Vehicle noise reduction method and system, vehicle and computer readable storage medium

Abstract

The invention provides a vehicle noise reduction method and system, a vehicle and a computer readable storage medium. The method comprises the steps that tire vibration data and in-vehicle noise data are obtained; performing coherence analysis on the tire vibration data and the in-vehicle noise data, and determining a target frequency signal in the tire vibration data; a noise reduction frequency signal corresponding to the target frequency signal is determined, and the phase of the noise reduction frequency signal is opposite to that of the target frequency signal; a wheel actuator of the vehicle is controlled to vibrate with the noise reduction frequency signal. The target frequency signal having the maximum coherence with the in-vehicle noise is determined in the tire vibration data, so that the main tire source of the in-vehicle noise can be determined, the noise reduction frequency signal with the phase opposite to that of the target frequency signal is generated, the target frequency signal can be eliminated when the wheel actuator vibrates according to the noise reduction frequency signal, and the noise reduction efficiency is improved. Therefore, the noise of the tire is reduced at the noise source, and the NVH performance in the vehicle is greatly optimized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicles, in particular to a vehicle noise reduction method, system, vehicle and computer readable storage medium. BACKGROUND

[0002] Tire noise vibration is the vibration generated by the tire in contact with the road surface during rolling, and the main frequency is 20-300Hz, among which the tire cavity sound with a frequency of 180-250Hz is particularly obvious. The sound wave energy is transmitted to the vehicle body through the hub and the horn in the suspension system, which significantly affects the in-vehicle NVH (Noise, Vibration, Harshness) performance. SUMMARY

[0003] The main purpose of the present application is to provide a vehicle noise reduction method, system, vehicle and computer readable storage medium, which aims to solve the problem of tire noise affecting in-vehicle NVH performance in the prior art.

[0004] To achieve the above-mentioned purpose, the present application provides a vehicle noise reduction method, which comprises the following steps: Obtaining tire vibration data and in-vehicle noise data; Performing coherence analysis on the tire vibration data and the in-vehicle noise data to determine a target frequency signal in the tire vibration data, wherein the target frequency signal is a frequency signal in the tire vibration data that has the maximum coherence with the in-vehicle noise data; Determining a noise reduction frequency signal corresponding to the target frequency signal, wherein the noise reduction frequency signal is opposite in phase to the target frequency signal; Controlling the wheel actuator of the vehicle to vibrate at the noise reduction frequency signal, wherein the wheel actuator is arranged on the horn of the vehicle.

[0005] Optionally, the coherence analysis of the tire vibration data and the in-vehicle noise data to determine the target frequency signal in the tire vibration data comprises: Obtaining a plurality of directional sub-data in the tire vibration data, wherein each directional sub-data corresponds to a vibration direction, and each vibration direction is orthogonal to each other; For each directional sub-data, performing coherence analysis on the directional sub-data and the in-vehicle noise data to determine a target frequency sub-signal in the directional sub-data; Generating the target frequency signal containing each target frequency sub-signal.

[0006] Optionally, the controlling the wheel actuator of the vehicle to vibrate at the noise reduction frequency signal, wherein the wheel actuator is arranged on the horn of the vehicle comprises: Obtain the noise reduction sub-signal corresponding to each vibration direction in the noise reduction frequency signal, wherein the noise reduction sub-signal is out of phase with the target frequency sub-signal corresponding to the same vibration direction; For each noise reduction sub-signal, a corresponding vibration absorption unit is determined according to the corresponding vibration direction. The wheel actuator includes multiple vibration absorption units, each vibration absorption unit corresponds to a different vibration direction, and the vibration directions of each vibration absorption unit are orthogonal to each other. Each of the vibration-absorbing units is controlled to vibrate according to the corresponding noise-reducing sub-signal.

[0007] Optionally, the step of performing coherence analysis on the tire vibration data and the in-vehicle noise data to determine the target frequency signal in the tire vibration data includes: The tire vibration data is subjected to a fast Fourier transform to obtain a first frequency signal, and the in-vehicle noise data is subjected to a fast Fourier transform to obtain a second frequency signal. Calculate the first auto-power spectral density corresponding to each frequency in the first frequency signal, and calculate the second auto-power spectral density corresponding to each frequency in the second frequency signal; Calculate the cross-power spectral density of the first frequency signal and the second frequency signal at each frequency; The coherence intensity corresponding to each frequency is calculated using the first self-power spectral density, the second self-power spectral density, and the cross-power spectral density. The target frequency signal with the highest coherence intensity is determined from the tire vibration data.

