A method and system for automatic weight adjustment of active noise reduction in commercial vehicle cabs

Abstract

This application relates to the field of active noise cancellation, specifically to a method and system for automatic adjustment of active noise cancellation weights in a commercial vehicle cab. The method includes: retrieving corresponding preliminary control weights from a pre-stored calibration module based on the current operating conditions and vehicle load status; identifying the positional distribution of the driver and passengers to determine the target area requiring noise reduction; collecting in-cabin noise signals in real time using error microphones placed in the cab; generating refined adjustment weights for each noise frequency band under different target areas; fusing the preliminary control weights and refined adjustment weights to generate final noise reduction weight allocation information for each noise frequency band, inputting this information to the active noise cancellation system; calculating the cancellation sound wave signals that each speaker in the cab needs to emit; and driving the speaker array to emit cancellation sound wave signals through a speaker control system. This improves the smoothness of the active noise cancellation system and ensures superior noise reduction performance under various vehicle operating conditions.

Description

Technical Field

[0001] This application relates to the field of active noise reduction technology, specifically to a method and system for automatic adjustment of active noise reduction weights in a commercial vehicle cab. Background Technology

[0002] In the commercial vehicle sector (especially heavy-duty trucks), noise control in the cab is crucial for improving the driving experience. The primary noise source is the engine, which generates concentrated low-frequency and second-order noise energy that can easily cause significant "ear-pressure" in the enclosed cab, leading to driver fatigue and severely impacting the riding experience. Therefore, active noise cancellation technology has been introduced to specifically suppress this type of low-frequency noise.

[0003] However, existing active noise cancellation systems for commercial vehicles have significant limitations. During the development phase, their noise reduction parameters are typically calibrated and fixed only for a specific typical condition (such as full load). However, in actual operation, a vehicle's load condition dynamically changes between empty, half-load, and full load. Different loads directly affect the engine's load, speed, and torque output, thus altering the noise spectrum characteristics. Fixed noise reduction parameters cannot achieve optimal noise reduction effects under all load conditions, leading to a significant decrease in noise reduction performance under non-calibrated conditions, and potentially even negative effects such as noise amplification. The heavy-duty truck cab is a multi-functional space, serving both driving and resting functions. Existing systems cannot identify whether the driver, passenger, or sleeper berth is occupied, nor can they differentiate the different acoustic environment needs of the occupants. The system can only provide a one-size-fits-all acoustic environment, failing to achieve precise and targeted allocation of noise reduction resources, resulting in a poor user experience and wasted equipment resources.

[0004] Therefore, there is an urgent need in this field for an active noise cancellation system that can simultaneously sense the vehicle's operating status and the needs of the driver and passengers, and dynamically and intelligently adjust the noise reduction weights of each noise frequency band accordingly, so as to achieve the goal of providing the best noise reduction effect and the best acoustic experience under various complex actual working conditions. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method and system for automatically adjusting the active noise reduction weights in commercial vehicle cabs. This solves the problem that active noise reduction systems for heavy-duty trucks cannot adjust the noise reduction weights for each noise frequency band in real time based on vehicle load and the acoustic environment requirements of the driver and passengers in the cab.

[0006] In a first aspect, the present invention provides a method for automatically adjusting the active noise reduction weight in a commercial vehicle cab, comprising the following steps:

[0007] S1. Acquire the reference signal of the whole vehicle in real time, and determine the current operating condition of the vehicle based on the reference signal. The operating condition includes at least idling condition, constant speed condition and acceleration / deceleration condition.

[0008] S2. Obtain the vehicle load status via the vehicle bus;

[0009] S3. Based on the current operating conditions and vehicle load status, retrieve the corresponding preliminary control weights from the pre-stored calibration module; the calibration module stores the preliminary control weights of the active noise reduction system for each noise frequency band under different vehicle load statuses and different operating conditions.

[0010] S4. By using gravity sensing modules installed in multiple locations within the driver's cab, the system identifies the positional distribution of the occupants and determines one or more target areas requiring noise reduction. Simultaneously, error microphones positioned within the driver's cab collect in-vehicle noise signals in real time. Based on the target areas and real-time in-vehicle noise signals, the system generates refined adjustment weights for each noise frequency band under different target areas.

[0011] S5. The preliminary control weights and the refined adjustment weights are fused together to generate the final noise reduction weight allocation information for each noise frequency band.

[0012] S6. Input the final noise reduction weight allocation information into the active noise reduction system. The active noise reduction system calculates the cancellation sound wave signal that each speaker in the driver's cab needs to emit, and drives the speaker array to emit the cancellation sound wave signal through the speaker control system.

[0013] It can automatically match the optimal initial noise reduction strategy based on the vehicle's real-time operating conditions and load, overcoming the shortcomings of existing technologies that suffer from poor noise reduction performance under different conditions such as no-load and full-load due to fixed calibration, thus ensuring consistent noise reduction performance across all operating conditions. It can identify the location of occupants and accordingly adjust the weight of noise in different areas and frequency bands, providing the most suitable acoustic environment for drivers, resting passengers, etc., greatly improving the user experience. By organically combining macro-level strategies based on vehicle status with micro-level adjustments based on occupant needs, limited noise reduction resources (speaker power, computing power) are prioritized for allocation to the areas and frequency bands most in need of noise reduction, achieving an optimal balance between noise reduction effect and system efficiency.

[0014] As a preferred embodiment of the technical solution of the present invention, in S1, the reference signal includes vehicle speed, engine speed, engine torque, gear position, and accelerator pedal opening; the step of determining the current operating condition of the vehicle based on the reference signal includes:

[0015] When the engine speed is detected to be stable within the idle speed range, the vehicle speed is 0 km / h, the gear is in neutral, and the accelerator pedal opening is 0%, the vehicle is determined to be in idle condition.

