A method for adjusting the body of a vehicle in a static manner to simulate a braking attitude

Abstract

The application provides a vehicle body static adjustment method for simulating a vehicle braking posture, which comprises the following steps: obtaining basic data and establishing a measurement coordinate system after adjusting a target vehicle to a preset state; calculating a target height difference between a rear wheel arch height and a front wheel arch height in the preset state according to a preset vehicle body pitch angle increment; keeping the front wheel arch height equal to an initial front wheel arch height, lifting the rear wheel through a lifting device to adjust the vehicle body posture of the target vehicle, and monitoring the rear wheel arch height until the measured height difference between the rear wheel arch and the front wheel arch is equal to the target height difference; performing geometric verification and angle verification on the adjusted vehicle body posture to obtain verification results, and performing a second verification after the target vehicle verification results meet the requirements. The application precisely calibrates multiple key points through three coordinate systems, obtains basic data to form a vehicle adjustment reference, calculates the initial height of the gravity center based on the axle load, and realizes millimeter-level vehicle body lifting in combination with the theoretical value control.

Description

Technical Field

[0001] This application relates to the field of automotive testing technology, and in particular to a method for statically adjusting the vehicle body to simulate the braking posture of a vehicle. Background Technology

[0002] With the continuous advancement of urbanization in my country, the "mixed traffic of pedestrians and vehicles" scenario is becoming increasingly common in urban traffic environments. This has led to a significant increase in violations by vulnerable road users (VRUs, such as pedestrians and non-motorized vehicle riders), resulting in a substantial rise in the risk of traffic accidents. Against this backdrop, the development of intelligent vehicle safety has become a core research direction in the industry, with the construction of an evaluation system for VRU protection being particularly crucial. Currently, the safety performance of intelligent vehicles relies on the precise operation of various active safety systems, and the simulation and precise control of vehicle posture under dynamic conditions are fundamental prerequisites for ensuring the effectiveness of safety system testing. However, existing technologies lack static adjustment schemes for vehicle posture during braking, making it difficult to support the precise reproduction requirements of dynamic conditions in intelligent vehicle safety development. This has become a significant technical bottleneck restricting the improvement of the VRU protection evaluation system.

[0003] In intelligent vehicle active safety systems, the Automatic Emergency Braking (AEB) system is one of the core technologies for preventing VRU collision accidents, and the scientific nature of its performance verification system directly determines the safety protection effect of the vehicle in actual driving. Currently, mainstream AEB system testing schemes are all based on the static standard posture of the vehicle, assuming that the vehicle maintains its normal driving posture (such as fixed wheel arch height and center of gravity position) during the test, without considering the dynamic physical changes of the vehicle during actual braking. Due to the inertial forces of the vehicle during braking, the suspension system will undergo compressive deformation, resulting in a pitching phenomenon at the front of the vehicle (the front wheel arch height decreases, the rear wheel arch height relatively increases, and the body forms a certain tilt angle). This static posture-based testing system, while able to complete basic functional verification, cannot reproduce the vehicle posture characteristics under real braking conditions, resulting in a significant difference between the AEB system testing environment and actual application scenarios.

[0004] However, the technical deficiencies in existing AEB system testing frameworks directly lead to a dual dilemma for automakers: On the one hand, due to the lack of braking posture parameters, automakers cannot accurately assess the actual protection effect of existing AEB systems on VRUs under real dynamic conditions, potentially leading to the risk of "passing laboratory tests but failing in real-world applications." On the other hand, the lack of braking posture simulation schemes makes it difficult for automakers to optimize AEB system algorithms for changes in vehicle posture under dynamic conditions, hindering further improvements in system adaptability and reliability. Furthermore, existing technologies lack standardized methods for static adjustment of vehicle braking posture; the tuning process relies heavily on experience, resulting in low parameter measurement accuracy, poor posture restoration repeatability, and insufficient reliability of test data. This fails to provide a stable and accurate testing benchmark for the VRU protection evaluation system, severely hindering the in-depth development of intelligent vehicle safety. Summary of the Invention

[0005] This application provides a method for statically adjusting the vehicle body to simulate the braking posture of a vehicle, in order to solve the problem that there is no standardized method for statically adjusting the braking posture of a vehicle in the prior art. The vehicle adjustment process often relies on experience, which results in problems such as low accuracy of parameter measurement, poor repeatability of posture restoration, and insufficient reliability of test data.

[0006] This application provides a method for static adjustment of a vehicle body to simulate the braking posture of a vehicle, the method comprising: After adjusting the target vehicle to a preset state, basic data is acquired, and a measurement coordinate system is established based on the basic data; wherein, the basic data includes the initial height of the front wheel arch, the initial height of the rear wheel arch, the vehicle wheelbase, the front wheel axle load, and the vehicle curb weight; the preset state is the normal driving state of the target vehicle; Based on the preset vehicle pitch angle increment, calculate the target height difference between the rear wheel arch height and the front wheel arch height under the preset state; Keep the front wheel arch height equal to the initial front wheel arch height, lift the rear wheels using the lifting device to adjust the vehicle's body posture, and monitor the rear wheel arch height in real time until the measured height difference between the rear wheel arch and the front wheel arch equals the target height difference, and then lock the lifting device. The adjusted vehicle body posture is geometrically and angularly verified to obtain the verification results. After the target vehicle's verification results meet the standards, a second verification is conducted. After the second verification is completed, the adjustment of the target vehicle is finished.

