CN114255725A

CN114255725A - Active noise reduction method, vehicle-mounted active noise reduction system and automobile

Info

Publication number: CN114255725A
Application number: CN202110393898.3A
Authority: CN
Inventors: 徐银海; 刘益帆
Original assignee: Beijing Ancsonic Technology Co ltd
Current assignee: Beijing Ancsonic Technology Co ltd
Priority date: 2021-04-13
Filing date: 2021-04-13
Publication date: 2022-03-29

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 a vehicle body vibration signal of an automobile; collecting a noise signal by at least one microphone arranged in a cabin of an automobile; determining a basis coefficient of a space point based on a cabin sound field basis and a noise signal corresponding to the space point where at least one microphone is located; determining filter coefficients according to the base coefficients; calculating to obtain a noise reduction signal according to the vehicle body vibration signal and the filter coefficient; and playing the noise reduction signal through a loudspeaker array arranged in the cabin of the automobile. According to the active noise reduction method, the vehicle-mounted active noise reduction system and the vehicle, noise reduction signals are generated according to vibration information of a vehicle body in an active noise reduction mode, noise reduction sound waves are emitted in a vehicle cabin to offset tire noise, therefore, adverse effects of the tire noise on a passenger are effectively reduced, and 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, such as tire noise (also called road noise), wind noise, and engine noise. The tire noise is composed of air noise at tire pattern gaps/tire bodies, pattern/tire body vibration noise, uneven road noise and the like, and is various in mechanism and complex in frequency component.

The presence of noise has a significant adverse effect on the ride experience of the occupant, and various solutions have been proposed in the prior art for reducing noise. In order to reduce the tire noise, most conventional automobile manufacturers adopt means such as increasing the rigidity of the automobile body, applying sound insulation materials, adding damping cushions and using high-performance silent tires, however, the means are high in implementation cost and have a limited effect of suppressing the tire noise.

Therefore, how to effectively suppress the tire noise to improve the riding experience of the passengers becomes a problem to be solved urgently 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 eliminate a tire noise entering a cabin in an active noise reduction manner, thereby effectively reducing an influence of the tire noise on a passenger and improving a riding experience of the passenger.

A first aspect of the present application provides an active noise reduction method, including: acquiring a vehicle body vibration signal of an automobile; collecting a noise signal by at least one microphone, wherein the at least one microphone is arranged in a cabin of the automobile; determining a basis coefficient of a space point based on a cabin sound field basis and a noise signal corresponding to the space point where at least one microphone is located; determining filter coefficients according to the base coefficients; calculating to obtain a noise reduction signal according to the vehicle body vibration signal 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, determining filter coefficients from the base coefficients comprises: adjusting the initial filter coefficient according to the base coefficient; a. determining an updated noise signal based on the vehicle body vibration signal and the adjusted filter coefficient; b. determining an updated basis coefficient based on the updated noise signal; c. when the updated base coefficient does not meet the preset optimal condition, adjusting the adjusted filter coefficient again; and (c) iteratively executing the steps a, b and c until the updated base coefficient meets the preset optimal condition, and determining the currently adjusted filter coefficient as the filter coefficient.

In an embodiment, iteratively executing steps a, b, and c until the updated basis coefficients satisfy a preset optimal condition, and determining the currently adjusted filter coefficients as the filter coefficients includes: after the ith iteration executes the steps a, b and c, obtaining a base coefficient after 1 time of updating, a base coefficient after 2 times of updating, …, a base coefficient after i-1 times of updating and a base coefficient after i times of updating; judging whether the base coefficient after i times of updating reaches the minimum or not according to the base coefficient after 1 time of updating, the base coefficient after 2 times of updating, …, the base coefficient after i-1 times of updating and the base coefficient after i times of updating; and when the base coefficient after i times of updating is determined to be the minimum, determining the current adjusted filter coefficient as the filter coefficient.

In one embodiment, the at least one microphone includes a plurality of microphones each positioned adjacent to at least one seat within the cabin.

Further, in an embodiment, the method further comprises: judging the current road condition of the automobile according to the automobile body vibration signal; and switching the filter coefficient to a preset filter coefficient corresponding to the current road condition.

