Commercial vehicle tailgate partition independent deflection control device and method for crosswind working condition

Abstract

The application is suitable for the technical field of vehicle aerodynamic control, and provides a commercial vehicle tailgate partition independent deflection control device and method facing side wind conditions.The device comprises a three-part tailgate assembly, an independently arranged execution unit, a wind speed and direction sensor, a vehicle state sensing module and an electronic control unit.In the offline stage, an aerodynamic response offline mapping model is constructed through CFD simulation and Gaussian process regression, and an offline prediction table is generated.In the online stage, according to the real-time vehicle speed and side wind yaw angle, the optimal tailgate angle instruction for reducing resistance is output under the condition of meeting the lateral force safety threshold, and each tailgate is independently driven to execute.The application can actively adjust the posture of each tailgate according to the side wind, continuously reduce the aerodynamic resistance while ensuring the stability of the side wind, and has the advantages of fast decision-making, strong robustness and obvious oil-saving effect.

Description

Technical Field

[0001] This invention belongs to the field of vehicle aerodynamic control technology, and particularly relates to a commercial vehicle tailgate zoned independent deflection control device and method for crosswind conditions. Background Technology

[0002] When heavy-duty commercial vehicles cruise at high speeds, their air resistance mainly originates from the base pressure difference and wake separation in the rear area. To reduce fuel consumption, it is common engineering practice to install fixed or simple synchronously opening and closing exhaust tailgates at the rear of the vehicle. Studies have shown that under ideal conditions with no crosswinds (zero yaw), optimizing the tailgate angle can effectively reduce the rear vortex area and lower the drag coefficient.

[0003] However, commercial vehicles often encounter crosswind interference during actual operation, especially in scenarios such as cross-sea bridges, tunnel entrances and exits, and overtaking / passing. Crosswinds generate an additional lateral force and yaw moment, causing the vehicle to yaw, deviate from its lane, and even lead to instability risks. Existing rear aerodynamic devices have the following technical shortcomings:

[0004] Single objective and lack of coordination: Most designs take "drag reduction" as the only or primary objective, and their optimal angle may actually aggravate lateral aerodynamic forces and worsen the vehicle's crosswind stability under crosswind conditions.

[0005] The structure is rigid and cannot be adjusted in sections: Most existing devices are fixed angles or symmetrical linkages, and cannot independently adjust the angle of the left and right tail plates according to the direction of crosswind (such as wind coming from the left or right) in order to actively generate an additional aerodynamic torque to resist crosswind.

[0006] The control strategies are crude and lack robustness: some adjustable schemes use continuous adjustment, but fail to consider the noise and pulsation characteristics of actual wind signals, which can easily lead to frequent actuator operation, system jitter, and reduced lifespan. Moreover, their control algorithms are mostly based on simple rules or complex online calculations, making it difficult to balance real-time performance and optimality.

[0007] Therefore, there is an urgent need for an active tailgate system and method for commercial vehicles that can simultaneously achieve the dual goals of crosswind stability and drag reduction and energy saving under crosswind conditions, and has strong control robustness. Summary of the Invention

[0008] The purpose of this invention is to provide a commercial vehicle tailgate zoned independent deflection control device and method for crosswind conditions, aiming to solve the problems mentioned in the background art.

[0009] The present invention is implemented as follows: a commercial vehicle tailgate independent deflection control device for crosswind conditions, comprising:

[0010] The three-section tailgate assembly is fixed to the rear of the commercial vehicle and includes an upper tailgate, a left tailgate and a right tailgate. Each tailgate is connected to the vehicle body by an independent hinge.

[0011] An execution unit is provided at the rear of the commercial vehicle, and the upper tailgate, left tailgate and right tailgate are each connected to an independent execution unit for driving each tailgate to rotate independently around its hinge axis.

[0012] Wind speed and direction sensors are used to acquire relative flow information in real time during vehicle operation;

[0013] The vehicle status perception module is used to obtain the vehicle's longitudinal speed in real time.

