CN114255728A - Active noise reduction method, vehicle-mounted active noise reduction system and automobile - Google Patents

Active noise reduction method, vehicle-mounted active noise reduction system and automobile Download PDF

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Publication number
CN114255728A
CN114255728A CN202110394874.XA CN202110394874A CN114255728A CN 114255728 A CN114255728 A CN 114255728A CN 202110394874 A CN202110394874 A CN 202110394874A CN 114255728 A CN114255728 A CN 114255728A
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noise reduction
signal
noise
reference signal
frequency information
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刘益帆
徐银海
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Beijing Ancsonic Technology Co ltd
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Beijing Ancsonic Technology Co ltd
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17853—Methods, e.g. algorithms; Devices of the filter
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1781—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
    • G10K11/17821—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
    • G10K11/17823—Reference signals, e.g. ambient acoustic environment
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17879—General system configurations using both a reference signal and an error signal
    • G10K11/17883—General system configurations using both a reference signal and an error signal the reference signal being derived from a machine operating condition, e.g. engine RPM or vehicle speed
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/128—Vehicles
    • G10K2210/1282—Automobiles

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Fittings On The Vehicle Exterior For Carrying Loads, And Devices For Holding Or Mounting Articles (AREA)

Abstract

The application provides an active noise reduction method, a vehicle-mounted active noise reduction system and an automobile, and relates to the technical field of noise reduction. The method comprises the following steps: acquiring frequency information of engine noise of an automobile; calculating to obtain a noise reduction signal according to the frequency information and the filter coefficient; and playing the noise reduction signal through a loudspeaker array, wherein the loudspeaker array is arranged in a cabin of the automobile. According to the active noise reduction method, the vehicle-mounted active noise reduction system and the vehicle, the noise reduction signal is obtained according to the frequency information of the engine in an active noise reduction mode, and the noise reduction sound wave is sent out in the vehicle cabin to offset the noise of the engine, so that the adverse effect of the noise of the engine on a passenger is greatly reduced, and the riding experience of the passenger is improved.

Description

Active noise reduction method, vehicle-mounted active noise reduction system and automobile
Technical Field
The application relates to the technical field of noise reduction, in particular to an active noise reduction method, a vehicle-mounted active noise reduction system and an automobile.
Background
During the driving of the vehicle, the person sitting in the vehicle can feel very noticeable noise. Such noise is composed of various types of noise, for example, wind noise generated by an external air flow, tire noise (also referred to as road noise) generated by friction between a road surface and a tire, structural noise generated by bumping of parts and articles in a vehicle, and engine noise generated when an engine operates, and the like.
The presence of noise has a great adverse effect on the rider's ride experience, wherein engine noise, which is highly correlated with the speed of rotation of the fluid machine, contains significant narrow-band (fundamental and harmonic) components, and is more severe for the rider, and may even cause various physiological discomforts, such as nervous tension, elevated heart rate, headache, etc. Meanwhile, because the engine noise is low-frequency noise, the diffraction capability is strong, and the energy attenuation is reduced, the engine noise is difficult to isolate or absorb in a physical mode.
Therefore, how to effectively reduce the engine noise borne by the passenger to improve the riding experience of the passenger becomes a problem to be solved in the field.
Disclosure of Invention
In order to solve the technical problem, embodiments of the present application provide an active noise reduction method, a vehicle-mounted active noise reduction system, and an automobile, which aim to reduce engine noise in an automobile cabin in an active noise reduction manner, so as to relieve the trouble of the engine noise to a passenger and improve the riding experience of the passenger.
A first aspect of the present application provides an active noise reduction method, including: acquiring frequency information of engine noise of an automobile; calculating to obtain a noise reduction signal according to the frequency information and the filter coefficient; and playing the noise reduction signal through a loudspeaker array, wherein the loudspeaker array is arranged in a cabin of the automobile.
In one embodiment, calculating the noise reduction signal according to the frequency information and the filter coefficient includes: generating a reference signal according to the frequency information; and calculating to obtain a noise reduction signal according to the reference signal and the filter coefficient.
In one embodiment, the reference signal comprises at least one pair of sine reference signal and cosine reference signal having the same frequency, wherein the frequency of each pair of sine reference signal and cosine reference signal is equal to the fundamental frequency or any harmonic frequency in the frequency information, and the filter coefficients comprise at least one pair of sine coefficient and cosine coefficient, wherein each pair of sine coefficient and cosine coefficient respectively corresponds to each pair of sine reference signal and cosine reference signal.
Here, the calculating the noise reduction signal based on the reference signal and the filter coefficient includes: calculating the linear combination of each pair of sine reference signal and cosine reference signal according to at least one pair of sine coefficient and cosine coefficient to obtain at least one combined signal; and superposing at least one combined signal to obtain a noise reduction signal.
