Cabin noise reduction headrest device

Abstract

The invention discloses a cockpit noise reduction headrest device, and relates to the technical field of headrest noise reduction, the cockpit noise reduction headrest device comprises noise reduction headrests, a central processing unit and a daisy chain audio bus, each noise reduction headrest comprises a microphone assembly, a loudspeaker assembly and a first audio transceiver; the central processing unit comprises a digital signal processor and a second audio transceiver; the microphone assembly is used for collecting an environmental noise signal in a cabin, so that the environmental noise signal is transmitted to the central processing unit through the first audio transceiver and the daisy chain audio bus; the digital signal processor is used for carrying out feature recognition on the received environment noise signal and generating a corresponding reverse wave signal, and the central processing unit is used for sending the reverse wave signal to the corresponding noise reduction headrest through the daisy chain audio bus and the second audio transceiver, so that the noise reduction headrest drives the loudspeaker assembly to emit a reverse sound wave. The problem that a headrest device in the prior art only provides a single noise reduction function for a driving position is solved.

Description

Technical Field

[0001] This invention relates to the field of headrest noise reduction technology, and more particularly to a cabin noise reduction headrest device. Background Technology

[0002] With the development of the automotive industry and the improvement of consumer demand, passengers' requirements for cabin comfort are increasing. A good cabin acoustic environment not only helps to improve the riding experience and alleviate travel fatigue, but also significantly improves the clarity of in-vehicle voice communication, ensures the accuracy of voice command recognition, and helps passengers to more clearly perceive key audio information such as entertainment, navigation prompts, and safety warnings, thus playing a positive role in improving driving safety.

[0003] Existing automotive cabin noise reduction technologies mainly fall into two categories: passive noise reduction and active noise reduction. Active noise reduction technology effectively cancels out ambient noise by collecting it and generating a reverse sound wave with the opposite phase, and has already been applied in some mid-to-high-end models. However, existing in-vehicle active noise reduction solutions are mostly based on the vehicle's audio system, with speakers typically installed in fixed locations such as doors and dashboards, which are far from passengers' ears and susceptible to effects such as sound field reflection and interference within the cabin, resulting in limited noise reduction effectiveness, especially in environments with multiple passengers where balanced and precise noise control is difficult to achieve. Furthermore, most of the few headrest devices on the market that integrate active noise reduction are designed for the single driver's seat, providing noise reduction only for the driver and neglecting the noise reduction needs of front-seat and rear-seat passengers.

[0004] It is evident that existing headrest devices have the problem of only providing a single noise reduction function for the driver's seat. Summary of the Invention

[0005] The purpose of this invention is to provide a cabin noise reduction headrest device that solves the problem that existing headrest devices only provide a single noise reduction function for the driver's seat.

[0006] To achieve this objective, the present invention adopts the following technical solution: A cabin noise-canceling headrest device includes a noise-canceling headrest, a central processing unit, and a daisy-chain audio bus. Multiple noise-canceling headrests are distributed within the external cabin. Each noise-canceling headrest includes a microphone assembly, a speaker assembly, and a first audio transceiver. The central processing unit is located within the vehicle's central control unit and includes a digital signal processor and a second audio transceiver. Multiple noise-canceling headrests are connected in series to the central processing unit via the daisy-chain audio bus to form a centralized active noise cancellation system. The microphone assembly is used to collect ambient noise signals within the cabin, and transmits these signals to the central processing unit via the first audio transceiver and the daisy-chain audio bus. The digital signal processor is used to perform feature recognition on the received ambient noise signals and generate corresponding reverse wave signals. The central processing unit is used to send the reverse wave signals to the corresponding noise-canceling headrest via the daisy-chain audio bus and the second audio transceiver, so that the noise-canceling headrest drives its speaker assembly to emit reverse sound waves.

[0007] Optionally, each of the noise-canceling headrests further includes a detachably connected headrest main shell and a headrest back cover, wherein a headrest control board is installed inside the headrest main shell, and the power amplifier circuits of the first audio transceiver and the speaker assembly are integrated on the headrest control board.

[0008] Optionally, the microphone assembly includes multiple microphone sensors for directional acquisition of ambient noise, with some of the microphone sensors distributed on the front of the noise-canceling headrest, some of the microphone sensors distributed on the bottom of the noise-canceling headrest, and another portion of the microphone sensors distributed on the back of the noise-canceling headrest.