[0007] In some possible implementations, after adjusting the target vehicle to a preset state, acquiring basic data, and establishing a measurement coordinate system based on the basic data, the process includes: Adjust the target vehicle by adjusting the hydraulic jacks on the side of the rear wheel and the auxiliary support of the front wheel, so that the initial height of the front wheel arch reaches the first preset height and the initial height of the rear wheel arch reaches the second preset height. When the target vehicle is adjusted to a preset state, a measurement coordinate system is established based on the vehicle coordinate system of the target vehicle; wherein, the X-axis points to the front of the vehicle, the Y-axis points to the left of the driver, the Z-axis is vertically upward, and Z=0 at the ground; The rigid point at the left front door latch was collected using a measurement coordinate system. Rigid point at the left rear door latch Arbitrary rigid point of the vehicle .

[0008] In some possible implementations, the target height difference between the rear wheel arch height and the front wheel arch height under a preset state is calculated based on a preset vehicle body pitch angle increment, including: Obtain the initial vehicle body angle and then obtain the target vehicle body angle based on the preset angle; The target height difference between the rear wheel arch height and the front wheel arch height under a preset state is calculated based on the target vehicle body angle and a first preset formula; wherein, the preset formula is: ; For the target height difference, The height of the rear wheel arch. The height of the front wheel arch. For preset angle, This is the initial vehicle height.

[0009] In some possible implementations, maintaining the front wheel arch height equal to the initial front wheel arch height and raising the rear wheels via a lifting device to adjust the vehicle's attitude includes: Slowly raise the rear wheel side hydraulic jacks and continuously measure the rear wheel arch height with a height gauge until the height difference between the rear wheel arch height and the front wheel arch height equals the target height difference. Then lock the rear wheel hydraulic jacks to prevent the vehicle body from shifting.

[0010] In some possible implementations, geometric and angular verification of the adjusted vehicle body posture includes: When the height difference between the rear wheel arch and the front wheel arch is equal to the target height difference, the actual lift of the front wheel arch and the actual lift of the rear wheel arch are calculated based on the current height of the rear wheel arch and the front wheel arch. The theoretical height of the center of gravity rise is calculated based on the actual lift of the front wheel arches and the actual lift of the rear wheel arches. The measured height of the center of gravity is calculated using the aforementioned coordinate system. The first verification result was obtained by verifying the theoretical and measured heights of the center of gravity.

[0011] In some possible implementations, geometric and angular verification of the adjusted vehicle body posture also includes: Obtain the coordinates of the target vehicle at the adjusted points P1 and P2, and determine the adjusted coordinates of the target vehicle at the adjusted points P1 and P2 as the first coordinate and the second coordinate. Perform Y-axis consistency verification based on the first and second coordinates; After performing Y-axis consistency verification, the target vehicle's P1 and P2 before adjustment are defined as the first straight line, and the target vehicle's P1 and P2 after adjustment are defined as the second straight line. The angle between the first line and the second line is calculated based on the vector dot product formula in the XOZ plane of the measurement coordinate system. The second verification result is obtained by verifying the included angle and the preset angle.

[0012] In some possible implementations, geometric and angular verification of the adjusted vehicle body posture also includes: After the first and second verification results meet the standards, the accuracy of the target vehicle's P3 point coordinates before adjustment is verified by comparing them with the first preset coordinates to obtain the third verification result.

[0013] In some possible implementations, the second verification after the target vehicle verification results meet the standards includes: After the third verification result meets the standard, the accuracy of the target vehicle at the adjusted P3 point coordinates is verified by comparing them with the second preset coordinates. Adjustments to the target vehicle were completed after the second verification.

[0014] In some possible implementations, after the third verification result meets the standard, the accuracy verification is performed by comparing the target vehicle's adjusted P3 point coordinates with the second preset coordinates, including: To obtain the theoretical elevation of the center of gravity; The difference between the target vehicle's adjusted P3 coordinates and the theoretical center of gravity rise height is used as the coordinates for the second verification. The accuracy of the second verification coordinates is verified by comparing them with the second preset coordinates.

[0015] In some possible implementations, the process before adjusting the target vehicle to a preset state includes: Wheel blocks are placed in front of and behind the front wheels of the vehicle. Mechanical jacks are used to fix the front wheels laterally, and adjustable hydraulic jacks are arranged on the side of the rear wheels for lifting.

