VEHICLE ROAD NOISE CONTROL METHOD AND SYSTEM BASED ON ACTIVE NOISE CANCELLATION, ELECTRONIC EQUIPMENT AND STORAGE MEDIUM

Abstract

Disclosed are a method and system for controlling vehicle road noise based on active noise reduction. The method includes: acquiring a multi-channel reference signal of vehicle road noise; generating a control signal based on a coefficient of a filter at a current time and the multi-channel reference signal, and feeding to a sound reproduction device of the vehicle; acquiring acoustical signals at a plurality of sampling positions inside a compartment of the vehicle to obtain a vector of an error signal; filtering the reference signal to obtain a filtered reference signal; writing the filtered reference signal in a matrix form; and updating the coefficient of the filter. The method actively reduces the road noise caused by friction between vehicle tires and road surface, reduces interior noise pollution, and has a relatively fast convergence speed and relatively high accuracy.

Claims

1. A method for controlling vehicle road noise based on active noise reduction, comprising: step S1, acquiring a multi-channel reference signal of vehicle road noise, denoted by x.sub.k(n), k32 1,2, . . . , K, K being a channel number of the multi-channel reference signal, n representing a sampling time; step S2, generating a control signal based on a coefficient of a filter at a current time and the multi-channel reference signal, and feeding to a sound reproduction device of a vehicle; step S3, acquiring acoustical signals at a plurality of sampling positions inside a compartment of the vehicle to obtain a vector e(n) of an error signal; step S4, filtering the multi-channel reference signal to obtain a filtered reference signal {circumflex over (x)}.sub.k,l,m(n), as shown in the following equation, ${\hat{x}}_{k,l,m}\left(n\right)=\underset{i=0}{\overset{N-1}{.Math.}}{s}_{l,m}\left(i\right)x_k\left(n-i\right),$ $k=1,2,.Math.,K;l=1,2,.Math.,L;m=1,2,.Math.,M$ wherein N is a length of the filter, L is a channel number of the sound reproduction device, M is a number of the plurality of sampling positions, S.sub.l,m represents a transfer function from a l-th loudspeaker to a m-th sampling position, S.sub.l,m(i) is an i-th coefficient of the filter; x.sub.k(ni) represents a k-th channel of the multi-channel reference signal at previous i sampling times; step S5, writing the filtered reference signal in a matrix form as shown below, $\hat{x}\left(n\right)=\left[\begin{array}{ccc}{\hat{x}}_{1,1,1}\left(n\right)& .Math.& {\hat{x}}_{1,1,M}\left(n\right)\\ .Math.& & .Math.\\ {\hat{x}}_{K,L,1}\left(n\right)& .Math.& {\hat{x}}_{K,L,M}\left(n\right)\end{array}\right]R^{K.Math.LM}$ $\hat{X}\left(n\right)=\left[\begin{array}{c}\hat{x}\left(n\right)\\ .Math.\\ \hat{x}\left(n-N+1\right)\end{array}\right]R^{K.Math.L.Math.NM}$ wherein {circumflex over (x)}(n) represents a matrix with a size of K.Math.L rows and M columns, of which elements are composed of the filtered reference signal {circumflex over (x)}.sub.k,l,m(n) at a current sampling time; {circumflex over (X)}(n) represents a matrix with a size of K.Math.L.Math.N rows and M columns, of which elements are composed of the filtered reference signal at the current sampling time and previous sampling times, {circumflex over (x)}(nN+1) represents a matrix with a size of K.Math.L rows and M columns, of which elements are composed of the filtered reference signal {circumflex over (x)}.sub.k,l,m(nN+1) at previous (N1)-th time, R.sup.K.Math.LM represents a matrix with K.Math.L rows and M columns, and R.sup.K.Math.L.Math.NM represents a matrix with K.Math.L.Math.N rows and M columns; and step S6, updating the coefficient of the filter in step S2 according to the following equation, $w\left(n+1\right)=w\left(n\right)+{\stackrel{}{X}\left(n\right)\left[{\stackrel{}{X}\left(n\right)}^T\stackrel{}{X}\left(n\right)+I\right]}^{-1}e\left(n\right)$ wherein w(n+1) represents an updated coefficient of the filter, which is used to generate an output control signal by filtering at next sampling time n+1, w (n) represents a coefficient of the filter at the current time, is a convergence factor, is a regularization factor, and I is an identity matrix.