In one embodiment, the cabin sound field basis corresponding to the spatial point of the at least one microphone is determined according to a wave equation, an inner wall boundary function of the cabin of the automobile, and coordinates of the spatial point of the at least one microphone.

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 computer-readable storage medium comprising computer instructions stored thereon, which, when executed by a processor, cause the processor to perform the active noise reduction method provided by any of the embodiments of the first aspect of the present application.

A fourth aspect of the present application provides a vehicle-mounted active noise reduction system, comprising: the vibration sensor is used for acquiring a vehicle body vibration signal of the automobile; the microphone is arranged in a cabin of the automobile and used for acquiring noise signals; 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 fifth aspect of the present application provides an automobile comprising the vehicle-mounted active noise reduction system provided by the fourth aspect of the present application.

According to the active noise reduction method, the vehicle-mounted active noise reduction system and the vehicle, noise reduction signals are generated according to vibration information of a vehicle body in an active noise reduction mode, noise reduction sound waves are emitted in a vehicle cabin to offset tire noise, therefore, adverse effects of the tire noise on a passenger are effectively reduced, and 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 illustrating a process of determining filter coefficients in the active noise reduction method according to the embodiment shown in fig. 2.

Fig. 4 is a schematic flowchart illustrating a process of determining filter coefficients by using an adaptive algorithm in an active noise reduction method according to an 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 diagram of a vehicle-mounted active noise reduction system according to an embodiment of the present application.

Fig. 7 is a schematic diagram of a computer device according to an embodiment of the present application.

Detailed Description

Application scenario overview

As mentioned above, during the driving process of the automobile, the tire noise can be transmitted into the cabin to pollute the riding environment, and cause great trouble to the passengers.

For solving the problem, the method of actively reducing noise is adopted, noise reduction signals aiming at tire noise are generated according to vibration information of a vehicle body, noise reduction sound waves are actively sent out in a vehicle cabin, the tire noise transmitted into the vehicle cabin can be effectively offset, a good riding environment is provided for a rider, and riding experience is improved.

In addition, in the active noise reduction process, it is usually necessary to collect noise through a sensor such as a microphone. However, the microphone may also lose a part of information, such as propagation relationship between different angles and different positions, while collecting information such as intensity and frequency of sound. Particularly, in an uneven sound field (such as an automobile cabin), mutual influence necessarily exists among all space points, and information acquired by a microphone cannot be accurately reflected, so that the overall appearance of the sound field cannot be accurately restored.

In order to solve the problem, according to the sound signals collected by the microphones at each space point in the sound field and the multi-order modes corresponding to each space point, a processing mode of single dimension (microphone observation) is converted into a processing mode of double dimensions (microphone observation and sound field mode decomposition), and a part of information lost by the microphones is "retrieved", so that the sound field overall appearance is restored more accurately, and the precision of an active noise reduction algorithm is improved.

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 vibration sensor 110, a processor 120, a speaker array 130, and a microphone 140.

The vibration sensor 110 is used to collect a vibration signal of a body of the automobile. For example, the vibration sensor 110 may be an acceleration sensor mounted on a suspension system of each tire of the automobile or on both front and rear sides of a wheel well near a chassis of the automobile, and the like, and configured to detect vibration information of each tire and suspension to generate a vehicle body vibration signal.

The processor 120 is configured to obtain a vehicle body vibration signal, calculate a noise reduction signal according to the vehicle body vibration signal and the filter coefficient, and transmit the noise reduction signal to the speaker array 130. In particular, the processor 120 may include an acquisition module 121, a filter 122, an adaptation module 123, and a calculation module 124.

Specifically, the obtaining module 121 may be in communication connection with the vibration sensor 110, and is configured to obtain a vehicle body vibration signal from the vibration sensor 110 and transmit the vehicle body vibration signal to the filter 122; the filter 122 may calculate a noise reduction signal from the vehicle body vibration signal and the filter coefficient, and transmit the noise reduction signal to the speaker array 130.