[0016] As can be seen from the above, this application provides a method for statically adjusting the vehicle body to simulate the braking posture of a vehicle. This method includes adjusting the target vehicle to a preset state, acquiring basic data, and establishing a measurement coordinate system based on the basic data; calculating the target height difference between the rear wheel arch height and the front wheel arch height under the preset state according to a preset vehicle body pitch angle increment; maintaining the front wheel arch height equal to the initial front wheel arch height, raising the rear wheels using a lifting device to adjust the vehicle body posture of the target vehicle, and monitoring the rear wheel arch height in real time until the measured height difference between the rear wheel arch and the front wheel arch equals the target height difference, and then locking the lifting device; performing geometric and angular verification on the adjusted vehicle body posture to obtain verification results; performing a second verification after the target vehicle verification results meet the standards; and completing the adjustment of the target vehicle after the second verification. This application uses a three-coordinate system (vehicle body / ground / digital model) to accurately calibrate multiple key points, obtain initial wheel arch height, lock hook coordinates and center of gravity data, and form a shunting benchmark; calculates the initial height of the center of gravity based on axle load, and controls the hydraulic system to achieve millimeter-level vehicle body lifting by combining the theoretical target height difference, ensuring that the measured target height difference matches the target value.

[0017] This application compares the changes in center of gravity height before and after adjustment to verify the accuracy of theoretical calculations; it ensures that the vehicle body posture meets the tolerance of the digital model by detecting the included angle of the connecting lines at multiple points; and it triggers fine-tuning by using the deviation between the measured values ​​at fixed points and the virtual ground digital model to ensure consistency between the measured and actual values. A multi-person, multi-workstation, and multi-time period data acquisition mode is adopted to eliminate errors introduced by operational and temporal / spatial differences; and a multi-dimensional comparison system achieves a high degree of consistency in the vehicle shunting direction, with data repeatability meeting engineering reliability standards. Attached Figure Description

[0018] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of a method for statically adjusting the vehicle body to simulate the braking posture of a vehicle according to an embodiment of this application; Figure 2 This is a schematic diagram of the target vehicle before adjustment according to one embodiment of this application; Figure 3 This is a schematic diagram of the target vehicle after adjustment according to one embodiment of this application. Detailed Implementation

[0020] The embodiments described in the following examples do not represent all embodiments consistent with this application. They are merely examples of systems and methods consistent with some aspects of this application as detailed in the claims.

[0021] With the continuous advancement of urbanization in my country, the "mixed traffic of pedestrians and vehicles" scenario is becoming increasingly common in urban traffic environments. This has led to a significant increase in violations by vulnerable road users (VRUs, such as pedestrians and non-motorized vehicle riders), resulting in a substantial rise in the risk of traffic accidents. Against this backdrop, the development of intelligent vehicle safety has become a core research direction in the industry, with the construction of an evaluation system for VRU protection being particularly crucial. Currently, the safety performance of intelligent vehicles relies on the precise operation of various active safety systems, and the simulation and precise control of vehicle posture under dynamic conditions are fundamental prerequisites for ensuring the effectiveness of safety system testing. However, existing technologies lack static adjustment schemes for vehicle posture during braking, making it difficult to support the precise reproduction requirements of dynamic conditions in intelligent vehicle safety development. This has become a significant technical bottleneck restricting the improvement of the VRU protection evaluation system.

[0022] In intelligent vehicle active safety systems, the Automatic Emergency Braking (AEB) system is one of the core technologies for preventing VRU collision accidents, and the scientific nature of its performance verification system directly determines the safety protection effect of the vehicle in actual driving. Currently, mainstream AEB system testing schemes are all developed and designed based on the vehicle's "static standard posture," assuming that the vehicle maintains its normal driving posture (such as fixed wheel arch height and center of gravity position) during the test, without considering the dynamic physical changes of the vehicle during actual braking. Due to the inertial forces of the vehicle during braking, the suspension system will undergo compressive deformation, resulting in a "pitch phenomenon" at the front of the vehicle (the front wheel arch height decreases, the rear wheel arch height relatively increases, and the body forms a certain tilt angle). While this static posture-based testing system can complete basic functional verification, it cannot reproduce the vehicle posture characteristics under real braking conditions, resulting in a significant difference between the AEB system's testing environment and actual application scenarios.

[0023] However, the technical deficiencies in existing AEB system testing frameworks directly lead to a dual dilemma for automakers: On the one hand, due to the lack of braking posture parameters, automakers cannot accurately assess the actual protection effect of existing AEB systems on VRUs under real dynamic conditions, potentially leading to the risk of "passing laboratory tests but failing in real-world applications." On the other hand, the lack of braking posture simulation schemes makes it difficult for automakers to optimize AEB system algorithms for changes in vehicle posture under dynamic conditions, hindering further improvements in system adaptability and reliability. Furthermore, existing technologies lack standardized methods for static adjustment of vehicle braking posture; the tuning process relies heavily on experience, resulting in low parameter measurement accuracy, poor posture restoration repeatability, and insufficient reliability of test data. This fails to provide a stable and accurate testing benchmark for the VRU protection evaluation system, severely hindering the in-depth development of intelligent vehicle safety.

[0024] This application, through the core logic of "preset state calibration - target height difference calculation - rear wheel lift adjustment - multi-wheel verification," can accurately simulate the vehicle's posture during braking. It keeps the front wheel arches stationary as a baseline, and then uses a lifting device to selectively lift the rear wheels, ensuring the height difference between the rear and front wheel arches matches the target value corresponding to the preset pitch angle. This directly fills the technological gap in the industry for static simulation of dynamic braking posture, providing automakers with a key technical solution for accurately evaluating the actual protection effect of AEB systems and optimizing system performance under dynamic conditions.

