Active vibration and noise control device

Abstract

Even when the periodic noise component is small, it is possible to accurately determine the mixing of disturbances and stably reduce the noise. 【Solution means】The noise control device 100 includes speakers 12a - 12d that output cancellation sound for canceling the noise, error microphones 13a - 13d that generate an error signal e from the noise and the cancellation sound, and a control filter that generates the cancellation sound y from a reference signal r corresponding to the noise. Further, the noise control device 100 includes a disturbance determination unit that determines the presence or absence of a disturbance using the error signal e. Then, the disturbance determination unit calculates the overall correlation by adding the correlation functions of each of the plurality of input reference signals r and the error signal e, and determines the presence or absence of a disturbance based on the overall correlation.

Description

Technical Field

[0001] The present invention relates to an active vibration and noise control device.

Background Art

[0002] A conventional active vibration and noise control device includes an anti-noise output device that outputs anti-noise for canceling noise, a noise signal generation device that generates a noise signal based on the noise, and a control device that controls the anti-noise output device based on the noise signal. The control device acquires buffer data in which the noise signal is accumulated in time series, generates a plurality of divided data by dividing the buffer data, and calculates a correlation value of the buffer data based on the plurality of divided data. Then, it detects the presence or absence of disturbance mixed into the buffer data based on the correlation value, and switches the control of the anti-noise output device according to the presence or absence of disturbance mixed into the buffer data (see, for example, Patent Document).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there are cases where the periodic noise component is small (for example, when there is no engine noise in the electric driving mode of an electric vehicle or a hybrid vehicle). In such cases, road noise and aerodynamic noise are dominant, and the indoor noise becomes a highly random noise, so the autocorrelation is inevitably small. Therefore, even if an attempt is made to determine the mixing of disturbance as in a conventional active vibration and noise control device by a decrease in the correlation value, it cannot be accurately determined. Therefore, in the conventional art, it has been difficult to control the on / off or increase / decrease of the noise cancellation that reduces indoor noise depending on the presence or absence of disturbance. In addition, there is a risk of amplifying the noise, and the noise reduction effect is not stable. For this reason, further improvement has been demanded. An object of the present invention is to provide an active vibration noise control device that can accurately determine the intrusion of disturbance and stably reduce noise even when the periodic noise component is small.

Means for Solving the Problems

[0005] To solve the above problems, the active vibration noise control device of the present invention includes a speaker that outputs noise cancellation for canceling noise, and an error microphone that generates an error signal from the noise and the noise cancellation. The active vibration noise control device includes a control filter that generates noise cancellation from a reference signal corresponding to the noise, and a disturbance determination unit that determines the presence or absence of disturbance using the error signal. The disturbance determination unit calculates the overall correlation by adding the correlation functions of each of the plurality of input reference signals and the error signal, and determines the presence or absence of disturbance based on the overall correlation.

Effects of the Invention

[0006] According to the present invention, there is provided an active vibration noise control device that can accurately determine the intrusion of disturbance and stably reduce noise even when the periodic noise component is small.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0008] The following describes embodiments of the present invention with appropriate reference to the drawings. The same reference numerals are assigned to the same components, and redundant descriptions are omitted. In this specification, the "^" (hat) appended to various reference numerals indicates an identified value or an estimated value. "^" is attached above various reference numerals in the drawings, but is attached after various reference numerals in the text. [First Embodiment] FIG. 1 shows a vehicle 1 to which an active vibration and noise control device (hereinafter, also abbreviated as "noise control device" or "ANC-ECU") 100 according to the first embodiment is applied. In the description of the vehicle 1, the same elements are assigned the same numbers, and redundant descriptions are omitted. Also, when explaining the directions, it is explained based on the front, rear, left, right, up, and down (xyz) as viewed from the driver of the vehicle 1. Note that the vehicle width direction and the left-right direction are synonymous.

[0009] The noise control device 100 is an ANC device (Active Noise Control Device) for reducing the noise d generated in the passenger compartment 2 of the vehicle 1. More specifically, the noise control device 100 generates a canceling sound y having a phase opposite to that of the noise d, and causes the generated canceling sound y to interfere with the noise d. Thereby, the noise control device 100 can reduce the noise d to be reduced.

[0010] For example, the noise d to be reduced by the noise control device 100 is road noise caused by the vibration of the wheels due to the force from the road surface. Note that the noise d to be reduced by the noise control device 100 may be noise other than road noise (for example, drive system noise or wind noise caused by the vibration of a drive source such as an internal combustion engine or an electric motor).

[0011] The noise control device 100 according to the first embodiment shown in FIG. 1 includes a plurality of speakers 12a - 12d that output a canceling sound y for canceling the noise d. Further, the noise control device 100 includes a plurality of error microphones 13a - 13d that generate an error signal e from the noise d and the canceling sound y.

[0012] Also, the noise control device 100 according to the first embodiment includes a plurality of acceleration sensors 14a to 14d. In the first embodiment, a total of four acceleration sensors 14a to 14d are provided, one for each of the four wheels on the front, rear, left, and right of the vehicle 1. Each of the acceleration sensors 14a to 14d is configured to detect accelerations in three axial directions in the front - rear, left - right, and up - down (xyz) directions, and generate vibrations transmitted to the vehicle body due to the contact between the road surface, which is the source of road noise, and the wheels as reference signals r1 to rN. The reference signals r1 to rN obtained by each of the acceleration sensors 14a to 14d mainly represent the vibrations in the xyz directions applied from each wheel to the vehicle body. And the reference signals r1 to rN do not include components of disturbance factors such as the sound of the air conditioner wind provided in the vehicle 1 or the sound of the wind entering the passenger compartment 2 when the window is opened.

[0013] As shown in FIG. 2, the noise control device 100 includes a control filter section 10 that generates a canceling sound from the reference signal, a disturbance determination section 130, and a control operation setting section 140. The reference signals r1 to rN generated by each of the acceleration sensors 14a to 14d are respectively sent to the control filter section 10 and the disturbance determination section 130. The control filter unit 10 of the first embodiment has, for example, as shown in FIG. 3, N (N = 12) control filters 10a to 10n for each channel of each of the acceleration sensors 14a to 14d.