2. The method for controlling vehicle road noise of claim 1, wherein, a matrix form of the coefficient of the filter w(n) is: $w\left(n\right)={\left[\left[w_{1,1}\left(0\right),.Math.,w_{J,K}\left(0\right)\right].Math.\left[w_{1,1}\left(N-1\right),.Math.,w_{J,K}\left(N-1\right)\right]\right]}^T{R}^{K.Math.L.Math.N1}$ wherein R.sup.K.Math.L.Math.N1 represents a matrix with K.Math.L.Math.N rows and 1 column, and wherein, in step S2, the control signal is represented as the following equation: $y_l\left(n\right)=\underset{i=0}{\overset{N-1}{.Math.}}{w}_{k,l}\left(i\right)x_k\left(n-i\right),l=1,2,.Math.,L;k=1,2,.Math.,K$ wherein W.sub.k,l(i) is an element in the matrix w(n), representing an i-th order coefficient of the filter with an input being a k-th reference signal and an output being an l-th sound reproduction device, K.Math.L filters are provided, with an order of N, each order i of the K.Math.L filters is combined into an array form [W.sub.1,1(i), . . . , W.sub.J,K(i)], and all order coefficients together form w(n).

3. The method for controlling vehicle road noise as of claim 1, wherein, in step S1, a vibration signal caused by a friction between wheels and a road surface is acquired through a vibrating sensor and is used as the reference signal.

4. The method for controlling vehicle road noise of claim 3, wherein, the vibrating sensor is arranged on a bottom plate of the vehicle.

5. The method for controlling vehicle road noise of claim 1, wherein, in step S1, a noise signal caused by a friction between wheels and a road surface is acquired through a first microphone and is used as the reference signal.

6. The method for controlling vehicle road noise of claim 5, wherein, the first microphone is arranged at a position adjacent to the wheels of the vehicle.

7. The method for controlling vehicle road noise of claim 1, wherein, in step S2, the sound reproduction device comprises a vehicle-mounted loudspeaker arranged inside the compartment of the vehicle.

8. The method for controlling vehicle road noise of claim 1, wherein, in step S3, acoustical signals inside the compartment of the vehicle are acquired through a plurality of second microphones, and the plurality of second microphones is arranged at the plurality of sampling positions inside the compartment of the vehicle.

9. A system for controlling vehicle road noise based on active noise reduction, comprising: a road noise acquisition device for acquiring a noise or vibration signal caused by friction between wheels and a road surface; a control device for generating a multi-channel reference signal based on the noise or vibration signal acquired by the road noise acquisition device, and generating a control signal based on a coefficient of a filter at a current time and the multi-channel reference signal; a sound reproduction device for generating a secondary sound wave for canceling noise in a compartment based on the control signal sent by the control device; and an error signal acquisition device for acquiring acoustical signals at a plurality of positions of the compartment to obtain a vector e(n) of an error signal; wherein the control device is further configured to filter the multi-channel reference signal to obtain a filtered reference signal and write the filtered reference signal into a matrix form, and to update the coefficient of the filter based on the matrix form of the filtered reference signal and the vector of the error signal according to the following equation, $w\left(n+1\right)=w\left(n\right)+{\stackrel{}{X}\left(n\right)\left[{\stackrel{}{X}\left(n\right)}^T\stackrel{}{X}\left(n\right)+I\right]}^{-1}e\left(n\right)$ wherein w(n+1) represents an updated coefficient of the filter, w(n) represents a coefficient of the filter at the current time, is a convergence factor, {circumflex over (X)}(n) is the matrix form of the filtered reference signal, is a regularization factor, and I is an identity matrix.

10. The vehicle road noise control system of claim 9, wherein, the road noise acquisition device comprises a vibrating sensor arranged on a bottom plate of a vehicle or a first microphone arranged at a position adjacent to a wheel of the vehicle, and wherein the error signal acquisition device comprises a plurality of second microphones arranged at a plurality of sampling positions inside the compartment of the vehicle.

11. The system of claim 9, wherein, the sound reproduction device comprises a vehicle-mounted loudspeaker arranged inside the compartment of a vehicle.

