Active noise control device and vehicle

Abstract

To provide an active noise controller capable of excellently reducing noise and a vehicle.SOLUTION: An active noise controller 10 comprises: a first adaptive filter 36C that generates control signals uC by performing filtering processing on reference signals r in response to noise; and a first filter coefficient update unit 40C that updates a filter coefficient W2 in the first adaptive filter, on the basis of additional error signals eC obtained by adding a first error signals eL acquired by detecting residual noise with a first microphone 20L and a second error signals eR acquired by detecting the residual noise with a second microphone 20R and the reference signals r.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Patent Document 1 discloses an in-vehicle noise reduction device that includes a control block that generates a cancellation signal based on vibrations detected by multiple vibration sensors, multiple speakers that emit cancellation vibrations based on the cancellation signal, and multiple microphones that detect cancellation errors between the cancellation vibrations and vibrations from a vibration source. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-265471 Summary of the Invention [Problem to be solved by the invention]

[0004] However, an active noise control system that handles inputs from multiple vibration sensors, outputs from multiple speakers, and inputs from multiple microphones requires complex control, which increases design costs, and the large amount of calculation required for such an active noise control system requires an expensive processor, which increases component costs.

[0005] An object of the present invention is to provide an active noise control device and a vehicle that can effectively reduce noise and achieve low costs. [Means for solving the problem]

[0006] An active noise control device according to one embodiment of the present invention is an active noise control device that outputs a canceling sound based on a control signal from an actuator in order to reduce noise inside a vehicle cabin, and includes a first adaptive filter that generates the control signal by performing a filtering process on a reference signal corresponding to the noise, and a first filter coefficient update unit that updates a filter coefficient in the first adaptive filter based on a sum error signal obtained by adding together a first error signal obtained by detecting residual noise due to interference between the noise and the canceling sound using a first microphone arranged on one side of the cabin centered on a center line of the vehicle along the longitudinal direction of the vehicle, and a second error signal obtained by detecting the residual noise using a second microphone arranged on the other side of the cabin centered on the center line of the vehicle, and the reference signal.

[0007] A vehicle according to another aspect of the present invention includes an active noise control device as described above. Effect of the Invention

[0008] 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 low costs. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an overview of active noise control. [Diagram 2] 1 is a graph showing the relationship between noise frequency and noise volume. [Diagram 3] FIG. 2 is a plan view showing the locations where noise was measured. [Figure 4] 1 is a block diagram showing a portion of a vehicle equipped with an active noise control device according to an embodiment; [Diagram 5] 1 is a plan view showing an example of a vehicle equipped with an active noise control device according to an embodiment. [Figure 6] 11 is a graph showing an example of a summed error signal. [Figure 7]4 is a flowchart showing an example of the operation of the active noise control device according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An active noise control device and a vehicle according to the present invention will be described in detail below with reference to preferred embodiments and the accompanying drawings.

[0011] [One embodiment] An active noise control device and a vehicle according to an embodiment will be described with reference to Figures 1 to 6. Figure 1 is a diagram showing an overview of active noise control.

[0012] The active noise control system 10 causes an actuator 16 to output a canceling sound for reducing noise, i.e., vibration noise, within a passenger compartment 14 of a vehicle 12.

[0013] Noises inside the vehicle cabin 14 may include, for example, road noise. Road noise is noise that is transmitted to passengers inside the vehicle cabin 14 when the wheels vibrate due to the force they receive from the road surface and the wheel vibrations are transmitted to the vehicle body via the suspension.

[0014] The vehicle 12 is provided with a vibration sensor 18, more specifically, an acceleration sensor, that detects vibrations of the vehicle 12. A signal r detected by the vibration sensor 18, i.e., a signal indicative of the vibration, is supplied to the active noise control device 10.