[0009] Optionally, two of the microphone sensors are located on one side of the back of the noise-canceling headrest, and the other two microphone sensors are located on the other side of the back of the noise-canceling headrest, with a 60-degree pointing angle between the two microphone sensors on either side of the back.

[0010] Optionally, the speaker assembly includes two speakers oppositely distributed on the front of the noise-canceling headrest, the two speakers being close to the ears of the cabin user, and each speaker being electrically connected to a corresponding power amplifier circuit of the noise-canceling headrest.

[0011] Optionally, the central processing unit further includes a central processing unit communicatively connected to the digital signal processor, the central processing unit being used to load noise feature recognition algorithms and control instructions onto the digital signal processor.

[0012] Optionally, the digital signal processor may pre-store or receive a noise feature library from the central processing unit, the noise feature library including tire noise, wind noise, motor noise and engine noise; The digital signal processor is used to compare the ambient noise signal collected by the speaker assembly with the noise feature library to identify characteristic noise, and generate the reverse wave signal based on the identified characteristic noise; the digital signal processor is also used to maintain the transmission of background noise that is not identified as characteristic noise, the background noise including human voice and music.

[0013] Optionally, the central processing unit is also connected to an in-vehicle environment sensor, which is used to collect at least one of vibration signals, temperature signals and air pressure signals in the cabin. The digital signal processor is also used to perform weighted correction on the identification results of the characteristic noise based on the signals collected by the in-vehicle environment sensor, so as to dynamically adjust the generation parameters of the reverse wave signal.

[0014] Optionally, the noise-canceling headrest is a movable headrest, which is movably inserted into the back of the cabin; when the noise-canceling headrest is installed in place, it is electrically connected to the daisy-chain audio bus.

[0015] Optionally, the cabin noise-canceling headrest device further includes a backup audio channel, which is independent of the daisy-chain audio bus; the central processing unit is also used to continuously monitor the communication status of the daisy-chain audio bus and the feedback signals of each of the noise-canceling headrests. When the central processing unit detects a malfunction in the daisy-chain audio bus or an abnormal signal in at least one of the noise-canceling headrests, the central processing unit switches to the backup audio channel and sends a noise-canceling control signal or a general reverse wave signal to one or more designated noise-canceling headrests through the backup audio channel.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a cabin noise-canceling headrest device. By distributing multiple noise-canceling headrests across various passenger positions in the cabin, and independently equipping each headrest with a microphone and speaker assembly, it can perform real-time noise acquisition and reverse sound wave playback targeting the local sound field at the ears of passengers in different seats. Combined with the centralized processing and independent feedback control of multiple noise signals by a central processing unit, it can provide each passenger with a balanced active noise cancellation service tailored to their position. Since the speaker assembly is directly integrated inside the headrest and close to the passenger's ear, the propagation path of the reverse sound wave is greatly shortened, reducing sound wave reflection, attenuation, and interference within the cabin, thereby improving the timeliness and accuracy of noise cancellation. By using a daisy-chain audio bus to connect multiple noise-canceling headrests to the central processing unit, the number and complexity of wiring harnesses required by traditional parallel wiring are significantly reduced, lowering installation costs and the risk of failure. Since the central processing unit is located within the vehicle's central control equipment, it facilitates the use of existing vehicle computing resources and power management, reducing the cost of the headrest device. Therefore, this invention solves the problem of existing headrest devices that only provide a single noise cancellation function for the driver's seat. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0019] Figure 1 A structural frame for a cabin noise reduction headrest device provided in an embodiment of the present invention. Figure 1 ; Figure 2 A structural frame for a cabin noise reduction headrest device provided in an embodiment of the present invention. Figure 2 ; Figure 3 A structural frame for a cabin noise reduction headrest device provided in an embodiment of the present invention. Figure 3 ; Figure 4 A three-dimensional structural diagram of the headrest in a cabin noise reduction headrest device provided in an embodiment of the present invention. Figure 1 ; Figure 5 A three-dimensional structural diagram of the headrest in a cabin noise reduction headrest device provided in an embodiment of the present invention. Figure 2 ; Figure 6 This is an exploded structural diagram of a headrest in a cabin noise reduction headrest device provided in an embodiment of the present invention; Figure 7 A schematic diagram of the circuit principle of the central processing unit of a cabin noise reduction headrest device provided in an embodiment of the present invention.

