CN111081213B

CN111081213B - New energy vehicle, active sound system thereof and active sound control method

Info

Publication number: CN111081213B
Application number: CN201811224327.1A
Authority: CN
Inventors: 赵永吉; 孙亚轩
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2018-10-19
Filing date: 2018-10-19
Publication date: 2022-12-09
Anticipated expiration: 2038-10-19
Also published as: CN111081213A

Abstract

The invention provides a new energy vehicle, an active sound system and an active sound control method thereof, aiming at solving the problems that in the prior art, only low-frequency noise or high-frequency noise is considered to be eliminated, the processing mode is not comprehensive enough, and the sound quality of the sound environment is still to be further improved. An active sound control method comprising the steps of: collecting noise signals in the new energy vehicle sound environment; generating a harmony construction signal according to the high-frequency noise signal; generating a phase noise-canceling signal with the same amplitude and the opposite phase of the low-frequency noise according to the low-frequency noise signal; playing the harmony construction signal, and playing noise reduction construction sound fused with high-frequency noise in the new energy vehicle sound environment to perform noise reduction processing on the high-frequency noise; and playing the phase noise-canceling signal, and playing the phase noise-canceling sound with the same amplitude as the phase noise in opposite phase with the low-frequency noise so as to cancel the low-frequency noise. The active sound control method provided by the invention enables drivers and passengers to have a very high-quality sound quality environment no matter under any working condition in the automobile.

Description

New energy vehicle, active sound system thereof and active sound control method

Technical Field

The invention relates to the field of new energy vehicles, in particular to the field of active sound control of new energy vehicles.

Background

From the viewpoint of environmental protection, all sounds affecting normal learning of people and working and resting are all called noises as "unnecessary sounds" of people in some occasions. Such as booming of a machine, motor sounds and whistling sounds of various vehicles, human noises, and various sudden sounds, are called noises. From a physical point of view, noise is the sound produced when the sounding body does random vibration. Noise pollution is a perceived public nuisance, which is related to subjective will of people and to the state of life of people, and thus it has characteristics different from other public hazards.

The noise generally comprises low-frequency noise, intermediate-frequency noise and high-frequency noise, wherein the noise with the frequency of 20 Hz-200 Hz is the low-frequency noise, and the noise with the frequency of 500 Hz-2 KHz becomes the intermediate-frequency noise; the noise having a frequency of 2kHz to 16kHz is a high-frequency noise. The ordinary speaking voice, walking voice and humming singing voice of people all belong to low-frequency noise, and the low-frequency noise has no harm to physical and mental health of people under ordinary conditions, and is favorable for improving the working efficiency under many conditions. High-frequency noise mainly comes from industrial machines (such as looms, lathes, air compressors, air picks, blowers, etc.), modern vehicles (such as automobiles, trains, motorcycles, tractors, airplanes, etc.), tweeters, noises at construction sites and malls, sports and entertainment places, etc. These high levels of noise can be harmful to the body, cause fatigue, create negative emotions, and even cause illness.

Taking a new energy vehicle as an example, motor noise emitted by a motor of the new energy vehicle is high-frequency noise, and the high-frequency noise of the motor is a noise comprehensive result and comprises mechanical noise, electromagnetic noise and air noise, wherein the frequency is from 1KHz to 12KHz or higher, and the high-frequency electromagnetic noise can bring strong discomfort to people. Wind noise, road noise and the like are low-frequency noise, and with the rapid development of the new energy industry, the noise of the new energy vehicle is relatively low compared with that of a traditional vehicle, but the high-frequency noise or the low-frequency noise of the new energy vehicle brings uncomfortable feeling to people. The noise treatment of the new energy vehicle is very necessary.

The existing method only considers eliminating low-frequency noise or high-frequency noise from a certain angle, does not solve various noise problems on the whole, has an incomplete processing mode, and has a space for further improving the sound quality of the sound environment.

Disclosure of Invention

The invention provides a new energy vehicle, an active sound system and an active sound control method thereof, aiming at solving the problems that in the prior art, only low-frequency noise or high-frequency noise is considered to be eliminated, the processing mode is not comprehensive enough, and the sound quality of the sound environment is still to be further improved.

The invention provides an active sound control method on one hand, which comprises the following steps:

collecting noise signals in the new energy vehicle sound environment; the noise signal comprises a high-frequency noise signal and a low-frequency noise signal;

acquiring the high-frequency noise signal, and generating a harmony construction signal according to the high-frequency noise signal; acquiring the low-frequency noise signal, and generating a phase de-noising signal which is opposite in phase and has the same amplitude as the low-frequency noise according to the low-frequency noise signal;

playing the harmony construction signal, and playing noise reduction construction sound fused with high-frequency noise in the new energy vehicle sound environment to perform noise reduction processing on the high-frequency noise; and playing the phase noise-canceling signal, and playing phase noise-canceling sound with the same amplitude as the phase noise in opposite phase with the low-frequency noise so as to cancel the low-frequency noise.

The active sound control method provided by the invention can comprehensively solve the noise problem of the existing new energy vehicle, and according to the difference of noise frequencies, for low-frequency noise such as road noise, tire noise and the like, the opposite-phase equal-amplitude phase noise elimination sound is played for noise elimination, and for high-frequency noise such as a motor and the like, the noise reduction structure sound fused with the high-frequency noise is played for noise reduction of the high-frequency noise, so that the low-frequency noise in the vehicle is eliminated, and meanwhile, the high-frequency noise is subjected to noise reduction, so that drivers and passengers have a high-quality sound quality environment no matter what working conditions are in the vehicle.

Further, the step of collecting the noise signals in the acoustic environment of the new energy vehicle specifically comprises the following steps:

acquiring operation parameters of the new energy vehicle, and acquiring the frequency of a high-frequency noise signal associated with the operation parameters according to the operation parameters; the operation parameters at least comprise the motor rotating speed of the new energy vehicle, and the motor rotating speed and the frequency of the high-frequency noise signal are in a corresponding relation;

the step of acquiring the high-frequency noise signal and generating a harmony construction signal according to the high-frequency noise signal specifically includes the following steps:

acquiring a harmony construction signal corresponding to the in-vehicle environmental noise signal by calling a preset construction sound database according to the frequency of the high-frequency noise signal;

alternatively, a harmonic constructed signal is generated by a sound construction function according to the frequency of the high frequency noise signal.

According to the preferable generation method of the harmony structural signal, the operation parameters of the new energy vehicle are collected through the CAN bus, data are read through the CAN bus to obtain the corresponding harmony structural signal, then the noise reduction structural sound is controlled to be output, and the noise reduction processing of the high-frequency noise in the environment in the vehicle CAN be realized through the fusion of the noise reduction structural sound and the high-frequency noise in the vehicle. The method is easy to implement, simple to operate and less limited. In addition, the method utilizes the CAN bus to obtain the required data, so that the data is objective, accurate and more visual.

collecting acoustic environment noise in an acoustic environment of the new energy vehicle, wherein the acoustic environment noise comprises high-frequency motor noise and low-frequency non-motor noise;

acquiring the frequency of the non-motor noise and the sound pressure level of the motor noise; acquiring operation parameters of the new energy vehicle, and acquiring the frequency of a motor noise signal associated with the operation parameters according to the operation parameters; the operation parameters at least comprise the motor rotating speed of the new energy vehicle;

the step of acquiring the high-frequency noise signal and generating a harmonic structure signal according to the high-frequency noise signal specifically includes the following steps:

generating harmony construction signals according to the frequency of non-motor noise in the collected sound environment noise and the frequency of the acquired motor noise signals;

the step of playing the harmony construction signal and playing the noise reduction construction sound fused with the high-frequency noise in the new energy vehicle sound environment so as to perform noise reduction processing on the high-frequency noise specifically comprises the following steps:

converting the harmony construction signal into a noise reduction audio signal, and adjusting the sound pressure level of the noise reduction audio signal according to the sound pressure level of the motor noise;

and inputting the noise reduction audio signal into a sound playing device for playing so as to output noise reduction structure sound and perform noise reduction processing on high-frequency noise of the new energy vehicle.

The above-described preferred high-frequency noise reduction scheme that provides, it is the frequency of non-motor noise and the sound pressure level of motor noise in the acoustic environment that gathers in real time. Acquiring the operating parameters of the new energy vehicle, the frequency of non-motor noise and the sound pressure level of the motor noise; further acquiring the frequency of a motor noise signal corresponding to the operation parameter, and simultaneously generating a harmony construction signal according to the acquired frequency of non-motor noise in the acoustic environment noise and the acquired frequency of the motor noise signal; converting the harmony construction signal into a noise reduction audio signal, and adjusting the sound pressure level of the noise reduction audio signal according to the sound pressure level of the motor noise; and then inputting the noise reduction audio signal into a sound playing device for playing so as to output noise reduction structure sound. Therefore, the noise reduction structure sound played by the sound playing device is fused with the sound environment noise, the generated harmony structure signal not only considers the frequency of the motor noise signal, but also comprehensively considers the sound pressure level of other non-motor noises and motor noises in the sound environment, and the problem of sound environment quality reduction caused by the fact that the structure signal generated by only relying on the frequency of one motor noise signal is easy to form a new enhanced noise signal with other non-motor noise components due to overlapping, interference and the like is avoided, and the sound environment quality is better improved. The improved scheme can effectively solve the problem of high-frequency noise caused by the increase of the vehicle speed, and the method is easy to implement, simple and easy to operate.