In one embodiment, generating a reference signal according to frequency information includes: generating at least one sinusoidal reference signal according to the frequency information; and shifting the phase of at least one sine reference signal by pi/2 to obtain at least one cosine reference signal respectively corresponding to at least one sine reference signal, thereby obtaining at least one pair of sine reference signal and cosine reference signal with the same frequency.
In one embodiment, before calculating the noise reduction signal according to the frequency information and the filter coefficient, the method further includes: collecting a noise signal by at least one microphone, wherein the at least one microphone is arranged in a cabin of the automobile; from the noise signal, filter coefficients are determined.
Further, in one embodiment, determining filter coefficients from the noise signal includes: adjusting the initial filter coefficient according to the noise signal; a. determining an updated noise signal based on the frequency information and the adjusted filter coefficient; b. when the updated noise signal does not meet the preset optimal condition, adjusting the adjusted filter coefficient again; and (c) iteratively executing the steps a and b until the updated noise signal meets the preset optimal condition, and determining the currently adjusted filter coefficient as the filter coefficient.
In one embodiment, obtaining frequency information of engine noise of an automobile comprises: obtaining engine rotating speed information of an automobile; obtaining frequency information based on the engine speed information; or, collecting noise signals through at least one microphone disposed in a cabin of the automobile; from the noise signal, frequency information is determined.
A second aspect of the present application provides a computer device comprising: a processor; a memory including computer instructions stored thereon, which, when executed by the processor, cause the processor to perform the active noise reduction method provided by any embodiment of the first aspect of the present application.
A third aspect of the present application provides a vehicle-mounted active noise reduction system, comprising: a chip, configured to perform the active noise reduction method provided in any embodiment of the first aspect of the present application; the loudspeaker array is arranged in the cabin of the automobile and used for playing the noise reduction signal.
A fourth aspect of the present application provides an automobile comprising the vehicle-mounted active noise reduction system provided by the third aspect of the present application.
According to the active noise reduction method, the vehicle-mounted active noise reduction system and the vehicle, the noise reduction signal is obtained according to the frequency information of the engine in an active noise reduction mode, and the noise reduction sound wave is sent out in the vehicle cabin to offset the noise of the engine, so that the adverse effect of the noise of the engine on a passenger is greatly reduced, and the riding experience of the passenger is improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
In order to make the objects, technical solutions and advantages of the embodiments of the present application more apparent, the embodiments of the present application will be described in further detail below with reference to the accompanying drawings. It is to be understood that the drawings form a part of the specification, illustrate the present application together with embodiments thereof, and are not to be construed as limiting the present application. Unless otherwise indicated, like reference numbers and designations in the drawings generally refer to like steps or components.
Fig. 1 is a schematic diagram illustrating an exemplary active noise reduction system according to an embodiment of the present application.
Fig. 2 is a schematic flow chart illustrating an active noise reduction method according to an embodiment of the present application.
Fig. 3 is a schematic flow chart of an active noise reduction method according to another embodiment of the present application.
Fig. 4 is a schematic flowchart of an active noise reduction method according to another embodiment of the present application.
Fig. 5 is a schematic flowchart of an active noise reduction method according to another embodiment of the present application.
Fig. 6 is a schematic flowchart of an active noise reduction method according to another embodiment of the present application.
Fig. 7 is a schematic flowchart illustrating an active noise reduction method according to another embodiment of the present application.
Fig. 8 is a schematic flowchart of an active noise reduction method according to another embodiment of the present application.
Fig. 9 is a schematic flowchart illustrating a filter coefficient determination process in the active noise reduction method according to the embodiment shown in fig. 8.
Fig. 10 is a flowchart illustrating an exemplary active noise reduction method according to an embodiment of the present application.
Fig. 11 is a schematic view illustrating a vehicle-mounted active noise reduction system according to an embodiment of the present application.
Fig. 12 is a schematic diagram of a computer device according to an embodiment of the present application.
Detailed Description
Exemplary System
Fig. 1 is a schematic diagram illustrating an exemplary active noise reduction system 100 according to an embodiment of the present application. Active noise reduction system 100 includes: a processor 110, a speaker array 120, and a microphone 130.
The processor 110 is configured to obtain frequency information of the engine noise, calculate a noise reduction signal according to the frequency information and the filter coefficient, and transmit the noise reduction signal to the speaker array 120. In particular, the processor 110 may include an acquisition module 111, a signal generator 112, and a filter 113.
Specifically, the acquisition module 111 is used to acquire frequency information of the engine noise. For example, the obtaining module 111 may directly obtain the rotation speed information of the engine from an electronic control system of the automobile and extract the frequency information of the engine noise therefrom. In another embodiment, the obtaining module 111 may also be connected to the microphone 130 to obtain a noise signal, and determine the frequency information of the engine noise by extracting the fundamental frequency noise and the harmonic noise from the noise signal.
