Active noise control device and vehicle

Abstract

An active noise control device and a vehicle. The active noise control device (10) comprises a first adaptive filter (36C) and a first filter coefficient updating unit (40C), wherein the first adaptive filter (36C) generates a control signal (uC) by filtering a reference signal (r) corresponding to noise; and the first filter coefficient updating unit (40C) updates the filter coefficient (W2) of the first adaptive filter according to an addition error signal (eC) and the reference signal (r), wherein the addition error signal (eC) is a signal obtained by adding a first error signal (eL) and a second error signal (eR), wherein the first error signal (eL) is obtained by detecting residual noise by a first microphone (20L), and the second error signal (eR) is obtained by detecting residual noise by a second microphone (20R). Thus, noise can be well reduced and cost reduction can be achieved.

Description

Technical Field

[0001] The present invention relates to an active noise control device and a vehicle. Background Art

[0002] Japanese Patent Publication No. 5-265471 discloses a noise reduction device in a vehicle cabin, which includes a control block, a plurality of speakers, and a plurality of microphones. The control block generates a cancellation signal based on vibrations detected by a plurality of vibration sensors. The plurality of speakers generate cancellation vibrations based on the cancellation signal. The plurality of microphones detect the cancellation error between the cancellation vibration and the vibration from the vibration source. Summary of the invention

[0003] However, the active noise control device disclosed in Japanese Patent Publication No. 5-265471 processes inputs from multiple vibration sensors, outputs based on multiple speakers, and inputs from multiple microphones, so complex control is required. Therefore, the design cost of the active noise control device is increased. In addition, the active noise control device has a large amount of calculation, so an expensive processor is required, resulting in an increase in component costs.

[0004] An object of the present invention is to provide an active noise control device and a vehicle that can effectively reduce noise and achieve cost reduction.

[0005] An active noise control device according to one embodiment of the present invention causes an actuator to output a cancelling sound based on a control signal to reduce noise in a vehicle cabin, the active noise control device comprising a first adaptive filter and a first filter coefficient updating unit, wherein the first adaptive filter generates the control signal by filtering a reference signal corresponding to the noise; the first filter coefficient updating unit updates the filter coefficient of the first adaptive filter according to an addition error signal and the reference signal, the addition error signal being a signal obtained by adding a first error signal and a second error signal, wherein the first error signal is obtained by detecting residual noise generated by interference between the noise and the cancelling sound by a first microphone, the first microphone being arranged on one side of the cabin with a center line of the vehicle in a front-rear direction of the vehicle as the center, and the second error signal is obtained by detecting the residual noise by a second microphone, the second microphone being arranged on the other side of the cabin with the center line of the vehicle as the center.

[0006] A vehicle according to another aspect of the present invention includes the above-mentioned active noise control device.

[0007] According to the present invention, it is possible to provide an active noise control device and a vehicle that can effectively reduce noise and achieve cost reduction.

[0008] The above-mentioned objects, features and advantages will be easily understood from the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a diagram showing an overview of active noise control.

[0010] Figure 2 It is a graph showing the relationship between the frequency of noise and the magnitude of noise.

[0011] Figure 3 It is a top view showing the position where noise is measured.

[0012] Figure 4 It is a block diagram showing a part of a vehicle including an active noise control device according to an embodiment.

[0013] Figure 5 It is a plan view showing an example of a vehicle including an active noise control device according to an embodiment.

[0014] Figure 6 is a graph showing an example of an added error signal.

[0015] Figure 7 This is a flowchart showing an example of the operation of the active noise control device according to the present embodiment. DETAILED DESCRIPTION

[0016] Hereinafter, the active noise control device and the vehicle according to the present invention will be described in detail by listing preferred embodiments and referring to the drawings.

[0017] [One embodiment]

[0018] use Figure 1 to Figure 6 An active noise control device and a vehicle according to an embodiment will be described. Figure 1 It is a diagram showing an overview of active noise control.

[0019] The active noise control device 10 is a device that causes the actuator 16 to output a cancelling sound for reducing noise (vibration noise) in the cabin 14 of the vehicle 12 .

[0020] The noise in the vehicle cabin 14 may include, for example, road noise, etc. Road noise is noise caused by the wheels vibrating due to the force from the road surface, and the vibration of the wheels is transmitted to the vehicle body through the suspension and then to the passengers in the vehicle cabin 14 .

[0021] The vehicle 12 has a vibration sensor 18, more specifically, an acceleration sensor, for detecting vibration of the vehicle 12. A signal r detected by the vibration sensor 18, that is, a signal indicating the vibration, is supplied to the active noise control device 10. That is, a signal indicating the vibration is supplied to the active noise control device 10.