The adaptive module 123 is configured to determine a filter coefficient, and may be connected to the obtaining module 121 and the calculating module 124, and configured to receive the vehicle body vibration signal from the obtaining module and the base coefficient corresponding to the cabin sound field from the calculating module 124, and perform an optimal adjustment on the filter coefficient of the filter 122 through an adaptive algorithm according to the vehicle body vibration signal and the base coefficient.

The calculating module 124 may be connected between the microphone 140 and the adaptive module 123, and configured to determine a basis coefficient of a spatial point according to the cabin sound field basis and the noise signal corresponding to the spatial point where the microphone 140 is located, and transmit the basis coefficient to the adaptive module 123.

The speaker array 130 is used for playing the noise reduction sound wave according to the received noise reduction signal. Specifically, the speaker array 130 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 130 may directly use the vehicle-mounted sound system, or may additionally provide speakers according to actual needs, which is not limited in the embodiment of the present application.

The microphone 140 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.

Wherein, after the active noise reduction mode is turned on, since the speaker array 130 is already playing the noise reduction sound wave, the noise signal obtained by the microphone 140 is the superposition of the original noise signal (i.e. the tire noise without noise reduction processing in the vehicle cabin) and the noise reduction signal, i.e. the error between the two. After receiving the noise signal, the calculating module 124 determines the basis coefficient of the space point according to the cabin sound field basis and the noise signal corresponding to the space point where the microphone 140 is located, and transmits the basis coefficient to the adaptive module 123, so that the adaptive module 123 optimizes and adjusts the filter coefficient through an adaptive algorithm.

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 processor 120 in exemplary active noise reduction system 100. As shown in fig. 2, the method includes:

s210: and acquiring a vehicle body vibration signal of the automobile.

In one embodiment, the vehicle may be provided with a vibration sensor for acquiring a vehicle body vibration signal, for example, an acceleration sensor may be provided at a position near a vehicle chassis on the front and rear sides of a wheel house or a suspension system of a tire, so as to acquire an acceleration signal as a vehicle body vibration signal.

Preferably, in an embodiment, a plurality of vibration sensors may be provided on the vehicle for acquiring a vehicle body vibration signal corresponding to at least one tire. Wherein, a plurality of vibration sensors can be respectively arranged at the position which is near at least one tire and is easy to collect vibration signals. For example, it may be provided on at least one wheel hub of the vehicle, or on the suspension system of the vehicle, or on the frame in the vicinity of at least one wheel hub.

Here, one vibration sensor may be provided near each tire, a plurality of vibration sensors may be provided near each tire, and a specific arrangement manner may be determined according to actual requirements, which is not limited in the embodiments of the present application.

S220: noise signals are collected by at least one microphone.

Wherein at least one microphone is arranged in the cabin of the automobile. For example, at least one microphone may be provided in the cabin near above the seat 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 may be respectively disposed at positions where the head rest of each seat or the hand grip obliquely above the seat is closer to the ears of the occupants, so as to consider multiple occupants in the cabin at the same time, and implement active noise reduction more specifically, thereby improving riding experience.

S230: and determining the basis coefficient of the space point based on the cabin sound field basis and the noise signal corresponding to the space point where the at least one microphone is located.

It should be understood that the present embodiment expresses the noise signal of the observation point by using the sound field basis (sound field modal decomposition) and the basis coefficient. In this embodiment, the cabin acoustic field basis is predetermined, and therefore, based on the noise signal and the cabin acoustic field basis at the spatial point where the microphone is located, the corresponding basis coefficient can be directly determined. In addition, the optimal condition for the noise signal may be set to a condition that the base coefficient reaches the expected value, and whether or not to stop adjusting the filter may be determined by paying attention to whether or not the corresponding base coefficient reaches the expected value. In this way, it is equivalent to extending the low-dimensional noise measurement information to the high-dimensional information, and compared with the embodiment that only focuses on the noise signal collected by the machine, the present embodiment can restore more sound field information according to the acoustic theory, and further obtain a filter with better noise reduction effect.