[0014] Here, one control filter 10a constituting the control filter unit 10 of the present invention will be described. In addition, the description of each of the other control filters 10b to 10n is omitted because it is the same as that of the control filter 10a. As shown in FIG. 3, the control filter 10a has a noise control unit 110 and a sound field learning unit 120. The noise control unit 110 and the sound field learning unit 120 are configured by, for example, a computer having a processor (such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit)) and a storage device (such as a ROM (Read Only Memory) or a RAM (Random Access Memory)). In addition, the noise control device 100 may configure the configurations of the noise control unit 110, the sound field learning unit 120, and the disturbance determination unit 130 or the control operation setting unit 140 described later, other than the speakers 12a to 12d, the error microphones 13a to 13d, and the acceleration sensors 14a to 14d, as, for example, one piece of hardware, or may be configured as a unit composed of a plurality of pieces of hardware.

[0015] The noise control unit 110 mainly includes a first filter 111, a secondary path filter unit 112, and a control update unit 113. Reference signals r1 to rN corresponding to the noise d sent from the acceleration sensors 14a to 14d are input to the noise control unit 110. The reference signals r1 to r12 generated by the acceleration sensors 14a to 14d of the first embodiment mainly include vibration components applied to the vehicle body from the four wheels respectively. And the reference signals r1 to r12 hardly contain components that are disturbance factors such as the sound of the air conditioner and the sound of the wind that enters the passenger compartment 2 when the window is opened.

[0016] The first filter 111 of the first embodiment generates control signals u1 to uN from these reference signals r1 to rN. The first filter 111 of the first embodiment corresponds to, for example, an FIR (Finite Impulse Response) filter (finite impulse response filter). The FIR filter is a type of digital filter and is a filter with a finite impulse response duration. In other words, the FIR filter is a filter whose output signal (impulse response) converges within a finite time when an impulse signal is input. The first filter 111 sends the control signals u1 to uN to each speaker 12a - 12d. Each speaker 12a - 12d outputs the cancellation sound y using the control signals u1 to uN.

[0017] Also, the secondary path filter section 112 is composed of a secondary path filter having filter characteristics C^. The secondary path filter is a filter corresponding to an estimated value of the transfer characteristic C of the cancellation sound y from the speakers 12a - 12d to the error microphones 13a - 13d. For the secondary path filter, an FIR filter may be used, or a SAN (Single Frequency Adaptive Notch) filter, which is a single - tap adaptive filter specialized for periodic noise, may be used.

[0018] Furthermore, the control update section 113 adaptively updates the filter characteristics W of the first filter 111 using an adaptive algorithm such as the LMS (Least Mean Square Algorithm). The control update section 113 receives the reference signals r1 to rN from the acceleration sensors 14a - 14d passed through the secondary path filter section 112 as the reference signal r and the error signals e1 to eN generated by the error microphones 13a - 13d. Then, the control update section 113 adaptively updates the filter characteristics W1 to WN of the first filter 111 so that the reference signal r becomes minimum according to the error signal e.

[0019] As a result, the first filters 111 of the respective noise control units 110 filter the respective reference signals r1 to rN with the adaptively updated filter characteristics W1 to WN. Then, each first filter 111 generates a control signal u for controlling the outputs of the speakers 12a - 12d. Also, the reference signals r1 to rN sent from the acceleration sensors 14a - 14d are input to the sound field learning unit 120 of the noise control device 100. Each sound field learning unit 120 includes a primary path filter unit 121 having filter characteristics Ĥ provided for each channel, and a primary path update unit 122. Then, the reference signals r1 to rN are input to the primary path filter unit 121 and the primary path update unit 122 of each sound field learning unit 120, respectively.

[0020] Also, the sound field learning unit 120 includes a secondary path filter unit 123 having filter characteristics Ĉ, and a secondary path update unit 124. Then, the control signals u1 to uN generated by the first filter 111 are input to the secondary path filter unit 123 and the secondary path update unit 124 of each sound field learning unit 120.

[0021] Also, a first polarity inversion unit 125, a second polarity inversion unit 126, and an adder 127 are provided in these sound field learning units 120. The first polarity inversion unit 125 inverts the polarities of the noise signals d̂1 to d̂N generated by the primary path filter unit 121 and sends them to the adder 127.

[0022] Furthermore, the second polarity inversion unit 126 inverts the polarities of the cancellation sound signals ŷ1 to ŷN generated by the secondary path filter unit 123 and sends them to the adder 127. The adder 127 adds the noise signal d̂ with the inverted polarity, the cancellation sound signal ŷ with the inverted polarity, and the error signal e generated by the error microphones 13a - 13d to obtain error signals e1 to eN, respectively. Each of the error signals e1 to eN is sent to the corresponding primary path update unit 122 and secondary path update unit 124 and is used for adaptively updating the primary path filter unit 121 and the secondary path filter unit 123.

[0023] Further, the disturbance determination unit 130 receives the reference signals r1 to rN sent from the acceleration sensors 14a to 14d and the error signal e sent from each of the error microphones 13a to 13d. For example, in the first embodiment, as shown in FIG. 4, corresponding to each of the plurality of error microphones 13a, 13b..., noise control devices 100a, 100b... having the same configuration as the noise control device 100 shown in FIG. 3 are provided. Each of the noise control devices 100a, 100b is connected to each of the acceleration sensors 14a to 14d, the disturbance determination unit 130, and the control operation setting unit 140. Further, the noise control devices 100a, 100b are respectively connected to the corresponding speakers 12a or 12b. In FIG. 4, the description of the error microphones 13c, 13d and the noise control devices corresponding to the error microphones 13c, 13d is omitted. These noise control devices are also connected to each of the acceleration sensors 14a to 14d, the disturbance determination unit 130, the control operation setting unit 140, and the speakers 12c to 12d in the same manner as the noise control devices 100a, 100b (see FIG. 1).

