Active noise reduction device and active noise reduction method for air outlet of cab of commercial vehicle

Abstract

The invention provides an active noise reduction device and an active noise reduction method for an air outlet of a commercial vehicle cab, belongs to the technical field of noise reduction of commercial vehicle cabs, and particularly aims at noise reduction of the commercial vehicle cabs, human image recognition systems are installed at the positions of a main driver, a co-driver and a sleeping berth to judge the existence conditions of drivers and passengers, and active noise reduction is started and stopped in combination with the state of an air conditioner. An active noise reduction device containing various parts is installed at an air outlet of the air conditioner, and the position and angle of an error microphone are adjusted after information of the air outlet and the like is obtained. The adjusted error microphone collects noise signals and transmits the noise signals to the controller, the controller controls the headrest loudspeaker to generate counteracting sound according to the positions of the driver and passengers, and part of natural wind sound is reserved. The driver and passengers are recognized, the noise reduction system is controlled to be started and stopped, and energy consumption is reduced. The noise reduction device can adapt to air outlets of different vehicle types and air outlet parameter changes, noise is collected, noise reduction is achieved, natural wind sound is reserved, the comfort degree is improved, and the individual noise reduction requirement of passengers is met.

Description

Technical Field

[0001] This invention belongs to the field of noise reduction technology for commercial vehicle cabs, specifically relating to an active noise reduction device and method for the air vents of commercial vehicle cabs. Background Technology

[0002] During operation, commercial vehicles often experience persistently high levels of noise in the cab. This is especially true when the air conditioning system is on, as the noise from turbulence generated by airflow through the ducts and vents, the electromagnetic noise from the fan motor, and the low-frequency rumbling caused by fluctuations in the engine cooling fan speed all combine to significantly worsen the driving and riding environment.

[0003] Active Noise Control (ANC) technology is gradually being applied to the passenger vehicle field. Its principle is to collect noise signals through error microphones, generate anti-phase sound waves through the controller, and cancel the target noise through speakers.

[0004] In the process of active noise cancellation, related technologies are generally used in conjunction with microphones. These microphones are fixed in the driver's cab. Because the microphone is fixed in one position, it cannot move with the adjustment of the air conditioning vent angle. Commercial vehicle occupants frequently adjust the vent angle as needed. The fixed microphone will then deviate from the area of ​​strongest noise due to the change in airflow direction, resulting in inaccurate noise signal collection. This leads to a mismatch between the canceled sound and the actual noise, reducing the noise cancellation effect, or even causing noise cancellation to fail.

[0005] Active noise cancellation technologies can also easily lead to over-cancellation, completely canceling out natural sounds such as wind noise in the driver's cabin and creating a closed, silent environment. Prolonged exposure to a completely silent environment can cause a noticeable feeling of confinement and oppression, affecting auditory comfort and potentially leading to fatigue, inattention, and other problems for drivers and passengers, thus compromising driving safety. Summary of the Invention

[0006] This invention provides an active noise reduction device for the air vents of commercial vehicle cabs. An error microphone sensor is integrated into the air vent, making it applicable to air vents with different duct structures in commercial vehicle cabs. The active noise reduction device is unaffected by changes in the airflow angle, air volume, and engine fan speed of the air conditioning vent, ensuring stable active noise reduction performance under various operating conditions.

[0007] The active noise reduction device for the air vents of the commercial vehicle cab includes: an outer frame, with an error microphone holder installed in the middle of the outer frame; The inner wall of the outer frame is equipped with slide rails; A lead screw is fixed to the error microphone holder; one end of the lead screw is slidably connected to the slide rail; the other end of the lead screw is connected to a motor. The error microphone holder is set in the middle of the outer frame by a lead screw; The error microphone holder has a mounting hole in the middle.

[0008] Preferably, an error microphone locking mechanism is provided on the inner wall of the mounting hole.

[0009] Preferably, bolt holes are provided at the four ends of the outer frame.

[0010] This invention also provides an active noise reduction method for the air vents of a commercial vehicle cab, the method comprising: S101: Install facial recognition systems in the driver's cab, passenger's cab, and driver and passenger's sleeper berths of the commercial vehicle cab. By collecting images of the cab and combining them with body temperature characteristics, identify whether there are drivers or passengers in the cab. S102: Based on the obtained occupant identification results and the air conditioning status, if there are occupants and the air conditioning is on, the active noise cancellation system will be activated. S103: An active noise reduction device is installed at the air conditioning vent in the cab of a commercial vehicle. The active noise reduction device is connected and fixed to the interior panel through bolt holes. The air conditioning vent blade angle, air volume and engine fan speed information are obtained in real time through CAN. S104: Based on the acquired information of air conditioner vent blade angle, air volume and engine fan speed, the motor of the active noise reduction device drives the lead screw to move along the slide rail, and the four-point locking device applies different forces to different points, so that the error microphone moves to the target position and is adjusted to a posture that matches the vent angle. S105: The noise signal at the target location is collected through the adjusted error microphone and transmitted to the active noise cancellation controller; S106: The active noise cancellation controller controls the headrest speakers at the corresponding positions to emit a canceling sound with the same amplitude but opposite direction as the noise signal transmitted in step S105, based on the identified driver and passenger position information, and retains 20-30dB of natural wind sound through psychoacoustic algorithms.

[0011] Preferably, S101 includes the following steps: Multispectral cameras are embedded in the top and side walls of the driver's cab, passenger's cab, and sleeper area. The cameras use visible light and near-infrared dual-channel sensors to capture the contour information of the driver and passengers. An infrared thermal imaging probe is installed below each camera, with the probe's coverage overlapping the camera's field of view, to acquire real-time surface temperature distribution data of the target area. The detection data from the camera and infrared thermal imaging probe are transmitted to the controller via the CAN bus. The controller processes the visual features and thermal signals synchronously, and based on the YOLOv5 architecture neural network model, the input layer receives dual-channel data streams, and the output layer generates a binary judgment result of the presence status of the driver and passengers.

[0012] Preferably, S102 includes the following steps: Connect the output of the facial recognition system to the input of the logic judgment module so that the driver and passenger information identified by the facial recognition system can be transmitted to the logic judgment module. An air conditioning status detection device is installed on a commercial vehicle. The output of the air conditioning status detection device is connected to another input of the logic judgment module, so that the air conditioning on status information detected by the air conditioning status detection device is transmitted to the logic judgment module. In the logic judgment module, a judgment rule is set. When the system receives information about the presence of drivers and passengers from the facial recognition system and information about the air conditioning being turned on from the air conditioning status detection device, a start signal is output. Connect the output of the logic judgment module to the control input of the active noise cancellation system. When the logic judgment module outputs a start signal, the active noise cancellation system receives the signal and starts.

