Vehicle tail door low-frequency road noise control system and control method

Abstract

The invention discloses a vehicle tail door low-frequency road noise control system which comprises a supporting structure arranged between a tail door and a vehicle body and used for supporting the tail door after the tail door is closed relative to the vehicle body; the first sensing unit is arranged on the tail gate and is used for acquiring a vibration response signal of the tail gate; wherein the supporting structure comprises a plurality of supporting parts with adjustable supporting force, and the plurality of supporting parts are all connected to a control module; the control module is connected with the first sensing unit and is configured to adjust the supporting force of the supporting piece according to the vibration response signal. The invention further discloses a control method applied to the control system. The problem that in the prior art, due to the fact that the rigidity of a connecting structure between the tail door and a vehicle body is fixed, the modal frequency cannot be dynamically adjusted along with the driving working condition can be solved, then resonance of the tail door within the 20-40 Hz road surface excitation frequency band is avoided, and low-frequency road noise and structural abnormal sound caused by resonance are reduced.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, specifically to a low-frequency road noise control system and control method for a vehicle tailgate. Background Technology

[0002] As users demand greater quietness and comfort from their vehicles, road noise has become a significant issue. This problem is even more pronounced in new energy vehicles, which lack the engine to mask it. Low-frequency road noise (20–40Hz), in particular, is more easily perceived by users due to its higher energy levels. It not only affects user comfort but can also trigger physiological and psychological reactions such as fatigue and stress, negatively impacting user health.

[0003] To reduce vehicle noise and improve the driving experience, related technologies typically optimize the transmission paths from the tires to the suspension. However, as one of the response points, the tailgate's rigid and torsional modes are easily excited, leading to forced responses and causing low-frequency resonance that generates road noise. To address this, related technologies connect the tailgate to the vehicle body using rigid or semi-rigid connectors such as hinges, struts, and latches, and incorporate buffer blocks for limiting and constraining. Therefore, the tailgate's modal characteristics are primarily determined by the physical parameters of these connecting structures. Because the stiffness of these structures is fixed and cannot be dynamically adjusted according to driving conditions, the tailgate is prone to resonance under specific road surface excitations, especially in the 20–40 Hz low-frequency range, which can easily cause vibration and noise problems. Summary of the Invention

[0004] In view of the above problems, this application provides a low-frequency road noise control system and control method for vehicle tailgates, which aims to solve the problem in the prior art that the modal frequency cannot be dynamically adjusted according to driving conditions due to the fixed stiffness of the connection structure between the tailgate and the vehicle body, thereby avoiding resonance of the tailgate in the 20-40 Hz road excitation frequency band and reducing the low-frequency road noise and structural abnormal noise caused therefrom.

[0005] According to one aspect of the embodiments of this application, a low-frequency road noise control system for a vehicle tailgate is provided, comprising: a support structure disposed between the tailgate and the vehicle body, for providing support for the tailgate after the tailgate is closed relative to the vehicle body; a first sensing unit disposed on the tailgate and for collecting vibration response signals of the tailgate; wherein the support structure includes a plurality of support members with adjustable support force, and the plurality of support members are all connected to a control module; the control module is connected to the first sensing unit, and the control module is configured to adjust the support force of the support members according to the vibration response signals.

[0006] In one exemplary embodiment of this application, the support member is configured as an element that generates a change in support force based on its own internal pressure regulation. The control module includes a pressure regulation unit, which is connected to the support member through a fluid channel and is configured to regulate the internal pressure of the support member.

[0007] In one exemplary embodiment of this application, the support member is an inflatable airbag, the pressure control unit is an air source, and the airbag is inflated and deflated by the air source to switch between an inflated state and a retracted state; wherein, the airbag is configured to provide elastic support with variable stiffness in the inflated state and to return to the retracted state after deflation to allow the tailgate to open and close normally.

[0008] In one exemplary embodiment of this application, each airbag is connected to a common air source through an independent fluid channel, and each fluid channel is equipped with a solenoid valve. The solenoid valve is controlled by a control module to control the inflation, pressure holding and depressurization actions of the corresponding airbag.

[0009] In one exemplary embodiment of this application, the tailgate is connected to the vehicle body via a hinge and a door lock, with the hinge and door lock located on opposite sides of the tailgate; with the vertical central axis of the tailgate about the hinge side and the door lock side as the axis of symmetry, multiple support members are symmetrically installed on the edge area of ​​the tailgate.

[0010] In one exemplary embodiment of this application, four support members are provided, two of which are symmetrically installed on the edge area of ​​the tailgate near the door lock, and the other two are symmetrically installed on the edge areas on both sides of the middle of the tailgate.

[0011] In one exemplary embodiment of this application, the system further includes: a second sensing unit, including a forward-facing camera and / or lidar equipped in the vehicle driver assistance system, for acquiring road surface contour information in front of the vehicle; and a control module connected to the second sensing unit, wherein the control module is configured to adjust the support force of the support member according to the road surface contour information.

[0012] In one exemplary embodiment of this application, the system further includes: a third sensing unit, including an acceleration sensor on a shock absorber in the vehicle chassis system, for acquiring dynamic excitation data during vehicle operation; and a control module connected to the third sensing unit, wherein the control module is configured to adjust the support force of the support member according to the dynamic excitation data.