[0024] For example, in an electric vehicle or a hybrid vehicle, the noise in the passenger compartment 2 is mainly dominated by random noise such as road noise or aerodynamic noise. On the other hand, the noise of the air conditioner wind provided in the vehicle 1 and the noise of the wind entering the passenger compartment 2 when the window is opened also have strong randomness. Even in such a case, the disturbance determination unit 130 needs to separate the disturbance noise from the noise in the passenger compartment 2 and determine the presence or absence of the disturbance.

[0025] Therefore, the disturbance determination unit 130 obtains the correlation functions (Vc1 to VcN) between each of the plurality of input reference signals r1 to rN and the error signal e. Further, the disturbance determination unit 130 adds up the obtained correlation functions (Vc1 to VcN) to calculate the overall correlation (Vcall: also referred to as the correlation value). Then, the disturbance determination unit 130 is configured to determine the presence or absence of the disturbance based on the overall correlation. 4, when there are noise control devices 100a, 100b... corresponding to a plurality of error microphones 13a, 13b..., the presence or absence of disturbance may be determined for the error microphone signal of each of the noise control devices 100a, 100b.... Therefore, it is possible to identify the noise control device (error microphone) containing disturbance and appropriately stop the output of the noise control device.

[0026] Further, the disturbance determination unit 130 determines the presence or absence of disturbance based on the overall correlation from the error signals e generated by each of the error microphones 13a, 13b.... At this time, the correlation values ​​of at least any pair of the reference signals r1 to rN can also be used as a common correlation value. In this way, when determining whether or not a disturbance is present using the error signals e generated by each of the error microphones 13a, 13b..., the amount of calculation can be reduced by calculating the correlation of the reference signals using a common value.

[0027] The cross-correlation function is calculated using the convolution operation of two signals as follows: First, we will explain the calculation method (A), which is one of the calculation methods performed by the disturbance determination unit 130. In the calculation method (A), the disturbance determination unit 130 calculates a cross-correlation function (Vci(t)) between each of the reference signals r1, r2, ..., rN and the error signal e by using the following formula (1). [Formula 1] JPEG0007698762000002.jpg12123 Here, t is discrete time, n is the current time, and N is the size of the signal buffer. τ is the time difference. The time difference γ is set in advance as a control parameter taking into consideration the propagation time of the noise d into the vehicle interior 2.

[0028] Next, the disturbance determination unit 130 adds up the absolute values ​​of the correlation functions (Vc1, Vc2 to VcN) between each of the reference signals r1 to rN obtained by equation (1) and the error signal e, as shown in the following equation (2), to calculate the overall correlation value Vcall(t). [Formula 2] JPEG0007698762000003.jpg16123 As a result, the disturbance determination unit 130 obtains the overall correlation value Vcall used for determining the presence or absence of disturbance.

[0029] Next, the calculation method (B) performed by the disturbance determination unit 130 will be described here. In the calculation method (A), when there is a correlation between the reference signals, the overall correlation value Vcall may overestimate the correlation between the reference signal r and the error signal e. Therefore, the disturbance determination unit 130 obtains the correlation value VcriJ of at least one pair of the plurality of input reference signals r1 to rN. Then, the disturbance determination unit 130 performs an operation to remove the correlation value Vcrij of the reference signal obtained from the overall correlation. Thereby, the overall correlation value is obtained so as not to become too large. In the calculation method (B), using Equation (3), a calculation is performed to remove at least the sum value of the correlation values Vcrij(τ) of the reference signals from the overall correlation value Vcall(t) obtained in Equation (2). [Equation 3] JPEG0007698762000004.jpg15123 Here, in order to set the same time difference τ for the two signals, τ = 0 can be set. For example, when exactly the same vibration input is transmitted from the four wheels of the vehicle 1 to the vehicle body, it is conceivable that noise d is generated in the passenger compartment 2 due to the vibration. For example, when vibrations are applied to the left and right wheels in the same vertical (z) direction, the correlation between the reference signals r1, r2 or r3, r4 of the paired acceleration sensors 14a, 14b or 14c, 14d and the noise d in the passenger compartment 2 becomes 1 (when the cross-correlation is normalized). At this time, the correlation between the paired reference signals r, for example, between the acceleration sensors 14a, 14b or 14c, 14d of the left and right wheels that form a pair also becomes 1. Therefore, the disturbance determination unit 130 calculates the correlation value Vc(τ) as shown in the following Equation (4). [Equation 4] JPEG0007698762000005.jpg10119 Therefore, as expected, it can be seen that the reference signal r and the error signal e are perfectly correlated signals. Therefore, even if the correlation value Vcall used for judgment is calculated by removing the correlation value Vcrij(t) of the reference signal from the overall correlation value Vcall(t), it does not differ significantly and an effective judgment of disturbance can be made.

[0030] Next, calculation method (C) will be described. Calculation method (C) can reduce the amount of calculation compared to calculation method (B). In the calculation method (C), the disturbance determination unit 130 calculates a cross-correlation function Vci(t) between each of the reference signals r1, r2, . . . rN and the error signal e by using the following equation (5). [Formula 5] JPEG0007698762000006.jpg12119 Here, the channel number of the reference signal for calculating the correlation is specified as a control parameter in the disturbance determination unit 130. For example, at least one channel number of the reference signals r1, r2, ..., rN having a high correlation with the error signal e indicating the indoor sound may be set in advance.

[0031] Next, the disturbance determination unit 130 adds up the results obtained by equation (5) as shown in the following equation (6) to calculate a correlation value Vcall(τ) that numerically indicates the overall correlation. [Formula 6] JPEG0007698762000007.jpg13119 As a result, in calculation method (C), it is possible to omit the calculation of subtracting the correlation between the reference signals from the overall correlation value obtained by adding up the results. Even in this case, the tendency for the correlation value to become smaller due to the inclusion of disturbances remains unchanged. Therefore, the disturbance determination unit 130 can make an effective determination using the overall correlation value Vcalc calculated by equation (6).