[0013] Preferably, S103 includes the following steps: Measure the inner length, width and duct depth of the air outlet of the commercial vehicle's air conditioning system, adjust the nested expansion joint of the outer frame of the active noise reduction device, and lock the frame size after turning the locking knob on the side of the frame to match the inner edge size of the air outlet and the depth to match the duct depth. Push the adjusted outer frame into the air duct of the air conditioning vent, so that the front end of the frame is flush with the air vent decorative panel. Mark the drilling points on the corresponding position of the interior panel through the bolt holes of the device, and then take out the active noise reduction device. Select a twist drill bit that matches the bolt diameter of the active noise reduction device, align it with the marked position and drill a hole in the interior panel, then tap the hole with a matching tap. Align the air outlet duct of the outer frame with the bolt holes of the device and the tapping holes of the interior panel, and tighten the bolts twice to complete the device fixation; insert the slide rail into the slot of the inner wall of the frame and fix it, embed the screw into the guide groove of the slide rail, and fix the motor in the reserved position of the end plate of the frame through the flange.

[0014] Preferably, S104 includes the following steps: S1041: The active noise reduction controller obtains the target spatial coordinates (X, Y) and target deflection angle α calculated based on the current air outlet blade angle, air volume and engine fan speed from the pre-trained neural network model; The target spatial coordinates define the planar position that the error microphone should reach in the plane of the device slide rail, and the angle α defines the angle relationship between the microphone's main pickup axis and the main airflow axis of the air outlet. S1042: The controller compares the target coordinates (X, Y) with the current position coordinates fed back by the displacement sensor integrated on the error microphone holder and generates a position deviation signal; S1043: While the position moves, the controller acquires the target deflection angle α; the four-point locking device consists of four electric push rods, which are arranged symmetrically in a cross shape around the error microphone holder; The controller calculates the torque that needs to be applied to the microphone body based on the target deflection angle α, and decomposes it into linear forces F1 to F4 that need to be applied at four points. S1044: Integrates a MEMS tilt sensor on the error microphone holder for real-time measurement of the microphone barrel's current pitch and roll angles.

[0015] Preferably, S106 includes the following steps: The active noise cancellation controller receives the position signal of the driver and passengers and the noise simulation signal collected by the error microphone, and determines the final noise cancellation area position signal according to the priority of manual control commands and automatic recognition commands. The active noise cancellation controller conditions and performs analog-to-digital conversion on the noise analog signal, and generates an initial cancellation digital signal through a phase inversion algorithm; The active noise cancellation controller activates the corresponding headrest speaker channel stored in advance based on the noise cancellation area location signal, and adjusts the output power of the initial cancellation digital signal based on the speaker parameters. The active noise cancellation controller converts the adjusted cancellation digital signal into an analog signal and amplifies it before outputting it to the headrest speaker. It also collects the noise-cancelled mixed signal through a feedback microphone and adjusts the amplitude and phase of the cancellation signal until the noise reduction effect meets the preset requirements.

[0016] Preferably, S106 further includes the following steps: In the active noise cancellation controller, two processing paths are set up in parallel: the first path is a full-band active noise cancellation processing path, and the second path is a psychoacoustic processing path. Set up a digital mixer to mix the full-band inverted signal processed by the first channel with the attenuated high-frequency retained signal output by the second channel; A manual control panel with a touch area is installed on the center console of the driver's cab; the manual control panel has five options: automatic mode, driver's mode, passenger's mode, all-vehicle mode and off mode, and each option corresponds to a digital code; the currently selected code on the control panel is transmitted to the active noise cancellation controller in real time; The logic arbitration unit of the active noise cancellation controller is equipped with a dual-input priority judgment module. The dual-input priority judgment module is connected to the manual control panel to transmit command codes, and the dual-input priority judgment module is also connected to the facial recognition system to obtain facial recognition result codes.

[0017] As can be seen from the above technical solutions, the present invention has the following advantages: This invention provides an active noise reduction device and method for commercial vehicle cab air vents, reducing ineffective energy consumption of active noise reduction systems. Through the linkage control of facial recognition and air conditioning status, the system only activates when there are passengers and the air conditioning is on. By acquiring real-time air vent blade angles, airflow, and engine fan speed, the error microphone is precisely moved and matched to the air vent angle, ensuring the microphone is always in the optimal position for noise acquisition. This results in a higher degree of matching between canceled sound and noise, and a stable noise reduction effect. The telescopic outer frame of the active noise reduction device can adapt to the air vent sizes of different vehicle models, and is compatible with both manual and automatic noise reduction position selection, catering to the needs of different occupants. Psychoacoustic algorithms accurately retain 20-30dB of natural wind sound, making the auditory environment in the cab more natural and improving comfort during long-distance driving. Multiple signal feedback adjustments reduce the impact of mechanical errors on system operation, ensuring stable operation under complex environments such as vehicle bumps and fluctuating operating conditions. Attached Figure Description

[0018] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying 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.

[0019] Figure 1 A 3D view of an active noise reduction device for the air vents in the cab of a commercial vehicle. Figure 2 Schematic diagram of an active noise reduction device for the air vents in the cab of a commercial vehicle; Figure 3 Flowchart of an active noise reduction method for air vents in the cab of a commercial vehicle; Figure 4 Flowchart of an embodiment of an active noise reduction method for air vents in the cab of a commercial vehicle; Figure 5 This is an example of active noise reduction in the cab of a commercial vehicle. Detailed Implementation

[0020] This invention provides an active noise reduction device for the air vents of commercial vehicle cabs, designed to address the noise problem caused by the coupling effect of the air vent angle, airflow, and engine fan speed when the air conditioning is turned on in commercial vehicles. The device is installed after the air conditioning duct and before the vehicle's air conditioning fan blades, and is bolted to the vehicle's interior trim panel. The device frame is flexible, allowing for size changes through compression or stretching to adapt to the air vents of different vehicle models.

[0021] Optionally, this invention can be implemented based on an active noise cancellation device, a facial recognition system, driver / passenger seats, an infrared thermal imaging probe, an active noise cancellation controller, and related software. Specifically, the above configuration can be a single active noise cancellation system. This system has an onboard database, including a pre-trained and usable deep learning database, which analyzes and identifies the maximum noise point generated by the three-way coupling effect at the air vent. The device's lead screw and slide allow the error microphone holder to move in four directions under the action of a motor, enabling the active noise cancellation system's microphone to accurately capture the maximum noise. The error microphone locking device applies different forces at four points to change the error microphone's acquisition angle with the air vent angle, ensuring that the active noise cancellation system's noise reduction function is not affected by changes in the air vent angle. After the error microphone acquires the noise signal, it transmits it to the active noise cancellation control system. The control system processes the signal and causes the headrest speakers to emit sounds of the same amplitude but opposite direction to cancel out the noise, improving the overall sound quality of the cab.

