Vehicle-mounted loudspeaker capable of adjusting pointing angle and control method thereof

Abstract

The invention discloses a vehicle-mounted loudspeaker capable of adjusting a pointing angle and a control method thereof, and relates to the technical field of automotive electronics and electroacoustics, and the vehicle-mounted loudspeaker comprises an in-vehicle microphone array, a main control unit, an electric lifting and rotating loudspeaking unit, an auxiliary loudspeaking unit and a self-adaptive digital signal processing power amplifier. The main control unit collects a voice signal, identifies an instruction intention, and calculates the head center coordinate of a sound production passenger; and planning a physical path according to the instruction and the coordinates, and generating an angle control instruction. Executing acoustic parameter coupling calculation: calculating a delay amount in a high-fidelity mode; a diffusion field equalization parameter is configured in a surrounding mode; and calculating the gain and the phase delay of the auxiliary loudspeaker in the privacy mode. And the main control unit synchronously drives the loudspeaker to perform mechanical action and DSP signal processing. According to the method, deterministic mapping of the mechanical degree of freedom and the acoustic parameters is established, dynamic reconstruction of the acoustic path in the vehicle is achieved, the problem of acoustic image positioning drift is effectively solved, and auditory experience is improved.

Description

An adjustable pointing angle vehicle speaker and its control method Technical Field

[0001] This application relates to the fields of automotive electronics and electroacoustics, and in particular to an adjustable pointing angle vehicle speaker and its control method. Background Technology

[0002] With the development of intelligent automotive cockpits, users have placed higher demands on the personalization and immersion of the in-car auditory experience. To improve sound quality, modern car audio systems typically deploy a large number of speaker units inside the vehicle. However, due to the limited and complex acoustic environment inside the car, the placement of in-car speakers is usually fixed in locations such as the doors, A-pillars, or dashboard.

[0003] Because high-frequency sound waves are highly directional, when the main axis of a loudspeaker's radiation is not precisely aligned with the occupant's ear, the attenuation of the off-axis response leads to the loss of high-frequency information, resulting in blurred sound image localization. Although some loudspeaker devices with mechanical lifting or rotating functions have appeared on the market, these devices often only focus on demonstrating the movement of the mechanical structure or adjusting a single angle, ignoring the acoustic parameter mismatch caused by the change in sound wave transmission distance after the physical position of the loudspeaker changes.

[0004] When a speaker undergoes mechanical displacement, if the time delay and phase of the audio signal are not synchronously corrected, the sound waves reaching the human ear will experience phase interference and comb filtering effects, which will actually reduce the listening quality.

[0005] Furthermore, creating a sense of spatial sound field within the vehicle is a major bottleneck for current technology. Traditional car audio systems primarily rely on direct sound for coverage, which often results in a thin and lacking width within the confined space of the cabin. Existing technology lacks active control mechanisms for acoustic reflection using hard surfaces such as car windows, making it impossible to expand the auditory boundaries of the sound field by constructing virtual sound sources. Consequently, it struggles to meet users' needs for a wide and immersive sound field when watching movies or enjoying symphonies.

[0006] Meanwhile, achieving independent privacy sound zones in the compact, open space of a car remains technically challenging. Existing zone sound technology largely relies on simple signal gain attenuation or complex digital beamforming algorithms. However, simply adjusting volume balance cannot physically isolate sound propagation, and purely digital algorithms, without physical directivity, struggle to create high signal-to-noise ratio quiet zones in nearby adjacent areas. This results in sound leakage to adjacent areas when the driver makes private calls or passengers engage in independent entertainment, failing to achieve effective sound field isolation. Summary of the Invention

[0007] The purpose of this invention is to provide an adjustable pointing angle vehicle speaker and its control method, which at least solves a technical problem in existing vehicle speaker systems that makes it difficult to achieve dynamic coordination between mechanical pointing and signal parameters, resulting in phase distortion caused by physical displacement, and is unable to effectively utilize environmental reflections to expand the sound field width, making it difficult to achieve high isolation and privacy partitioning in open cabins.

[0008] The first aspect of this invention provides an adjustable pointing angle vehicle speaker. The vehicle speaker device includes an in-vehicle microphone array, a main control unit, an electrically operated lifting and rotating speaker unit, an auxiliary speaker unit, and an adaptive digital signal processing power amplifier.

[0009] The in-vehicle microphone array is configured to collect voice signals from the in-vehicle environment and convert the collected analog signals into digital signals.

[0010] The main control unit, as the core computing component, is configured to receive the digital signal and perform semantic analysis on the digital signal to identify the user's command intent.

[0011] Simultaneously, the main control unit uses a time difference of arrival (TDOA) algorithm to process digital signals to calculate the head center coordinates of the occupant. Based on the recognized command intent and the calculated head center coordinates, the main control unit plans the physical path of sound wave propagation, calculates the corresponding audio parameters, and then generates angle control commands and parameter configuration commands.

[0012] The electric lifting and rotating speaker unit is configured to respond to angle control commands sent by the main control unit and perform mechanical actions to adjust its own azimuth and pitch angles.

[0013] The auxiliary speaker unit is connected to an adaptive digital signal processing power amplifier and is used to emit sound waves in a specific mode.

[0014] The adaptive digital signal processing power amplifier is configured to receive parameter configuration instructions sent by the main control unit, process the input audio stream in real time according to the audio parameters in the instructions, and drive the electric lifting and rotating speaker unit and the auxiliary speaker unit to produce sound.

[0015] The main control unit is also used to construct a mapping relationship between the physical angle of the electric lifting and rotating speaker unit and the audio parameters of the adaptive digital signal processing power amplifier, so as to realize the reconstruction of the acoustic path in the vehicle.