[0015] A microphone 20 is further provided in the vehicle compartment 14. The microphone 20 detects residual noise (cancellation error noise) resulting from interference between the canceling sound output from the actuator 16 and the noise. The residual noise detected by the microphone 20, i.e., the error signal e, is supplied to the active noise control device 10.

[0016] The active noise control device 10 generates a control signal u for outputting a canceling sound from the actuator 16, 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 a control signal u such that the error signal e detected by the microphone 20 is minimized. Since the actuator 16 outputs a canceling sound based on the control signal u such that the error signal e detected by the microphone 20 is minimized, the noise inside the vehicle compartment 14 can be effectively cancelled out by the canceling sound. In this way, the active noise control device 10 can reduce the noise transmitted to the occupants inside the vehicle compartment 14.

[0017] Incidentally, the distribution of noise in the vehicle compartment 14 differs depending on the frequency of the noise. FIG. 2 is a graph showing the relationship between the frequency of the noise and the noise volume. FIG. 3 is a plan view showing the locations where the noise was measured. Point A, i.e., measurement point A, is located on the right side of the vehicle compartment 14, centered on the center line CL of the vehicle 12 along the front-rear direction of the vehicle 12. Point B, i.e., 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, i.e., measurement point C, is located on the left side of the vehicle compartment 14, centered on the center line CL of the vehicle 12 along the front-rear direction of the vehicle 12. The solid line in FIG. 2 indicates the noise characteristics at measurement point B, the dotted line in FIG. 2 indicates the noise characteristics at measurement point A, and the dashed-dotted line in FIG. 2 indicates the noise characteristics at measurement point C.

[0018] As can be seen from FIG. 2, the noise levels at measurement points A and C are significantly different from that at measurement point B at frequencies around 80 Hz and 160 Hz. Such significant differences in noise levels are due to resonance at these frequencies occurring in the vehicle interior 14. It is conceivable to detect noises at the left, right, and center of the vehicle interior 14 in order to accurately cancel out noises with different noise level distributions in the vehicle interior 14. However, when microphones 20 are provided at all of the left, right, and center of the vehicle interior 14, complex control is required, which increases design costs. Furthermore, when microphones 20 are provided at all of the left, right, and center of the vehicle interior 14, the amount of calculation increases, which requires an expensive processor, which increases component costs. After extensive research, the present inventor has come up with the following active noise control device 10.

[0019] Fig. 4 is a block diagram showing a part of a vehicle equipped with an active noise control device according to the present embodiment. Fig. 5 is a plan view showing an example of a vehicle equipped with an active noise control device according to the present embodiment.

[0020] 4, the active noise control device 10 includes a determination section 26, a control section 28, a storage section 30, filter sections 34A to 34C, and a calculation section 44. When describing the filter section in general, reference numeral 34 will be used, and when describing each individual filter section, reference numerals 34A to 34C will be used.

[0021] The active noise control device 10 is provided with a calculation device (arithmetic processing device) (not shown). The calculation device may be configured with a processor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor), but is not limited to this. A direct digital synthesizer (DDS), a digitally controlled oscillator (DCO), etc. may be included in the calculation device. In addition, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc. may be included in the calculation device.

[0022] As described above, the active noise control device 10 is provided with the memory unit 30. The memory unit 30 may be composed of a volatile memory (not shown) and a non-volatile memory (not shown). The volatile memory may be, for example, a RAM. The non-volatile memory may be, for example, a ROM, a flash memory. Data, etc. may be stored in, for example, the volatile memory. Programs, tables, maps, etc. may be stored in, for example, the non-volatile memory.

[0023] The determination unit 26, the control unit 28, the filter unit 34, and the calculation unit 44 can be realized by a program stored in the storage unit 30 being executed by a calculation device.

[0024] As shown in Fig. 5, the vehicle 12 may be provided with a vibration sensor 18. As the vibration sensor 18, for example, an acceleration sensor may be used, but is not limited to this. As the acceleration sensor, for example, a three-axis acceleration sensor may be used, but is not limited to this. In Fig. 5, one vibration sensor 18 is illustrated, but the number of vibration sensors 18 is not limited to one. The vibration detected by the vibration sensor 18 is supplied to the active noise control device 10 as a reference signal r.