[0014] The electronic control unit (ECU) is communicatively connected to the wind speed and direction sensors, the vehicle status perception module, and the execution unit. The ECU contains a pre-established offline aerodynamic response mapping model, which takes vehicle speed and crosswind yaw angle as inputs and the combination of three tailgate angles as variables. The ECU is configured to: calculate the real-time crosswind yaw angle based on relative incoming flow information and vehicle longitudinal speed; solve for the optimal tailgate angle combination that minimizes overall vehicle air resistance based on the offline aerodynamic response mapping model, while satisfying preset vehicle crosswind stability constraints; and control each execution unit to drive each tailgate to the optimal tailgate angle combination.

[0015] In a further technical solution, each of the aforementioned execution units adopts a hydraulic cylinder, a mounting bracket, and a hinged connection structure. The cylinder body end of the hydraulic cylinder is mounted on the rear frame or reinforcing beam of the vehicle body through a first hinge point, and the piston rod end is connected to the connecting seat on the corresponding tail plate through a second hinge point. The axis of the hydraulic cylinder is arranged at an angle relative to the hinge line of the tail plate.

[0016] In a further technical solution, the execution units of the left and right tailplates are respectively arranged at the left and right side reinforcement structures at the rear of the vehicle body and are hinged to the connecting seats on the left and right tailplates to form a symmetrical force path.

[0017] Another objective of this invention is to provide a method for independent deflection control of the tailgate of a commercial vehicle under crosswind conditions, based on the aforementioned device, comprising the following steps:

[0018] Step 1: Offline modeling and training;

[0019] Using vehicle speed, crosswind yaw angle, and three-section tailplate angle as input variables, and drag and lateral force as output indicators, a training dataset is obtained through simulation to construct an offline aerodynamic response mapping model.

[0020] Step 2: Obtain online wind information;

[0021] The relative incoming flow information is obtained by wind speed and direction sensors and fused with vehicle speed information to calculate the real-time environmental incoming wind speed and crosswind yaw angle.

[0022] Step 3: Real-time angle calculation and drive control;

[0023] Based on real-time vehicle speed and real-time crosswind yaw angle, the aerodynamic response offline mapping model is invoked. Under the premise of meeting the lateral force safety threshold, the optimal tailgate angle combination that minimizes the overall vehicle air resistance is solved, and each tailgate is driven to execute the optimal tailgate angle combination.

[0024] A further technical solution is that, in step 2, the formula for calculating the real-time crosswind yaw angle is as follows:

[0025] (1)

[0026] in, For real-time crosswind yaw angle, This is the four-quadrant arctangent function, used to calculate the yaw angle of the composite incoming flow relative to the longitudinal direction of the vehicle. For a moment The velocity component of the composite flow in the longitudinal direction of the vehicle. For a moment The velocity component of the synthesized flow in the lateral direction of the vehicle;

[0027] At the same time, Filtering is performed, and outlier rejection and signal validity determination logic are set. When the sensor fails or the data is abnormal, it enters the degradation mode and outputs a conservative safety tailgate angle.

[0028] A further technical solution, in step 3, is as follows: The optimal tailplate angle combination is solved as follows:

[0029] (2)

[0030] in, For a moment Three-zone tailgate angle combination The target deflection angle for the upper tailplate. The target deflection angle for the left tailplate. The target deflection angle for the right tailplate;

[0031] Electronic control unit in feasible set The optimal tailplate angle combination is solved internally, with the following optimization objective and constraints:

[0032] (3)

[0033] in, To find the tailplate angle combination that minimizes the predicted drag while satisfying the constraints, Candidate variables for the tailplate angle in the three zones. For real-time vehicle speed, In order to be in , and Predicted resistance values ​​under the given conditions In order to be in , and Predicted lateral aerodynamic forces of the vehicle under the given conditions. for The maximum lateral force threshold that the vehicle is allowed to withstand.