12. The vehicle road noise control system of claim 9, wherein, the control device is configured to: filter the multi-channel reference signal to obtain a filtered reference signal {circumflex over (x)}.sub.k,l,m(n), as shown in the following equation, ${\hat{x}}_{k,l,m}\left(n\right)=\underset{i=0}{\overset{N-1}{.Math.}}{s}_{l,m}\left(i\right)x_k\left(n-i\right),$ $k=1,2,.Math.,K;l=1,2,.Math.,L;m=1,2,.Math.,M$ wherein, N is a length of the filter, L is a channel number of the sound reproduction device, M is a number of the plurality of sampling positions, S.sub.l,m represents a transfer function from a l-th loudspeaker to a m-th sampling position, S.sub.l,m(i) is an i-th coefficient of the filter; x.sub.k(ni) represents a k-th channel of the multi-channel reference signal at previous i sampling times; and write the filtered reference signal in a matrix form as shown below, $\hat{x}\left(n\right)=\left[\begin{array}{ccc}{\hat{x}}_{1,1,1}\left(n\right)& .Math.& {\hat{x}}_{1,1,M}\left(n\right)\\ .Math.& & .Math.\\ {\hat{x}}_{K,L,1}\left(n\right)& .Math.& {\hat{x}}_{K,L,M}\left(n\right)\end{array}\right]R^{K.Math.LM}$ $\hat{X}\left(n\right)=\left[\begin{array}{c}\hat{x}\left(n\right)\\ .Math.\\ \hat{x}\left(n-N+1\right)\end{array}\right]R^{K.Math.L.Math.NM}$ wherein {circumflex over (x)}(n) represents a matrix with a size of K.Math.L rows and M columns, of which elements are composed of the filtered reference signal {circumflex over (x)}.sub.k,l,m(n) at the a current sampling time; {circumflex over (X)}(n) represents a matrix with a size of K.Math.L.Math.N rows and M columns, of which elements are composed of the filtered reference signal at the current sampling time and historical sampling times, {circumflex over (x)}(nN+1) represents a matrix with a size of K.Math.L rows and M columns, of which elements are composed of the filtered reference signal {circumflex over (x)}.sub.k,l,m(nN+1) at previous (N-1)-th time, R.sup.K.Math.LM represents a matrix with K.Math.L rows and M columns, and R.sup.K.Math.L.Math.NM represents a matrix with K.Math.L.Math.N rows and M columns.

13. The vehicle road noise control system of claim 9, wherein, the control signal is represented by the following equation: $y_l\left(n\right)=\underset{i=0}{\overset{N-1}{.Math.}}{w}_{k,l}\left(i\right)x_k\left(n-i\right),l=1,2,.Math.,L;k=1,2,.Math.,K,\mathrm{and}$ wherein w.sub.k,l(i) is an element in the matrix w(n), representing an i-th order coefficient of the filter with an input being a k-th reference signal and an output being a l-th sound reproduction device. K.Math.L filters are provided, with an order of N, each order i of the K.Math.L filters is combined into an array form [W.sub.1,1(i), . . . , w.sub.J,K(i)], all order coefficients together form w(n).

14. (canceled)

15. A computer readable storage medium, wherein, the computer readable storage medium stores a computer program, the computer program, when executed by a processor, implements the vehicle road noise control method of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] For more clearly explaining the technical solutions in the embodiments of the present disclosure, the accompanying drawings used to describe the embodiments are simply introduced in the following. Apparently, the below described drawings merely show a part of the embodiments of the present disclosure, and those skilled in the art can obtain other drawings according to the accompanying drawings without creative work.

[0053] FIG. 1 is a flow chart of an MIMO MNFxLMS algorithm according to an embodiment of the present disclosure.

[0054] FIG. 2 is a block diagram of the MIMO MNFxLMS algorithm according to an embodiment of the present disclosure.

[0055] FIG. 3 is a block diagram of a vehicle road noise control system according to an embodiment of the present disclosure.

[0056] FIG. 4 is a comparison chart of the convergence performance of three algorithms, namely MIMO FxLMS, MIMO NFxLMS, and MIMO MNFxLMS algorithms at Position 1.

[0057] FIG. 5 is a comparison chart of the convergence performance of three algorithms, namely MIMO FxLMS, MIMO NFxLMS, and MIMO MNFxLMS algorithms at Position 2.

DETAILED DESCRIPTION

[0058] In the following, the preferable embodiments of the present disclosure are explained in detail combining with the accompanying drawings so that the advantages and features of the present disclosure can be easily understood by the skilled persons in the art. It should be noted that the explanation on these implementations is to help understanding of the present disclosure, and is not intended to limit the present disclosure.

[0059] This embodiment provides an active noised reduction-based vehicle road noise control method, which adopts an improved multi-channel normalized FxLMS (referred to as MIMO MNFxLMS, Multiple Inputs Multiple Outputs Modified Normalized Filtered-x Least Mean Square) algorithm to actively reduce the road noise caused by friction between vehicle tires and the road surface. Combining with FIG. 1 and FIG. 2, this method is specifically described as below.

[0060] (1) Acquisition of a reference signal

[0061] At each sampling time n, reference signals are acquired from sensors, for example vibration signals are acquired by a vibration sensor (typically, arranged on the bottom plate of the vehicle), or sound signals are acquired by a microphone (typically, arranged on a position near the wheels of the vehicle). There are K-channel reference signals, denotes as x.sub.k(n), k=1,2, . . . , K.