[0025] As shown in Fig. 5, microphones 20L and 20R are provided in the vehicle interior 14 to detect residual noise caused by interference between the noise and the canceling sound, i.e., error signal e. Reference numeral 20 will be used to generally describe the microphones, and reference numerals 20L and 20R will be used to describe each individual microphone. The microphone 20L is provided on one side of the vehicle interior 14, i.e., on the left side, centered on the center line CL of the vehicle 12 (see Fig. 3) that runs along the front-rear direction of the vehicle 12. The microphone 20R is provided on the other side of the vehicle interior 14, i.e., on the right side, centered on the center line CL of the vehicle 12 that runs along the front-rear direction of the vehicle 12.

[0026] As shown in FIG. 5, the vehicle interior 14 is provided with actuators 16L, 16R, and 16C that output canceling sounds based on a control signal u. When describing actuators in general, reference symbol 16 is used, and when describing each actuator, reference symbols 16L, 16R, and 16C are used. The actuator 16 may be, for example, a speaker. The actuator 16L, i.e., the one-side actuator, is provided on one side of the vehicle interior 14, i.e., on the left side, centered on the center line CL of the vehicle 12 along the longitudinal direction of the vehicle 12. The actuator 16R, i.e., the other-side actuator, is provided on the other side of the vehicle interior 14, i.e., on the right side, centered on the center line CL of the vehicle 12 along the longitudinal direction of the vehicle 12. The actuator 16C, i.e., the central actuator, is provided on the center line CL of the vehicle 12 along the longitudinal direction of the vehicle 12, i.e., 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 equal to each other.

[0027] As shown in FIG. 4, the filter unit 34A includes an adaptive filter 36A, acoustic characteristic filters 38A1 and 38A2, and filter coefficient update units 40A1 and 40A2. The filter unit 34B includes an adaptive filter 36B, acoustic characteristic filters 38B1 and 38B2, and filter coefficient update units 40B1 and 40B2. The filter unit 34C includes an adaptive filter 36C, acoustic characteristic filter 38C, and filter coefficient update unit 40C. When describing adaptive filters in general, reference symbol 36 is used, and when describing individual adaptive filters, reference symbols 36A, 36B, and 36C are used. When describing acoustic characteristic filters in general, reference symbol 38 is used, and when describing individual acoustic characteristic filters, reference symbols 38A1, 38A2, 38B1, 38B2, and 38C are used. When describing the filter coefficient update unit in general, the reference numeral 40 will be used, and when describing each of the filter coefficient update units, the reference numerals 40A1, 40A2, 40B1, 40B2, and 40C will be used.

[0028] The adaptive filter (second adaptive filter) 36A generates a control signal uL by performing a filtering process on the reference signal r. The adaptive filter (third adaptive filter) 36B generates a control signal uR by performing a filtering process on the reference signal r. The adaptive filter (first adaptive filter) 36C generates a control signal uC by performing a filtering process on the reference signal r. When describing control signals in general, the symbol u is used, and when describing individual control signals, the symbols uL, uR, and uC are used. As the adaptive filter 36, for example, a FIR (Finite Impulse Response) filter or the like can be used, but is not limited thereto. The FIR filter can generate the control signal u by performing a convolution operation on the reference signal r.

[0029] The filter coefficient W0 in the adaptive filter 36A is updated by filter coefficient update units 40A1 and 40A2, as described later. The filter coefficient W1 in the adaptive filter 36B is updated by filter coefficient update units 40B1 and 40B2, as described later. The filter coefficient W2 in the adaptive filter 36C is updated by filter coefficient update unit 40C, as described later. The filter coefficient W0 in the adaptive filter 36A, the filter coefficient W1 in the adaptive filter 36B, and the filter coefficient W2 in 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.