[0020] Illustration: 10. Noise-canceling headrest; 11. Headrest main shell; 12. Headrest back cover; 13. Headrest control panel; 14. Microphone sensor; 15. Speaker; 20. Central processing unit; 21. Digital signal processor; 22. Second audio transceiver; 23. Central processing unit; 30. Daisy-chain audio bus; 40. In-vehicle environment sensor; 50. Backup audio channel. Detailed Implementation

[0021] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] This invention provides a cabin noise reduction headrest device, such as... Figures 1 to 7 As shown, the system includes noise-canceling headrests 10, a central processing unit 20, and a daisy-chain audio bus 30. Multiple noise-canceling headrests 10 are distributed in the external cabin, and each noise-canceling headrest 10 includes a microphone assembly, a speaker assembly, and a first audio transceiver. The central processing unit 20 is located in the vehicle's central control unit and includes a digital signal processor 21 and a second audio transceiver 22. Multiple noise-canceling headrests 10 are connected in series to the central processing unit 20 via the daisy-chain audio bus 30 to form a centralized active noise cancellation system. The microphone assembly is used to collect ambient noise signals within the cockpit, transmitting these signals to the central processing unit 20 via a first audio transceiver and a daisy-chain audio bus 30. A digital signal processor 21 performs feature recognition on the received ambient noise signals and generates corresponding reverse wave signals. The central processing unit 20 then sends these reverse wave signals to the corresponding noise-canceling headrest 10 via the daisy-chain audio bus 30 and the second audio transceiver 22, thereby driving the speaker assembly of the noise-canceling headrest 10 to emit reverse sound waves. In this embodiment, the daisy-chain audio bus 30 (also referred to as an audio daisy-chain bus) refers to an audio signal transmission bus employing a daisy-chain topology.

[0025] It should be noted that the cabin noise-canceling headrest device provided by this invention distributes multiple noise-canceling headrests 10 at various passenger positions in the cabin, and independently equips each headrest with a microphone assembly and a speaker assembly. This enables real-time noise acquisition and reverse sound wave playback of the local sound field at the ears of passengers in different seats. Combined with the centralized processing and independent feedback control of multiple noise signals by the central processing unit 20, it can provide each passenger with a balanced active noise cancellation service matched to their position. Since the speaker assembly is directly integrated inside the headrest and close to the passenger's ear, the propagation path of the reverse sound wave is greatly shortened, reducing sound wave reflection, attenuation, and interference in the cabin, thereby improving the timeliness and accuracy of noise cancellation. By using a daisy-chain audio bus 30 to connect multiple noise-canceling headrests 10 in series to the central processing unit 20, the number and complexity of the wiring harness required by traditional parallel wiring are greatly reduced, lowering installation costs and failure risks. Since the central processing unit 20 is located in the vehicle's central control equipment, it is convenient to utilize the vehicle's existing computing resources and power management, reducing the cost of the headrest device. Therefore, the present invention solves the problem that the headrest device in the prior art only provides a single noise reduction function for the driver's seat.

[0026] like Figures 4 to 6 As shown, each noise-canceling headrest 10 also includes a detachably connected headrest main shell 11 and a headrest back cover 12. A headrest control board 13 is installed inside the headrest main shell 11, and the power amplifier circuits for the first audio transceiver and speaker assembly are integrated on the headrest control board 13. The noise-canceling headrest 10 is a movable headrest, movably inserted into the backrest of the cabin; when the noise-canceling headrest 10 is installed in place, it is electrically connected to the daisy-chain audio bus 30. In this embodiment, the headrest main shell 11 and the headrest back cover 12 are fastened together by screws or secured by snap-fit.

[0027] In practical implementation, the noise-canceling headrest 10 adopts a detachable headrest main shell 11 and headrest rear cover 12, facilitating the installation, maintenance, or replacement of internal components (such as the headrest control board 13, speakers 15, etc.) and reducing maintenance costs. Simultaneously, the first audio transceiver and the speaker assembly's power amplifier circuit are integrated onto the headrest control board 13, reducing internal wiring, improving circuit stability and anti-interference capabilities, and ensuring the quality of audio signal transmission. The noise-canceling headrest 10 features a movable design, allowing it to be inserted into the seat back, enabling the headrest position to be adaptively adjusted according to passenger body shape, seating habits, or seat adjustments, ensuring that the speakers 15 are always in the optimal acoustic position. This design also allows the headrest to be flexibly configured for different vehicle models or cabin layouts, improving the product's versatility.