Further, the "generating a harmonic structure signal according to the high-frequency noise signal" specifically includes the following steps:

constructing and generating the harmony construction signal according to the frequency of the high-frequency noise signal, wherein the harmony construction signal is a harmony masking signal;

the harmony masking signal comprises a harmony signal and a masking signal; the harmonic signal is a subharmonic of the high frequency noise signal.

Preferably, the active sound control method is provided, in which a subharmonic signal of the high-frequency noise signal is constructed as a harmonic signal, and a masking signal having a frequency close to that of the high-frequency noise signal is added to the harmonic signal to mask the high-frequency noise signal, so that the ratio of the high-frequency component of the noise in the entire frequency domain is reduced, and the amount of the high-frequency component reflects the degree of the fidget, so that the degree of fidget is reduced. Also, the addition of the masking signal can obscure the high frequency noise signal and reduce the level of fidget. Thus, the sound quality of the sound environment can be further improved. Meanwhile, the method is simple and easy to operate and low in cost.

Further, the method also comprises the following steps:

judging whether to trigger the warning tone playing condition, and when the warning tone playing condition is triggered, entering the following steps:

collecting the speed of the new energy vehicle;

comparing the vehicle speed with a preset threshold value; and when the vehicle speed is greater than or equal to the preset threshold value, playing a first prompt tone outside the vehicle.

After the speed of a motor vehicle exceeded and predetermine the threshold value, can be used to broadcast the first prompt tone that relatively accords with real driving situation, warn the personnel outside the car.

Further, the method also comprises the following steps:

and when the vehicle speed is less than the preset threshold value, playing a second prompt tone outside the vehicle and/or inside the vehicle. The second warning sound can be used for generating a warning sound outside the vehicle to warn pedestrians on the road. The warning sound may be a steady engine sound or other sound that may attract the attention of a pedestrian or the like. Or the second prompt sound can be played to the interior of the vehicle, so that the condition that the attention of a driver is not concentrated due to the fact that the interior of the vehicle is too quiet is prevented.

The invention provides an active sound system in a second aspect, which comprises a noise acquisition module, an active sound controller and a sound playing device, wherein the noise acquisition module is used for acquiring noise;

the noise acquisition module is used for acquiring noise signals in a new energy vehicle sound environment, wherein the noise signals comprise high-frequency noise signals and low-frequency noise signals;

the active sound controller is used for acquiring the high-frequency noise signal and generating a harmony construction signal according to the high-frequency noise signal; acquiring the low-frequency noise signal, and generating a phase denoising signal with the phase opposite to the low-frequency noise and the same amplitude as the low-frequency noise according to the low-frequency noise signal;

the sound playing device is used for playing the harmony construction signal and playing noise reduction construction sound fused with high-frequency noise in the new energy vehicle sound environment so as to perform noise reduction processing on the high-frequency noise; and playing the phase noise-canceling signal, and playing phase noise-canceling sound with the same amplitude as the phase noise in opposite phase with the low-frequency noise so as to cancel the low-frequency noise.

The active sound system provided by the invention can comprehensively solve the noise problem in the existing new energy vehicle, the active sound controller generates phase noise elimination signals for low-frequency noise such as road noise, tire noise and the like according to the difference of noise frequencies, the sound playing device plays the phase noise elimination sound with opposite phase and equal amplitude for noise elimination processing, and the sound playing device plays the noise reduction structure sound which is fused with the high-frequency noise for noise reduction processing of the high-frequency noise such as a motor and the like, so that the low-frequency noise in the vehicle is eliminated, and the high-frequency noise is subjected to noise reduction processing at the same time, so that drivers and passengers have a high-quality sound quality environment no matter under any working condition in the vehicle.

Furthermore, the noise acquisition module specifically acquires noise signals through a microphone arranged in an acoustic environment or acquires working condition information of a vehicle through a sensor to acquire the noise signals, and acquires the noise signals by reading data information transmitted by a CAN bus of the new energy vehicle

Further, the active acoustic controller comprises the following modules:

the harmony structural signal generating module is used for acquiring the high-frequency noise signal and generating a harmony structural signal according to the high-frequency noise signal;

and the phase noise-canceling signal generating module is used for acquiring the low-frequency noise signal and generating a phase noise-canceling signal with the same amplitude as the low-frequency noise in an opposite phase according to the low-frequency noise signal.

Further, the sound playing device comprises a first playing device and a second playing device;

the first playing device is used for playing the harmony construction signal, and playing noise reduction construction sound fused with high-frequency noise in the new energy vehicle sound environment so as to perform noise reduction processing on the high-frequency noise;

and the second playing device is used for playing the phase de-noising signal and playing phase de-noising sound which is opposite in phase and has the same amplitude with the low-frequency noise so as to eliminate the low-frequency noise.

Further, still include warning sound play module, warning sound play module includes following unit:

the condition judging unit is used for judging whether to trigger the warning sound playing condition or not;

the vehicle speed obtaining unit is used for obtaining the vehicle speed of the new energy vehicle;

the third playing device is used for comparing the vehicle speed with a preset threshold value; and when the vehicle speed is greater than or equal to the preset threshold value, playing a first prompt tone outside the vehicle. This warning sound playing module can be used to play the first warning sound that relatively accords with real driving situation after the speed of a motor vehicle surpasses the preset threshold value, warns the personnel outside the car.

Further, the third playing device is further configured to play a second prompt tone to the outside of the vehicle and/or the inside of the vehicle when the vehicle speed is less than the preset threshold value. This warning sound playing module can be used to play the first warning sound that relatively accords with real driving situation after the speed of a motor vehicle surpasses the preset threshold value, warns the personnel outside the car. When the speed of a motor vehicle is less than preset threshold value, broadcast the second warning sound, be used for producing a warning sound outside the car and warn the pedestrian on the road. The warning sound may be a steady engine sound or other sound that may attract the attention of a pedestrian or the like. Or the second prompt tone can be played to the interior of the vehicle, so that the situation that the driver is distracted due to too quiet interior of the vehicle is prevented.

The invention provides a new energy vehicle, which comprises the active sound system.

The active sound controller generates phase noise elimination signals for low-frequency noises such as road noises and tire noises according to different noise frequencies, plays the phase noise elimination sounds with opposite phases and equal amplitudes through the sound playing device for noise elimination, generates noise reduction structure sounds for high-frequency noises such as motors, and plays the noise reduction structure sounds fused with the high-frequency noises through the sound playing device for noise reduction of the high-frequency noises so as to eliminate the low-frequency noises in the vehicle and simultaneously perform noise reduction on the high-frequency noises, so that drivers and passengers in the vehicle have a high-quality sound environment no matter under any working condition.

Drawings

FIG. 1 is a flow chart of an active sound control method provided in an embodiment of the present invention;

FIG. 2 is a detailed flowchart of step S1 provided in an embodiment of the present invention;

FIG. 3 is a flowchart illustrating the step S2 provided in the embodiment of the present invention;

FIG. 4 is a flow chart of a preferred active sound control method provided in an embodiment of the present invention;

FIG. 5 is a detailed flowchart of step S4 provided in an embodiment of the present invention;

FIG. 6 is a schematic diagram of the harmonic construction signal generation principle provided in the specific embodiment of the present invention;

FIG. 7 is a schematic diagram of the frequency spectrum of a constructed masking signal and harmonic signal provided in an embodiment of the present invention;

FIG. 8 is a schematic frequency spectrum diagram of another configuration masking and harmonic signals provided in embodiments of the present invention;

FIG. 9 is a block diagram of an active sound system provided in an embodiment of the present invention;

FIG. 10 is a block diagram of a further preferred active sound system configuration provided in accordance with an embodiment of the present invention;

FIG. 11 is a block diagram of an active acoustic controller provided in an embodiment of the present invention;

fig. 12 is a block diagram of a sound playing apparatus according to an embodiment of the present invention;

fig. 13 is a block diagram of a warning tone playing module according to an embodiment of the present invention;

fig. 14 is a block diagram of a new energy vehicle according to an embodiment of the present invention.

Wherein the content of the first and second substances,

1000. a new energy vehicle;

100. an active sound system;

1. a noise acquisition module;

2. an active acoustic controller; 21. a harmony construction signal generation module; 22. a phase noise-eliminating signal generating module;

3. a sound playing device; 31. a first playback device; 32. a second playback device;

4. a warning sound playing module; 41. a condition judgment unit; 42. a vehicle speed acquisition unit; 43. and a third playing device.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In order to further understand the present invention, the high frequency noise and the low frequency noise, and the principle of denoising or eliminating the high frequency noise and the low frequency noise in the present invention will be explained first.

The principle of the present invention for canceling low frequency noise is explained as follows.