[0062] (2) Generation of a control signal

[0063] A control signal y.sub.l(n) is generated based on a parameter W.sub.k,l(n) at the current time and the reference signal obtained at the previous step, and is fed to the sound reproduction device, specifically in this embodiment, the sound reproduction device comprises a vehicle-mounted loudspeaker.

[00010]$y_l\left(n\right)=\underset{i=0}{\overset{N-1}{.Math.}}{w}_{k,l}\left(i\right)x_k\left(n-i\right),l=1,2,.Math.,L;k=1,2,.Math.,K$

[0064] Wherein, the number of the channels of the loudspeaker is L, and the order of the adaptive filter is N. W.sub.k,l(i) represents that the input of the filter is the k-th reference signal, and the output is the l-th control sound source, namely the loudspeaker here.

[0065] (3) Generation of a filtered reference signal

[0066] An important step in the FxLMS algorithm is to filter the reference signals. It is generally believed that the transfer function of the secondary channel comprises a transmission path of the digital control signal y(n) through a DAC module, an analog filter, a power amplifier module, a loudspeaker, a spatial propagation of sound waves, a microphone, an analog filter, and an ADC module. The transfer function S of the secondary channel is obtained through online or offline system identification methods, expressed as S, which is a digital filter of length N, represented as S.sub.l,m, l=1,2, . . . , L; m=1,2, . . . , M, represents the transfer function between the l-th loudspeaker to the m-th microphone. M is the number of microphones. The filtered reference signal obtained through calculation is:

[00011]${\hat{x}}_{k,l,m}\left(n\right)=\underset{i=0}{\overset{N-1}{.Math.}}{s}_{l,m}\left(i\right)x_k\left(n-i\right),$$k=1,2,.Math.,K;l=1,2,.Math.,L;m=1,2,.Math.,M$

[0067] (4) The filtered reference signal is written into matrix form

[00012]$\hat{x}\left(n\right)=\left[\begin{array}{ccc}{\hat{x}}_{1,1,1}\left(n\right)& .Math.& {\hat{x}}_{1,1,M}\left(n\right)\\ .Math.& & .Math.\\ {\hat{x}}_{K,L,1}\left(n\right)& .Math.& {\hat{x}}_{K,L,M}\left(n\right)\end{array}\right]R^{K.Math.LM}$$\hat{X}\left(n\right)=\left[\begin{array}{c}\hat{x}\left(n\right)\\ .Math.\\ \hat{x}\left(n-N+1\right)\end{array}\right]R^{K.Math.L.Math.NM}$

[0068] where, R.sup.K.Math.LM represents a matrix with K.Math.L rows and M columns, R.sup.K.Math.L.Math.NM represents a matrix with K.Math.L.Math.N rows and M columns.

[0069] (5) According to error signals e.sub.m(n) acquired from each microphone, obtain the vector of the error signal, represented as

[00013]$e\left(n\right)={\left[e_1\left(n\right),.Math.,e_M\left(n\right)\right]}^T{R}^{M1}$

[0070] wherein, there are M microphone signals.

[0071] (6) The parameter w(n) of the control filter is updated, which is represented

[00014]$w\left(n+1\right)=w\left(n\right)+{\stackrel{}{X}\left(n\right)\left[{\stackrel{}{X}\left(n\right)}^T\stackrel{}{X}\left(n\right)+I\right]}^{-1}e\left(n\right)$

[0072] as

[0073] Wherein, is the regularization factor, usually taken to one decimal place based on experience. I is an identity matrix. is a convergence factor, generally selected a number based on experience, and its value range is usually between 0 and 2. Wherein, the matrix form of w(n) is

[00015]$w\left(n\right)={\left[\left[w_{1,1}\left(0\right),.Math.,w_{J,K}\left(0\right)\right].Math.\left[w_{1,1}\left(N-1\right),.Math.,w_{J,K}\left(N-1\right)\right]\right]}^T{R}^{K.Math.L.Math.N1}$

[0074] wherein, the definition of W.sub.k,l(i) is explained in step (2).