[0022] A microphone 20 is also provided in the vehicle cabin 14. The microphone 20 detects residual noise (cancellation error noise) generated by the interference between the cancelling sound output from the actuator 16 and the noise. The residual noise detected by the microphone 20 is supplied to the active noise control device 10. That is, the error signal e detected by the microphone 20 is supplied to the active noise control device 10.

[0023] The active noise control device 10 generates a control signal u for causing the actuator 16 to output a cancelling sound based on the signal r detected by the vibration sensor 18 and the error signal e detected by the microphone 20. More specifically, the active noise control device 10 generates the control signal u that minimizes the error signal e detected by the microphone 20. The actuator 16 outputs the cancelling sound based on the control signal u that minimizes the error signal e detected by the microphone 20, so that the noise in the vehicle cabin 14 can be well canceled by the cancelling sound. In this way, the active noise control device 10 can reduce the noise transmitted to the occupant in the vehicle cabin 14.

[0024] However, the distribution of noise in the vehicle cabin 14 differs according to the frequency of the noise. Figure 2 It is a graph showing the relationship between the frequency of noise and the magnitude of noise. Figure 3 1 is a top view showing the measurement position of noise. Point A (measurement point A) is located on the right side of the cabin 14, with the center line CL of the vehicle 12 along the front-rear direction of the vehicle 12 as the center. Point B (measurement point B) is located on the center line CL of the vehicle 12 along the front-rear direction of the vehicle 12. Point C (measurement point C) is located on the left side of the cabin 14, with the center line CL of the vehicle 12 along the front-rear direction of the vehicle 12 as the center. Figure 2 The solid line in represents the noise characteristics of the measurement point B. Figure 2 The dotted line in represents the noise characteristic of the measurement point A. Figure 2 The single-dot chain line in represents the noise characteristic of the measurement point C.

[0025] Depend on Figure 2It can be seen that the noise at the measurement points A and C and the noise at the measurement point B are significantly different in magnitude near 80 Hz and 160 Hz. The significant difference in the magnitude of the noise is due to the resonance of these frequencies in the cabin 14. In order to reliably cancel out the noise of different magnitudes distributed in the cabin 14, it is considered to detect the noise on the left side, right side, and center of the cabin 14. However, when the microphone 20 is provided on the left side, right side, and center of the cabin 14, complex control is required, resulting in an increase in design cost. In addition, when the microphone 20 is provided on the left side, right side, and center of the cabin 14, the amount of calculation becomes large, so an expensive processor is required, resulting in an increase in component cost. As a result of in-depth research by the inventors of the present application, the following active noise control device 10 was conceived.

[0026] Figure 4 It is a block diagram showing a part of a vehicle including the active noise control device according to the present embodiment. Figure 5 It is a plan view showing an example of a vehicle including the active noise control device according to the present embodiment.

[0027] like Figure 4 As shown, the active noise control device 10 includes a determination unit 26, a control unit 28, a storage unit 30, filter units 34A to 34C, and a calculation unit 44. When describing the filter unit as a whole, reference numeral 34 is used. When describing each filter unit, reference numerals 34A to 34C are used.

[0028] The active noise control device 10 has a computing device (computation processing device) not shown in the figure. The computing device can be composed of a processor such as a CPU (Central Processing Unit) and a DSP (Digital Signal Processor), but is not limited to this. The computing device can include a direct digital frequency synthesizer (DDS), a digitally controlled oscillator (DCO), etc. In addition, the computing device can include an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), etc.

[0029] As described above, the active noise control device 10 has a storage unit 30. The storage unit 30 can be composed of a volatile memory (not shown) and a non-volatile memory (not shown). Examples of volatile memory include RAM and the like. Examples of non-volatile memory include ROM, flash memory and the like. Data and the like can be stored in the volatile memory, for example. Programs, tables, maps and the like can be stored in the non-volatile memory, for example.

[0030] The determination unit 26 , the control unit 28 , the filter unit 34 , and the calculation unit 44 can be realized by causing a calculation device to execute a program stored in the storage unit 30 .

[0031] like Figure 5 As shown, the vehicle 12 can include a vibration sensor 18. The vibration sensor 18 can be, for example, an acceleration sensor, but is not limited thereto. The acceleration sensor can be, for example, a three-axis acceleration sensor, but is not limited thereto. Figure 5 Although one vibration sensor 18 is shown in the middle figure, the number of vibration sensors 18 is not limited to 1. The vibration detected by the vibration sensor 18 is supplied to the active noise control device 10 as a reference signal r.