[0022] This invention also achieves occupant identification by installing facial recognition technology in the driver, passenger, and sleeper berth areas. By judging the occupant's physical characteristics and body temperature (35.5℃-37.5℃), the system determines the location of the occupants in the driver's cab and controls the headrest speakers to operate. When no one is in the driver's cab, the speakers stop working. When an occupant is detected in the driver / passenger seat or a single sleeper berth, the system only activates the headrest speaker on the side with the passenger for noise reduction, effectively saving vehicle energy.

[0023] The active noise reduction device and method for the air vents of commercial vehicle cabs involved in this application will be described in detail below. Specific details such as particular system structures and technologies are presented for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0024] It should be understood that "one or more" as mentioned in this application refers to one, two, or more than two, and "multiple" as mentioned in this application refers to two or more. In the description of this application, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B. "And / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone.

[0025] The statements such as "one embodiment" or "some embodiments" described in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the statements such as "in one embodiment," "in some embodiments," "in other embodiments," and "in still other embodiments" in this application do not necessarily refer to the same embodiment, but rather mean one or more, but not all, embodiments, unless otherwise specifically emphasized.

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0027] Please see Figure 1 and Figure 2 The diagram shows a schematic of an active noise reduction device for the air vents of a commercial vehicle cab in a specific embodiment. The device includes: an outer frame 1, with an error microphone holder 6 located near the center of the outer frame 1; a slide rail 3 located on the inner side wall of the outer frame 1; a lead screw 4 fixed on the error microphone holder 6; one end of the lead screw 4 slidably connected to the slide rail 3; and a motor 5 connected to the other end of the lead screw 4; the error microphone holder 6 is located in the center of the outer frame 1 via the lead screw 4; and a mounting hole 7 is located in the center of the error microphone holder 6.

[0028] In some embodiments, the outer frame 1 is integrally stamped from aluminum alloy and has a rectangular frame structure. The inner sidewall of the frame has two parallel dovetail groove slide rail mounting positions along the length direction. The bottom of the mounting position is provided with evenly distributed threaded holes for fixing the slide rail 3 with hexagonal screws.

[0029] In this embodiment, the outer frame 1 is designed as a nested telescopic structure with a scaled locking knob on the side. Rotating the knob can tighten and fix the nested section through the set screw, so as to achieve fine adjustment of the overall length and width of the frame and adapt to the inner edge size range of the air vent of different car models.

[0030] In one optional embodiment, sliders are provided at corresponding positions on the sidewall of the error microphone holder 6 and the slide rail 3 on the inner side of the outer frame 1. The sliders engage with the dovetail grooves of the slide rail 3 to ensure smooth sliding without jamming. An internally threaded sleeve is welded to the middle of the error microphone holder 6. The internal thread specification of the sleeve matches that of the lead screw 4. After the lead screw 4 passes through the sleeve, one end is connected to the end support of the slide rail 3 through a deep groove ball bearing, and the other end is coaxially connected to the output shaft of the motor 5 through an elastic coupling to ensure the coaxiality of power transmission.

[0031] Motor 5 controls the speed and rotation angle through pulse signals, and motor 5 is fixed on error microphone holder 6.

[0032] In this embodiment, motor 5 starts after receiving a pulse command from the active noise cancellation controller, and its output shaft drives the lead screw 4 to rotate around its own axis via a flexible coupling. Since the lead screw 4 and the internal threaded sleeve on the error microphone holder 6 form a helical transmission pair, the rotational motion of the lead screw 4 is converted into linear motion of the error microphone holder 6 along the slide rail 3. The dovetail groove structure of the slide rail 3 guides and limits the slider of the holder, preventing the holder from shifting or rotating during movement. By controlling the number of pulses from motor 5, the rotation angle of the lead screw 4 can be controlled, thereby controlling the moving distance of the error microphone holder 6, ultimately driving the error microphone mounted on the holder to the preset target position.

[0033] The dovetail groove slide rail, in conjunction with the slider, effectively limits the radial displacement of the fixture, ensuring the positional accuracy of the error microphone during movement. The high precision of the lead screw drive, combined with the pulse control of the stepper motor, allows for position adjustment, meeting the positioning requirements of the noise-maximum point under different operating conditions.

[0034] Optionally, a rubber shock-absorbing pad can be installed at the bottom of the motor to reduce the impact of motor vibration on the device and avoid additional noise interference from vibration affecting the microphone's data acquisition.

[0035] In some embodiments, the error microphone holder 6 has a mounting hole 7 in the middle. The diameter of the mounting hole 7 is larger than the outer diameter of the adapted error microphone, leaving an assembly gap to facilitate the installation and removal of the microphone.

[0036] The inner wall of the mounting hole 7 has four mounting slots evenly distributed along the circumference. The four mounting slots correspond to the four points of the fixture, namely the top, bottom, left, and right. A miniature elastic pressure claw is embedded in each mounting slot, forming the error microphone locking mechanism 8.

[0037] The elastic clamping claw is made of nitrile rubber and fits snugly against the shell of the error microphone. An adjusting screw is connected to the tail of the clamping claw. The adjusting screw passes through the side wall of the fixture and has an adjusting nut at the end. Rotating the nut can adjust the extension length of the clamping claw, so as to clamp and fix microphones of different diameters, ensuring a firm fixation without damaging the microphone shell.

[0038] Each of the four ends of the outer frame 1 has a circular bolt hole 2. The bolt hole 2 is a countersunk hole structure, with the diameter of the countersunk section being larger than the bolt head, ensuring that the bolt head is fully embedded in the hole and does not protrude from the surface of the outer frame, thus avoiding interference with other components of the air outlet. The axis of the bolt hole 2 is perpendicular to the end face of the outer frame 1, and the four bolt holes are symmetrically distributed in a rectangle, with the center of symmetry coinciding with the geometric center of the outer frame, ensuring uniform force distribution when the device is fixed.

[0039] The locking mechanism at the four points in this embodiment can be adjusted independently to achieve a stable fixation of the microphone. The angle adjustment is completed by applying uneven force to adapt to different air delivery angles of the air outlet, ensuring that the microphone is always aligned with the noise collection direction.

[0040] The following are embodiments of the active noise reduction method for the air vents of commercial vehicle cabs provided in this disclosure. This method and the active noise reduction device for the air vents of commercial vehicle cabs in the above embodiments belong to the same inventive concept. For details not described in detail in the embodiments of the active noise reduction method for the air vents of commercial vehicle cabs, please refer to the embodiments of the active noise reduction device for the air vents of commercial vehicle cabs described above.