[0075] Referring to FIG. 3, the vehicle road noise control system according to this embodiment comprises: [0076] a road noise acquisition device 101, for acquiring a noise or vibration signal caused by the friction between the wheels and the road surface; [0077] a control device 102, for generating a multi-channel reference signal based on the noise or vibration signal acquired by the road noise acquisition device 101, and for generating a control signal based on a coefficient of a filter at the current time and the multi-channel reference signal; [0078] a sound reproduction device 103, for generating a secondary sound wave for canceling noise in the compartment 200 based on the control signal sent by the control device 102; and [0079] an error signal acquisition device 104, for acquiring acoustical signals at a plurality of positions of the compartment 200 to obtain a vector e(n) of an error signal;

[0080] wherein, the control device 102 is further configured to filter the reference signal and write it into a matrix form, and to update the coefficient of the filter based on the matrix form of the filtered reference signal and the vector of the error signal according to the following equation,

[00016]$w\left(n+1\right)=w\left(n\right)+{\stackrel{}{X}\left(n\right)\left[{\stackrel{}{X}\left(n\right)}^T\stackrel{}{X}\left(n\right)+I\right]}^{-1}e\left(n\right)$

[0081] wherein, w(n+1) represents the updated coefficient of the filter, w(n) represents the coefficient of the filter at the current time, u is the convergence factor, {circumflex over (X)}(n) is the matrix form of the filtered reference signal, is the regularization factor, and I is an identity matrix.

[0082] The road noise acquisition device 101 is electrically connected to an input end of the control device 102, and specifically comprises a vibrating sensor arranged on the bottom plate of the vehicle or a first microphone arranged at a position near the wheels of the vehicle. The error signal acquisition device 104 is electrically connected to an input end of the control device 102, and specifically comprises a plurality of second microphones arranged at a plurality of sampling positions inside the compartment 200. The sound reproduction device 103 is electrically connected to an output end of the control device 102, and specifically comprises a vehicle-mounted loudspeaker, which is arranged inside the compartment 200 of the vehicle or to emit sound at least to the compartment of the vehicle, and includes but is not limited to: headrest loudspeakers, roof loudspeakers, door panel loudspeakers, etc.

Simulation Example

[0083] The convergence performance of the algorithm was simulated. In the simulation experiment, the target noise was a broadband signal with a frequency band covering 80 Hz-320 Hz, which is a typical frequency band distribution of road noise. The noise signal was a white noise signal generated through a bandpass filter. The number of channels of the reference signal was set as K=2, the number of loudspeakers was set as L=5, and the number of microphones for acquiring error signals was set as M=5. The transfer functions between the loudspeakers and microphones, also are the transfer functions of the secondary channels mentioned above, were obtained through real vehicle acquisition. In the simulation experiment, the variation relationships of noise energy with iteration times (corresponding to time) before and after active noise control were respectively compared, and more importantly, the traditional multi-channel FxLMS algorithm (MIMO FxLMS), the existing multi-channel normalized FxIMS algorithm (MIMO NFxLMS), and the improved normalized FxLMS algorithm (MIMO MNFxLMS) proposed in the present disclosure were compared. FIG. 4 shows the variation relationships of the residual noise signal amplitudes with iterations at the first position, and it can be seen from FIG. 4 that the traditional FxLMS algorithm has a certain denoising effect; after adopting normalization, the algorithm converges faster; using the improved normalization algorithm of the present disclosure achieves faster convergence results. FIG. 5 shows the variation relationships of the residual noise signal amplitudes with iterations at the fifth position, and it can be seen from FIG. 5 that the traditional FxLMS algorithm has almost no denoising effect; after adopting normalization processing, there is a significant noise reduction effect, and if adopting the improved normalization algorithm of the present disclosure, which considers the coupling effect between channels, faster convergence speed and larger noise reduction can be achieved.

[0084] Those skilled in the art can understand that unless specifically stated, the singular forms a, an, said, and the used herein may also include the plural form. It should be further understood that wording comprises used in the description of this application refers to the presence of a feature, an integer, a step, an operation, an element and/or an assembly, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, assemblies and/or combinations thereof.

[0085] It should be further understood that in the present disclosure, plurality refers to two or more, and other quantifiers are similar. And/or describes the association relationship of the associated objects, indicating that there can be three types of relationships, for example, A and/or B, which can represent: the existence of A alone, the coexistence of A and B, and the existence of B alone. The character / generally indicates that the objects associated before and after are in an or relationship. The singular forms a, said, and the are intended to include the plural forms as well, unless the context clearly dictates otherwise.

[0086] It can be further understood that the terms first, second, etc. are used to describe various information, but this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other and do not indicate a specific order or degree of importance. In fact, expressions such as first and second can be used interchangeably. For example, without departing from the scope of the present disclosure, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information.

[0087] The embodiments described above are only for illustrating the technical concepts and features of the present disclosure, are preferred embodiments, and are intended to make those skilled in the art being able to understand the present disclosure and thereby implement it, and should not be concluded to limit the protective scope of this disclosure. Any equivalent variations or modifications according to the spirit of the present disclosure should be covered by the protective scope of the present disclosure.