[0030] The acoustic characteristic filter 38A1 corrects the reference signal r by performing a filtering process on the reference signal r according to the acoustic characteristic (transfer characteristic) from the actuator 16L to the microphone 20L. The acoustic characteristic from the actuator 16L to the microphone 20L, i.e., the transfer characteristic C^00, is acquired in advance. The acoustic characteristic filter 38A2 corrects the reference signal r by performing a filtering process on the reference signal r according to the acoustic characteristic from the actuator 16L to the microphone 20R. The acoustic characteristic from the actuator 16L to the microphone 20R, i.e., the transfer characteristic C^01, is acquired in advance.

[0031] The acoustic characteristic filter 38B1 corrects the reference signal r by performing a filtering process on the reference signal r according to the acoustic characteristics from the actuator 16R to the microphone 20L. The acoustic characteristics from the actuator 16R to the microphone 20L, i.e., the transfer characteristic C^10, are acquired in advance. The acoustic characteristic filter 38B2 corrects the reference signal r by performing a filtering process on the reference signal r according to the acoustic characteristics from the actuator 16R to the microphone 20R. The acoustic characteristics from the actuator 16R to the microphone 20R, i.e., the transfer characteristic C^11, are acquired in advance.

[0032] The acoustic characteristic filter 38C corrects the reference signal r by performing a filtering process on the reference signal r according 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 a filtering process on the reference signal r according to the acoustic characteristics from the actuator 16C to the pair of microphones 20L and 20R. The acoustic characteristics from the actuator 16C to the microphone 20L, that is, the transfer characteristic C^20, are acquired in advance. The acoustic characteristics from the actuator 16C to the microphone 20R, that is, the transfer characteristic C^21, are acquired in advance. The acoustic characteristics from the actuator 16C to the pair of microphones 20L and 20R, that is, the transfer characteristic C^22, can be expressed by the following formula (1).

[0033] C^22=C^20+C^21 (1)

[0034] That is, the acoustic characteristics from the actuator 16C to the pair of microphones 20L, 20R are obtained based on an added acoustic characteristic obtained by adding together the acoustic characteristics from the actuator 16C to the microphone 20L and the acoustic characteristics from the actuator 16C to the microphone 20R.

[0035] The filter coefficient update unit 40A1 updates the filter coefficient W0 in the adaptive filter 36A based on the error signal eL obtained by detecting the residual noise with the microphone 20L and the reference signal r corrected by the acoustic characteristics filter 38A1. More specifically, the filter coefficient update unit 40A1 updates the filter coefficient W0 in the adaptive filter 36A so that the error signal eL obtained by detecting the residual noise with the microphone 20L is minimized.

[0036] The filter coefficient update unit 40A2 updates the filter coefficient W0 in the adaptive filter 36A based on the error signal eR obtained by detecting the residual noise with the microphone 20R and the reference signal r corrected by the acoustic characteristics filter 38A2. More specifically, the filter coefficient update unit 40A2 updates the filter coefficient W0 in the adaptive filter 36A so that the error signal eR obtained by detecting the residual noise with the microphone 20R is minimized.

[0037] When describing error signals in general, the symbol e is used, and when describing individual error signals, the symbols eL, eR, and eC are used. When describing filter coefficients in general, the symbol W is used, and when describing individual filter coefficients, the symbols W0, W1, and W2 are used. In updating the filter coefficient W, for example, a Filtered-X LMS algorithm can be used, but is not limited to this.

[0038] The filter coefficient update unit 40B1 updates the filter coefficient W1 in the adaptive filter 36B based on the error signal eL obtained by detecting the residual noise with the microphone 20L and the reference signal r corrected by the acoustic characteristics filter 38B1. More specifically, the filter coefficient update unit 40B1 updates the filter coefficient W1 in the adaptive filter 36B so that the error signal eL obtained by detecting the residual noise with the microphone 20L is minimized.

