Commercial vehicle wind noise active noise reduction method and system and commercial vehicle

Abstract

The invention relates to the technical field of vehicle active noise reduction, in particular to a commercial vehicle wind noise active noise reduction method and system and a commercial vehicle. The method comprises the steps that signals are collected through a vibration sensor array arranged in a wind noise sensitive area outside a cab, and a wind noise mode and a leading noise source are recognized; synthesizing an in-vehicle prediction noise signal based on the dominant noise source vibration signal and a pre-stored sound transfer function; passenger distribution is detected through a gravity sensing module, and a target noise reduction area and a corresponding mode are determined; with the prediction signal as a reference and in combination with feedback of an error microphone, an active noise reduction controller operates an adaptive algorithm to generate a control signal; and finally, counteracting sound waves are generated in the target area through the loudspeaker array, so that effective counteracting of the wind noise is realized. According to the invention, closed-loop intelligent control from noise source identification, passenger perception to region precise offset is realized, and the system has the characteristics of fast response, high energy efficiency and excellent noise reduction effect.

Description

Technical Field

[0001] This application relates to the field of active noise reduction technology for vehicles, specifically to a method, system, and commercial vehicle for active wind noise reduction. Background Technology

[0002] With the increasing demands for NVH performance from heavy-duty truck drivers and passengers, active noise cancellation technology has become an important means of improving the sound quality inside the cab. Currently, research and application of this technology mainly focus on controlling road noise and engine noise. However, due to the square shape and large frontal area of ​​commercial vehicle cabs, wind noise can replace other noises as the main noise source in the cab during high-speed driving or in high crosswind environments, seriously affecting driving comfort.

[0003] Traditional active noise cancellation systems typically rely on feedback signals from in-vehicle error microphones for delayed adjustments. Their response speed is ill-suited to the rapidly changing nature of wind noise, resulting in poor noise reduction and low energy efficiency. Furthermore, existing systems generally lack the ability to intelligently identify noise sources and the distribution of occupants within the cabin, failing to achieve precise regional noise reduction. They often treat the entire cabin space indiscriminately, leading to energy waste and failing to meet the personalized acoustic environment needs of occupants in different seats.

[0004] Therefore, there is an urgent need in this field for an active noise reduction system that can respond quickly, accurately locate wind noise sources, and intelligently adjust noise reduction strategies according to the actual occupant situation, so as to effectively solve the noise problem of commercial vehicles in complex wind field environments and improve the driving experience. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a method, system, and commercial vehicle for active wind noise reduction in commercial vehicles, resolving the problem of significant wind noise in the driver's cab when the vehicle is traveling at high speeds and the external wind speed is high.

[0006] In a first aspect, the present invention provides a method for active wind noise reduction in commercial vehicles, comprising the following steps: S1. Collect wind noise vibration signals by means of a vibration sensor array deployed in the wind noise sensitive area on the outer surface of the cab; determine the current wind noise mode and identify the dominant wind noise source based on the vibration signals; the wind noise sensitive area includes the windshield, rearview mirror, A-pillar, blind spot mirror, cab fairing and door glass area; S2. Based on the vibration signal of the dominant wind noise source and the pre-stored acoustic transfer function from the location of the dominant wind noise source to one or more preset noise reduction points in the driver's cab, a predicted noise signal is synthesized. S3. The occupant distribution status is detected by a gravity sensing module installed on the driver's seat and / or sleeper berth in the driver's cab, and the target noise reduction area and corresponding noise reduction mode to be actively noise-reduced are determined based on the distribution status; the target noise reduction area includes one or more noise reduction points; S4. The predicted noise signal is used as a reference signal and input to the active noise cancellation controller. The active noise cancellation controller runs an adaptive noise cancellation algorithm based on the noise cancellation mode, the reference signal, and the residual noise signal from the error microphone set in the target noise cancellation area to generate control signals for driving the speaker array. S5. The speaker array emits canceling sound waves according to the control signal to cancel wind noise in the target noise reduction area.

[0007] By directly acquiring wind noise vibration signals through a vibration sensor array deployed in external wind noise-sensitive areas, the problem of traditional ANC systems being insensitive to wind noise and having poor control performance is solved by addressing the noise source.

[0008] By synthesizing predicted noise signals using pre-stored acoustic transfer functions, the system provides a forward-looking reference signal, overcoming the lag inherent in traditional systems that rely on error microphone feedback, and enabling the system to respond quickly to rapidly changing wind noise.

[0009] By determining the target noise reduction area and mode based on the occupant distribution, on-demand noise reduction is achieved, avoiding energy waste in vacant areas and improving the system's energy utilization efficiency.

[0010] As a further limitation of the technical solution of the present invention, in S1, the step of determining the current wind noise mode and identifying the dominant wind noise source specifically includes: The vibration amplitude of the sensor signals located in different wind noise sensitive areas of the vibration sensor array is compared in real time. If the vibration amplitude of the sensor signal located in the windshield area is greater than the vibration amplitude of the sensor signal located in the door glass area than the first preset threshold, then it is determined that the current mode is windward and the windshield area is identified as the dominant wind noise source. If the vibration amplitude of the sensor signal located in the door glass area is greater than the vibration amplitude of the sensor signal located in the windshield area than the second preset threshold, then the current mode is determined to be crosswind mode, and the door glass area is identified as the dominant wind noise source. If the difference in vibration amplitude between the sensor signals in each wind noise sensitive area is less than the third preset threshold, then the current mode is determined to be downwind, and multiple wind noise sensitive areas are identified as the dominant wind noise source.