[0041] like Figure 3 and Figure 4 As shown, the method includes: S101: Install facial recognition systems in the driver's cab, passenger's cab, and driver and passenger's sleeper berths of the commercial vehicle cab. By collecting images of the cab and combining them with human body temperature characteristics, the system can identify whether there are drivers or passengers in the cab.

[0042] In some embodiments, the driver's area is located in the center above the dashboard, while the passenger's area and the driver and passenger sleeper berths are respectively equipped with human body data acquisition terminals fixed at their respective berths, which can be detected using infrared thermal imaging probes. Optionally, a camera can be used based on the image acquisition module, with the camera's memory pre-stored with an adult human body shape feature template, including the proportional range parameters of the torso and limbs.

[0043] S101 includes the following steps: S1011: Multispectral cameras are embedded in the top and side walls of the driver's cab, passenger's cab, and sleeper area as a facial recognition system. The cameras use visible light and near-infrared dual-channel sensors to capture the contour information of the driver and passengers in a non-contact manner.

[0044] S1012: An infrared thermal imaging probe is installed below each camera. The probe's coverage overlaps with the camera's field of view to acquire real-time surface temperature distribution data of the target area.

[0045] S1013: The detection data of the camera and infrared thermal imaging probe are transmitted to the controller via the CAN bus. The controller processes the visual features and thermal signals synchronously, and based on the YOLOv5 architecture neural network model, the input layer receives dual-channel data streams, and the output layer generates a binary judgment result of the presence status of the driver and passengers.

[0046] In some embodiments, the raw data from the camera and infrared sensor are divided into an 8-bit grayscale matrix inside the FPGA, and the CAN bus interface is configured with the ISO11898-2 standard protocol to ensure real-time synchronization of dual-mode data.

[0047] The YOLOv5 model has undergone pruning to improve inference speed. The backbone network of the neural network has been replaced with a ShuffleNetV2 structure to reduce computational load while maintaining accuracy. The decision tree algorithm uses an improved version of ID3, selecting feature split points based on information gain ratio, and the final output includes a confidence threshold. When visual features conflict with hot data, the algorithm prioritizes hot data as the decision criterion.

[0048] S102: Based on the occupant identification results obtained in step S101, and combined with the air conditioning status, if there are occupants and the air conditioning is on, then active noise cancellation is activated; if there are no occupants or the air conditioning is not on, then the active noise cancellation system is deactivated.

[0049] S102 includes the following steps: S1021: Connect the output of the facial recognition system to the input of the logic judgment module so that the driver and passenger information identified by the facial recognition system is transmitted to the logic judgment module.

[0050] In some embodiments, after the facial recognition system completes the identification of the driver and passengers in the driver's cab, the facial recognition system continuously transmits information such as whether the identified driver and passengers exist to the logic judgment module in the form of electrical signals.

[0051] S1022: An air conditioning status detection device is installed on a commercial vehicle. The output of the air conditioning status detection device is connected to another input of the logic judgment module, so that the air conditioning on status information detected by the air conditioning status detection device is transmitted to the logic judgment module.

[0052] In some embodiments, the air conditioning status detection device is installed in the air conditioning system of a commercial vehicle and can monitor the operating status of the air conditioning in real time. When the air conditioning is turned on, the air conditioning status detection device senses changes in relevant physical quantities, such as current flow and temperature changes. The air conditioning status detection device converts these changes in physical quantities into electrical signals and transmits them to the logic judgment module.

[0053] S1023: Set judgment rules in the logic judgment module. When the presence of driver and passenger information is received from the facial recognition system and the air conditioning is turned on is received from the air conditioning status detection device, output a start signal.

[0054] In some embodiments, the logic judgment module has pre-set judgment rule circuits or program logic. When it simultaneously receives information about the presence of occupants from the facial recognition system and information about the air conditioning being on from the air conditioning status detection device, the internal judgment rule is triggered. Through logic gates in the circuit or conditional statements in the program, a start signal level is output. This allows for an accurate decision on whether to activate the active noise cancellation system based on the actual occupant and air conditioning status, ensuring that operation meets actual needs.

[0055] S1024: Connect the output of the logic judgment module to the control input of the active noise cancellation system. When the logic judgment module outputs a start signal, the active noise cancellation system receives the signal and starts.

[0056] In some embodiments, the control input of the active noise cancellation system is connected to the output of the logic judgment module. When the logic judgment module outputs a start signal, this signal is transmitted to the control input of the active noise cancellation system in the form of an electrical signal through the connection line. The controller of the active noise cancellation system can recognize this start signal and trigger the system to start working, thereby realizing the start control of the active noise cancellation system.

[0057] S103: An active noise reduction device is installed at the air conditioning vent in the cab of a commercial vehicle. The device includes a telescopic outer frame, bolt holes, slide rails, lead screws, motors, error microphone holders, and a four-point locking device. The device is connected and fixed to the interior panel through the bolt holes, and the air conditioning vent blade angle, air volume, and engine fan speed information are obtained in real time via CAN.

[0058] S103 includes the following steps: S1031: Measure the inner length, width and duct depth of the air outlet of the commercial vehicle's air conditioning system, adjust the nested expansion joint of the outer frame of the active noise reduction device, and lock the frame after adjusting the frame size to match the inner edge size of the air outlet and the depth to match the duct depth by rotating the locking knob on the side of the frame.

[0059] In some embodiments, the outer frame of the active noise cancellation device is a three-section nested metal structure, with a graduated locking knob on each side. Rotating the knobs allows the nested sections to extend or retract. During adjustment, the frame length is adjusted to be a certain length longer than the inner edge of the air outlet, the width is adjusted to a certain width, and the depth is exactly the same as the depth of the air duct. After adjustment, tighten the knobs to lock the frame dimensions.

[0060] S1032: Push the adjusted outer frame into the air duct of the air conditioning vent, so that the front end of the frame is flush with the decorative panel of the air vent. Mark the drilling points on the corresponding position of the interior panel through the bolt holes of the device, and then remove the device.

[0061] In some embodiments, push the adjusted outer frame along the air outlet duct until the front end of the frame is completely flush with the plastic decorative panel of the air outlet. Insert the frame into each bolt hole on the device housing and mark a small dot on the corresponding position on the interior panel to clearly mark the position where each bolt should be screwed in. After marking, gently pull the frame out of the duct.

[0062] S1033: Select a twist drill bit that matches the diameter of the bolt rod, align it with the marked point, drill a hole on the interior panel, and then tap the hole with a matching tap.

