A steering wheel vibration simulation method and system

Abstract

The application discloses a steering wheel vibration simulation method, which comprises the following steps: step S10, establishing finite element models of a steering system, a chassis system and a vehicle body system based on a whole vehicle structure; step S11, assembling the finite element models of the steering system, the chassis system and the vehicle body system into a finite element model of the whole vehicle according to the mutual connection relationship among the systems in the whole vehicle; step S12, extracting road excitation loads under different working conditions; and step S13, inputting the road excitation loads into the finite element model of the whole vehicle, performing simulation calculation processing, and obtaining steering wheel vibration response information. The application further discloses a corresponding system. According to the application, the load input is closer to the characteristics of real vehicle driving working conditions, the steering wheel vibration simulation is more optimized, and the obtained data is more accurate.

Description

Technical Field

[0001] This invention relates to the technical field of automotive noise, vibration, and acoustic roughness (NVH), and in particular to a method and system for simulating steering wheel vibration. Background Technology

[0002] As people's living standards improve, passengers are increasingly demanding higher levels of comfort, stability, and NVH performance from vehicles. Steering wheel vibration is directly felt by the driver while the car is in motion and directly affects passengers' subjective evaluation of these aspects of the vehicle's performance.

[0003] Therefore, the performance of steering wheel vibration is often evaluated during the development and use of vehicles.

[0004] In the existing technology, when evaluating the vibration performance of the steering wheel, the main approach is to use the modal control of the steering wheel-steering column-CCB. This method can effectively avoid the resonance problem of the steering wheel under engine idling conditions, but it cannot reflect the impact of road excitation on steering wheel vibration under driving conditions.

[0005] In other existing technical solutions, vibration loads can be simulated by artificially applying dynamic imbalance to the tires in the simulation model, thereby obtaining the steering wheel's shimmy response. However, this approach does not consider the road surface characteristics under actual operating conditions, resulting in a significant discrepancy with the actual driving road surface. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that it proposes a steering wheel vibration simulation method and system, the load input of which is closer to the characteristics of actual vehicle driving conditions, thereby optimizing the steering wheel vibration simulation and obtaining more accurate data.

[0007] To solve the above-mentioned technical problems, a steering wheel vibration simulation method, as one aspect of the present invention, includes the following steps:

[0008] Step S10: Based on the overall vehicle structure, establish finite element models of the steering system, chassis system, and body system;

[0009] Step S11: According to the interconnection relationship between the various systems in the vehicle, assemble the finite element models of the steering system, chassis system, and body system into the finite element model of the whole vehicle.

[0010] Step S12: Extract the road surface excitation load under different working conditions;

[0011] Step S13: Input the road excitation load into the finite element model of the whole vehicle for simulation calculation and obtain steering wheel vibration response information.

[0012] Step S10 includes the step of establishing a finite element model of the steering system, specifically including:

[0013] Mesh models of the steering tie rod, steering gear, steering column, and steering wheel components in the steering system are generated using the finite element modeling method.

[0014] The steering tie rod, steering gear, steering column, and steering wheel are connected using simulation units. The ball joint between the steering tie rod and the steering gear is simulated using RBE2 units; the gear-rack meshing in the steering gear is simulated using MPC units; and the bending stiffness of the steering column is simulated using Cbush units.

[0015] Establish a local coordinate system, taking the direction from the six o'clock position to the twelve o'clock position of the steering wheel as the X-axis of the local coordinate system, the Y-axis of the entire vehicle as the Y-axis of the local coordinate system, and the direction of the steering column axis as the Z-axis of the local coordinate system.

[0016] Step S10 includes the step of establishing a finite element model of the chassis system, specifically including:

[0017] Mesh models of the subframe, suspension, axle joints, tires, and stabilizer bars in the chassis system are generated using the finite element modeling method.

[0018] The vibration damper is modeled by establishing a mesh model of the outer cylinder and top rod of the vibration damper, and Cbush elements are used to simulate the connection between the two. The parameters in the X and Y directions represent the bending characteristics of the vibration damper, and the parameters in the Z direction represent the displacement-force characteristics of the vibration damper under tension and compression. For the top of the vibration damper, Cbush elements are used to represent its stiffness and damping characteristics.

[0019] Step S10 includes the step of establishing a finite element model of the vehicle body system, specifically including:

[0020] The steering column support was modeled in detail using the finite element method.