[0016] The mapping relationship specifically includes associating the target physical pointing angle of the electric lifting and rotating speaker unit with the time delay, frequency response characteristics, or phase parameters of the audio stream, so that the audio parameters can be synchronously adapted to the changed in-vehicle acoustic path during the mechanical operation of the electric lifting and rotating speaker unit.

[0017] A second aspect of the present invention provides a control method for an adjustable pointing angle vehicle speaker. This method is applied to the adjustable pointing angle vehicle speaker described in the first aspect above. The control method mainly includes the following steps:

[0018] The main control unit acquires and converts digital signals collected by the in-vehicle microphone array, performs semantic analysis on the digital signals to identify the intent of the command, and uses the time difference of arrival algorithm to process the digital signals and calculate the head center coordinates of the occupant speaking.

[0019] During this process, the main control unit establishes a three-dimensional Cartesian coordinate system with the center of the vehicle chassis as the origin, and processes digital signals according to the sound source localization equation, which describes the quantitative relationship between the sound wave propagation time difference and the spatial geometric distance difference.

[0020] Next, the main control unit calculates the target physical pointing angle of the electric lifting and rotating speaker unit based on the instruction intent and the center coordinates of the head, and generates an angle control command.

[0021] Then, the main control unit performs acoustic parameter coupling calculations based on the physical path planning results corresponding to the target's physical pointing angle. Specifically, this process involves: identifying the acoustic mode corresponding to the command intent, calculating audio parameters based on the calculation strategy corresponding to the acoustic mode, and generating parameter configuration instructions.

[0022] Finally, the main control unit synchronously sends angle control commands and parameter configuration commands, which respectively drive the electric lifting and rotating speaker unit to perform mechanical actions and control the adaptive digital signal processing power amplifier to process the audio stream based on the audio parameters.

[0023] In the aforementioned control method, the specific process of identifying the instruction intent includes the main control unit performing semantic analysis on the digital signal and identifying whether the instruction intent is a high-fidelity mode, a surround mode, or a privacy mode. The acoustic modes include direct sound modes, reflected sound modes, and interference noise-canceling modes; high-fidelity mode corresponds to direct sound modes, surround mode corresponds to reflected sound modes, and privacy mode corresponds to interference noise-canceling modes.

[0024] When the instruction intent is high-fidelity mode, the main control unit calculates the direction vector from the current center position vector of the electrically raised and rotated speaker unit to the head center coordinate, and generates an angle control command to align the main lobe of the sound axis with the head center coordinate. Regarding audio parameter calculation, the main control unit calculates the dynamic delay amount based on a dynamic delay compensation equation, which is used to calculate the time delay compensation value required to eliminate the sound wave arrival time deviation caused by changes in physical distance.

[0025] When the command intent is surround mode, the main control unit calls the pre-stored 3D in-vehicle geometric model and uses the virtual source method to calculate the mirror image point of the head center coordinates with respect to the nearest rigid reflective surface. This generates an angle control command that directs the acoustic axis towards the mirror reflection point on the rigid reflective surface. Regarding audio parameter calculations, the main control unit generates configuration parameters to control the adaptive digital signal processing power amplifier to perform diffuse field equalization processing. These configuration parameters are used to increase the gain in the high-frequency band to compensate for sound wave reflection loss on the reflective surface.

[0026] When the instruction intent is privacy mode, the main control unit determines the head center coordinates of the non-target listening area based on the vehicle seat layout data, and calculates the sidelobe angle with the greatest sensitivity attenuation based on the directivity data of the electrically adjustable rotating speaker unit. Based on the head center coordinates of the non-target listening area, the main control unit generates an angle control instruction that aligns the sidelobe angle with the head center coordinates of the non-target listening area.

[0027] In terms of audio parameter calculation, the main control unit activates the auxiliary speaker unit corresponding to the non-target listening area, and calculates the required gain coefficient and additional phase delay of the auxiliary speaker unit according to the interference cancellation equation, and uses the gain coefficient and additional phase delay as audio parameters. The interference cancellation equation is used to calculate the signal parameters required to form a silent zone in the non-target listening area.

[0028] Furthermore, during the drive execution step, in the transition period when the electric lifting and rotating speaker unit performs mechanical actions, the adaptive digital signal processing power amplifier uses a linear interpolation algorithm to smoothly transition the current audio parameters to the target audio parameters, ensuring a smooth and continuous listening experience. The three-dimensional Cartesian coordinate system, the three-dimensional geometric model inside the vehicle, and the vehicle seat layout data involved in the above process are pre-set according to the vehicle's factory calibration parameters and stored in the main control unit's memory.

[0029] The above solution achieves the following beneficial technical effects:

[0030] This application solves the problem of sound image positioning drift caused by speaker displacement by establishing a deterministic mapping relationship between the physical angle of the electrically operated lifting and rotating speaker unit and the audio parameters of the adaptive digital signal processing power amplifier. While controlling the physical orientation of the speaker to align with the occupant, the system calculates and adjusts the time delay of the audio signal in real time based on a dynamic delay compensation equation, effectively compensating for the sound wave arrival time deviation caused by changes in physical distance. This synchronous coupling of the physical path and digital parameters suppresses phase distortion introduced by mechanical movement, ensuring a direct sound experience with zero off-axis response and strict phase alignment at the listening position in high-fidelity mode.

[0031] This application utilizes rigid interfaces within the vehicle to physically expand the width of the sound field. In surround mode, the system overcomes the limitations of traditional direct-fire speakers by using a virtual source method to calculate reflection paths, driving the speakers to point towards reflective surfaces such as side windows, and compensating for reflection losses with diffusion field equalization parameters. This technical solution transforms the limited physical space within the vehicle into acoustic reflection cavities, effectively increasing the auditory envelope by constructing virtual sound sources, and solving the acoustic coverage problem of highly directional speakers when creating a wide sound field.