[0063] In some embodiments, a twist drill bit is used to drill a hole perpendicular to the surface of the interior panel, with the drilling depth exceeding the bolt length by a certain amount. After drilling, a matching tap is mounted on a tap wrench, and the tap is slowly rotated along the drilled hole, retracting a quarter turn after every half turn to remove chips, until the tapping depth is shorter than the bolt length.

[0064] S1034: Align the air outlet duct of the outer frame with the bolt holes of the device and the tapping holes of the interior panel, and tighten the bolts twice to complete the device fixation; insert the slide rail into the slot of the inner wall of the frame and fix it, embed the screw into the guide groove of the slide rail, and fix the motor in the reserved position of the end plate of the frame through the flange.

[0065] In some embodiments, the adjusted outer frame is pushed further into the air outlet duct, aligning the bolt holes of the device with the tapping holes on the interior panel. Take the matching bolts, pass them through the bolt holes of the device, and pre-tighten them with a torque wrench. After confirming that all bolts are threaded, tighten them one by one. Then, insert the slide rail into the groove on the inner wall of the outer frame, secure both ends of the slide rail with retaining springs, place the lead screw into the guide groove of the slide rail, align the motor flange with the pre-drilled hole on the frame end plate, and secure the motor with two screws.

[0066] S104: Based on the air conditioner vent blade angle, air volume and engine fan speed information obtained in step S103, the motor of the active noise reduction device drives the lead screw to move along the slide rail, and the four-point locking device applies different forces to different points, so that the error microphone moves to the target position and is adjusted to a posture that matches the vent angle.

[0067] It should be noted that the lead screw movement is based on the noise propagation path, diffusion range, and intensity characteristics, and is directionally and distance-dependently correlated with the air conditioner vent blade angle, air volume, and engine fan speed. The angle of the air conditioner vent blades is the core directional basis: the horizontal / vertical deflection angle of the blades directly determines the main propagation direction of the airflow. The lead screw needs to drive the error microphone to move along this direction so that it is on the main propagation path of the noise.

[0068] Noise diffusion range related to air volume: The larger the air volume, the larger the diffusion radius of the noise during propagation, and the microphone target position needs to be closer to the center area of ​​the airflow (the distance from the air outlet needs to be adapted to the diffusion radius).

[0069] Engine fan speed matching noise intensity / frequency: The higher the speed, the higher the sound pressure level and dominant frequency of the fan noise. This type of noise is more directional, and the amount of lead screw movement needs to be finely adjusted so that the microphone is at the point of maximum sound pressure distribution at that frequency.

[0070] The target position is calculated based on a pre-calibrated parameter mapping table, such as the correspondence between blade angle and directional offset, the correspondence between air volume and diffusion radius, and the correspondence between rotation speed and position fine adjustment. Specifically, based on the current blade angle, the horizontal and vertical offset components of the main noise propagation direction are obtained by looking up the calibration table. Based on the current air volume, the diffusion radius is obtained from the calibration table, the reference distance from the air outlet is calculated, and it is decomposed into horizontal and vertical components. Based on the current engine fan speed, the position fine-tuning amount is obtained by referring to the calibration table; By superimposing the above components, we obtain the amount of movement of the lead screw in the X and Y directions, which is the coordinate difference between the initial position and the target position.

[0071] Optionally, to control the motion relationship between the lead screw and the motor, the target position requirement of the error microphone is converted into the motor's operating parameters. This is achieved through parameter calculation, motor drive, position feedback, and locking, as detailed below: First, determine the transmission relationship between the lead screw and the motor. In the device, the motor output shaft is rigidly connected to one end of the lead screw through a coupling, and a nut connected to the error microphone holder is fitted on the lead screw.

[0072] When the motor rotates, it drives the lead screw to rotate synchronously. Utilizing the helical transmission characteristics of the lead screw and nut, the rotational motion of the lead screw is converted into linear motion of the nut and microphone holder along the lead screw axis, i.e., movement along the X / Y directions of the slide rail. The corresponding relationship of their motion parameters is as follows: Lead screw movement = Lead screw lead × Number of motor rotations The lead screw is the distance the nut moves along the axis when the lead screw rotates one revolution. This can be calibrated in advance. For example, if the lead screw is set to 5mm, then when the motor rotates one revolution, the microphone holder moves 5mm along the slide rail.

[0073] The specific control method of the lead screw and motor is to first calculate the target movement of the lead screw. The active noise reduction controller first receives information such as the air conditioner vent blade angle, air volume, and engine fan speed. According to the preset calibration mapping table, it calculates the target movement of the error microphone in the X horizontal and Y vertical directions, that is, the distance from the initial position to the target position.

[0074] Convert the target movement of the lead screw into the motor's control parameters: Based on the lead screw lead, calculate the number of revolutions / angles the motor needs to rotate. For example, if the target movement is 10mm and the lead screw lead is 5mm, the motor needs to rotate 2 revolutions. Combined with the direction of the slide rail, determine the direction of motor rotation; forward / reverse rotation corresponds to the forward / backward movement of the retainer along the slide rail.

[0075] The motor drive control device uses a combination of a stepper motor and a driver: the active noise cancellation controller sends parameters such as the number of rotations and direction of rotation to the motor driver via a CAN bus. The driver converts the electrical signals into the motor's operating power, driving the motor to rotate according to the target parameters, which in turn drives the lead screw to rotate, causing the nut and microphone holder to move along the slide rail.

[0076] For position feedback and precise positioning, a miniature photoelectric switch or encoder is installed next to the lead screw / slide rail: When the fixture moves to the target position, the sensor will send a positioning signal to the controller; after receiving the signal, the controller stops the motor and triggers the four-point locking device to apply clamping force to the corresponding point, locking the fixture on the slide rail to prevent displacement caused by vehicle vibration.

[0077] In this embodiment, two orthogonally arranged lead screws are independently controlled by dual lead screws. They can correspond to the X and Y direction slide rails and be matched with independent motors and control links respectively. The X direction motor controls the horizontal movement of the microphone, and the Y direction motor controls the vertical movement of the microphone. The controller will calculate the movement amount in the X and Y directions respectively and send control commands to the corresponding motors independently, so as to achieve accurate positioning of the error microphone in the plane.

[0078] This is combined with the appendix Figure 1 and Figure 2 As shown, the device uses orthogonally arranged lead screws, one each along the X and Y directions of the cross slide rail, with each lead screw corresponding to a drive motor. The motor output shaft is connected to one end of the lead screw via a coupling, and the motor rotation drives the lead screw to rotate synchronously. A nut connected to the error microphone holder is fitted on the lead screw. When the lead screw rotates, the nut moves along the lead screw axis, i.e., the guide direction of the slide rail, thereby driving the holder and the error microphone to move along the X or Y direction of the slide rail.