[0011] By comparing the amplitude relationships of sensor signals in a specific area and setting thresholds, the system achieves objective and automatic identification of windward, crosswind, and tailwind patterns. The judgment logic is clear and reliable, with strong anti-interference capabilities. Accurate identification of the dominant wind noise source ensures that the system can concentrate limited computational and acoustic resources on controlling the main noise source.

[0012] As a further limitation of the technical solution of the present invention, in S2, the step of synthesizing the predicted noise signal based on the vibration signal of the dominant wind noise source and the pre-stored acoustic transfer function specifically includes: S21: From the pre-stored sound transfer function database, call the noise transfer function corresponding to the currently identified dominant wind noise source location and the one or more preset noise reduction sites; S22: In the frequency domain, the vibration signal of the dominant wind noise source is convolved with the noise transfer function called to calculate the predicted sound pressure signal of the wind noise transmitted to each preset noise reduction point. S23: Based on the predicted sound pressure signal, synthesize a time-domain predicted noise signal containing frequency, amplitude, and phase information.

[0013] The synthesized time-domain predictive noise signal contains complete amplitude and phase information, providing crucial input conditions for the subsequent generation of high-precision antiphase acoustic waves.

[0014] As a further limitation of the technical solution of the present invention, in S22, the specific steps of convolving the vibration signal of the dominant wind noise source with the called noise transfer function in the frequency domain include: S22a. Perform a fast Fourier transform on the time-domain vibration signal of the dominant wind noise source to obtain its frequency domain representation; S22b. In the frequency domain, the frequency domain representation of the vibration signal and the frequency domain representation of the noise transfer function are multiplied by a complex number to obtain the frequency domain representation of the predicted sound pressure signal.

[0015] In S23, the specific steps for synthesizing a time-domain predicted noise signal containing frequency, amplitude, and phase information based on the predicted sound pressure signal include: S23a. Perform a fast inverse Fourier transform on the frequency domain representation of the predicted sound pressure signal to obtain the initial time domain predicted noise signal. S23b. The initial time-domain prediction noise signal is amplitude normalized and / or delay compensated to adapt to the input requirements of the active noise cancellation controller, and a final time-domain prediction noise signal is generated for use as a reference signal.

[0016] Fast Fourier Transform (FFT) is used to perform convolution in the frequency domain via complex multiplication, which is computationally more efficient than time-domain convolution, meeting the real-time requirements of the vehicle system. Amplitude normalization adapts the signal to the controller's dynamic range, and delay compensation eliminates the lag caused by the system processing link, ensuring accurate synchronization between the predicted signal and the real noise in the time domain, thus guaranteeing the final anti-phase cancellation effect.

[0017] As a further limitation of the technical solution of the present invention, in S3, the step of detecting the occupant distribution state through the gravity sensing module and determining the target noise reduction area and the corresponding noise reduction mode that need to be performed on the active noise reduction according to the distribution state includes: S31. Real-time reading of signals from gravity sensor modules in the driver's seat, passenger seat, and sleeper berth; S32. Compare the signal with a preset weight threshold to determine whether there is a passenger at the corresponding location; S33. Based on the judgment result of the occupant presence status, map it to a predefined noise reduction mode, and determine the target noise reduction region activated by the noise reduction mode: If only the driver's seat is identified as having occupants, then the noise reduction mode is mapped to the driver's seat, and the target noise reduction area is determined to be the driver's seat area. The noise reduction points contained in the driver's seat area are activated. If both the driver's seat and the passenger seat are determined to be occupied, the noise reduction mode is mapped to the driver and passenger seats, and the target noise reduction areas are determined to be the driver area and the passenger area. The noise reduction points contained in the driver area and the passenger area are activated. If both the driver's seat and the sleeper berth are determined to be occupied, the noise reduction mode is mapped to the driver's seat and sleeper berth, and the target noise reduction areas are determined to be the driver's seat area and the sleeper berth area. The noise reduction points contained in the driver's seat area and the sleeper berth area are activated.

[0018] By setting a preset weight threshold, it can accurately determine whether there are occupants in the seats / berths, avoiding accidental switching of noise reduction modes due to items being placed there, and ensuring that the noise reduction area perfectly matches the actual occupant position. A direct mapping is established between occupant presence, noise reduction mode, and target noise reduction area, eliminating the need for complex logic checks, shortening mode switching time, and ensuring rapid adaptation of the noise reduction area when occupants change.

[0019] By activating only the noise reduction points within the target noise reduction area, error microphones and speaker resources can be concentrated in areas with occupants, avoiding interference from invalid signals in non-occupant areas, and improving the noise reduction accuracy and sound quality improvement of the target area.

[0020] As a further limitation of the technical solution of the present invention, in S4, the active noise cancellation controller performs the following operations: S41. Based on the current noise reduction mode, call the secondary path transfer function model corresponding to the activated target noise reduction region; the secondary path transfer function model pre-stores the acoustic path characteristics from the speaker array to the error microphone in the target noise reduction region; S42. Using the predicted noise signal as a reference signal and the residual noise signal from the error microphone in the target noise reduction area as the error signal, run the Filter-X Least Mean Square Adaptive Algorithm; the execution of the algorithm includes: An adaptive filter with adjustable coefficients is used to filter the signal and generate an initial control signal. The initial control signal is sent to the secondary path transfer function model to obtain the filtered signal; The error correlation signal is calculated based on the filtered signal and the residual noise signal. The coefficients of the adaptive filter are updated using the LMS algorithm based on the error correlation signal to minimize the mean square value of the residual noise signal. S43. The control signal obtained after real-time processing by the adaptive filter is output to the speaker array corresponding to the current noise reduction mode.