[0032] The control operation setting section 140 receives the presence or absence of a disturbance determined by the disturbance determining section 130 . The disturbance determination unit 130 uses the presence or absence of disturbance to set the operation of each of the control filters 10a to 10n. As shown in FIG. 4, in the noise control device 100 of the first embodiment, a plurality of error microphones 13a - 13d are respectively and dispersedly arranged on the headrests (see FIG. 2) that are paired left and right in the front and rear seats in the vehicle compartment 2. The disturbance determination unit 130 calculates the correlation for the error signals e sent from the respective error microphones 13a - 13d using calculation methods (A) to (C). The disturbance determination unit 130 calculates the overall correlation value by adding the correlation functions of each of the plurality of input reference signals rN and the error signal e. Then, the disturbance determination unit 130 determines the presence or absence of disturbance based on the obtained overall correlation value.

[0033] Note that when the disturbance determination unit 130 calculates the overall correlation by adding the correlation functions of each of the plurality of input reference signals r1, etc. and the error signal e, when the reference signal r1, etc. and the error signal e have the same sign, the correlation function can be set to -1. Thereby, when the disturbance determination unit 130 calculates the overall correlation value Vcall by adding the correlation functions of each of the plurality of input reference signals r1 to rn and the error signal e, the calculation becomes simple. Therefore, when performing such a calculation, the disturbance determination unit 130 can obtain the overall correlation value Vcall with a small amount of calculation.

[0034] The noise control device 100 of the first embodiment configured in this way can accurately determine the intrusion of disturbance even when the periodic noise component is small, and can further prevent noise amplification due to the divergence of control caused by the disturbance, and can reduce noise more stably. Specifically, a plurality of reference signals r1 to rN are input to the respective noise control units 110. When a component indicating disturbance is included in any of the reference signals r1 to rN, the correlation values (Vc1 to VcN) of the correlation functions of these reference signals r1 to rN and the corresponding error signals e1 to eN respectively decrease. Then, the overall correlation value Vcall is calculated by adding the obtained correlation functions. At this time, the overall correlation value Vcall obtained by adding a plurality of them decreases significantly when the intrusion of disturbance has occurred.

[0035] The first filter 111 can generate a control signal u for controlling the outputs of the speakers 12a - 12d based on such an overall correlation value Vcall by filter characteristics W1 to WN that are adaptively updated. Therefore, when the first filter 111 outputs the generated control signal u to the speakers 12a - 12d, each speaker 12a - 12d can generate a cancellation sound y according to the control signal u, and effectively reduce the noise d in the passenger compartment 2.

[0036] In the noise control device 100 of the first embodiment, a reference signal r1 to rN sent from the acceleration sensors 14a - 14d and an error signal e sent from each error microphone 13a - 13d are input to the disturbance determination unit 130. The disturbance determination unit 130 obtains correlation values (Vc1 to VcN) by a correlation function between each of the plurality of input reference signals r1 to rN and the error signal e. Further, the disturbance determination unit 130 calculates an overall correlation value Vcall by adding up the obtained correlation values (Vc1 to VcN). Then, the disturbance determination unit 130 determines the presence or absence of disturbance based on the overall correlation value Vcall.

[0037] In the flowchart of disturbance determination shown in FIG. 5, when the value Vc(t) based on the overall correlation obtained by the disturbance determination unit 130 in step S10 is smaller than a preset first threshold Lt1 and the difference Vc(t) - Vc(t - △) of the value based on the overall correlation is larger than a preset second threshold Lt2 (Yes in step S10), the process proceeds to step S11, and it is determined that there is disturbance mixing. Here, Lt1 is a preset first threshold for the cross - correlation value. Also, Lt2 is a preset second threshold indicating the pace of increase or decrease of the cross - correlation value. Further, t represents discrete time, and △ represents a time interval. Note that the second threshold Lt2 may be a threshold indicating the pace of decrease of the cross - correlation value.

[0038] Then, when the value Vc(t) based on the overall correlation value is not less than a preset first threshold Lt1, or the difference Vc(t) - Vc(t - Δ) of the value based on the overall correlation is not greater than a preset second threshold Lt2 (No in step S10), if at least one of them is satisfied, the process proceeds to step S12 and it is determined that no disturbance has been mixed in.

[0039] Thus, in the flowchart of disturbance determination shown in FIG. 5, not only when the overall correlation value is less than the first threshold Lt1, but also when the overall correlation value increases or decreases at a pace of not less than the second threshold Lt2, or when it decreases at a pace of not less than the second threshold Lt2, it is determined that a disturbance has been mixed in. Thereby, even in the case of an electric vehicle, a hybrid vehicle, etc., where the reference periodic noise component is small and the amount of decrease in correlation is originally small, by using the rapid change in correlation for determination, it is possible to more accurately determine the presence or absence of disturbance mixing. Further, the noise control device 100 of the first embodiment uses the reference signals r1 to rN generated by the acceleration sensors 14a to 14d. Since the reference signals r1 to rN are signals of vehicle body vibration, they do not include components that are disturbance factors such as the sound of the air conditioner's wind or the sound of wind entering the passenger compartment 2 when the window is opened. Therefore, the disturbance determination unit 130 can accurately determine the presence or absence of disturbance mixing in the microphone signal by utilizing the correlation between the reference signals r1 to rN in which wind disturbance is less likely to be mixed and the microphone signal in which wind disturbance is likely to be mixed.

[0040] Then, the determination result of whether or not a disturbance has been mixed in in these steps S11 and S12 can be used for the determination of whether or not a disturbance has been mixed in in step S40 together with or independently of the microphone signal which is the reference signal rN in the flowchart showing the filter control of the second embodiment shown in FIG. 9.