[0013] According to a second aspect of the present application, a method for controlling low-frequency road noise in a vehicle tailgate is provided, applied to the aforementioned low-frequency road noise control system for a vehicle tailgate. The method includes: acquiring vehicle speed information and tailgate status signal; acquiring a vibration response signal collected by a first sensing unit when the vehicle speed information is greater than a preset vehicle speed and the status signal is in a closed state; and adjusting the support force of the support member according to the vibration response signal. According to a third aspect of the embodiments of this application, a method for controlling low-frequency road noise in a vehicle tailgate is provided. The method includes: acquiring vehicle speed information and tailgate status signal; when the vehicle speed information is greater than a preset vehicle speed and the status signal is in a closed state, acquiring road surface contour information in front of the vehicle through the aforementioned second sensing unit; determining a predicted road surface type based on the road surface contour information; pre-adjusting the support force of at least some support members according to the predicted road surface type; or acquiring dynamic excitation data during vehicle operation through the aforementioned third sensing unit; determining the actual road surface type based on the dynamic excitation data; and pre-adjusting the support force of at least some support members according to the actual road surface type.

[0014] According to a fourth aspect of the embodiments of this application, a method for controlling low-frequency road noise in a vehicle tailgate is provided. The method includes: acquiring vehicle speed information and tailgate status signal; when the vehicle speed information is greater than a preset vehicle speed and the status signal is in a closed state, determining a predicted road surface type based on road surface contour information in front of the vehicle acquired by a second sensing unit; performing a first pre-adjustment of the support force of at least some support members according to the predicted road surface type; determining the actual road surface type based on dynamic excitation data during vehicle operation acquired by a third sensing unit; and performing a second pre-adjustment of the support force of at least some support members according to the actual road surface type.

[0015] This application, by setting multiple adjustable support components between the tailgate and the vehicle body, and cooperating with the first sensing unit through the control module, can achieve dynamic adaptive adjustment of the constraint stiffness between the tailgate and the vehicle body based on the vibration response signal of the tailgate collected by the first sensing unit. Compared with the traditional method that relies on mechanical connecting parts with fixed stiffness, it can actively adjust the distribution of all or part of the support stiffness according to the actual vibration response of the tailgate during the operation of the vehicle, so that the rigid body mode and torsional mode of the tailgate can effectively avoid the key excitation frequency band of 20-40 Hz, and significantly suppress the occurrence of low frequency resonance.

[0016] The above description is merely an overview of the technical solutions of the embodiments of this application. In order to better understand the technical means of the embodiments of this application and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of this application more obvious and understandable, specific implementation methods of this application are described below. Attached Figure Description

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

[0018] Figure 1 A structural block diagram of the vehicle tailgate low-frequency road noise control system according to an embodiment of this application is shown; Figure 2 This illustration shows a schematic diagram of the connection between the support member described in the embodiment of this application and the vehicle body; Figure 3 This illustration shows a schematic diagram of the support member described in an embodiment of this application being installed on the tailgate; Figure 4 This illustration shows the effect of the vehicle tailgate low-frequency road noise control system according to an embodiment of this application; Figure 5 A flowchart illustrating the low-frequency road noise control method for vehicle tailgates according to an embodiment of this application is shown. Figure 6 A flowchart illustrating another vehicle tailgate low-frequency road noise control method according to an embodiment of this application is shown; Figure 7 A flowchart illustrating another vehicle tailgate low-frequency road noise control method according to an embodiment of this application is shown; Figure 8 A flowchart illustrating another vehicle tailgate low-frequency road noise control method according to an embodiment of this application is shown.

[0019] Explanation of icon numbers: 1-Support structure, 11-Support component, 2-First sensing unit, 3-Control module, 31-Pressure regulation unit, 4-Fluid channel, 5-Solenoid valve, 6-Second sensing unit, 7-Third sensing unit, 8-Tailgate, 81-Hinge, 82-Door lock, 9-Body body.

[0020] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0022] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0023] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be noted that the technical features involved in the various embodiments described below can be combined with each other as long as they do not conflict with each other. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present application, and should not be construed as limiting the present application.

[0024] It should also be noted that in the description of this application, X, Y and Z are three mutually perpendicular directions in a three-dimensional coordinate system, and the terms "up", "down", "front", "back", "left", "right", "inner", "outer" and other terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the technical solution of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] In existing technologies, automobile tailgates are connected to the vehicle body via rigid or semi-rigid connectors such as hinges, struts, and latches. Their modal characteristics are primarily determined by the physical parameters of these connecting structures. Because the stiffness of such structures is fixed and cannot be dynamically adjusted according to driving conditions, the tailgate is prone to resonance under specific road surface excitations, especially in the low-frequency range of 20–40 Hz, which can easily lead to vibration and noise problems. To solve this problem, a variable stiffness support mechanism needs to be introduced to achieve active control of the tailgate's constraint state.

[0026] like Figures 1 to 3As shown, this embodiment provides a low-frequency road noise control system for a vehicle tailgate, including a support structure 1 and a first sensing unit 2. The support structure 1 is disposed between the tailgate 8 and the vehicle body 9, and is used to provide support for the tailgate 8 after it is closed relative to the vehicle body 9. The first sensing unit 2 is disposed on the tailgate 8 and is used to collect the vibration response signal of the tailgate 8. The support structure 1 includes multiple support members 11 with adjustable support force, and each of the multiple support members 11 is connected to a control module 3. The control module 3 is connected to the first sensing unit 2 and is configured to adjust the support force of the support members 11 according to the vibration response signal, thereby dynamically adjusting the spatial constraint stiffness distribution of the tailgate 8, increasing the overall modal frequency of the tailgate 8 and making it avoid the resonance frequency band of 20-40 Hz, and reducing the vibration transmission and structural radiation noise of the tailgate 8.