[0028] like Figures 4 to 6As shown, the microphone assembly includes multiple microphone sensors 14 for directional acquisition of ambient noise. Some of the microphone sensors 14 are located on the front of the noise-canceling headrest 10, some on the bottom surface of the noise-canceling headrest 10, and others on the back surface of the noise-canceling headrest 10. Specifically, two microphone sensors 14 are located on one side of the back surface of the noise-canceling headrest 10, and two other microphone sensors 14 are located on the other side of the back surface of the noise-canceling headrest 10. The two microphone sensors 14 on either side of the back surface have a 60-degree pointing angle. Four microphone sensors 14 are located on the front of the noise-canceling headrest 10, and two microphone sensors 14 are located on the bottom surface of the noise-canceling headrest 10.

[0029] In practical implementation, a three-dimensional acoustic sampling network surrounding the passenger's head is constructed by distributing multiple microphone sensors 14 on the front, bottom, and back of the headrest. This design can simultaneously collect environmental noise from different directions, including the front (e.g., engine and wind noise), the rear and sides (e.g., rear seat noise and ambient sound), and the bottom (cabin-reflected sound and chassis road noise), thus comprehensively and realistically reproducing the complex acoustic environment in which the passenger's ears are located, providing a complete sound field data foundation for subsequent accurate noise cancellation. Microphones are symmetrically arranged on both sides of the back of the headrest, with a specific 60-degree pointing angle between the two microphone sensors 14 on each side. This structure essentially forms a small directional acquisition array. This design not only effectively collects rear noise but also assists the system in determining the lateral direction of the noise source by comparing the phase and intensity differences of the microphone signals on both sides, improving the ability to locate and distinguish lateral and rear noise sources.

[0030] Furthermore, the multi-directionally distributed microphone array reduces blind spots in sound field sampling caused by slight head movements or posture changes in passengers, ensuring that the system can continuously acquire effective noise reference signals under any seating conditions. Simultaneously, the dedicated acquisition of reflected sound from the floor (typically facing the cabin interior) helps the system identify and process reverberant acoustic components formed by multiple reflections within the cabin. This further optimizes the control of reverberant noise beyond simply canceling direct noise, enhancing the overall clarity and naturalness of the noise reduction experience.

[0031] like Figures 4 to 6 As shown, the speaker assembly includes two speakers 15 opposite to each other on the front of the noise-canceling headrest 10. The two speakers 15 are close to the ears of the cabin user, and each speaker 15 is electrically connected to a corresponding power amplifier circuit of the noise-canceling headrest 10.

[0032] In practice, two speakers 15 are positioned opposite each other on the front of the headrest, close to the user's ears, forming a near-field and direct sound wave emission unit. This design allows the generated reverse sound waves to act directly on the area near the ear canal with the shortest path and lowest attenuation, achieving rapid and precise cancellation with the noise signal collected by the microphone. This significantly reduces the problems of sound wave propagation delay, path complexity, and energy attenuation in traditional far-field speaker 15 solutions, thereby achieving deeper and more timely noise cancellation over a wider frequency range (especially mid-to-high frequencies). Each speaker 15 is independently connected to the corresponding power amplifier circuit on the headrest control board 13, meaning that the central processing unit 20 can perform independent signal analysis and beamforming (or channel balancing) control on the left and right channels through the digital signal processor 21. When the system identifies that the noise mainly comes from one side of the passenger (such as wind noise from a single side window), it can dynamically adjust the output strategy of the left and right speakers 15 to achieve more targeted asymmetric noise reduction, improving the system's intelligence and flexibility in dealing with complex dynamic noise environments.

[0033] like Figures 1 to 3 As shown, the central processing unit 20 also includes a central processing unit 23 communicatively connected to the digital signal processor 21. The central processing unit 23 is used to load noise feature recognition algorithms and control instructions onto the digital signal processor 21. The digital signal processor 21 pre-stores or receives a noise feature library from the central processing unit 20. The noise feature library includes tire noise, wind noise, motor noise, and engine noise. The digital signal processor 21 is used to compare the ambient noise signal collected by the speaker assembly with a noise feature library to identify characteristic noise, and generate a reverse wave signal based on the identified characteristic noise. The digital signal processor 21 is also used to maintain the transmission of background noise that is not identified as characteristic noise, including human voices and music. In this embodiment, the noise feature recognition algorithm is a well-known algorithm in the art and will not be described in detail here.