[0041] The following FIGS. 6 to 8 are examples for determining the presence or absence of disturbance in the first embodiment. However, the results of determining the presence or absence of these disturbances may be used for controlling the control filters 10a to 10n of the second embodiment shown in FIG. 9. In the flowchart of disturbance determination shown in FIG. 6, in addition to the conditions of the flowchart shown in FIG. 5, the air volume of the air conditioner is further used for determining the mixing (presence or absence) of disturbance. The first filter 111 determines that a disturbance has occurred when the value Vc(t) based on the overall correlation is smaller than a preset first threshold Lt1' and the value of the air volume of the air conditioner obtained from the air conditioner blower voltage is larger than a preset third threshold Lt3.

[0042] That is, in step S20, when the correlation value Vc(t) based on the overall correlation by the disturbance determination unit 130 is smaller than a preset first threshold Lt1 and the difference Vc(t) - Vc(t - △) of the correlation value based on the overall correlation is larger than a preset second threshold Lt2, and in addition, when the air conditioner blower voltage is larger than a preset third threshold Lt3 and the air conditioner is operating (Yes in step S20), it proceeds to step S21 and determines that there is disturbance mixing.

[0043] Also, even when the correlation value Vc(t) based on the overall correlation by the disturbance determination unit 130 is smaller than a preset first threshold Lt1 and the difference Vc(t) - Vc(t - △) of the correlation value based on the overall correlation is larger than a preset second threshold Lt2, if the air conditioner blower voltage is not larger than a preset third threshold Lt3, it is determined that the air conditioner is not operating (No in step S20), and it proceeds to step S22 and determines that there is no disturbance mixing. The determination results of whether or not disturbance is mixed in steps S21 and S22 can be used for determining whether or not disturbance is mixed in step S40 together with the microphone signal which is the reference signal rN or alone in the flowchart showing the filter control of the second embodiment shown in FIG. 9.

[0044] Furthermore, in the flowchart of disturbance determination shown in FIG. 7, in addition to the conditions of the flowchart shown in FIG. 5, the opening / closing state of the window is further used to determine the presence or absence of disturbance. The disturbance determination unit 130 uses a window control signal for controlling the opening and closing of the window to determine disturbance. When the value based on the overall correlation is equal to or less than a preset first threshold Lt1' and the window control signal detects that the opening / closing state of the window is open, it determines that there is disturbance.

[0045] That is, in step S30, in addition to the case where the correlation value Vc(t) based on the overall correlation by the disturbance determination unit 130 is less than a preset first threshold Lt1 and the difference Vc(t) - Vc(t - Δ) of the correlation values based on the overall correlation exceeds a preset second threshold Lt2, when the opening / closing state of the window is "open" (Yes in step S30), it proceeds to step S31 and determines that there is disturbance mixing.

[0046] Also, even when the correlation value Vc(t) based on the overall correlation by the disturbance determination unit 130 is less than a preset first threshold Lt1 and the difference Vc(t) - Vc(t - Δ) of the correlation values based on the overall correlation exceeds a preset second threshold Lt2, if the opening / closing state of the window is not "open" but "closed" (No in step S30), it proceeds to step S32 and determines that there is no disturbance mixing. And the determination result of whether or not disturbance is mixed in these steps S31 and S32 can be used, together with the microphone signal which is the reference signal rN, or alone, to determine whether or not disturbance is mixed in step S40 in the flowchart showing the filter control of the second embodiment shown in FIG. 9. In this way, after obtaining the overall correlation value Vcall, the disturbance determination unit 130 can more accurately determine the presence or absence of disturbance by adding conditions where disturbance mixing is certain. And the control operation setting unit 140 of the first embodiment switches the operations of the control filters 10a to 10n based on the accurate presence or absence of disturbance by the disturbance determination unit 130, and the first filter 111 can stably reduce noise.

[0047] [Second Embodiment] FIG. 8 shows an active vibration noise control device (noise control device) 200 according to the second embodiment. Note that the same or equivalent parts as those in the first embodiment are denoted by the same reference numerals and will not be described again. The noise control device 200 has a reference microphone 13e added to the configuration of the noise control device 100 of the first embodiment. The reference microphone 13e is provided in the same passenger compartment 2 as the error microphones 13a - 13d. The reference microphone 13e is connected to each of the control filters 10a - 10n of the disturbance determination unit 130 and the control filter unit 10, respectively. Further, the reference microphone 13e sends a reference signal rN generated from the noise in the passenger compartment 2 to the disturbance determination unit 130 and each of the control filters 10a - 10n. A single reference signal rN, which is the reference signal N of the reference microphone 13e together with the reference signals r1 to rN sent from the acceleration sensors 14a - 14d, is input to the control filters 10a - 10n. Thereby, the control filters 10a - 10n generate a canceling sound y. The control operation setting unit 240 of the second embodiment is configured to instruct the control update unit 113 whether to apply and update the filter characteristics W, Ĉ, Ĥ or to stop the application and update according to the presence or absence of the disturbance determined by the disturbance determination unit 130.

[0048] FIG. 9 is a flowchart showing an example of an operation of reflecting the determination result of the presence or absence of disturbance in the control of the control filter unit 10 for noise control. First, in step S40, a correlation value is calculated by a microphone signal which is the reference signal rN or a reference signal r from the acceleration sensor 14a or the like. Next, in step S41, it is determined by the disturbance determination unit 130 whether or not disturbance is mixed in. If there is disturbance (Yes in step S41), the process proceeds to step S42. If there is no disturbance (No in step S41), the process proceeds to step S45, where the filter characteristics W, Ĉ, Ĥ are updated and an output of adaptive update by the control update unit 113 is performed.

[0049] In step S45, when no disturbance is mixed into any microphone, the filter characteristics W, MC^, and H^ are updated normally, and a control output is generated using the updated values. As a result, both the adaptive update and the control output of control ch are performed only using the reference signal in a state without disturbance components. Specifically, when no disturbance is mixed into any microphone, the control operation setting unit 240 causes the control update unit 113 to update the filter characteristics W, C^, and H^ normally and generates a control output using the updated values. In this way, when the adaptive update and the output of control ch are performed, a cancellation sound y without disturbance components can be generated, and the noise d in the passenger compartment 2 can be effectively reduced.