[0021] Pre-stored secondary path transfer functions for speakers and error microphones compensate for amplitude attenuation and phase shift during sound wave radiation from the speakers to the error microphones, avoiding waveform distortion caused by secondary path characteristics and improving noise reduction performance. Real-time updates of adaptive filter coefficients minimize the mean square value of residual noise, dynamically responding to frequency and amplitude variations in wind noise and preventing noise reduction attenuation when fixed filter coefficients are used in response to changing operating conditions. Control signals are only output to speakers in the target noise reduction area, avoiding ineffective operation of speakers in non-target areas, reducing power consumption, and preventing sound field interference caused by signal superposition from multiple speaker areas.

[0022] As a further limitation of the technical solution of the present invention, step S5 specifically includes: S51. The control signal generated by the active noise cancellation controller is distributed to the power amplifier that drives one or more speakers in the target noise cancellation area determined according to the current noise cancellation mode. S52. The electrical control signal is amplified by the power amplifier and used to drive the corresponding speaker to vibrate; S53. The driven loudspeaker radiates a sound wave with the same amplitude but opposite phase as the predicted noise signal, which cancels out the original wind noise wave entering the target noise reduction area, thereby reducing the sound pressure level in the target noise reduction area.

[0023] Amplifying the control signal to the appropriate power range for the speaker ensures stable speaker vibration amplitude, preventing insufficient cancellation amplitude due to insufficient signal power or speaker damage due to power overload. By radiating sound waves with the same amplitude but opposite phase, three-dimensional destructive interference is formed within the target noise reduction area, precisely reducing the sound pressure level in that area while avoiding unnecessary sound field disturbances in non-target areas. Directly canceling the original wind noise waves entering the target area through destructive interference, rather than merely masking the noise, fundamentally reduces the wind noise pressure level in the cabin, improving the auditory comfort of passengers.

[0024] In a second aspect, embodiments of the present invention provide a commercial vehicle wind noise active noise reduction system for implementing the method described in the first aspect, the system comprising: A vibration sensor array deployed on the wind noise sensitive area of ​​the outer surface of the cab of a commercial vehicle to collect wind noise vibration signals; Gravity sensor modules are installed in the driver's seat, passenger seat, and sleeper berth within the driver's cab to detect the occupant distribution. Pre-set noise reduction points are placed in the driver's cab to collect residual noise signals after noise reduction; A speaker array distributed throughout the driver's cab; An active noise cancellation controller is communicatively connected to the vibration sensor array, gravity sensing module, error microphone array, and speaker array, and internally stores a sound transfer function database and a secondary path transfer function database. The active noise cancellation controller includes: The wind noise mode determination unit is used to receive the signal from the vibration sensor array, and determine the current wind noise mode and identify the dominant wind noise source based on the vibration amplitude comparison result of each sensor signal. The predictive noise signal synthesis unit is used to synthesize a predictive noise signal based on the vibration signal of the dominant wind noise source and the acoustic transfer function from the location of the dominant wind noise source to the preset noise reduction point, which is called from the acoustic transfer function database. The noise reduction mode matching unit is used to receive the signal from the gravity sensing module and determine the target noise reduction area and the corresponding noise reduction mode that need to be actively noise-reduced according to the occupant distribution state. An adaptive filtering unit is used to take the predicted noise signal as a reference signal, the residual noise signal of the error microphone corresponding to the target noise reduction area as an error signal, and call the secondary path transfer function model corresponding to the current noise reduction mode to run the filter-X minimum mean square adaptive algorithm to generate a control signal for driving the speaker array. The distribution unit is used to distribute the control signal to the loudspeaker corresponding to the target noise reduction area, so as to drive the loudspeaker to emit canceling sound waves.

[0025] The pre-stored acoustic transfer function database (wind noise source - noise reduction site) and secondary path transfer function database (loudspeaker - error microphone) eliminate the need for real-time calibration of transfer characteristics, reducing system startup time and avoiding noise interference during real-time calibration, thus ensuring long-term stable operation of the system.

[0026] Thirdly, the present invention also provides a commercial vehicle equipped with the active wind noise reduction system for commercial vehicles as described in the second aspect.

[0027] As can be seen from the above technical solutions, this application has the following advantages: In response to the problem of high wind noise in commercial vehicles at high speeds or in strong wind environments, the application directly solves the problem of poor sound quality caused by wind noise in the cab through a full-process design of vibration sensing, sound transfer function prediction, and occupant adaptation, thereby improving the driving experience.

[0028] By identifying the distribution of occupants through a gravity sensing module, noise reduction is only performed on the target noise reduction area where occupants are present, avoiding energy waste caused by indiscriminate noise reduction across the entire area; at the same time, based on the dominant wind noise source, targeted cancellation signals are synthesized to reduce ineffective noise reduction actions and lower system energy consumption.

[0029] By introducing an error microphone to collect residual noise signals and combining it with an adaptive algorithm to dynamically correct control parameters, the system can cope with the dynamic characteristics of wind noise as vehicle speed and wind direction change, avoid the effect of fixed parameter noise reduction decay when operating conditions change, and ensure stable noise reduction effect under different driving scenarios.

[0030] By deploying vibration sensors in key wind noise-sensitive areas of commercial vehicles, such as the windshield, rearview mirrors, and A-pillars, wind noise vibration signals can be comprehensively captured. Combined with amplitude comparison, wind noise patterns can be accurately determined, providing a precise basis for subsequent targeted noise reduction. Attached Figure Description

[0031] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart illustrating the method provided in an embodiment of the present invention.