[0034] In practical implementation, by setting up a noise feature library containing typical cabin noise characteristics such as tire noise, wind noise, motor noise, and engine noise, the digital signal processor 21 can accurately compare and extract features from the mixed environmental noise signals collected by the microphone with the noise feature library. This allows the system to intelligently distinguish the annoying steady-state or characteristic mechanical noise that needs to be canceled, and to generate a matching reverse wave signal accordingly. This achieves a leap from indiscriminate noise reduction to selective and precise noise reduction, greatly improving the targeting and effectiveness of noise reduction. The digital signal processor 21 is configured to maintain transparency of background sounds (such as human voices and music) that are not identified as characteristic noise. This avoids the drawbacks of traditional active noise cancellation systems that may interfere with or weaken voice calls, entertainment audio, or important warning sounds. While enjoying a quiet environment, users can have clear conversations, listen to music, or receive navigation prompts without hindrance. This truly achieves the intelligent acoustic management goal of noise reduction without degrading sound quality and quietness without silence, greatly enhancing safety and the riding experience.

[0035] It should be noted that by adopting a collaborative architecture of central processing unit 23 and digital signal processor 21, efficient task division is achieved. Central processing unit 23 is responsible for loading upper-level algorithms, system control, and feature library management, while digital signal processor 21 focuses on low-level high-speed real-time audio signal processing and feature matching operations. This architecture fully leverages the expertise and speed advantage of digital signal processor 21 in digital signal processing, ensuring rapid response to dynamic noise and extremely low latency in reverse wave generation, while reducing the load on central processing unit 23, making the system operation more stable and efficient.

[0036] like Figures 1 to 3 As shown, the central processing unit 20 is also connected to an in-vehicle environment sensor 40, which is used to collect at least one of vibration signals, temperature signals and air pressure signals in the cabin. The digital signal processor 21 is also used to perform weighted correction on the identification results of characteristic noise based on the signals collected by the in-vehicle environment sensor 40, so as to dynamically adjust the generation parameters of the reverse wave signal.

[0037] In specific implementation, the central processing unit 20 in this embodiment is connected to a set of in-vehicle environment sensors 40 via a vehicle bus (such as CAN FD or Ethernet). Vibration sensors are installed at key locations such as the vehicle chassis longitudinal beams, subframe, or seat rails to collect low-frequency structural vibration signals from road surface excitation (corresponding to tire noise and road noise) and powertrain (corresponding to engine and motor vibration noise); their output is an electrical signal related to vibration acceleration or frequency. Air pressure sensors are installed near the A-pillar, exterior rearview mirror base, or windows to sense air pressure fluctuations inside and outside the cabin caused by high-speed vehicle travel and changes in window opening / closing status. These fluctuations are the main excitation source for wind noise generation and propagation. Temperature sensors can be integrated into the air conditioning vents or cabin interior panels to monitor cabin temperature; this signal is mainly used indirectly to correct for changes in sound wave propagation speed caused by temperature changes and to assist in identifying noise characteristics caused by changes in the operating status of the air conditioning system compressor and fan.

[0038] The raw analog signals collected by the aforementioned sensors are preprocessed by their respective signal conditioning circuits (such as amplification and filtering) and then transmitted to the central processing unit 20 via the vehicle bus. The central processing unit 23 receives these signals and performs preliminary calibration, normalization, and time synchronization to ensure alignment with the audio signals collected by the microphone on the time axis. The preprocessed data from the in-vehicle environment sensors 40 is input to the digital signal processor 21, fused with a noise feature recognition algorithm, and performs the following dynamic correction steps: In the confidence weighting step, the algorithm within the digital signal processor 21 assigns an initial confidence level to the noise feature identification result (e.g., "the current main noise component is second-order engine noise at 80Hz"). Simultaneously, a correction weight is calculated based on the environmental sensor signal. In this embodiment, when the vibration sensor detects a strong vibration signal synchronized with the engine ignition frequency in the 40-200Hz frequency band, the signal increases the confidence weight of the identification result as "engine noise". When the vehicle speed is high (from the CAN bus) and the air pressure sensor detects a specific high-frequency fluctuation pattern, the signal enhances the identification weight of the "wind noise" feature, even if other noises may be mixed in the audio spectrum at this time.