Specifically, when the number of the microphones is i, the error signal collected in the vehicle cabin (i.e., the noise signal remaining after noise reduction) can be represented by a vector as

Wherein each frequency component is

(corresponding to frequency f_m) Where T is a transposition operation, M is 1, 2, 3.

The sound field base of the space point of each microphone in the vehicle cabin is a vector and can be used

And (4) showing. Here, the sound field basis may be predetermined based on the wave equation, the boundary function of the inner wall of the cabin of the automobile, and the coordinates of the spatial point where the microphone is located. When the number of the microphones is i, a matrix formed by sound field basis vectors corresponding to the i microphones is a cabin sound field basis (matrix).

The error signal is expressed by the base and the base coefficient of the sound field of the vehicle cabin, and the following are provided:

wherein the content of the first and second substances,

is a sound field base matrix (corresponding frequency f) of an automobile cabin_m) I-th vector in the matrix

I.e. the cabin sound field base (vector) corresponding to the spatial point where the ith microphone is located, and the element phi in the vector_i，N(f_m) The Nth order sound field substrate of the space point is obtained;

is a sound field base coefficient vector (corresponding to a frequency f) of an automobile cabin_m)。

As can be seen from the above equation, after the error signal corresponding to each frequency in the noise signal is determined, the sound field basis coefficient vector can be obtained by the following equation based on the sound field basis matrix set in advance

Wherein psi_D，N×i ^-1(f_m) For cabin sound field base matrix psi_i×N(f_m) The generalized inverse matrix of (2).

It should be noted that the number i of the microphones arranged in the cabin sound field is smaller than the order N of modal decomposition of the cabin sound field, that is, the i-dimensional column vector is obtained by the cabin sound field basis matrix

Conversion to N-dimensional column vectors

(e.g., only 4 microphones are placed in the cabin, and the cabin sound field is finally decomposed into 12 th order), and the low-dimensional noise measurement information is extended to high-dimensional information. Compared with the active noise reduction based on the noise signal acquired by the microphone, the method and the device can restore the complex sound field information to represent the real noise distribution of the space to be subjected to noise reduction, and further can improve the precision of the three-dimensional active noise reduction algorithm.

It should be understood that the sound field basis vector corresponding to each microphone may be determined by a plurality of different basis functions such as sound radiation mode, cavity mode, multipole, etc., and those skilled in the art may select a specific basis function type and modal order according to the usage scenario.

S240: from the base coefficients, filter coefficients are determined.

After the active noise reduction mode is turned on, the noise reduction signal played by the speaker array is determined by a filter in the processor based on the initial filter coefficients. However, in the actual running process of the automobile, the vibration signal of the automobile body may fluctuate at any time; meanwhile, the acoustic path in the vehicle cabin is likely to change due to the seating position, movement, and the like of the occupant. In this case, since the initial filter coefficients are not on-line debugged, the above change cannot be accommodated, and an error between the noise reduction signal and the original noise signal may be large.

In view of this, in order to improve the active noise reduction effect, in the present embodiment, after determining the base coefficients corresponding to the noise signal, the processor may perform an optimal adjustment on the initial filter coefficients according to the base coefficients to determine (optimal) filter coefficients.

In an embodiment, as shown in fig. 3, the process of determining the filter coefficients according to the base coefficients may specifically include the following steps:

s241: the initial filter coefficients are adjusted based on the base coefficients.

S242: and determining an updated noise signal based on the vehicle body vibration signal and the adjusted filter coefficient.

S243: and determining an updated basis coefficient based on the cabin acoustic field basis and the updated noise signal.

S244: judging whether the updated base coefficients meet preset optimal conditions or not; s245 is performed when the updated base coefficients do not satisfy the preset optimum condition, and S246 is performed when the updated base coefficients satisfy the preset optimum condition.

S245: the adjusted filter coefficients are adjusted, and S242 is executed again.

Before the updated base coefficients reach the preset optimal condition, steps S242 (hereinafter referred to as a), S243 (hereinafter referred to as b), and S245 (hereinafter referred to as c) may be iteratively performed until the base coefficients satisfy the preset optimal condition.

S246: the currently adjusted filter coefficients are determined to be (optimal) filter coefficients.