[0025] In some embodiments, such as Figures 1 to 3 As shown, this application provides a method for static adjustment of a vehicle body to simulate vehicle braking posture, the method comprising: After adjusting the target vehicle to the preset state, basic data is acquired, and a measurement coordinate system is established based on the basic data. The basic data includes the initial height of the front wheel arches, the initial height of the rear wheel arches, the vehicle wheelbase, the front axle load, and the vehicle curb weight. The preset state is the normal driving state of the target vehicle, even if the initial height of the front wheel arches reaches the first preset height and the initial height of the rear wheel arches reaches the second preset height. The first and second preset heights are those under the normal driving posture specified in the standard and are provided by the manufacturer, with different heights corresponding to different vehicle models.

[0026] Based on the preset vehicle pitch angle increment, calculate the target height difference between the rear wheel arch height and the front wheel arch height under the preset state; Keep the front wheel arch height equal to the initial front wheel arch height, lift the rear wheels using the lifting device to adjust the vehicle's body posture, and monitor the rear wheel arch height in real time until the measured height difference between the rear wheel arch and the front wheel arch equals the target height difference, and then lock the lifting device. The adjusted vehicle body posture is geometrically and angularly verified to obtain the verification results. After the target vehicle's verification results meet the standards, a second verification is conducted. After the second verification is completed, the adjustment of the target vehicle is finished.

[0027] This application establishes a unified and controllable shunting benchmark by acquiring basic data such as the initial height of the front wheel arches, the initial height of the rear wheel arches, wheelbase, front axle load, and vehicle curb weight, combined with coordinate system measurements. This avoids errors caused by fuzzy benchmarks in traditional experience-based shunting and provides precise data support for subsequent attitude adjustments. Based on the preset vehicle pitch angle increment, the target height difference is calculated, transforming the abstract pitch attitude into a directly monitorable wheel arch height difference, thus quantifying the shunting target and avoiding human judgment bias. By keeping the front wheel arch height constant and adjusting the attitude solely by raising the rear wheels, coupled with real-time monitoring of the rear wheel arch height, the shunting process can be precisely controlled, ensuring that the final measured height difference matches the target value, significantly improving the accuracy of vehicle attitude adjustment. This application first confirms that the attitude meets the standard through geometric verification and angle verification, and then further verifies it through a second verification, forming a closed loop of first adjustment-first verification-re-verification, constructing a cross-validation error control network, effectively eliminating the limitations of single verification, ensuring the reliability and repeatability of test data, and meeting the strict requirements of engineering testing for data consistency.

[0028] In some embodiments, after adjusting the target vehicle to a preset state, acquiring basic data, and establishing a measurement coordinate system based on the basic data includes: Adjust the target vehicle by adjusting the hydraulic jacks on the side of the rear wheel and the auxiliary support of the front wheel, so that the initial height of the front wheel arch reaches the first preset height and the initial height of the rear wheel arch reaches the second preset height. When the target vehicle is adjusted to a preset state, a measurement coordinate system is established based on the vehicle coordinate system of the target vehicle; wherein, the X-axis points to the front of the vehicle, the Y-axis points to the left of the driver, the Z-axis is vertically upward, and Z=0 at the ground; The rigid point at the left front door latch was collected using a measurement coordinate system. Rigid point at the left rear door latch Arbitrary rigid point of the vehicle .

[0029] In some embodiments, calculating the target height difference between the rear wheel arch height and the front wheel arch height under a preset state, based on a preset vehicle body pitch angle increment, includes: Obtain the initial vehicle body angle and then obtain the target vehicle body angle based on the preset angle; The target height difference between the rear wheel arch height and the front wheel arch height under a preset state is calculated based on the target vehicle body angle and a first preset formula; wherein, the preset formula is: ; For the target height difference, The height of the rear wheel arch. The height of the front wheel arch. For the preset angle, This is the initial vehicle height.

[0030] In some embodiments, maintaining the front wheel arch height equal to the initial front wheel arch height and raising the rear wheels using a lifting device to adjust the vehicle's body posture includes: Slowly raise the rear wheel side hydraulic jacks and continuously measure the rear wheel arch height with a height gauge until the height difference between the rear wheel arch height and the front wheel arch height equals the target height difference. Then lock the rear wheel hydraulic jacks to prevent the vehicle body from shifting.

[0031] In some embodiments, geometric verification and angle verification of the adjusted vehicle body posture include: When the height difference between the rear wheel arch and the front wheel arch is equal to the target height difference, the actual lift of the front wheel arch and the actual lift of the rear wheel arch are calculated based on the current height of the rear wheel arch and the front wheel arch. The theoretical height of the center of gravity rise is calculated based on the actual lift of the front wheel arches and the actual lift of the rear wheel arches. The measured height of the center of gravity is calculated using the aforementioned coordinate system. The first verification result was obtained by verifying the theoretical and measured heights of the center of gravity.

[0032] In some embodiments, geometric and angular verification of the adjusted vehicle body posture further includes: The coordinates of the target vehicle at the adjusted points P1 and P2 are obtained, and Y-axis consistency verification is performed based on the first coordinates and the second coordinates; wherein the first coordinates and the second coordinates are the coordinates of the target vehicle at the adjusted points P1 and P2, respectively. After performing Y-axis consistency verification, the target vehicle's P1 and P2 before adjustment are defined as the first straight line, and the target vehicle's P1 and P2 after adjustment are defined as the second straight line. The angle between the first line and the second line is calculated based on the vector dot product formula in the XOZ plane of the measurement coordinate system. The second verification result is obtained by verifying the included angle and the preset angle.