[0016] When the engine speed is detected to be stable within the first preset range and the vehicle speed fluctuation is within the preset threshold, the vehicle is determined to be in a constant speed condition.

[0017] When it is detected that within a preset first time window, the absolute value of the rate of change of engine speed continuously exceeds a first preset threshold, and the vehicle speed fluctuation exceeds the preset threshold, and the engine torque and accelerator pedal opening increase or decrease in the same direction, the vehicle is determined to be in an acceleration / deceleration condition.

[0018] By introducing specific reference signals and quantified judgment logic, the operating condition judgment is accurate and reliable, avoiding misjudgments and laying a solid foundation for the subsequent accurate query of weights, thus ensuring the accuracy and stability of the system response.

[0019] As a preferred embodiment of the technical solution of the present invention, in step S3, the calibration module is pre-established through the following calibration steps:

[0020] S31. For vehicles equipped with active noise cancellation, noise collection and testing are conducted in the cab under different load conditions and based on various driving conditions; driving conditions include idling, constant speed, and acceleration / deceleration.

[0021] S32. Based on the test results, analyze the contribution of each noise frequency band to the overall noise of the cab under various driving conditions.

[0022] S33. Based on the contribution analysis results, for different combinations of vehicle load conditions and operating conditions, the control weights of the active noise reduction system for each noise frequency band are initially determined and stored to form a calibration module.

[0023] Through a systematic calibration process, it is ensured that the stored preliminary control weights can accurately reflect the noise characteristics under different conditions, thus guaranteeing the effectiveness of the preliminary control strategy from the source.

[0024] As a preferred embodiment of the technical solution of the present invention, the step of initially determining the control weights of the active noise reduction system for each noise frequency band in S33 includes:

[0025] S331. Based on the contribution analysis results of S32, control weights are assigned to each noise frequency band according to the principle that the greater the contribution of the noise frequency band, the higher the control weight is assigned.

[0026] S332. For each combination of vehicle load state and operating condition, generate a corresponding noise reduction weight matrix. The noise reduction weight matrix defines the initial control weight of the active noise reduction system for each target noise frequency band under the corresponding combination state.

[0027] S333. Store the set of denoising weight matrices for all combined states as the calibration module.

[0028] The core principle of weight allocation is clearly defined: greater contribution corresponds to greater weight. This allows noise reduction resources to be precisely focused on the most significant and annoying noise sources, avoiding energy waste. Furthermore, storing the weights in the form of a noise reduction weight matrix provides a clear structure, facilitating rapid system retrieval and matching, thus improving real-time performance.

[0029] As a preferred embodiment of the technical solution of the present invention, in step S4, the step of identifying the positional distribution of the driver and passengers by using gravity sensing modules installed at multiple locations in the driver's cab, and determining one or more target areas requiring noise reduction, includes:

[0030] S41a, Read the output signals of the gravity sensor modules installed in the driver's seat, passenger seat and sleeper berth of the cab respectively;

[0031] S41b: Compare the output signal of the gravity sensor module at each location with a preset weight threshold. If the signal value exceeds the weight threshold, it is determined that there is a passenger at that location.

[0032] S41c: Based on the judgment result of S41b, all locations with occupants and adjacent areas acoustically associated with the locations are identified as target areas for noise reduction in this round of noise reduction cycle.

[0033] Personnel identification via gravity sensing is simple, reliable, and privacy-preserving. In particular, including acoustically related neighboring areas in the target area demonstrates a deep understanding of the acoustic spatial coupling within the driver's cab. This enables area-level rather than point-level noise reduction for the target seats, eliminating acoustic blind spots and enhancing the overall sense of quietness.

[0034] As a preferred embodiment of the technical solution of the present invention, in S4, the specific steps for generating refined adjustment weights for each noise frequency band under different target areas based on the target area and the real-time in-vehicle noise signal include:

[0035] S42a. Based on the predefined acoustic requirement mapping relationship, the identified location distribution state is mapped into weight adjustment coefficients for different target areas and target noise reduction frequency bands;

[0036] S42b: Perform frequency domain analysis on the real-time in-vehicle noise signal to obtain the actual sound pressure level of each noise frequency band.

[0037] S42c. For each target region, multiply the weight adjustment coefficient obtained in S42a by the actual sound pressure level obtained in S42b to obtain the refined adjustment weight of each noise frequency band in the target region.

[0038] By correlating the location information of personnel with the physical signal of real-time noise through a quantification tool called weight adjustment coefficients, human needs are transformed into calculable parameters. The algorithm, combining these parameters via multiplication, is concise, efficient, and easy to implement in a controller, while ensuring that the generation of refined weights both conforms to human preferences and responds to actual environmental changes.

[0039] As a preferred embodiment of the technical solution of the present invention, the acoustic requirement mapping relationship includes:

[0040] When it is detected that there is only an occupant in the driver's seat, the weight adjustment coefficient mapped to the engine order noise frequency band of the target area of ​​the driver's seat is greater than 1, while the adjustment coefficient for other frequency bands is equal to or less than 1.

[0041] When a passenger is detected at a sleeper berth, the weighting adjustment coefficient for the broadband noise mapped to the target area of ​​the sleeper berth is greater than 1, while the adjustment coefficient for other frequency bands is equal to or less than 1.

[0042] The system concretizes and quantifies two of the most typical commercial vehicle interior scenarios (driver on duty only, sleeper berth rest) and their optimal acoustic strategies. For example, prioritizing first-order noise for the driver ensures the clarity of auditory information required for driving; prioritizing broadband noise for the sleeper berth creates a completely quiet environment ideal for rest. This directly reflects the system's intelligence and human-centered design.

[0043] As a preferred embodiment of the technical solution of the present invention, step S5 includes:

[0044] S51. Ensure that the initial control weights and the fine-tuning weights are consistent with the noise frequency band definitions; if the frequency band definitions are inconsistent, the weights need to be calibrated for frequency band matching.