[0008] Optionally, the wheel actuator of the controlled vehicle vibrates with the noise-reducing frequency signal, and the wheel actuator is disposed at the steering knuckle of the vehicle, comprising: Determine the target noise reduction frequency corresponding to the noise reduction frequency signal; Obtain the hardware parameters of the wheel actuator; The target stiffness is determined based on the target noise reduction frequency and the hardware parameters. A control signal indicative of the target stiffness is sent to the wheel actuator to cause the wheel actuator to vibrate at the target stiffness to generate the noise reduction frequency signal.

[0009] To achieve the above objectives, the present invention also provides a vehicle noise reduction system applied to the vehicle noise reduction method described above; the vehicle noise reduction system includes a vibration sensor, a noise sensor, a data processing module, and a wheel actuator; wherein, the vibration sensor and the wheel actuator are disposed in the steering knuckle of the vehicle, and the noise sensor is disposed in the passenger space of the vehicle; the data acquisition terminal of the data processing module is connected to the vibration sensor and the noise sensor respectively, and the output terminal of the data processing module is connected to the control terminal of the wheel actuator.

[0010] Optionally, the wheel actuator is provided on each steering knuckle of the vehicle; the wheel actuator includes multiple vibration absorption units, each vibration absorption unit corresponds to a different vibration direction, and the vibration directions corresponding to each vibration absorption unit are orthogonal to each other; the control terminal of each vibration absorption unit is connected to the output terminal of the data processing module.

[0011] Optionally, the wheel actuator further includes a self-powered unit; the self-powered unit includes a piezoelectric power generation unit; the power output terminal of the piezoelectric power generation unit is connected to the power supply terminal of the vibration sensor and the power supply terminal of the wheel actuator, respectively.

[0012] To achieve the above objectives, the present invention also provides a vehicle including the vehicle noise reduction system described above.

[0013] To achieve the above objectives, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the vehicle noise reduction method described above.

[0014] This invention proposes a vehicle noise reduction method, system, vehicle, and computer-readable storage medium. The method involves acquiring tire vibration data and in-vehicle noise data; performing coherence analysis on the tire vibration data and in-vehicle noise data to determine a target frequency signal in the tire vibration data, wherein the target frequency signal is the frequency signal in the tire vibration data that has the highest coherence with the in-vehicle noise data; determining a noise reduction frequency signal corresponding to the target frequency signal, wherein the noise reduction frequency signal is out of phase with the target frequency signal; and controlling the vehicle's wheel actuators to vibrate at the noise reduction frequency signal, wherein the wheel actuators are located at the steering knuckles of the vehicle. By determining the target frequency signal with the highest coherence with in-vehicle noise in the tire vibration data, the main tire source of in-vehicle noise can be identified. This allows for the generation of a noise reduction frequency signal with an out-of-phase target frequency signal, enabling the wheel actuators to eliminate the target frequency signal when vibrating at the noise reduction frequency signal. This achieves noise reduction at the noise source, significantly optimizing in-vehicle NVH performance. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the first embodiment of the vehicle noise reduction method of the present invention; Figure 2 This is a schematic diagram of the vibration transmission path in the vehicle noise reduction method of the present invention; Figure 3 This is a schematic diagram of the vehicle noise reduction system of the present invention; Figure 4 This is a functional schematic diagram of a specific structure in the vehicle noise reduction system of the present invention.

[0018] Explanation of icon numbers: Detailed Implementation

[0019] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0020] This invention provides a vehicle noise reduction method, referring to... Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the vehicle noise reduction method of the present invention, the method comprising the following steps: Step S10: Obtain tire vibration data and vehicle interior noise data; Tire vibration data is used to indicate the vibration status of the tire; tire vibration data can be detected by corresponding sensors, such as vibration sensors.

[0021] In-vehicle noise data is used to indicate the noise level inside the vehicle, specifically within the passenger space; in-vehicle noise data can be collected by installing noise sensors.