[0033] In some embodiments, geometric and angular verification of the adjusted vehicle body posture further includes: After the first and second verification results meet the standards, the accuracy of the target vehicle's P3 point coordinates before adjustment is verified by comparing them with the first preset coordinates to obtain the third verification result.

[0034] In some embodiments, the second verification after the target vehicle verification result meets the standard includes: After the third verification result meets the standard, the accuracy of the target vehicle at the adjusted P3 point coordinates is verified by comparing them with the second preset coordinates. Adjustments to the target vehicle were completed after the second verification.

[0035] In some embodiments, after the third verification result meets the standard, the accuracy verification is performed by comparing the target vehicle's adjusted P3 point coordinates with the second preset coordinates, including: To obtain the theoretical elevation of the center of gravity; The difference between the target vehicle's adjusted P3 coordinates and the theoretical center of gravity rise height is used as the coordinates for the second verification. The accuracy of the second verification coordinates is verified by comparing them with the second preset coordinates.

[0036] In some embodiments, the process before adjusting the target vehicle to a preset state includes: Wheel blocks are placed in front of and behind the front wheels of the vehicle. Mechanical jacks are used to fix the front wheels laterally, and adjustable hydraulic jacks are arranged on the side of the rear wheels for lifting.

[0037] This application uses a three-coordinate system (vehicle / ground / digital model) collaborative calibration to accurately obtain the initial wheel arch height, locking hook rigid point coordinates (P1, P2, P3), and initial center of gravity height, establishing a controllable benchmark system for subsequent vehicle shunting and avoiding cascading errors caused by initial data deviations. Based on axle load and wheelbase parameters, the target height difference is derived, and millimeter-level adjustment of the rear wheel arch height is achieved through hydraulic jacks, while the front wheel arch height is monitored in real time to ensure the accuracy of vehicle posture adjustment. Through a three-dimensional closed-loop verification of center of gravity rise height verification, P1 / P2 angle verification, and digital model matching verification (the deviation between P3 point and the digital model meets the accuracy requirements after correction), a safety network of cross-checking is constructed to ensure that the vehicle posture after shunting is highly consistent with the actual braking posture, and the repeatability and reliability of the test data meet engineering standards.

[0038] This application requires only conventional lifting devices, height measuring tools, and coordinate system measuring equipment, eliminating the need to purchase specialized high-end equipment and effectively controlling test hardware costs. Through real-time monitoring and multi-round verification, deviations during vehicle shunting can be detected promptly, facilitating timely adjustments, reducing test interruptions due to shunting errors, and improving test efficiency. The method provided in this application can stably and accurately simulate vehicle braking posture, offering a crucial posture simulation tool for establishing a vulnerable road user (VRU) protection evaluation system that includes braking posture parameters. The reliable test data obtained through this method can more realistically reflect the AEB system's protection capability for VRUs under actual braking conditions.

[0039] Example This embodiment provides a method for statically adjusting the vehicle body to simulate the braking posture of a vehicle as follows.

[0040] Step 1: Vehicle initial condition adjustment and baseline measurement 1.1 Operational Objectives Adjust the vehicle to "normal state" and obtain the initial wheel arch height, lock hook coordinates, and initial center of gravity height to provide a benchmark for subsequent vehicle shunting.

[0041] 1.2 Specific operations 1. Vehicle securing: Place the vehicle on a level test bench, and place wheel stops at the front and rear of the front wheels (to ensure that the front wheels do not move or rise during shunting); place mechanical jacks on the sides of the front wheels for lateral fixation, and place adjustable hydraulic jacks on the sides of the rear wheels (for subsequent lifting).

[0042] 2. Initial fender height calibration: By adjusting the rear wheel side hydraulic jacks (no specific model is required, any jack suitable for the vehicle) and the front wheel auxiliary support, the front wheel arch height is adjusted to reach [the desired height]. The rear wheel arch height reaches Complete the "normal state" adjustment. and It refers to the normal driving posture specified in the standard, which is generally provided by the manufacturer and varies in height depending on the vehicle model.

[0043] 3. Coordinate measurement and recording: Three-coordinate reference verification: Verify the test reference coordinate system O-XYZ using a three-coordinate measuring machine. This coordinate system is aligned with the vehicle coordinate system, with the X-axis pointing forward of the vehicle, the Y-axis pointing to the driver's left, and the Z-axis pointing vertically upward. Furthermore, Z=0 at the ground level.

[0044] Initial latch coordinate measurement: Under normal vehicle driving posture, use a coordinate measuring machine to measure the rigid point at the left front door latch. Rigid point at the left rear door latch Arbitrary rigid point of the vehicle These three rigid points do not have fixed positions; they only need to be at the same point as the subsequent braking posture.