[0021] For the rest of the vehicle body, a simplified Plotel element was used for simulation.

[0022] Step S11 further includes:

[0023] The steering system, chassis system, and body system are assembled into a complete vehicle model according to the interconnection relationships of the various systems in the actual vehicle. The bolt connections are simulated in the model using RBE2 elements, and the bushing connections are simulated using Cbush. The interconnection relationships further include the gear-rack constraint relationship of the steering system, the suspension-tire constraint relationship of the chassis system, and the constraint relationship between the body and CCB system on the steering system.

[0024] In step S12, the road surface excitation load is extracted using any of the following methods:

[0025] The road excitation load is obtained from the road load file in the finite element software.

[0026] Based on the road surface feature data obtained from the road spectrum scan, the time-domain curve is transformed by FFT to obtain the frequency-domain curve, and the load of each wheel is obtained.

[0027] The forces and moments in six directions at each wheel center are obtained by inverse matrix method, thus obtaining the wheel center load of each wheel.

[0028] The step of obtaining the wheel center load by inversely calculating the forces and moments in six directions of each wheel center using the inverse matrix method further includes:

[0029] For different working conditions, m triaxial acceleration sensors are arranged around the shaft joint, and the acceleration signals of these m sensors are measured.

[0030] In the finite element model of the chassis system, the wheels are removed, and the m triaxial accelerations arranged around the axle joint remain unchanged. n points are selected on the brake disc, and the transfer functions from the n points to the m accelerations are measured using the hammer impact method to form the transfer function matrix [H]. The coordinates of each impact point relative to the wheel center are recorded.

[0031] The wheel center load is obtained using the following inverse matrix formula:

[0032] F = [H] -1 A;

[0033] Where [H] is the measured transfer matrix, [H] -1 For its generalized inverse, [H] -1 It is a 3n×3m matrix, where n and m are the number of tapping points and sensors, respectively, and F is a 3n×1 row vector;

[0034] Based on the geometric matrix and the principle of geometric reduction, the forces and moments in the six directions of the shaft head can be obtained using the following formulas.

[0035]

[0036]

[0037] Where F is the aforementioned 3n×1 row vector, [C] is the geometric reduction matrix, and x, y, z are the coordinates of the aforementioned striking point relative to the wheel center; The row vectors are 6×1, representing the three translational forces and three rotational torques of the wheel center.

[0038] Step S13 further includes:

[0039] Based on the four-wheel load signals collected from the road spectrum, the cross spectrum of the four-wheel load is calculated, and the load is imported into the whole vehicle model for calculation to obtain steering wheel vibration response information;

[0040] After independently determining the forces and moments in six directions at the four wheel centers, the vibration response of the steering wheel can be calculated using the formula:

[0041]

[0042] Wherein, FRF is the transfer function from the four wheel centers to the steering wheel.

[0043] Accordingly, the present invention also provides a steering wheel vibration simulation system, which includes:

[0044] The subsystem model building unit is used to build finite element models of the steering system, chassis system, and body system based on the overall vehicle structure.

[0045] The vehicle model building unit is used to assemble the finite element models of the steering system, chassis system, and body system into a finite element model of the whole vehicle according to the interconnection relationship between the various systems in the whole vehicle.

[0046] The road surface excitation load extraction unit is used to extract road surface excitation loads under different working conditions;

[0047] The steering wheel vibration response acquisition unit is used to input the road excitation load into the finite element model of the whole vehicle, perform simulation calculations, and obtain steering wheel vibration response information.

[0048] The subsystem model building unit includes a steering system model building unit, which comprises:

[0049] The steering component mesh model building unit is used to generate mesh models of various components in the steering system, such as the steering tie rod, steering gear, steering column, and steering wheel, based on the finite element modeling method.

[0050] The connection processing unit is used to connect the steering tie rod, steering gear, steering column, and steering wheel using simulation units. The ball joint between the steering tie rod and the steering gear is simulated using RBE2 units; the gear-rack meshing in the steering gear is simulated using MPC units; and the bending stiffness of the steering column is simulated using Cbush units.

[0051] The local coordinate system establishment unit is used to establish a local coordinate system. The direction from the six o'clock position to the twelve o'clock position of the steering wheel is taken as the X-direction of the local coordinate system, the Y-direction of the whole vehicle is taken as the Y-direction of the local coordinate system, and the direction of the steering column axis is taken as the Z-direction of the local coordinate system.