[0045] S52. For each noise frequency band, the corresponding preliminary control weight and fine adjustment weight are calculated using a predefined fusion algorithm to obtain the final noise reduction weight for the corresponding noise frequency band.

[0046] S53. Normalize the final noise reduction weights of all noise frequency bands obtained after fusion calculation so that the sum of the final noise reduction weights after processing meets the requirements of the active noise reduction system, and output the final noise reduction weight allocation information.

[0047] The standardized process of alignment, fusion, and normalization ensures that weights from different sources and with different dimensions can be safely and effectively merged. Normalization prevents system overload or distortion that may result from weight superposition, ensuring that the generated control signals are smooth and stable, and improving the robustness of the system.

[0048] As a preferred embodiment of the technical solution of the present invention, in step S6, the specific steps for calculating the canceling sound wave signals that each speaker in the driver's cab needs to emit include:

[0049] S61, Invoke the pre-stored sound transfer function from each speaker to each target area;

[0050] S62. Based on the final noise reduction weight allocation information, calculate and synthesize the cancellation sound wave signals that each speaker needs to emit for different target areas.

[0051] By calling the sound transfer function and independently calculating and synthesizing signals for different target areas, zoned noise reduction is achieved at the algorithm level. This enables the system to create multiple independent quiet zones within the vehicle using a speaker array. It can achieve noise reduction in the driver's area without interfering with the acoustic environment of the sleeper area, or create a quiet zone in the sleeper area without affecting the driver's hearing. This precise sound field control is an advanced function that traditional global noise reduction systems cannot achieve.

[0052] Secondly, the present invention also provides an active noise reduction weight automatic adjustment system for a commercial vehicle cab, used to implement the method described in the first aspect, comprising:

[0053] The vehicle status judgment module is used to acquire the reference signals of the whole vehicle in real time and judge the current operating condition of the vehicle based on the reference signals.

[0054] The load status acquisition module is used to acquire the vehicle load status through the vehicle bus.

[0055] The calibration module pre-stores the initial control weights of the active noise cancellation system for each noise frequency band under different vehicle load conditions and different operating conditions.

[0056] The preliminary weight query module is connected to the vehicle status judgment module, the load status acquisition module and the calibration module, and is used to retrieve the corresponding preliminary control weights from the calibration module according to the current operating conditions and vehicle load status.

[0057] The fine-grained weight calculation module has its input end connected to a gravity sensing module and an error microphone located at multiple positions in the driver's cab. It is used to generate fine-grained adjustment weights for different noise frequency bands in different target areas based on the target area determined by the distribution of driver and passenger positions identified by the gravity sensing module and the in-vehicle noise signal collected in real time by the error microphone.

[0058] The weight fusion module, connected to the preliminary weight query module and the refined weight calculation module, is used to fuse the preliminary control weights and the refined adjustment weights to generate final noise reduction weight allocation information for each noise frequency band.

[0059] The noise reduction execution module is connected to the weight fusion module and is used to input the final noise reduction weight allocation information to the active noise reduction system. The active noise reduction system calculates the cancellation sound wave signal that each speaker in the driver's cab needs to emit, and drives the speaker array to emit the cancellation sound wave signal through the speaker control system.

[0060] As can be seen from the above technical solutions, this application has the following advantages: by identifying the vehicle status, the noise situation in the driver's cabin, and the needs of the driver and passengers for the acoustic environment, the noise frequency and sound energy output by each speaker can be precisely controlled, so as to achieve the best effect while avoiding unnecessary power output, achieving energy saving, and extending the life of the active noise cancellation equipment.

[0061] By using the weight allocation signal output by the active noise reduction weight controller, the frequency and energy of each sound that each speaker in the cab needs to emit are calculated in the active noise reduction system, so as to accurately control the noise in the area that needs to be reduced.

[0062] The system monitors vehicle reference signals (vehicle speed, engine speed, engine torque, gear position, accelerator pedal opening, etc.) and simultaneously collects noise signals in real time through error microphones located in the cab. It also adjusts the noise reduction weights of each frequency band in real time to ensure that the active noise cancellation system has the best noise reduction effect under all operating conditions. Attached Figure Description

[0063] 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.

[0064] Figure 1 This is a flowchart illustrating the method provided in an embodiment of the present invention.

[0065] Figure 2 A block diagram of a system provided in an embodiment of the present invention. Detailed Implementation

[0066] 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.

[0067] 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.

[0068] like Figure 1 As shown in the figure, this invention provides a method for automatic adjustment of active noise reduction weights in a commercial vehicle cab, comprising the following steps:

[0069] S1. Acquire reference signals of the entire vehicle in real time, and determine the current operating condition of the vehicle based on the reference signals. The operating conditions include at least idling, constant speed, and acceleration / deceleration. The reference signals include vehicle speed, engine speed, engine torque, gear position, and accelerator pedal opening. The steps for determining the current operating condition of the vehicle based on the reference signals include:

[0070] When the engine speed is detected to be stable within the idle speed range, the vehicle speed is 0 km / h, the gear is in neutral, and the accelerator pedal opening is 0%, the vehicle is determined to be in idle condition.

[0071] When the engine speed is detected to be stable within the first preset range and the vehicle speed fluctuation is within the preset threshold, the vehicle is determined to be in a constant speed condition.

[0072] When it is detected that within a preset first time window, the absolute value of the rate of change of engine speed continuously exceeds a first preset threshold, and the vehicle speed fluctuation exceeds the preset threshold, and the engine torque and accelerator pedal opening increase or decrease in the same direction, the vehicle is determined to be in an acceleration / deceleration condition.

[0073] S2. Obtain the vehicle load status via the vehicle bus;

[0074] S3. Based on the current operating conditions and vehicle load status, retrieve the corresponding preliminary control weights from the pre-stored calibration module; the calibration module stores the preliminary control weights of the active noise cancellation system for each noise frequency band under different vehicle load statuses and different operating conditions; it should be noted that the calibration module is pre-established through the following calibration steps:

[0075] S31. For vehicles equipped with active noise cancellation, noise collection and testing are conducted in the cab under different load conditions and based on various driving conditions; driving conditions include idling, constant speed, and acceleration / deceleration.