[0032] This application improves the isolation effect of local sound fields by employing a dual control strategy combining physical avoidance and acoustic interference. In privacy mode, the system first utilizes the directional characteristics of the loudspeaker to align the sidelobe with the greatest sensitivity attenuation with the non-target area to reduce direct sound energy. Subsequently, the auxiliary loudspeaker is activated and emits anti-phase sound waves according to the interference cancellation equation. This synergistic mechanism of physical attenuation and active cancellation reduces the computational load and error of relying solely on algorithms for open space noise reduction, creating a quiet zone with lower sound pressure levels in non-target areas. Attached Figure Description

[0033] Figure 1 is a hardware architecture diagram of an adjustable pointing angle vehicle speaker provided by an embodiment of the present invention.

[0034] Figure 2 is a schematic diagram of the structure of the electric lifting and rotating speaker unit provided in an embodiment of the present invention.

[0035] Figure 3 is a flowchart of a control method for an adjustable pointing angle vehicle speaker provided by an embodiment of the present invention.

[0036] Figure 4 is a flowchart of acoustic parameter coupling calculation provided in an embodiment of the present invention.

[0037] Among them, 100 is the main control unit; 200 is the in-vehicle microphone array; 300 is the electric lifting and rotating speaker unit; 400 is the auxiliary speaker unit; and 500 is the adaptive digital signal processing power amplifier. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Please refer to Figures 1 and 2. This embodiment of the invention provides an adjustable pointing angle vehicle speaker, including a main control unit 100, an in-vehicle microphone array 200 electrically connected to the main control unit 100, an electrically lifting and rotating speaker unit 300, an auxiliary speaker unit 400, and an adaptive digital signal processing power amplifier 500.

[0040] The main control unit 100 serves as the core computing and control hub. It receives digital signals collected by the in-vehicle microphone array 200 via the bus and sends angle control commands to the electric lifting and rotating speaker unit 300 and parameter configuration commands to the adaptive digital signal processing power amplifier 500. The audio stream processed by the adaptive digital signal processing power amplifier 500 is output to the electric lifting and rotating speaker unit 300 and the auxiliary speaker unit 400.

[0041] The in-vehicle microphone array 200 consists of multiple omnidirectional microphone units distributed in different locations inside the vehicle cabin. The in-vehicle microphone array 200 is configured to acquire analog speech signals in the in-vehicle sound field environment in real time and convert the analog speech signals into multi-channel digital signals.

[0042] The in-vehicle microphone array 200 transmits digital signals to the main control unit 100 via a digital audio interface (such as an I2S interface or an A2B bus), providing raw data input for subsequent instruction semantic parsing and sound source localization calculation.

[0043] The main control unit 100 includes a processor, a memory, and a communication interface. The memory stores computer program instructions, three-dimensional geometric model data of the vehicle interior, and speaker directivity data. The processor is configured to execute the program instructions in the memory to implement control logic.

[0044] Based on the received digital signal, semantic analysis is performed to determine the instruction intent, and the time difference of arrival algorithm and sound source localization equation are executed to calculate the head center coordinates of the occupant who made the sound.

[0045] Simultaneously, the physical path is planned based on the instruction intent and coordinate data, and the audio parameters are calculated according to the dynamic delay compensation equation or interference cancellation equation, ultimately generating angle control instructions and parameter configuration instructions.

[0046] The main control unit 100 interacts with other components via a communication interface (such as CAN bus or vehicle Ethernet).

[0047] The main control unit 100 is configured to perform semantic analysis based on the received digital signal to determine the instruction intent, and to execute the time difference of arrival algorithm and the sound source localization equation to solve the head center coordinates of the occupant.

[0048] The main control unit 100 is also configured to plan the physical path according to the instruction intent and coordinate data, and calculate the audio parameters according to the dynamic delay compensation equation or interference cancellation equation, and finally generate angle control instructions and parameter configuration instructions.

[0049] The motorized lift-and-rotate speaker unit 300 adopts a motorized speaker assembly product with multi-axis mechanical adjustment function known in the prior art (such as a commercially available motorized lift-and-rotate tweeter unit). Structurally, it integrates a high-directivity speaker unit, a lift-and-rotate drive mechanism, and a motor control circuit.

[0050] The electrically operated lifting and rotating speaker unit 300 is equipped with a control signal input interface and an audio signal input interface. The control signal input interface is connected to the main control unit 100 to receive angle control commands.

[0051] The motor control circuit inside the electric lifting and rotating speaker unit 300 drives the lifting and rotating drive mechanism according to the angle control command, so that the high directivity speaker unit performs the actions of raising and lowering, and rotates around the vertical axis to change the azimuth angle, and rotates around the horizontal axis to change the pitch angle.

[0052] Preferably, the electric lifting and rotating speaker unit 300 can also feed back the current step position or angle status information to the main control unit 100 so that the system can monitor the motion process.

[0053] The audio signal input interface is connected to the adaptive digital signal processing power amplifier 500 to receive the processed audio stream and convert it into sound waves.

[0054] The auxiliary speaker unit 400 is installed in a fixed location within the vehicle cabin, such as inside the door trim panel or seat headrest, and is electrically connected to the adaptive digital signal processing power amplifier 500. In interference noise cancellation mode, the auxiliary speaker unit 400 responds to the inverted audio signal output by the adaptive digital signal processing power amplifier 500 by emitting sound waves to cancel out the sound energy in non-target listening areas.