[0033] Figure 2 A block diagram of a system provided in an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of the sensor pre-embedded location in an embodiment of the present invention, wherein... Figure 3 (a) in the image shows the sensor location in the windshield area. Figure 3(b) in the diagram represents the sensor location in the door glass area. Figure 3 (c) in the diagram represents the sensor location in the fairing area above the cab. Detailed Implementation

[0035] To make the purpose, features, and advantages of this application more apparent and understandable, specific embodiments and accompanying drawings will be used to clearly and completely describe the technical solution protected by this application. Obviously, the embodiments described below are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this application and in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0037] like Figure 1 As shown in the figure, this embodiment of the invention provides a method for active wind noise reduction in commercial vehicles, including the following steps: S1. Collect wind noise vibration signals by means of a vibration sensor array deployed in the wind noise sensitive area on the outer surface of the cab; determine the current wind noise mode and identify the dominant wind noise source based on the vibration signals; the wind noise sensitive area includes the windshield, rearview mirror, A-pillar, blind spot mirror, cab fairing and door glass area; IEPE type vibration sensors (model: PCB 352C33) are installed in wind noise-sensitive areas outside the cab. Specific locations are as follows: Figure 3 As shown in (a), (b), and (c), the sensor is connected to the signal acquisition module of the active noise cancellation controller via a shielded cable or wirelessly, with a sampling frequency of 48kHz and a sampling accuracy of 16bit.

[0038] In this step, determining the current wind noise pattern and identifying the dominant wind noise source specifically includes: The vibration amplitude of the sensor signals located in different wind noise sensitive areas of the vibration sensor array is compared in real time. If the vibration amplitude of the sensor signal located in the windshield area is greater than the vibration amplitude of the sensor signal located in the door glass area than the first preset threshold, then it is determined that the current mode is windward and the windshield area is identified as the dominant wind noise source. If the vibration amplitude of the sensor signal located in the door glass area is greater than the vibration amplitude of the sensor signal located in the windshield area than the second preset threshold, then the current mode is determined to be crosswind mode, and the door glass area is identified as the dominant wind noise source. If the difference in vibration amplitude between the sensor signals in each wind noise sensitive area is less than the third preset threshold, then the current mode is determined to be downwind, and multiple wind noise sensitive areas are identified as the dominant wind noise source.

[0039] In real-vehicle road tests, 100 sets of sensor amplitude data were collected under different operating conditions (vehicle speed 60-120km / h, wind speed 0-10m / s), and the threshold was determined through statistical analysis. The first preset threshold is the 95th percentile of the amplitude difference between the windshield and door glass sensors, which is calculated to be 0.6g. The second preset threshold is set to 0.5g, which is the 95th percentile of the amplitude difference between the door glass and windshield sensors. The third preset threshold is the maximum value of the standard deviation of the amplitude of all sensors, set to 0.2g.

[0040] Pattern determination process: Read the real-time amplitude values ​​of all sensors (e.g., windshield 1.3g, door glass 0.6g, A-pillar 0.8g, rearview mirror 0.7g). The amplitude difference between the windshield and the door glass is calculated (0.7g). If it is greater than the first preset threshold of 0.6g, it is initially determined to be a windward mode. The amplitude differences between other sensors (A-pillar 0.8g, rearview mirror 0.7g) and the windshield amplitude (0.5g, 0.6g) were verified to be less than the first preset threshold. It was confirmed that there were no other dominant wind noise sources, and the mode was finally determined to be windward mode, with the windshield as the dominant wind noise source.

[0041] If a sensor signal malfunctions (e.g., the amplitude of a certain sensor is always 0), the controller will automatically use data from an adjacent sensor to replace it (e.g., if the left A-pillar sensor malfunctions, the right A-pillar sensor with an amplitude of 0.7g will be used to replace it), ensuring that the mode judgment is not interrupted.

[0042] S2. Based on the vibration signal of the dominant wind noise source and the pre-stored acoustic transfer function from the location of the dominant wind noise source to one or more preset noise reduction points in the driver's cab, a predicted noise signal is synthesized; specifically including: S21: From the pre-stored acoustic transfer function database, call the noise transfer function corresponding to the currently identified dominant wind noise source location and the one or more preset noise reduction sites; refers to the acoustic transfer characteristic function from a specific wind noise source location outside the commercial vehicle cab (such as windshield, door glass, etc.) to a preset noise reduction site inside the cab (such as the driver's ear, passenger's ear, sleeper head, etc.). When the input signal is the vibration signal at the location of the wind noise source (such as the vibration acceleration of the windshield caused by the impact of airflow) and the output signal is the sound pressure signal at the preset noise reduction point (such as the wind noise pressure level at the driver's ear), the function is VTF (Vibration-Sound Pressure Transfer Function), which means the sound pressure output response at the target point under a unit vibration input. When the input signal is the sound pressure signal at the location of the wind noise source (such as the sound pressure generated by airflow disturbance outside the cab) and the output signal is the sound pressure signal at the preset noise reduction point, this function is NTF (sound pressure-sound pressure transfer function), which physically represents the sound pressure output response at the target point under a unit sound pressure input. The formula is as follows:

[0043] Let be the noise transfer function. This is the frequency domain representation of the input signal. The frequency domain representation of the output signal. This refers to the amplitude-frequency response, which is the ratio of the output amplitude to the input amplitude. This refers to the phase frequency characteristic, which is the phase difference between the output signal and the input signal.

[0044] S22: In the frequency domain, the vibration signal of the dominant wind noise source is convolved with the noise transfer function to calculate the predicted sound pressure signal transmitted to each preset noise reduction point; specifically including: S22a, performing a fast Fourier transform on the time-domain vibration signal of the dominant wind noise source to obtain its frequency domain representation. S22b. In the frequency domain, the frequency domain representation of the vibration signal and the frequency domain representation of the noise transfer function are multiplied by a complex number to obtain the frequency domain representation of the predicted sound pressure signal. S23: Based on the predicted sound pressure signal, synthesize a time-domain predicted noise signal containing frequency, amplitude, and phase information; specifically including: S23a, performing a fast inverse Fourier transform on the frequency domain representation of the predicted sound pressure signal to obtain an initial time-domain predicted noise signal; S23b. The initial time-domain prediction noise signal is amplitude normalized and / or delay compensated to adapt to the input requirements of the active noise cancellation controller, and a final time-domain prediction noise signal is generated for use as a reference signal.