[0076] S32. Based on the test results, analyze the contribution of each noise frequency band to the overall noise of the cab under various driving conditions.

[0077] Analyzing the contribution of each noise frequency band to the overall noise level of the cab refers to identifying one or more key noise frequency bands that play a dominant role in the overall noise level or subjective annoyance of the cab under specific vehicle load conditions and operating conditions, based on sound pressure level analysis or psychoacoustic parameter analysis.

[0078] For example, this can be achieved by calculating the total sound pressure level contribution of each one-third octave band, or by calculating the contribution ratio of a specific frequency band to the total loudness in the Zwicker loudness analysis method. The aim is to identify one or more key noise frequency bands that have the greatest impact on octave passengers under specific operating conditions and vehicle load conditions. One-third octave band sound pressure levels are calculated by decomposing the noise signal into different frequency bandwidths and comparing which band has the highest sound pressure level; this band is generally considered to have the largest contribution.

[0079] Zwicker loudness analysis takes into account the nonlinear characteristics of the human ear's sensitivity to different frequencies (equal loudness curves), and the calculated loudness is more representative of the degree of noise impact than simple sound pressure level. Analyzing the contribution of specific frequency bands to the total loudness allows for a more precise identification of frequency bands that need to be prioritized.

[0080] S33. Based on the contribution analysis results, for different combinations of vehicle load conditions and operating conditions, the control weights of the active noise reduction system for each noise frequency band are initially determined and stored to form a calibration module.

[0081] During the development phase of the active noise cancellation system for heavy-duty trucks, signals such as engine speed and torque are collected under various load conditions and common driving conditions (e.g., idling, constant speed, acceleration, and climbing). Combined with the noise levels inside the cab, the acoustic environment required by the driver and passengers is determined, and the initial control weights for each frequency band of the active noise cancellation system are assigned. The relevant data is recorded in the calibration module. This module enables the active noise cancellation system to respond quickly to the acoustic environment requirements of different vehicle conditions, improving the system's smoothness and ensuring optimal noise reduction performance under various vehicle operating conditions.

[0082] It should be further noted that the steps for initially determining the control weights of the active noise cancellation system for each noise frequency band include:

[0083] S331. Based on the contribution analysis results of S32, control weights are assigned to each noise frequency band according to the principle that the greater the contribution of the noise frequency band, the higher the control weight is assigned.

[0084] S332. For each combination of vehicle load state and operating condition, generate a corresponding noise reduction weight matrix, as shown in Table 1. The noise reduction weight matrix defines the initial control weight of the active noise reduction system for each target noise frequency band under the corresponding combination state.

[0085] Table 1: Noise Reduction Weight Matrix

[0086]

[0087] S333. Store the set of denoising weight matrices for all combined states as the calibration module.

[0088] S4. By using gravity sensing modules installed in multiple locations within the driver's cab, the system identifies the positional distribution of the occupants and determines one or more target areas requiring noise reduction. Simultaneously, error microphones positioned within the driver's cab collect in-vehicle noise signals in real time. Based on the target areas and real-time in-vehicle noise signals, the system generates refined adjustment weights for each noise frequency band under different target areas.

[0089] Gravity sensor modules are added to the driver's seat, passenger seat, and sleeper berth to identify the acoustic environment requirements of drivers and passengers in the cab. Based on research on drivers and passengers of heavy trucks, the active noise reduction weight adjustment system adjusts the noise reduction weight of each noise frequency band in the noise reduction area according to the acoustic environment requirements and driving habits of drivers and passengers.

[0090] In this step, the process of identifying the positional distribution of the occupants and determining one or more target areas requiring noise reduction by using gravity sensing modules installed at multiple locations within the driver's cab includes:

[0091] S41a, Read the output signals of the gravity sensor modules installed in the driver's seat, passenger seat and sleeper berth of the cab respectively;

[0092] S41b: Compare the output signal of the gravity sensor module at each location with a preset weight threshold. If the signal value exceeds the weight threshold, it is determined that there is a passenger at that location.

[0093] S41c: Based on the judgment result of S41b, all locations with occupants and adjacent areas acoustically associated with the locations are identified as target areas for noise reduction in this round of noise reduction cycle.

[0094] Furthermore, the specific steps for generating refined adjustment weights for each noise frequency band under different target areas, based on the target area and real-time in-vehicle noise signals, include:

[0095] S42a. Based on a predefined acoustic requirement mapping relationship, the identified location distribution state is mapped to weight adjustment coefficients for different target areas and target noise reduction frequency bands. It should be noted that during the system development phase, an acoustic requirement mapping table is defined based on the acoustic design of the commercial vehicle cab and the comfort requirements of the driver and passengers. This table details the acoustic requirement priority of each target area for different noise frequency bands under different driver and passenger location distribution states.

[0096] For example, if there are occupants in the driver's seat but not in other positions, the noise reduction requirements for engine order noise (such as low-frequency noise) in the driver's area may be higher. Therefore, the weight adjustment coefficient for the low-frequency noise band in the driver's area can be defined to be greater than 1, while the weight adjustment coefficient for other frequency bands can be equal to or less than 1.

[0097] Similarly, if there are passengers in the sleeper berth, there may be a higher demand for noise reduction of broadband noise (such as mid-to-high frequency noise). Therefore, the weight adjustment coefficient for broadband noise frequency bands in the sleeper area can be defined to be greater than 1, while the weight adjustment coefficient for other frequency bands can be equal to or less than 1.