[0022] Step S20: Perform coherence analysis on the tire vibration data and the in-vehicle noise data to determine the target frequency signal in the tire vibration data, wherein the target frequency signal is the frequency signal in the tire vibration data that has the maximum coherence with the in-vehicle noise data. Coherence analysis identifies the components with the greatest coherence between tire vibration data and in-vehicle noise data. Coherence indicates the correlation between the contents of tire vibration data and in-vehicle noise data, specifically the degree of linear correlation between them at a particular frequency. If a frequency in the tire vibration data has a high coherence with the in-vehicle noise data, then that frequency is considered to directly cause an increase in in-vehicle noise. Coherence analysis thus identifies the component in the tire vibration data that contributes the most to in-vehicle noise.

[0023] The target frequency signal is the frequency signal in the tire vibration data that has the greatest coherence with the in-vehicle noise data; that is, the target frequency signal causes the maximum increase in in-vehicle noise.

[0024] Step S30: Determine the noise reduction frequency signal corresponding to the target frequency signal, wherein the noise reduction frequency signal is out of phase with the target frequency signal; Since the target frequency signal has the highest coherence with the in-vehicle noise data, noise reduction of the target frequency signal can effectively reduce in-vehicle noise.

[0025] The noise reduction frequency signal is a noise reduction signal set for the target frequency signal. It can be understood that, based on the reverse cancellation principle of active noise reduction, by emitting a noise reduction signal with the opposite phase and the same amplitude as the noise signal, the noise signal can be resonantly absorbed, thereby achieving noise reduction for the noise signal. Therefore, in this embodiment, the noise reduction frequency signal set with the same amplitude and opposite phase as the target frequency signal can achieve noise reduction for the target frequency signal.

[0026] Step S40: Control the wheel actuator of the vehicle to vibrate at the noise reduction frequency signal, the wheel actuator being disposed at the horn of the vehicle.

[0027] A wheel actuator is a device installed on the wheel to achieve active vibration. Because the wheel actuator is located at the wheel position, vibration with a noise-reducing frequency signal by the wheel actuator can directly reduce the noise of the target frequency signal at the wheel position, thereby eliminating or reducing the target frequency signal component generated by tire vibration. This prevents the target frequency signal from reaching the vehicle interior and therefore, it also prevents the generation of corresponding noise, thus reducing in-vehicle noise. At the same time, since the target frequency signal and the in-vehicle noise signal have the greatest coherence relationship, eliminating the target frequency signal can greatly reduce in-vehicle noise.

[0028] This embodiment is in contrast to active noise reduction schemes; active noise reduction relies on vibration sensors, speakers, and noise reduction algorithms, resulting in high technical costs and difficulty in covering multiple vibration transmission paths; see [link to relevant documentation]. Figure 2 The vehicle structure is described in one scenario. The vehicle includes a left front wheel, a left rear wheel, a right front wheel, and a right rear wheel. The vibration generated by the left front wheel first reaches the left front knuckle (steering knuckle), then reaches the steering gear through the left steering tie rod, and then reaches the body panel through the front subframe and steering column, the left lower control arm, and the left front shock absorber. The vibration generated by the right front wheel first reaches the right front steering knuckle, then reaches the steering gear through the right steering tie rod, then reaches the front subframe through the lower control arm, and finally reaches the body panel through the right front shock absorber. The vibration generated by the left rear wheel first reaches the left rear steering knuckle, then passes through the left rear damper, left rear spring, and left rear trailing arm to the body panel, and then through the left rear lower front control arm, left rear upper control arm, left rear toe-adjusting rod, and left rear lower rear control arm to the rear subframe and finally to the body panel. The vibration generated by the right rear wheel first reaches the right rear steering knuckle, then through the right rear damper, right rear spring, and right rear trailing arm to the body panel, and then through the right rear lower front control arm, right rear upper control arm, right rear toe-adjusting rod, and right rear lower rear control arm to the rear subframe and finally to the body panel. Vibrations on the vehicle body panels cause low- to mid-frequency road noise inside the vehicle.

[0029] This embodiment reduces noise at the noise source, namely the horn position, which is technically easy to implement and can comprehensively intercept noise transmission, achieving a better noise reduction effect.

[0030] Compared to passive noise reduction solutions based on wheel structure, this embodiment improves the wheel structure, such as by attaching sound-dampening elements to the inner wall of the tire or changing the volume and shape of the tire cavity, thereby reducing the resonance phenomenon of sound waves propagating in the tire cavity and reducing tire cavity noise. This method requires modification of the tire structure, which is costly, and its effective frequency range is narrow, only addressing noise caused by cavity sound. In contrast, this embodiment does not require modification of the original vehicle structure, only the addition of a few components, resulting in lower cost. At the same time, it can precisely target specific frequencies for noise reduction, achieving a wider effective frequency range and meeting noise reduction needs in more scenarios.