[0027] Specifically, the aforementioned support structure 1 refers to the set of components that participate in the load-bearing of the tailgate 8 and affect its boundary constraints after the tailgate 8 is closed. It can be installed on the vehicle body 9 or on the tailgate 8, and it only needs to provide support for the tailgate 8 between the tailgate 8 and the vehicle body 9 after the tailgate 8 is closed relative to the vehicle body 9. Among them, the support member 11 may include elastic contact elements and power actuation elements. The power actuation elements may be, but are not limited to, cylinders, hydraulic cylinders, electric push rods, etc., and the elastic contact elements may be rubber sleeves installed on the movable end of the power actuation elements.

[0028] In this way, the power actuator can adjust the support force under the control of the control module 3; and the elastic contact element itself has elastic characteristics, which can passively absorb vibration energy during the support process, reduce the vibration transmission level and radiated noise intensity of the tailgate 8 structure, not only improve the vehicle's NVH (Noise, Vibration, and Harshness) performance, but also enhance the durability of the tailgate 8 system.

[0029] The first sensing unit 2 may include one or more vibration sensors. These sensors are mounted on the tailgate 8, located near the mounting point of the support member 11 or in an area with a large modal amplitude, and are used to collect the acceleration vibration signal, i.e., the vibration response signal, of the tailgate 8 in real time. The vibration sensor may be a triaxial capacitive MEMS (Micro-Electro-Mechanical System) accelerometer, which can effectively meet the vibration monitoring requirements. It is understood that in other embodiments, the vibration sensor may also be a piezoelectric or fiber optic accelerometer; this is not limited here.

[0030] In this way, the first sensing unit 2 can continuously collect the acceleration data of the tailgate 8 in the X, Y and Z directions, focusing on capturing the vibration energy distribution in the vertical jumping and torsional directions; after the data is filtered, it is sent to the control module 3 to identify the main frequency components and provide a basis for subsequent modal judgment.

[0031] Control module 3 can be an embedded controller, integrating at least a communication interface and an FFT (Fast Fourier Transform) module. The communication interface can receive data signals from various sensors, and the FFT module can perform FFT transformation on the received vibration response signal and identify the main frequency components in the vibration response signal. Simultaneously, the control algorithm is deployed in control module 3. By extracting the energy percentage in the 20–40 Hz frequency band, if it exceeds a preset threshold (e.g., 70%), there is a risk of resonance. At this point, control module 3 initiates an adjustment program. The adjustment strategy uses a lookup table method combined with interpolation calculations. Based on the current vehicle speed, load state, and historical adjustment records, it selects an initial adjustment scheme from a pre-calibrated pressure matrix to obtain the required pressure increment for each support component 11, and then fine-tunes and optimizes it to the minimum vibration state, thereby achieving dynamic adaptive adjustment of the support force of the support component 11. It is understood that control module 3 can also be integrated into the vehicle's body domain controller or chassis domain controller, and achieve data interaction and collaborative control with various sensing units, human-machine interaction systems, and other electronic control units through the vehicle communication network.

[0032] By adopting the above implementation method, the constraint stiffness of the tailgate 8 is transformed from "statically locked" to "dynamically adjustable", which significantly improves the NVH performance of the whole vehicle. By actively adjusting the support stiffness distribution, the low-frequency resonance phenomenon caused by improper modal matching is effectively avoided, and the vibration response amplitude of the tailgate 8 and the noise level inside the vehicle are reduced. At the same time, the system has good environmental adaptability and can maintain stable control under different vehicle speeds, loads and road conditions. This allows the rigid body mode and torsional mode of the tailgate 8 to effectively avoid the critical excitation frequency band of 20-40 Hz, suppress the occurrence of low-frequency resonance, and enhance ride comfort and the durability of the tailgate 8 system.

[0033] In some embodiments, the support member 11 is configured as a component that generates support force changes based on its own internal pressure regulation, including but not limited to pneumatic components, hydraulic components, airbags, etc.; the control module 3 includes a pressure regulation unit 31, which can be selected as a pneumatic system based on an air source or a hydraulic system based on a hydraulic source, depending on the type of fluid medium. The pressure regulation unit 31 is connected to the support member 11 through a fluid channel 4 and is configured to regulate the internal pressure of the support member 11. In this way, the pressure regulation unit 31 can regulate the internal pressure of the support member 11 by performing pressurization, pressure holding, and pressure release actions on the support member 11.