[0032] like Figure 5 As shown in FIG. 1 , microphones 20L and 20R are provided in the vehicle compartment 14, and the microphones 20L and 20R detect residual noise generated by interference between noise and canceling sound. That is, microphones 20L and 20R are provided in the vehicle compartment 14 for detecting the error signal e. When the microphone is described as a whole, the reference numeral 20 is used. When the individual microphones are described, the reference numerals 20L and 20R are used. The center line CL of the vehicle 12 in the front-rear direction of the vehicle 12 (refer to FIG. 1 ) is shown in FIG. Figure 3 ) as the center, the microphone 20L is arranged on one side (left side) in the vehicle compartment 14. The microphone 20R is arranged on the other side (right side) in the vehicle compartment 14, centered on the center line CL of the vehicle 12 in the front-rear direction of the vehicle 12.

[0033] like Figure 5As shown, there are actuators 16L, 16R, and 16C in the vehicle compartment 14, and the actuators 16L, 16R, and 16C output canceling sounds according to the control signal u. When describing the actuator as a whole, the reference numeral 16 is used, and when describing each actuator, the reference numerals 16L, 16R, and 16C are used. The actuator 16 can be, for example, a speaker. The actuator (one side actuator) 16L is arranged on one side (left side) in the vehicle compartment 14 with the center line CL of the vehicle 12 along the front-rear direction of the vehicle 12 as the center. The actuator (the other side actuator) 16R is arranged on the other side (right side) in the vehicle compartment 14 with the center line CL of the vehicle 12 along the front-rear direction of the vehicle 12 as the center. The actuator 16C is arranged on the center line CL of the vehicle 12 along the front-rear direction of the vehicle 12. That is, the actuator 16C is arranged in the center in the vehicle width direction. The distance between the actuator 16C and the microphone 20L and the distance between the actuator 16C and the microphone 20R are the same.

[0034] like Figure 4 As shown, the filter unit 34A includes an adaptive filter 36A, acoustic characteristic filters 38A1, 38A2, and filter coefficient update units 40A1, 40A2. The filter unit 34B includes an adaptive filter 36B, acoustic characteristic filters 38B1, 38B2, and filter coefficient update units 40B1, 40B2. The filter unit 34C includes an adaptive filter 36C, an acoustic characteristic filter 38C, and a filter coefficient update unit 40C. When describing the adaptive filter as a whole, reference numeral 36 is used. When describing each adaptive filter, reference numerals 36A, 36B, and 36C are used. When describing the acoustic characteristic filter as a whole, reference numeral 38 is used. When describing each acoustic characteristic filter, reference numerals 38A1, 38A2, 38B1, 38B2, and 38C are used. When describing the filter coefficient update unit as a whole, reference numeral 40 is used. Reference numerals 40A1 , 40A2 , 40B1 , 40B2 , and 40C are used in describing the filter coefficient updating units.

[0035] The adaptive filter (second adaptive filter) 36A generates a control signal uL by filtering the reference signal r. The adaptive filter (third adaptive filter) 36B generates a control signal uR by filtering the reference signal r. The adaptive filter (first adaptive filter) 36C generates a control signal uC by filtering the reference signal r. When describing the control signal as a whole, the reference numeral u is used. When describing each control signal, the reference numerals uL, uR, and uC are used. The adaptive filter 36 can use, for example, a FIR (Finite Impulse Response) filter, but is not limited thereto. The FIR filter can generate a control signal u by performing a convolution operation on the reference signal r.

[0036] As described later, the filter coefficient W0 of the adaptive filter 36A is updated by the filter coefficient updating units 40A1 and 40A2. As described later, the filter coefficient W1 of the adaptive filter 36B is updated by the filter coefficient updating units 40B1 and 40B2. As described later, the filter coefficient W2 of the adaptive filter 36C is updated by the filter coefficient updating unit 40C. The filter coefficient W0 of the adaptive filter 36A, the filter coefficient W1 of the adaptive filter 36B, and the filter coefficient W2 of the adaptive filter 36C are different from each other. Therefore, the filtering process performed by the adaptive filter 36A, the filtering process performed by the adaptive filter 36B, and the filtering process performed by the adaptive filter 36C are different from each other.

