CN113160787A

CN113160787A - Road noise active control system and method based on hybrid feedback architecture

Info

Publication number: CN113160787A
Application number: CN202010073888.7A
Authority: CN
Inventors: 宋海生; 张新宇
Original assignee: Shaanxi Heavy Duty Automobile Co Ltd
Current assignee: Shaanxi Heavy Duty Automobile Co Ltd
Priority date: 2020-01-22
Filing date: 2020-01-22
Publication date: 2021-07-23

Abstract

The invention relates to a noise active control system and method based on a hybrid feedback framework, which comprises a plurality of acceleration sensors, a plurality of loudspeakers, a plurality of microphones and an active control unit, wherein the acceleration sensors are respectively arranged at two ends of a front shaft and two ends of a rear shaft and are used for acquiring a shaft head acceleration signal caused by road surface excitation, the microphones are respectively arranged at the head positions of drivers or members and are used for synchronously acquiring noise signals in a vehicle in real time, each vehicle door is provided with the loudspeaker, meanwhile, the front part of a cab of a commercial vehicle is provided with the loudspeakers and is used for synchronously releasing sound waves with equal amplitude and opposite phase with road surface noise, the excitation signals acquired by the acceleration sensors and the noise signals acquired by the microphones in real time, then the two signals are input into the active control unit, and the active control unit analyzes and processes the two signals, the sound wave with the same amplitude and opposite phase with the noise in the vehicle is output to the loudspeaker, so that the elimination or suppression of the road noise is realized.

Description

Road noise active control system and method based on hybrid feedback architecture

Technical Field

The invention belongs to the technical field of noise control, and particularly relates to a system and a method for active control of noise based on a hybrid feedback architecture.

Background

Road noise is one of the main sources of automobile noise, the excitation of the road noise is caused by the interaction between tires and the road surface, the transmission path of the road noise is mainly air transmission and structure transmission, the air transmission noise (>300Hz acoustic component) can be isolated by an acoustic package, but the structure transmission noise (<300Hz acoustic component) cannot be eliminated, and particularly for new energy vehicles, the road noise transmitted through the structure becomes increasingly annoying due to the fact that the engine noise masking effect is not achieved.

Based on the above reasons, an active control technology of road noise is proposed, and the basic principle is that sound waves with equal amplitude and opposite phase to road noise signals are played through a loudspeaker, so as to achieve the purpose of eliminating or weakening structure propagation road noise.

However, the low-frequency path noise has both a narrow-band signal characteristic with an obvious characteristic and a wide-range energy distribution characteristic, when the front feedback system architecture is used alone, the problem that the attenuation amplitude of non-modal related frequency components is small can occur, and when the rear feedback system architecture is used alone, the problem that the identification precision of main components of the path noise is poor can occur, so that the noise reduction effect of the active control system of the path noise is not ideal.

Disclosure of Invention

The invention aims to provide a road noise active control system based on a hybrid feedback framework, which is characterized in that an acceleration sensor arranged at a shaft head position is used for acquiring an excitation signal from a road surface in real time, microphones arranged beside ears of a driver and passengers are used for acquiring a noise signal in a vehicle in real time, then the two signals are input into an active control unit, and the active control unit analyzes and processes the two signals and outputs a sound wave with the same amplitude and opposite phase with the noise in the vehicle to a loudspeaker, so that the elimination or suppression of the road noise is realized.

In order to solve the problems in the background art, the invention is realized by the following technical scheme:

a kind of noise initiative control system based on mixed feedback framework, including multiple acceleration sensors, multiple loudspeakers, multiple microphones and initiative control unit;

the acceleration sensors are respectively arranged at two ends of the front shaft and two ends of the rear shaft and are used for acquiring a shaft head acceleration signal caused by road excitation to serve as a front feedback signal x (n);

the microphones are respectively arranged at the head positions of drivers or members and used for synchronously acquiring noise signals in the vehicle in real time as residual signals e (n);

each door is provided with a loudspeaker, and meanwhile, the front part of a cab of the commercial vehicle is provided with a plurality of loudspeakers for synchronously releasing sound waves with equal amplitude and opposite phase with road noise, wherein the signal is y (n).

As a further description of the invention: the active control unit comprises a data acquisition system, a DSP discrete signal processing module and a filter unit, wherein the filter unit comprises a front feedback adaptive filter A (z) and a rear feedback adaptive filter C (z), the active control unit adopts an FXLMS algorithm, and the algorithm enables the average potential energy of a residual signal e (n) to be minimum by adjusting weight vector matrixes of A (z) and C (z) in real time on line.

As a further description of the invention: the transfer function between the acceleration sensor and the microphone is P (z), the transfer function between the loudspeaker and the microphone is S (z), and the front feedback part and the rear feedback part are both provided with filters

For simulating the influence of the transmission path s (z).