[0039] In the parameter dynamic adjustment step, based on the weighted comprehensive identification result, the digital signal processor 21 dynamically adjusts the step size of the subsequent adaptive filtering algorithm (such as FxLMS) or the update rate of the filter. In this embodiment, when tire noise is identified and the vibration signal shows severe road surface excitation, the digital signal processor 21 increases the control bandwidth of the low frequency band and the algorithm convergence speed to quickly track the changing tire noise.

[0040] In the step of generating an optimized reverse wave signal, the digital signal processor 21 uses a control algorithm that has been corrected by sensor data and optimized by parameters to generate a reverse wave digital signal that best matches the current comprehensive working conditions, and sends it down to the corresponding noise-reducing headrest 10 through a daisy-chain bus.

[0041] It should be noted that relying solely on microphone audio signals can sometimes be insufficient to accurately separate sound sources in complex mixed noise (for example, low-frequency engine noise and low-frequency tire noise caused by rough road surfaces may overlap in the audio spectrum). By introducing source signals directly related to the physical level, such as vibration and air pressure, this multi-dimensional perception of sound, vibration, and pressure effectively avoids the problems of single audio signals being susceptible to interference and identification ambiguity, making the identification results of characteristic noise closer to physical reality and laying a reliable data foundation for accurate cancellation. Environmental sensors (especially vibration and air pressure sensors) can often detect changes in noise excitation sources earlier and more directly than microphone sensors. For example, the impact vibration of a tire passing over a seam will reach the ear slightly earlier than the resulting thud. The system can utilize this small time difference to predict noise characteristics in advance and fine-tune algorithm parameters, thereby significantly shortening the system response delay and improving the cancellation effect of transient noise.

[0042] like Figures 1 to 3 As shown, the cabin noise-canceling headrest 10 device also includes a backup audio channel 50, which is independent of the daisy-chain audio bus 30; the central processing unit 20 is also used to continuously monitor the communication status of the daisy-chain audio bus 30 and the feedback signals of each noise-canceling headrest 10. When the central processing unit 20 detects a malfunction in the daisy-chain audio bus 30 or an abnormal signal in at least one noise-canceling headrest 10, the central processing unit 20 switches to the backup audio channel 50 and sends noise-canceling control signals or general reverse wave signals to one or more designated noise-canceling headrests 10 through the backup audio channel 50.

[0043] In practice, the backup audio channel 50 is a physical or logical communication path independent of the daisy-chain audio bus 30. It can be an independent wired backup channel; for example, it can be pre-deployed from the central processing unit 20 to each noise-canceling headrest 10, or at least to the headrests in key positions such as the driver's seat and the passenger seat, using existing in-vehicle Ethernet, MOST bus or dedicated shielded audio cables in the vehicle; or it can be a wireless backup channel, such as a point-to-point wireless link established between the central processing unit 20 and each noise-canceling headrest 10 based on a proprietary protocol or ultra-wideband based on the 5.9GHz band.

[0044] This design employs a redundant architecture to ensure that the noise reduction function is not completely interrupted in the event of any anticipated or unexpected failure in the main communication link. The system can seamlessly or temporarily switch to a backup channel after an interruption, continuing to provide valuable noise reduction services and guaranteeing continuity of functionality and user peace of mind. The system can intelligently distinguish between global bus failures and local node failures and adopt different response strategies.

[0045] Working Principle: This invention provides a cabin noise-canceling headrest device. By distributing multiple noise-canceling headrests 10 across various passenger positions in the cabin, and independently equipping each headrest with a microphone and speaker assembly, it can perform real-time noise acquisition and reverse sound wave playback for the local sound field at the ears of passengers in different seats. Combined with the centralized processing and independent feedback control of multiple noise signals by the central processing unit 20, it can provide each passenger with a balanced active noise cancellation service matched to their position. Since the speaker assembly is directly integrated inside the headrest and close to the passenger's ear, the propagation path of the reverse sound wave is greatly shortened, reducing sound wave reflection, attenuation, and interference within the cabin, thereby improving the timeliness and accuracy of noise cancellation. By using a daisy-chain audio bus 30 to connect multiple noise-canceling headrests 10 in series to the central processing unit 20, the number and complexity of wiring harnesses required by traditional parallel wiring are significantly reduced, lowering installation costs and failure risks. Since the central processing unit 20 is located within the vehicle's central control equipment, it is convenient to utilize the vehicle's existing computing resources and power management, reducing the cost of the headrest device. Therefore, the present invention solves the problem that the headrest device in the prior art only provides a single noise reduction function for the driver's seat.