[0050] Also, even when there is a disturbance, it is determined in step S42 whether to use it as a reference signal. Specifically, the flag indicating whether to use the reference signal of the reference microphone 13e is a control parameter set in advance. When not using it as a reference signal (No in step S42), the process proceeds to step S44. When using it as a reference signal (Yes in step S42), the process proceeds to the next step S43 to stop the update of the filter characteristics W, C^, and H^ and stop the corresponding control ch output.

[0051] First, in step S44, when a disturbance is mixed into one or more microphones, if the microphone with the corresponding disturbance is used only as an error signal for filter update, the adaptive update of the filter cannot be performed correctly. Therefore, the learning of the filter characteristics W, C^, and H^ is stopped. On the other hand, since there is no disturbance in the reference signals r1~rN for generating the control output, the filter values immediately before the disturbance determination may be switched to a fixed filter to continue the output of the cancellation sound.

[0052] Specifically, the control operation setting unit 240 stops the update of the filter characteristics W, C^, and H^ and continues the output using a fixed filter (or the control filter unit 10 having the previous filter characteristics W^). Therefore, in step S44, when noise is mixed into one or more microphones, if the microphone with the corresponding noise is only used as the error signal for filter update, even if the adaptive update of the filter is stopped, the output generation can be continued using the values of the filter characteristics W, Ĉ, and Ĥ immediately before the noise determination as a fixed filter.

[0053] In step S43, when there is noise in the reference microphone, both the application update and the control output cannot be correctly controlled. Therefore, both the application update and the control output are stopped. Specifically, if the detected value of the reference microphone 13e contains noise, both the control output of control ch and the output of the adaptive update by the control update unit 113 are stopped. As a result, in a state where the application update and the control ch output cannot be accurately performed due to noise, neither the application update nor the control output of control ch is performed, and inaccurate application updates and control ch outputs containing noise components can be avoided.

[0054] In the noise control device 200 of the second embodiment configured as described above, when noise occurs, the learning of the filter characteristics W, Ĉ, and Ĥ is stopped. On the other hand, since the reference signals r1 to rN sent from the acceleration sensors 14a to 14d are vibration signals of the vehicle body, noise is less likely to be mixed in and the influence of noise is small. Also, the output of the canceling sound can be continued by the filtering process with the reference signal without noise being mixed in. As a result, it is possible to prevent the volume of the canceling sound y from increasing or decreasing suddenly due to extreme control changes. Therefore, the noise control device 200 of the second embodiment can reduce noise more stably and improve the control quality of the noise.

[0055] Regarding other configurations and operational effects, since they are the same as those of the first embodiment, the description is omitted.

[0056] As described above, the active vibration and noise control device of the present invention includes speakers 12a - 12d that output a cancellation sound y for canceling noise, and error microphones 13a - 13d that generate an error signal e from the noise d and the cancellation sound y. Further, the active vibration and noise control device includes a first filter 111 that generates the cancellation sound y from a reference signal r corresponding to the noise d, and a disturbance determination unit 130 that determines the presence or absence of a disturbance using the error signal e. The disturbance determination unit 130 calculates the total correlation value Vcall by adding the correlation functions (Vc1 to VcN) between each of the plurality of input reference signals r1 to rN and the error signal e, and determines the presence or absence of a disturbance based on the total correlation value Vcall.

[0057] The active vibration and noise control device configured in this way can accurately determine the intrusion of a disturbance even when the periodic noise component is small, prevent noise amplification due to divergence of control caused by the disturbance, and can more stably reduce noise. Specifically, if each of the plurality of input reference signals r1 to rN contains a component indicating a disturbance, the total correlation value Vcall obtained by adding a plurality of correlation functions (Vc1 to VcN) between each of the reference signals r1 to rN and the error signal e will significantly decrease. Therefore, the disturbance determination unit 130 can accurately determine the presence or absence of a disturbance by obtaining the total correlation value Vcall.

[0058] Also, for example, a plurality of acceleration sensors 14a to 14d that detect the acceleration in the three axes of the x, y, and z directions, like the noise control device 100 of the first embodiment, can be used to obtain reference signals r1 to rN corresponding to the noise d respectively. The reference signals r1 to rN generated by the acceleration sensors 14a to 14d do not contain components of disturbance factors. Therefore, the presence or absence of a disturbance can be determined more accurately. Further, the noise control device 100 of the first embodiment is provided with a total of four acceleration sensors 14a - 14d, one for each wheel in the front, rear, left, and right directions. As a result, a total of 12ch (channels) of reference signals r1 to rN (N = 12) are generated in total, and the determination accuracy of the presence or absence of a disturbance can be further improved.

[0059] Furthermore, the disturbance determination unit 130 obtains the correlation value Vcrij of at least a pair of reference signals among the plurality of input reference signals r1 to rN, and removes the correlation (correlation value Vcrij) of the reference signals r1... etc. obtained from the overall correlation value Vcall. That is, when there is a correlation between the paired reference signals r1, r2, etc., the overall correlation coefficient (correlation value Vcrij) obtained by adding the correlation functions (Vc1 to VcN) between the reference signals r1 to rN and the error signal becomes large. Therefore, by removing the influence of the correlation of the paired reference signals r1, r2, etc., it is possible to prevent the overall correlation from being overestimated.

[0060] For example, in the vehicle 1 of the first embodiment, when vibrations are applied to the left and right wheels in the up and down (z) direction, which is the same direction, the correlation between the reference signals r1, r2 or r3, r4 of the acceleration sensors 14a, 14b or 14c, 14d, which are paired, and the noise signal in the passenger compartment 2 becomes 1 (when the cross-correlation is normalized). At this time, the correlation between the paired reference signals r, for example, between the acceleration sensors 14a, 14b or 14c, 14d of the left and right paired wheels also becomes 1. Therefore, by removing the influence of the correlation of the paired reference signals r1, r2, etc., the evaluation of the overall correlation value Vcall can be further stabilized.