The technology for eliminating low-frequency noise is called phase cancellation technology (ANC technology for short), that is, a sound signal with a phase opposite to that of a target noise signal is generated aiming at the target noise signal, so as to cancel the original noise signal. In the past use case, the ANC technology is mainly applied to the earphone end to eliminate the low-frequency noise. There are few cases of low frequency noise transmitted to the cab from the engine compartment, as used on conventional engine vehicles. ANC technology or similar technology has not been heard in new energy vehicles for noise reduction applications, mainly due to the lack of engines, which are perceived as being unnecessary for low frequency noise processing. It is now increasingly noticed that although there is no engine, during driving, tire noise and wind noise become the main low frequency noise sources, and this part of the noise is transmitted into the cab, which not only increases the sound pressure level in the vehicle, but also increases the irritation level in the vehicle. So for this part of the noise we do: the main path for the transfer of the tire noise and wind noise into the vehicle is first defined, and a feedback microphone is arranged on the main transfer path. The ANC module is connected with the CAN bus (in the early preparation process, the relation between the tire rotating speed/the vehicle speed and the noise frequency needs to be determined), when the vehicle speed reaches the target vehicle speed, the phase is started to eliminate and reduce noise, and the phase and the step length are adjusted by using the feedback microphone, so that the purpose of offsetting the noise is achieved.

The following explains the principle of the present invention on how to construct the generation of harmonic construction signals and play them for noise reduction, so that the skilled person can more easily understand the present invention.

The generation and construction sound playing to reduce the noise of the high-frequency motor noise mainly utilizes the related knowledge of psychoacoustics and music acoustics. In psychoacoustics, the human ear is not easy to accept high-frequency signals, and especially narrow-band high-frequency signals can greatly cause the dysphoria of people and even cause physiological discomfort (carsickness and nausea). However, this high frequency noise signal is very acceptable when combined with other frequency components to form a new sound signal, an interesting example being the high pitch of a singer, which we prefer, but which is difficult to accept as a "squeak" when a metal object is drawn across the glass, although the center frequencies of the two may be quite different.

As shown in fig. 6, the upper dotted line frame shows the principle of music composition in musical acoustics, in which the sound we hear (including noise as well) is composed of two parts, fundamental wave and harmonic wave (harmonic), and the frequency of harmonic wave (harmonic frequency for the sake of distinction) is usually integral multiple of the frequency component of fundamental wave (fundamental frequency for the sake of distinction), for example, if the fundamental frequency is XHz, the harmonic frequency is AXHz, bz, CXHz, dxhhz, etc., where a, B, C, D are all positive integers, that is, the harmonic frequency is integral multiple of the fundamental frequency. The fundamental frequency determines the pitch, the harmonic frequencies determine the timbre, which determines the "soundless" or "nice" sound (of course, they are all the result of interactions, not so simple single correspondences, and are used here for better understanding). Thus, it can be explained that the high pitch of the singer and the "squeak" sound of the metal object across the glass are different in the overtones, because the subjective feeling is different from the natural feeling, although the center frequencies are close.

In a new energy vehicle, the frequency of motor noise is generally high, if the harmonic component of the motor noise is constructed completely according to the principle of musical acoustics, subjective feeling is improved, but the noise is increased due to the increase of high-frequency components, and the purpose of improving the quality of environmental sound cannot be achieved. Therefore, the reverse thinking is that the construction mechanism is still the relevant principle of music acoustics by adding the fractional harmonic (called the fractional harmonic for short) component of the high-frequency signal. The effect of adding fractional harmonics and the effect of adding harmonics in subjective feeling are the same, the sound quality can be improved, and the explanations of the fractional harmonics and the harmonic waves in a physical mechanism are the same, namely, the probability of superposition of two signals is the same, for example, the fundamental frequency is 5000Hz, the harmonic frequency is 10000Hz, the harmonic frequency is superposed with the fundamental frequency once per two times of vibration, and the frequency ratio of the harmonic frequency to the fundamental frequency is 2; the fundamental frequency is 5000Hz, the subharmonic component is 2500Hz, the fundamental frequency coincides with the subharmonic once per two times of vibration, and the frequency ratio of the fundamental frequency to the harmonic frequency is 2; the two are identical. In psychoacoustics, when sub-harmonics of a motor high-frequency signal are added, the ratio of high-frequency components in the whole frequency domain is reduced, and the amount of the high-frequency components reflects the size of the dysphoria, so the dysphoria is reduced.

Based on the principle, the invention provides an active sound system and a control method for processing low-frequency noise and high-frequency noise on a new energy vehicle. Hereinafter, the present invention will be explained in detail with reference to examples.

A first embodiment of the present invention will specifically explain an active sound control method provided by the present invention, as shown in fig. 1, including the following steps:

s1, noise signal acquisition: collecting noise signals in the new energy vehicle sound environment; the noise signal comprises a high-frequency noise signal and a low-frequency noise signal;

s2, processing: acquiring the high-frequency noise signal, and generating a harmony construction signal according to the high-frequency noise signal; acquiring the low-frequency noise signal, and generating a phase denoising signal with the phase opposite to the low-frequency noise and the same amplitude as the low-frequency noise according to the low-frequency noise signal;

s3, sound playing: playing the harmony construction signal, and playing noise reduction construction sound fused with high-frequency noise in the new energy vehicle sound environment to perform noise reduction processing on the high-frequency noise; and playing the phase noise-canceling signal, and playing phase noise-canceling sound with the same amplitude as the phase noise in opposite phase with the low-frequency noise so as to cancel the low-frequency noise.

In step S1, as shown in fig. 2, the method specifically includes the following steps:

step S1A, a high-frequency noise acquisition step: collecting high-frequency noise signals in an acoustic environment;

step S1B, low-frequency noise acquisition: low frequency noise signals in an acoustic environment are collected.

The steps S1A and S1B are not in sequence.

The acoustic environment refers to a system formed by all sounds in a certain area, and the acoustic environment of the new energy vehicle refers to the internal environment of the new energy vehicle, specifically, in this example, the space where a driver and a passenger are located, such as a cab (or a passenger cab, the effect is also equivalent).

By noise in the acoustic environment is meant noise that is felt by the driver or passengers in the acoustic environment, which on the one hand comprises high frequency noise originating from the motor, also referred to as motor noise. Through research on high-frequency motor noise of a new energy vehicle, the fact that when the rotating speed of a motor reaches a certain value, howling can be generated is found, the frequency of the howling can be generally divided into two types, one type is constant in frequency and is called constant-frequency howling, and the other type is variable-frequency and is called variable-frequency howling. Both of the above two types of howling are high-frequency motor noise. On the other hand, other low-frequency noise (non-motor noise, such as road noise, tire noise, deconstructed vibration noise, etc., which is relatively low in frequency) is also included.

Meanwhile, the noise also belongs to sound, and parameters representing the noise of the sound environment also comprise frequency, sound pressure level and the like.

In this example, the high-frequency noise signal is collected in step S1A, and the purpose of the high-frequency noise signal is to generate high-frequency noise processing for processing the high-frequency noise. As will be explained in detail later.

Regarding how to specifically acquire the low-frequency noise signal in step S1B, those skilled in the art can understand many common knowledge, and only briefly describe here. For example, low-frequency noise such as road noise and fetal noise is collected by a microphone and converted into an analog signal (low-frequency noise signal). The low frequency noise signal has parameters such as frequency and sound pressure level. And the acquisition of the operation parameters CAN also be realized by reading data information transmitted by a CAN bus of the new energy vehicle. Optionally, the operation parameters of the new energy vehicle may further include a vehicle speed, an accelerator opening degree, and the like of the new energy vehicle. The operation parameters at least comprise the motor rotating speed of the new energy vehicle, and the motor rotating speed and the frequency of the environmental noise signals in the vehicle are in a corresponding relation. The parameters of the low frequency noise signal are then obtained from the operating parameters.

The parameters of the acoustic environment noise collected in the step S1 CAN be transmitted through a CAN bus, and similarly, the collection of the frequency of the non-motor noise and the sound pressure level of the motor noise CAN also be realized by reading data information transmitted through the CAN bus of the new energy vehicle.

As to how the high frequency noise signal is acquired in detail, the explanation is as follows.

The invention collects high-frequency noise signals, can collect noise through a microphone, and identifies the frequency, the sound pressure level characteristic parameters and the like of the high-frequency noise.

In the embodiment of the invention, as a preferable mode, the acquisition of the operation parameters CAN be realized by reading data information transmitted by a CAN bus of the new energy vehicle. Optionally, the operation parameters of the new energy vehicle may further include a vehicle speed, an accelerator opening degree, and the like of the new energy vehicle. The operation parameters at least comprise the motor rotating speed of the new energy vehicle, and the motor rotating speed corresponds to the frequency of the environmental noise signals in the vehicle.