[0034] Further technical solutions also include:

[0035] Step 4: Decision stabilization;

[0036] In the tailplate angle update logic, a hysteresis interval and dwell time mechanism are introduced. An entry threshold and an exit threshold are set for the incoming wind speed and crosswind yaw angle to form a hysteresis band. A minimum dwell time and an update confirmation time are also set. The tailplate angle update command is only allowed when the incoming wind speed or crosswind yaw angle exceeds the entry threshold and the triggering condition is continuously met, and the time since the last update is greater than the minimum dwell time.

[0037] A further technical solution is that, in step 4, the update rule for the tailplate angle command is as follows:

[0038] When both the real-time incoming wind speed and the crosswind yaw angle are below the exit threshold, maintain the current angle or return to the preset safe angle.

[0039] When the real-time incoming wind speed or crosswind yaw angle exceeds the entry threshold and the duration is greater than the update confirmation time, and the time since the last update is greater than the minimum dwell time, the new optimal tailplate angle combination is updated.

[0040] In all other cases, the existing angle command remains unchanged.

[0041] The commercial vehicle tailgate independent deflection control device and method for crosswind conditions provided in this invention have the following beneficial effects:

[0042] (1) Multi-objective collaborative optimization: Through offline precise modeling and online constraint solving, the dual objectives of continuously pursuing the optimal drag reduction effect under the premise of ensuring crosswind stability were realized for the first time in tail plate control.

[0043] (2) Independent zones, active crosswind resistance: Each tailplate can be adjusted independently, and can generate asymmetrical aerodynamic configuration according to the crosswind direction, actively generating yaw moment to resist crosswind, which is fundamentally superior to traditional symmetrical or fixed tailplates.

[0044] (3) Fast decision-making and strong real-time performance: The “offline modeling + online table lookup” architecture is adopted to transform complex nonlinear optimization problems into millisecond-level table lookup and logical judgment, with low computational load and fully compatible with automotive-grade ECUs.

[0045] (4) Robust and reliable: The unique hysteresis + dwell time anti-jitter logic effectively filters out noise and gust interference from the actual wind field, greatly improving the lifespan of the actuator and the stability of the system. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating the construction process of an offline aerodynamic response mapping model.

[0047] Figure 2 The decision-making and control process of the commercial vehicle tailgate independent deflection control method for crosswind conditions provided in the embodiments of the present invention;

[0048] Figure 3 The diagram shows the structure of the three-zone tailgate assembly and the angle diagram of the three-zone tailgate in the crosswind independent deflection control device for commercial vehicles provided in this embodiment of the invention (where a is the structure of the three-zone tailgate assembly and b is the angle diagram of the three-zone tailgate).

[0049] Figure 4 A schematic diagram of the overall vehicle layout of a commercial vehicle tailgate zoned independent deflection control device for crosswind conditions, provided in an embodiment of the present invention.

[0050] Figure 5 This is a schematic diagram of the execution unit in the commercial vehicle tailgate independent deflection control device for crosswind conditions provided in an embodiment of the present invention.

[0051] In the attached diagram: Upper tailplate 1; Left tailplate 2; Right tailplate 3; Actuator 4; Wind speed and direction sensor 5; Electronic control unit 6. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0053] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0054] like Figure 3a, Figure 4 and Figure 5 As shown, a commercial vehicle tailgate independent deflection control device for crosswind conditions provided in one embodiment of the present invention includes:

[0055] The three-section tailgate assembly is fixed to the rear of the commercial vehicle and includes an upper tailgate 1, a left tailgate 2 and a right tailgate 3. Each tailgate is connected to the vehicle body by an independent hinge.

[0056] The execution unit 4 is located at the rear of the commercial vehicle, and the upper tail plate 1, left tail plate 2 and right tail plate 3 are each connected to an independent execution unit 4 to drive each tail plate to rotate independently around its hinge axis to achieve angular deflection.

[0057] Wind speed and direction sensor 5 is used to acquire relative flow information in real time during vehicle operation;

[0058] The vehicle status perception module is used to obtain the vehicle's longitudinal speed in real time.

[0059] The electronic control unit 6 is communicatively connected to the wind speed and direction sensor 5, the vehicle status perception module, and the execution unit 4, respectively.