The signal generator 112 may generate a reference signal according to the frequency information from the acquisition module 111 and transmit the reference signal to the filter 113; the filter 113 may calculate a noise reduction signal from the reference signal and the filter coefficients and pass the noise reduction signal to the speaker array 120.
The speaker array 120 is used for playing the noise reduction sound wave according to the received noise reduction signal. Specifically, the speaker array 120 may include a plurality of speakers respectively disposed at respective positions in the vehicle compartment. For example, a plurality of speakers may be provided on the front and rear sides of the vehicle compartment, or may be provided near the headrest of each seat, or the like, so that noise reduction sound waves are well propagated in the vehicle compartment. It should be understood that, in the embodiment of the present application, the speaker array 120 may directly use the sound system of the vehicle itself, or may additionally provide speakers according to actual needs, which is not limited in the embodiment of the present application.
The microphone 130 is used to collect noise in the cabin and convert it to a noise signal that is transmitted to other parts of the system as needed.
Preferably, in another embodiment, the processor 110 may further include an adaptation module 114. The adaptation module 114 may be connected to the signal generator 112 and the microphone 130, and configured to receive the reference signal from the signal generator 112 and the noise signal from the microphone 130, and perform an optimal adjustment on the filter coefficient of the filter 113 through an adaptation algorithm according to the reference signal and the noise signal.
In one embodiment, the microphone 130 may start to collect raw noise (i.e., noise without noise reduction processing) in the cabin before the active noise reduction mode is turned on (i.e., the filter 113 has not started to emit the noise reduction signal), and send the raw noise signal to the obtaining module 111, so that the obtaining module 111 extracts frequency information of the engine noise from the raw noise signal.
In another embodiment, the microphone 130 may start to collect noise in the cabin after the active noise reduction mode is turned on. At this time, since the speaker array 120 is already playing the noise reduction sound wave, the noise signal obtained by the microphone 130 is a superposition of the original noise signal and the noise reduction signal, i.e., an error therebetween. After the adaptive module 114 receives the noise signal at this time, the filter coefficient may be optimally adjusted according to the noise signal.
It should be understood that the paths shown by the dashed lines in fig. 1 represent the propagation paths of acoustic signals other than the circuit.
It should be understood that the above active noise reduction system is only an implementation manner of an exemplary system provided in the embodiments of the present application, and the above description is only used to make the technical solutions provided in the embodiments of the present application easier to understand, and is not to be considered as a limitation of the present application.
Exemplary method
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments that can be derived from the embodiments given herein by a person of ordinary skill in the art are intended to be within the scope of the present disclosure.
Fig. 2 is a schematic flow chart illustrating an active noise reduction method according to an embodiment of the present application. The method may be performed, for example, by the processor 110 in the exemplary active noise reduction system 100. As shown in fig. 2, the method includes:
s210: frequency information of engine noise of an automobile is acquired.
As described above, the engine noise is related to the rotational speed of the engine, and is mainly composed of fundamental frequency noise and harmonic frequency noise. That is, the frequencies of fundamental frequency noise and harmonic frequency noise in the engine noise (for example, rpm/60Hz (fundamental frequency), 2rpm/60Hz, 4rpm/60 Hz..) can be determined as long as the rotational speed information of the engine is grasped.
Therefore, as shown in fig. 3, in an embodiment, S210 may specifically include the following steps:
s2111: and acquiring the engine speed information of the automobile.
S2112: based on the engine speed information, frequency information of the engine noise is obtained.
Specifically, the engine speed information may be directly obtained by a vehicle electronic control system (for example, a data bus in a CAN bus or a CAN FD bus of the vehicle), or may be collected by a speed sensor provided in the engine.
In addition, because the engine noise mainly consists of fundamental frequency noise and harmonic frequency noise, and the fundamental frequency noise and the harmonic frequency noise are narrow-band signals, the engine noise is obviously different from other noises and is easy to extract. Therefore, the frequency information of the engine noise can be determined by collecting the noise in the cabin and extracting the fundamental frequency signal and the harmonic frequency signal from the noise. Specifically, as shown in fig. 4, in another embodiment, S210 may include:
s2121: the noise signal is collected by at least one microphone arranged in the cabin of the motor vehicle.
S2122: frequency information of the engine noise is determined based on the noise signal.
At least one microphone may be provided, for example, in the cabin in the vicinity of the seat above, so that the noise picked up is closer to the noise actually heard by the occupant.
Preferably, the at least one microphone may comprise an array of microphones distributed about a plurality of seats in the vehicle cabin. For example, a microphone can be respectively arranged at positions, close to ears of a passenger, of a headrest of each seat or a hand grip above the seat in an inclined manner, so that multiple passengers in the cabin can be considered simultaneously, active noise reduction is achieved more pertinently, and riding experience is improved.
S220: and calculating to obtain a noise reduction signal according to the frequency information and the filter coefficient.