Specifically, the relationship between the motor rotation speed and the frequency of the in-vehicle environmental noise signal may be stored in advance. When the operation parameters are collected, the CAN bus system of the new energy vehicle CAN be accessed, and the operation parameters such as the motor rotating speed, the vehicle speed, the accelerator opening degree and the like CAN be obtained by reading data transmitted by the CAN bus of the new energy vehicle. And then a pre-stored relation comparison table or relation database or relation curve between the rotating speed of the motor and the frequency of the in-vehicle environmental noise signal CAN be obtained through the CAN bus, and the corresponding in-vehicle environmental noise frequency CAN be obtained according to the rotating speed of the motor.

In the embodiment of the invention, the acquisition of the operation parameters CAN be realized by reading the data information transmitted by the CAN bus of the new energy vehicle. Optionally, the operation parameters of the new energy vehicle may further include a vehicle speed, an accelerator opening degree, and the like of the new energy vehicle.

Specifically, the relationship between the motor rotation speed and the frequency of its high-frequency noise signal may be stored in advance. When the operation parameters are collected, the CAN bus of the new energy vehicle CAN be accessed, and the operation parameters such as the rotating speed of the motor, the speed of the vehicle, the opening degree of the accelerator and the like CAN be obtained by reading data transmitted by the CAN bus of the new energy vehicle. And then the relation between the prestored motor rotating speed and the frequency of the motor noise signal CAN be obtained through the CAN bus, and the corresponding frequency of the motor noise signal CAN be obtained according to the motor rotating speed.

Specifically, the operation parameter is taken as the motor rotation speed as an example for explanation. In order to obtain the relationship between the motor rotating speed and the frequency of the motor noise signal, firstly, under different working conditions, the motor rotating speed of the new energy vehicle and the motor noise signal corresponding to the motor rotating speed are collected; then, performing frequency domain analysis on the collected motor noise signal through a spectrum analyzer to obtain frequency spectrum characteristic information of the motor noise signal, such as frequency and sound pressure level; and then the corresponding relation between the motor rotating speed and the frequency and sound pressure level of the motor noise signal can be obtained.

As shown in fig. 3, step S2 can be divided into the following two steps:

S2A, a harmony structural signal generating step: acquiring the high-frequency noise signal, and generating a harmony construction signal according to the high-frequency noise signal;

the preset structure sound database CAN be established in advance and stored, and after the frequency of the in-vehicle environment noise signal is obtained, the preset structure sound database CAN be called through the CAN bus, so that the harmony structure signal corresponding to the in-vehicle environment noise signal CAN be obtained. Alternatively, the harmonic structure signal is generated by a generating function according to the frequency of the high-frequency noise signal. The way in which the harmonic constructed signals are generated will be described below by various cases.

S2B, generating a phase noise-eliminating signal: acquiring the low-frequency noise signal, and generating a phase denoising signal with the phase opposite to the low-frequency noise and the same amplitude as the low-frequency noise according to the low-frequency noise signal;

in step S2B, a microphone is specifically disposed on a path along which low-frequency noise propagates in the vehicle to collect a noise sample, and a noise signal is transmitted to the control circuit, analyzed and processed by the system, and then calculated in real time. And generating a phase noise elimination signal with the same amplitude and phase opposite to the low-frequency noise signal.

The active sound control method provided by the embodiment can comprehensively solve the noise problem of the existing new energy vehicle, and according to the difference of noise frequencies, for low-frequency noise such as road noise, tire noise and the like, the noise reduction processing is carried out by playing reversed-phase equal-amplitude phase noise reduction sound, and for high-frequency noise such as a motor and the like, the noise reduction processing is carried out by playing noise reduction structure sound fused with high-frequency noise so as to eliminate the low-frequency noise in the vehicle, and simultaneously, the noise reduction processing is carried out on the high-frequency noise, so that drivers and passengers have high-quality sound quality environment no matter what working conditions are in the vehicle.

With regard to how the high frequency noise signal is specifically acquired and the harmonic construction signal is generated based on the high frequency noise signal. The following further explains the preferred embodiments.

As a preferred implementation manner, in the second embodiment, the main steps are the same as those in the first embodiment, and only some of the steps are further optimized, and preferably, the step S1A specifically includes the following steps:

the step S2A specifically includes the steps of:

acquiring a harmony construction signal corresponding to the environment noise signal in the vehicle by calling a preset construction sound database according to the frequency of the high-frequency noise signal;

According to the generating method of the harmony structural signal, the operation parameters of the new energy vehicle are collected through the CAN bus, data are read through the CAN bus to obtain the corresponding harmony structural signal, then the noise reduction structural sound is controlled to be output, and the noise reduction processing of the high-frequency noise in the environment in the vehicle CAN be realized through the fusion of the noise reduction structural sound and the high-frequency noise in the vehicle. The method is easy to implement, simple to operate and less limited. In addition, the method acquires the required data by utilizing the CAN bus, so that the data is objective, accurate and more visual.

The step of acquiring the harmony structure signal corresponding to the in-vehicle environment noise signal by calling a preset structure sound database for the frequency of the high-frequency noise signal specifically includes the following steps:

judging the frequency band of the environment noise signal in the vehicle according to the frequency of the environment noise signal in the vehicle; and calling a preset constructed sound database according to the frequency band of the in-vehicle environmental noise signal to acquire a harmony constructed signal corresponding to the frequency band of the in-vehicle environmental noise signal, wherein the preset constructed sound database stores a plurality of constructed sound samples, each constructed sound sample corresponds to one noise frequency band and comprises the harmony constructed signal corresponding to the noise frequency band.

It is necessary to construct a preset structure sound database in advance. In this example, the preset construction process of constructing the sound database includes:

firstly, collecting the running parameters of the new energy vehicle and the noise of the environment in the vehicle under different working conditions.

Preferably, the noise generated by the motor can be detected to realize the collection of the noise of the environment in the vehicle. It can be understood that when the new energy vehicle is running, the motor of the new energy vehicle generates noise, the noise comprises mechanical noise, electromagnetic noise, air noise and the like, the frequency is from 1KHz to 12KHz or higher, and the high-frequency noise can bring strong discomfort to people. Therefore, it is very necessary to treat such high frequency noise.

Specifically, the noise generated by the motor can be collected in real time through a sound signal receiver (such as a microphone and the like) and/or a rotation speed sensor. For a motor with a relatively constant load, noise can be collected only by using a rotating speed sensor; for the motor with larger load change, the noise can be simultaneously collected through the rotating speed sensor and the sound signal receiver so as to improve the collection precision of the noise.

It should be noted that, the noise signal of the environment in the vehicle can be directly collected at the motor end, so that the integrity of the noise generated by the motor can be ensured, and uncertain factors such as attenuation generated in the propagation process of the noise can be eliminated.

Secondly, performing spectrum analysis on the noise of the environment in the vehicle to acquire noise spectrum characteristic information associated with the operation parameters, and establishing a corresponding relation between the operation parameters and the noise of the environment in the vehicle according to the noise spectrum characteristic information.

Specifically, the operation parameter is taken as the motor rotation speed as an example for explanation. Under different working conditions, the motor rotating speed of the new energy vehicle and the in-vehicle environmental noise corresponding to the motor rotating speed can be acquired; then, frequency domain analysis can be carried out on the collected noise of the environment in the vehicle to obtain the frequency spectrum characteristic information of the noise of the environment in the vehicle, such as frequency and sound pressure level; and then the corresponding relation between the rotating speed of the motor and the frequency and the sound pressure level of the noise of the environment in the vehicle can be obtained.

Thirdly, according to the noise spectrum characteristic information, frequency band division is carried out on the noise of the vehicle environment under different working conditions so as to obtain noise signals of multiple frequency bands.

Specifically, the noise frequency of the environment inside the vehicle may be divided into a high frequency, a low frequency, a constant frequency, a variable frequency, and the like according to the rotational speed of the motor. It can be understood that when the rotating speed of the motor is higher, the high-frequency noise can be correspondingly generated; when the rotating speed of the motor is low, the low-frequency noise can be correspondingly generated; the change of the rotating speed of the motor is small, namely when the rotating speed is basically constant, the corresponding constant frequency noise can be obtained; the rotation speed of the motor is gradually increased, namely acceleration exists, and when the acceleration is larger than a certain value, the corresponding frequency conversion noise can be generated.

The frequency division of the noise in the vehicle interior environment is performed to save workload when frequency construction is performed. For example, a high-frequency component in the in-vehicle ambient noise has a relatively strong sharp feeling, and a low-frequency component can be appropriately added in the frequency structure.

For example, when the frequency of the environmental noise in the vehicle is high frequency, such as 3000-6000Hz, 600-1000Hz sound may be constructed to be added to the high frequency noise.

Fourth, a noise signal of any frequency band is selected, and frequency-constructed on the noise signal of the selected frequency band according to a musical acoustic or psychoacoustic principle to generate a plurality of sum sound construction signals.

Specifically, for any frequency band of noise signals, the frequency of the frequency band of noise signals may be constructed by sound processing software (such as LEA software) according to the musical acoustics or psychoacoustics principle to generate a plurality of sum sound construction signals.

Fifthly, the noise signal of the selected frequency band is respectively synthesized with each harmony construction signal to generate and output a plurality of synthesized sound samples.