[0046] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cabin noise reduction headrest device, characterized in that, The system includes noise-canceling headrests, a central processing unit, and a daisy-chain audio bus. Multiple noise-canceling headrests are distributed within the external cabin, and each headrest includes a microphone assembly, a speaker assembly, and a first audio transceiver. The central processing unit is located within the vehicle's central control unit and includes a digital signal processor and a second audio transceiver. Multiple noise-canceling headrests are connected in series to the central processing unit via the daisy-chain audio bus to form a centralized active noise cancellation system. The microphone assembly is used to collect ambient noise signals within the cabin, and transmits these signals to the central processing unit via the first audio transceiver and the daisy-chain audio bus. The digital signal processor is used to perform feature recognition on the received ambient noise signals and generate corresponding reverse wave signals. The central processing unit is used to send the reverse wave signals to the corresponding noise-canceling headrest via the daisy-chain audio bus and the second audio transceiver, so that the noise-canceling headrest drives its speaker assembly to emit reverse sound waves.

2. The cabin noise reduction headrest device according to claim 1, characterized in that, Each of the noise-canceling headrests also includes a detachably connected headrest main shell and a headrest back cover. A headrest control board is installed inside the headrest main shell, and the power amplifier circuits of the first audio transceiver and the speaker assembly are integrated on the headrest control board.

3. The cabin noise reduction headrest device according to claim 1 or 2, characterized in that, The microphone assembly includes multiple microphone sensors for directional acquisition of ambient noise. Some of the microphone sensors are distributed on the front of the noise-canceling headrest, some are distributed on the bottom of the noise-canceling headrest, and other microphone sensors are distributed on the back of the noise-canceling headrest.

4. The cabin noise reduction headrest device according to claim 3, characterized in that, Two of the microphone sensors are located on one side of the back of the noise-canceling headrest, and the other two microphone sensors are located on the other side of the back of the noise-canceling headrest. The two microphone sensors on either side of the back have a 60-degree pointing angle between them.

5. The cabin noise reduction headrest device according to claim 1, characterized in that, The speaker assembly includes two speakers positioned opposite each other on the front of the noise-canceling headrest, with the two speakers close to the user's ears, and each speaker electrically connected to a corresponding amplifier circuit of the noise-canceling headrest.

6. The cabin noise reduction headrest device according to claim 1, 2, or 5, characterized in that, The central processing unit further includes a central processing unit that is communicatively connected to the digital signal processor, the central processing unit being used to load noise feature recognition algorithms and control instructions onto the digital signal processor.

7. The cabin noise reduction headrest device according to claim 6, characterized in that, The digital signal processor pre-stores or receives a noise feature library from the central processing unit, the noise feature library including tire noise, wind noise, motor noise and engine noise; The digital signal processor is used to compare the ambient noise signal collected by the speaker assembly with the noise feature library to identify characteristic noise, and generate the reverse wave signal based on the identified characteristic noise; the digital signal processor is also used to maintain the transmission of background noise that is not identified as characteristic noise, the background noise including human voice and music.

8. The cabin noise reduction headrest device according to claim 7, characterized in that, The central processing unit is also connected to an in-vehicle environment sensor, which is used to collect at least one of vibration signals, temperature signals and air pressure signals in the cabin. The digital signal processor is also used to perform weighted correction on the identification results of the characteristic noise based on the signals collected by the in-vehicle environment sensor, so as to dynamically adjust the generation parameters of the reverse wave signal.

9. The cabin noise reduction headrest device according to claim 1, characterized in that, The noise-canceling headrest is a movable headrest, which is movably inserted into the back of the cabin; when the noise-canceling headrest is installed in place, it is electrically connected to the daisy-chain audio bus.

10. The cabin noise reduction headrest device according to claim 1, characterized in that, The cabin noise-canceling headrest device also includes a backup audio channel, which is independent of the daisy-chain audio bus; the central processing unit is also used to continuously monitor the communication status of the daisy-chain audio bus and the feedback signals of each of the noise-canceling headrests. When the central processing unit detects a malfunction in the daisy-chain audio bus or an abnormal signal in at least one of the noise-canceling headrests, the central processing unit switches to the backup audio channel and sends a noise-canceling control signal or a general reverse wave signal to one or more designated noise-canceling headrests through the backup audio channel.

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