[0037] The acoustic characteristic filter 38A1 corrects the reference signal r by performing a filtering process corresponding to the acoustic characteristic (transfer characteristic) from the actuator 16L to the microphone 20L on the reference signal r. The acoustic characteristic from the actuator 16L to the microphone 20L is acquired in advance. That is, the transfer characteristic C^00 from the actuator 16L to the microphone 20L is acquired in advance. The acoustic characteristic filter 38A2 corrects the reference signal r by performing a filtering process corresponding to the acoustic characteristic from the actuator 16L to the microphone 20R on the reference signal r. The acoustic characteristic from the actuator 16L to the microphone 20R is acquired in advance. That is, the transfer characteristic C^01 from the actuator 16L to the microphone 20R is acquired in advance.

[0038] The acoustic characteristic filter 38B1 corrects the reference signal r by performing a filtering process corresponding to the acoustic characteristics from the actuator 16R to the microphone 20L on the reference signal r. The acoustic characteristics from the actuator 16R to the microphone 20L are acquired in advance. That is, the transfer characteristic C^10 from the actuator 16R to the microphone 20L is acquired in advance. The acoustic characteristic filter 38B2 corrects the reference signal r by performing a filtering process corresponding to the acoustic characteristics from the actuator 16R to the microphone 20R on the reference signal r. The acoustic characteristics from the actuator 16R to the microphone 20R are acquired in advance. That is, the transfer characteristic C^11 from the actuator 16R to the microphone 20R is acquired in advance.

[0039] The acoustic characteristic filter 38C corrects the reference signal r by performing filtering processing corresponding to the acoustic characteristics from the actuator 16C to the microphone 20L and the acoustic characteristics from the actuator 16C to the microphone 20R. That is, the acoustic characteristic filter 38C corrects the reference signal r by performing filtering processing corresponding to the acoustic characteristics from the actuator 16C to the pair of microphones 20L, 20R. The acoustic characteristics from the actuator 16C to the microphone 20L are acquired in advance. That is, the transfer characteristic C ^20 from the actuator 16C to the microphone 20L is acquired in advance. The acoustic characteristics from the actuator 16C to the microphone 20R are acquired in advance. That is, the transfer characteristic C ^21 from the actuator 16C to the microphone 20R is acquired in advance. The acoustic characteristics from the actuator 16C to the pair of microphones 20L, 20R can be expressed by the following formula (1). That is, the transfer characteristic C^22 from the actuator 16C to the pair of microphones 20L and 20R can be expressed by the following equation (1).

[0040] C^22=C^20+C^21· · · (1)

[0041] That is, the acoustic characteristics from the actuator 16C to the pair of microphones 20L, 20R can be obtained based on the added acoustic characteristics obtained by adding the acoustic characteristics from the actuator 16C to the microphone 20L and the acoustic characteristics from the actuator 16C to the microphone 20R.

[0042] The filter coefficient updating unit 40A1 updates the filter coefficient W0 of the adaptive filter 36A based on the error signal eL obtained by detecting the residual noise through the microphone 20L and the reference signal r corrected by the acoustic characteristic filter 38A1. More specifically, the filter coefficient updating unit 40A1 updates the filter coefficient W0 of the adaptive filter 36A so as to minimize the error signal eL obtained by detecting the residual noise through the microphone 20L.

[0043] The filter coefficient updating unit 40A2 updates the filter coefficient W0 of the adaptive filter 36A based on the error signal eR obtained by detecting the residual noise through the microphone 20R and the reference signal r corrected by the acoustic characteristic filter 38A2. More specifically, the filter coefficient updating unit 40A2 updates the filter coefficient W0 of the adaptive filter 36A so that the error signal eR obtained by detecting the residual noise through the microphone 20R is minimized.

[0044] When describing the error signal as a whole, the reference numeral e is used, and when describing each error signal, the reference numerals eL, eR, and eC are used. When describing the filter coefficient as a whole, the reference numeral W is used. When describing each filter coefficient, the reference numerals W0, W1, and W2 are used. When updating the filter coefficient W, for example, the Filtered-XLMS algorithm can be used, but it is not limited to this.

[0045] The filter coefficient updating unit 40B1 updates the filter coefficient W1 of the adaptive filter 36B based on the error signal eL obtained by detecting the residual noise through the microphone 20L and the reference signal r corrected by the acoustic characteristic filter 38B1. More specifically, the filter coefficient updating unit 40B1 updates the filter coefficient W1 of the adaptive filter 36B so that the error signal eL obtained by detecting the residual noise through the microphone 20L is minimized.

[0046] The filter coefficient updating unit 40B2 updates the filter coefficient W1 of the adaptive filter 36B based on the error signal eR obtained by detecting the residual noise through the microphone 20R and the reference signal r corrected by the acoustic characteristic filter 38B2. More specifically, the filter coefficient updating unit 40B2 updates the filter coefficient W1 of the adaptive filter 36B so that the error signal eR obtained by detecting the residual noise through the microphone 20R is minimized.