Wherein the frequency band to which the frequency of each synthesized sound sample belongs comprises the selected frequency band. For example, for a noise signal in a frequency band of 4000 to 5000Hz, a frequency structure is performed to obtain a low-frequency signal in a frequency band of 400 to 500Hz, and the frequency band to which the frequency of the synthesized sound sample obtained by synthesizing the noise signal and the frequency sample belongs may be 400 to 6000Hz, and thus, the frequency band of 400 to 6000Hz includes the frequency band of 4000 to 5000 Hz. Thus, the frequency of the noise signal of the selected frequency band can be compensated by the harmonic constructed signal, i.e. the frequency coverage of the synthesized sound sample is wide.

It should be noted that, in the embodiment of the present invention, the sound pressure level of the harmony construction signal is equal to or less than the sound pressure level of the noise signal of the selected frequency band, and thus, after the harmony construction signal is synthesized with the noise signal of the selected frequency band, the sound pressure level of the harmony construction signal has a small influence on the sound pressure level of the generated synthesized sound sample. It will be appreciated that the greater the difference between the sound pressure level of the harmony construction signal and before the sound pressure level of the noise signal of the selected frequency band, the less the sound pressure level of the harmony construction signal has an effect on the sound pressure level of the generated synthesized sound sample when the sound pressure level of the harmony construction signal is less than the sound pressure level of the noise signal of the selected frequency band.

And sixthly, scoring each synthetic sound sample according to a preset evaluation method, and acquiring a constructed sound sample corresponding to the noise signal of the selected frequency band according to the scoring result of each synthetic sound sample.

The preset evaluation method may include: 1) Determining an evaluator, wherein the evaluator is required to have normal hearing and can be a common worker, and the number of persons can be required to be more than 10; 2) The scoring standard can be a percentage system, and five-grade evaluation standards are adopted, such as, excellent: very pleasant (e.g., sounds pleasant, calm, pleasant) (80-100 points), good: pleasing to the ear (60-80 points), middle: generally 40-60 points), the difference: inaudibility (20-40 points), poor: very difficult to hear (e.g., sound uncomfortable, restless, irritated, etc.) (0-20 points), i.e., the rater may perform a percentile rating based on a ranking rating; 3) The audition condition can be evaluated in a quieter indoor environment.

For example, 10 adults each of a male and a female constitute an evaluator, and each synthesized sound sample corresponding to the selected frequency band is played in a quieter indoor environment, and each synthesized sound sample can be played 3 times. After 3 times of playing, 20 evaluators score the sound, and after the scoring is completed, the scoring result is subjected to mathematical statistics to select the synthetic sound sample with the highest score (e.g. the highest average score), and the structural sound sample corresponding to the synthetic sound sample is taken as the structural sound sample corresponding to the noise signal of the selected frequency band. Similarly, the constructed sound samples corresponding to the noise signals of each frequency band may be obtained, and the set of all the constructed sound samples is the preset constructed sound database.

Alternatively, it may also generate the harmonic constructed signal by a functional expression as follows: y = Ky + b, and Y = asin (2 × pi × a × f × t); where K denotes the slope of the frequency, a denotes the amplitude of the harmonic structure signal, a denotes the harmonic coefficient, f denotes the frequency of the harmonic structure signal, and t denotes time.

As a preferred implementation manner, the third embodiment has the same main steps as the second embodiment, and only some of the steps are optimized, and specifically includes the following steps:

the step S1 specifically includes the following steps: collecting acoustic environment noise in an acoustic environment of the new energy vehicle, wherein the acoustic environment noise comprises high-frequency motor noise and low-frequency non-motor noise;

the step S2A in the step S2 comprises the following steps:

in the step S3, "playing the harmony construction signal, and playing the noise reduction construction sound fused with the high-frequency noise in the new energy vehicle sound environment to perform noise reduction processing on the high-frequency noise" specifically includes the following steps:

firstly, converting the harmony construction signal into a noise reduction audio signal, and adjusting the sound pressure level of the noise reduction audio signal according to the sound pressure level of the motor noise;

and secondly, inputting the noise reduction audio signal into a sound playing device for playing so as to output noise reduction structure sound and perform noise reduction processing on high-frequency noise of the new energy vehicle.

This preferred third embodiment is explained in further detail below.

When a subharmonic signal is added, if the sound pressure level is too large, it may also become a new noise introduced, and therefore, in order for the subharmonic to function as a fusion with the high-frequency motor noise for the purpose of noise reduction, it is necessary to control the sound pressure level of the subharmonic within a suitable range. The sound pressure level (sound pressure level) is an index for representing the magnitude of sound pressure, and the sound pressure is the change of atmospheric pressure after being disturbed by sound waves, namely the residual pressure of the atmospheric pressure, which is equivalent to the pressure change caused by the superposition of the sound wave disturbance on the atmospheric pressure. The pressure changes due to vibrations as the sound waves pass through the medium. It is time-varying and the measured sound pressure is its effective value. The unit is pascal (Pa). The sound pressure level is expressed by 20 times the common logarithm of the ratio of the sound pressure P of a certain sound to the basic sound pressure value P0, i.e. 20lg ^P/P0 In decibels (dB).

Therefore, in this embodiment, the frequency of the non-motor noise and the sound pressure level of the motor noise are obtained; acquiring operation parameters of the new energy vehicle, and acquiring the frequency of a motor noise signal associated with the operation parameters according to the operation parameters; the operation parameters at least comprise the motor rotating speed of the new energy vehicle;

in this embodiment, the acquisition of the operation parameters CAN be realized by reading data information transmitted by a CAN bus of the new energy vehicle. Optionally, the operation parameters of the new energy vehicle may further include a vehicle speed, an accelerator opening degree and the like of the new energy vehicle.

Specifically, the relationship between the motor rotation speed and the frequency of the motor noise signal thereof may be stored in advance. When the operation parameters are collected, the CAN bus of the new energy vehicle CAN be accessed, and the operation parameters such as the rotating speed of the motor, the speed of the vehicle, the opening degree of the accelerator and the like CAN be obtained by reading data transmitted by the CAN bus of the new energy vehicle. And then the relation between the prestored motor rotating speed and the frequency of the motor noise signal CAN be obtained through the CAN bus, and the corresponding frequency of the motor noise signal CAN be obtained according to the motor rotating speed.

Specifically, the operation parameter is taken as the motor rotation speed as an example for explanation. Under different working conditions, the motor rotating speed of the new energy vehicle and a motor noise signal corresponding to the motor rotating speed can be collected; then, the frequency spectrum analyzer can be used for carrying out frequency domain analysis on the collected motor noise signal so as to obtain frequency spectrum characteristic information, such as frequency and sound pressure level, of the motor noise signal; and then the corresponding relation between the motor rotating speed and the frequency and sound pressure level of the motor noise signal can be obtained.

In this embodiment, the harmony structural signal generating step is more advantageous than the method that generates only by a single motor noise signal frequency, and it can further regulate and control the harmony structural signal by the frequency of the non-motor noise in the acoustic environmental noise, so that the generated harmony structural signal is more reasonable. The problem of sound environment quality reduction caused by new reinforced noise signals easily formed by overlapping, interfering and the like with other non-motor noise components by only using the frequency of a single motor noise signal to generate a construction signal is avoided, and thus the sound environment quality is better improved.

The above-described method of generating harmonic constructed signals, still as the principle in the above-described second embodiment, may include two methods:

and acquiring a harmony construction signal corresponding to the motor noise signal by calling a preset construction sound database according to the frequency of the motor noise signal, or acquiring the harmony construction signal corresponding to the motor noise signal through a generation function according to the frequency of the motor noise signal.

The first harmony construction signal acquisition mode: and calling a preset configuration sound database according to the frequency of the motor noise signal to acquire a harmony configuration signal corresponding to the motor noise signal.

The method specifically comprises the following steps:

judging the frequency band of the motor noise signal according to the frequency of the motor noise signal;

calling the preset structure sound database according to the frequency band of the motor noise signal to acquire a harmony structure signal corresponding to the frequency band of the motor noise signal; the preset constructed sound database stores a plurality of constructed sound samples, each constructed sound sample corresponds to a noise frequency band and comprises a harmony constructed signal corresponding to the noise frequency band.

The generation of the harmonic structure signal is the same as the principle in the second embodiment, and is not repeated here.