[0031] This embodiment collects tire vibration data and in-vehicle noise data in real time, and controls the wheel actuators to vibrate to achieve noise reduction. This enables real-time noise reduction based on the vehicle's operating conditions, such as road conditions and speed, from the noise source, resulting in strong stability and significant noise reduction effect.

[0032] The vehicle noise reduction method of this application is applied to a vehicle noise reduction system. For ease of explanation, the structure of the vehicle noise reduction system will be described first.

[0033] This invention provides a vehicle noise reduction system, applied to the vehicle noise reduction method described above; see also Figure 3 The vehicle noise reduction system includes a vibration sensor 1, a noise sensor 2, a data processing module 4, and a wheel actuator 3; wherein, the vibration sensor 1 and the wheel actuator 3 are disposed in the steering knuckle of the vehicle, and the noise sensor 2 is disposed in the passenger space of the vehicle; the data acquisition terminal of the data processing module 4 is connected to the vibration sensor 1 and the noise sensor 2 respectively, and the output terminal of the data processing module 4 is connected to the control terminal of the wheel actuator 3.

[0034] Vibration sensor 1 is used to collect wheel vibration data. Specifically, vibration sensor 1 can be a triaxial accelerometer, collecting vibration signals along the X, Y, and Z axes respectively, and then synthesizing the collected wheel vibration data. In this embodiment, vibration sensor 1 is specifically installed at the steering knuckle of the vehicle. Since the main transmission path after tire noise is generated is through the suspension system, especially the steering knuckle, this embodiment can accurately collect wheel vibration data from the tire vibration that is the source of the noise. Furthermore, vibration sensor 1 can be installed within 5cm of the connection between the steering knuckle and the wheel actuator 3. Simultaneously, the measurement range of vibration sensor 1 can be ±200g to cover various road conditions and application scenarios.

[0035] Noise sensor 2 is used to collect noise data inside the vehicle; noise sensor 2 can be a microphone; it is understood that the main purpose of noise reduction inside the vehicle is to avoid the passengers being affected by noise. Therefore, when setting noise sensor 2, it can be placed at the headrest of the seat inside the vehicle to collect noise at the user's ears; the dynamic range of noise sensor 2 can be set according to actual needs, such as 140dB.

[0036] The data processing module 4 is used to execute the above-mentioned vehicle noise reduction method; the data processing module 4 can be a stand-alone processing device or a control system with data processing capabilities in the vehicle, such as the vehicle infotainment system.

[0037] The wheel actuator 3 is a device installed on the wheel to achieve active vibration. Since tire noise is a mid-to-low frequency noise, the noise range is generally 20~300Hz. Therefore, the coverage range of the wheel actuator 3 can be specifically selected based on the tire noise range, such as selecting a wheel actuator 3 with a frequency coverage range of 20~300Hz.

[0038] See Figure 4Vibration sensor 1 collects wheel vibration data in real time and sends the wheel vibration data to data processing module 4; noise sensor 2 collects in-vehicle noise data in real time and sends the in-vehicle noise data to data processing module 4; data processing module 4 performs coherence analysis on tire vibration data and in-vehicle noise data, determines the target frequency signal in tire vibration data, and determines a noise reduction frequency signal with a phase opposite to the target frequency signal, thereby controlling the vehicle's wheel actuator 3 to vibrate with the noise reduction frequency signal.

[0039] This embodiment identifies the target frequency signal with the greatest coherence to the in-vehicle noise from the tire vibration data, thereby clarifying the main tire source of the in-vehicle noise. It then generates a noise reduction frequency signal with the opposite phase to the target frequency signal, so that when the wheel actuator 3 vibrates with the noise reduction frequency signal, the target frequency signal can be eliminated. This enables noise reduction of tire noise at the noise source, greatly optimizing the in-vehicle NVH performance.

[0040] Furthermore, a wheel actuator 3 is provided on each steering knuckle of the vehicle; the wheel actuator 3 includes multiple vibration absorption units, each vibration absorption unit corresponds to a different vibration direction, and the vibration directions corresponding to each vibration absorption unit are orthogonal to each other; the control terminal of each vibration absorption unit is connected to the output terminal of the data processing module 4.