[0039] The filter coefficient update unit 40B2 updates the filter coefficient W1 in the adaptive filter 36B based on the error signal eR obtained by detecting the residual noise with the microphone 20R and the reference signal r corrected by the acoustic characteristics filter 38B2. More specifically, the filter coefficient update unit 40B2 updates the filter coefficient W1 in the adaptive filter 36B so that the error signal eR obtained by detecting the residual noise with the microphone 20R is minimized.

[0040] The calculation unit 44 adds together an error signal eL obtained by detecting the residual noise with the microphone 20L and an error signal eR obtained by detecting the residual noise with the microphone 20R. The calculation unit 44, i.e., the adder, supplies a sum error signal eC obtained by adding the error signal eL and the error signal eR to the filter coefficient update unit 40C.

[0041] FIG. 6 is a graph showing an example of an added error signal. The horizontal axis in FIG. 6 indicates frequency, and the vertical axis in FIG. 6 indicates signal magnitude. The solid line in FIG. 6 is obtained by adding together the error signal eL obtained by detecting the residual noise with microphone 20L and the error signal eR obtained by detecting the residual noise with microphone 20R, and dividing the added value by two. In other words, the solid line in FIG. 6 is the average value of the error signal eL obtained by detecting the residual noise with microphone 20L and the error signal eR obtained by detecting the residual noise with microphone 20R. The dotted line in FIG. 6 indicates the residual noise detected by a microphone when that microphone is placed at the center in the vehicle width direction. vinegar. As can be seen from Fig. 6, the difference between the two is extremely small. Therefore, even if the added 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, no particular problem occurs in the accuracy of noise suppression.

[0042] The filter coefficient update unit 40C updates the filter coefficient W2 in the adaptive filter 36C based on the added error signal eC supplied from the calculation unit 44 and the reference signal r corrected by the acoustic characteristics filter 38C. More specifically, the filter coefficient update unit 40C updates the filter coefficient W2 in the adaptive filter 36C so that the added error signal eC is minimized.

[0043] The control signal uL output from the adaptive filter 36A, i.e., the control signal uL output from the filter unit 34A, is supplied to the actuator 16L via the power amplifier 15L. The control signal uR output from the adaptive filter 36B, i.e., the control signal uR output from the filter unit 34B, is supplied to the actuator 16R via the power amplifier 15R. The control signal uC output from the adaptive filter 36C, i.e., the control signal uC output from the filter unit 34B, is supplied to the actuator 16C via the power amplifier 15C.

[0044] 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 abnormalities include, but are not limited to, a break in the wiring between the microphone 20 and the active noise control device 10, a malfunction of the microphone 20, and the like. When the magnitude of the error signal eL is equal to or greater than the volume threshold VTH, the magnitude of the error signal eR is less than the volume threshold VTH, and such a state continues for a time threshold TTH or more, the determination unit 26 performs the following determination. That is, in such a 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 equal to or greater than the volume threshold VTH, the magnitude of the error signal eL is less than the volume threshold VTH, and such a state continues for a time threshold TTH or more, the determination unit 26 performs the following determination. That is, in such a case, the determination unit 26 determines that an abnormality has occurred in the error signal eL acquired by the microphone 20L. The determination result by the determination unit 26 is supplied to the control unit .

[0045] When the determining unit 26 determines that an abnormality has occurred in one of the error signals eL and eR, the control unit 28 can perform the following control: That is, in such a case, the control unit 28 causes the filter coefficient W2 in the adaptive filter 36C to be updated by the filter coefficient updating unit 40C based on the other of the error signals eL and eR and the reference signal r corrected by the acoustic characteristics filter 38C.

[0046] Next, an example of the operation of the active noise control device according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of the operation of the active noise control device according to this embodiment.

[0047] First, in step S1, the judgment unit 26 judges whether or not 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 does not occur in the error signal eL (NO in step S1), the process proceeds to step S2.