As a further description of the invention: the adaptive adjustment of the feedforward adaptive filter A (z) adopts an LMS algorithm, and the input signal is a feedforward reference signal

And residual signal e (n).

As a further description of the invention: the adaptive adjustment LMS algorithm of the post-feedback adaptive filter C (z) has the input signal of a post-feedback reference signal

Of the residual signal e (n), wherein

The second purpose of the invention is to provide a road noise active control method based on a mixed feedback architecture, and the elimination and suppression of low-frequency road noise (sound component less than 300 Hz) are realized by combining a system architecture adopting front feedback and rear feedback.

The invention is realized by the following technical scheme:

a method for controlling noise actively based on a hybrid feedback architecture comprises the following steps:

step S1: the acceleration sensor picks up a road surface excitation signal x (n) and outputs the road surface excitation signal x (n) to the active control unit;

step S2: intercepting a signal in a frequency band range of 0-300HZ by an active control unit;

step S3: will signal with

Convolution is carried out, and meanwhile, residual signals e (n) acquired by the microphone and the residual signals e (n) are output to an LMS algorithm of a front feedback part;

step S4: updating the weight vector matrix of the feedforward adaptive filter A (z);

step S5: post feedback signal

And

convolution is carried out, and meanwhile, residual signals e (n) acquired by the microphone and the residual signals e (n) are output to an LMS algorithm of a post-feedback part;

step S6: updating the weight vector matrix of the post-feedback adaptive filter C (z);

step S7: convolving the reference signal x (n) with the updated feedforward adaptive filter A (z), and obtaining the post-feedback signal

Convolving with the updated post-feedback adaptive filter C (z), simultaneously superposing the two to form a signal y (n), and inputting the signal y (n) into a loudspeaker to enable the loudspeaker to emit reverse-phase sound waves;

step S8: convolving the inverted sound wave output y (n) with S (z), convolving the input signal x (n) with P (z), simultaneously superposing the two to obtain a residual signal e (n), and calculating to obtain the average sound potential energy of the residual signal.

As a further description of the invention: and step S1 to step S8 are completed in an iteration loop, the step length of one iteration is set to 0.5S, when the average acoustic potential energy calculated in step S6 reaches the minimum value, the system stops operating and enters a convergence state, and when the road excitation changes, the system operates again, and the iteration loop is performed to adjust so that the average acoustic potential energy reaches the minimum value and reaches a new convergence state.

As a further description of the invention: the steps of obtaining the transfer function p (z) between the acceleration sensor and the microphone are as follows:

step S1: detaching the tire assembly, and exciting by using a vibration exciter at the position of a shaft head by adopting a frequency sweeping signal of 0-300 Hz;

step S2: picking up noise signals at a microphone in the vehicle, and processing the two signals to obtain a frequency response function FRF between a shaft head and the microphone;

step S3: exciting the positions of the axle heads of the plurality of wheels one by one;

step S4: a multi-order FRF function matrix is obtained and written into the active control unit as the characteristic curve of the transfer function P (z).

As a further description of the invention: the steps of obtaining the transfer function s (z) between the loudspeaker and the microphone are as follows:

step S1: a medium-low frequency volume sound source is arranged near a loudspeaker, and meanwhile, a sound signal of 0-300Hz is adopted for sweep frequency excitation;

step S2: picking up a noise signal at an in-vehicle microphone, and processing the two signals to obtain a frequency response function FRF from a loudspeaker to the microphone;

step S3: exciting a plurality of speaker positions one by one;

step S4: obtaining a multi-order FRF function matrix, and writing the matrix into the active control unit as transfer functions S (z) and

the characteristic curve of (2).

Compared with the prior art, the invention has the following beneficial technical effects:

1. the method comprises the steps of jointly adopting a system architecture of front feedback and rear feedback to eliminate and inhibit low-frequency path noise (<300Hz sound component), wherein an acceleration signal at the position of a shaft head is used as a reference signal of a front feedback system, a noise signal obtained by a microphone in a vehicle is used as a residual signal of rear feedback, two paths of signals are input into an active control unit, the active control unit analyzes and processes the two paths of signals and outputs the signals to a loudspeaker to form sound waves with equal amplitude and opposite phase with the noise in the vehicle, and the noise inhibition is realized.

2. A transfer path frequency response function matrix obtained by means of experimental testing is introduced, and the problem of signal time delay caused by system characteristics is solved, so that the control precision and the noise reduction effect are improved, and the adaptability of the active control system to different vehicle types is greatly improved.

Drawings

FIG. 1 is a schematic diagram of an active control system according to the present invention;

FIG. 2 is a control block diagram of the active control system of the present invention;

fig. 3 is a flowchart of a control method in the present invention.