[0061] Also, a plurality of error microphones 13a - 13d are provided, and the disturbance determination unit 130 determines the presence or absence of disturbance based on the overall correlation from the error signals e generated by the respective error microphones 13a - 13d. The disturbance determination unit 130 uses a pair of correlation values Vcrij among the reference signals r1 to rN as a common correlation value during the determination of each error microphone 13a - 13d. Thereby, when the disturbance determination unit 130 performs disturbance determination using the error signals e generated by the respective error microphones 13a - 13d, the amount of calculation can be reduced by calculating the correlation of the reference signals r1 to rN using a common value.

[0062] Then, when the value based on the overall correlation is smaller than a preset first threshold value Lt1 and the difference in the value based on the overall correlation is larger than a preset second threshold value Lt2, the disturbance determination unit 130 determines that there is a disturbance. Accordingly, when not only is the correlation smaller than the first threshold value Lt1, but also the correlation increases and decreases at a pace greater than a certain level (the second threshold value Lt2), it is determined that a disturbance has been mixed in. Accordingly, even when the periodic noise component is small and the decrease amount of the reference correlation is small, by using the rapid change in the correlation for determination, it is possible to more accurately determine the disturbance.

[0063] Also, the disturbance determination unit 130 uses the air conditioner blower voltage that controls the air volume of the air conditioner for disturbance determination. The first filter 111 determines that a disturbance has occurred when the value based on the overall correlation is smaller than a preset first threshold value Lt1 and the value of the air volume of the air conditioner obtained from the air conditioner blower voltage is larger than a preset third threshold value Lt3.

[0064] For example, the disturbance determination unit 130 obtains the value of the air conditioner air volume using the air conditioner blower voltage. Therefore, even if the threshold value of the determination condition based on the correlation is set loosely, false detection of a disturbance can be prevented.

[0065] Furthermore, the disturbance determination unit 130 uses the window control signal that controls the opening and closing of the window for disturbance determination, and when the value based on the overall correlation is smaller than a preset first threshold value Lt1 and it is detected by the window control signal that the opening and closing state of the window is open, it determines that there is a disturbance. By using the determination that the window is open in this way, even if the threshold value of the determination condition based on the correlation is set loosely, false detection of a disturbance can be prevented.

[0066] Then, the active vibration noise control device includes a control operation setting unit 140 that sets the operation of the control filter unit 10 according to the presence or absence of a disturbance determined by the disturbance determination unit 130, and a reference microphone 13e provided in the same passenger compartment 2 as the error microphones 13a - 13d. The control filter unit 10 can generate the canceling sound y using the detection value of the reference microphone 13e as a reference signal rN. Furthermore, when the disturbance determination unit 130 determines that there is a disturbance, the control operation setting unit 140 stops generating the canceling sound y using the detection value of the reference microphone 13e. As a result, when there is a disturbance in the space of the vehicle interior 2, the generation of the canceling sound y can be stopped because the detection value of the reference microphone 13e may also include the disturbance. Therefore, it is possible to prevent the unpleasant canceling sound y from being output. Also, for example, if there is a possibility that the detection value of the reference microphone 13e also contains disturbance, the detection value of the reference microphone 13e may not be used as the reference signal rN, but may be used as one of the error signals that are determined to be free of disturbance.

[0067] When the disturbance determination unit 130 determines that there is a disturbance, the control operation setting unit 140 stops learning by the control filter unit 10 and switches to the control filter unit 10 before learning was stopped or to a fixed filter unrelated to learning to continue outputting the cancellation sound, and switches the reference signal from the detection value of the reference microphone to the detection value of the acceleration sensor. In other words, when the reference microphone 13e is not used, the reference signal rN including the reference signals r1 to rN sent from the acceleration sensors 14a to 14d is not affected much by disturbances. Therefore, when a disturbance occurs, the learning of the control filter unit 10 is stopped. Then, the control filter unit 10 before the learning was stopped, a fixed filter unrelated to the learning, or the reference signals r1 to rN sent from the acceleration sensors 14a to 14d is switched to continue outputting the canceling sound. This makes it possible to prevent the volume from being suddenly increased or decreased due to an extreme change in control, thereby maintaining the noise reduction effect with improved noise control quality.

[0068] Furthermore, when the correlation function indicating correlation is such that the reference signal and the error signal have the same sign, it is set to 1 in the embodiment, and when the reference signal and the error signal do not have the same sign, the correlation function is set to -1 in the embodiment. The correlation functions between each of the plurality of input reference signals and the error signal are added together to obtain the overall correlation. By making the calculation of the overall correlation function simple in this way, the amount of calculation can be reduced. Specifically, when the reference signal r and the error signal e have the same sign, the correlation function is set to a predetermined value, for example, 1 in the embodiment. Also, when the reference signal r and the error signal e do not have the same sign, the correlation function has the same absolute value as the predetermined value but the opposite sign, for example, the correlation coefficient is set to -1 in the embodiment. Then, the disturbance determination unit 130 simply obtains the correlation function by adding together the correlation functions between each of the plurality of input reference signals rN and the error signal e. Thereby, it is possible to determine the presence or absence of disturbance with a small amount of calculation together with or instead of the convolution operation. Therefore, compared with the case where the calculation of the overall correlation function is performed only by the convolution operation, the calculation can be made simple, and the amount of calculation can be reduced. Therefore, it is suitable for use in the control of active vibration noise that requires responsiveness, such as the traveling vehicle 1. In this way, the active vibration noise control device of the present invention exhibits practically useful effects such as being able to accurately determine the intrusion of disturbance and stably reduce noise even when the periodic noise component is small.

[0069] The present invention is not limited to the above-described embodiments, and various modifications are possible. The above-described embodiments are exemplified for easy understanding and explanation of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Also, a part of the configuration of each embodiment can be deleted, or addition or replacement with other configurations is possible. Possible modifications to the above embodiments are, for example, as follows.

[0070] For example, in the first embodiment, as shown in FIG. 4, it may be composed only of the noise control devices 100a and 100b, or may be connected only to the speakers 12a and 12b. That is, in the present invention, the quantities of the noise control device 100, the speakers 12a, and the error microphones 13a are not particularly limited.