[0055] The adaptive digital signal processing power amplifier 500 is an audio processing unit that integrates a digital signal processing chip and a power amplification circuit, and is connected to the main control unit 100 and the vehicle audio source.

[0056] The adaptive digital signal processing power amplifier 500 is configured to receive coupling parameters from the master control unit 100, including dynamic delay, gain coefficient and additional phase delay.

[0057] The adaptive digital signal processing power amplifier 500 integrates a programmable delay, a parametric equalizer, and a phase controller to process the original audio stream in real time using the aforementioned coupling parameters, and then amplifies and outputs the processed audio signal to the electrically operated lifting and rotating speaker unit 300 and the auxiliary speaker unit 400.

[0058] Referring to Figures 1 and 3, this embodiment of the invention also provides a control method for an adjustable pointing angle vehicle speaker. This method, based on the aforementioned vehicle speaker, includes the following steps:

[0059] Step S1: The in-vehicle microphone array 200 collects voice signals in the in-vehicle sound field environment in real time and converts the voice signals into multi-channel digital signals, which are then input to the main control unit 100. The main control unit 100 performs semantic analysis on the digital signals, identifies the user's command intent, and determines whether the current requirement is high-fidelity mode, surround mode, or privacy mode.

[0060] In step S2, the main control unit 100 processes the digital signal using a time-of-arrival algorithm to calculate the head center coordinates of the occupant. The main control unit 100 establishes a three-dimensional Cartesian coordinate system with the vehicle chassis center as the origin and calculates the head center coordinates of the occupant based on the sound source localization equation. The sound source localization equation is as follows:

[0061] ;

[0062] In the formula: Speed ​​of sound; For microphone The timestamp of the received sound source signal; For microphone The timestamp of the received sound source signal; Let be the location vector of the sound source to be determined; For microphone Position vector; For microphone Position vector; This is the Euclidean norm operator.

[0063] If the instruction in step S1 is intended for privacy mode, the main control unit 100 also determines the head center coordinates of the non-target listening area based on the vehicle seat layout data.

[0064] In step S3, the main control unit 100 plans the physical path of sound wave propagation and calculates the required physical pointing angle of the electric lifting and rotating speaker unit 300 based on the instruction intent and the coordinate data calculated in step S2.

[0065] When the instruction is intended for high-fidelity mode, the azimuth and pitch angles that align the main lobe of the acoustic axis with the occupant are calculated.

[0066] When the instruction is intended for surround mode, the angle at which the acoustic axis points to the specular reflection point on the reflecting surface is calculated based on the virtual source method.

[0067] When the instruction is intended for privacy mode, the angle at which the sidelobe that maximizes sensitivity attenuation is aligned with the non-target listening area is calculated.

[0068] The main control unit 100 generates angle control commands based on the calculation results.

[0069] In step S4, the main control unit 100 calculates the audio parameters required by the adaptive digital signal processing power amplifier 500 based on the physical path planning results. For the high-fidelity mode, the main control unit 100 calculates the dynamic delay amount based on the dynamic delay compensation equation. The dynamic delay compensation equation is as follows:

[0070] ;

[0071] In the formula: This is the dynamic delay amount; The system's preset reference time; The target occupant position vector; The vector representing the center position of the speaker; Speed ​​of sound; This is the Euclidean norm operator.

[0072] For privacy mode, the main control unit 100 calculates the required gain coefficient and additional phase delay for the auxiliary speaker unit 400 based on the interference cancellation equation. The interference cancellation equation is as follows:

[0073] ;

[0074] In the formula: The main sound pressure level; is the base of the natural logarithm; The imaginary unit; Angular frequency; It is a continuous-time variable; Main phase; This is the gain coefficient; To assist in the measurement of sound pressure amplitude; For auxiliary phase; This is to add a phase delay.

[0075] In step S5, the main control unit 100 sends the angle control command to the electric lifting and rotating speaker unit 300 to drive it to perform mechanical actions; at the same time, it sends the audio parameters to the adaptive digital signal processing power amplifier 500.

[0076] During the transition period of the electric lifting and rotating speaker unit 300, the adaptive digital signal processing power amplifier 500 uses a linear interpolation algorithm to smoothly transition the current audio parameters to the target parameters, ensuring that the physical position of the electric lifting and rotating speaker unit 300 matches the phase and frequency response characteristics of the audio signal in real time, and completing the dynamic reconstruction of the in-vehicle sound field.

[0077] Step S1 is primarily used to complete the physical acquisition of acoustic data and the logical parsing of command intent, providing input for subsequent acoustic path planning. Step S1 specifically includes the following sub-steps:

[0078] In step S11, the in-vehicle microphone array 200 performs acoustic-to-electrical conversion and analog-to-digital conversion. Multiple omnidirectional microphones in the in-vehicle microphone array 200 sense changes in sound pressure in the in-vehicle sound field environment in real time, converting physical sound waves into analog electrical signals. The analog-to-digital converter (ADC) integrated within the in-vehicle microphone array 200 discretizes the analog electrical signals at a preset sampling rate (e.g., 44.1kHz or 48kHz) and quantization precision (e.g., 16bit or 24bit), generating a multi-channel digital signal containing both time-domain and frequency-domain information.

[0079] In step S12, the main control unit 100 acquires digital signals. The main control unit 100 receives multi-channel digital signals from the in-vehicle microphone array 200 through a digital audio bus interface (e.g., an A2B bus or an I2S interface). For the transmission of digital signals, those skilled in the art can use time-division multiplexing (TDM) technology to transmit multiple microphone data in parallel on a single bus. The specific communication protocol is well-known in the art and will not be elaborated here.