[0047] The calculation unit 44 adds the error signal eL obtained by detecting the residual noise by the microphone 20L and the error signal eR obtained by detecting the residual noise by the microphone 20R. The calculation unit (adder) 44 supplies the added error signal eC obtained by adding the error signal eL and the error signal eR to the filter coefficient update unit 40C.

[0048] Figure 6 is a graph showing an example of an added error signal. Figure 6 The horizontal axis in represents frequency, Figure 6 The vertical axis represents the size of the signal. Figure 6The solid line in represents a value obtained by dividing the added value obtained by adding the error signal eL obtained by detecting the residual noise by the microphone 20L and the error signal eR obtained by detecting the residual noise by the microphone 20R. That is, Figure 6 The solid line in φ is an average value of the error signal eL obtained by detecting the residual noise by the microphone 20L and the error signal eR obtained by detecting the residual noise by the microphone 20R. Figure 6 The dotted line in represents the residual noise detected by the microphone when the microphone is arranged in the center of the vehicle width direction. Figure 6 Therefore, even if the addition error signal eC obtained by adding the error signal eL detected by the microphone 20L and the error signal eR detected by the microphone 20R is used, there will be no particular problem in the accuracy of suppressing noise.

[0049] The filter coefficient updating unit 40C updates the filter coefficient W2 of the adaptive filter 36C based on the added error signal eC supplied from the operation unit 44 and the reference signal r corrected by the acoustic characteristic filter 38C. More specifically, the filter coefficient updating unit 40C updates the filter coefficient W2 of the adaptive filter 36C so as to minimize the added error signal eC.

[0050] The control signal uL output by the adaptive filter 36A is supplied to the actuator 16L through the power amplifier 15L. That is, the control signal uL output by the filter unit 34A is supplied to the actuator 16L through the power amplifier 15L. The control signal uR output by the adaptive filter 36B is supplied to the actuator 16R through the power amplifier 15R. That is, the control signal uR output by the filter unit 34B is supplied to the actuator 16R through the power amplifier 15R. The control signal uC output by the adaptive filter 36C is supplied to the actuator 16C through the power amplifier 15C. That is, the control signal uC output by the filter unit 34B is supplied to the actuator 16C through the power amplifier 15C.

[0051] The determination unit (abnormality determination unit) 26 can determine whether an abnormality occurs in either the error signal eL acquired by the microphone 20L or the error signal eR acquired by the microphone 20R. Examples of such abnormality include, but are not limited to, disconnection of the wiring between the microphone 20 and the active noise control device 10 and failure of the microphone 20. When the magnitude of the error signal eL is greater than the volume threshold value VTH and the magnitude of the error signal eR is less than the volume threshold value VTH, and this state lasts for a period of time greater than the threshold value TTH, the determination unit 26 makes the following determination. That is, in this case, the determination unit 26 determines that an abnormality occurs in the error signal eR acquired by the microphone 20R. When the magnitude of the error signal eR is greater than the volume threshold value VTH and the magnitude of the error signal eL is less than the volume threshold value VTH, and this state lasts for a period of time greater than the threshold value TTH, the determination unit 26 makes the following determination. That is, in this case, the determination unit 26 determines that an abnormality occurs in the error signal eL acquired by the microphone 20L. The determination result of the determination unit 26 is supplied to the control unit 28.

[0052] When the determination unit 26 determines that one of the error signal eL and the error signal eR is abnormal, the control unit 28 can perform the following control. That is, in this case, the control unit 28 causes the filter coefficient update unit 40C to update the filter coefficient W2 of the adaptive filter 36C based on the other of the error signal eL and the error signal eR and the reference signal r corrected by the acoustic characteristic filter 38C.

[0053] Next, use Figure 7 An example of the operation of the active noise control device according to the present embodiment will be described. Figure 7 : is a flowchart showing an example of the operation of the active noise control device according to the present embodiment.

[0054] First, in step S1, the determination unit 26 determines whether an abnormality occurs in the error signal eL. If an abnormality occurs in the error signal eL (Yes in step S1), the process proceeds to step S3. If an abnormality occurs in the error signal eL (No in step S1), the process proceeds to step S2.

[0055] In step S2, the determination unit 26 determines whether an abnormality occurs in the error signal eR. If an abnormality occurs in the error signal eR (yes in step S2), the process proceeds to step S4. If an abnormality occurs in the error signal eR (no in step S2), the process proceeds to step S4. Figure 7 The indicated processing is completed.

