A vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling

Abstract

The application relates to a vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling, which can effectively improve vehicle dynamics simulation precision and reduce the error between simulation and test. The method comprises the following steps: establishing a vehicle multi-rigid-body dynamics model without a road model and a tire model; establishing a vehicle rigid-flexible coupling dynamics model; establishing a virtual test bench with three-direction displacement input function; collecting shaft head and vehicle frame relative displacement data in actual road working conditions; and vehicle dynamics simulation and model calibration. The application comprehensively uses rigid-flexible coupling dynamics principles and finite element theory to establish a vehicle rigid-flexible coupling dynamics model based on shaft coupling, solves the problem of large error of the existing vehicle dynamics modeling method, and has high applicability and operability, and the simulation result has high precision.

Description

Technical Field

[0001] This invention relates to a vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling, belonging to the field of vehicle dynamics simulation technology. Background Technology

[0002] When performing vehicle dynamics simulation analysis, some components exhibit significant elastic deformation and large vibrations. Treating these components as rigid bodies would inevitably reduce the accuracy of the simulation. Therefore, it is necessary to treat components with large elastic deformation as flexible bodies and establish a multi-body dynamics model of the vehicle that combines rigid and flexible bodies. However, in establishing flexible body models of components, most current modeling methods use modal neutral files in a free state, which differs from the actual state and reduces the accuracy of vehicle dynamics simulation. Furthermore, most current vehicle dynamics modeling methods include road surface and tire models. Road surface models often use two-dimensional randomly generated roads or three-dimensional virtual reconstructions, resulting in significant errors compared to the real road surface contours, inevitably reducing the accuracy of vehicle dynamics simulation. Tire models often use models provided by ADAMS software, and the parameters of these built-in tire models deviate significantly from the actual vehicle tire parameters, causing distortion in the vehicle dynamics simulation results. Additionally, when dealing with the contact problem between the tire and the ground, the equivalent road shape method is often used, but the equivalent road shape used differs from the actual input road surface, also contributing to simulation errors. To improve the accuracy of vehicle dynamics simulation and reduce the error between simulation and experiment, a rigid-flexible coupling dynamics modeling method for vehicles based on shaft coupling is proposed. Summary of the Invention

[0003] The purpose of this invention is to propose a vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling. This method can improve the modeling accuracy of flexible bodies, solve the problem of the influence of uncertainties in road surface models and tire models on vehicle dynamics simulation results, and at the same time improve the accuracy of vehicle dynamics simulation and reduce the error between simulation and experiment.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling, comprising the following steps:

[0005] Step 1: Establish a multi-rigid-body dynamics model of the vehicle that does not include the road surface model and the tire model;

[0006] Step 2: Establish a rigid-flexible coupled dynamic model of the vehicle;

[0007] Step 3: Establish a virtual test bench with three-dimensional displacement input function;

[0008] Step 4: Collect relative displacement data between the axle head and the vehicle frame under actual road conditions;

[0009] Step 5: Perform vehicle dynamics simulation and model calibration.

[0010] Furthermore, step 1 includes the following steps:

[0011] Step 1.1: Extract the suspension stiffness coordinates, engine mount hard point coordinates, body center of gravity coordinates, steering system stiffness coordinates, and transmission system hard point coordinates from the vehicle 3D model, and establish the spatial position coordinates of the vehicle suspension, engine mount, body, steering system, and transmission system in ADAMS / VIEW.

[0012] Step 1.2: Calculate the mass and moment of inertia of the vehicle engine, body and transmission system; calculate the stiffness of the elastic element and the damping coefficient of the damping element.

[0013] Step 1.3: Based on the hard point coordinates in the previous steps, establish the structural models of each system of the vehicle, add the mass attributes of the components, set the constraint relationships between the parts according to the connection relationships between the systems, and establish the dynamic models of each system of the vehicle.

[0014] Step 1.4: Integrate the vehicle system dynamics models obtained in the previous steps onto the same ADAMS / VIEW platform, set the constraint relationships between the systems, and establish a vehicle multi-rigid-body dynamics model. The vehicle multi-rigid-body dynamics model does not include the road surface model and the tire model.