[0071] And the first filter 111 may determine that there is an external disturbance when the value based on the overall correlation is smaller than a preset first threshold Lt1 and the value of the air volume of the air conditioner is larger than a preset third threshold Lt3. That is, at step S20 of the flowchart shown in FIG. 6, it is not necessary to use whether the difference in the value based on the overall correlation is larger than a preset second threshold Lt2 for determining the presence or absence of an external disturbance. Also, in the flowchart shown in FIG. 7, it is not necessary to use whether the difference in the value based on the overall correlation is larger than a preset second threshold Lt2 at step S30 for determining the presence or absence of an external disturbance.

[0072] Also, although the result of determining the presence or absence of an external disturbance shown in FIGS. 6 to 8 of the first embodiment has been described as being used for the control of the control filter of the second embodiment shown in FIG. 9, it is not particularly limited to this. For example, the result of determining the presence or absence of an external disturbance shown in FIGS. 6 to 8 of the first embodiment may be used for the control of other control filters that do not use the reference microphone 13e.

[0073] Furthermore, in the second embodiment, although the control of the control filter is mainly described as being performed using the determination result of the presence or absence of an external disturbance shown in FIGS. 6 to 8, it is not particularly limited to this. For example, the determination result using a determination method other than the method for determining the presence or absence of an external disturbance in the first embodiment may be used. That is, in the second embodiment, when it is determined by an external disturbance determination unit having another configuration that there is an external disturbance, it is only necessary to stop generating the cancellation sound based on the detection value of the reference microphone 13e.

[0074] Also, the disturbance determination unit that determines the presence or absence of a disturbance using the error signal does not have to use the reference signals r1 to rN corresponding to the noise signals sent from the acceleration sensors 14a to 14d as in the first and second embodiments. For example, various sensors such as a stroke sensor or a pressure sensor that detects the behavior of the suspension may be used, and as long as it is outside the acceleration sensors 14a to 14d and can generate a reference signal corresponding to noise, it may be used. That is, it is sufficient that the disturbance determination unit can determine the presence or absence of a disturbance using the reference signal corresponding to the noise generated by these, and the quantity, shape, and generation method of the reference signal generation are not particularly limited.

Explanation of Signs

[0075] 10 Control filter unit 10a - 10N Control filter 12a - 12d Speaker 13a - 13d Error microphone 130 Disturbance determination unit

Claims

1. A speaker that outputs a canceling sound to cancel out noise; an error microphone for generating an error signal from the noise and the cancellation sound; A control filter that generates the cancellation sound from a reference signal corresponding to the noise; a disturbance determination unit that determines the presence or absence of a disturbance using the error signal, the disturbance determination unit calculates an overall correlation by adding up correlation functions between the error signal and each of the plurality of reference signals that are input; An active vibration noise control device comprising: a control section for controlling a vibration of a vehicle;

2. The disturbance determination unit determines a correlation between at least a pair of the reference signals among the plurality of reference signals inputted, 2. The active vibration noise control system according to claim 1, further comprising: removing the correlation of said reference signal determined from said overall correlation.

3. A plurality of error microphones are provided, the disturbance determination unit determines the presence or absence of a disturbance based on the overall correlation from the error signals generated by the error microphones, 3. The active vibration noise control system according to claim 2, wherein a pair of correlation values ​​of said reference signals are used as a common correlation value when making judgments about each of said error microphones.

4. 2. The active vibration noise control device according to claim 1, wherein the disturbance determination unit determines that a disturbance is present when the value based on the overall correlation is smaller than a predetermined first threshold value and the difference between the values ​​based on the overall correlation is greater than a predetermined second threshold value.

5. The disturbance determination unit uses an air conditioner blower voltage that controls an air volume of an air conditioner to determine whether a disturbance has occurred, 2. The active vibration noise control device according to claim 1, wherein the control filter determines that a disturbance has occurred when the value based on the overall correlation is smaller than a predetermined first threshold value and the value of the air volume of the air conditioner obtained from the air conditioner blower voltage is larger than a predetermined third threshold value.

6. The disturbance determination unit uses a window control signal for controlling opening and closing of a window to determine whether a disturbance has occurred, 2. The active vibration noise control device according to claim 1, wherein when the value based on the overall correlation is smaller than a predetermined first threshold value and when the window control signal detects that the window is open, it is determined that there is a disturbance.

7. a control operation setting unit that sets an operation of the control filter in accordance with the presence or absence of a disturbance determined by the disturbance determination unit; a reference microphone provided in the same vehicle cabin as the error microphone; The control filter is capable of generating the cancellation sound using a detection value of the reference microphone as the reference signal, 2. The active vibration noise control device according to claim 1, wherein the control operation setting unit stops generating the canceling sound based on the detection value of the reference microphone when the disturbance determination unit determines that there is a disturbance.

8. 8. The active vibration noise control device according to claim 7, wherein, when the disturbance determination unit determines that there is a disturbance, the control operation setting unit stops learning by the control filter and switches to the control filter before the learning was stopped or to a fixed filter unrelated to learning to continue outputting the canceling sound, and switches the reference signal from the detection value of a reference microphone to the detection value of an acceleration sensor.

9. A speaker that outputs a canceling sound to cancel out noise; an error microphone for generating an error signal from the noise and the cancellation sound; A control filter that generates the cancellation sound from a reference signal corresponding to the noise; a disturbance determination unit that determines the presence or absence of a disturbance using the error signal, the disturbance determination unit, when calculating an overall correlation by adding up correlation functions between each of the multiple input reference signals and the error signal, sets the correlation function to a predetermined numerical value if the reference signal and the error signal have the same sign, and sets the correlation function to a value with the same absolute value as the predetermined numerical value but with an opposite sign if the reference signal and the error signal do not have the same sign, and determines the presence or absence of a disturbance based on the overall correlation function obtained by adding up the correlation functions between each of the multiple input reference signals and the error signal.

Images