[0079] Understandably, the motor drives the lead screw to rotate, and through the cooperation of the nut and the lead screw, the retainer moves along the guide rail. After moving to the target position, the four-point locking device applies clamping force to the corresponding point, locking the retainer on the guide rail to prevent displacement.

[0080] S104 includes the following steps: S1041: The active noise reduction controller obtains the target spatial coordinates (X, Y) and target deflection angle α from the pre-trained neural network model, which are calculated based on the current air outlet blade angle, air volume and engine fan speed.

[0081] The target spatial coordinates define the planar position that the error microphone should reach within the plane of the device slide rail, and the angle α defines the angle relationship between the microphone's pickup axis and the airflow axis of the outlet.

[0082] In some embodiments, the output of the neural network is not an abstract instruction, but a set of spatial parameters with clear physical meaning. For example, coordinates (X, Y), which take a certain origin on the device frame, such as the leftmost end of the slide rail, as a reference, and correspond to the extreme point of the noise sound pressure in the spatial distribution map near the air outlet.

[0083] The target deflection angle α is proposed based on an acoustic principle: in order to most effectively collect airflow noise from a specific angle, the sensitive axis of the microphone should be directly facing the direction of the noise, that is, opposite to the direction of the airflow from the outlet.

[0084] The air outlet blade angle obtained by the controller from the CAN bus directly determines the airflow direction. The calculation of α is essentially mapping the physical deflection angle of the air outlet blades to the pickup angle that the error microphone needs to compensate for.

[0085] As can be seen, in this embodiment, air volume, rotation speed, and blade angle are mapped into a two-dimensional execution task sheet containing position and direction via a neural network.

[0086] S1042: The controller compares the target coordinates (X, Y) with the current position coordinates fed back by the displacement sensor integrated on the error microphone holder, and generates a position deviation signal.

[0087] The position deviation signal is input to a motor driver chip, which outputs a corresponding pulse sequence and direction signal to drive the motor to rotate. The motor's output shaft is connected to a lead screw via a coupling. The rotational motion of the lead screw is converted into linear motion of a nut meshing with the lead screw and fixed to the bottom of the error microphone holder. This causes the entire holder and the microphone on it to move along a linear slide rail until the deviation between the displacement sensor feedback coordinates and the target coordinates is less than a set threshold.

[0088] In some embodiments, physical displacement is converted into changes in resistance or the number of light pulses, thereby obtaining a real-time position electrical signal. The controller compares the electrical signal values ​​of the target position and the actual position; the difference is the deviation. The motor drive chip emits pulses according to the magnitude and sign of this deviation, adjusting the frequency and number of pulses.

[0089] S1043: While the position moves, the controller acquires the target deflection angle α; the four-point locking device consists of four electric push rods, which are arranged symmetrically in a cross shape around the error microphone holder.

[0090] The controller calculates the torque that needs to be applied to the microphone body based on the target deflection angle α, and decomposes it into linear forces F1 to F4 that need to be applied at four points.

[0091] For example, when the microphone needs to tilt up, the controller sends an extension command to the two lower motorized push rods and a retraction or hold command to the two upper motorized push rods, causing the lower push rods to exert an upward thrust on the microphone body while the upper push rods exert a smaller restraint force, thereby causing the microphone to tilt and rotate about a pivot point within its holder.

[0092] In some embodiments, using a single rotary motor with gears results in a complex structure that is difficult to install in confined spaces. Using four independently controlled miniature electric actuators provides greater flexibility. The force at each point corresponds to a vector. By controlling the magnitude and direction of these four vectors through pushing or pulling, a net torque can be synthesized to rotate the microphone body about its center of mass or a specific fulcrum.

[0093] The controller decomposes the target angle α into pitch and roll components. Based on the geometric relationship of the push rod layout, it calculates the current required for each push rod to achieve the desired extension and retraction. This enables rapid and continuous angle adjustment. Furthermore, the coordinated action of the four points can firmly lock the microphone, maintaining angle stability even under vehicle vibration conditions.

[0094] S1044: Integrates a MEMS tilt sensor on the error microphone holder for real-time measurement of the microphone barrel's current pitch and roll angles.

[0095] The controller continuously reads the data from the tilt sensor and compares it with the target angle α; Based on the angle deviation, the controller adjusts the control signals to the four electric actuators, such as adjusting the actuator stroke, until the measured angle stabilizes within the allowable error range of the target angle α.

[0096] In some embodiments, a MEMS tilt sensor is integrated, and sensor feedback is used to correct execution errors, thereby achieving adaptive adjustment and keeping the microphone in the optimal acquisition posture.

[0097] S105: The noise signal at the target location is collected using the error microphone adjusted in step S104, and the noise signal is transmitted to the active noise cancellation controller.

[0098] In some embodiments, an electret condenser microphone is used as the error microphone, installed in the circular mounting hole of the error microphone holder and secured by a four-point locking device, with the microphone pickup head facing the airflow direction of the air outlet. The analog noise signal output by the microphone is transmitted to the signal conditioning module. The signal conditioning module has a built-in active bandpass filter, operational amplifier, and isolation circuit to filter the weak signal, remove high-frequency interference and low-frequency vibration noise, and then amplify the signal to the 0-5V standard range. The isolation circuit avoids the influence of vehicle voltage fluctuations on the signal. The conditioned signal is transmitted to the active noise cancellation controller through the analog signal interface.

[0099] S106: The active noise cancellation controller controls the headrest speakers at the corresponding positions to emit canceling sounds with the same amplitude but opposite direction as the noise signal transmitted in step S105, based on the occupant position information identified in step S101. At the same time, it retains 20-30dB of natural wind sound through a psychoacoustic algorithm. If the occupant manually selects the noise cancellation position, the noise cancellation operation will be performed according to the manual selection instruction first.

[0100] like Figure 5 As shown, S106 includes the following steps: S1061: The active noise cancellation controller receives the binary encoded signal of the driver and passengers' positions, as well as the transmitted noise analog signal; it reads the manual noise cancellation position command from the cab touch panel via the LIN bus. If a valid manual command exists, it marks the position command as having higher priority than the automatic recognition signal; if no manual command exists, it locks the automatic recognition position signal.

[0101] In some embodiments, the active noise cancellation controller receives binary codes representing the occupant's location from a facial recognition system, with each location corresponding to a unique code. It receives analog noise signals transmitted from an error microphone via an isolated analog signal input interface on the controller. The controller communicates with the central touchscreen panel in the driver's cab via a LIN bus, reading manual noise cancellation position commands from the panel. If a manual command conforming to the protocol format is read, its priority is marked as high in the controller's internal register, while the automatically recognized position signal is marked as low priority. If no valid manual command is read, the automatically recognized position signal is locked as high priority. This priority determination allows for rapid response to occupant manual operations while avoiding conflicts between automatic and manual commands, thus improving the reliability of the control logic.