[0034] For example, in this embodiment, the support member 11 is an inflatable airbag, and the pressure control unit 31 is the air source. The airbag is inflated and deflated by the air source to switch between an inflated state and a retracted state. The airbag is made of a flexible and pressure-resistant material, which can provide elastic support with variable stiffness in the inflated state and return to the retracted state after deflation to allow the tailgate 8 to open and close normally. On the one hand, using an airbag as the support member 11 can combine the elastic contact element and the power actuation element, and at the same time have the functions of elastic support and adjustable support force. On the other hand, as a deformable support unit, the airbag generates axial thrust after inflation, which lifts the tailgate 8 slightly upward and presses it against the sealing surface of the body 9, enhancing the overall connection stiffness. At the same time, due to its nonlinear stiffness characteristics, the stiffness increases with the increase of pressure, which can realize stepped stiffness adjustment. After deflation, it can also quickly return to its original position without affecting the convenience of opening the tailgate 8.

[0035] Specifically, the aforementioned inflatable airbag can be made of a multi-layer composite rubber-fabric structure, such as a three-layer composite structure: the inner layer is butyl rubber, which has excellent airtightness and anti-aging properties; the middle layer is polyester fiber woven mesh, which is used to withstand internal pressure and prevent excessive expansion; the outer layer is neoprene rubber coated fabric, which provides wear resistance, UV resistance and oil corrosion resistance; the overall structure is hot-pressed and vulcanized to form an integrated sealed cavity, which can withstand cyclic loads within a certain range (e.g., 0.1–1.0 MPa) without permanent deformation. Correspondingly, the fluid channel 4 can be made of PU (polyurethane) hose with a pressure rating of 1.5 MPa. The PU hose connects the airbag to the air source through a connector, forming a fluid channel 4 with an inflation circuit and an exhaust circuit; the air source can be an air tank with a rated pressure of 1.2 MPa.

[0036] In this way, when the control module 3 controls the pressure regulation unit 31 to perform the pressurization action, compressed air enters the airbag from the air tank through the fluid channel 4, causing it to expand to the inflated state and press against the inner side panel of the vehicle body 9 to form an elastic support; when the control module 3 controls the pressure regulation unit 31 to perform the depressurization action, the gas inside the airbag is discharged through the fluid channel 4, and the airbag height retracts to the storage state to avoid interference with the vehicle body 9.

[0037] It is understood that in other embodiments, the airbag may also be made of high-performance materials such as fluororubber or aramid fiber, and this is not limited here.

[0038] In some embodiments, such as Figure 1As shown, each airbag is connected to a common air source through an independent fluid channel 4, and each fluid channel 4 is equipped with a solenoid valve 5. The solenoid valve 5 is controlled by the control module 3 and is used to control the inflation, pressure holding, and depressurization actions of the corresponding airbag. By establishing isolated air supply paths and control actuators, the gas flow rate of each airbag can be controlled individually, achieving independent and precise control of each airbag.

[0039] Specifically, the aforementioned solenoid valve 5 can be a high-speed response solenoid valve 5 with PWM pressure regulation function (such as the SMC-VQ51 series solenoid valve 5). This solenoid valve 5 has a response time of less than 10 ms and can accurately control the gas flow rate. In this way, the control module 3 can drive the solenoid valve 5 of the corresponding fluid channel 4 to operate by outputting a PWM signal, controlling the required proportion of gas to flow into or out of the airbag, ensuring that the pressure between each airbag does not affect each other, and achieving fine control with millisecond-level response. At the same time, except for performing a pressure holding action after the airbag reaches the target pressure to keep the airbag in a stable pressure state, the gas flow rate can be adjusted and controlled by the solenoid valve 5 during the pressurization / depressurization actions to ensure sufficient adjustment accuracy. Moreover, during the depressurization action, it can also quickly release pressure and release the support force, improving control flexibility, thereby forming a precise and effective pressure control closed loop.

[0040] It is understood that in other embodiments, the solenoid valve 5 may also be a pilot-operated proportional valve, which is not limited here.

[0041] In some embodiments, such as Figure 3 As shown, the tailgate 8 is connected to the vehicle body 9 via hinges 81 and locks 82, with hinges 81 and locks 82 located on opposite sides of the tailgate 8. Multiple support members 11 are symmetrically installed on the edge area of ​​the tailgate 8, with the vertical central axis of the tailgate 8 about the hinge 81 side and the lock 82 side as the axis of symmetry. Installing support members 11 on the edge area of ​​the tailgate 8 does not reduce the function and performance of the original tailgate 8, nor does it affect the structural strength of the original vehicle body 9. Simultaneously, the symmetrical arrangement of multiple support members 11 about the vertical central axis of the hinge 81 side and the lock 82 side ensures even distribution of support force, guaranteeing a reasonable spatial distribution of support force and thus meeting the structural requirements of tailgates 8 for different vehicle models.

[0042] For example, such as Figure 3As shown, in this embodiment, there are four support members 11. Two support members 11 are symmetrically installed on the edge area of ​​the tailgate 8 near the door lock 82, which can enhance the constraint of the door lock 82 area and reduce force fluctuation. The other two support members 11 are symmetrically installed on the edge areas on both sides of the middle of the tailgate 8, which can play a bridging support role in the middle edge area of ​​the tailgate 8 and suppress the deflection deformation in the middle. Therefore, this four-point symmetrical arrangement can evenly distribute the support force, effectively suppress the three low-order modes of pitch, roll and torsion of the tailgate 8, and improve the torsional stiffness of the tailgate 8.

[0043] Furthermore, the mounting point of the support member 11 is located in the area where the reinforcing ribs of the inner panel of the tailgate 8 intersect, to ensure that the local structural strength is sufficient to withstand the reaction force generated by the support member 11.