[0098] Based on the occupant location distribution identified by the gravity sensor module in step S41, the acoustic demand mapping table is queried. For each target area, the corresponding weight adjustment coefficients are obtained from the acoustic demand mapping table based on whether there are occupants in that area and their locations. These weight adjustment coefficients will be used for subsequent fine-tuning weight calculations.

[0099] S42b: Perform frequency domain analysis on the real-time in-vehicle noise signal to obtain the actual sound pressure level of each noise frequency band.

[0100] Error microphones positioned inside the driver's cab are used to collect noise signals in real time. These microphones are distributed across different target areas to ensure accurate capture of noise levels in each area.

[0101] The acquired noise signal is transmitted to the signal processing module for further analysis. In the signal processing module, a Fourier transform is performed on the acquired noise signal, converting it from the time domain to the frequency domain. The Fourier transform yields the amplitude and phase information of the noise signal at different frequencies. The frequency domain signal is analyzed to determine the actual sound pressure level (SPL) for each noise frequency band. SPL is typically expressed in decibels (dB) and reflects the intensity of noise at different frequencies. The actual SPL for each noise frequency band is recorded for subsequent fine-tuning weight calculations.

[0102] S42c. For each target region, multiply the weight adjustment coefficient obtained in S42a by the actual sound pressure level obtained in S42b to obtain the refined adjustment weight of each noise frequency band in the target region.

[0103] Specifically, for the target region j and the noise frequency band k, the weights are finely adjusted. Represented as:

[0104] in, It is the weighting adjustment factor. This is the actual sound pressure level;

[0105] The purpose of this product operation is to combine the acoustic needs of drivers and passengers (reflected by the weighting adjustment coefficient) with the current actual noise situation (reflected by the actual sound pressure level), thereby obtaining a refined adjustment weight that comprehensively considers the needs of drivers and passengers and the actual noise level.

[0106] To ensure the comparability and consistency of the fine-tuning weights across different target regions and noise frequency bands, the calculated fine-tuning weights are normalized. Normalization adjusts the weight values ​​to a uniform range, such as between 0 and 1.

[0107] The normalized, refined adjustment weights will be used as the final adjustment weight values ​​for subsequent noise reduction weight allocation and acoustic signal cancellation calculations.

[0108] S5. The preliminary control weights and the refined adjustment weights are fused to generate the final noise reduction weight allocation information for each noise frequency band; this step specifically includes:

[0109] S51. Ensure that the initial control weights are consistent with the noise frequency bands targeted by the refined adjustment weights;

[0110] First, obtain the initial control weights from the calibration module in S3. These weights are pre-set based on the vehicle's load condition and operating conditions, and are applied to different noise frequency bands. .

[0111] At the same time, obtain refined adjustment weights These weights are calculated based on real-time in-vehicle noise signals and the positional distribution of passengers, and are also tailored to different noise frequency bands. .

[0112] Check whether the noise frequency bands corresponding to the two sets of weights are defined in the same way. Noise frequency bands are usually defined by frequency ranges. For example, the low frequency band may be 20 Hz-100 Hz, the mid frequency band may be 100 Hz-1kHz, and the high frequency band may be 1kHz-20 kHz, etc.

[0113] If inconsistencies in frequency band definitions are found, one set of weights needs to be adjusted to match the frequency band definition of the other set. For example, if the frequency band definition for the initial control weights is 20 Hz-100 Hz, while the frequency band definition for the fine-tuning weights is 30 Hz-120 Hz, then either the initial control weights or the fine-tuning weights need to be redefined to ensure that both are within the same frequency band range for subsequent fusion calculations.

[0114] S52. For each noise frequency band, the corresponding preliminary control weight and fine adjustment weight are calculated using a predefined fusion algorithm to obtain the final noise reduction weight for the corresponding noise frequency band.

[0115] Based on system design requirements, a suitable fusion algorithm is selected. Common fusion algorithms include weighted average method, linear combination method, and nonlinear combination method. In this embodiment of the invention, the weighted average method is used and can be implemented using the following formula:

[0116]

[0117] Among them, among them, It is the final noise reduction weight. This is the initial control of weights. It is a fine-tuning of weights. It is a weighting coefficient between 0 and 1, used to balance the contributions of the initial control weight and the fine-tuning weight in the fusion process.

[0118] For each noise frequency band The selected fusion algorithm is applied to initially control the weights. and fine-tuning weights Perform fusion calculations to obtain the final noise reduction weights. .

[0119] For example, choosing the weighted average method, and =0.7, then for the target area j and noise band k The final noise reduction weights are calculated as follows:

[0120]

[0121] Repeat the above calculation process to obtain the final noise reduction weights for all noise frequency bands.

[0122] S53. Normalize the final noise reduction weights of all noise frequency bands obtained after fusion calculation so that the sum of the final noise reduction weights after processing meets the requirements of the active noise reduction system, and output the final noise reduction weight allocation information.

[0123] Calculate the final sum of noise reduction weights for all noise frequency bands. :

[0124]

[0125] in, k Indicates the index of all noise frequency bands.

[0126] To ensure that the final sum of noise reduction weights meets the requirements of an active noise cancellation system, the weights typically need to be normalized to a specific range, such as between 0 and 1. Normalization can be achieved using the following formula:

[0127]

[0128] in, These are the final noise reduction weights after normalization. Through normalization, the sum of the final noise reduction weights after normalization for all noise frequency bands is ensured to be 1.

[0129] The normalized final noise reduction weights The output is sent to the active noise cancellation system as the final noise reduction weight allocation information. These weights will be used in subsequent calculations of the canceled sound wave signals to ensure that the active noise cancellation system can accurately control the canceled sound wave signals emitted by each speaker according to the current vehicle status and the needs of the passengers, thereby achieving the best noise reduction effect.

[0130] S6. Input the final noise reduction weight allocation information into the active noise reduction system. The active noise reduction system calculates the cancellation sound wave signal that each speaker in the driver's cab needs to emit, and drives the speaker array to emit the cancellation sound wave signal through the speaker control system.