[0102] S1062: The received analog noise signal is input to the signal conditioning module for bandpass filtering, signal amplification, and then converted into a digital signal; the controller calls the phase inversion algorithm to perform a 180° phase flip on the digital signal to generate an initial canceled digital signal.

[0103] S1063: The controller retrieves the pre-stored correspondence between the position and the headrest speaker channel based on the locked position signal, and enables the headrest speaker channel at the corresponding position; by reading the impedance and rated power parameters of the channel speaker, it adjusts the output power of the cancellation signal to match the speaker operating parameters.

[0104] S1064: Converts the cancellation signal into an analog signal, amplifies it through the power amplifier module, and outputs it to the enabled headrest speaker; collects the noise-reduced mixed signal through the feedback microphone built into the headrest, transmits it to the controller for comparison with the original noise signal, and adjusts the amplitude and phase of the cancellation signal based on the comparison result until the noise amplitude in the mixed signal is lower than the preset threshold.

[0105] In some embodiments, the output of the cancellation signal is achieved through D / A conversion and power amplification, and the parameters of the cancellation signal are corrected to ensure that the noise reduction effect is stable and meets the standard.

[0106] S106 also includes the following steps: S2061: In the active noise cancellation controller, two processing paths are set up in parallel. The first path is a full-band active noise cancellation processing path, and the second path is a psychoacoustic processing path.

[0107] The psychoacoustic processing path incorporates a multi-order bandpass filter bank and a gain control unit. The bandpass filter bank separates high-frequency noise signals above 800Hz, and the gain control unit applies a fixed -25dB attenuation to the high-frequency signal.

[0108] In some embodiments, the active noise cancellation controller can be configured with a multi-core DSP or FPGA chip, enabling parallel processing. The first path executes a standard active noise cancellation algorithm, inverting noise across the entire frequency band. The second path is specifically designed for psychoacoustic needs and is a programmable digital filter bank. This filter bank, by cascading multiple second-order IIR filters, forms a steep cutoff characteristic at 800Hz, accurately separating high-frequency wind noise components from the original noise.

[0109] The gain control unit is a digital multiplier that multiplies the separated high-frequency signal by a fixed coefficient. This attenuation value was determined through real-vehicle testing to achieve the optimal balance between noise reduction and a natural sound.

[0110] S2062: Set up a digital mixer to mix the full-band inverted signal processed by the first channel with the attenuated high-frequency retained signal output by the second channel.

[0111] During mixing, the inverted signal processed by the first path is mainly used for low- and mid-frequency signals below 800Hz, while the attenuated signal output by the second path is mainly used for high-frequency signals above 800Hz. A smooth transition between frequency bands is achieved through a cross-gradient algorithm.

[0112] S2063: A manual control panel with a touch area is installed on the center console of the driver's cab. The manual control panel includes five options: automatic mode, driver's mode, passenger's mode, all-vehicle mode, and off mode. Each option corresponds to a numerical code. The currently selected code on the control panel is transmitted to the active noise cancellation controller in real time.

[0113] S2064: The logic arbitration unit of the active noise cancellation controller is equipped with a dual-input priority judgment module. This module connects to the manual control panel to transmit command codes, and also connects to a facial recognition system to obtain facial recognition result codes. When the manual control panel is in any mode other than automatic mode, the priority judgment module directly adopts the manual command code as the final control command.

[0114] In some embodiments, the logic arbitration unit is a module in the controller's main program that can continuously poll the data from the two input ports. Both manual instruction encoding and facial recognition encoding are converted into a unified internal format, such as using 4-bit binary numbers to represent different position combinations.

[0115] The priority judgment module consists of a set of conditional statements. It checks whether the manual command code is equal to a specific value in automatic mode; if not, it uses the manual command as the final output.

[0116] If so, facial recognition encoding is then used. The priority determination module also records the history of state transitions to prevent oscillations under boundary conditions.

[0117] In this way, when a user manually selects a mode based on their needs, the system switches to manual mode. Automatic mode, as the default option, ensures that the system operates intelligently in most cases without user intervention.

[0118] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0119] It should be understood that when an element or layer is said to be connected or coupled to another element or layer, it may be directly connected or coupled to said other element or layer, or there may be intermediate elements or layers. Conversely, when an element is said to be directly connected or coupled to another element or layer, there are no intermediate elements or layers. Similar figures in all figures indicate similar elements. As used herein, terms and / or include any and all combinations of one or more of the associated listed items.

[0120] Spatially relative terms, such as under, below, lower, above, and above, may be used here to describe the relationship between one element or feature and another, as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation other than those shown in the figure. For example, if the device in the figure were flipped over, the element described as being under or below another element or feature would be facing above that element or feature. Thus, the exemplary term "below" can include both "above" and "below." Other orientations (rotation 90 degrees or other orientations) may be adopted by the device, and the spatially relative terms used herein will be interpreted accordingly.

[0121] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the expression within this document. As used herein, the singular forms "one," "an," and "this" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that, when used in this specification, the terminology includes the presence of the stated feature, integer, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0122] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An active noise reduction device for the air vents of a commercial vehicle cab, characterized in that, include: The outer frame (1) has an error microphone holder (6) in the middle. The inner sidewall of the outer frame (1) is provided with a slide rail (3); A lead screw (4) is fixed on the error microphone holder (6); one end of the lead screw (4) is slidably connected to the slide rail (3); the other end of the lead screw (4) is connected to a motor (5); The error microphone holder (6) is set in the middle of the outer frame (1) via a lead screw (4); The error microphone holder (6) has a mounting hole (7) in the middle.

2. The active noise reduction device for the air vents of a commercial vehicle cab according to claim 1, characterized in that, An error microphone locking mechanism (8) is provided on the inner wall of the mounting hole (7).

3. The active noise reduction device for the air vents of a commercial vehicle cab according to claim 1, characterized in that, Bolt holes (2) are provided at the four ends of the outer frame (1).