[0044] Understandably, when the size of the tailgate 8 is large, the number of airbags can be expanded according to the size of the tailgate 8 structure, adding at least one additional airbag to enhance the support stiffness distribution in the edge area.

[0045] In some embodiments, such as Figure 1 As shown, the low-frequency road noise control system for the vehicle's tailgate also includes a second sensing unit 6. The second sensing unit 6 includes a forward-facing camera and / or lidar equipped in the vehicle's driver assistance system, used to acquire road surface contour information in front of the vehicle. The control module 3 is connected to the second sensing unit 6 and is configured to adjust the support force of the support member 11 according to the road surface contour information. In this way, by introducing external environmental perception through the second sensing unit 6, the support member 11 can be pre-controlled, improving control foresight and achieving "pre-vibration control," thereby advancing the control timing from passive response to active defense, significantly shortening the system response lag.

[0046] Specifically, in this embodiment, the second sensing unit 6 can use the HUAWEI-MDC vision module as a forward-facing camera. The forward-facing camera is installed in front of the vehicle (such as the upper center of the windshield), and its field of view covers the road area within a certain distance (such as 30–100 m). It identifies road surface contour information (including features such as road surface cracks, speed bumps, and potholes) through deep learning algorithms, and then transmits it to the vehicle domain controller via the vehicle Ethernet, and then forwards it to the control module 3. The control module 3 can establish or preset a road surface type-excitation intensity mapping table. This mapping table stores the correspondence between road surface types and excitation intensities. Based on this correspondence, it can execute corresponding adjustment schemes under specific conditions. For example, when a pothole is detected on the left side, the left airbag is pre-inflated to the first pre-inflation threshold (e.g., 0.8 MPa) and the right airbag is pre-inflated to the second pre-inflation threshold (e.g., 0.5 MPa) after a preset time (e.g., 1.5 seconds) to form asymmetrical support and suppress torsional vibration. When a continuous speed bump is detected, the full airbag is pre-inflated to the first pre-inflation threshold (e.g., 0.8 MPa) after a preset time (e.g., 1.5 seconds) to prepare for impact resistance.

[0047] In other embodiments, when a lidar is used as the second sensing unit 6, it can scan a road area at an angle of ±45° in front of the vehicle, construct a point cloud model of the terrain ahead, and calculate the road surface undulation to identify road surface contour information. Of course, the forward-looking camera and lidar can also cooperate to jointly identify road surface contour information to ensure the accuracy of road surface contour information identification.

[0048] In some embodiments, such as Figure 1 As shown, the vehicle tailgate low-frequency road noise control system also includes a third sensing unit 7. The third sensing unit 7 includes an acceleration sensor on the shock absorber in the vehicle chassis system, used to acquire dynamic excitation data during vehicle operation. The control module 3 is connected to the third sensing unit 7 and is configured to adjust the support force of the support member 11 according to the dynamic excitation data. Thus, by introducing driving behavior perception through the third sensing unit 7, the predictability and proactivity of the control strategy can be improved, effectively responding to sudden road impacts and further reducing the vibration peak and transient noise of the tailgate 8.

[0049] Specifically, the third sensing unit 7 in this embodiment can use the acceleration sensor built into the CDC (Continuous Damping Control) shock absorber, which can provide real-time feedback on the dynamic displacement and impact intensity of the suspension. The acceleration signal it acquires, as dynamic excitation data, can be transmitted to the chassis domain controller via the CAN FD bus and then forwarded to the control module 3. The control module 3 can determine the vehicle's driving state through the dynamic excitation data, thereby analyzing the road surface type of the current driving segment. Then, it executes the corresponding adjustment scheme according to the road surface type-excitation intensity mapping table. For example, if the vehicle body 9 is detected to be tilted (such as going over a bump on one side), the airbag on the compressed side is immediately pre-inflated to the first pre-inflation threshold (such as 0.8 MPa), and the airbag on the non-compressed side is pre-inflated to the second pre-inflation threshold (such as 0.6 MPa) to form asymmetrical support and suppress torsional vibration.

[0050] It is understood that the above-mentioned preset time and pre-inflation threshold are only exemplary references. In actual applications, the pre-inflation threshold and timing (including preset time) can be adjusted according to different calibrations (such as vehicle type, vehicle speed, load, etc.). This application embodiment does not limit this.

[0051] It is also understandable that the third sensing unit 7 and the second sensing unit 6 can be used in conjunction. The second sensing unit 6 and the third sensing unit 7 can simultaneously introduce external environment perception and driving behavior perception methods. This can not only pre-control the support component 11 in advance, improve the control foresight, achieve "pre-vibration control", and shorten the system response lag, but also improve the initiative of the control strategy, effectively cope with sudden road impacts, and further reduce the vibration peak and transient noise of the tailgate 8.

[0052] like Figure 4 As shown, a schematic diagram is provided illustrating the effect of a vehicle equipped with the vehicle tailgate low-frequency road noise control system of this application after passing through a cement joint with high excitation at a constant speed. The red line represents the road noise-vibration state without the vehicle tailgate low-frequency road noise control system of this application, while the green line represents the road noise-vibration state after using the vehicle tailgate low-frequency road noise control system for low-frequency road noise control. After using the vehicle tailgate low-frequency road noise control system for low-frequency road noise control, the low-frequency pressure noise in the rear row is significantly improved when the vehicle passes through a cement joint with high excitation at a constant speed, and the average noise in the rear row is reduced by 2.1 dB(A).