[0048] In step S2, the judgment unit 26 judges whether or not 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 does not occur in the error signal eR (NO in step S2), the process shown in FIG. 7 is completed.

[0049] In step S3, the control unit 28 causes the filter coefficient updating unit 40C to update the filter coefficient W2 in the adaptive filter 36C based on the reference signal r corrected by the acoustic characteristics filter 38C and the error signal eR.

[0050] In step S4, the control unit 28 causes the filter coefficient updating unit 40C to update the filter coefficient W2 in the adaptive filter 36C based on the reference signal r corrected by the acoustic characteristics filter 38C and the error signal eL.

[0051] Thus, the process shown in FIG. 7 is completed.

[0052] In this manner, in this 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 together to obtain the summed error signal eC. The summed error signal eC corresponds to the residual noise at the center in the vehicle width direction. Then, the filter coefficient W2 in the adaptive filter 36C is updated so that the summed error signal eC thus obtained is minimized. According to this embodiment, the residual noise at the center in the vehicle width direction can be appropriately reduced without the need to separately provide a microphone at the center in the vehicle width direction. According to this embodiment, the complexity of the control can be suppressed, and therefore the design cost can be suppressed. In addition, according to this embodiment, the increase in the amount of calculation can be suppressed, and therefore an expensive processor is not required, and the component cost can be suppressed. Therefore, according to this embodiment, it is possible to provide an active noise control device 10 that can effectively reduce noise and achieve low cost.

[0053] [Modified embodiment] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention.

[0054] For example, in the above embodiment, the central actuator 16C is provided, but the central actuator 16C does not have to be provided. In this case, the same control signal may be supplied to the one-side actuator 16L and the other-side actuator 16R. In other words, if a monaural sound is output from the pair of actuators 16L and 16R, the central actuator 16C may not be provided. However, from the viewpoint of reducing noise more effectively, it is preferable that the central actuator 16C is provided.

[0055] The above embodiment can be summarized as follows.

[0056] The active noise control device (10) is an active noise control device that outputs a canceling sound based on a control signal (uC) from an actuator (16C) in order to reduce noise in a passenger compartment (14) of a vehicle (12), and includes: a first adaptive filter (34C) that generates the control signal by performing a filtering process on a reference signal (r) corresponding to the noise; and a first filter coefficient update unit (40C) that updates a filter coefficient (W2) in the first adaptive filter based on a sum error signal (eC) obtained by adding together a first error signal (eL) obtained by detecting residual noise due to interference between the noise and the canceling sound using a first microphone (20L) arranged on one side of the passenger compartment centered on a center line (CL) of the vehicle along the longitudinal direction of the vehicle, and a second error signal (eR) obtained by detecting the residual noise using a second microphone (20R) arranged on the other side of the passenger compartment centered on the center line of the vehicle, and the reference signal. According to this configuration, a first error signal detected by a first microphone arranged on one side and a second error signal detected by a second microphone arranged on the other side are added together to obtain an added error signal corresponding to the residual noise at the center in the vehicle width direction. Then, the filter coefficient in the first adaptive filter is updated so that the added error signal thus obtained is minimized. According to this configuration, the residual noise at the center in the vehicle width direction can be appropriately reduced without the need to separately provide a microphone at the center in the vehicle width direction. According to this configuration, the complexity of the control can be suppressed, and therefore the design cost can be suppressed. Furthermore, according to this configuration, an increase in the amount of calculation can be suppressed, and therefore an expensive processor is not required, and the component cost can be suppressed. Therefore, according to this configuration, it is possible to provide an active noise control device that can effectively reduce noise and achieve low costs.