[0060] The electronic control unit 6 contains a pre-established offline aerodynamic response mapping model. This model takes vehicle speed and crosswind yaw angle as inputs and the combination of three tailgate angles as variables. The electronic control unit 6 is configured to: calculate the real-time crosswind yaw angle based on the relative incoming flow information and the vehicle's longitudinal speed; solve for the optimal tailgate angle combination that minimizes the vehicle's air resistance based on the offline aerodynamic response mapping model, while satisfying preset vehicle crosswind stability constraints; and control each execution unit 4 to drive each tailgate to the optimal tailgate angle combination.

[0061] In a preferred embodiment of the present invention, each execution unit 4 employs a hydraulic cylinder, a mounting bracket, and a hinged connection structure. The cylinder body end of the hydraulic cylinder is mounted on the rear frame or reinforcing beam of the vehicle body through a first hinge point, and the piston rod end is connected to the connecting seat on the corresponding tailplate through a second hinge point. The axis of the hydraulic cylinder is arranged at an angle relative to the hinge line of the tailplate. The extension and retraction of the hydraulic cylinder generates an opening and closing torque at the hinge, driving the tailplate to rotate around the hinge axis to achieve angle adjustment. The execution units 4 of the left tailplate 2 and the right tailplate 3 are respectively arranged at the left and right reinforcing structures of the rear of the vehicle body and hinged to the connecting seats on the left tailplate 2 and the right tailplate 3, forming a symmetrical force path to reduce off-center load and torsion and improve structural rigidity and durability.

[0062] like Figure 1 and Figure 2As shown, another embodiment of the present invention provides a method for independent deflection control of the tailgate of a commercial vehicle under crosswind conditions, based on the above-mentioned device, including the following steps:

[0063] Step 1: Offline modeling and training;

[0064] The offline phase determines the input and output variables, with the input variables including at least the vehicle speed. Crosswind yaw angle And the three-section tailgate angle (upper tailgate angle) , left tailgate angle and right tailgate angle For details, please see Figure 3 (As shown in b), the output indicators should include at least resistance. With lateral force If necessary, introduce yaw moment. As a stability evaluation metric, optimized Latin square sampling was used to generate a sample set within the variable range, ensuring that the samples covered the high-speed cruise speed range, the typical crosswind yaw angle range, and the feasible range of tailplate angles in the three zones. After wind tunnel testing to verify the simulation model, extensive CFD simulations were performed on the sample points to obtain data. and The model is trained to obtain a training dataset. A Gaussian process regression model is constructed based on this dataset. The correlation between input variables is calculated using a kernel function, and hyperparameters are determined through maximum likelihood estimation, resulting in an offline mapping model from input variables to aerodynamic response. After training, the model is sampled at discrete points and converted into an offline prediction table of parameters for real-time use by the electronic control unit 6.

[0065] Step 2: Obtain online wind information;

[0066] During the online phase, relative incoming flow information is acquired through the vehicle's onboard wind speed and direction sensor 5, and fused with the vehicle's speed information to obtain the time. The ambient incoming wind speed and crosswind yaw angle are shown. A schematic diagram of the wind speed sensor and other module layout is provided. Figure 4 The electronic control unit 6 reads the composite incoming flow component first obtained in the vehicle coordinate system. and ,in, For a moment The velocity component of the composite flow in the longitudinal direction of the vehicle. For a moment The velocity component of the composite incoming flow in the lateral direction of the vehicle; the yaw angle is estimated as follows:

[0067] (1)

[0068] in, For real-time crosswind yaw angle, It is a four-quadrant arctangent function used to calculate the yaw angle of the composite incoming flow relative to the longitudinal direction of the vehicle.

[0069] To suppress noise and short-term pulsation, Filtering is performed, and outlier rejection and signal validity determination logic are set. When the sensor fails or the data is abnormal, it enters the degradation mode and outputs a conservative safety tailgate angle.