[0056] In step S3 , the control unit 28 causes the filter coefficient updating unit 40C to update the filter coefficient W2 of the adaptive filter 36C based on the reference signal r and the error signal eR corrected by the acoustic characteristics filter 38C.

[0057] In step S4 , the control unit 28 causes the filter coefficient updating unit 40C to update the filter coefficient W2 of the adaptive filter 36C based on the reference signal r and the error signal eL corrected by the acoustic characteristics filter 38C.

[0058] In this way, Figure 7 The indicated processing is completed.

[0059] Thus, in the present embodiment, the error signal eL detected by the microphone 20L arranged on one side and the error signal eR detected by the microphone 20R arranged on the other side are added to obtain the added error signal eC. The added error signal eC corresponds to the residual noise in the center of the vehicle width direction. And the filter coefficient W2 of the adaptive filter 36C is updated so that the added error signal eC obtained in this way is minimized. According to the present embodiment, the residual noise in the center of the vehicle width direction can be reliably reduced without setting up another microphone in the center of the vehicle width direction. According to the present embodiment, the complexity of the control can be suppressed, so the design cost can be suppressed. In addition, according to the present embodiment, the increase in the amount of calculation can be suppressed, so that the cost of parts can be suppressed without the need for an expensive processor. Therefore, according to the present embodiment, it is possible to provide an active noise control device 10 that can reduce noise well and can achieve low cost.

[0060] [Modified embodiment]

[0061] As mentioned above, although the preferred embodiment of the present invention is described, the present invention is not limited to the above-mentioned embodiment, and various changes can be made within the scope not departing from the gist of the present invention.

[0062] For example, in the above embodiment, the case where the central actuator 16C is provided is described as an example, but the central actuator 16C may not be provided. In this case, the same control signal may be supplied to the one-side actuator 16L and the other-side actuator 16R. That is, if a pair of actuators 16L and 16R output a monophonic sound, the central actuator 16C may not be provided. However, from the viewpoint of more effectively reducing noise, it is preferable to provide the central actuator 16C.

[0063] The above-mentioned implementation modes are summarized as follows.

[0064] An active noise control device (10) is provided to reduce noise in a vehicle cabin (14) of a vehicle (12) so that an actuator (16C) outputs a cancelling sound according to a control signal (uC). The active noise control device (10) comprises a first adaptive filter (34C) and a first filter coefficient updating unit (40C), wherein the first adaptive filter (34C) generates the control signal by filtering a reference signal (r) corresponding to the noise; and the first filter coefficient updating unit (40C) updates the filter coefficient (W2) of the first adaptive filter according to an addition error signal (eC) and the reference signal. The difference signal (eC) is a signal obtained by adding a first error signal (eL) and a second error signal (eR), wherein the first error signal (eL) is obtained by detecting residual noise generated by interference between the noise and the canceling sound by a first microphone (20L), the first microphone (20L) being arranged on one side of the vehicle compartment with the center line (CL) of the vehicle along the front-rear direction of the vehicle as the center; and the second error signal (eR) is obtained by detecting the residual noise by a second microphone (20R), the second microphone (20R) being arranged on the other side of the vehicle compartment with the center line of the vehicle as the center. According to this structure, an addition error signal corresponding to the residual noise at the center in the vehicle width direction is obtained by adding the first error signal detected by the first microphone arranged on one side and the second error signal detected by the second microphone arranged on the other side. And the filter coefficient of the first adaptive filter is updated so that the addition error signal obtained in this way is minimized. According to this structure, the residual noise in the center of the vehicle width direction can be reliably reduced without setting up a microphone in the center of the vehicle width direction. According to this structure, the complexity of control can be suppressed, so the design cost can be suppressed. In addition, according to this structure, the increase in the amount of calculation can be suppressed, so an expensive processor is not required, and the cost of parts can be suppressed. Therefore, according to this structure, it is possible to provide an active noise control device that can effectively reduce noise and achieve low cost.

[0065] It is also possible to further include a first acoustic characteristic filter (38C) that corrects the reference signal by performing filtering processing corresponding to a first acoustic characteristic and a second acoustic characteristic on the reference signal, wherein the first acoustic characteristic is an acoustic characteristic (C^20) from the actuator to the first microphone, and the second acoustic characteristic is an acoustic characteristic (C^21) from the actuator to the second microphone, and the first filter coefficient updating unit updates the filter coefficient of the first adaptive filter based on the addition error signal and the reference signal corrected by the first acoustic characteristic filter. According to this structure, the first acoustic characteristic filter performs filtering processing corresponding to the acoustic characteristic from the actuator to a pair of microphones, so that the amount of calculation can be suppressed and noise can be effectively suppressed.