[0080] In step S13, the main control unit 100 performs semantic analysis to determine the instruction intent. The main control unit 100 preprocesses the received digital signal, including echo cancellation (AEC) and background noise suppression (ANS), to extract clean speech feature vectors. The main control unit 100 matches the extracted speech feature vectors with a pre-stored instruction keyword feature library in memory. When a match is successful, the main control unit 100 generates the corresponding instruction intent (denoted as...). ).

[0081] In this embodiment, the instructions are intended to It includes three modes: High Fidelity Mode, Surround Mode, and Privacy Mode.

[0082] High-fidelity mode corresponds to voice commands issued by users, such as "driver's sound effect" or "activate VIP mode", which pursue a direct sound experience.

[0083] The surround mode corresponds to voice commands issued by the user, such as "full car surround" or "cinema mode," which aim to create a sense of spatial immersion.

[0084] Privacy mode corresponds to voice commands issued by users, such as "private call" or "turn on private mode," which aim to isolate the local sound field.

[0085] The main control unit 100 will recognize the instruction intent The data is temporarily stored in a register and used as the basis for logical branch judgment in the physical path planning of the subsequent step S3. At the same time, the main control unit 100 retains the original multi-channel digital signal without semantic processing as the input data for the arrival time difference calculation in the subsequent step S2.

[0086] Step S2 is primarily used to accurately calculate the spatial position of the occupant based on acoustic data, providing the geometric parameter basis for the subsequent physical path planning of the main control unit 100. Step S2 specifically includes the following sub-steps:

[0087] In step S21, the main control unit 100 establishes a three-dimensional spatial coordinate system inside the vehicle and reads the microphone array parameters. The main control unit 100 uses the center point of the vehicle chassis as the origin. A three-dimensional Cartesian coordinate system is established. The known fixed position coordinates of each omnidirectional microphone unit in the in-vehicle microphone array 200 in the three-dimensional Cartesian coordinate system are read from the internal memory.

[0088] The index number for the first microphone is denoted as... Its position vector is denoted as The index number for the second microphone is denoted as... Its position vector is denoted as These positional parameters are fixed constants pre-set in memory during the vehicle's factory calibration phase.

[0089] In step S22, the main control unit 100 calculates the time difference of arrival using a generalized cross-correlation algorithm. The main control unit 100 selects any two digital signals (e.g., microphone signals) from the in-vehicle microphone array 200. With microphone The signals are cross-correlated to each other to extract the time delay estimate between the two signals.

[0090] The main control unit 100 determines the arrival time of the sound source signal at the microphone by finding the peak value of the cross-correlation function. timestamp With the arrival microphone timestamp The difference between them (i.e.) Regarding the specific implementation logic of the cross-correlation algorithm and the selection of the window function, those skilled in the art can use conventional techniques such as PHAT weighting, which are well-known techniques in this field and will not be elaborated here.

[0091] In step S23, the main control unit 100 calculates the head center coordinates of the occupant based on the sound source localization equation. The main control unit 100 substitutes the position vector parameters obtained in step S21 and the time difference parameters obtained in step S22 into the sound source localization equation.

[0092] This equation establishes an equivalence between the sound wave propagation time difference and the spatial geometric distance difference. The main control unit 100 iteratively solves this system of equations using nonlinear least squares or other numerical optimization algorithms to calculate the sound source location vector. The sound source localization equation is as follows:

[0093] ;

[0094] In the formula: The speed of sound represents the speed at which sound waves propagate in the air medium inside the vehicle. This value can be dynamically corrected based on data from the vehicle's temperature sensor or a standard value can be used. For microphone The timestamp of the received sound source signal; For microphone The timestamp of the received sound source signal; Let be the location vector of the sound source to be determined, i.e., the spatial coordinates of the center of the head of the occupant emitting the sound; For microphone The position vector represents its known coordinates in the vehicle's in-vehicle coordinate system; For microphone The position vector represents its known coordinates in the vehicle's in-vehicle coordinate system; The Euclidean norm operator is used to calculate the straight-line distance between two vector points.

[0095] In step S24, the main control unit 100 outputs the target occupant position vector and determines the coordinates of non-target areas. The main control unit 100 then calculates the sound source position vector obtained in step S23. Marked as target occupant position vector If the instruction intent determined in step S1 is privacy mode, the main control unit 100 needs to further determine the non-target listening area that needs to be isolated from the sound field.

[0096] The main control unit 100 retrieves vehicle seat layout data from the memory and, based on the target occupant position vector... Find the preset head center coordinates of the seat area (e.g., driver's seat) and adjacent seat areas (e.g., passenger seat), and mark these coordinates as the head center coordinates of the non-target hearing area. Ultimately, the main control unit 100 will... and It is transmitted outward as an output parameter.

[0097] Step S3 is mainly used to map the acoustic target position to the physical motion parameters of the actuator, thereby realizing path planning based on the acoustic propagation mechanism. Step S3 specifically includes the following sub-steps:

[0098] Step S31: The main control unit 100 reads the initial state parameters of the electrically lifting and rotating speaker unit 300. The main control unit 100 reads the installation center coordinates of the electrically lifting and rotating speaker unit 300 in the three-dimensional spatial coordinate system inside the vehicle from the memory, and records them as the speaker center position vector. .

[0099] At the same time, the main control unit 100 reads the directivity data of the loudspeaker, which describes the sound pressure level sensitivity distribution characteristics of the loudspeaker at different radiation angles, and is used to subsequently determine the relative angular relationship between the main lobe and the side lobes.

[0100] Step S32: When the instruction intent is high-fidelity mode, the main control unit 100 performs physical path planning under the direct sound mode. The main control unit 100 uses spatial vector algebra to calculate the vector from the speaker center position. Pointing to the target occupant position vector The direction vector.