After the filter receives the frequency information of the engine noise, calculation can be carried out based on the filter coefficient, and a noise reduction signal with the phase opposite to that of the engine noise is obtained.
S230: playing the noise reduction signal through the loudspeaker array.
Wherein the loudspeaker array is arranged in a cabin of the automobile. Specifically, the speaker array may include a plurality of speakers respectively provided at respective positions in the vehicle compartment. For example, a plurality of speakers may be provided on the front and rear sides of the vehicle compartment, or may be provided near the headrest of each seat, or the like, so that noise reduction sound waves are well propagated in the vehicle compartment. It should be understood that the speaker array may be a sound system of the vehicle itself, or may be a speaker additionally provided according to actual needs, which is not limited by the embodiment of the present application.
After the speaker array receives the noise reduction signal, the noise reduction sound wave can be played based on the noise reduction signal. The noise reduction sound waves are transmitted in the vehicle cabin and reach spatial points near the seats, and the noise reduction sound waves and the engine noise are offset with each other, so that the engine noise at the spatial points is weakened.
According to the active noise reduction method, the noise reduction signal is obtained according to the frequency information of the engine noise in an active noise reduction mode, and the noise reduction sound wave is sent out in the vehicle cabin to offset the engine noise, so that the adverse effect of the engine noise on a passenger is greatly reduced, and the riding experience of the passenger is improved.
Fig. 5 is a schematic flowchart of an active noise reduction method according to another embodiment of the present application. The method may be performed, for example, by the processor 110 in the exemplary active noise reduction system 100. As shown in fig. 5, S220 in the method shown in fig. 2 may specifically include:
s221: and generating a reference signal according to the frequency information.
S222: and calculating to obtain a noise reduction signal according to the reference signal and the filter coefficient.
After obtaining the frequency information of the engine noise, the processor 110 may generate a reference signal having the same frequency distribution as the engine noise according to the frequency information, so that the filter further calculates a noise reduction signal having the same amplitude and opposite phase to the engine noise according to the reference signal.
For example, in the embodiment shown in fig. 6, the reference signal may include at least one pair of sine reference signal and cosine reference signal having the same frequency, wherein the frequency of each pair of sine reference signal and cosine reference signal is equal to the fundamental frequency or any harmonic frequency in the frequency information.
It can be understood that the distribution of the fundamental frequency signal or the harmonic frequency signal in the frequency domain can be regarded as the frequency domain distribution of a sinusoidal signal, and the sinusoidal signal can be completely restored by obtaining the amplitude and the phase of the corresponding fundamental frequency signal or the corresponding harmonic frequency signal. Based on this, the applicant found that it is possible to set a sine signal and a cosine signal having the same frequency as the fundamental frequency signal or the harmonic frequency signal as reference signals (i.e., a sine reference signal and a cosine reference signal) corresponding to the fundamental frequency signal or the harmonic frequency signal, and to calculate a linear combination of the sine reference signal and the cosine reference signal (i.e., a sine signal having the same frequency domain distribution as the fundamental frequency signal or the harmonic frequency signal) by setting coefficients for the sine reference signal and the cosine reference signal, respectively, and to adjust the coefficients corresponding to the sine reference signal and the cosine reference signal (i.e., to adjust the amplitude and the phase of the linear combination signal) to restore the fundamental frequency signal or the harmonic frequency signal.
Based on this, when the noise reduction signal is calculated for a fundamental frequency signal or any harmonic frequency signal in the engine noise, a sine reference signal and a cosine reference signal may be set for the fundamental frequency signal or the harmonic frequency signal, and coefficients corresponding to the sine reference signal and the cosine reference signal are implemented as filter coefficients, so that the calculated linear combination of the two has the same amplitude and opposite phase as the fundamental frequency signal or the harmonic frequency signal. That is, based on a sine reference signal and a cosine reference signal, and corresponding filter coefficients, a noise reduction signal corresponding to a fundamental frequency signal or a harmonic frequency signal can be calculated.
Thus, in the present embodiment, the filter coefficients may include at least one pair of sine and cosine coefficients. That is, a pair of sine coefficient and cosine coefficient may be set for each fundamental frequency signal or harmonic frequency signal. Each pair of sine coefficient and cosine coefficient respectively corresponds to each pair of sine reference signal and cosine reference signal, and is used for calculating the linear combination of each pair of sine reference signal and cosine reference signal, so as to obtain the noise reduction signal corresponding to each fundamental frequency signal or harmonic frequency signal.
It should be understood that, according to the actual engine noise energy spectrum and the noise reduction requirement, only the fundamental frequency signal in the engine noise may be selected to be subjected to noise reduction, only one/multiple harmonic frequency signals may be selected to be subjected to noise reduction, and multiple signals in the fundamental frequency signal and the harmonic frequency signals may be selected to be subjected to noise reduction at the same time, which is not limited in the embodiment of the present application.