[0041] It is understood that a vehicle includes multiple steering knuckles, such as the left front steering knuckle, right front steering knuckle, left rear steering knuckle, and right rear steering knuckle; and the noise generated by the vibration of different tires will be transmitted through the corresponding steering knuckles. Therefore, in this embodiment, a wheel actuator 3 is set for each steering knuckle, and a vibration sensor 1 is set for each steering knuckle to collect the tire vibration data of each wheel.

[0042] The wheels, steering knuckles, wheel actuators 3, and vibration sensors 1 are configured in a one-to-one correspondence. For each wheel, the vehicle noise reduction method of this application is applied for noise reduction. Therefore, different wheel actuators 3 may have different noise reduction frequency signals ultimately executed by the wheel actuators due to the different vibration conditions of their corresponding wheels and the different target frequencies corresponding to the in-vehicle noise data. The noise reduction for a single wheel will be explained later.

[0043] In this embodiment, the wheel actuator 3 is specifically a three-way variable frequency actuator 3; the wheel actuator 3 includes three vibration absorption units; the vibration directions of the three vibration absorption units are orthogonal to each other, such as the vibration directions of the three vibration absorption units corresponding to the X longitudinal direction, Y transverse direction and Z vertical direction respectively; thus, the wheel actuator 3 can achieve noise cancellation at all angles through the combined action of the three vibration absorption units with different vibration directions.

[0044] The vibration absorption unit consists of a mass block, a damper, and a variable stiffness spring. The stiffness of the variable stiffness spring can be dynamically adjusted by a control object such as a piezoelectric ceramic stack, a magnetorheological elastomer, or other smart materials. Adjusting the piezoelectric ceramic stack by current or the magnetorheological elastomer by magnetic field can achieve continuous frequency variation and improve control accuracy. The stiffness of the variable stiffness spring is adjusted by the data processing module 4 controlling the control object.

[0045] By controlling the stiffness of the variable stiffness spring in the vibration absorption unit, the frequency of the vibration absorption unit can be controlled; specifically:

[0046] Where f is the frequency of the vibration absorption unit; k is the stiffness of the variable spring; M is the weight of the mass block; since the weight of the mass block remains constant after the setting is completed, the frequency of the vibration absorption unit can be adjusted by adjusting the stiffness of the variable spring.

[0047] Furthermore, the wheel actuator 3 also includes a self-powered unit; the self-powered unit includes a piezoelectric power generation unit; the power output terminal of the piezoelectric power generation unit is connected to the power supply terminal of the vibration sensor 1 and the power supply terminal of the wheel actuator 3, respectively.

[0048] Both the vibration sensor 1 and the wheel actuator 3 are active devices; therefore, they need to be powered. In some embodiments, a power line can be drawn from the vehicle system to power the vibration sensor 1 and the wheel actuator 3; however, this method has a high modification cost. In this embodiment, a self-powered unit is integrated into the wheel actuator 3 to generate electricity and power the vibration sensor 1 and the wheel actuator 3.

[0049] The self-powered unit specifically includes a piezoelectric power generation unit. The specific type of the piezoelectric power generation unit can be set according to actual needs, such as a piezoelectric cantilever beam. The piezoelectric cantilever beam can convert vibrational mechanical energy into electrical energy. Therefore, when the wheel vibrates or the wheel actuator 3 vibrates, the piezoelectric cantilever beam can generate electricity based on the vibration, thereby powering the vibration sensor 1 and the wheel actuator 3. Specifically:

[0050] Where P is the output power of the piezoelectric cantilever beam; η is the energy conversion efficiency; F(t) is the dynamic force on the piezoelectric cantilever beam; v(t) is the vibration velocity of the piezoelectric cantilever beam; and T is the integration time window.

[0051] To achieve a more stable power supply, energy storage devices such as capacitors and batteries can be installed to maintain the power supply to the vibration sensor 1 and the wheel actuator 3 when the vehicle is stationary. Similarly, since the wheel actuator 3 only reduces noise when the wheel vibrates, energy storage devices may not be required to reduce costs. In other embodiments, a self-functioning unit and the vehicle power supply can be installed simultaneously to power the wheel actuator 3 and the vibration sensor 1.