[0045] Amplitude normalization: Ensures that the amplitude of the predicted signal is within the effective input range of the controller.

[0046] Delay compensation: compensates for the minute delays generated during signal calculation and transmission, ensuring that the generated canceled sound wave is precisely aligned with the original noise.

[0047] During the system development phase, the acoustic transfer function (NTF / VTF) of the dominant wind noise source location to the preset noise reduction point was calibrated in a semi-anechoic chamber using the LMS Test.Lab acoustic testing system. Taking the windshield as an example, a sinusoidal sweep vibration was applied to the windshield using an exciter, while a microphone was placed at the driver's ear position (30cm above the seat back and 15cm horizontally from the center of the seat) to collect sound pressure signals. The acoustic transfer function from the windshield to the driver's ear was calculated and stored in the controller's acoustic transfer function database. The controller calls the acoustic transfer function corresponding to the current dominant wind noise source and the preset noise reduction point, and performs a convolution operation between the vibration signal collected by the windshield sensor and the transfer function to synthesize the predicted noise signal at the driver's ear position. In this embodiment, this can be a signal with a sound pressure level of 85dB(A) and a phase of 0° in the 200Hz frequency band. The calibration steps of the noise transfer function are as follows: A piezoelectric vibrator is attached to a designated location on the windshield to apply controlled vibration input; A high-precision condenser microphone is placed at a preset noise reduction point in the driver's seat to collect sound pressure output; Connect to the LMS Test.Lab acoustic testing system to synchronously acquire the vibration signal of the exciter (input) ) and the microphone's sound pressure signal (output) ).

[0048] A sinusoidal sweep frequency excitation is applied to the windshield using a vibrator, with a frequency range of 20-2000Hz and a sweep rate of 1oct / min. The excitation vibration amplitude is controlled between 0.1-1g (to avoid excessive vibration that could damage the cab structure). The LMS system synchronously acquires the vibration acceleration signal (time domain) of the exciter and the sound pressure signal (time domain) of the microphone at a sampling frequency of 48kHz, and converts both into frequency domain spectra. (Vibrational acceleration spectrum) and (sound pressure spectrum); According to the formula The amplitude-frequency response of the windshield-driver's ear position at each frequency point from 20 to 2000 Hz was calculated. Phase frequency characteristics ; Repeat the test three times, and take the average of the three results as the final transfer function to eliminate random errors. Store this function in the acoustic transfer function database of the active noise cancellation controller according to the unique identifier of the wind noise source location - preset noise reduction point for subsequent real-time calls.

[0049] S3. Using gravity sensing modules installed on the driver's seat and / or sleeper berth, detect the occupant distribution status and determine the target noise reduction area and corresponding noise reduction mode for active noise cancellation based on the distribution status; the target noise reduction area includes one or more noise reduction points; this step specifically includes: S31. Real-time reading of signals from gravity sensor modules on the driver's seat, passenger seat, and sleeper berth; one piezoresistive gravity sensor (model: Flintec PB3) is installed under the driver's seat cushion, under the passenger seat cushion, and in the middle of the sleeper berth. The sensor range is 0-200kg and communicates with the controller via CAN bus.

[0050] S32. Compare the signal with a preset weight threshold to determine whether there is a passenger at the corresponding location; S33. Based on the judgment result of the occupant presence status, map it to a predefined noise reduction mode, and determine the target noise reduction region activated by the noise reduction mode: If only the driver's seat is identified as having an occupant, the noise reduction mode is mapped to the driver's seat, and the target noise reduction area is determined to be the driver's seat area. The noise reduction points contained in the driver's seat area are activated; here, the target noise reduction area is around the driver's ear. space; If both the driver's seat and the passenger seat are determined to be occupied, the noise reduction mode is mapped to the driver and passenger seats, and the target noise reduction areas are determined to be the driver area and the passenger area. The noise reduction points contained in the driver area and the passenger area are activated. If both the driver's seat and the sleeper berth are determined to be occupied, the noise reduction mode is mapped to the driver's seat and sleeper berth, and the target noise reduction areas are determined to be the driver's seat area and the sleeper berth area. The noise reduction points contained in the driver's seat area and the sleeper berth area are activated.

[0051] S4. The predicted noise signal is used as a reference signal and input to the active noise cancellation controller. Based on the noise cancellation mode, the reference signal, and the residual noise signal from the error microphone set in the target noise cancellation area, the active noise cancellation controller runs an adaptive noise cancellation algorithm to generate control signals for driving the speaker array. In this step, the active noise cancellation controller performs the following operations: S41. Based on the current noise reduction mode, call the secondary path transfer function model corresponding to the activated target noise reduction region; the secondary path transfer function model pre-stores the acoustic path characteristics from the speaker array to the error microphone in the target noise reduction region; During the system development phase, the secondary path transfer function of the speaker-error microphone was calibrated through real vehicle testing: a sweep frequency signal was played on the driver's dashboard speaker, and a signal was simultaneously collected at the driver's ear error microphone. The secondary path transfer function from the speaker to the error microphone was calculated and stored in the secondary path database. The active noise cancellation controller calls two sets of secondary path models according to the driver's sleeper mode: ① driver's dashboard speaker → driver's error microphone; ② sleeper head speaker → sleeper error microphone.