[0070] Step 3: Real-time angle calculation and drive control;

[0071] The controller adjusts according to the real-time vehicle speed. With real-time crosswind yaw angle The offline prediction table generated by the offline aerodynamic response mapping model is invoked to quickly predict aerodynamic responses such as drag and lateral force under different tailplate angle combinations. The control objective is to minimize drag while meeting the lateral force safety threshold. The electronic control unit 6 solves for the optimal tailplate angle combination within the feasible set of three-zone tailplate angles and outputs the target tailplate angles for each zone. Let the decision variables for the three-zone tailplate angles be:

[0072] (2)

[0073] in, For a moment Three-zone tailgate angle combination The target deflection angle for the upper tailplate. The target deflection angle for the left tailplate. The target deflection angle is the right tailplate.

[0074] Electronic control unit 6 in feasible set The optimal tailplate angle combination is solved internally, with the following optimization objective and constraints:

[0075] (3)

[0076] in, To find the tailplate angle combination that minimizes the predicted drag while satisfying the constraints, Candidate variables for the tailplate angle in the three zones. In order to be in , and Predicted resistance values ​​under the given conditions In order to be in , and Predicted lateral force values ​​for vehicles under the given conditions. for The maximum lateral force threshold that the vehicle is allowed to withstand.

[0077] The electronic control unit 6 receives the target angle and combines it with angle feedback to perform closed-loop control. The angle is achieved through the execution unit 4. At the same time, angle limits, action rate limits and fault protection are set to ensure smooth operation and no structural impact under sudden crosswind conditions.

[0078] Step 4: Decision stabilization;

[0079] To avoid frequent tailplate adjustments due to small fluctuations in incoming wind speed and crosswind yaw angle, which could lead to mechanical wear and control oscillations, a hysteresis interval and dwell time mechanism is introduced into the angle update logic. For incoming wind speed... Yaw angle with crosswind Set entry and exit thresholds respectively to form a hysteresis band. and When within the hysteresis band or below the entry threshold, angle updates are not triggered; the current command is maintained or the angle slowly recedes to a conservative level. or Angle commands are only allowed to be updated when the entry threshold is exceeded and the triggering conditions are continuously met. A minimum dwell time is also set. With update confirmation time The next update is only executed after the minimum dwell time has elapsed since the previous action was completed and the new operating condition continues to exceed the update confirmation time, thus ensuring that actions are taken only when necessary and not when not. (Regarding the real-time incoming wind speed...) and When both are below the exit threshold, maintain the current angle or fall back to a safe angle; when or Exceeding the entry threshold and the duration is greater than And the time since the last update is greater than In the case of a specific event, the tailplate angle is updated to the new optimal combination; otherwise, the existing angle command remains unchanged. The update rule can be expressed as:

[0080] (4)