[0057] The system may further include a first acoustic characteristic filter (38C) that corrects the reference signal by performing filtering processing on the reference signal according to acoustic characteristics (C^20) from the actuator to the first microphone and acoustic characteristics (C^21) from the actuator to the second microphone, and the first filter coefficient update unit may update the filter coefficient in the first adaptive filter based on the added error signal and the reference signal corrected by the first acoustic characteristic filter. With this configuration, the filtering processing according to the acoustic characteristics from the actuator to the pair of microphones is performed by the first acoustic characteristic filter, so that noise can be effectively suppressed while reducing the amount of calculation.

[0058] The system may further include a determination unit (26) that determines whether an abnormality occurs in either the first error signal or the second error signal, and a control unit (28) that, when the determination unit determines that an abnormality occurs in one of the first error signal or the second error signal, causes the first filter coefficient update unit to update the filter coefficient in 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 characteristics filter. With this configuration, even if an abnormality occurs in one of a pair of microphones, it is possible to effectively reduce noise while suppressing adverse effects caused by the microphone having an abnormality.

[0059] The actuator may be provided at a center in a vehicle width direction. According to this configuration, it is possible to provide an active noise control device that can effectively reduce noise inside the vehicle cabin.

[0060] a second adaptive filter (36A) that performs a filtering process on the reference signal that is different from the filtering process performed by the first adaptive filter, thereby generating a control signal (uL) to be supplied to a one-side actuator (16L) arranged on one side of the vehicle interior centered on the center line of the vehicle; a second acoustic characteristic filter (38A1) that corrects the reference signal by performing a filtering process on the reference signal in accordance with an acoustic characteristic (C^00) from the one-side actuator to the first microphone; a second filter coefficient update unit (40A1) that updates a filter coefficient (W0) in the second adaptive filter based on the first error signal and the reference signal corrected by the second acoustic characteristic filter; a third acoustic characteristic filter (38A2) that corrects the reference signal by performing a filtering process on the reference signal in accordance with an acoustic characteristic (C^01) from the one-side actuator to the second microphone; a third filter coefficient update unit (40A2) that updates a filter coefficient of the third adaptive filter, a third adaptive filter (36B) that performs a filtering process on the reference signal that is different from either the filtering process performed by the first adaptive filter or the filtering process performed by the second adaptive filter, thereby generating a control signal (uR) to be supplied to an other-side actuator (16R) arranged on the other side of the vehicle interior centered on the center line of the vehicle, a fourth acoustic characteristic filter (38B1) that corrects the reference signal by performing a filtering process on the reference signal according to an acoustic characteristic (C^10) from the other-side actuator to the first microphone, a fourth filter coefficient update unit (40B1) that updates a filter coefficient (W1) in the third adaptive filter based on the first error signal and the reference signal corrected by the fourth acoustic characteristic filter, and a fifth acoustic characteristic filter (38B2) that corrects the reference signal by performing a filtering process on the reference signal according to an acoustic characteristic (C^11) from the other-side actuator to the second microphone.The control system may further include a fifth filter coefficient update unit (40B2) that updates the filter coefficient in the third adaptive filter based on the second error signal and the reference signal corrected by the fifth acoustic characteristic filter. With this configuration, it is possible to provide an active noise control device that can effectively reduce noise.

[0061] The actuator may include a one-side actuator disposed on one side of the vehicle interior centered on the center line of the vehicle, and a second-side actuator disposed on the other side of the vehicle interior centered on the center line of the vehicle, and the same control signal may be supplied to the one-side actuator and the second-side actuator. With this configuration, it is not necessary to provide an actuator at the center in the vehicle width direction, which contributes to reducing costs.