[0053] This application also provides a method for controlling low-frequency road noise at the tailgate of a vehicle. Please refer to the following for details. Figure 5 , Figure 5 This is a schematic flowchart illustrating a low-frequency road noise control method for a vehicle tailgate, as shown in an exemplary embodiment of this application. The method is applicable to the aforementioned low-frequency road noise control system for a vehicle tailgate, and includes at least steps S101 to S103, detailed below: S101, acquire vehicle speed information and tailgate status signal; Vehicle speed information can be obtained through wheel speed sensors, engine speed sensors, etc. The status signal of tailgate 8 can be obtained through Hall sensor or door lock 82 status. Based on the vehicle speed information and tailgate 8 status signal, it can be determined whether the vehicle is in motion and whether tailgate 8 is closed. Low-frequency road noise control of tailgate 8 is only activated when the vehicle is in motion (or the vehicle speed meets the conditions for low-frequency road noise control) and tailgate 8 is closed, in order to avoid meaningless energy loss.

[0054] S102, when the vehicle speed information is greater than the preset vehicle speed and the tailgate status signal is closed, the vibration response signal collected by the first sensing unit is acquired. In this embodiment, the vehicle is determined to be in motion by comparing a preset vehicle speed. The preset vehicle speed is set to 1 km / h. When the current vehicle speed exceeds 1 km / h, the vehicle is determined to be in motion. At the same time, the tailgate 8 is in a closed state. The first sensing unit 2 is activated to collect the vibration response signal of the tailgate 8 for subsequent analysis and identification by the control module 3.

[0055] Understandably, when the vehicle is traveling at a speed of 1-10 km / h, the road noise of the tailgate 8 is relatively low, and the low-frequency road noise control system can be used without activating it. In this regard, the preset speed can be set to 10 km / h. When the current speed exceeds 10 km / h, it is determined that the vehicle needs to perform low-frequency road noise control, thereby further reducing unnecessary energy consumption.

[0056] S103, adjusts the support force of the support component according to the vibration response signal.

[0057] Based on the aforementioned description of the vehicle tailgate low-frequency road noise control system, the control module 3 has frequency domain analysis capabilities. It can identify whether the current response energy of the tailgate 8 is concentrated in the 20–40 Hz frequency band based on the frequency domain analysis results of the vibration response signal, and start the support force adaptive adjustment program to adjust the support force of the support component 11 when a near resonance trend is detected. Using this method, the low-frequency road noise control process of the vehicle tailgate 8 can be initiated under specific conditions. Based on the vibration response signal of the tailgate 8 collected by the first sensing unit 2, the constraint stiffness between the tailgate 8 and the vehicle body 9 can be dynamically and adaptively adjusted. Compared with the traditional method that relies on fixed stiffness mechanical connectors, it can actively adjust the distribution of all or part of the support stiffness according to the actual vibration response of the tailgate 8 during the operation of the whole vehicle. This allows the rigid body mode and torsional mode of the tailgate 8 to effectively avoid the key excitation frequency band of 20-40Hz, and significantly suppress the occurrence of low-frequency resonance.

[0058] This application also provides a method for controlling low-frequency road noise at the tailgate of a vehicle. Please refer to the following for details. Figure 6 , Figure 6 This is a flowchart illustrating a low-frequency road noise control method for a vehicle tailgate, as shown in another exemplary embodiment of this application. This method is applicable to the aforementioned low-frequency road noise control system for a vehicle tailgate equipped with a second sensing unit 6, and includes at least steps S201 to S204, detailed below: S201, acquire vehicle speed information and tailgate status signal; The implementation methods and objectives of steps S201 and S101 are the same, and will not be repeated here.

[0059] S202, when the vehicle speed information is greater than the preset vehicle speed and the tailgate 8 is in the closed state, the road surface contour information in front of the vehicle is obtained through the second sensing unit 6 mentioned above. In response, if the current vehicle speed is greater than the preset vehicle speed and the tailgate 8 is in a closed state, the second sensing unit 6 is activated to obtain the road surface contour information in front of the vehicle for subsequent analysis and use by the control module 3.

[0060] S203, Determine the predicted road surface type based on road surface contour information; In response, the road surface contour information acquired by the second sensing unit 6 is the predicted information of the road area within a certain distance in front of the vehicle. The road surface type analyzed by the control module 3 based on this road surface contour information is also the predicted road surface type, which has a high probability of occurrence.

[0061] S204, based on the predicted road surface type, pre-adjust the support force of at least some of the supports.

[0062] Based on the description of the vehicle tailgate low-frequency road noise control system, the control module 3 can execute the corresponding adjustment scheme under specific road surface conditions to achieve pre-adjustment of the support force of the support member 11 and improve control efficiency.

[0063] By adopting this method, the external environment perception means can be introduced through the second sensing unit 6, and the support component 11 can be pre-controlled in advance, thereby improving the control foresight and realizing "pre-vibration control". This will advance the control timing from passive response to active defense stage and significantly shorten the system response lag time.