In one embodiment, whether the base coefficients satisfy the predetermined optimal condition may be determined by setting an objective function. For example, let the objective function:

wherein E represents expectation.

That is, in the present embodiment, the error signal vector corresponding to each frequency in the updated noise signal obtained by adjusting the filter each time can be used

Computing updated sound field basis coefficient vectors

And according to

And adjusting the filter coefficients again until the target function J reaches the optimum, namely when the energy of the noise signal described by the sound field base coefficient is minimized, determining the corresponding filter coefficients as final filter coefficients.

Here, the process of iteratively performing steps a, b, and c until the updated basis coefficients satisfy the preset optimal condition may be implemented by using an adaptive algorithm, such as an LMS (Least Mean Square) algorithm. Specifically, as shown in fig. 4, in an embodiment, the process may include:

s410: and after the ith iteration executes the steps a, b and c, obtaining the base coefficient after 1 time of updating, the base coefficient after 2 times of updating, …, the base coefficient after i-1 times of updating and the base coefficient after i times of updating.

S420: and judging whether the base coefficient after i times of updating reaches the minimum or not according to the base coefficient after 1 time of updating, the base coefficient after 2 times of updating, …, the base coefficient after i-1 times of updating and the base coefficient after i times of updating.

S430: and when the base coefficient after i times of updating is determined to be the minimum, determining the current adjusted filter coefficient as the filter coefficient.

In particular, in the ith iteration, the sum of squares of the 2-norms of the basis coefficients (vectors) may be determined according to the above objective function

Whether or not to converge to a minimum value. If the judgment result is yes, the iteration is ended; and if the judgment result is negative, entering the (i +1) th iteration.

After determining the filter coefficients, the active noise reduction method provided by the embodiment shown in fig. 2 further includes:

s250: and calculating to obtain a noise reduction signal according to the vehicle body vibration signal and the filter coefficient.

After the processor 120 receives the body vibration signal, the filter therein may perform a calculation based on the body vibration signal and the filter coefficient to obtain a noise reduction signal for canceling the tire noise (entering the vehicle cabin).

It should be understood that the tire noise transmitted into the vehicle cabin includes a plurality of component noises, but at the root of this, the tire noise is highly correlated with the vehicle body vibration. Therefore, by setting an appropriate filter coefficient after the vehicle body vibration signal is grasped, the tire noise can be "tracked" in the sound field, and a noise reduction signal corresponding to the tire noise can be generated.

S260: playing the noise reduction signal through the loudspeaker array.

Wherein the loudspeaker array is arranged in a cabin of the automobile.

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 tire noise are mutually offset so as to weaken the tire noise at the spatial points.

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.

According to the active noise reduction method, noise reduction signals are generated according to vibration information of the vehicle body in an active noise reduction mode, and noise reduction sound waves are emitted in the vehicle cabin to offset the tire noise, so that the adverse effect of the tire noise on a passenger is effectively reduced, and the riding experience of the passenger is improved; meanwhile, the active noise reduction method provided by the application utilizes the cabin sound field basis to obtain the multi-order mode corresponding to the noise signal, and reconstructs the information lost by the microphone, so that the sound field overall appearance in the cabin can be more accurately restored, the precision of an active noise reduction algorithm is improved, and a better noise reduction effect is realized.

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 processor 120 in exemplary active noise reduction system 100. As shown in fig. 5, the method may further include, on the basis of the method shown in fig. 2:

s510: and judging the current road condition of the automobile according to the vibration signal of the automobile body.

S520: and switching the filter coefficient to a preset filter coefficient corresponding to the current road condition.

Specifically, in this embodiment, before the vehicle enters the driving process, the optimal filter coefficients corresponding to different road conditions may be determined in advance according to typical road conditions, and stored in the storage medium that can be called by the processor 120.

In the actual driving process of the automobile, after the vehicle body vibration signal is acquired, the processor 120 may determine the current vehicle body vibration condition in real time, so as to determine the current road condition of the vehicle. If the predetermined road condition includes the current road condition, the processor 120 may directly switch the filter coefficient to the filter coefficient corresponding to the current road condition.