[0052] Furthermore, in the second embodiment of the vehicle noise reduction method of the present invention based on the first embodiment, step S20 includes the following steps: Step S21: Obtain multiple directional sub-data from the tire vibration data, wherein each directional sub-data corresponds to a vibration direction, and the vibration directions are orthogonal to each other; Step S22: For each of the directional sub-data, perform coherence analysis on the directional sub-data and the in-vehicle noise data to determine the target frequency sub-signal in the directional sub-data; Step S23: Generate the target frequency signal containing each of the target frequency sub-signals.

[0053] The directional data represents the vibration components in a specific direction; the vibration sensor specifically monitors the three-axis vibration of the wheel to obtain three directional data corresponding to the X-axis, Y-axis, and Z-axis.

[0054] It is immediately apparent that, depending on the specific vibration scenario, the signal distribution of wheel vibration varies in different vibration directions. For example, the steering knuckle itself has different transmission characteristics for vibrations in different directions, such as a higher transmission rate for vibrations in the X-axis direction, thus easily amplifying X-axis vibrations. Furthermore, vibrations generated under different driving scenarios will also have different directional tendencies. For instance, uneven road surfaces cause the vehicle to bounce up and down, resulting in more vertical vibration components, while turning causes more lateral vibration components. Therefore, noise reduction needs to be performed separately for the three vibration directions.

[0055] For each direction sub-data, coherence analysis is performed between it and the in-vehicle noise data to obtain the target frequency sub-signal corresponding to that direction sub-data; it is understood that the target frequency sub-signals corresponding to the three direction sub-data are not necessarily the same.

[0056] In this embodiment, by determining the target frequency word signal in multiple directions respectively, the target frequency signal can be accurately determined based on the different directional components.

[0057] Furthermore, in the third embodiment of the vehicle noise reduction method of the present invention based on the first embodiment, step S40 includes the following steps: Step S41: Obtain the noise reduction sub-signal corresponding to each vibration direction in the noise reduction frequency signal, wherein the noise reduction sub-signal is out of phase with the target frequency sub-signal corresponding to the same vibration direction; Step S42: For each noise reduction sub-signal, determine the corresponding vibration absorption unit according to the corresponding vibration direction. The wheel actuator includes multiple vibration absorption units, each vibration absorption unit corresponds to a different vibration direction, and the vibration directions corresponding to each vibration absorption unit are orthogonal to each other. Step S43: Control each of the vibration absorption units to vibrate with the corresponding noise reduction sub-signal.

[0058] A noise reduction sub-signal is generated for each target frequency sub-signal; the corresponding noise reduction sub-signal has the same amplitude but opposite phase as the target frequency signal.

[0059] Once the noise reduction sub-signals are determined, the wheel actuator can be controlled to vibrate based on each noise reduction sub-signal.

[0060] Specifically, the vibration direction corresponding to the noise reduction sub-signal is the same as that of the target frequency sub-signal; the vibration absorption unit with the same vibration direction is controlled based on the noise reduction sub-signal; for example, the noise reduction sub-signal corresponding to the X-axis vibration direction is used to control the vibration of the vibration absorption unit corresponding to the X-axis vibration direction; the same applies to the Y and Z axes. The subsequent target frequency signal will be explained using the determination of one target sub-frequency signal as an example, and each target sub-frequency will be determined separately.

[0061] By controlling the vibration absorption unit in the corresponding vibration direction in the wheel actuator through the noise reduction sub-signal, the precision of noise reduction can be improved to the single vibration direction of a single wheel, thereby improving the effectiveness of noise reduction.

[0062] Furthermore, in the fourth embodiment of the vehicle noise reduction method of the present invention based on the first embodiment of the present invention, step S20 includes the following steps: Step S24: Perform a fast Fourier transform on the tire vibration data to obtain a first frequency signal, and perform a fast Fourier transform on the in-vehicle noise data to obtain a second frequency signal. Step S25: Calculate the first auto-power spectral density corresponding to each frequency in the first frequency signal, and calculate the second auto-power spectral density corresponding to each frequency in the second frequency signal. Step S26: Calculate the cross-power spectral density of the first frequency signal and the second frequency signal at each frequency; Step S27: Calculate the coherence intensity corresponding to each frequency using the first self-power spectral density, the second self-power spectral density, and the cross-power spectral density. Step S28: Determine the target frequency signal with the greatest coherence intensity from the tire vibration data.