[0015] Step 1.5: Perform degree of freedom and static balance simulations on the established vehicle multi-rigid-body dynamics model to verify the accuracy of the model.

[0016] Furthermore, step 2 includes the following steps:

[0017] Step 2.1: Use finite element software to perform geometric cleanup, mid-surface extraction, mesh generation, and mesh quality optimization on the elastic component model, and add material properties and constraint relationships;

[0018] Step 2.2: Perform constrained modal simulation calculations on the finite element models of the components from the previous steps, and extract the modal neutral files;

[0019] Step 2.3: Import the modal neutral files of the components from the previous steps into ADAMS / VIEW to build a flexible body model, and verify the natural frequencies, mode shapes and mass information of the flexible body model;

[0020] Step 2.4: Replace the corresponding rigid body model with the flexible body model established in the previous steps, and reset the constraint relationships to establish a rigid-flexible coupling dynamic model of the vehicle.

[0021] Step 2.5: Perform modal simulation and static balance simulation on the established rigid-flexible coupled dynamic model of the vehicle to verify the accuracy of the model.

[0022] Furthermore, in step 2, the elastic component should be treated as a flexible body, and the rigid component should be treated as a rigid body.

[0023] Furthermore, step 3 includes the following steps:

[0024] Step 3.1: Establish a floating platform at each axle head location, i.e., at the wheel center;

[0025] Step 3.2: Set a slider at the same distance from each floating platform along the X, Y, and Z directions, and set a spring between each slider and the floating platform. The stiffness of the spring is 100 times the vertical stiffness of the tire.

[0026] Step 3.3: Establish a sliding joint between each slider and the ground, with the direction of the sliding joint pointing towards the slider;

[0027] Step 3.4: Set a driving slider on each sliding joint;

[0028] Step 3.5: Install a bidirectional spring between the floating platform and each drive slider;

[0029] Step 3.6: Using model integration technology, the rigid-flexible coupling dynamics model of the vehicle is integrated into the virtual test bench, the constraint relationship between the axle head and the floating platform is set, and a rigid-flexible coupling dynamics model of the vehicle based on axle coupling is established.

[0030] Furthermore, in step 3, the three-dimensional displacement input refers to simultaneously adding X-axis, Y-axis, and Z-axis displacement excitations to each floating platform to drive the vehicle's movement.

[0031] Furthermore, step 4 includes the following steps:

[0032] Step 4.1: Arrange a wire-drawing sensor in each of the X, Y, and Z directions between each axle head and the frame, and use an LMS to collect the relative displacement between the axle head and the frame;

[0033] Step 4.2: Use data post-processing software to filter, deburr, and de-drift the acquired relative displacement data;

[0034] Step 4.3: Convert the relative displacement test data in the X, Y, and Z directions processed in the previous steps into a TXT file;

[0035] Step 4.4: Import the test data TXT file of relative displacement in the X, Y, and Z directions into ADAMS to create SPLINE curves of relative displacement in the X, Y, and Z directions.

[0036] Furthermore, step 5 includes the following steps:

[0037] Step 5.1: Using AKISPL, call the function to obtain the relative displacement SPLINE curves in the X, Y, and Z directions established in Step 4 to perform dynamic simulation;

[0038] Step 5.2: Collect time-domain acceleration data on the vehicle frame in the vehicle dynamics model;

[0039] Step 5.3 Under actual road conditions, collect time-domain acceleration data from the vehicle frame using a three-dimensional accelerometer and an LMS device;

[0040] Step 5.4 involves comparing the simulation results of the chassis acceleration with the experimental data to ultimately prove the simulation accuracy of the modeling method.

[0041] The beneficial effects of this invention are as follows:

[0042] This invention provides a vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling. It comprehensively utilizes the principles of rigid-flexible coupling dynamics, finite element theory, and virtual iteration technology to establish a vehicle rigid-flexible coupling dynamics model based on shaft coupling. This improves the modeling accuracy of flexible bodies, avoids the influence of errors between road surface models and tire models on simulation accuracy in traditional modeling methods, and enhances the accuracy of vehicle dynamics simulation. It has high reliability, applicability, and operability. Attached Figure Description

[0043] Figure 1 This is a flowchart of the present invention.