[0131] In this embodiment of the invention, the specific steps for calculating the canceling sound wave signals that each speaker in the driver's cab needs to emit include:

[0132] S61, Invoke the pre-stored sound transfer function from each speaker to each target area;

[0133] During the system development phase, a detailed model of the acoustic environment inside the driver's cab is created. Using professional acoustic measurement equipment, such as sound pressure level meters and sound field analyzers, measurement sensors are placed at different locations within the driver's cab (e.g., the driver's seat, passenger seat, sleeper berth, and other target areas).

[0134] A standard sound wave signal with a known frequency and amplitude is emitted to each speaker in the driver's cab. Simultaneously, the frequency response characteristics of the sound wave signals received by the sensors in each target area are recorded, including amplitude and phase information. These frequency response characteristics constitute the sound transfer function from each speaker to each target area.

[0135] These sound transfer functions are stored in the system's database in the form of tables or matrices, with each sound transfer function uniquely identified and associated with its corresponding speaker and target area. For example, a sound transfer function can be represented as... ,in Indicates the speaker number. Indicates the target area number. Indicates frequency.

[0136] During the operation of the active noise cancellation system, when it is necessary to calculate the cancellation of sound wave signals, the corresponding sound transfer function is called from the database according to the current target area and speaker configuration.

[0137] The system identifies the target area requiring noise reduction and simultaneously acquires the speaker number and status information of each speaker in the loudspeaker control system. For each combination of target area and speaker, the corresponding sound transfer function is retrieved from the database. These functions are then loaded into the signal processing module of the active noise cancellation system to provide basic data for subsequent calculations of the canceled acoustic signal.

[0138] S62. Based on the final noise reduction weight allocation information, for different target areas, the cancellation sound wave signals that each speaker needs to emit are independently calculated and synthesized, so that the noise reduction effect of each target area is independently optimized.

[0139] First, obtain the final noise reduction weight allocation information output by S5. This information includes the final noise reduction weights for each target region and each noise frequency band. ,in Indicates the target area number. Indicates the noise frequency band number. Indicates frequency.

[0140] For each target area Based on the frequency domain analysis results of the current in-vehicle noise signal (obtained from S42b), the noise frequency bands that need to be canceled are determined. and its corresponding sound pressure level .

[0141] According to the sound transfer function and final noise reduction weights Calculate each speaker Target area and noise band The acoustic signal that needs to be emitted to cancel out The calculation formula can be expressed as:

[0142]

[0143] in, It is the inverse function of the sound transfer function, used to calculate the back-propagation characteristics of sound waves from the target area to the loudspeaker, to ensure that the canceling sound wave signal can accurately produce a canceling effect in the target area.

[0144] For each speaker It will target different regions and noise band The calculated canceled acoustic signal Synthesis is then performed. The synthesis process can employ a weighted summation method, considering the importance of different target regions and noise frequency bands, to obtain the final composite canceled sound wave signal that the loudspeaker needs to emit. The synthesis formula can be expressed as:

[0145]

[0146] in, It is for the target area and noise band The weighting coefficients are used to balance the contributions of different target regions and noise frequency bands in the noise reduction process.

[0147] The calculated combined canceled acoustic signal The signals are converted into time-domain signals (if the original calculations were performed in the frequency domain) and then sent to the corresponding speakers via the speaker control system. The speaker control system drives the speaker array to emit corresponding canceling sound wave signals based on the amplitude and phase requirements of the signals, thereby achieving precise noise reduction in each target area within the driver's cab.

[0148] S63. The loudspeaker control system dynamically adjusts the output power of each loudspeaker according to the noise reduction demand intensity of each frequency band indicated by the final noise reduction weight allocation information. When the average value of the final noise reduction weight of all frequency bands is lower than the first power threshold, it is determined that the overall noise reduction demand is low, and some or all loudspeakers are controlled to operate in low power mode.

[0149] Final noise reduction weight allocation information Calculate the average of the final noise reduction weights for all noise frequency bands. :

[0150] in, N This is the total number of noise frequency bands. It is an index of the noise frequency band.

[0151] The calculated average value With the preset first power threshold Comparison. First power threshold. It is a value pre-set according to system design and actual needs, used to determine the level of overall noise reduction requirements.

[0152] if If the overall noise reduction requirement is low, then it can be determined that the overall noise reduction requirement is low.

[0153] When overall noise reduction requirements are low, the speaker control system will switch some or all speakers to low-power mode. Specific implementation methods for low-power mode may include:

[0154] Reduce speaker output power: Reduce speaker output power by adjusting the amplitude of the speaker drive signal. For example, the speaker output power can be reduced to a certain percentage of normal power (such as 50% or lower).

[0155] Turn off some speakers: If the system design allows, you can choose to turn off some speakers to further reduce the system's energy consumption. For example, you can turn off speakers that contribute less to the current noise reduction effect.

[0156] if If the overall noise reduction requirement is high, the speaker control system will keep the speaker running in normal power mode to ensure sufficient noise reduction effect.

[0157] The speaker control system needs to monitor changes in the in-vehicle noise environment and the needs of the occupants in real time. If the in-vehicle noise conditions change during low-power operation (such as a sudden increase in noise level), the system should be able to detect this change promptly and adjust the speaker output power according to the new final noise reduction weighting information.

[0158] Similarly, if the in-vehicle noise level decreases during normal power mode operation, the system should be able to dynamically adjust the speaker output power based on the new weighting information to achieve the best balance between energy saving and noise reduction.

[0159] like Figure 2 As shown, this embodiment of the invention also provides an active noise reduction weight automatic adjustment system for commercial vehicle cabs, used to implement the methods described in the above embodiments, including:

[0160] The vehicle status judgment module is used to acquire the reference signals of the whole vehicle in real time and judge the current operating condition of the vehicle based on the reference signals.