Specifically, as shown in fig. 6, in an embodiment, the step of generating the reference signal according to the frequency information (S221) may include:
s2211: at least one sinusoidal reference signal is generated from the frequency information.
S2212: and shifting the phase of at least one sine reference signal by pi/2 (or odd times of pi/2) to obtain at least one cosine reference signal respectively corresponding to at least one sine reference signal, thereby obtaining at least one pair of sine reference signal and cosine reference signal with the same frequency.
For example, when actively reducing the noise of the fundamental frequency in the engine noise, a sine reference signal having the same frequency as the fundamental frequency noise may be generated first, and then a cosine reference signal having the same frequency as the sine reference signal may be obtained by shifting the phase of the sine reference signal by pi/2 by using the phase relationship characteristic between the sine signal and the cosine signal.
The reference signal generation method provided by the embodiment of the application is simple in principle and easy to implement, and can effectively save computing resources. It should be understood that the reference signal may be generated in other ways, and the embodiments of the present application do not limit this.
In an embodiment, as shown in fig. 7, S222 in the method shown in fig. 5 may specifically include:
s2221: and calculating the linear combination of each pair of sine reference signal and cosine reference signal according to at least one pair of sine coefficient and cosine coefficient to obtain at least one combined signal.
S2222: and superposing at least one combined signal to obtain a noise reduction signal.
In an embodiment, when the noise reduction is selected for simultaneously reducing the plurality of fundamental frequency signals and harmonic frequency signals, after a combined signal (i.e., a noise reduction signal) corresponding to each of the signals is calculated, the plurality of combined signals may be superimposed to obtain a noise reduction signal corresponding to engine noise.
The active noise reduction method provided by the application adopts the reference signal and the filter coefficient to track the amplitude and the phase of the engine noise, is simple to calculate and easy to realize, and provides a smart solution for the prior technical problem. Furthermore, based on the characteristics of the engine noise, active noise reduction is performed by adopting sine and cosine signals which are easy to generate as reference signals, so that the noise reduction effect is ensured, the implementation difficulty and cost of the technical scheme are reduced, and the possibility of technical popularization is improved.
Fig. 8 is a schematic flowchart of an active noise reduction method according to another embodiment of the present application. The method may be performed, for example, by the processor 110 in the exemplary active noise reduction system 100.
As shown in fig. 8, in this embodiment, the active noise reduction method shown in fig. 2 to 7 may further include:
s810: noise signals are collected by at least one microphone.
The microphone is arranged in a cabin of the automobile and used for collecting noise in the cabin and converting the collected noise into a noise signal.
Specifically, in an embodiment of the present application, S2121 and S810 may be performed by the same at least one microphone. That is, the at least one microphone may begin to capture raw noise in the cabin prior to the active noise reduction mode being turned on for the processor to determine frequency information of the engine noise; the noise in the vehicle cabin can be collected continuously after the active noise reduction mode is started.
In this embodiment, since the speaker array has already started playing the noise reduction signal, the noise signal collected by the microphone is the superposition of the original noise signal and the noise reduction signal, i.e. the error between the two.
S820: from the noise signal, filter coefficients are determined.
After the noise signal is acquired by the at least one microphone, the noise signal may be communicated to the processor through the circuitry.
It will be appreciated that after the active noise reduction mode is turned on, the noise reduction signal played by the speaker array is determined by the filter in the processor based on the reference signal and the initial filter coefficients. At this time, since the initial filter coefficient is not debugged online, the current engine noise may not be accurately restored, and an error between the noise reduction signal and the original noise signal may be large.
In view of this, in order to further improve the active noise reduction effect for the engine noise, in the embodiment, after receiving the noise signal, the processor may perform an optimal adjustment on the initial filter coefficient according to the noise signal to determine an (optimal) filter coefficient.
In one embodiment, as shown in fig. 9, S820 may include:
s821: the initial filter coefficients are adjusted based on the noise signal.
S822: an updated noise signal is determined based on the frequency information and the adjusted filter coefficients.
S823: and judging whether the current updated noise signal meets preset optimal conditions, if so, executing S825, and if not, executing S824.
S824: the adjusted filter coefficients are adjusted again, and S822 is executed again.
Before the updated noise signal satisfies the preset optimal condition, steps S822 and S824 may be iteratively performed until the updated noise signal satisfies the preset optimal condition.
S825: and determining the current adjusted filter coefficient as the filter coefficient.
Specifically, when it is determined that the noise signal does not reach the preset optimal condition, the initial filter coefficient may be adjusted, and the updated noise reduction signal may be determined by using the adjusted filter coefficient. After the loudspeaker array plays the updated noise reduction signal, the microphone can acquire the updated noise signal. When the updated noise signal is judged to still not reach the preset optimal condition, the filter coefficient can be adjusted again to obtain the noise signal updated again. And repeating the steps until the noise signal meets the preset optimal condition, stopping adjustment, and determining the current filter coefficient (namely the filter coefficient after the last adjustment) as the final filter coefficient.