[0064] This application also provides a method for controlling low-frequency road noise at the tailgate of a vehicle. Please refer to the following for details. Figure 7 , Figure 7This is a schematic flowchart illustrating a low-frequency road noise control method for a vehicle tailgate, as shown in another exemplary embodiment of this application. This method is applicable to the aforementioned low-frequency road noise control system for a vehicle tailgate equipped with a third sensing unit 7, and includes at least steps S211 to S214, detailed below: S211, obtain vehicle speed information and tailgate status signal; The implementation methods and objectives of steps S211 and S101 are the same, and will not be repeated here.

[0065] S212, when the vehicle speed information is greater than the preset vehicle speed and the tailgate status signal is closed, the dynamic excitation data during the vehicle's driving process is obtained through the aforementioned third sensing unit. In response, when the current vehicle speed is greater than the preset vehicle speed and the tailgate 8 is in a closed state, the third sensing unit 7 is activated to acquire dynamic excitation data during vehicle operation, which will be used for analysis and application by the subsequent control module 3.

[0066] S213, determining the actual road surface type based on dynamic excitation data; In response, the dynamic excitation data acquired by the third sensing unit 7 is real-time feedback information during the vehicle's driving process, which can determine the vehicle's current driving state. The road surface type obtained by the control module 3 based on the dynamic excitation data is the actual road surface type of the current driving segment of the vehicle, i.e., the actual road surface type.

[0067] S214, depending on the actual road surface type, pre-adjust the support force of at least some of the support members.

[0068] Based on the description of the vehicle tailgate low-frequency road noise control system, the control module 3 can execute the corresponding adjustment scheme under specific road surface conditions to achieve pre-adjustment of the support force of the support member 11 and improve control efficiency.

[0069] By adopting this method, driving behavior perception can be introduced through the third sensing unit 7, thereby improving the initiative of the control strategy, effectively responding to sudden road impacts, and further reducing the vibration peak and transient noise of the tailgate 8.

[0070] This application also provides a method for controlling low-frequency road noise at the tailgate of a vehicle. Please refer to the following for details. Figure 8 , Figure 8 This is a schematic flowchart illustrating a low-frequency road noise control method for a vehicle tailgate, as shown in another exemplary embodiment of this application. This method is applicable to the aforementioned low-frequency road noise control system for a vehicle tailgate that is simultaneously equipped with a second sensing unit 6 and a third sensing unit 7, and includes at least steps S301 to S305, detailed below: S301, acquire vehicle speed information and tailgate status signal; The implementation methods and objectives of steps S301 and S101 are the same, and will not be repeated here.

[0071] S302, when the vehicle speed information is greater than the preset vehicle speed and the status signal is in the off state, the predicted road surface type is determined based on the road surface contour information in front of the vehicle obtained by the second sensing unit. The implementation methods and objectives of steps S302, 202, and 203 are the same, and will not be repeated here.

[0072] S303, based on the predicted road surface type, the support force of at least some of the supports is pre-adjusted for the first time; The road surface contour information acquired by the second sensing unit 6 is a predicted information about the road area within a certain distance in front of the vehicle. The predicted road surface type obtained by the control module 3 based on this road surface contour information has a high probability of occurrence. Therefore, based on this step, the corresponding support component 11 can be pre-adjusted in advance before entering the predicted road section. For example, when receiving prediction information that the predicted road surface type is an uneven or high-impact-risk road section, all or part of the airbags can be pre-inflated in advance, which can effectively improve the response speed and realize feedforward active control.

[0073] S304, Based on the dynamic excitation data of the vehicle during driving obtained by the third sensing unit, determine the actual road surface type; The dynamic excitation data acquired by the third sensing unit 7 is real-time feedback information during the vehicle's driving process, which can determine the vehicle's current driving state. Based on the timing of this step, when the vehicle enters the predicted road segment, the control module 3 can further analyze the road surface type based on the dynamic excitation data to obtain the corrected actual road surface type.

[0074] S305, depending on the actual road surface type, at least some of the support members undergo a second pre-adjustment of the support force.

[0075] Typically, the vehicle tailgate low-frequency road noise control method provided in the above embodiments requires further fine-tuning of the support member 11 based on the vibration response signal collected by the first sensing unit 2 after pre-adjustment. To address this, based on step S305, on the one hand, after entering the predicted road section, a more precise second pre-adjustment can be performed on the corresponding support member 11 according to the actual road surface type, ensuring effective support of the support member 11; on the other hand, when the actual road surface type is basically consistent with the predicted road surface type, the parameters of the second pre-adjustment should also be the same as or similar to the parameters of the first pre-adjustment. Therefore, the adjustment range of the second pre-adjustment can be effectively reduced, improving control efficiency.

[0076] Using this method, external environment perception and driving behavior perception can be introduced simultaneously through the second sensing unit 6 and the third sensing unit 7. This not only allows for pre-control of the support component 11, improving control foresight and achieving "pre-vibration control," thus shortening the system response lag time, but also enhances the initiative of the control strategy, effectively responding to sudden road impacts and further reducing the vibration peak and transient noise of the tailgate 8.

[0077] It should also be noted that the vehicle tailgate low-frequency road noise control method provided in the above embodiments and the vehicle tailgate low-frequency road noise control system provided in the above embodiments belong to the same concept. The specific way in which each unit, module and component performs operation has been described in detail in the system embodiments, and will not be repeated here.

[0078] It is understood that, in this application, unless otherwise expressly specified and limited, the terms "assembly," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0079] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified. The terms "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application.