The second generation method comprises the following steps: and obtaining a harmonic construction signal corresponding to the motor noise signal through a generating function according to the frequency of the motor noise signal. It is described in detail as follows: the motor noise signal comprises fundamental waves and harmonic waves, fundamental wave frequency is obtained from the frequency of the motor noise signal, and the harmony construction signal is obtained through a generating function according to the principle of music acoustics or psychoacoustics, and is subharmonic waves of the fundamental waves in the motor noise signal; wherein the frequency of the harmonic construction signal is at the fundamental frequency

Wherein n and m are natural numbers, and n is less than m. For example, in musical acoustics, a musical interval with a frequency ratio of 2. Frequency ratio of other intervals: minor two 16, major two 9, minor three 6, major three 5, minor four 4, plus four 45, minus five 64, minor five 3, minor six 8, minor seven 16. The musical interval of the music including pure one, pure eight and pure5. And (5) pure IV. The subjective feeling of complete harmony interval is best. By way of example, at two minor degrees, the harmonic construction signal has a frequency of the fundamental frequency

At two degrees, the frequency of the harmonic construction signal is the fundamental frequency

At minor three degrees, the harmonic construction signal has a frequency of the fundamental frequency

At most three degrees, the frequency of the harmonic construction signal is at the fundamental frequency

At pure four degrees, the frequency of the harmonic construction signal is at the fundamental frequency

At four degrees, the harmonic construction signal has a frequency of the fundamental frequency

When reduced by five degrees, the harmonic construction signal has a frequency of the fundamental frequency

At pure five degrees, the harmonic construction signal has a frequency of the fundamental frequency

At six degrees less, the harmonic construction signal has a frequency of the fundamental frequency

At six degrees, the frequency of the harmonic construction signal is the fundamental frequency

At less than seven degrees, the harmonic construction signal has a frequency of the fundamental frequency

Further, the occurrence function expression of the noise reduction structure sound is as follows: y = Ky + b, and Y = asin (2 × pi × a × f × t); where K denotes the slope of the frequency, a denotes the amplitude of the harmonic structure signal, a denotes the harmonic coefficient, f denotes the frequency of the harmonic structure signal, and t denotes time. When the motor noise is constant frequency howling, for example, as shown in fig. 5, we know that a constant frequency of the motor howling is f =5050Hz, and assume that the signal is a sinusoidal signal. It was found through research that the subjective perception of constructing octave harmonic components is best for motor signal construction at this frequency, and we should generate a sinusoidal signal with frequency f/2=2525hz as the harmonic construction signal. Wherein K is 1 and b is 0. If we know that the motor howling is a frequency linearly increasing from 3500Hz to 4300Hz as shown in fig. 6, the occurrence function at this time is the function of the above-mentioned linear ramp.

Specifically, the harmonic structure signal generated in the above step is frequency-removed from the non-motor noise repeated in the acoustic environment noise to generate the harmonic structure signal. The reason is that when the low frequency signal in the non-motor noise is coincident with the harmony structural signal, at this moment, the non-motor noise itself can actually play a role of noise reduction structural sound, the non-motor noise can play a role of fusion noise reduction for the motor noise, and if the harmony structural signal is regenerated for playing, the harmony structural signal is redundant and repetitive in practice. But instead introduces unwanted low frequency noise. Therefore, the harmonic structure signal needs to be adjusted by using the frequency of the non-motor noise to generate the harmonic structure signal; the harmony structural signal considers the influence of non-motor noise, and can avoid the problem of sound environment quality reduction caused by new reinforced noise signals formed by overlapping, interference and the like of non-motor noise components. For example, the frequencies of the acoustic environment noise collected by the acoustic environment collection device include 100Hz, 200Hz, 750Hz, 800Hz, 1000Hz, 6000Hz, and the like, where 6000Hz is motor noise, and the motor noise of 6000Hz needs to be subjected to an acoustic structure, but the existing non-motor noise has noise with the frequency of 750Hz, which is a 3 rd order harmonic wave of the existing non-motor noise, so that when the noise is generated, a signal with the frequency does not need to be generated. The program can be realized by assigning 0 to the value of the subharmonic amplitude a (the magnitude of the subharmonic amplitude determines the loudness of sound, and the loudness corresponds to the sound pressure level) in the generation function y = asin (2 × pi a × f × t).

The "converting the harmony construction signal into a noise reduction audio signal, and adjusting the sound pressure level of the noise reduction audio signal according to the sound pressure level of the motor noise" is specifically explained as follows:

the harmony structural signal generated above is an analog signal, and cannot be directly played in the sound playing device, and must be converted into a digital signal (i.e. a noise reduction audio signal) to be input into the sound playing device for playing. Meanwhile, the sound pressure level of the sound is also regulated, so that the sound pressure level which determines that the sound does not make a sound is prevented from exceeding the range, and new low-frequency noise is generated.

In this example, the sound pressure level of the noise reduction audio signal is equal to or less than the sound pressure level of the collected motor noise, so that, after the noise reduction structure sound played and output in the sound playing device is synthesized with the noise signal of the selected frequency band, the influence of the sound pressure level of the noise reduction structure sound on the sound pressure level of the fused sound is small.

For example, if the noise reduction audio signal is a first order subharmonic, its sound pressure level is half (not a fixed amount) of that of the motor noise, and the sound pressure levels of the other order subharmonics decrease linearly on a first order basis. If the frequency of the motor noise is 4000Hz, 2000Hz, 1000Hz, 500Hz, 250Hz are its octave harmonics, the first order is 4000Hz, 2000 combination Hz, the second order is the combination of 4000Hz, 2000Hz, 1000Hz, and so on.

The implementation in the program was such that the value of a in y = asin (2 x pi a f t) was adjusted to half the noise, the others decreased linearly on a basis.

For example, knowing that the sound pressure level of the motor noise is a, an octave subharmonic harmonic sound signal is constructed to be used as the harmonic construction signal, and the sound pressure level of the subharmonic signal of the first order is a/2, so that the amplitude a of the harmonic construction signal in the occurrence function y = asin (2 × pi a × f × t) is automatically adjusted when generating the noise reduction audio signal.

The high frequency noise reduction scheme provided by this third embodiment collects the frequency of non-motor noise and the sound pressure level of motor noise in the acoustic environment in real time. Acquiring the operating parameters of the new energy vehicle, the frequency of non-motor noise and the sound pressure level of the motor noise; further acquiring the frequency of a motor noise signal corresponding to the operation parameter, and simultaneously generating a harmony construction signal according to the acquired frequency of non-motor noise in the acoustic environment noise and the acquired frequency of the motor noise signal; converting the harmony construction signal into a noise reduction audio signal, and adjusting the sound pressure level of the noise reduction audio signal according to the sound pressure level of the motor noise; and then inputting the noise reduction audio signal into a sound playing device for playing so as to output noise reduction structure sound. Therefore, the noise reduction structure sound played by the sound playing device is fused with the sound environment noise, the generated harmony structure signal not only considers the frequency of the motor noise signal, but also comprehensively considers the sound pressure level of other non-motor noises and motor noises in the sound environment, and the problem of sound environment quality reduction caused by the fact that the structure signal generated by only relying on the frequency of one motor noise signal is easy to form a new enhanced noise signal with other non-motor noise components due to overlapping, interference and the like is avoided, and the sound environment quality is better improved. The improved scheme can effectively solve the problem of high-frequency noise caused by the increase of the vehicle speed, and the method is easy to implement, simple and easy to operate.

As a preferred implementation manner, the fourth embodiment has the same main steps as those of the second and third embodiments, and only some of the steps are optimized, and preferably, the step S2A specifically includes the following steps:

constructing and generating the harmony construction signal according to the frequency of the high-frequency noise signal, wherein the harmony construction signal is a harmony masking signal; wherein the harmonic masking signal comprises a harmonic signal and a masking signal; the harmonic signal is a subharmonic of the high frequency noise signal.

We have understood the principle of generating the harmonic structure signal by the subharmonic structure through the first to third embodiments described above, and first determined the frequency component (generally, a high-frequency signal in a vehicle in a motor operating state) causing discomfort when performing a subharmonic structure, and musical interval-structured the subharmonic in correspondence with the musical acoustic harmonic component. A large number of experiments are carried out to obtain the harmonic generation device which accords with the rule of us and generates fourth subharmonic, third subharmonic and second subharmonic (for example, if a fundamental frequency signal is 1000Hz, the generated fourth subharmonic of octave is 500Hz, 250Hz, 125Hz and 62.5Hz, the third subharmonic is 500Hz, 250Hz and 125Hz, and the second subharmonic is 500Hz and 250 Hz). Then, harmonic components of corresponding pitch changes are generated, respectively, and the pitch changes are generally three types: the linearity is unchanged, decreased and increased. Thus, the octave which is a musical interval can generate 9 different harmony components, and then the harmony components are subjectively evaluated by an organizer, and finally fourth subharmonics are selected, and harmony combinations with linearly reduced pitches are optimal.

Meanwhile, in later experiments and researches, the fact that a sound signal with a frequency close to that of the target sound is added to the target sound while the harmony construction is carried out is found, the sound signal is called a masking signal for distinguishing, and after the masking signal is added, the subjective feeling is improved to a greater extent.

Based on the principle of the masking signal, when generating the harmony construction signal, on one hand, the signal with the subharmonic construction is adopted, on the other hand, the masking signal is added, and the noise reduction signal generated in the way is used as the harmony construction signal, so that the sound quality can be further improved.

Similarly, for the high-frequency noise signal, the two above methods may also be adopted to collect the high-frequency noise signal (directly collecting the parameters such as the frequency of the motor noise by the microphone, or indirectly obtaining the parameters such as the frequency of the motor noise by collecting the operation parameters of the noise source).