In one embodiment, for example, the energy of the noise signal reaching the minimum value may be set as the optimal condition, that is, whether the noise signal satisfies the preset optimal condition is determined by determining whether the energy of the noise signal reaches the minimum value.
Here, the process of repeatedly adjusting the filter coefficients and updating the noise signal may be implemented by using an adaptive algorithm, such as an LMS (Least Mean Square) algorithm, and the filter coefficients are updated each time until the noise signal is optimized. It should be understood that the embodiments of the present application do not limit the algorithm actually used.
In another embodiment of the present application, filter coefficients corresponding to different rotational speeds of the engine may also be predetermined. During the actual running process of the automobile, the processor can confirm the current engine speed (or the frequency information of the engine noise) in real time and directly switch the filter coefficient into the predetermined filter coefficient corresponding to the current engine speed.
It is understood that the rotation speed of the engine may fluctuate when the automobile is actually running, and the landing, movement, and the like of the occupant may change the change of the acoustic path in the cabin. Therefore, preferably, in another embodiment, a predetermined filter coefficient may be called according to the engine speed, and the filter coefficient may be further adjusted through the foregoing adaptive process when the engine speed or the acoustic path in the vehicle cabin changes, so as to further improve the noise reduction effect.
According to the active noise reduction method, the residual noise signals after noise reduction are collected in real time in the driving process of the vehicle, and the filter coefficient is optimized and updated according to the noise signals, so that the active noise reduction effect is greatly improved, and the riding experience is further improved.
FIG. 10 is a flowchart illustrating an exemplary active noise reduction method provided by an embodiment of the present application, which may be executed by processor 110 of active noise reduction system 100 shown in FIG. 1, for actively reducing fundamental frequency noise in engine noise of a vehicle.
As shown in fig. 10, the method may include the steps of:
s1001: and acquiring the engine speed information of the automobile.
S1002: and obtaining the frequency information of the fundamental frequency noise in the engine noise based on the engine rotating speed information.
S1003: and generating a sinusoidal reference signal according to the frequency information of the fundamental frequency noise.
S1004: and shifting the phase of the sine reference signal by pi/2 to obtain a cosine reference signal corresponding to the sine reference signal, thereby obtaining a pair of sine reference signal and cosine reference signal with the same frequency.
S1005: and calculating the linear combination of the sine reference signal and the cosine reference signal according to the initial filter coefficient (comprising a pair of initial sine coefficient and initial cosine coefficient) to obtain an initial noise reduction signal.
S1006: the initial noise reduction signal is played through the speaker array.
S1007: noise signals are collected by a microphone array.
S1008: the initial filter coefficients are adjusted based on the noise signal.
S1009: an updated noise signal is determined based on the sine reference signal, the cosine reference signal and the adjusted filter coefficients.
S1010: and judging whether the currently updated noise signal meets preset optimal conditions, if so, executing S1012, and if not, executing S1011.
S1011: the adjusted filter coefficients are adjusted again, and S1009 is executed again.
S1012: the current adjusted filter coefficients are determined to be filter coefficients (comprising a pair of sine and cosine coefficients).
S1013: and calculating the linear combination of the sine reference signal and the cosine reference signal according to the sine coefficient and the cosine coefficient to obtain a combined signal as a noise reduction signal.
S1014: playing the noise reduction signal through the loudspeaker array.
Specifically, for example, the following pair of sine and cosine signals may be generated as the reference signal:
xs(k)＝Asin(ω0k) formula (1)
xc(k)＝Acos(ω0k) Formula (2)
Wherein, ω is0K is the central frequency of the fundamental frequency noise, and k is the iteration number of the self-adaptive algorithm. Then, the noise reduction signal corresponding to the jth speaker in the speaker array is:
Figure BDA0003018154580000121
wherein, ws，j(k) And wc，j(k) Filter coefficients for the two reference signals, respectively. From the above formula, the amplitude of the noise reduction signal is
Figure BDA0003018154580000122
Phase is
Figure BDA0003018154580000123
In the process of iteratively adjusting the filter coefficients, the updated noise signal vector can be obtained according to each iteration
Figure BDA0003018154580000124
Adjusting ws，j(k) And wc，j(k) Up to
Figure BDA0003018154580000125
Converging to a minimum value. Wherein i is the number of microphones in the microphone array.
After the iterative process is converged, the obtained noise reduction signal reaches each microphone in the microphone array through the corresponding acoustic path, and the noise reduction signal is cancelled with the fundamental frequency noise at the spatial point where each microphone is located, so that active noise reduction is realized.