[0080] The illustrative expressions of the terms used above do not necessarily refer to the same embodiments or examples. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of those different embodiments or examples, without contradiction.

[0081] Although embodiments of this application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can modify, substitute, and vary the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of this patent application.

Claims

1. A low-frequency road noise control system for a vehicle tailgate, characterized in that, include: A support structure is provided between the tailgate and the vehicle body to provide support for the tailgate after the tailgate is closed relative to the vehicle body; The first sensing unit is disposed on the tailgate and is used to collect the vibration response signal of the tailgate; wherein, The support structure includes multiple support members with adjustable support force, and each of the multiple support members is connected to a control module; the control module is connected to the first sensing unit, and the control module is configured to adjust the support force of the support members according to the vibration response signal.

2. The vehicle tailgate low-frequency road noise control system according to claim 1, characterized in that, The support member is configured as an element that generates a change in support force based on its own internal pressure regulation. The control module includes a pressure regulation unit, which is connected to the support member through a fluid channel and is configured to regulate the internal pressure of the support member.

3. The vehicle tailgate low-frequency road noise control system according to claim 2, characterized in that, The support component is an inflatable airbag, and the pressure control unit is an air source. The airbag is inflated and deflated via the air source to switch between an inflated state and a retracted state. The airbag is configured to provide elastic support with variable stiffness when inflated, and to return to a retracted state after deflation to allow the tailgate to open and close normally.

4. The vehicle tailgate low-frequency road noise control system according to claim 3, characterized in that, Each airbag is connected to a common air source through an independent fluid channel, and each fluid channel is equipped with a solenoid valve; the solenoid valve is controlled by the control module and is used to control the inflation, pressure holding and depressurization actions of the corresponding airbag.

5. The vehicle tailgate low-frequency road noise control system according to claim 1, characterized in that, The tailgate is connected to the vehicle body via hinges and a door lock, with the hinges and the door lock located on opposite sides of the tailgate. With the vertical central axis of the tailgate about the hinge side and the door lock side as the axis of symmetry, a plurality of the support members are symmetrically installed on the edge area of ​​the tailgate.

6. The vehicle tailgate low-frequency road noise control system according to claim 5, characterized in that, The support members are provided in four parts, two of which are symmetrically installed on the edge area of ​​the tailgate near the door lock, and the other two are symmetrically installed on the edge areas on both sides of the middle of the tailgate.

7. The vehicle tailgate low-frequency road noise control system according to any one of claims 1-6, characterized in that, The system also includes: The second sensing unit includes a forward-facing camera and / or lidar equipped in the vehicle's driver assistance system, used to acquire road surface contour information in front of the vehicle; the control module is connected to the second sensing unit, and the control module is configured to adjust the support force of the support member according to the road surface contour information.

8. The vehicle tailgate low-frequency road noise control system according to any one of claims 1-6, characterized in that, The system also includes: The third sensing unit includes an acceleration sensor on the shock absorber in the vehicle chassis system, used to acquire dynamic excitation data during vehicle operation; the control module is connected to the third sensing unit, and the control module is configured to adjust the support force of the support member according to the dynamic excitation data.

9. The vehicle tailgate low-frequency road noise control system according to claim 7, characterized in that, The system also includes: The third sensing unit includes an acceleration sensor on the shock absorber in the vehicle chassis system, used to acquire dynamic excitation data during vehicle operation; the control module is connected to the third sensing unit, and the control module is configured to adjust the support force of the support member according to the dynamic excitation data.

10. A method for controlling low-frequency road noise at a vehicle tailgate, applied to the low-frequency road noise control system for a vehicle tailgate as described in any one of claims 1-6, characterized in that, The method includes: Acquire vehicle speed information and tailgate status signals; When the vehicle speed information is greater than the preset vehicle speed and the status signal is in the off state, the vibration response signal collected by the first sensing unit is acquired; The supporting force of the support member is adjusted according to the vibration response signal.

11. A method for controlling low-frequency road noise at a vehicle tailgate, characterized in that, The method includes: Acquire vehicle speed information and tailgate status signals; When the vehicle speed information is greater than a preset vehicle speed and the status signal is in the off state, the road surface contour information in front of the vehicle is acquired by the second sensing unit as described in claim 7; a predicted road surface type is determined based on the road surface contour information; and the support force of at least some of the support members is pre-adjusted according to the predicted road surface type; or The third sensing unit as described in claim 8 acquires dynamic excitation data during vehicle operation; the actual road surface type is determined based on the dynamic excitation data; and the support force of at least a portion of the support members is pre-adjusted according to the actual road surface type.

12. A method for controlling low-frequency road noise at a vehicle tailgate, applied to the low-frequency road noise control system for a vehicle tailgate as described in claim 9, characterized in that, The method includes: Acquire vehicle speed information and tailgate status signals; When the vehicle speed information is greater than the preset vehicle speed and the status signal is in the off state, the predicted road surface type is determined based on the road surface contour information in front of the vehicle obtained by the second sensing unit. Based on the predicted road surface type, the support force of at least some of the support members is pre-adjusted for the first time. Based on the dynamic excitation data of the vehicle during driving obtained by the third sensing unit, the actual road surface type is determined. Based on the actual road surface type, at least some of the support members undergo a second pre-adjustment of the support force.

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