[0052] S42. Using the predicted noise signal as a reference signal and the residual noise signal from the error microphone in the target noise reduction area as the error signal, run the Filter-X Least Mean Square Adaptive Algorithm; the execution of the algorithm includes: An adaptive filter with adjustable coefficients is used to filter the signal and generate an initial control signal. The initial control signal is sent to the secondary path transfer function model to obtain the filtered signal; The error correlation signal is calculated based on the filtered signal and the residual noise signal. Using this error correlation signal, the coefficients of the adaptive filter are updated using the LMS algorithm to minimize the mean square value of the residual noise signal. The formula for the coefficients of the adaptive filter is as follows:

[0053] In the formula, This represents the coefficient vector of the adaptive filter at the next time step; This represents the coefficient vector of the adaptive filter at the current time. This is the preset convergence step size, used to control the convergence speed and stability of the algorithm; This represents the residual noise signal collected at the current moment; This represents the filtered signal obtained by filtering through the secondary path transfer function model at the current moment.

[0054] Repeat the above steps every 2ms until the residual noise signal stabilizes (e.g., the mean square value change over 10 consecutive samples is less than 10%). ).

[0055] S43. The control signal obtained after real-time processing by the adaptive filter is output to the speaker array corresponding to the current noise reduction mode. Specifically, the active noise cancellation controller distributes the optimized control signal according to the region: Driver's area: The control signal is 200Hz, 85dB (A), phase 180°, and output to the power amplifier of the driver's dashboard speaker; Sleeper area: The control signal is 180Hz, 82dB (A), phase 180°, and output to the power amplifier of the sleeper head speaker.

[0056] S5. A speaker array emits canceling sound waves according to the control signal to cancel wind noise within the target noise reduction area. This step specifically includes: S51. The control signal generated by the active noise cancellation controller is distributed to the power amplifier that drives one or more speakers in the target noise cancellation area determined according to the current noise cancellation mode. Two Class D power amplifiers (model: TI TAS5825M) are installed inside the center console of the cab. Each channel has a rated output power of 20W and supports 4Ω load, corresponding to the driver's and passenger's speakers respectively. S52. The electrical control signal is amplified by the power amplifier and the corresponding speaker is driven to vibrate; the gain of the driver's amplifier is set to 20dB and the gain of the passenger's amplifier is set to 18dB (adjusted according to the difference in speaker sensitivity, the driver's speaker sensitivity is 92dB and the passenger's is 94dB). The power amplifier amplifies the low-level control signal output by the active noise cancellation controller into a high-power signal, driving the speaker to vibrate.

[0057] S53. The driven loudspeaker radiates a sound wave with the same amplitude but opposite phase as the predicted noise signal, which cancels out the original wind noise wave entering the target noise reduction area, thereby reducing the sound pressure level in the target noise reduction area.

[0058] This invention also provides a commercial vehicle wind noise active noise reduction system for implementing the methods described in the above embodiments, the system comprising: A vibration sensor array deployed on the wind noise sensitive area of ​​the outer surface of the cab of a commercial vehicle to collect wind noise vibration signals; Gravity sensor modules are installed in the driver's seat, passenger seat, and sleeper berth within the driver's cab to detect the occupant distribution. Pre-set noise reduction points are placed in the driver's cab to collect residual noise signals after noise reduction; A speaker array distributed throughout the driver's cab; An active noise cancellation controller is communicatively connected to the vibration sensor array, gravity sensing module, error microphone array, and speaker array, and internally stores a sound transfer function database and a secondary path transfer function database. The active noise cancellation controller includes: The wind noise mode determination unit is used to receive the signal from the vibration sensor array, and determine the current wind noise mode and identify the dominant wind noise source based on the vibration amplitude comparison result of each sensor signal. The predictive noise signal synthesis unit is used to synthesize a predictive noise signal based on the vibration signal of the dominant wind noise source and the acoustic transfer function from the location of the dominant wind noise source to the preset noise reduction point, which is called from the acoustic transfer function database. The noise reduction mode matching unit is used to receive the signal from the gravity sensing module and determine the target noise reduction area and the corresponding noise reduction mode that need to be actively noise-reduced according to the occupant distribution state. An adaptive filtering unit is used to take the predicted noise signal as a reference signal, the residual noise signal of the error microphone corresponding to the target noise reduction area as an error signal, and call the secondary path transfer function model corresponding to the current noise reduction mode to run the filter-X minimum mean square adaptive algorithm to generate a control signal for driving the speaker array. The distribution unit is used to distribute the control signal to the loudspeaker corresponding to the target noise reduction area, so as to drive the loudspeaker to emit canceling sound waves.

[0059] In some embodiments, the wind noise mode determination unit is configured to determine the wind noise mode in the following manner: Compare the sensor signal amplitude located in the windshield area with the sensor signal amplitude located in the door glass area; If the signal amplitude at the windshield is greater than the first preset threshold compared to the door glass, it is determined to be a windward mode, and the main wind noise source is the windshield area. If the signal amplitude at the door glass is greater than the second preset threshold compared to the windshield, it is determined to be crosswind mode, and the main wind noise source is the door glass area. If the difference in signal amplitude in each area is less than the third preset threshold, it is determined to be a downwind mode, and the main wind noise source is multiple areas.

[0060] In some embodiments, the prediction noise signal synthesis unit is configured to synthesize the prediction noise signal in the following manner: Call the corresponding noise transfer function from the sound transfer function database; In the frequency domain, the frequency domain representation of the vibration signal of the dominant wind noise source is multiplied by the frequency domain representation of the noise transfer function to obtain the frequency domain representation of the predicted sound pressure signal. The time-domain predicted noise signal is generated by performing an inverse fast Fourier transform on the frequency domain representation of the predicted sound pressure signal and then performing amplitude normalization and / or delay compensation.

