Method and device for controlling engine noise of automobile

Abstract

The present invention discloses a control method and device for engine noise of automobiles, the control method comprising the following steps: calculating the theoretical update values ​​of gradient form of all loudspeakers and obtaining corresponding polar coordinates, respectively performing variable step length control on the amplitude gradient and phase gradient of the control weight; updating the control gradient and controlling the loudspeaker, ..., and outputting a noise reduction signal. The control method has the advantages of fast convergence speed and good noise reduction effect.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile noise reduction, and in particular to a method and a device for controlling engine noise of an automobile. Background Art

[0002] Engine noise can be considered as a cumulative combination of narrowband noises of multiple frequencies related to the speed. For single-frequency narrowband noise, the dual-weighted adaptive notch filter method is widely used. The notch filter method realizes adaptive convergence of control weights by gradient updating two reference signals with a phase difference of 90 degrees. The control weight parameters are multiplied by the corresponding reference signals and then accumulated to generate noise reduction waves.

[0003] The adaptive notch filter method has small memory usage, low computational complexity, and strong stability. This control method generally adjusts the convergence step size according to the amplitude of the two gradients, hoping to obtain faster convergence speed and better convergence accuracy. However, this adjustment method does not consider the amplitude-phase relationship formed by the two gradients. When the amplitude of the error signal is inconsistent with the phase change amplitude, directly correcting the step size according to the gradient amplitude will cause the dimension with a smaller change amplitude (amplitude or phase) to diverge and produce oscillation, reduce the convergence speed, and affect the noise reduction effect. Summary of the invention

[0004] In view of this, the main object of the present invention is to provide a method and device for controlling engine noise of a vehicle.

[0005] To achieve the above object, the technical solution of the present invention is implemented as follows: n microphones are arranged in the car compartment of the car. , , ..., and m speakers , , ..., , m and n are natural numbers, including the following steps: Calculate all speakers The gradient form theoretical update value and , p is a natural number, p=1, 2, ..., m; we get The corresponding polar coordinates ,get The corresponding polar coordinates , by controlling the amplitude gradient and phase gradient of the control weight with variable step size; updating the control gradient and controlling the speaker , , ..., Outputs a noise-reduced signal.

[0006] As an improvement of the embodiment of the present invention, the calculation of all speakers The gradient form theoretical update value and Specifically include: , , , ,in, For speakers To the microphone The secondary channel transfer function between , z is a discrete z-domain variable, For microphone The error signal is , r(k) is the speed of the engine, q is a natural number, q=1, 2, ..., n.

[0007] As an improvement of the embodiment of the present invention, the obtained The corresponding polar coordinates ,get The corresponding polar coordinates Specifically include: , , ,in, for The angle between the X axis and is the angle between the transfer function hp of the secondary channel and the X-axis.

[0008] As an improvement of the embodiment of the present invention, the variable step size control of the amplitude gradient and the phase gradient of the control weight specifically includes:

[0009] ,in, , and are constants, , ;

[0010] ,in, , and are constants, , ;

[0011] , , , .

[0012] As an improvement of the embodiment of the present invention, the updating control gradient and controlling the speaker , , ..., The output noise reduction signal specifically includes: , , ,in, is a constant; at discrete time k+1, based on Controlling the Speaker Output noise reduction signal, based on Controlling the Speaker Output noise reduction signal, ..., based on Controlling the Speaker Outputs a noise-reduced signal.

[0013] The embodiment of the present invention also provides a control device for engine noise of a car, wherein n microphones are arranged in the car compartment. , , ..., and m speakers , , ..., , m and n are both natural numbers, including the following modules: Information acquisition module, used to calculate all speakers The gradient form theoretical update value and , p is a natural number, p=1, 2, ..., m; we get The corresponding polar coordinates ,get The corresponding polar coordinates , by controlling the amplitude gradient and phase gradient of the control weight with variable step size; the noise reduction module is used to update the control gradient and control the speaker , , ..., Outputs a noise-reduced signal.

[0014] As an improvement of the embodiment of the present invention, , , , ,in, For speakers To the microphone The secondary channel transfer function between , z is a discrete z-domain variable, For microphone The error signal is , r(k) is the speed of the engine, q is a natural number, q=1, 2, ..., n.

[0015] As an improvement of the embodiment of the present invention, the information acquisition module is further used for: , , ,in, for The angle between the X axis and is the angle between the transfer function hp of the secondary channel and the X-axis.

[0016] As an improvement of the embodiment of the present invention, the information acquisition module is further used for:

[0017] ,in, , and are constants, , ;

[0018] ,in, , and are constants, , ;

[0019] , , , .

[0020] As an improvement of the embodiment of the present invention, the noise reduction module is further used for: , , ,in, is a constant; at discrete time k+1, based on Controlling the Speaker Output noise reduction signal, based on Controlling the Speaker Output noise reduction signal, ..., based on Controlling the Speaker Outputs a noise-reduced signal.