[0161] The load status acquisition module is used to acquire the vehicle load status through the vehicle bus.

[0162] The calibration module pre-stores the initial control weights of the active noise cancellation system for each noise frequency band under different vehicle load conditions and different operating conditions.

[0163] The preliminary weight query module is connected to the vehicle status judgment module, the load status acquisition module and the calibration module, and is used to retrieve the corresponding preliminary control weights from the calibration module according to the current operating conditions and vehicle load status.

[0164] The fine-grained weight calculation module has its input end connected to a gravity sensing module and an error microphone located at multiple positions in the driver's cab. It is used to generate fine-grained adjustment weights for different noise frequency bands in different target areas based on the target area determined by the distribution of driver and passenger positions identified by the gravity sensing module and the in-vehicle noise signal collected in real time by the error microphone.

[0165] The weight fusion module, connected to the preliminary weight query module and the refined weight calculation module, is used to fuse the preliminary control weights and the refined adjustment weights to generate final noise reduction weight allocation information for each noise frequency band.

[0166] The noise reduction execution module is connected to the weight fusion module and is used to input the final noise reduction weight allocation information to the active noise reduction system. The active noise reduction system calculates the cancellation sound wave signal that each speaker in the driver's cab needs to emit, and drives the speaker array to emit the cancellation sound wave signal through the speaker control system.

[0167] In some embodiments, the vehicle status determination module is configured as follows:

[0168] When the engine speed is detected to be stable within the idle speed range, the vehicle speed is 0 km / h, the gear is in neutral, and the accelerator pedal opening is 0%, the vehicle is determined to be in idle condition.

[0169] When the engine speed is detected to be stable within the first preset range and the vehicle speed fluctuation is within the preset threshold, the vehicle is determined to be in a constant speed condition.

[0170] When it is detected that within a preset first time window, the absolute value of the rate of change of engine speed continuously exceeds a first preset threshold, and the vehicle speed fluctuation exceeds the preset threshold, and the engine torque and accelerator pedal opening increase or decrease in the same direction, the vehicle is determined to be in an acceleration / deceleration condition.

[0171] In some embodiments, the data in the calibration module is pre-established in the following manner:

[0172] For vehicles equipped with active noise cancellation, noise collection and testing were conducted in the cab under different load conditions and various driving conditions.

[0173] Based on the test results, the contribution of each noise frequency band to the overall noise of the cab under various driving conditions was analyzed.

[0174] Based on the contribution analysis results, for different combinations of vehicle load conditions and operating conditions, the control weights of the active noise reduction system for each noise frequency band are initially determined and stored to form a calibration module.

[0175] In some embodiments, the refined weight calculation module includes:

[0176] The demand mapping unit is used to map the identified location distribution state into weight adjustment coefficients for different target areas and target noise reduction frequency bands according to a predefined acoustic demand mapping relationship.

[0177] The noise analysis unit is used to perform frequency domain analysis on real-time in-vehicle noise signals to obtain the actual sound pressure level of each noise frequency band.

[0178] The weight calculation unit is used to multiply the weight adjustment coefficient by the actual sound pressure level for each target area to obtain the fine adjustment weight of each noise frequency band in the target area.

[0179] In some embodiments, the predefined acoustic requirement mapping relationship includes:

[0180] When it is detected that there is only an occupant in the driver's seat, the weight adjustment coefficient mapped to the engine order noise frequency band of the target area of ​​the driver's seat is greater than 1, while the adjustment coefficient for other frequency bands is equal to or less than 1.

[0181] When a passenger is detected at a sleeper berth, the weighting adjustment coefficient for the broadband noise mapped to the target area of ​​the sleeper berth is greater than 1, while the adjustment coefficient for other frequency bands is equal to or less than 1.

[0182] In some embodiments, the noise reduction execution module is configured to: call a pre-stored sound transfer function from each speaker to each target region; and, based on the final noise reduction weight allocation information, independently calculate and synthesize the cancellation sound wave signals that each speaker needs to emit for different target regions.

[0183] 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 for automatically adjusting the active noise reduction weight in a commercial vehicle cab, characterized in that, Includes the following steps: S1. Acquire the reference signal of the whole vehicle in real time, and determine the current operating condition of the vehicle based on the reference signal. The operating condition includes at least idling condition, constant speed condition and acceleration / deceleration condition. S2. Obtain the vehicle load status via the vehicle bus; S3. Based on the current operating conditions and vehicle load status, retrieve the corresponding preliminary control weights from the pre-stored calibration module; the calibration module stores the preliminary control weights of the active noise reduction system for each noise frequency band under different vehicle load statuses and different operating conditions. The calibration module is pre-established through the following calibration steps: S31, For vehicle models adapted to active noise cancellation, noise is collected and tested in the cab under different load conditions and various driving conditions; driving conditions include idling, constant speed, and acceleration / deceleration; S32, Based on the test results, the contribution of each noise frequency band to the overall noise in the cab under each driving condition is analyzed; S33, Based on the contribution analysis results, the control weight of the active noise cancellation system for each noise frequency band is initially determined for different combinations of vehicle load conditions and operating conditions, and stored to form the calibration module; S4. By using gravity sensing modules installed in multiple locations in the driver's cab, the system identifies the positional distribution of the occupants and determines one or more target areas that require noise reduction. Simultaneously, error microphones installed in the driver's cab collect in-vehicle noise signals in real time. Based on the target area and real-time in-vehicle noise signal, fine-grained adjustment weights for each noise frequency band under different target areas are generated; specifically, this includes: S42a, mapping the identified location distribution state into weight adjustment coefficients for different target areas and target noise reduction frequency bands according to a predefined acoustic requirement mapping relationship; S42b, performing frequency domain analysis on the real-time in-vehicle noise signal to obtain the actual sound pressure level of each noise frequency band; S42c, for each target area, multiplying the weight adjustment coefficients obtained in S42a with the actual sound pressure level obtained in S42b to obtain the fine-grained adjustment weights for each noise frequency band under that target area; S5. The preliminary control weights and the refined adjustment weights are fused to generate final noise reduction weight allocation information for each noise frequency band; specifically, this includes: S51. Ensuring that the noise frequency bands targeted by the preliminary control weights and the refined adjustment weights are consistent; S52. For each noise frequency band, the corresponding preliminary control weights and refined adjustment weights are calculated using a predefined fusion algorithm to obtain the final noise reduction weight for the corresponding noise frequency band; S53. The final noise reduction weights of all noise frequency bands obtained after fusion calculation are normalized so that the sum of the processed final noise reduction weights meets the requirements of the active noise cancellation system, and the final noise reduction weight allocation information is output. S6. Input the final noise reduction weight allocation information into the active noise reduction system. The active noise reduction system calculates the cancellation sound wave signal that each speaker in the driver's cab needs to emit, and drives the speaker array to emit the cancellation sound wave signal through the speaker control system.