[0061] In some embodiments, the noise reduction mode matching unit is configured to determine the noise reduction mode in the following manner: If only the driver's seat gravity sensor module responds, then the driver's seat noise reduction mode is activated, with the target noise reduction area being the driver's seat area. If the gravity sensor modules of both the driver's seat and the passenger seat respond, the driver and passenger noise reduction mode will be activated, with the target noise reduction area being the driver and passenger seat areas. If both the driver's seat and the sleeper berth gravity sensor modules respond, the driver's seat and sleeper berth noise reduction mode will be activated, with the target noise reduction area being the driver's seat and sleeper berth area.

[0062] In some embodiments, when the adaptive filtering unit runs the filter-X least mean square adaptive algorithm, it is configured to perform: An adaptive filter is used to filter the reference signal to generate an initial control signal; The initial control signal is filtered through the secondary path transfer function model; Based on the filtered signal and the residual noise signal, the coefficients of the adaptive filter are updated using the following formula:

[0063] In the formula, This represents the coefficient vector of the adaptive filter at the next time step; This represents the coefficient vector of the adaptive filter at the current time. This is the preset convergence step size, used to control the convergence speed and stability of the algorithm; This represents the residual noise signal collected at the current moment; This represents the filtered signal obtained by filtering through the secondary path transfer function model at the current moment.

[0064] This invention also provides a commercial vehicle equipped with the active wind noise reduction system for commercial vehicles as described in the above embodiments.

[0065] The vibration sensor is fixed to the sheet metal part on the outside of the cab with bolts. The sensor cable passes through the waterproof seal ring of the cab and enters the interior to connect to the controller or connect to the controller wirelessly. The gravity sensor is embedded between the seat cushion and the frame, and is connected to the vehicle's CAN bus via the seat wiring harness; The error microphone is fixed to the A-pillar interior panel and the sleeper head interior panel with clips, and the cable is hidden in the gap of the interior panel; the controller and power amplifier are integrated in a metal shell and installed under the center console. It is powered by the vehicle's 12V power supply and is also connected to the CAN bus to communicate with the vehicle's ECU (to obtain information such as vehicle speed and gear).

[0066] The system software interacts with the vehicle control system via CAN messages to obtain vehicle speed signals (used to trigger system startup / sleep) and air conditioning fan speed signals (used to compensate for the interference of air conditioning noise on wind noise detection). The driver can turn the system on / off and adjust the noise reduction intensity (3 levels adjustable: weak / medium / strong) via steering wheel buttons or central control screen touch operation.

[0067] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of active wind noise reduction for a commercial vehicle, the method comprising: The method comprises the following steps: S1, collecting wind noise vibration signals through a vibration sensor array arranged on the wind noise sensitive areas of the cab; judging the current wind noise mode and identifying the dominant wind noise source based on the vibration signals; the wind noise sensitive areas include the windshield, rearview mirror, A-pillar, blind area mirror, cab upper fairing and door glass area; S2, synthesizing a predicted noise signal based on the vibration signal of the dominant wind noise source and the pre-stored sound transmission function from the dominant wind noise source position to one or more pre-set noise reduction points in the cab; S3, detecting the occupant distribution state through a gravity sensing module arranged on the seat and / or bunk in the cab, and determining the target noise reduction area and the corresponding noise reduction mode that need to be executed according to the distribution state; the target noise reduction area includes one or more noise reduction points; S4, inputting the predicted noise signal as a reference signal into an active noise reduction controller; The active noise reduction controller runs an adaptive noise reduction algorithm based on the noise reduction mode, the reference signal and the residual noise signal from the error microphone arranged in the target noise reduction area, and generates a control signal for driving the loudspeaker array; S5, emitting a counteracting sound wave in the target noise reduction area to counteract the wind noise through the loudspeaker array according to the control signal.

2. The commercial vehicle wind noise active noise reduction method of claim 1, wherein, In S1, the steps of judging the current wind noise mode and identifying the dominant wind noise source specifically include: real-time comparing the vibration amplitudes of the sensor signals in the vibration sensor array located in different wind noise sensitive areas; if the vibration amplitude of the sensor signal located in the windshield area is greater than the vibration amplitude of the sensor signal located in the door glass area by more than a first pre-set threshold value, it is determined that the current mode is headwind mode, and the windshield area is identified as the dominant wind noise source; if the vibration amplitude of the sensor signal located in the door glass area is greater than the vibration amplitude of the sensor signal located in the windshield area by more than a second pre-set threshold value, it is determined that the current mode is crosswind mode, and the door glass area is identified as the dominant wind noise source; if the differences between the vibration amplitudes of the sensor signals in each wind noise sensitive area are all less than a third pre-set threshold value, it is determined that the current mode is tailwind mode, and multiple wind noise sensitive areas are identified as the dominant wind noise source.

3. The commercial vehicle wind noise active noise reduction method of claim 2, wherein, In S2, the steps of synthesizing a predicted noise signal based on the vibration signal of the dominant wind noise source and the pre-stored sound transmission function specifically include: S21: calling the noise transmission function corresponding to the position of the dominant wind noise source and the one or more pre-set noise reduction points from the pre-stored sound transmission function database; S22: in the frequency domain, convoluting the vibration signal of the dominant wind noise source with the called noise transmission function to calculate the predicted sound pressure signal of the wind noise transmitted to each pre-set noise reduction point; S23: synthesizing a time-domain predicted noise signal containing frequency, amplitude and phase information based on the predicted sound pressure signal.