[0062] The vehicle is equipped with an active noise control device as described above. [Explanation of symbols]

[0063] 10: Active noise control device 12: Vehicle 14: Vehicle interior 15C, 15L, 15R: Power amplifier 16L: One side actuator 16R: Other side actuator 16C: Central actuator 18: Vibration sensor 20L, 20R: Microphone 26: Judgment section 28: Control unit 30: Memory unit 34A to 34C: Filter section 36A to 36C: Adaptive filter 38A1, 38A2, 38B1, 38B2, 38C: Acoustic characteristic filters 40A1, 40A2, 40B1, 40B2, 40C: Filter coefficient update unit 44: Calculation section A~C: Measurement points CL: Center line W0~W2: Filter coefficients eC, eL, eR: Error signals uC, uL, uR: Control signals

Claims

1. An active noise control device that outputs a canceling sound based on a control signal from an actuator in order to reduce noise in a vehicle cabin, a first adaptive filter that generates the control signal by performing a filtering process on a reference signal corresponding to the noise; a first filter coefficient update unit that updates a filter coefficient in the first adaptive filter based on a first error signal obtained by detecting residual noise due to interference between the noise and the canceling sound by a first microphone arranged on one side of the vehicle interior centered on a center line of the vehicle along a longitudinal direction of the vehicle, and a second error signal obtained by detecting the residual noise by a second microphone arranged on the other side of the vehicle interior centered on the center line of the vehicle, and the reference signal; a first acoustic characteristic filter that corrects the reference signal by performing a filtering process on the reference signal according to an acoustic characteristic from the actuator to the first microphone and an acoustic characteristic from the actuator to the second microphone; Equipped with the first filter coefficient update unit updates the filter coefficient in the first adaptive filter based on the added error signal and the reference signal corrected by the first acoustic characteristic filter; a determination unit that determines whether an abnormality occurs in either the first error signal or the second error signal, and a control unit that, when it is determined by the determination unit that an abnormality has occurred in one of the first error signal and the second error signal, causes the first filter coefficient update unit to update the filter coefficient in 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 characteristics filter.

2. 2. The active noise control device according to claim 1, The actuator is provided at the center in the vehicle width direction.

3. 3. The active noise control device according to claim 2, a second adaptive filter that performs a filtering process on the reference signal that is different from the filtering process performed by the first adaptive filter to generate a control signal to be supplied to a one-side actuator that is disposed on the one side of the vehicle interior centered on the center line of the vehicle; a second acoustic characteristic filter that corrects the reference signal by performing a filtering process on the reference signal according to an acoustic characteristic from the one-side actuator to the first microphone; a second filter coefficient update unit that updates a filter coefficient in the second adaptive filter based on the first error signal and the reference signal corrected by the second acoustic characteristic filter; a third acoustic characteristic filter that corrects the reference signal by performing a filtering process on the reference signal according to acoustic characteristics from the one-side actuator to the second microphone; a third filter coefficient update unit that updates the filter coefficient in the second adaptive filter based on the second error signal and the reference signal corrected by the third acoustic characteristics filter; a third adaptive filter that performs a filtering process on the reference signal that is different from both the filtering process performed by the first adaptive filter and the filtering process performed by the second adaptive filter, thereby generating a control signal to be supplied to an other-side actuator that is disposed on the other side of the vehicle interior centered on the center line of the vehicle; a fourth acoustic characteristic filter that corrects the reference signal by performing a filtering process on the reference signal according to acoustic characteristics from the other side actuator to the first microphone; a fourth filter coefficient update unit that updates a filter coefficient in the third adaptive filter based on the first error signal and the reference signal corrected by the fourth acoustic characteristics filter; a fifth acoustic characteristic filter that corrects the reference signal by performing a filtering process on the reference signal according to acoustic characteristics from the other side actuator to the second microphone; and a fifth filter coefficient update unit that updates the filter coefficient in the third adaptive filter based on the second error signal and the reference signal corrected by the fifth acoustic characteristic filter.

4. 2. The active noise control device according to claim 1, the actuators include a one-side actuator disposed on the one side of the vehicle interior with the center line of the vehicle as a center, and a other-side actuator disposed on the other side of the vehicle interior with the center line of the vehicle as a center, An active noise control device, wherein the same control signal is supplied to the one-side actuator and the other-side actuator.

5. A vehicle equipped with an active noise control device according to any one of claims 1 to 4.

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