[0045] 4. Initial height measurement of center of gravity: According to the formula Where L is the distance from the center of the front wheel to the center of the rear wheel, and M is the vehicle's curb weight. This refers to the front axle load. Mark the projection point of the center of gravity C on the vehicle's longitudinal centerline (select a rigid point on the line connecting the wheel arches, and make a permanent mark on the side of the vehicle body); measure the initial Z-coordinate of this projection point using a coordinate measuring machine, and denote it as... (Initial height of center of gravity above the ground).

[0046] Step 2: Calculation of target height difference 2.1 Operational Objectives Based on the preset angle increment Δθ, the target height difference ΔH between the rear wheel arch and the front wheel arch is calculated and used as the core basis for shunting.

[0047] 2.2 Specific operations 1. Specify the preset test angle Δθ (enter according to the car manufacturer's requirements, such as Δθ = 2°).

[0048] 2. Derive the target height difference ΔH in three steps: ① Calculate the initial vehicle body angle: ; ② Calculate the target vehicle body angle: ; ③ Calculate the target height difference: ; 3. After shunting With this as the core objective, proceed to the next step of the shunting operation.

[0049] Step 3: Vehicle body lift adjustment and ΔH verification 3.1 Operational Objectives By adjusting the rear wheel arch height, ensure that the height difference between the rear and front wheel arches is equal to ΔH after vehicle adjustment, and keep the front wheel arch height as constant as possible. But there's no need to deliberately pursue it. The individual theoretical value.

[0050] 3.2 Specific operations 1. Keep the front wheels in the same position: Confirm that the wheel chocks under the front wheels have not moved and the front wheel arch height is unchanged. With the initial Consistent (can be monitored in real time using a height gauge).

[0051] 2. Adjust the rear wheel arch height: Slowly raise the hydraulic jacks on the side of the rear wheel, and continuously measure the height of the rear wheel arches with a height gauge. until the " ".

[0052] 3. Lock the jacks: After reaching the target height difference, lock the rear wheel hydraulic jacks to prevent the vehicle body from shifting.

[0053] Step 4: Verify the height of the center of gravity rise combined with the verification of the angle between P1 and P2. 4.1 Operational Objectives Dual-dimensional verification of vehicle body posture: ① The rising center of gravity conforms to the laws of rigid body mechanics; ② The change in the angle between the lines connecting P1 and P2 precisely matches Δθ.

[0054] 4.2 Specific Operation 1: Verification of Center of Gravity Rise Height (Based on Wheel Arch Rise Calculation) 1. Extracting the actual increase in wheel arch volume: Obtain the measured data from the shunting results in step 3: The actual increase in volume for the front wheel arches: (generally (because the front wheels remain stationary) The actual increase in volume for the rear wheel arches: ; 2. Calculate the theoretical height h of the center of gravity: According to the principle of rigid body moment equilibrium, the total mass of the vehicle The height of the center of gravity rise is determined by the proportion of the front and rear wheel arch rise to the axle load, as shown in the formula: ; 3. Actual height of the center of gravity as measured : After shunting, the Z coordinate of the projection point of the center of gravity C is remeasured using a coordinate measuring machine and recorded as follows: ; Calculate the actual volume: ; 4. Error verification: confirm" "Meets the requirements for test accuracy."

[0055] 4.3 Specific Operation 2: Verification of the angle between points P1 and P2 (comparison of the angle in the Xoz plane with the target Δθ) 1. Verification of consistency between coordinate records and the Y-axis: After re-measuring the car using a coordinate measuring machine , The complete coordinates, recording the X and Z coordinates (for vector calculations); 2. Verify Y-axis consistency: Ensure consistency before shunting: After shunting: Ensure that the line connecting P1 and P2 is within the XOZ plane.

[0056] 3. Define the line and extract the vector: Straight before shunting : Moved forward from P1 P2 before adjustment Determined, direction vector ,in , ; Straight line after shunting Adjusted by P1 After P2 adjustment Determined, direction vector ,in , .

[0057] 4. Calculation and The included angle α: Based on the dot product formula for vectors in the XOZ plane, the angle between two lines can be calculated directly (unaffected by changes in the X coordinate): ① Vector dot product: ; ② Vector magnitude: ; ③ Angle formula: .

[0058] 5. Verification by comparison with the target Δθ: It has been confirmed that "|α - Δθ target|" meets the experimental accuracy requirements.

[0059] Step 5: Model Matching Verification (Virtual Ground Correction) 5.1 First Verification: Comparison of measured P3 value with digital model z0 under normal conditions (benchmark calibration) 5.1.1 Operational Objectives Confirm that the vehicle's "normal initial state" is consistent with the company's initial state in the digital model, thus establishing a reliable benchmark for subsequent vehicle shunting verification.

[0060] 5.1.2 Specific operations 1. Prerequisite: The vehicle has completed step 1, "Normal Initial State Adjustment" (wheel arch height). , The target has been met; the consistency verification for P1 / P2 Y has passed.

[0061] 2. Obtaining the measured value of P3: Use a coordinate measuring machine to measure the Z-coordinate before adjustment of P3 in step 1. (Matching with digital model points).

[0062] Digital model comparison: confirm " "Meets the test accuracy requirements () (P3 normal state digital model value provided to enterprises).