The sum-sound masking signal is obtained by the following steps:

harmony signal generation step: constructing and generating a harmony signal according to the frequency of the high-frequency noise signal;

a masking signal generating step: constructing and generating a masking signal according to the frequency of the high-frequency noise signal;

compounding: and compounding the harmony signal and the masking signal to obtain the harmony masking signal.

It can be seen that the harmonic signal generation step is actually the harmonic structural signal generation step already disclosed in the second embodiment and the third embodiment, and therefore, the details are not repeated.

The action of the masking signal and its mechanism of generation are explained as follows: the masking signal is effective when a stronger sound conceals a weaker sound from hearing, a phenomenon known as "masking". When listening to two or more sounds simultaneously, the auditory system produces the so-called "masking effect" in that each pure tone becomes more or less audible, or is partially or completely "masked", by the property that it generates a "masking signal" for the high frequency noise, which renders the high frequency noise signal less audible, the "masking signal" being at a lower frequency than the noise signal. This allows, on the one hand, to act as a masking of the noise signal and, on the other hand, to slightly reduce the sharpness, at least without increasing the sharpness. Therefore, for the masking signal, on the one hand, the frequency is required to be lower than that of the high-frequency noise signal, and in addition, the sound pressure level of the masking signal is consistent with the trend of the sound pressure level of the harmonic signal. By trend consistent it is meant that it matches the trend of the sound pressure level of the harmonic signal, e.g. the masking signal is also reduced in pitch relative to the high frequency noise signal, assuming that the sound pressure level of the harmonic signal is reduced linearly as a whole, but it is noted that the reduced amplitude does not necessarily have to be consistent with the reduced amplitude of the harmonic signal. If the sound pressure level of the harmonic signal is kept constant, the sound pressure level of the masking signal is also kept uniform with respect to the sound pressure level of the high frequency noise signal.

As shown in fig. 7 and 8, the horizontal axis represents frequency and the vertical axis represents relative sound pressure level; where the thick solid lines represent high frequency noise signals, the thin solid lines represent masking signals, and the dashed lines represent harmonic signals. As shown in fig. 7, the "octave" subharmonic of the harmonic signal high frequency noise signal shown by the dotted line always satisfies the relationship of 1. In this example, the sound pressure level of the subharmonic wave tends to decrease linearly as a whole, and therefore, the sound pressure level of the masking signal is relatively smaller than the sound pressure level of the high-frequency noise signal, thereby masking the noise signal.

As shown in fig. 8, the sum sound signal shown by the dotted line is an odd-numbered subharmonic of the high-frequency noise signal, the odd-numbered relationship is always satisfied between the frequency of the subharmonic and the frequency of the "high-frequency noise signal, and the frequency of the masking signal is slightly smaller than that of the high-frequency noise signal. The loudness of the harmonic signal in this example is the same but smaller than that of the noise signal. The sound pressure level of the masking signal is set to be the same as the sound pressure level of the high frequency noise signal.

It should be noted that, in different combinations, the frequency relationship, loudness, and harmonic frequency between the high-frequency noise signal, masking signal, and harmonic signal are different, and their subjective feelings are also different. The combination that is subjectively best perceived can be selected experimentally. It is not intended to be exhaustive or to limit the invention to the precise form disclosed.

For example, the masking signal may be obtained by:

presetting masking signals to be selected with N frequencies, synchronously playing the masking signals to be selected and the high-frequency noise signals one by one, carrying out subjective evaluation, and selecting the masking signals to be selected with the best subjective evaluation as the masking signals; the preset N frequencies are all smaller than the frequency of the high-frequency noise signal; the sound pressure level of the masking signal is in accordance with the sound pressure level variation trend of the harmony signal.

Alternatively, as a preferable aspect, a plurality of sound pressure levels may be set and subjectively evaluated in combination. Specifically, presetting N frequencies and M preselected sound pressure levels, and combining the N frequencies and the M preselected sound pressure levels to generate N × M masking signals to be selected; synchronously playing the N × M masking signals to be selected and the high-frequency noise signals one by one, performing subjective evaluation, and selecting the masking signal to be selected with the best subjective evaluation as the masking signal; wherein the sound pressure level of the masking signal to be selected is less than the sound pressure level of the high-frequency noise signal; the preset N frequencies are all smaller than the frequency of the high-frequency noise signal.

Wherein the range of the N frequencies is [ f0-a, f0-b ]; wherein f0 is the frequency of the high-frequency noise signal, and the three satisfy the following expression: f0 > a > b; wherein a and b are empirical values.

For example, assume that in the above expression, a =150hz, b =50hz; selecting N =10 in a frequency range (50, 150) smaller than the high-frequency noise signal, and generating 10 masking signals to be selected by a step length of 10 Hz; and playing the 10 masking signals to be selected and the high-frequency noise signals together for subjective evaluation, and selecting a group with the best subjective evaluation.

In the active sound control method provided by the embodiment, the subharmonic signal of the high-frequency noise signal is constructed as the harmonic signal on one hand, and meanwhile, a masking signal with the frequency close to that of the high-frequency noise signal is added on the basis of the harmonic signal to mask the high-frequency noise signal, the ratio of the high-frequency component of the noise in the whole frequency domain can be reduced by adding the subharmonic, and the amount of the high-frequency component reflects the degree of the dysphoria, so that the dysphoria is reduced. Also, the addition of the masking signal can obscure the high frequency noise signal and reduce the level of fidget. Thus, the sound quality of the sound environment can be further improved. Meanwhile, the method is simple and easy to operate and low in cost.

As a preferable mode, the fifth embodiment has the same main steps as those of the first to fourth embodiments, and only preferable steps are added. As shown in fig. 4, the active sound control method shown in this example further includes a step S4 for emitting a warning sound.

Specifically, as shown in fig. 5, the step S4 specifically includes the following steps:

s41, a condition judging step: judging whether a warning tone playing condition is triggered or not, and entering the following step S42 when the warning tone playing condition is triggered;

s42, vehicle speed acquisition step: acquiring the speed of the new energy vehicle;

s43, prompt tone playing: comparing the vehicle speed with a preset threshold value; and when the vehicle speed is greater than or equal to the preset threshold value, playing a first prompt tone outside the vehicle. After the speed of a motor vehicle exceeded and predetermine the threshold value, can be used to broadcast the first prompt tone that relatively accords with real driving situation, warn the personnel outside the car.

Preferably, the step S43 further includes the steps of: and when the vehicle speed is less than the preset threshold value, playing a second prompt tone. The second warning sound can be used for generating a warning sound outside the vehicle to warn pedestrians on the road. The warning sound may be a steady engine sound or other sound that may attract the attention of a pedestrian or the like. Or the second prompt sound can be played to the interior of the vehicle, so that the condition that the attention of a driver is not concentrated due to the fact that the interior of the vehicle is too quiet is prevented.

The second warning sound is a low speed warning pedestrian sound, and the first warning sound is an accelerating and high speed brand identification sound. We need to specify a preset threshold (threshold speed) that determines the high and low speeds, which can be determined according to local regulations (or as needed). When the speed is lower than the threshold value, the speed is considered to be in a low speed state, and a warning sound (a second warning sound) needs to be generated outside the vehicle to warn pedestrians on the road and the like. The warning sound may be a steady engine sound or other sound that may attract the attention of a pedestrian or the like. After the vehicle speed exceeds the threshold speed, a second warning tone is generated to attract the attention of the pedestrian. For example, the sound which is relatively accordant with the real driving condition is generated by combining the vehicle speed, the accelerator opening and closing degree, the motor rotating speed, the brake related information and the like. For example, with respect to the first alert tone, differently located cars may have different brand recognition characteristics, such as the ability to close the eyes to distinguish sports cars from ordinary cars. Therefore, when the warning sound outside the vehicle is designed and played, the warning sound outside the vehicle is selected in a targeted mode. For the Qin series cars of our company, we design a first prompt tone to select a running warning tone; SUV in the Tang series designed a second warning tone to select the warning tone of the off-road vehicle. Preferably, the first and second warning sounds may be set manually, and a voice to be presented may be selected. For example, the customer may select the favorite alert tone types as the first alert tone and the second alert tone according to the preference. The audio frequency storage modules of the first prompt tone and the second prompt tone are designed to be pluggable to a memory card, which is similar to a memory card of a mobile phone. The replacement can be done by simply adjusting the relevant type match.

A sixth embodiment of the present invention specifically explains the active sound system disclosed in the present invention, as shown in fig. 9, including a noise collection module 1, an active sound controller 2, and a sound playing device 3;

the noise acquisition module 1 is used for acquiring noise signals in a new energy vehicle sound environment, wherein the noise signals comprise high-frequency noise signals with high frequency and low-frequency noise signals with low frequency;

the active sound controller 2 is configured to acquire the high-frequency noise signal and generate a harmony construction signal according to the high-frequency noise signal; acquiring the low-frequency noise signal, and generating a phase de-noising signal which is opposite in phase and has the same amplitude as the low-frequency noise according to the low-frequency noise signal;

the sound playing device 3 is used for playing the harmony construction signal, and playing noise reduction construction sound fused with high-frequency noise in the new energy vehicle sound environment so as to perform noise reduction processing on the high-frequency noise; and playing the phase noise-canceling signal, and playing phase noise-canceling sound with the same amplitude as the phase noise in opposite phase with the low-frequency noise so as to cancel the low-frequency noise.