[0021] The control method and device for the engine noise of an automobile provided by the embodiment of the present invention have the following advantages: The embodiment of the present invention discloses a control method and device for the engine noise of an automobile, and the control method comprises the following steps: calculating the gradient form theoretical update value of all speakers and ;get The corresponding polar coordinates ,get The corresponding polar coordinates , by controlling the amplitude gradient and phase gradient of the control weight with variable step size; updating the control gradient and controlling the speaker , , ..., Output the noise reduction signal. This control method has the advantages of fast convergence speed and good noise reduction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a flow chart of a method for controlling engine noise in an embodiment of the present invention;

[0023] Figure 2 Schematic diagram of the coordinate base gradient form and polar coordinate gradient form for gradient form conversion;

[0024] Figure 3 Schematic diagram of a method for controlling engine noise in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below in conjunction with the embodiments shown in the accompanying drawings. However, the embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on the embodiments are all within the protection scope of the present invention.

[0026] The following description and accompanying drawings fully illustrate the specific embodiments of this article so that those skilled in the art can practice them. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. The scope of the embodiments of this article includes the entire scope of the claims, as well as all available equivalents of the claims. Herein, the terms "first", "second", etc. are only used to distinguish one element from another, without requiring or implying any actual relationship or order between these elements. In fact, the first element can also be called the second element, and vice versa. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the structure, device or equipment including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also include elements inherent to such structure, device or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the structure, device or equipment including the elements. Each embodiment is described in a progressive manner herein, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other.

[0027] The terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. in this document indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing this document and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of this document, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, it can also be the internal communication of two elements, it can be a direct connection, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0028] Embodiment 1 of the present invention provides a method for controlling engine noise of a vehicle, wherein n microphones are arranged in the vehicle compartment. , , ..., and m speakers , , ..., , m and n are both natural numbers, such as Figure 1 As shown, the following steps are included:

[0029] Step 101: Count All Speakers The gradient form theoretical update value and , p is a natural number, p=1, 2, ..., m; we get The corresponding polar coordinates ,get The corresponding polar coordinates , by performing variable step size control on the amplitude gradient and phase gradient of the control weight respectively.

[0030] Step 102: Update the control gradient and control the speaker , , ..., Output noise reduction signal to update control gradient and control the speaker , , ..., Outputs a noise-reduced signal.

[0031] The control method in the embodiment of the present invention converts the gradient representation of the multi-channel noise active control system from the coordinate basis form to the polar coordinate form, thereby realizing the decoupling of the amplitude scaling and phase rotation of the control weight, and eliminating the coupling effect caused by the change step size of the two weight gradients in the coordinate basis gradient form. By performing variable step size control on the amplitude gradient and phase gradient of the control weight respectively, it is avoided that when the numerical difference between the amplitude and phase of the gradient is large, the gradient of the dimension of the small value caused by the change step size based on the coordinate basis form is ignored in the calculation, and the convergence gradient amplitude of different dimensions is normalized, thereby eliminating the convergence oscillation phenomenon caused by the large difference in the numerical magnitude of the error dimension, and achieving a faster convergence speed while achieving a higher convergence accuracy and a better noise reduction effect.

[0032] In this embodiment, Figure 3 As shown, the calculation of all speakers The gradient form theoretical update value and Specifically include: , , , ,in, For speakers To the microphone The secondary channel transfer function between , z is a discrete z-domain variable, For microphone The error signal is , r(k) is the speed of the engine, q is a natural number, q=1, 2, ..., n.

[0033] Here, each microphone The error signal With corresponding speakers Transfer Function After convolution, the sum is performed and then combined with two reference signals respectively. , Perform convolution to obtain the theoretical update value of the gradient coordinate basis of this speaker and , which represent the update gradients of the X and Y axes in the plane where the secondary channel transfer function is located. The calculation is repeated according to the number of speakers to obtain the theoretical update gradients of all speakers in the coordinate basis of the secondary channel transfer function. Where q = 1, 2, ..., n, p = 1, 2, ..., m.

[0034] In this embodiment, Figure 3 As shown, the obtained The corresponding polar coordinates ,get The corresponding polar coordinates Specifically include: , , ,in, for The angle between the X axis and is the angle between the transfer function hp of the secondary channel and the X-axis.

[0035] like Figure 2 Sub-figure a in FIG shows the coordinate basis gradient form of the gradient form conversion, Figure 2 Subfigure b in shows the polar coordinate gradient form of the gradient form conversion. As shown, the theoretical update gradient is a set of vectors based on the coordinate basis of the coordinate system where the transfer function is located. This set of vectors is mathematically orthogonal, representing the gradient change values ​​of the X and Y axes respectively, but they are mutually coupled in the physical meaning of amplitude and phase. The amplitude change and phase change of the overall output of the speaker are represented by two orthogonal gradient values. Directly setting different weights according to their respective amplitudes to adjust the gradient update step size causes the gradient correspondence between the X and Y axes to be changed, destroying the inherent amplitude and phase meanings. The coordinate basis representation of the theoretical update gradient can be converted into a polar coordinate gradient form representing the output amplitude and phase of the speaker according to the above formula to achieve orthogonal decoupling in the physical sense.