[0063] 3. Anomaly Handling: If the error exceeds the tolerance, readjust the vehicle's initial attitude (e.g., fine-tune wheel arch height, calibrate the three-coordinate system) until the error meets the standard; the vehicle must not proceed to the shunting stage until the standard is met. It should be noted that at this stage, the vehicle is adjusted to the state corresponding to the parameters that were successfully verified in the first test.

[0064] 5.2 Second Verification: Comparison of P3 Correction Value after Shunting with Digital Model z1 (Virtual Ground Correction) 5.2.1 Operational Objectives Considering the overall lifting of the vehicle body after shunting (the virtual ground rises h relative to the "normal ground" in the digital model), the measured value of P3 is corrected to verify that the attitude after shunting is consistent with the state after shunting in the digital model.

[0065] 5.2.2 Specific operations Preliminary data preparation: Extract the theoretical ascent height h from step 4; Obtain P3 shunting post-model reference values ​​from the enterprise. .

[0066] P3 Measured value obtained after shunting: The Z coordinate of P3 after shunting was remeasured using a coordinate measuring machine and recorded as . (Ensure that the measurement points are completely consistent with those before shunting).

[0067] Virtual ground correction: Due to the overall vehicle body being raised by h after shunting (the "actual ground" is h higher than the "normal ground" in the digital model), the following corrections are made: The formula is modified as follows: ; Digital model comparison: confirm " "Meets the requirements for test accuracy."

[0068] Anomaly Handling: If the error exceeds the tolerance, recheck the accuracy of the h calculation (confirm that ΔHf and ΔHr are measured values) or To ensure measurement accuracy, a remeasurement should be performed after readjusting the vehicle if necessary.

[0069] It should be noted that after the first verification, the successful result of the first verification is recorded, and inflation-related tests are performed on the target vehicle. After the relevant tests, the angle of the target vehicle may be slightly deviated. At this time, the target vehicle is adjusted to the state corresponding to the parameters of the first successful verification, and then the second verification is performed. After the second verification, inflation-related tests are performed on the target vehicle again. After the relevant tests are completed, the adjustment of the target vehicle is completed.

[0070] Key reminder: You must complete the first "normal status verification" first. If the first verification fails, the train will be shunted and a second verification will be performed. If the first verification fails, shunting the train directly will cause all subsequent verifications to lose their benchmark, increasing the difficulty of investigation.

[0071] The specific values ​​in this embodiment are as follows: Normal driving posture: Front wheel arch height reached The rear wheel arch height reaches .

[0072] Wheelbase L = 2720 mm. Curb weight M = 1897 kg. Front axle load. Rear wheel axle load .

[0073] get Center of gravity .

[0074] With a preset angle increment Δθ = 1°, the target height difference ΔH between the rear wheel arch and the front wheel arch is calculated to be 62 mm.

[0075] Initial vehicle body angle: Target vehicle body angle: .

[0076] Target height difference: .

[0077] Braking posture: Front wheel arch height reached The rear wheel arch height reaches .

[0078] Center of gravity .

[0079] The theoretical rise height h = 36 mm, actual rise: . .

[0080] Based on the coordinate system and The included angle α = 0.947°.

[0081] |α-Δθtarget|=0.053°.

[0082] As can be seen from the above embodiments, this application provides a method for static adjustment of vehicle body to simulate vehicle braking posture. The method includes adjusting the target vehicle to a preset state, acquiring basic data, and establishing a measurement coordinate system based on the basic data; calculating the target height difference between the rear wheel arch height and the front wheel arch height in the preset state according to the preset vehicle body pitch angle increment; keeping the front wheel arch height equal to the initial height of the front wheel arch, raising the rear wheel through a lifting device to adjust the vehicle body posture of the target vehicle, and monitoring the rear wheel arch height in real time until the measured height difference between the rear wheel arch and the front wheel arch equals the target height difference, and then locking the lifting device; performing geometric verification and angle verification on the adjusted vehicle body posture to obtain verification results, and performing a second verification after the target vehicle verification results meet the standards, and completing the adjustment of the target vehicle after the second verification. This application uses a three-coordinate system (vehicle / ground / digital model) to accurately calibrate multiple key points, obtain initial wheel arch height, lock hook coordinates and center of gravity data, and form a shunting benchmark; calculates the initial height of the center of gravity based on axle load, and controls the hydraulic system to achieve millimeter-level vehicle body lifting in combination with the theoretical ΔH value, ensuring that the measured ΔH matches the target value.

[0083] Similar parts between the embodiments provided in this application can be referred to mutually. The specific implementation methods provided above are only a few examples under the overall concept of this application and do not constitute a limitation on the scope of protection of this application. For those skilled in the art, any other implementation methods extended from the solution of this application without creative effort shall fall within the scope of protection of this application.