The active sound system 100 provided by this embodiment comprehensively solves the noise problem in the existing new energy vehicle, and the active sound controller 2 generates a phase noise canceling signal for low-frequency noise such as road noise and tire noise according to the difference of noise frequencies, plays the phase noise canceling sound with opposite phase and equal amplitude through the sound playing device 3 to perform noise canceling processing, and generates noise reduction structure sound for high-frequency noise such as a motor, and then plays the noise reduction structure sound integrated with the high-frequency noise through the sound playing device 3 to perform noise reduction processing on the high-frequency noise, thereby eliminating the low-frequency noise in the vehicle, and performs noise reduction processing on the high-frequency noise at the same time, so that drivers and passengers have a very high-quality sound quality environment no matter what kind of working conditions in the vehicle are.

The noise acquisition module 1 specifically acquires a noise signal by acquiring a noise signal through a microphone arranged in an acoustic environment or acquiring working condition information of a vehicle through a sensor, and acquires the noise signal by reading data information transmitted by a CAN bus of the new energy vehicle.

As shown in fig. 11, the active acoustic controller 2 includes the following modules:

a harmony structural signal generating module 21, configured to obtain the high-frequency noise signal, and generate a harmony structural signal according to the high-frequency noise signal;

and a phase noise cancellation signal generating module 22, configured to acquire the low-frequency noise signal, and generate a phase noise cancellation signal with an inverse phase and a same amplitude as the low-frequency noise according to the low-frequency noise signal.

As shown in fig. 12, the sound playing device 3 includes a first playing device 31 and a second playing device 32;

the first playing device 31 is configured to play the harmony construction signal, and play a noise reduction construction sound fused with a high-frequency noise in the new energy vehicle sound environment to perform noise reduction processing on the high-frequency noise;

the second playing device 32 is configured to play the phase de-noising signal, and play the phase de-noising sound with the same amplitude and opposite phase as the low-frequency noise to eliminate the low-frequency noise.

The first playback device 31 and the second playback device 32 may be playback devices disposed at different positions in an acoustic environment, or may be playback devices integrated into one body.

As a preferred mode, as shown in fig. 10, the system further includes a warning sound playing module 4, specifically, as shown in fig. 13, the warning sound playing module 4 includes the following units:

a condition judgment unit 41 for judging whether or not a warning sound playing condition is triggered;

the vehicle speed obtaining unit 42 is used for obtaining the vehicle speed of the new energy vehicle;

a third playing device 43, configured to compare the vehicle speed with a preset threshold; and when the vehicle speed is greater than or equal to the preset threshold value, playing a first prompt tone outside the vehicle.

The third playback device 43 may be the first playback device 31 or the second playback device 32, or a playback device integrated with the first playback device 31 and the second playback device 32.

This warning sound play module 4 can be used to broadcast the first warning sound that relatively accords with real driving situation after the speed of a motor vehicle surpassed preset threshold value, warns the personnel outside the car.

Preferably, the third playing device 43 is further configured to play a second prompt sound outside and/or inside the vehicle when the vehicle speed is less than the preset threshold.

This warning sound play module 4 can be used to broadcast the first warning sound that relatively accords with real driving situation after the speed of a motor vehicle surpassed preset threshold value, warns the personnel outside the car. When the speed of a motor vehicle is less than preset threshold value, broadcast the second warning sound, be used for producing a warning sound outside the car and warn the pedestrian on the road. The warning sound may be a steady engine sound or other sound that may attract the attention of a pedestrian or the like. Or the second prompt tone can be played to the interior of the vehicle, so that the situation that the driver is distracted due to too quiet interior of the vehicle is prevented.

As shown in fig. 14, a seventh embodiment of the present invention discloses a new energy vehicle 1000, which includes the active sound system 100 disclosed in the second embodiment.

Since only the active sound system 100 of the new energy vehicle 1000 is improved in this embodiment, and improvement of other structures and systems is not involved, and the active sound system 100 and the active sound control method thereof have been specifically described in the above embodiments, and are not repeated herein.

The new energy vehicle 1000 provided by the invention integrates an active sound system 100 in the vehicle, so that the noise problem in the existing new energy vehicle is comprehensively solved, the active sound controller 2 generates phase noise elimination signals for low-frequency noise such as road noise, tire noise and the like according to the difference of noise frequencies, the sound playing device 3 plays the phase noise elimination sound with opposite phase and equal amplitude for noise elimination, and the sound playing device 3 plays the noise reduction structure sound which is fused with the high-frequency noise for high-frequency noise such as a motor and the like for noise reduction, so that the high-frequency noise is subjected to noise reduction processing, the low-frequency noise in the vehicle is eliminated, and meanwhile, the high-frequency noise is subjected to noise reduction processing, so that drivers and passengers have a very high-quality sound quality environment under any working condition in the vehicle.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. An active sound control method, comprising the steps of:

playing the harmony construction signal, and playing noise reduction construction sound fused with high-frequency noise in the new energy vehicle sound environment to perform noise reduction processing on the high-frequency noise; playing the phase noise-canceling signal, and playing phase noise-canceling sound with opposite phase and equal amplitude to the low-frequency noise to cancel the low-frequency noise;

the "generating a harmonic structure signal according to the high-frequency noise signal" specifically includes the following steps:

constructing and generating the harmony construction signal according to the frequency of the high-frequency noise signal, wherein the harmony construction signal is a harmony masking signal; the harmony masking signal comprises a harmony signal and a masking signal; the harmonic signal is a subharmonic of the high frequency noise signal.

2. The active sound control method according to claim 1, wherein the step of "collecting noise signals in the new energy vehicle sound environment" specifically comprises the steps of:

3. The active sound control method according to claim 1, wherein the step of "collecting noise signals in the new energy vehicle sound environment" specifically comprises the steps of:

the step of playing the harmony construction signal and playing the noise reduction construction sound fused with the high-frequency noise in the new energy vehicle sound environment to perform noise reduction processing on the high-frequency noise specifically comprises the following steps:

4. The active sound control method of any one of claims 1-3, further comprising the steps of:

judging whether a warning tone playing condition is triggered or not, and when the warning tone playing condition is triggered, entering the following steps:

collecting the speed of the new energy vehicle;

5. The active sound control method of claim 4, further comprising the steps of: and when the vehicle speed is less than the preset threshold value, playing a second prompt tone outside and/or inside the vehicle.

6. An active sound system is characterized by comprising a noise acquisition module, an active sound controller and a sound playing device;

the noise acquisition module is used for acquiring noise signals in a new energy vehicle sound environment, wherein the noise signals comprise high-frequency noise signals with high frequency and low-frequency noise signals with low frequency;

the sound playing device is used for playing the harmony construction signal and playing noise reduction construction sound fused with high-frequency noise in the new energy vehicle sound environment so as to perform noise reduction processing on the high-frequency noise; playing the phase noise-canceling signal, and playing phase noise-canceling sound with opposite phase and equal amplitude with the low-frequency noise to cancel the low-frequency noise;

the active acoustic controller comprises the following modules:

the harmony construction signal generating module is used for acquiring the high-frequency noise signal and generating a harmony construction signal according to the high-frequency noise signal; the "generating a harmonic structure signal according to the high-frequency noise signal" specifically includes: constructing and generating the harmony construction signal according to the frequency of the high-frequency noise signal, wherein the harmony construction signal is a harmony masking signal; the harmony masking signal comprises a harmony signal and a masking signal; the harmonic signal is a subharmonic of the high-frequency noise signal;

and the phase noise-eliminating signal generating module is used for acquiring the low-frequency noise signal and generating a phase noise-eliminating signal with the inverse phase and the same amplitude with the low-frequency noise according to the low-frequency noise signal.

7. The active sound system of claim 6, wherein the noise collection module collects noise signals through a microphone disposed in an acoustic environment, collects vehicle operating condition information through a sensor, and collects the noise signals by reading data information transmitted by a CAN bus of the new energy vehicle.

8. The active sound system according to claim 7, wherein the sound playing means comprises a first playing means and a second playing means;

and the second playing device is used for playing the phase de-noising signal and playing phase de-noising sound with opposite phase and equal amplitude with the low-frequency noise so as to eliminate the low-frequency noise.

9. The active sound system of claim 8, further comprising a warning tone playing module, the warning tone playing module comprising:

the third playing device is used for comparing the vehicle speed with a preset threshold value; and when the vehicle speed is greater than or equal to the preset threshold value, playing a first prompt tone outside the vehicle.

10. The active sound system according to claim 9, wherein the third playback device is further configured to play a second warning sound to the outside of the vehicle and/or the inside of the vehicle when the vehicle speed is less than the preset threshold.

11. A new energy vehicle comprising an active sound system according to any one of claims 6 to 10.