[0036] In this embodiment, Figure 3 As shown, the variable step size control of the amplitude gradient and the phase gradient of the control weight specifically includes:

[0037] ,in, , and are constants, , ;

[0038] ,in, , and are constants, , ;

[0039] , , , .

[0040] According to engineering experience and actual test data, Set the upper threshold (i.e. constant ), set the lower threshold (i.e. constant ),for Set the upper threshold (i.e. constant ), set the lower threshold (i.e. constant ), to avoid excessive changes in weight gain due to numerical fluctuations. and It can be understood as setting the lower limit of weight gain to avoid too small weight gain affecting the filter convergence speed. In order to ensure that the step size does not exceed the upper limit of stability, the gain is set to change linearly from 1 to the minimum gain value according to the gradient change size. According to the above formula, the polar coordinate form gradient after considering the step gain is converted into the coordinate basis form gradient as the modified coordinate basis form gradient update value. The modified gradient update value not only retains the amplitude and phase relationship in the original gradient, but also realizes the dynamic change of the step size by modifying the specific values ​​of the amplitude and phase, thereby improving the calculation accuracy and convergence speed of the algorithm.

[0041] In this embodiment, Figure 3 As shown, the update control gradient and control the speaker , , ..., The output noise reduction signal specifically includes: , , ,in, is a constant; at discrete time k+1, based on Controlling the Speaker Output noise reduction signal, based on Controlling the Speaker Output noise reduction signal, ..., based on Controlling the Speaker Outputs a noise-reduced signal.

[0042] Here, according to the corrected coordinate basis formal gradient, the speaker noise reduction control weight is updated according to the above formula, and the noise reduction signal is calculated according to the above formula. The weight update and noise reduction signal calculation are performed for each speaker cycle, and the noise reduction signal is output after all calculations are completed to achieve noise cancellation control.

[0043] Embodiment 2 of the present invention provides a control device for engine noise of a car, wherein n microphones are arranged in the car compartment. , , ..., and m speakers , , ..., , m and n are both natural numbers, including the following modules:

[0044] Information acquisition module, used to calculate all speakers The gradient form theoretical update value and , p is a natural number, p=1, 2, ..., m; we get The corresponding polar coordinates ,get The corresponding polar coordinates , by performing variable step size control on the amplitude gradient and phase gradient of the control weight respectively;

[0045] Noise reduction module that updates the control gradient and controls the speakers , , ..., Outputs a noise-reduced signal.

[0046] In this embodiment, the information acquisition module is also used to: , , , ,in, For speakers To the microphone The secondary channel transfer function between , z is a discrete z-domain variable, For microphone The error signal is , r(k) is the speed of the engine, q is a natural number, q=1, 2, ..., n.

[0047] In this embodiment, the information acquisition module is also used to: , , ,in, for The angle between the X axis and is the angle between the transfer function hp of the secondary channel and the X-axis.

[0048] In this embodiment, the information acquisition module is also used to:

[0049] ,in, , and are constants, , ;

[0050] ,in, , and are constants, , ;

[0051] , , , .

[0052] In this embodiment, the noise reduction module is also used for:

[0053] , , ,in, is a constant; at discrete time k+1, based on Controlling the Speaker Output noise reduction signal, based on Controlling the Speaker Output noise reduction signal, ..., based on Controlling the Speaker Outputs a noise-reduced signal.

[0054] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0055] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling engine noise of a car, wherein n microphones are arranged in the car compartment , , ..., and m speakers , , ..., , m and n are both natural numbers, characterized in that, The following steps are involved: , , , ,in, For speakers To the microphone The secondary channel transfer function between , z is a discrete z-domain variable, For microphone The error signal is, r(k) is the speed of the engine, q is a natural number, q=1, 2, ..., n, p is a natural number, p=1, 2, ..., m; , , ,in, for The angle between the X axis and is the angle between the transfer function hp of the secondary channel and the X-axis, ,in, , and are constants, , ; ,in, , and are constants, , ; , , , ; , , ,in, is a constant; at discrete time k+1, based on Controlling the Speaker Output noise reduction signal, based on Controlling the Speaker Output noise reduction signal, ..., based on Controlling the Speaker Outputs a noise-reduced signal.

2. A control device for engine noise of a car, wherein n microphones are arranged in the car compartment of the car , , ..., and m speakers , , ..., , m and n are both natural numbers, characterized in that, Includes the following modules: Information acquisition module, used to , , , ,in, For speakers To the microphone The secondary channel transfer function between , z is a discrete z-domain variable, For microphone The error signal, r(k) is the speed of the engine, q is a natural number, q=1, 2, ..., n p is a natural number, p=1, 2, ..., m; , , ,in, for The angle between the X axis and is the angle between the transfer function hp of the secondary channel and the X-axis, ,in, , and are constants, , ; ,in, , and are constants, , ; , , , ; Noise reduction module for , , ,in, is a constant; at discrete time k+1, based on Controlling the Speaker Output noise reduction signal, based on Controlling the Speaker Output noise reduction signal, ..., based on Controlling the Speaker Outputs a noise-reduced signal.

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