[0044] Figure 2 This is a schematic diagram of the vehicle rigid-flexible coupling dynamics model based on shaft coupling according to the present invention.

[0045] Figure 3 for Figure 2 A partial schematic diagram.

[0046] Among them, 1-virtual test bench; 2-vehicle dynamics model; 3-floating platform; 4-slider; 5-spring. Detailed Implementation

[0047] The present invention will now be further described with reference to the accompanying drawings.

[0048] This embodiment presents a vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling. Through analysis of the current status of existing vehicle dynamics modeling methods, it is found that the flexible body modeling method, road surface model, and tire model currently used will significantly reduce the accuracy of vehicle dynamics simulation. This invention provides a vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling to solve the above problems and effectively improve the accuracy of vehicle dynamics simulation.

[0049] The implementation of this solution mainly includes the following steps:

[0050] Establish a multi-rigid-body dynamics model for the vehicle that does not include road surface and tire models.

[0051] The steps to establish a multi-rigid-body dynamics model of a vehicle are as follows:

[0052] Extract the coordinates of each hard point from the vehicle's 3D model and establish the spatial position coordinates of each vehicle system in ADAMS / VIEW;

[0053] Calculate the mass and moment of inertia of each system of the vehicle, and calculate the stiffness of the elastic elements and the damping coefficient of the damping elements.

[0054] Based on the hard point coordinates, establish dynamic models of the front axle, rear axle, front suspension, rear suspension, power mount system, frame, and body, respectively, and add mass attributes of the components and set constraints;

[0055] By merging subsystem models, a multi-rigid-body dynamics model of the vehicle is established, which does not include road surface and tire models.

[0056] The established multi-rigid-body dynamics model of the vehicle was checked for degrees of freedom and static balance to verify the accuracy of the model.

[0057] Establishing a rigid-flexible coupled dynamic model of the vehicle includes the following steps:

[0058] Finite element method software was used to perform geometric cleanup, mid-surface extraction, mesh generation, and mesh quality optimization on the 3D model of the vehicle frame, and material properties and constraints were added.

[0059] Constrained modal simulation calculations were performed on the finite element model of the chassis, and modal neutral files were extracted.

[0060] Import the frame constraint modal neutral file into ADAMS / VIEW and verify the natural frequencies, mode shapes, and mass information of the frame flexible body model;

[0061] The rigid body model of the vehicle frame is replaced by a flexible body model of the vehicle frame, and the constraint relationships are reset to establish a rigid-flexible coupled dynamic model of the vehicle.

[0062] Modal simulation and static balance simulation were performed on the established rigid-flexible coupled dynamic model of the vehicle to verify the accuracy of the model; the results of the frame modal calibration are shown in Table 1, and the results of the vehicle mass and center of mass coordinate calibration are shown in Table 2.

[0063] Table 1. Chassis Modal Calibration Results

[0064]

[0065]

[0066] Table 2 Calibration Results of Vehicle Mass and Centroid Coordinates

[0067]

[0068] To establish a virtual test bench with three-dimensional displacement input capabilities, see [link to relevant documentation]. Figure 2 It includes the following steps:

[0069] Build one floating platform at each axle head position (at the wheel center);

[0070] Build a slider 200mm away from each floating platform along the X, Y, and Z directions;

[0071] A sliding joint is established between the slider and the ground, with the sliding joint pointing towards the slider;

[0072] Build one drive slider on each moving pair;

[0073] One spring is installed between the floating platform and each drive slider. The vertical stiffness of the tire is 650 N / mm, and the spring stiffness is approximately 65000 N / mm.

[0074] Using model integration technology, the rigid-flexible coupled dynamics model of the vehicle is integrated into a virtual test bench. The constraint relationship between the axle head and the floating platform is set, and a rigid-flexible coupled dynamics model of the vehicle based on axle coupling is established.

[0075] Collecting relative displacement data between the axle head and the vehicle frame under actual road conditions includes the following steps:

[0076] A wire-drawing sensor is arranged in each of the X, Y, and Z directions between each axle head and the frame, and the LMS is used to collect the relative displacement between the axle head and the frame.

