic 102, the gain of about +3 [dB] is about +1 in the vicinity of the sound increase region 25 [Hz] and 55 [Hz] where the sensitivity function characteristic 100, which is the predetermined frequency, has a positive value. .5 [dB] and drop to about half. Note that the amount of decrease in the gain G2 can be determined to an optimum value in the simulation of the active vibration noise control system 10 or the state of mounting on the actual vehicle. The optimum value is a value that can mitigate inconveniences such as feeling that the engine noise is increased near the frequency 25 [Hz] and the frequency 55 [Hz]. The value is determined so that the (noise suppression control for road noise and the engine noise suppression control) can be stably performed in cooperation.

  In this way, if the gain G2 is lowered, even if the rotational frequency fe is in the vicinity of the frequency 25 [Hz] or the frequency 55 [Hz], the engine noise is increased based on the sensitivity function characteristic 102 of the second cancellation signal generation unit 12. The noise reduction control can be continued stably even if it feels like this.

  In addition, as the gain G2 of the gain adjuster 39 is lowered so that the sensitivity function characteristic 100 becomes the sensitivity function characteristic 102, when the rotation frequency fe is near fe = 40 [Hz], the noise reduction level of the road noise is −10. Although it is about half from [dB] to -5 [dB], a predetermined silencing effect can be obtained.

  As described above, the vehicular active vibration noise control system 10 according to the above-described embodiment is a rotating body vibration noise control device for canceling engine noise, which is vibration noise related to a rotating body mounted on a vehicle. As a first cancellation signal generation unit 11 and a second cancellation signal generation unit 12 as a road noise control device for canceling road noise.

  The first cancellation signal generation unit 11 generates a first reference signal Sr1 related to the rotating body based on the rotating frequency detector 42 that detects the rotating frequency fe of the rotating body mounted on the vehicle and the rotating frequency fe. The filter coefficient of the first adaptive filter 46 is calculated by LMS so that the error signal e becomes zero based on the reference signal r1 obtained by filtering the first reference signal generator 31, the first reference signal Sr1, and the error signal e. And the first adaptive filter 46 that outputs a first cancellation signal Sc1 for canceling vibration noise of the rotating body based on the first reference signal Sr1.

The second cancellation signal generator 12 is a second reference signal generator 32 that generates a second reference signal Sr2 related to road noise, and the original second cancellation signal Sco2 is subtracted from the second reference signal Sr2 and the error signal e. The second adaptive type is performed by performing the LMS operation so that the signal before the one sample delay of the signal is supplied and the signal before the one sample delay of the signal obtained by subtracting the original second cancellation signal Sco2 from the error signal e becomes substantially zero value. An adaptive notch filter 111 including a filter coefficient updater 38 that determines a filter coefficient of the filter 36, and a simulated transfer characteristic unit 112 including a phase shifter 37, a gain adjuster 39, and a frequency determiner 40 are provided.

  Then, the rotational frequency fe of the rotating body related to the operation of the engine mounted on the vehicle is increased by a predetermined frequency, in this embodiment, the output of the second cancellation signal Sc2 for canceling road noise. By setting the frequency within the sound frequency region (see FIG. 2), the rotational frequency fe of the rotating body related to the operation of the engine overlaps the frequency of the sound increase region (negative region) caused by road noise silencing control. Even in the area, it is possible to alleviate inconveniences such as feeling that the engine noise is increased on the contrary, and combined vibration noise control (road noise suppression control and engine noise suppression control) Can be performed stably in cooperation.

  In addition, by reducing the gain G2 of the gain adjuster 39 so that the volume increase in the frequency within the sound increase frequency region is equal to or lower than a predetermined volume increase, for example, audible or not, cooperative vibration noise Control can be performed more stably.

  FIG. 3 is a block diagram showing the configuration of a vehicle active vibration noise control system 10A according to another embodiment.

  The vehicle active vibration noise control system 10A according to this other embodiment deletes the first cancellation signal generation unit 11 from the vehicle active vibration noise control system 10 of FIG. This configuration is left as the cancellation signal generation unit 12A.