[0063] The tire vibration data and the vehicle interior noise data are converted to the frequency domain using FFT (Fast Fourier Transform) to obtain the first frequency signal corresponding to the tire vibration data and the second frequency signal corresponding to the vehicle interior noise data.

[0064] In this embodiment, the coherence between the first frequency signal and the second frequency signal at a specific frequency is calculated based on the power spectral density.

[0065] The power spectral density is the energy distribution of a signal at a specific frequency; for example, the energy distribution of a tire vibration signal at 200 Hz.

[0066] Cross-power spectral density is the joint frequency characteristic of two signals at a specific frequency, which reflects the mutual relationship between the two signals at the frequency.

[0067] Coherence intensity includes:

[0068] Where H(f) represents the coherence intensity between tire vibration data and in-vehicle noise data at frequency f; G ap (f) represents the cross-power spectral density at frequency f; G aa (f) represents the self-power spectral density of the first frequency signal at frequency f; G pp (f) represents the autopower spectral density of the second frequency signal at frequency f.

[0069] After obtaining the coherence intensity corresponding to all frequencies, the frequency with the highest coherence intensity is taken as the target frequency signal; thus, the frequency that makes the greatest contribution to the in-vehicle noise is determined as the target frequency signal.

[0070] Furthermore, in the fifth embodiment of the vehicle noise reduction method of the present invention based on the first embodiment, step S40 includes the following steps: Step S44: Determine the target noise reduction frequency corresponding to the noise reduction frequency signal; Step S45: Obtain the hardware parameters of the wheel actuator; Step S46: Determine the target stiffness based on the target noise reduction frequency and the hardware parameters; Step S47: Send a control signal indicating the target stiffness to the wheel actuator so that the wheel actuator vibrates with the target stiffness to generate the noise reduction frequency signal.

[0071] The hardware parameters are vibration-related parameters in the wheel actuator; for example, the wheel actuator in this embodiment is a three-way variable frequency actuator; the wheel actuator includes three vibration absorption units; the vibration directions of the three vibration absorption units are orthogonal to each other, such as the vibration directions of the three vibration absorption units corresponding to the X longitudinal direction, Y transverse direction and Z vertical direction respectively; thus, the wheel actuator can achieve noise cancellation at all angles through the combined action of the three vibration absorption units with different vibration directions.

[0072] The vibration absorption unit consists of a mass block, a damper, and a variable stiffness spring. The stiffness of the variable stiffness spring can be dynamically adjusted by a control object such as a piezoelectric ceramic stack, a magnetorheological elastomer, or other smart materials. The stiffness of the variable stiffness spring is adjusted by the data processing module controlling the control object.

[0073] By controlling the stiffness of the variable stiffness spring in the vibration absorption unit, the frequency of the vibration absorption unit can be controlled; specifically:

[0074] Where f is the frequency of the vibration absorption unit; k is the stiffness of the variable spring; and M is the weight of the mass block. Since the weight of the mass block remains constant after setting, the frequency of the vibration absorption unit can be adjusted by adjusting the stiffness of the variable spring. The weight of the mass block is a hardware parameter of the wheel actuator.

[0075] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0076] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0077] The present invention also proposes a vehicle comprising the vehicle noise reduction system as described in any of the preceding claims.

[0078] The present invention also proposes a computer-readable storage medium storing a computer program thereon. The computer-readable storage medium may be a memory, or at least one of ROM (Read-Only Memory) / RAM (Random Access Memory), magnetic disk, and optical disk. The computer-readable storage medium includes several instructions to cause a terminal device with a processor (which may be a television, automobile, mobile phone, computer, server, terminal, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0079] In this invention, the terms "first," "second," "third," "fourth," and "fifth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0080] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0081] Although embodiments of the present invention have been shown and described above, the scope of protection of the present invention is not limited thereto. It is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, and substitutions to the above embodiments within the scope of the present invention, and such changes, modifications, and substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A vehicle noise reduction method, characterized in that, The vehicle noise reduction method includes: Acquire tire vibration data and vehicle interior noise data; A coherence analysis is performed on the tire vibration data and the vehicle interior noise data to determine the target frequency signal in the tire vibration data, wherein the target frequency signal is the frequency signal in the tire vibration data that has the maximum coherence with the vehicle interior noise data. Determine the noise reduction frequency signal corresponding to the target frequency signal, wherein the noise reduction frequency signal is out of phase with the target frequency signal; The wheel actuators of the vehicle are controlled to vibrate at the noise-reducing frequency signal, and the wheel actuators are located at the horns of the vehicle.