[0077] Data post-processing software was used to filter, deburr, and de-drift the acquired relative displacement data.

[0078] The processed relative displacement test data in the X, Y, and Z directions are converted into TXT files;

[0079] Import the relative displacement test data TXT file in the X, Y, and Z directions into ADAMS to establish X, Y, and Z coordinates.

[0080] SPLINE curves showing the relative displacement in the three Z directions.

[0081] Vehicle dynamics simulation and model calibration include the following steps:

[0082] The relative displacement SPLINE curves in the X, Y, and Z directions established in step (4) are called using the AKISPL(time, 0, SPLINE name, 0) function to perform dynamic simulation;

[0083] Collect time-domain acceleration data on the vehicle frame in the vehicle dynamics model;

[0084] In actual road conditions, the three-dimensional acceleration sensor and LMS equipment are used to collect time-domain acceleration data on the vehicle frame;

[0085] The simulation results of the chassis acceleration were compared with the experimental data. The comparison results of the root mean square value of the acceleration at the left front end of the chassis at different vehicle speeds are shown in Table 3, the comparison results of the root mean square value of the acceleration at the left rear end of the chassis are shown in Table 4, the comparison results of the vibration isolation rate of the front suspension are shown in Table 5, and the comparison results of the vibration isolation rate of the rear suspension are shown in Table 6.

[0086] Table 3. Benchmarking results of root mean square acceleration values ​​at the left front end of the chassis.

[0087] Vehicle speed (km / h) 30 50 70 90 110 <![CDATA[Simulation results (m / s 2 )]]> 0.33 0.37 0.45 0.48 0.54 <![CDATA[Test results (m / s 2 )]]> 0.31 0.4 0.44 0.52 0.58 fit 93.9％ 92.5％ 97.8％ 92.3％ 93.1％

[0088] Table 4. Benchmarking results of root mean square acceleration values ​​at the left rear end of the chassis.

[0089] Vehicle speed (km / h) 30 50 70 90 110 <![CDATA[Simulation results (m / s 2 )]]> 0.39 0.48 0.54 0.61 0.77 <![CDATA[Test results (m / s 2 )]]> 0.42 0.46 0.58 0.66 0.83 fit 92.9％ 95.8％ 93.1％ 92.4％ 92.8％

[0090] Table 5. Benchmarking Results of Front Suspension Vibration Isolation Rate

[0091] Vehicle speed (km / h) 30 50 70 90 110 Simulation results 63.0％ 67.0％ 64.0％ 62.0％ 59.0％ Test results 59.0％ 62.0％ 59.0％ 63.0％ 61.0％ fit 93.7％ 92.5％ 92.2％ 98.4％ 96.7％

[0092] Table 6. Benchmark Results of Rear Suspension Vibration Isolation Rate

[0093] Vehicle speed (km / h) 30 50 70 90 110 Simulation results 55.0％ 59.0％ 56.0％ 52.0％ 51.0％ Test results 51.0％ 55.0％ 59.0％ 56.0％ 56.0％ fit 92.7％ 93.2％ 94.9％ 92.9％ 91.1％

[0094] The agreement between the simulation data and the experimental data in Tables 3 to 6 is greater than 90%, which proves that the vehicle rigid-flexible coupling dynamic modeling method based on shaft coupling of the present invention can improve the accuracy of vehicle dynamics simulation and has high reliability, applicability and operability.

[0095] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling, characterized in that, Includes the following steps: Step 1: Establish a multi-rigid-body dynamics model of the vehicle that does not include the road surface model and the tire model; Step 2: Establish a rigid-flexible coupled dynamic model of the vehicle; Step 3: Establish a virtual test bench with three-dimensional displacement input capability. Three-dimensional displacement input refers to simultaneously adding X-axis, Y-axis, and Z-axis displacement excitations to each floating platform to drive vehicle movement, as detailed below: Step 3.1: Establish a floating platform at each axle head location, i.e., at the wheel center; Step 3.2: Set a slider at the same distance from each floating platform along the X, Y, and Z directions, and set a spring between each slider and the floating platform. The stiffness of the spring is 100 times the vertical stiffness of the tire. Step 3.3: Establish a sliding joint between each slider and the ground, with the direction of the sliding joint pointing towards the slider; Step 3.4: Set a driving slider on each sliding joint; Step 3.5: Install a bidirectional spring between the floating platform and each drive slider; Step 3.6: Using model integration technology, the rigid-flexible coupling dynamics model of the vehicle is integrated into the virtual test bench, the constraint relationship between the axle head and the floating platform is set, and a rigid-flexible coupling dynamics model of the vehicle based on axle coupling is established. Step 4: Collect relative displacement data between the axle head and the vehicle frame under actual road conditions; Step 5: Perform vehicle dynamics simulation and model calibration.