Description of the reference numerals

1. A microphone; 2. a speaker; 3. an active control unit; 4. an acceleration sensor.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a detailed description of the present invention will be given below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 1 and fig. 2, a road noise active control system based on a hybrid feedback architecture includes a plurality of acceleration sensors 4, a plurality of speakers 2, a plurality of microphones 1, and an active control unit 3;

the acceleration sensors 4 are respectively arranged at two ends of the front shaft and two ends of the rear shaft, and are used for acquiring a shaft head acceleration signal caused by road excitation and taking the shaft head acceleration signal as a front feedback signal x (n); the microphones 1 are respectively arranged at the head positions of drivers or members and are used for synchronously acquiring noise signals in the vehicle in real time as residual signals e (n); each door is provided with a loudspeaker 2, and a plurality of loudspeakers 2 are arranged at the front part of a cab of the commercial vehicle and are used for synchronously releasing sound waves with equal amplitude and opposite phase with road noise, wherein the signal is y (n).

Specifically, the active control unit 3 includes a data acquisition system, a DSP discrete signal processing module and a filter unit, the filter unit includes a front feedback adaptive filter a (z) and a rear feedback adaptive filter c (z), the active control unit 3 employs an FXLMS algorithm, and the algorithm minimizes the average potential energy of the residual signal e (n) by adjusting the weight vector matrices of a (z) and c (z) on line in real time.

The transfer function from the acceleration sensor 4 to the microphone 1 is p (z), the transfer function from the loudspeaker 2 to the microphone 1 is s (z), and due to the existence of the transfer function, the time delay problem of the signal occurs, so that the phase of the inverted signal and the phase of the noise signal are shifted, in order to solve the problem, the two signals are ensured to be in the same phase, and filters are respectively installed on the front feedback part and the rear feedback part and used for simulating the influence caused by the transfer path s (z).

The adaptive adjustment of the feedforward adaptive filter A (z) adopts an LMS algorithm, and the input signal is a feedforward reference signal

And residual signal e (n); the adaptive adjustment LMS algorithm of the post-feedback adaptive filter C (z) is realized by taking the input signal as a post-feedback reference signal

Of the residual signal e (n), wherein

As shown in fig. 3: a method for controlling noise actively based on a hybrid feedback architecture comprises the following steps:

step S1: the acceleration sensor 4 picks up the road surface excitation signal x (n) and outputs the road surface excitation signal x (n) to the active control unit 3;

step S2: the active control unit 3 intercepts signals in the frequency range of 0-300 HZ;

step S3: the LMS algorithm is used for convolving the signal sum and outputting the residual signal e (n) acquired by the microphone 1 to the front feedback part;

step S5: the LMS algorithm is used for convolving the post-feedback signal and the residual signal e (n) acquired by the microphone 1 and outputting the residual signal e (n) to the post-feedback part;

step S7: convolving a reference signal x (n) with an updated front feedback adaptive filter A (z), convolving a rear feedback signal with an updated rear feedback adaptive filter C (z), simultaneously superposing the two signals to form a signal y (n), and inputting the signal y (n) into a loudspeaker 2 to enable the loudspeaker 2 to emit an inverse sound wave;

Because the environment changes in real time during the running process of the vehicle, the steps from the step S1 to the step S8 are set to be completed in an iteration loop, the step length of one iteration is set to be 0.5S, when the average sound potential energy calculated in the step S6 reaches the minimum value, the system stops running and enters a convergence state, and after the road excitation changes, the system operates again, the iteration loop is carried out, the adjustment is carried out, so that the average sound potential energy reaches the minimum value, and a new convergence state is reached.

In order to solve the problem of signal delay caused by system characteristics, a transfer path frequency response function matrix obtained by means of experimental testing is introduced, and the method comprises the following steps of obtaining a transfer function P (z) between the acceleration sensor 4 and the microphone 1:

step S2: picking up a noise signal at the microphone 1 in the vehicle, processing the two signals, and obtaining a frequency response function FRF between a shaft head and the microphone 1;

step S4: a multi-order FRF function matrix is obtained and written into the active control unit 3 as the characteristic curve of the transfer function P (z).

The method further comprises the following steps of obtaining a transfer function S (z) between the loudspeaker 2 and the microphone 1:

step S1: a medium-low frequency volume sound source is arranged near the loudspeaker 2, and meanwhile, a sound signal of 0-300Hz is adopted for sweep frequency excitation;

step S2: picking up a noise signal at a microphone 1 in the vehicle, processing the two signals, and obtaining a frequency response function FRF from a loudspeaker 2 to the microphone 1;

step S3: exciting the positions of the plurality of loudspeakers 2 one by one;

step S4: a multi-level FRF function matrix is obtained and written into the active control unit 3 as a characteristic curve of the sum of the transfer functions S (z).