2. The vehicle noise reduction method as described in claim 1, characterized in that, The step of performing coherence analysis on the tire vibration data and the in-vehicle noise data to determine the target frequency signal in the tire vibration data includes: Multiple directional sub-data points are obtained from the tire vibration data, wherein each directional sub-data point corresponds to a vibration direction, and the vibration directions are orthogonal to each other; For each of the aforementioned directional sub-data, a coherence analysis is performed between the directional sub-data and the in-vehicle noise data to determine the target frequency sub-signal in the directional sub-data; Generate the target frequency signal that includes each of the target frequency sub-signals.

3. The vehicle noise reduction method as described in claim 1, characterized in that, The wheel actuator controlling the vehicle vibrates with the noise-reducing frequency signal, and the wheel actuator is disposed at the steering knuckle of the vehicle, comprising: Obtain the noise reduction sub-signal corresponding to each vibration direction in the noise reduction frequency signal, wherein the noise reduction sub-signal is out of phase with the target frequency sub-signal corresponding to the same vibration direction; For each noise reduction sub-signal, a corresponding vibration absorption unit is determined according to the corresponding vibration direction. The wheel actuator includes multiple vibration absorption units, each vibration absorption unit corresponds to a different vibration direction, and the vibration directions of each vibration absorption unit are orthogonal to each other. Each of the vibration-absorbing units is controlled to vibrate according to the corresponding noise-reducing sub-signal.

4. The vehicle noise reduction method as described in claim 1, characterized in that, The step of performing coherence analysis on the tire vibration data and the in-vehicle noise data to determine the target frequency signal in the tire vibration data includes: The tire vibration data is subjected to a fast Fourier transform to obtain a first frequency signal, and the in-vehicle noise data is subjected to a fast Fourier transform to obtain a second frequency signal. Calculate the first auto-power spectral density corresponding to each frequency in the first frequency signal, and calculate the second auto-power spectral density corresponding to each frequency in the second frequency signal; Calculate the cross-power spectral density of the first frequency signal and the second frequency signal at each frequency; The coherence intensity corresponding to each frequency is calculated using the first self-power spectral density, the second self-power spectral density, and the cross-power spectral density. The target frequency signal with the highest coherence intensity is determined from the tire vibration data.

5. The vehicle noise reduction method as described in claim 1, characterized in that, The wheel actuator controlling the vehicle vibrates with the noise-reducing frequency signal, and the wheel actuator is disposed at the steering knuckle of the vehicle, comprising: Determine the target noise reduction frequency corresponding to the noise reduction frequency signal; Obtain the hardware parameters of the wheel actuator; The target stiffness is determined based on the target noise reduction frequency and the hardware parameters. A control signal indicative of the target stiffness is sent to the wheel actuator to cause the wheel actuator to vibrate at the target stiffness to generate the noise reduction frequency signal.

6. A vehicle noise reduction system, characterized in that, The vehicle noise reduction system is applied to any one of claims 1 to 5; the vehicle noise reduction system includes a vibration sensor, a noise sensor, a data processing module, and a wheel actuator; wherein the vibration sensor and the wheel actuator are disposed at the steering knuckle of the vehicle, and the noise sensor is disposed in the passenger space of the vehicle; the data acquisition terminal of the data processing module is connected to the vibration sensor and the noise sensor respectively, and the output terminal of the data processing module is connected to the control terminal of the wheel actuator.

7. The vehicle noise reduction system as described in claim 6, characterized in that, The wheel actuator is installed on each steering knuckle of the vehicle; the wheel actuator includes multiple vibration absorption units, each vibration absorption unit corresponds to a different vibration direction, and the vibration directions of each vibration absorption unit are orthogonal to each other; the control terminal of each vibration absorption unit is connected to the output terminal of the data processing module.

8. The vehicle noise reduction system as described in claim 6, characterized in that, The wheel actuator also includes a self-powered unit; the self-powered unit includes a piezoelectric power generation unit; the power output terminal of the piezoelectric power generation unit is connected to the power supply terminal of the vibration sensor and the power supply terminal of the wheel actuator, respectively.

9. A vehicle, characterized in that, The vehicle includes a vehicle noise reduction system as described in any one of claims 6 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the vehicle noise reduction method as described in any one of claims 1 to 5.

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