[0101] The main control unit 100 converts the direction vector into spherical coordinate parameters with the rotation axis of the electrically lifting and rotating speaker unit 300 as the reference frame, and calculates the target azimuth and pitch angles. Based on this, the main control unit 100 generates angle control commands to drive the electrically lifting and rotating speaker unit 300 to rotate, so that the central axis of its main lobe coincides with the direction vector, thereby ensuring that high-frequency sound waves radiate directly to the ears of the occupant via the shortest straight path, achieving a zero off-axis response auditory effect.

[0102] Step S33: When the instruction intent is surround mode, the main control unit 100 performs physical path planning under the reflected sound mode. The main control unit 100 calls the pre-stored in-vehicle three-dimensional geometric model to identify the hard acoustic reflective surface (such as side window glass or windshield) that is closest to the electrically lifting and rotating speaker unit 300 and has high reflectivity.

[0103] The main control unit 100 uses the Image Source Method principle to calculate the target occupant position vector. Coordinates of the mirrored imaginary point of the rigid acoustic reflector.

[0104] The main control unit 100 calculates the value of the speaker center position vector. An incident vector pointing to the mirror virtual point is used to generate an angle control command. The electrically operated lifting and rotating speaker unit 300 responds to this command by rotating away from the occupant, pointing its sound axis to the mirror reflection point on the rigid acoustic reflector surface, thereby expanding the spatial width of the sound field through interface reflection.

[0105] In step S34, when the instruction intent is privacy mode, the main control unit 100 executes physical path planning under the interference noise reduction mode. The main control unit 100 executes an avoidance rotation strategy aimed at minimizing the direct sound energy in non-target listening areas.

[0106] Based on the read speaker directivity data, the main control unit 100 retrieves the sidelobe angle or null angle with the largest sensitivity attenuation amplitude. The main control unit 100 then calculates how to align this sidelobe angle or null angle with the center coordinates of the head in the non-target listening area. The required physical rotation parameters are used to generate angle control commands in the main control unit 100, which drive the electric lifting and rotating speaker unit 300 to deviate its main energy zone of sound radiation from the non-target listening area, thus creating favorable physical sound field conditions for subsequent sound wave interference cancellation.

[0107] For the specific mechanical drive implementation of the electric lifting and rotating speaker unit 300, those skilled in the art can use a stepper motor in conjunction with a worm gear mechanism or a direct drive servo motor for control, which is a well-known technology in the field and will not be described in detail here.

[0108] Referring to Figure 4, step S4 is mainly used to establish a quantitative mapping relationship between the physical space state and the digital signal processing parameters, realizing the adaptive coupling calculation of acoustic parameters. Step S4 specifically includes the following sub-steps:

[0109] Step S41: When the instruction intent determined in step S1 is high-fidelity mode, the main control unit 100 performs parameter coupling calculation under direct acoustic mode.

[0110] Because the physical position change of the electrically operated lifting and rotating speaker unit 300 alters the sound wave transmission distance, the main control unit 100 calculates the required dynamic delay for each channel of the electrically operated lifting and rotating speaker unit 300 based on a dynamic delay compensation equation to ensure the interaural time difference (ITD) and phase consistency of the sound waves reaching the ears of the occupant. The dynamic delay compensation equation is as follows:

[0111] ;

[0112] In the formula: This is the dynamic delay amount, representing the time delay compensation value that the adaptive digital signal processing power amplifier 500 needs to apply. The preset reference time for the system represents the standard propagation time from the reference acoustic center to the human ear; The target occupant position vector is the determined head coordinates of the occupant who emitted the sound, calculated from the sound source localization equation. The vector represents the center position of the loudspeaker, indicating the coordinates of the electrically operated lifting and rotating speaker unit 300 at its current position. Speed ​​of sound; This is the Euclidean norm operator.

[0113] In step S42, when the instruction intent is surround mode, the main control unit 100 performs parameter coupling calculations under the reflected sound mode. Given that the reflection process of sound waves on a rigid acoustic reflector involves frequency-dependent absorption and scattering losses, the main control unit 100 generates parameter configuration instructions and calls the preset diffusion field equalizer within the adaptive digital signal processing power amplifier 500.

[0114] The diffuse field equalizer is configured to boost the gain of high-frequency bands above 2kHz in the audio stream, compensate for energy attenuation in reflection paths, and apply a decorrelation filter to increase the perceived spatial width of the sound.

[0115] Step S43: When the instruction intent is privacy mode, the main control unit 100 performs parameter coupling calculations under the interference noise reduction mode. The main control unit 100 activates the auxiliary speaker unit 400 located near the non-target listening area, and uses the principle of sound wave interference to calculate the head center coordinates in the non-target listening area. A quiet zone was constructed there.

[0116] The main control unit 100 calculates the required gain coefficient and additional phase delay of the auxiliary speaker unit 400 relative to the original signal based on the interference cancellation equation. The interference cancellation equation is as follows:

[0117] ;

[0118] In the formula: The main sound pressure level (MPL) represents the amplitude of the sound waves generated by the electric lifting and rotating speaker unit 300 in the non-target listening area. is the base of the natural logarithm; The imaginary unit; Angular frequency; It is a continuous-time variable; The main phase indicates the initial phase when the sound wave from the electric lifting and rotating speaker unit 300 reaches the non-target listening area. The gain coefficient represents the amplitude adjustment ratio of the output signal of the auxiliary speaker unit 400 relative to the original signal. The auxiliary sound pressure amplitude represents the original sound wave amplitude generated by the auxiliary speaker unit 400 in the non-target listening area; The auxiliary phase indicates the initial phase when the sound wave from the auxiliary speaker unit 400 reaches the non-target listening area; The additional phase delay represents the amount of phase offset adjustment artificially applied by the adaptive digital signal processing power amplifier 500.