It should be understood that the method shown in this embodiment is onlyMethod for reducing noise of fundamental frequency noise, and method for reducing noise of harmonic frequency noise (center frequency of 2 omega)0、4ω0、6ω0...) and may be implemented simultaneously therewith, and will not be described in detail herein.
Exemplary devices
An embodiment of the present application further provides an active noise reduction device, which may include: the acquisition module is used for acquiring frequency information of engine noise of the automobile; the calculation module is used for calculating to obtain a noise reduction signal according to the frequency information and the filter coefficient; and the sending module is used for sending the noise reduction signal to the loudspeaker array so as to enable the loudspeaker array to play the noise reduction signal. Wherein the loudspeaker array may be provided in a cabin of the vehicle.
Specifically, the acquisition module can directly acquire the rotating speed information of the engine from an electronic control system of the automobile and extract the frequency information of the engine noise from the rotating speed information; the actually collected noise in the vehicle cabin can also be received, and the frequency information of the engine noise is determined from the noise in the vehicle cabin based on the narrow-frequency characteristic of the engine noise.
In an embodiment, the calculation module may be specifically configured to: generating a reference signal according to the frequency information; and calculating to obtain a noise reduction signal according to the reference signal and the filter coefficient.
In one embodiment, the reference signal may include at least one pair of a sine reference signal and a cosine reference signal having the same frequency. And the frequency of each pair of sine reference signal and cosine reference signal is equal to the fundamental frequency or any harmonic frequency in the frequency information. Meanwhile, the filter coefficients may include at least one pair of sine and cosine coefficients. Wherein each pair of sine coefficient and cosine coefficient respectively corresponds to each pair of sine reference signal and cosine reference signal.
In this embodiment, the calculation module may specifically be configured to: calculating the linear combination of each pair of sine reference signal and cosine reference signal according to at least one pair of sine coefficient and cosine coefficient to obtain at least one combined signal; and superposing at least one combined signal to obtain a noise reduction signal.
In an embodiment, the calculation module may be specifically configured to: generating at least one sinusoidal reference signal according to the frequency information; and shifting the phase of at least one sine reference signal by pi/2 (or odd times of pi/2) to obtain at least one cosine reference signal respectively corresponding to at least one sine reference signal, thereby obtaining at least one pair of sine reference signal and cosine reference signal with the same frequency.
In an embodiment, the calculation module may be further configured to determine the filter coefficient according to the noise signal collected by the at least one microphone. Wherein at least one microphone (which may be a microphone array, for example) may be provided in the cabin of the car for picking up the noise signal.
Specifically, the process of determining the filter coefficients from the noise signal by the calculation module may be implemented based on an adaptive algorithm, and the process may include:
adjusting the initial filter coefficient according to the noise signal;
a. determining an updated noise signal based on the frequency information and the adjusted filter coefficient;
b. when the updated noise signal does not meet the preset optimal condition, adjusting the adjusted filter coefficient again;
and (c) iteratively executing the steps a and b until the updated noise signal meets the preset optimal condition, and determining the currently adjusted filter coefficient as the filter coefficient.
The active noise reduction device provided by the application obtains the noise reduction signal according to the frequency information of the engine noise in an active noise reduction mode, and sends the noise reduction sound wave in the vehicle cabin to offset the engine noise, so that the adverse effect of the engine noise on a passenger is greatly reduced, and the riding experience of the passenger is improved.
It should be understood that the principles, functions, and technical effects of the components in the active noise reduction apparatus provided in the foregoing embodiments may refer to corresponding contents in the exemplary method, and are not described in detail herein.
Fig. 11 is a schematic diagram of a vehicle active noise reduction system 1100 according to an embodiment of the present disclosure. As shown in fig. 11, the in-vehicle active noise reduction system 1100 includes a chip 1110 and a speaker array 1120.
The chip 1110 may be configured to perform the active noise reduction method provided in any of the above embodiments; the speaker array 1120 may be disposed in a cabin of an automobile for playing the noise reduction signal.
The vehicle-mounted active noise reduction system provided by the application obtains the noise reduction signal according to the frequency information of the engine noise in an active noise reduction mode, and sends the noise reduction sound wave in the vehicle cabin to offset the engine noise, so that the adverse effect of the engine noise on a passenger is greatly reduced, and the riding experience of the passenger is improved.
Exemplary device
An embodiment of the present application further provides an automobile, which includes the aforementioned vehicle-mounted active noise reduction system 1100. During the driving period of the automobile, the vehicle-mounted active noise reduction system can actively reduce the noise of the engine, improve the riding environment of a passenger and improve the riding experience.
Fig. 12 is a schematic diagram of a computer device according to an embodiment of the present application. As shown in fig. 12, the computer apparatus includes: a processor 1210; memory 1220, memory 1220 including computer instructions stored thereon, which when executed by processor 1210, cause processor 1210 to perform an active noise reduction method as provided in any of the embodiments described above.