  This vehicular active vibration noise control system 10A includes a reference signal generator 32A that generates a reference signal Sr related to road noise, and one sample delay of a signal obtained by subtracting the original second cancellation signal Sco from the reference signal Sr and the error signal e. The filter coefficient W of the adaptive filter 36 is obtained by performing an LMS operation such that the previous signal is supplied and the signal before the one-sample delay of the signal obtained by subtracting the original second cancellation signal Sco from the error signal e is approximately zero. An adaptive notch filter 111A including a filter coefficient updater 38 to be determined, and a simulated transfer characteristic unit 112A including a phase shifter 37, a gain adjuster 39A, and a frequency determiner 40 are provided.

  The rotational frequency fe of the rotating body related to the operation of the engine mounted on the vehicle is a predetermined frequency, in this embodiment, the sound increase frequency that is increased by the output of the cancellation signal Sc for canceling road noise. By reducing the gain G of the gain adjuster 39A by the frequency within the region, the rotational frequency fe of the rotating body related to the operation of the engine is the frequency of the sound increase region (negative region) caused by road noise silencing control. Even if the region overlaps with the engine, inconveniences such as feeling that the engine noise is increased on the contrary can be alleviated.

  Note that it is preferable to lower the gain G of the gain adjuster 39A so that the volume increase in the frequency within the sound increase frequency region is not more than a predetermined volume increase, for example, it is felt or not.

  In each of the above-described embodiments, the rotating body related to the operation of the engine may be at least one of an engine crank, a transmission main shaft, a counter shaft, a drive shaft, or a propeller shaft.

  Note that the present invention is not limited to the above-described embodiment, and various configurations are adopted based on the description in this specification, for example, when a wind noise canceling signal generation unit that flows on the surface of the vehicle body is provided. Of course you get.

1 is a block diagram showing a configuration of an active vibration noise control system for a vehicle according to an embodiment of the present invention. It is switching explanatory drawing of a sensitivity function characteristic. It is a block diagram which shows the structure of the active vibration noise control system for vehicles which concerns on other embodiment of this invention. It is explanatory drawing of the sensitivity function characteristic which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10A ... Vehicle active vibration noise control system 11 ... 1st cancellation signal production | generation part (rotary body vibration noise control apparatus)
12, 12A ... 2nd cancellation signal generation part (road noise control device)
22 ... Microphone 24 ... Vehicle interior space 26 ... Speaker 39, 39A ... Gain adjuster 40 ... Frequency determiner 42 ... Rotational frequency detector

Claims (4)

A rotation frequency detector for detecting a rotation frequency of a rotating body related to operation of an engine mounted on the vehicle;
A first reference signal generator that generates a first reference signal related to the rotating body based on the rotation frequency;
A rotating body vibration noise control device that outputs a first canceling signal for canceling vibration noise of the rotating body based on the first reference signal;
A second reference signal generator for generating a second reference signal for road noise;
A road noise control device that outputs a second cancellation signal for canceling the road noise based on the second reference signal;
An active vibration noise control system for a vehicle comprising:
The road noise control device is:
A gain adjuster for adjusting a gain for amplifying the second canceling signal; An active vibration noise control system for vehicles, which is lowered when the frequency is reached. The active vibration noise control system for a vehicle according to claim 1 ,
The vehicular active vibration noise control system, wherein the gain of the gain adjuster is lowered so that the volume increase in the frequency within the sound increase frequency region is less than or equal to a predetermined volume increase. A road noise control device that includes a reference signal generator that generates a reference signal related to road noise, and that outputs a cancellation signal for canceling the road noise based on the reference signal;
A rotation frequency detector for detecting a rotation frequency of a rotating body related to operation of an engine mounted on the vehicle;
An active vibration noise control system for a vehicle comprising:
The road noise control device is:
A gain adjuster for adjusting a gain for amplifying the canceling signal, and the gain of the gain adjuster is set to a frequency within a sound increase frequency region in which the rotation frequency is increased by the output of the canceling signal . An active vibration noise control system for vehicles characterized by being lowered occasionally. The active vibration noise control system for a vehicle according to claim 3 ,
The vehicular active vibration noise control system, wherein the gain of the gain adjuster is lowered so that the volume increase in the frequency within the sound increase frequency region is less than or equal to a predetermined volume increase.

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