[0081] in, This is the optimal tailplate angle combination obtained through real-time calculation; Preset safety angle combinations; The synchronization command is generated when the last tailboard update command is allowed, and the update conditions are met and the update is executed. ; The cumulative duration for which the triggering condition is met consecutively; and These are the crosswind yaw angle entry threshold and exit threshold, respectively; and These are the inflow velocity entry threshold and exit threshold, respectively; The tailplate angle command from the previous control cycle; To control the cycle, by combining constraints on the hysteresis band and dwell time, in scenarios with frequent changes in crosswind disturbances, ineffective actions can be significantly reduced. At the same time, when the crosswind significantly intensifies or the crosswind yaw angle changes significantly, the tailplate angle can be adjusted in a timely manner to meet the lateral force safety threshold and reduce drag, thus achieving a synergy between stability and safety and energy saving and drag reduction.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for independent deflection control of the tailgate of a commercial vehicle under crosswind conditions, characterized in that, A commercial vehicle tailgate independent deflection control device for crosswind conditions, the device comprising: The three-section tailgate assembly is fixed to the rear of the commercial vehicle and includes an upper tailgate, a left tailgate and a right tailgate. Each tailgate is connected to the vehicle body by an independent hinge. An execution unit is provided at the rear of the commercial vehicle, and the upper tailgate, left tailgate and right tailgate are each connected to an independent execution unit for driving each tailgate to rotate independently around its hinge axis. Wind speed and direction sensors are used to acquire relative flow information in real time during vehicle operation; The vehicle status perception module is used to obtain the vehicle's longitudinal speed in real time. The electronic control unit (ECU) is communicatively connected to the wind speed and direction sensors, the vehicle status perception module, and the execution unit. The ECU contains a pre-established offline aerodynamic response mapping model, which takes vehicle speed and crosswind yaw angle as inputs and the combination of three tailgate angles as variables. The ECU is configured to: calculate the real-time crosswind yaw angle based on relative incoming flow information and vehicle longitudinal speed; solve for the optimal tailgate angle combination that minimizes overall vehicle air resistance based on the offline aerodynamic response mapping model, while satisfying preset vehicle crosswind stability constraints; and control each execution unit to drive each tailgate to the optimal tailgate angle combination. The method includes the following steps: Step 1: Offline modeling and training; Using vehicle speed, crosswind yaw angle, and three-section tailplate angle as input variables, and drag and lateral force as output indicators, a training dataset is obtained through simulation to construct an offline aerodynamic response mapping model. Step 2: Obtain online wind information; The relative incoming flow information is obtained by wind speed and direction sensors and fused with vehicle speed information to calculate the real-time environmental incoming wind speed and crosswind yaw angle. Step 3: Real-time angle calculation and drive control; Based on the real-time vehicle speed and real-time crosswind yaw angle, the aerodynamic response offline mapping model is invoked. Under the premise of meeting the lateral force safety threshold, the optimal tailgate angle combination that minimizes the air resistance of the whole vehicle is solved, and each tailgate is driven to execute the optimal tailgate angle combination. In step 2, the formula for calculating the real-time crosswind yaw angle is as follows: （1） in, For real-time crosswind yaw angle, This is the four-quadrant arctangent function, used to calculate the yaw angle of the composite incoming flow relative to the longitudinal direction of the vehicle. For a moment The velocity component of the composite flow in the longitudinal direction of the vehicle. For a moment The velocity component of the synthesized flow in the lateral direction of the vehicle; At the same time, Filtering is performed, and outlier rejection and signal validity determination logic are set. When the sensor fails or the data is abnormal, it enters the degradation mode and outputs a conservative safety tailgate angle. In step 3, the optimal tailplate angle combination is solved as follows: （2） in, For a moment Three-zone tailgate angle combination The target deflection angle for the upper tailplate. The target deflection angle for the left tailplate. The target deflection angle for the right tailplate; Electronic control unit in feasible set The optimal tailplate angle combination is solved internally, with the following optimization objective and constraints: （3） in, To find the tailplate angle combination that minimizes the predicted drag while satisfying the constraints, Candidate variables for the tailplate angle in the three zones. For real-time vehicle speed, In order to be in , and Predicted resistance values ​​under the given conditions In order to be in , and Predicted lateral aerodynamic forces of the vehicle under the given conditions. for The maximum lateral force threshold that the vehicle is allowed to withstand.

2. The commercial vehicle tailgate independent deflection control method for crosswind conditions according to claim 1, characterized in that, Also includes: Step 4: Decision stabilization; In the tailplate angle update logic, a hysteresis interval and dwell time mechanism are introduced. An entry threshold and an exit threshold are set for the incoming wind speed and crosswind yaw angle to form a hysteresis band. A minimum dwell time and an update confirmation time are also set. The tailplate angle update command is only allowed when the incoming wind speed or crosswind yaw angle exceeds the entry threshold and the triggering condition is continuously met, and the time since the last update is greater than the minimum dwell time.

3. The commercial vehicle tailgate independent deflection control method for crosswind conditions according to claim 2, characterized in that, In step 4, the update rule for the tailplate angle command is as follows: When both the real-time incoming wind speed and the crosswind yaw angle are below the exit threshold, maintain the current angle or return to the preset safe angle. When the real-time incoming wind speed or crosswind yaw angle exceeds the entry threshold and the duration is greater than the update confirmation time, and the time since the last update is greater than the minimum dwell time, the new optimal tailplate angle combination is updated. In all other cases, the existing angle command remains unchanged.

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