[0119] The main control unit 100 analyzes the complex equation and outputs a determined gain coefficient. and additional phase delay .

[0120] Step S5 is primarily used to coordinate the synchronized actions of the physical actuators and the signal processing unit, ensuring a smooth transition of the system from the current sound field state to the target sound field state. Step S5 specifically includes the following sub-steps:

[0121] In step S51, the main control unit 100 performs instruction distribution and synchronization triggering. The main control unit 100 sends the angle control command generated in step S3 to the control signal input interface of the electric lifting and rotating speaker unit 300 via the vehicle control bus (e.g., LIN bus or CAN bus).

[0122] Synchronously, the main control unit 100 transmits the coupling parameters (dynamic delay) calculated in step S4 through a control data channel (e.g., an I2C interface or an SPI interface). Gain coefficient and additional phase delay The commands are encapsulated as parameter configuration instructions and sent to the adaptive digital signal processing power amplifier 500. The main control unit 100 ensures that the timing of the two sets of instructions is synchronized to trigger the coordinated start of physical action and signal modulation.

[0123] In step S52, the electric lifting and rotating speaker unit 300 performs mechanical attitude adjustment. The motor control circuit inside the electric lifting and rotating speaker unit 300 responds to the received angle control command and calculates the step difference between the current position and the target position.

[0124] The motor control circuit drives the lifting and rotating drive mechanism, causing the highly directional speaker unit to move according to a preset angular velocity and acceleration curve. This movement process includes raising the speaker unit from its retracted state, rotating it around the vertical axis to the target azimuth angle, and rotating it around the horizontal axis to the target pitch angle.

[0125] In step S53, the adaptive digital signal processing power amplifier 500 performs a linear interpolation transition of the audio parameters. During the transition time when the electrically operated lifting and rotating speaker unit 300 performs mechanical rotation, the adaptive digital signal processing power amplifier 500 does not immediately switch the audio parameters to the target value, but instead initiates the linear interpolation algorithm.

[0126] Specifically, the system obtains the current raw audio parameters and the target audio parameters issued by the main control unit 100, and calculates a series of intermediate transition parameters based on the preset interpolation step size or time interval.

[0127] Subsequently, these intermediate transition parameters are used to update the register values ​​of the internal delay unit, equalizer, and phase controller frame by frame, so that the phase and frequency response characteristics of the output audio signal change linearly with time. This processing method can effectively eliminate audio pop noise caused by abrupt parameter changes and Doppler distortion caused by rapid phase shifts, ensuring a smooth and continuous listening experience.

[0128] In step S54, the system completes the dynamic reconstruction of the sound field and enters a steady state. When the electrically operated lifting and rotating speaker unit 300 reaches the target physical angle and the parameters of the adaptive digital signal processing power amplifier 500 are updated to the target value, the system enters a steady state.

[0129] At this point, the physical orientation of the electrically operated lifting and rotating speaker unit 300 is precisely matched with the sound wave propagation path, and the phase of the audio signal output by the adaptive digital signal processing power amplifier 500 is precisely matched with the physical transmission distance. In high-fidelity mode, the occupant experiences direct sound with zero off-axis response.

[0130] In surround mode, the in-car sound field gains spatial width through the expansion of the reflective surface; in privacy mode, non-target listening areas gain a quiet zone formed by the combined effect of physical avoidance and interference cancellation.

[0131] In summary, this invention provides an adjustable pointing angle vehicle speaker and its control method. This technical solution overcomes the limitations of traditional vehicle audio systems that rely solely on fixed unit layouts or digital algorithm tuning, and establishes a linkage mechanism that deterministically maps the mechanical degrees of freedom of the speaker to audio signal processing parameters.

[0132] By coordinating the control of the electric lifting and rotating speaker unit and the adaptive digital signal processing power amplifier by the main control unit, this invention achieves real-time matching between the physical acoustic path and the characteristics of the digital signal.

[0133] In the direct sound mode (corresponding to high-fidelity mode), the device uses physical alignment to eliminate high-frequency off-axis attenuation and combines dynamic delay compensation to eliminate phase distortion caused by mechanical displacement, ensuring accurate sound image positioning of the listening position.

[0134] In the reflected sound mode (corresponding to the surround mode), the device uses the hard interface inside the vehicle to construct a virtual source, and with the help of the diffusion field equalization, it expands the spatial width of the sound field, solving the problem of insufficient spatial sense of traditional directional speakers.

[0135] In the interference noise reduction mode (corresponding to privacy mode), the device uses physical avoidance to reduce the direct sound energy in non-target areas, and combines the phase interference principle to construct a silent zone in a specific area, achieving a physical-level sound field isolation effect that is difficult to achieve by relying solely on digital algorithms.

[0136] This invention, through deep coupling between physical actuators and signal processing units, can dynamically reconstruct the in-vehicle sound field environment according to user intent without increasing the number of additional speakers, thereby improving the intelligence level and auditory experience of the in-vehicle audio system.

[0137] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vehicle-mounted speaker with adjustable directional angle, characterized in that, include: The vehicle includes an in-vehicle microphone array for acquiring voice signals and converting them into digital signals; a main control unit for performing semantic analysis on the digital signals to identify command intent, calculating the head center coordinates using a time-of-arrival algorithm, planning a physical path based on the command intent and the head center coordinates, calculating audio parameters, and generating angle control commands and parameter configuration commands; an electrically operated lifting and rotating speaker unit for responding to the angle control commands by performing mechanical actions to adjust the azimuth and pitch angles; an auxiliary speaker unit connected to an adaptive digital signal processing power amplifier; and the adaptive digital signal processing power amplifier for receiving the parameter configuration commands, processing the audio stream in real time based on the audio parameters, and driving the electrically operated lifting and rotating speaker unit and the auxiliary speaker unit.