2. The vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling according to claim 1, characterized in that: Step 1 includes the following steps: Step 1.1: Extract the suspension stiffness coordinates, engine mount hard point coordinates, body center of gravity coordinates, steering system stiffness coordinates, and transmission system hard point coordinates from the vehicle 3D model, and establish the spatial position coordinates of the vehicle suspension, engine mount, body, steering system, and transmission system in ADAMS / VIEW. Step 1.2: Calculate the mass and moment of inertia of the vehicle engine, body and transmission system; calculate the stiffness of the elastic element and the damping coefficient of the damping element. Step 1.3: Based on the hard point coordinates in the previous steps, establish the structural models of each system of the vehicle, add the mass attributes of the components, set the constraint relationships between the parts according to the connection relationships between the systems, and establish the dynamic models of each system of the vehicle. Step 1.4: Integrate the vehicle system dynamics models obtained in the previous steps onto the same ADAMS / VIEW platform, set the constraint relationships between the systems, and establish a vehicle multi-rigid-body dynamics model. The vehicle multi-rigid-body dynamics model does not include the road surface model and the tire model. Step 1.5: Perform degree of freedom and static balance simulations on the established vehicle multi-rigid-body dynamics model to verify the accuracy of the model.

3. The vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling according to claim 1, characterized in that: Step 2 includes the following steps: Step 2.1: Use finite element software to perform geometric cleanup, mid-surface extraction, mesh generation, and mesh quality optimization on the elastic component model, and add material properties and constraint relationships; Step 2.2: Perform constrained modal simulation calculations on the finite element models of the components from the previous steps, and extract the modal neutral files; Step 2.3: Import the modal neutral files of the components from the previous steps into ADAMS / VIEW to build a flexible body model, and verify the natural frequencies, mode shapes and mass information of the flexible body model; Step 2.4: Replace the corresponding rigid body model with the flexible body model established in the previous steps, and reset the constraint relationships to establish a rigid-flexible coupling dynamic model of the vehicle. Step 2.5: Perform modal simulation and static balance simulation on the established rigid-flexible coupled dynamic model of the vehicle to verify the accuracy of the model.

4. The vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling according to claim 3, characterized in that: In step 2, the elastic component should be treated as a flexible body, and the rigid component should be treated as a rigid body.

5. The vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling according to claim 1, characterized in that: Step 4 includes the following steps: Step 4.1: Arrange a wire-drawing sensor in each of the X, Y, and Z directions between each axle head and the frame, and use an LMS to collect the relative displacement between the axle head and the frame; Step 4.2: Use data post-processing software to filter, deburr, and de-drift the acquired relative displacement data; Step 4.3: Convert the relative displacement test data in the X, Y, and Z directions processed in the previous steps into a TXT file; Step 4.4: Import the test data TXT file of relative displacement in the X, Y, and Z directions into ADAMS to create SPLINE curves of relative displacement in the X, Y, and Z directions.

6. The vehicle rigid-flexible coupling dynamics modeling method based on shaft coupling according to claim 1, characterized in that: Step 5 includes the following steps: Step 5.1: Using AKISPL, call the function to obtain the relative displacement SPLINE curves in the X, Y, and Z directions established in Step 4 to perform dynamic simulation; Step 5.2: Collect time-domain acceleration data on the vehicle frame in the vehicle dynamics model; Step 5.3, under actual road conditions, collect time-domain acceleration data from the vehicle frame using a three-dimensional accelerometer and an LMS device; Step 5.4 involves comparing the simulation results of the chassis acceleration with the experimental data to ultimately prove the simulation accuracy of the modeling method.

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