Claims

1. A method for statically adjusting a vehicle body to simulate its braking posture, characterized in that, The method includes: After adjusting the target vehicle to a preset state, basic data is acquired, and a measurement coordinate system is established based on the basic data; wherein, the basic data includes the initial height of the front wheel arch, the initial height of the rear wheel arch, the vehicle wheelbase, the front wheel axle load, and the vehicle curb weight; the preset state is the normal driving state of the target vehicle; After adjusting the target vehicle to a preset state, acquiring basic data and establishing a measurement coordinate system based on the basic data includes: Adjust the target vehicle by adjusting the hydraulic jacks on the side of the rear wheel and the auxiliary support of the front wheel, so that the initial height of the front wheel arch reaches the first preset height and the initial height of the rear wheel arch reaches the second preset height. When the target vehicle is adjusted to a preset state, a measurement coordinate system is established based on the vehicle coordinate system of the target vehicle; wherein, the X-axis points to the front of the vehicle, the Y-axis points to the left of the driver, the Z-axis is vertically upward, and Z=0 at the ground; The rigid point at the left front door latch was collected using a measurement coordinate system. Rigid point at the left rear door latch Arbitrary rigid point of the vehicle ; Based on the preset vehicle pitch angle increment, calculate the target height difference between the rear wheel arch height and the front wheel arch height under the preset state, including: Obtain the initial vehicle body angle and then obtain the target vehicle body angle based on the preset angle; The target height difference between the rear wheel arch height and the front wheel arch height under a preset state is calculated based on the target vehicle body angle and a first preset formula; wherein, the preset formula... ; For the target height difference, Rear wheel arch height The height of the front wheel arch. The distance from the center of the front wheel to the center of the rear wheel. For preset angle, This is the initial vehicle height; Keep the front wheel arch height equal to the initial front wheel arch height, lift the rear wheels using the lifting device to adjust the vehicle's body posture, and monitor the rear wheel arch height in real time until the measured height difference between the rear wheel arch and the front wheel arch equals the target height difference, and then lock the lifting device. The adjusted vehicle body posture is geometrically and angularly verified to obtain the verification results. After the target vehicle's verification results meet the standards, a second verification is conducted. After the second verification is completed, the adjustment of the target vehicle is finished.

2. The method for static adjustment of vehicle body to simulate vehicle braking posture according to claim 1, characterized in that, Maintaining the front wheel arch height equal to the initial front wheel arch height, and adjusting the vehicle's attitude by raising the rear wheels using a lifting device includes: Slowly raise the rear wheel side hydraulic jacks and continuously measure the rear wheel arch height with a height gauge until the height difference between the rear wheel arch height and the front wheel arch height equals the target height difference. Then lock the rear wheel hydraulic jacks to prevent the vehicle body from shifting.

3. The method for static adjustment of vehicle body to simulate vehicle braking posture according to claim 2, characterized in that, The geometric and angular verification of the adjusted vehicle body posture includes: When the height difference between the rear wheel arch and the front wheel arch is equal to the target height difference, the actual lift of the front wheel arch and the actual lift of the rear wheel arch are calculated based on the current height of the rear wheel arch and the front wheel arch. The theoretical center of gravity rise is calculated based on the actual lift of the front and rear wheel arches. The measured height of the center of gravity is calculated using the aforementioned coordinate system. The first verification result was obtained by verifying the theoretical and measured heights of the center of gravity.

4. The method for static adjustment of vehicle body to simulate vehicle braking posture according to claim 3, characterized in that, The geometric and angular verification of the adjusted vehicle body posture also includes: Obtain the adjusted coordinates of the target vehicle at points P1 and P2, and determine the adjusted coordinates of points P1 and P2 as the first coordinate and the second coordinate; Perform Y-axis consistency verification based on the first and second coordinates; After performing Y-axis consistency verification, the target vehicle's P1 and P2 before adjustment are defined as the first straight line, and the target vehicle's P1 and P2 after adjustment are defined as the second straight line. The angle between the first line and the second line is calculated based on the vector dot product formula in the XOZ plane of the measurement coordinate system; The second verification result is obtained by verifying the included angle and the preset angle.

5. The method for static adjustment of vehicle body to simulate vehicle braking posture according to claim 4, characterized in that, The geometric and angular verification of the adjusted vehicle body posture also includes: After the first and second verification results meet the standards, the accuracy of the target vehicle's P3 point coordinates before adjustment is verified by comparing them with the first preset coordinates to obtain the third verification result.

6. The method for static adjustment of vehicle body to simulate vehicle braking posture according to claim 5, characterized in that, After the target vehicle passes the initial verification, a second verification is conducted, including: After the third verification result meets the standard, the accuracy of the target vehicle at the adjusted P3 point coordinates is verified by comparing them with the second preset coordinates. Adjustments to the target vehicle were completed after the second verification.

7. The method for static adjustment of vehicle body to simulate vehicle braking posture according to claim 6, characterized in that, After the third verification result meets the standard, the accuracy verification is performed by comparing the target vehicle's adjusted P3 point coordinates with the second preset coordinates, including: To obtain the theoretical elevation of the center of gravity; The difference between the target vehicle's adjusted P3 coordinates and the theoretical center of gravity rise height is used as the coordinates for the second verification. The accuracy of the second verification coordinates is verified by comparing them with the second preset coordinates.

8. The method for static adjustment of vehicle body to simulate vehicle braking posture according to claim 1, characterized in that, Before adjusting the target vehicle to the preset state, the following steps are included: Wheel blocks are placed in front of and behind the front wheels of the vehicle. Mechanical jacks are used to fix the front wheels laterally, and adjustable hydraulic jacks are arranged on the side of the rear wheels for lifting.

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