2. The vehicle-mounted speaker with adjustable pointing angle according to claim 1, characterized in that, The main control unit is also used to construct a mapping relationship between the physical angle of the electric lifting and rotating speaker unit and the audio parameters of the adaptive digital signal processing power amplifier, so as to realize the reconstruction of the in-vehicle acoustic path; the mapping relationship specifically includes: associating the target physical pointing angle of the electric lifting and rotating speaker unit with the time delay, frequency response characteristics or phase parameters of the audio stream, so that the audio parameters can be synchronously adapted to the changed in-vehicle acoustic path during the mechanical movement of the electric lifting and rotating speaker unit.

3. A control method for an adjustable pointing angle vehicle speaker, characterized in that, An adjustable pointing angle vehicle speaker according to any one of claims 1-2 includes the following steps: S1, the main control unit acquires a digital signal collected and converted by an in-vehicle microphone array, and performs semantic analysis on the digital signal to identify the instruction intent; S2, the main control unit processes the digital signal using a time difference of arrival algorithm to calculate the head center coordinates of the occupant; S3, the main control unit calculates the target physical pointing angle of the electrically lifting and rotating speaker unit based on the instruction intent and the head center coordinates, and generates an angle control instruction; S4, the main control unit performs acoustic parameter coupling calculation based on the physical path planning result corresponding to the target physical pointing angle, and calculates audio parameters by identifying the acoustic mode corresponding to the instruction intent and based on the calculation strategy corresponding to the acoustic mode, and generates a parameter configuration instruction; S5, the main control unit simultaneously sends the angle control instruction and the parameter configuration instruction to drive the electrically lifting and rotating speaker unit to perform mechanical actions and control the adaptive digital signal processing power amplifier to process the audio stream based on the audio parameters, respectively.

4. The control method for an adjustable pointing angle vehicle speaker according to claim 3, characterized in that, In step S1, identifying the instruction intent specifically includes: the main control unit performing semantic analysis on the digital signal and identifying and determining whether the instruction intent is a high-fidelity mode, a surround mode, or a privacy mode; wherein, the acoustic modes include direct sound mode, reflected sound mode, and interference noise reduction mode, the high-fidelity mode corresponds to the direct sound mode, the surround mode corresponds to the reflected sound mode, and the privacy mode corresponds to the interference noise reduction mode.

5. The control method for an adjustable pointing angle vehicle speaker according to claim 4, characterized in that, The S2 step specifically includes: the main control unit establishing a three-dimensional Cartesian coordinate system with the center of the vehicle chassis as the origin; the main control unit using the time difference of arrival algorithm to process the digital signal according to the sound source localization equation, and calculating the head center coordinates of the occupant; wherein, the sound source localization equation is used to describe the quantitative relationship between the sound wave propagation time difference and the spatial geometric distance difference.

6. The control method for an adjustable pointing angle vehicle speaker according to claim 4, characterized in that, When the instruction intent is high-fidelity mode, steps S3 and S4 specifically include: in step S3, the main control unit calculates the direction vector from the current center position vector of the electric lifting and rotating speaker unit to the head center coordinate, and generates the angle control instruction to align the main lobe of the sound axis with the head center coordinate; in step S4, the main control unit calculates the audio parameters specifically including: calculating the dynamic delay amount based on the dynamic delay compensation equation.

7. The control method for an adjustable pointing angle vehicle speaker according to claim 5, characterized in that, When the instruction is intended for surround mode, steps S3 and S4 specifically include: In step S3, the main control unit calls the in-vehicle three-dimensional geometric model, uses the virtual source method to calculate the mirror point of the head center coordinates with respect to the nearest hard reflective surface, and generates the angle control instruction that makes the acoustic axis point to the mirror reflection point on the hard reflective surface; In step S4, the main control unit calculates the audio parameters specifically including: generating configuration parameters for controlling the adaptive digital signal processing power amplifier to perform diffusion field equalization processing, the configuration parameters being used to increase the gain of the high-frequency band to compensate for reflection loss.

8. The control method for an adjustable pointing angle vehicle speaker according to claim 7, characterized in that, When the instruction is intended for privacy mode, step S3 specifically includes: the main control unit determines the head center coordinates of the non-target listening area based on the vehicle seat layout data; the main control unit calculates the side lobe angle with the greatest sensitivity attenuation based on the directivity data of the electric lifting and rotating speaker unit, and generates the angle control instruction that aligns the side lobe angle with the head center coordinates of the non-target listening area based on the head center coordinates of the non-target listening area; wherein, the vehicle seat layout data, the in-vehicle three-dimensional geometric model, and the three-dimensional Cartesian coordinate system are preset and stored in the memory of the main control unit based on the vehicle factory calibration parameters.

9. The control method for an adjustable pointing angle vehicle speaker according to claim 8, characterized in that, When the instruction is intended for privacy mode, step S4 specifically includes: the main control unit activates the auxiliary speaker unit corresponding to the non-target listening area; the main control unit calculates the gain coefficient and additional phase delay required by the auxiliary speaker unit according to the interference cancellation equation, and uses the gain coefficient and additional phase delay as the audio parameters; wherein, the interference cancellation equation is used to calculate the signal parameters required to form a silent zone in the non-target listening area.

10. The control method for an adjustable pointing angle vehicle speaker according to claim 3, characterized in that, The S5 step further includes: during the transition period when the electric lifting and rotating speaker unit performs mechanical action, the adaptive digital signal processing power amplifier uses a linear interpolation algorithm to smoothly transition the current audio parameters to the target audio parameters.

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