Further, when the vehicle body vibration signal fluctuates or the acoustic path in the vehicle cabin changes, the processor 120 may further debug the filter coefficient through the foregoing adaptive process, so as to further improve the noise reduction effect.

According to the active noise reduction method, the optimal filter coefficients corresponding to different road conditions are predetermined, and optimization updating is carried out in real time on the basis, so that the debugging time of the filter is greatly reduced, the computing resources are saved, the active noise reduction effect is more quickly presented, and the riding experience is further improved.

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 a vehicle body vibration signal of the automobile; the receiving module is used for receiving noise signals collected by at least one microphone, wherein the at least one microphone is arranged in a cabin of an automobile; the first calculation module is used for determining a base coefficient of a space point based on a cabin sound field base and a noise signal corresponding to the space point where at least one microphone is located, and determining a filter coefficient according to the base coefficient; the second calculation module is used for calculating to obtain a noise reduction signal according to the vehicle body vibration signal 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 is arranged in the cabin of the automobile.

The cabin sound field basis corresponding to the spatial point of the at least one microphone is determined from the wave equation, the boundary function of the inner wall of the cabin of the vehicle and the coordinates of the spatial point of the at least one microphone.

Preferably, the at least one microphone may comprise a plurality of microphones, each of the plurality of microphones being located adjacent to at least one seat within the cabin.

In an embodiment, the first calculation module may specifically be configured to: adjusting the initial filter coefficient according to the base coefficient; a. determining an updated noise signal based on the vehicle body vibration signal and the adjusted filter coefficient; b. determining an updated basis coefficient based on the updated noise signal; c. when the updated base coefficient does not meet the preset optimal condition, adjusting the adjusted filter coefficient again; and (c) iteratively executing the steps a, b and c until the updated base coefficient meets the preset optimal condition, and determining the currently adjusted filter coefficient as the filter coefficient.

The specific process of determining the filter coefficient by the first calculation module may include: after the ith iteration executes the steps a, b and c, obtaining a base coefficient after 1 time of updating, a base coefficient after 2 times of updating, …, a base coefficient after i-1 times of updating and a base coefficient after i times of updating; judging whether the base coefficient after i times of updating reaches the minimum or not according to the base coefficient after 1 time of updating, the base coefficient after 2 times of updating, …, the base coefficient after i-1 times of updating and the base coefficient after i times of updating; and when the base coefficient after i times of updating is determined to be the minimum, determining the current adjusted filter coefficient as the filter coefficient.

In an embodiment, the active noise reduction apparatus may further include a determining module, configured to determine a current road condition of the vehicle according to the vehicle body vibration signal, and switch the filter coefficient to a preset filter coefficient corresponding to the current road condition.

According to the active noise reduction device, noise reduction signals are generated according to vibration information of a vehicle body in an active noise reduction mode, and noise reduction sound waves are emitted in the vehicle cabin to offset tire noise, so that adverse effects of the tire noise on a passenger are effectively reduced, and riding experience of the passenger is improved; meanwhile, the active noise reduction device provided by the application utilizes a multi-order mode corresponding to the noise signal obtained by the cabin sound field base to reconstruct the lost information of the microphone, so that the sound field overall appearance in the cabin can be more accurately restored, the precision of an active noise reduction algorithm is improved, and a better noise reduction effect is realized.

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. 6 is a schematic diagram illustrating a vehicle-mounted active noise reduction system 600 according to an embodiment of the present application. As shown in fig. 6, in-vehicle active noise reduction system 600 includes a vibration sensor 610, a chip 620, at least one microphone 630, and a speaker array 640.

The vibration sensor 610 may be configured to collect a body vibration signal of the vehicle; chip 620 may be used to perform an active noise reduction method as provided in any of the embodiments described above; at least one microphone 630 is disposed in the cabin of the automobile and may be used to collect noise signals; the speaker array 640 may be disposed in a cabin of an automobile for playing the noise reduction signal.