[0066] The present invention may further include a determination unit (26) for determining whether an abnormality occurs in either of the first error signal and the second error signal, and a control unit (28) for causing the first filter coefficient updating unit to update the filter coefficient of the first adaptive filter based on the other of the first error signal and the second error signal and the reference signal corrected by the first acoustic characteristic filter when the determination unit determines that an abnormality occurs in either of the first error signal and the second error signal. According to this structure, even when an abnormality occurs in either of the pair of microphones, it is possible to reduce noise well while suppressing adverse effects of the abnormal microphone.

[0067] The actuator may be provided at the center in the vehicle width direction. According to this structure, an active noise control device capable of effectively reducing noise in a vehicle cabin can be provided.

[0068] It may also be that it further comprises a second adaptive filter (36A), a second acoustic characteristic filter (38A1), a second filter coefficient updating unit (40A1), a third acoustic characteristic filter (38A2), a third filter coefficient updating unit (40A2), a third adaptive filter (36B), a fourth acoustic characteristic filter (38B1), a fourth filter coefficient updating unit (40B1), a fifth acoustic characteristic filter (38B2) and a fifth filter coefficient updating unit (40B2), wherein the second adaptive filter (36A) generates a reference signal for supplying to one side actuator (16L) by performing filtering processing on the reference signal that is different from the filtering processing performed by the first adaptive filter. The control signal (uL) given is taken as the center line of the vehicle, and the one-side actuator (16L) is arranged on the one side in the vehicle compartment; the second acoustic characteristic filter (38A1) corrects the reference signal by filtering the reference signal corresponding to the acoustic characteristics (C^00) from the one-side actuator to the first microphone; the second filter coefficient updating unit (40A1) updates the filter coefficient (W0) of the second adaptive filter according to the first error signal and the reference signal corrected by the second acoustic characteristic filter; the third acoustic characteristic filter (38A2) corrects the reference signal by filtering the reference signal corresponding to the acoustic characteristics (C^00) from the one-side actuator to the first microphone The reference signal is corrected by filtering processing corresponding to the acoustic characteristics (C^01) of the second microphone; the third filter coefficient updating unit (40A2) updates the filter coefficient of the second adaptive filter according to the second error signal and the reference signal corrected by the third acoustic characteristic filter; the third adaptive filter (36B) generates a control signal (uR) supplied to the other side actuator (16R) by filtering the reference signal differently from the filtering processing performed by the first adaptive filter and the filtering processing performed by the second adaptive filter, wherein the other side actuator (16R) is centered on the center line of the vehicle. The fourth acoustic characteristic filter (38B1) corrects the reference signal by filtering the reference signal in accordance with the acoustic characteristic (C^10) from the actuator on the other side to the first microphone; the fourth filter coefficient updating unit (40B1) updates the filter coefficient (W1) of the third adaptive filter according to the first error signal and the reference signal corrected by the fourth acoustic characteristic filter; the fifth acoustic characteristic filter (38B2) corrects the reference signal by filtering the reference signal in accordance with the acoustic characteristic (C^11) from the actuator on the other side to the second microphone;The fifth filter coefficient updating unit (40B2) updates the filter coefficient of the third adaptive filter based on the second error signal and the reference signal corrected by the fifth acoustic characteristic filter. According to this structure, an active noise control device capable of effectively reducing noise can be provided.

[0069] Alternatively, the actuator may include a one-side actuator and an other-side actuator, wherein the one-side actuator is disposed on the one side in the vehicle compartment with the center line of the vehicle as the center, and the other-side actuator is disposed on the other side in the vehicle compartment with the center line of the vehicle as the center, and the same control signal is supplied to the one-side actuator and the other-side actuator. According to this structure, it is not necessary to provide an actuator in the center in the vehicle width direction, thereby contributing to cost reduction.

[0070] A vehicle has the above-mentioned active noise control device.

Claims

1. An active noise control device (10) which causes an actuator (16C) to output a cancelling sound based on a control signal (uC) to reduce noise in a cabin (14) of a vehicle (12), It is characterized in that A first adaptive filter (34C) and a first filter coefficient updating unit (40C) are provided, wherein: The first adaptive filter (34C) generates the control signal by filtering a reference signal (r) corresponding to the noise; The first filter coefficient updating unit (40C) updates the filter coefficient (W2) of the first adaptive filter according to an addition error signal (eC) and the reference signal, wherein the addition error signal (eC) is a signal obtained by adding a first error signal (eL) and a second error signal (eR), wherein the first error signal (eL) is obtained by detecting residual noise generated by interference between the noise and the canceling sound by a first microphone (20L), and the first microphone (20L) is arranged on one side of the vehicle cabin with a center line (CL) of the vehicle along the front-rear direction of the vehicle as the center; and the second error signal (eR) is obtained by detecting the residual noise by a second microphone (20R), and the second microphone (20R) is arranged on the other side of the vehicle cabin with the center line of the vehicle as the center.