The embodiments given above are preferable examples for implementing the present invention, and the present invention is not limited to the above-described embodiments. Any non-essential addition and replacement made by the technical characteristics of the technical scheme of the invention by a person skilled in the art belong to the protection scope of the invention.

Claims

1. A kind of noise initiative control system based on mixed feedback framework, characterized by that: the system comprises a plurality of acceleration sensors (4), a plurality of loudspeakers (2), a plurality of microphones (1) and an active control unit (3);

the acceleration sensors (4) are respectively arranged at two ends of the front shaft and two ends of the rear shaft, and are used for acquiring a shaft head acceleration signal caused by road excitation to serve as a front feedback signal x (n);

the microphones (1) are respectively arranged at the head positions of drivers or members and are used for synchronously acquiring noise signals in the vehicle in real time as residual signals e (n);

each door is provided with a loudspeaker (2), and meanwhile, the front part of a cab of the commercial vehicle is provided with a plurality of loudspeakers (2) which are used for synchronously releasing sound waves with equal amplitude and opposite phase with road noise, and the signal is y (n).

2. The system of claim 1, wherein the system comprises: the active control unit (3) comprises a data acquisition system, a DSP discrete signal processing module and a filter unit, the filter unit comprises a front feedback adaptive filter A (z) and a rear feedback adaptive filter C (z), the active control unit (3) adopts an FXLMS algorithm, and the algorithm enables the average potential energy of a residual signal e (n) to be minimum by adjusting weight vector matrixes of A (z) and C (z) in real time on line.

3. The system of claim 2, wherein the system further comprises: the transfer function from the acceleration sensor (4) to the microphone (1) is P (z), the transfer function from the loudspeaker (2) to the microphone (1) is S (z), and filters are arranged on the front feedback part and the rear feedback part and used for simulating the influence brought by the transfer path S (z).

4. The system of claim 3, wherein the system comprises: the adaptive adjustment of the feedforward adaptive filter A (z) adopts an LMS algorithm, and the input signal is a feedforward reference signal

And residual signal e (n).

5. The system of claim 3, wherein the system comprises: the adaptive adjustment LMS algorithm of the post-feedback adaptive filter C (z) and the outputThe incoming signal being a post-feedback reference signal

Of the residual signal e (n), wherein

6. A method for actively controlling the noise based on a hybrid feedback architecture is characterized in that: comprises the following steps

Step S1: the acceleration sensor (4) picks up the road surface excitation signal x (n) and outputs the road surface excitation signal x (n) to the active control unit (3);

step S2: the active control unit (3) intercepts signals in the frequency range of 0-300 HZ;

step S3: the LMS algorithm is used for convolving the signal sum and outputting a residual signal e (n) acquired by the microphone (1) to a front feedback part;

step S5: the LMS algorithm is used for convolving the post-feedback signal and a residual signal e (n) acquired by the microphone (1) and outputting the residual signal e (n) to the post-feedback part;

step S7: convolving a reference signal x (n) with an updated front feedback adaptive filter A (z), convolving a rear feedback signal with an updated rear feedback adaptive filter C (z), simultaneously superposing the two signals to form a signal y (n), and inputting the signal y (n) into a loudspeaker (2) to enable the loudspeaker (2) to emit an inverse sound wave;

7. The method of claim 6, wherein the method comprises: and step S1 to step S8 are completed in an iteration loop, the step length of one iteration is set to 0.5S, when the average acoustic potential energy calculated in step S6 reaches the minimum value, the system stops operating and enters a convergence state, and when the road excitation changes, the system operates again, and the iteration loop is performed to adjust so that the average acoustic potential energy reaches the minimum value and reaches a new convergence state.

8. The method of claim 6, wherein the method comprises: the steps of obtaining the transfer function P (z) between the acceleration sensor (4) and the microphone (1) are as follows:

step S2: picking up a noise signal at a microphone (1) in the vehicle, processing the two signals, and obtaining a Frequency Response Function (FRF) between a shaft head and the microphone (1);

step S4: a multi-order FRF function matrix is obtained and written into the active control unit (3) as a characteristic curve of the transfer function P (z).

9. The method of claim 6, wherein the method comprises: the steps of obtaining the transfer function s (z) between the loudspeaker (2) and the microphone (1) are as follows:

step S1: a medium-low frequency volume sound source is arranged near the loudspeaker (2), and meanwhile, a sound signal of 0-300Hz is adopted for sweep frequency excitation;

step S2: picking up a noise signal at a microphone (1) in the vehicle, processing the two signals and obtaining a frequency response function FRF from a loudspeaker (2) to the microphone (1);

step S3: exciting the positions of a plurality of loudspeakers (2) one by one;

step S4: a multi-order FRF function matrix is obtained and written into the active control unit (3) as a characteristic curve of the sum of the transfer functions S (z).