2. The method for automatic adjustment of active noise reduction weights in a commercial vehicle cab according to claim 1, characterized in that, In S1, the reference signals include vehicle speed, engine speed, engine torque, gear position, and accelerator pedal opening. The steps for determining the current operating condition of the vehicle based on the reference signal include: When the engine speed is detected to be stable within the idle speed range, the vehicle speed is 0 km / h, the gear is in neutral, and the accelerator pedal opening is 0%, the vehicle is determined to be in idle condition. When the engine speed is detected to be stable within the first preset range and the vehicle speed fluctuation is within the preset threshold, the vehicle is determined to be in a constant speed condition. When it is detected that within a preset first time window, the absolute value of the rate of change of engine speed continuously exceeds a first preset threshold, and the vehicle speed fluctuation exceeds the preset threshold, and the engine torque and accelerator pedal opening show an increase or decrease in the same direction, the vehicle is determined to be in an acceleration / deceleration condition.

3. The method for automatic adjustment of active noise reduction weights in a commercial vehicle cab according to claim 2, characterized in that, The steps in S33 for initially determining the control weights of the active noise cancellation system for each noise frequency band include: S331. Based on the contribution analysis results of S32, control weights are assigned to each noise frequency band according to the principle that the greater the contribution of the noise frequency band, the higher the control weight is assigned. S332. For each combination of vehicle load state and operating condition, generate a corresponding noise reduction weight matrix. The noise reduction weight matrix defines the initial control weight of the active noise reduction system for each target noise frequency band under the corresponding combination state. S333. Store the set of denoising weight matrices for all combined states as the calibration module.

4. The method for automatic adjustment of active noise reduction weights in a commercial vehicle cab according to claim 3, characterized in that, In S4, the steps of identifying the positional distribution of the occupants and determining one or more target areas requiring noise reduction by using gravity sensing modules installed at multiple locations within the driver's cab include: S41a, Read the output signals of the gravity sensor modules installed in the driver's seat, passenger seat and sleeper berth of the cab respectively; S41b: Compare the output signal of the gravity sensor module at each location with a preset weight threshold. If the signal value exceeds the weight threshold, it is determined that there is a passenger at that location. S41c: Based on the judgment result of S41b, all locations with occupants and adjacent areas acoustically associated with the locations are identified as target areas for noise reduction in this round of noise reduction cycle.

5. The method for automatic adjustment of active noise reduction weights in a commercial vehicle cab according to claim 4, characterized in that, The acoustic requirement mapping relationship includes: When it is detected that there is only an occupant in the driver's seat, the weight adjustment coefficient mapped to the engine order noise frequency band of the target area of ​​the driver's seat is greater than 1, while the adjustment coefficient for other frequency bands is equal to or less than 1. When a passenger is detected at a sleeper berth, the weighting adjustment coefficient for the broadband noise mapped to the target area of ​​the sleeper berth is greater than 1, while the adjustment coefficient for other frequency bands is equal to or less than 1.

6. The method for automatic adjustment of active noise reduction weights in a commercial vehicle cab according to claim 5, characterized in that, In S6, the specific steps for calculating the canceling sound wave signals that each speaker in the driver's cab needs to emit include: S61, Invoke the pre-stored sound transfer function from each speaker to each target area; S62. Based on the final noise reduction weight allocation information, calculate and synthesize the cancellation sound wave signals that each speaker needs to emit for different target areas.

7. A commercial vehicle cab active noise reduction weight automatic adjustment system, used to implement the method as described in any one of claims 1 to 6, characterized in that, include: The vehicle status judgment module is used to acquire the reference signals of the whole vehicle in real time and judge the current operating condition of the vehicle based on the reference signals. The load status acquisition module is used to acquire the vehicle load status through the vehicle bus. The calibration module pre-stores the initial control weights of the active noise cancellation system for each noise frequency band under different vehicle load conditions and different operating conditions. The preliminary weight query module is connected to the vehicle status judgment module, the load status acquisition module and the calibration module, and is used to retrieve the corresponding preliminary control weights from the calibration module according to the current operating conditions and vehicle load status. The fine-grained weight calculation module has its input end connected to a gravity sensing module and an error microphone located at multiple positions in the driver's cab. It is used to generate fine-grained adjustment weights for different noise frequency bands in different target areas based on the target area determined by the distribution of driver and passenger positions identified by the gravity sensing module and the in-vehicle noise signal collected in real time by the error microphone. The weight fusion module, connected to the preliminary weight query module and the refined weight calculation module, is used to fuse the preliminary control weights and the refined adjustment weights to generate final noise reduction weight allocation information for each noise frequency band. The noise reduction execution module is connected to the weight fusion module and is used to input the final noise reduction weight allocation information to the active noise reduction system. The active noise reduction system calculates the cancellation sound wave signal that each speaker in the driver's cab needs to emit, and drives the speaker array to emit the cancellation sound wave signal through the speaker control system.

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