2. The active noise control device according to claim 1, characterized in that: The invention also comprises a first acoustic characteristic filter (38C) which corrects the reference signal by filtering the reference signal according to a first acoustic characteristic and a second acoustic characteristic, wherein the first acoustic characteristic refers to an acoustic characteristic (C^20) from the actuator to the first microphone, and the second acoustic characteristic refers to an acoustic characteristic (C^21) from the actuator to the second microphone. The first filter coefficient updating unit updates the filter coefficient of the first adaptive filter based on the added error signal and the reference signal corrected by the first acoustic characteristic filter.

3. The active noise control device according to claim 2, characterized in that: The device further comprises a determination unit (26) for determining whether an abnormality occurs in either the first error signal or the second error signal. It also has a control unit (28) which, when the determination unit determines that one of the first error signal and the second error signal is abnormal, causes the first filter coefficient updating unit to update the filter coefficient of the first adaptive filter based on the other of the first error signal and the second error signal and the reference signal corrected by the first acoustic characteristic filter.

4. The active noise control device according to claim 2, characterized in that: The actuator is disposed at the center in the vehicle width direction.

5. The active noise control device according to claim 4, characterized in that: The system further comprises a second adaptive filter (36A), a second acoustic characteristic filter (38A1), a second filter coefficient updating unit (40A1), a third acoustic characteristic filter (38A2), a third filter coefficient updating unit (40A2), a third adaptive filter (36B), a fourth acoustic characteristic filter (38B1), a fourth filter coefficient updating unit (40B1), a fifth acoustic characteristic filter (38B2) and a fifth filter coefficient updating unit (40B2), wherein: The second adaptive filter (36A) generates a control signal (uL) supplied to a one-side actuator (16L) by performing filtering processing on the reference signal that is different from the filtering processing performed by the first adaptive filter, the one-side actuator (16L) being arranged on the one side in the vehicle cabin with the center line of the vehicle as the center; The second acoustic characteristic filter (38A1) corrects the reference signal by performing filtering processing corresponding to the acoustic characteristic (C^00) from the one-side actuator to the first microphone on the reference signal; The second filter coefficient updating unit (40A1) updates the filter coefficient (W0) of the second adaptive filter based on the first error signal and the reference signal corrected by the second acoustic characteristic filter; The third acoustic characteristic filter (38A2) corrects the reference signal by performing filtering processing on the reference signal corresponding to the acoustic characteristic (C^01) from the one-side actuator to the second microphone; The third filter coefficient updating unit (40A2) updates the filter coefficient of the second adaptive filter based on the second error signal and the reference signal corrected by the third acoustic characteristic filter; The third adaptive filter (36B) generates a control signal (uR) supplied to the other side actuator (16R) by performing filtering processing on the reference signal that is different from both the filtering processing performed by the first adaptive filter and the filtering processing performed by the second adaptive filter, wherein the other side actuator (16R) is arranged on the other side in the vehicle cabin with the center line of the vehicle as the center; The fourth acoustic characteristic filter (38B1) corrects the reference signal by performing filtering processing corresponding to the acoustic characteristic (C^10) from the other-side actuator to the first microphone on the reference signal; The fourth filter coefficient updating unit (40B1) updates the filter coefficient (W1) of the third adaptive filter based on the first error signal and the reference signal corrected by the fourth acoustic characteristic filter; The fifth acoustic characteristic filter (38B2) corrects the reference signal by performing filtering processing corresponding to the acoustic characteristic (C^11) from the other side actuator to the second microphone on the reference signal; The fifth filter coefficient updating unit (40B2) updates the filter coefficient of the third adaptive filter based on the second error signal and the reference signal corrected by the fifth acoustic characteristics filter.

6. The active noise control device according to claim 2, characterized in that: The actuator includes a one-side actuator and an other-side actuator, wherein the one-side actuator is arranged on the one side in the vehicle compartment with the center line of the vehicle as the center; and the other-side actuator is arranged on the other side in the vehicle compartment with the center line of the vehicle as the center. The same control signal is supplied to the one-side actuator and the other-side actuator.

7. A vehicle, characterized in that: An active noise control device according to any one of claims 1 to 6.

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