4. The commercial vehicle wind noise active noise reduction method of claim 3, wherein, In S22, the specific steps of convoluting the vibration signal of the dominant wind noise source with the called noise transmission function in the frequency domain include: S22a, performing fast Fourier transform on the time-domain vibration signal of the dominant wind noise source to obtain its frequency domain representation; S22b, in the frequency domain, the frequency domain representation of the vibration signal is multiplied by the frequency domain representation of the noise transfer function to obtain the frequency domain representation of the predicted sound pressure signal.

5. The commercial vehicle wind noise active noise reduction method of claim 4, wherein, In S23, based on the predicted sound pressure signal, the specific steps of synthesizing a time-domain predicted noise signal containing frequency, amplitude and phase information include: S23a, inverse fast Fourier transform is performed on the frequency domain representation of the predicted sound pressure signal to obtain an initial time-domain predicted noise signal; S23b, the initial time-domain predicted noise signal is amplitude normalized and / or delay compensated to adapt to the input requirements of the active noise reduction controller, and a final time-domain predicted noise signal used as a reference signal is generated.

6. The commercial vehicle wind noise active noise reduction method of claim 5, wherein, In S3, the distribution state of the passengers is detected by the gravity sensing module, and the target noise reduction area and the corresponding noise reduction mode which need to be executed are determined according to the distribution state, which includes: S31, real-time read the signals of the gravity sensing modules on the driver seat, the front passenger seat and the sleeper; S32, compare the signals with the preset weight threshold to determine whether there is a passenger in the corresponding position; S33, based on the judgment result of the passenger in place, map to the predefined noise reduction mode, and determine the target noise reduction area activated by the noise reduction mode: If only the driver seat is determined to have a passenger, it is mapped to the driver noise reduction mode, and the target noise reduction area is determined to be the driver area, and the noise reduction points contained in the driver area are activated; If the driver seat and the front passenger seat are both determined to have passengers, it is mapped to the driver and front passenger noise reduction mode, and the target noise reduction area is determined to be the driver area and the front passenger area, and the noise reduction points contained in the driver area and the front passenger area are activated; If the driver seat and the sleeper are both determined to have passengers, it is mapped to the driver and sleeper noise reduction mode, and the target noise reduction area is determined to be the driver area and the sleeper area, and the noise reduction points contained in the driver area and the sleeper area are activated.

7. The commercial vehicle wind noise active noise reduction method of claim 6, wherein, In S4, the active noise reduction controller performs the following operations: S41, according to the current noise reduction mode, call the secondary path transfer function model corresponding to the activated target noise reduction area; the secondary path transfer function model pre-stores the acoustic path characteristics from the loudspeaker array to the error microphone in the target noise reduction area; S42, using the predicted noise signal as the reference signal, and using the residual noise signal from the error microphone in the target noise reduction area as the error signal, running the filter-X least mean square adaptive algorithm; The execution of the algorithm includes: using a coefficient-adjustable adaptive filter to filter, generating a preliminary control signal; sending the preliminary control signal to the secondary path transfer function model to obtain a filtered signal; calculating an error correlation signal based on the filtered signal and the residual noise signal, and updating the coefficients of the adaptive filter through the LMS algorithm using the error correlation signal, so as to minimize the mean square value of the residual noise signal; S43, output the control signal obtained after real-time processing by the adaptive filter to the loudspeaker array corresponding to the current noise reduction mode.

8. The commercial vehicle wind noise active noise reduction method of claim 7, wherein, The steps of S5 specifically include: S51, distributing the control signal generated by the active noise reduction controller to the power amplifier driving one or more loudspeakers in the target noise reduction area determined according to the current noise reduction mode; S52, amplifying the control signal in electric form by the power amplifier and driving the corresponding loudspeaker to vibrate; S53, the driven loudspeaker radiates sound waves with the same amplitude and opposite phase as the predicted noise signal, which cancels out the original wind noise wave entering the target noise reduction area, achieving the reduction of sound pressure level in the target noise reduction area.

9. A commercial vehicle wind noise active noise reduction system for implementing the method of any one of claims 1-8, characterized by, The system comprises: a wind noise sensitive area arranged on the outer surface of the cab of the commercial vehicle, a vibration sensor array for collecting wind noise vibration signals; a gravity sensing module arranged in the driver seat, the co-driver seat and the bunk in the cab for detecting the distribution state of the passengers, an error microphone array arranged at a preset noise reduction point in the cab for collecting residual noise signals after noise reduction; a loudspeaker array distributed in the cab; an active noise reduction controller in communication connection with the vibration sensor array, the gravity sensing module, the error microphone array and the loudspeaker array, and internally storing a sound transfer function database and a secondary path transfer function database, the active noise reduction controller comprising: a wind noise mode judgment unit for receiving signals of the vibration sensor array and judging the current wind noise mode and identifying the dominant wind noise source based on the vibration amplitude comparison results of each sensor signal; a predicted noise signal synthesis unit for synthesizing a predicted noise signal based on the vibration signal of the dominant wind noise source and the sound transfer function from the dominant wind noise source position to the preset noise reduction point called from the sound transfer function database; a noise reduction mode matching unit for receiving signals of the gravity sensing module and determining the target noise reduction area and the corresponding noise reduction mode requiring active noise reduction according to the distribution state of the passengers; an adaptive filtering unit for taking the predicted noise signal as the reference signal, taking the residual noise signal of the error microphone signal corresponding to the target noise reduction area, calling the secondary path transfer function model corresponding to the current noise reduction mode, running the filter-X least mean square adaptive algorithm, and generating a control signal for driving the loudspeaker array; a distribution unit for distributing the control signal to the loudspeaker corresponding to the target noise reduction area to drive the loudspeaker to emit a cancellation sound wave.

10. A commercial vehicle characterized by The commercial vehicle wind noise active noise reduction system as claimed in claim 9 is provided.

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