Exemplary computer readable storage Medium
Other embodiments of the present application further provide a computer-readable storage medium having stored thereon a computer program which, when executed by a processor, implements the active noise reduction method according to any of the above embodiments. It is understood that the computer storage medium can be any tangible medium, such as: floppy disks, CD-ROMs, DVDs, hard drives, network media, or the like.
The block diagrams of apparatuses, devices, systems referred to in this application are only given as illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. Those skilled in the art will appreciate that the devices, apparatus, systems, etc. may be connected, arranged, or configured in any manner. Words such as "comprising," "including," "having," and the like are open-ended words to "including, but not limited to," and may be used interchangeably therewith unless the context clearly dictates otherwise. The word "such as" is used herein to mean, and is used interchangeably with, the phrase "such as but not limited to".
It should also be noted that in the devices, apparatuses, and methods of the present application, the modules or steps may be decomposed and/or recombined. These decompositions and/or recombinations are to be considered as equivalents of the present application.
The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the above aspects but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The above description is intended to be illustrative and descriptive of the present technology. Furthermore, the description is not intended to limit embodiments of the application to the form disclosed above. While a number of exemplary aspects and embodiments have been discussed above, other variations, modifications, changes, additions, and sub-combinations will readily occur to those skilled in the art based upon the foregoing.
The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modifications, equivalents and the like that are within the spirit and principle of the present application should be included in the scope of the present application.

Claims (10)

1. An active noise reduction method, comprising:
acquiring frequency information of engine noise of an automobile;
calculating to obtain a noise reduction signal according to the frequency information and the filter coefficient;
and playing the noise reduction signal through a loudspeaker array, wherein the loudspeaker array is arranged in the cabin of the automobile.
2. The active noise reduction method of claim 1, wherein calculating a noise reduction signal according to the frequency information and filter coefficients comprises:
generating a reference signal according to the frequency information;
and calculating to obtain the noise reduction signal according to the reference signal and the filter coefficient.
3. The active noise reduction method of claim 2, wherein:
the reference signal comprises at least one pair of sine reference signal and cosine reference signal with the same frequency, wherein the frequency of each pair of sine reference signal and cosine reference signal is equal to the fundamental frequency or any harmonic frequency in the frequency information,
the filter coefficients comprise at least one pair of sine and cosine coefficients, wherein each pair of sine and cosine coefficients corresponds to the pair of sine and cosine reference signals, respectively,
wherein, according to the reference signal and the filter coefficient, calculating the noise reduction signal includes:
calculating the linear combination of each pair of sine reference signal and cosine reference signal according to the at least one pair of sine coefficient and cosine coefficient to obtain at least one combined signal;
and superposing the at least one combined signal to obtain the noise reduction signal.
4. The active noise reduction method of claim 3, wherein generating a reference signal according to the frequency information comprises:
generating at least one sinusoidal reference signal according to the frequency information;
and shifting the phase of the at least one sine reference signal by pi/2 to obtain at least one cosine reference signal respectively corresponding to the at least one sine reference signal, thereby obtaining the at least one pair of sine reference signal and cosine reference signal with the same frequency.
5. The active noise reduction method according to any of claims 1-4, further comprising, before calculating a noise reduction signal based on the frequency information and filter coefficients:
collecting a noise signal by at least one microphone, wherein the at least one microphone is disposed in a cabin of the automobile;
determining the filter coefficients from the noise signal.
6. The active noise reduction method of claim 5, wherein determining the filter coefficients from the noise signal comprises:
adjusting an initial filter coefficient according to the noise signal;
a. determining an updated noise signal based on the frequency information and the adjusted filter coefficient;
b. when the updated noise signal does not meet the preset optimal condition, adjusting the adjusted filter coefficient again;
and a, iteratively executing the steps a and b until the updated noise signal meets the preset optimal condition, and determining the currently adjusted filter coefficient as the filter coefficient.
7. The active noise reduction method according to any of claims 1-4, wherein obtaining frequency information of engine noise of the automobile comprises:
obtaining engine speed information of the automobile; obtaining the frequency information based on the engine speed information;
alternatively, the first and second electrodes may be,
collecting a noise signal by at least one microphone disposed in a cabin of the automobile; determining the frequency information based on the noise signal.
8. A computer device, comprising:
a processor;
a memory including computer instructions stored thereon that, when executed by the processor, cause the processor to perform the active noise reduction method of any of claims 1-7.
9. An on-vehicle active noise reduction system, comprising:
a chip for performing the active noise reduction method of any one of claims 1-7;
and the loudspeaker array is arranged in the cabin of the automobile and used for playing the noise reduction signal.
10. An automobile comprising the on-board active noise reduction system of claim 9.
CN202110394874.XA 2021-04-13 2021-04-13 Active noise reduction method, vehicle-mounted active noise reduction system and automobile Pending CN114255728A (en)

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