4. A method for active noise reduction of the air vents in the cab of a commercial vehicle, characterized in that, The method is based on the active noise reduction device for the air vents of a commercial vehicle cab as described in any one of claims 1 to 3; the method includes: S101: Install facial recognition systems in the driver's cab, passenger's cab, and driver and passenger's sleeper berths of the commercial vehicle cab. By collecting images of the cab and combining them with body temperature characteristics, identify whether there are drivers or passengers in the cab. S102: Based on the obtained occupant identification results and the air conditioning status, if there are occupants and the air conditioning is on, the active noise cancellation system will be activated. S103: An active noise reduction device is installed at the air conditioning vent in the cab of a commercial vehicle. The active noise reduction device is connected and fixed to the interior panel through bolt holes. The air conditioning vent blade angle, air volume and engine fan speed information are obtained in real time through CAN. S104: Based on the acquired information of air conditioner vent blade angle, air volume and engine fan speed, the motor of the active noise reduction device drives the lead screw to move along the slide rail, and the four-point locking device applies different forces to different points, so that the error microphone moves to the target position and is adjusted to a posture that matches the vent angle. S105: The noise signal at the target location is collected through the adjusted error microphone and transmitted to the active noise cancellation controller; S106: The active noise cancellation controller controls the headrest speakers at the corresponding positions to emit a canceling sound with the same amplitude but opposite direction as the noise signal transmitted in step S105, based on the identified driver and passenger position information, and retains 20-30dB of natural wind sound through psychoacoustic algorithms.

5. The active noise reduction method for the air vents of a commercial vehicle cab according to claim 4, characterized in that, S101 includes the following steps: Multispectral cameras are embedded in the top and side walls of the driver's cab, passenger's cab, and sleeper area. The cameras use visible light and near-infrared dual-channel sensors to capture the contour information of the driver and passengers. An infrared thermal imaging probe is installed below each camera, with the probe's coverage overlapping the camera's field of view, to acquire real-time surface temperature distribution data of the target area. The detection data from the camera and infrared thermal imaging probe are transmitted to the controller via the CAN bus. The controller processes the visual features and thermal signals synchronously, and based on the YOLOv5 architecture neural network model, the input layer receives dual-channel data streams, and the output layer generates a binary judgment result of the presence status of the driver and passengers.

6. The active noise reduction method for the air vents of a commercial vehicle cab according to claim 4, characterized in that, S102 includes the following steps: Connect the output of the facial recognition system to the input of the logic judgment module so that the driver and passenger information identified by the facial recognition system can be transmitted to the logic judgment module. An air conditioning status detection device is installed on a commercial vehicle. The output of the air conditioning status detection device is connected to another input of the logic judgment module, so that the air conditioning on status information detected by the air conditioning status detection device is transmitted to the logic judgment module. In the logic judgment module, a judgment rule is set. When the system receives information about the presence of drivers and passengers from the facial recognition system and information about the air conditioning being turned on from the air conditioning status detection device, a start signal is output. Connect the output of the logic judgment module to the control input of the active noise cancellation system. When the logic judgment module outputs a start signal, the active noise cancellation system receives the signal and starts.

7. The active noise reduction method for the air vents of a commercial vehicle cab according to claim 4, characterized in that, S103 includes the following steps: Measure the inner length, width and duct depth of the air outlet of the commercial vehicle's air conditioning system, adjust the nested expansion joint of the outer frame of the active noise reduction device, and lock the frame size after turning the locking knob on the side of the frame to match the inner edge size of the air outlet and the depth to match the duct depth. Push the adjusted outer frame into the air duct of the air conditioning vent, so that the front end of the frame is flush with the air vent decorative panel. Mark the drilling points on the corresponding position of the interior panel through the bolt holes of the device, and then take out the active noise reduction device. Select a twist drill bit that matches the bolt diameter of the active noise reduction device, align it with the marked position and drill a hole in the interior panel, then tap the hole with a matching tap. Align the air outlet duct of the outer frame with the bolt holes of the device and the tapping holes of the interior panel, and tighten the bolts twice to complete the device fixation; insert the slide rail into the slot of the inner wall of the frame and fix it, embed the screw into the guide groove of the slide rail, and fix the motor in the reserved position of the end plate of the frame through the flange.

8. The active noise reduction method for the air vents of a commercial vehicle cab according to claim 4, characterized in that, S104 includes the following steps: S1041: The active noise reduction controller obtains the target spatial coordinates (X, Y) and target deflection angle α calculated based on the current air outlet blade angle, air volume and engine fan speed from the pre-trained neural network model; The target spatial coordinates define the planar position that the error microphone should reach in the plane of the device slide rail, and the angle α defines the angle relationship between the microphone's main pickup axis and the main airflow axis of the air outlet. S1042: The controller compares the target coordinates (X, Y) with the current position coordinates fed back by the displacement sensor integrated on the error microphone holder and generates a position deviation signal; S1043: While the position moves, the controller acquires the target deflection angle α; the four-point locking device consists of four electric push rods, which are arranged symmetrically in a cross shape around the error microphone holder; The controller calculates the torque that needs to be applied to the microphone body based on the target deflection angle α, and decomposes it into linear forces F1 to F4 that need to be applied at four points. S1044: Integrates a MEMS tilt sensor on the error microphone holder for real-time measurement of the microphone barrel's current pitch and roll angles.

9. The active noise reduction method for the air vents of a commercial vehicle cab according to claim 4, characterized in that, S106 includes the following steps: The active noise cancellation controller receives the position signal of the driver and passengers and the noise simulation signal collected by the error microphone, and determines the final noise cancellation area position signal according to the priority of manual control commands and automatic recognition commands. The active noise cancellation controller conditions and performs analog-to-digital conversion on the noise analog signal, and generates an initial cancellation digital signal through a phase inversion algorithm; The active noise cancellation controller activates the corresponding headrest speaker channel stored in advance based on the noise cancellation area location signal, and adjusts the output power of the initial cancellation digital signal based on the speaker parameters. The active noise cancellation controller converts the adjusted cancellation digital signal into an analog signal and amplifies it before outputting it to the headrest speaker. It also collects the noise-cancelled mixed signal through a feedback microphone and adjusts the amplitude and phase of the cancellation signal until the noise reduction effect meets the preset requirements.

10. The active noise reduction method for the air vents of a commercial vehicle cab according to claim 4, characterized in that, S106 also includes the following steps: In the active noise cancellation controller, two processing paths are set up in parallel: the first path is a full-band active noise cancellation processing path, and the second path is a psychoacoustic processing path. Set up a digital mixer to mix the full-band inverted signal processed by the first channel with the attenuated high-frequency preserved signal output by the second channel; A manual control panel with a touch area is installed on the center console of the driver's cab; the manual control panel has five options: automatic mode, driver's mode, passenger's mode, all-vehicle mode and off mode, and each option corresponds to a digital code; the currently selected code on the control panel is transmitted to the active noise cancellation controller in real time; The logic arbitration unit of the active noise cancellation controller is equipped with a dual-input priority judgment module. The dual-input priority judgment module is connected to the manual control panel to transmit command codes, and the dual-input priority judgment module is also connected to the facial recognition system to obtain facial recognition result codes.

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