According to the vehicle-mounted active noise reduction system, the noise reduction signal is generated according to the vibration information of the vehicle body in an active noise reduction mode, and the noise reduction sound wave is emitted in the vehicle cabin to offset the tire noise, so that the adverse effect of the tire noise on a passenger is effectively reduced, and the riding experience of the passenger is improved; meanwhile, the active noise reduction device provided by the application utilizes a multi-order mode corresponding to the noise signal obtained by the cabin sound field base to reconstruct the lost information of the microphone, so that the sound field overall appearance in the cabin can be more accurately restored, the precision of an active noise reduction algorithm is improved, and a better noise reduction effect is realized.

Exemplary device

An embodiment of the present application further provides an automobile, which includes the aforementioned vehicle-mounted active noise reduction system 600. During the driving period of the automobile, the vehicle-mounted active noise reduction system can actively reduce the noise of the tire noise entering the automobile cabin, improve the riding environment of a passenger and improve riding experience.

Fig. 7 is a schematic diagram of a computer device according to an embodiment of the present application. As shown in fig. 7, the computer apparatus includes: a processor 710; memory 720, memory 720 including computer instructions stored thereon, which when executed by processor 710, cause processor 710 to perform an active noise reduction method as provided by 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

1. An active noise reduction method, comprising:

acquiring a vehicle body vibration signal of an automobile;

collecting a noise signal by at least one microphone, wherein the at least one microphone is disposed in a cabin of the automobile;

determining a basis coefficient of the space point based on a cabin sound field basis corresponding to the space point where the at least one microphone is located and the noise signal;

determining filter coefficients according to the base coefficients;

calculating to obtain a noise reduction signal according to the vehicle body vibration signal 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 determining filter coefficients from the base coefficients comprises:

adjusting the initial filter coefficient according to the base coefficient;

a. determining an updated noise signal based on the vehicle body vibration signal and the adjusted filter coefficient;

b. determining an updated basis coefficient based on the updated noise signal;

c. when the updated base coefficient does not meet the preset optimal condition, adjusting the adjusted filter coefficient again;

and a, iteratively executing the steps a, b and c until the updated base coefficient meets the preset optimal condition, and determining the current adjusted filter coefficient as the filter coefficient.

3. The active noise reduction method according to claim 2, wherein the iteratively executing steps a, b, and c until the updated basis coefficients satisfy the preset optimal condition, and determining the currently adjusted filter coefficients as the filter coefficients comprises:

after the ith iteration executes the steps a, b and c, obtaining a base coefficient after 1 time of updating, a base coefficient after 2 times of updating, …, a base coefficient after i-1 times of updating and a base coefficient after i times of updating;

judging whether the base coefficient after i times of updating reaches the minimum or not according to the base coefficient after 1 time of updating, the base coefficient after 2 times of updating, …, the base coefficient after i-1 times of updating and the base coefficient after i times of updating;

and when the base coefficient after i times of updating is determined to be the minimum, determining the current adjusted filter coefficient as the filter coefficient.

4. The active noise reduction method of claim 1,

the at least one microphone includes a plurality of microphones each positioned adjacent to at least one seat within the cabin.

5. The active noise reduction method of claim 1, further comprising:

judging the current road condition of the automobile according to the automobile body vibration signal;

and switching the filter coefficient to a preset filter coefficient corresponding to the current road condition.

6. The active noise reduction method according to any of claims 1 to 5, wherein the cabin acoustic field basis corresponding to the spatial point of the at least one microphone is determined according to a wave equation, a boundary function of an inner wall of the cabin of the automobile, and coordinates of the spatial point of the at least one microphone.

7. 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 1-6.

8. A computer readable storage medium comprising computer instructions stored thereon, which when executed by a processor, cause the processor to perform the active noise reduction method of any of claims 1-6.

9. An on-vehicle active noise reduction system, comprising:

the vibration sensor is used for acquiring a vehicle body vibration signal of the automobile;

the microphone is arranged in a cabin of the automobile and used for acquiring noise signals;

a chip for performing the active noise reduction method of any one of claims 1-6;

and the loudspeaker array is used for playing the noise reduction signal, wherein the loudspeaker array is arranged in the cabin of the automobile.

10. An automobile comprising the on-board active noise reduction system of claim 9.