[0052] The subsystem model building unit includes a chassis system model building unit and a body system model building unit. The chassis system model building unit includes:

[0053] The chassis component mesh modeling unit is used to generate mesh models of various components in the chassis system, such as the subframe, suspension, axle joints, tires, and stabilizer bars, based on the finite element modeling method.

[0054] The vibration damper modeling unit is used to model the vibration damper, establish the mesh model of the outer cylinder and top rod of the vibration damper, and use Cbush elements to simulate the connection between the two; the parameters in the X and Y directions characterize the bending characteristics of the vibration damper, and the parameters in the Z direction characterize the displacement-force characteristics of the vibration damper under tension and compression; for the TopMount at the top of the vibration damper, Cbush elements are used to characterize its stiffness and damping characteristics.

[0055] The vehicle body system model building unit includes:

[0056] The steering column support modeling unit is used to perform detailed modeling of the steering column support according to the finite element modeling method.

[0057] The remaining body parts are modeled using Plotel simplified elements for simulation.

[0058] In the vehicle model building unit, bolt connections are simulated using RBE2 units, and bushing connections are simulated using Cbush units. The interconnections further include the gear-rack constraint relationship of the steering system, the suspension-tire constraint relationship of the chassis system, and the constraint relationship between the body and the CCB system on the steering system.

[0059] The road surface excitation load extraction unit includes:

[0060] The first extraction unit is used to obtain the pavement excitation load based on the pavement load file in the finite element software.

[0061] The second extraction unit is used to perform FFT transformation on the time-domain curve to obtain the frequency-domain curve based on the road surface feature data obtained by road spectrum scanning, and to obtain the load of each wheel.

[0062] The third extraction unit is used to obtain the forces and moments in six directions of each wheel center by inverse matrix method, thereby obtaining the wheel center load of each wheel.

[0063] The third extraction unit further includes:

[0064] The sensing signal acquisition unit is used to arrange m triaxial acceleration sensors around the shaft joint for different working conditions and measure the acceleration signals of the m sensors.

[0065] The hammer impact measurement unit is used to disassemble the wheel in the finite element model of the chassis system, keeping the m triaxial accelerations arranged around the axle joint unchanged, selecting n points on the brake disc, and using the hammer impact method to measure the transfer function from the n points to the m accelerations to form the transfer function matrix [H], and recording the coordinates of each impact point relative to the wheel center;

[0066] The wheel center load calculation unit is used to obtain the wheel center load using the following inverse matrix formula:

[0067] F = [H] -1 A;

[0068] Where [H] is the measured transfer matrix, [H] -1 For its generalized inverse, [H] -1 It is a 3n×3m matrix, where n and m are the number of tapping points and sensors, respectively, and F is a 3n×1 row vector;

[0069] The wheel center torque acquisition unit is used to obtain the forces and torques in six directions at the axle head based on the geometric matrix and the principle of geometric reduction, using the following formula.

[0070]

[0071]

[0072] Where F is the aforementioned 3n×1 row vector, [C] is the geometric reduction matrix, and x, y, z are the coordinates of the aforementioned striking point relative to the wheel center; The row vectors are 6×1, representing the three translational forces and three rotational torques of the wheel center.

[0073] The steering wheel vibration response acquisition unit further includes:

[0074] The first processing unit is used to calculate the cross spectrum of the four-wheel loads based on the four-wheel load signals collected from the road spectrum, and import the loads into the whole vehicle model for calculation to obtain steering wheel vibration response information.

[0075] The second processing unit, after independently calculating the forces and moments in six directions at the four wheel centers, calculates the vibration response of the steering wheel according to the formula:

[0076]

[0077] Wherein, FRF is the transfer function from the four wheel centers to the steering wheel.

[0078] Implementing the embodiments of the present invention has the following beneficial effects:

[0079] This invention provides a simulation method and system for steering wheel vibration, which involves establishing a whole vehicle simulation model and importing road surface excitation loads under different working conditions. The whole vehicle simulation model considers the gear-rack constraint relationship of the steering system, the suspension-tire constraint relationship of the chassis system, and the constraint relationship between the body and CCB system on the steering system. In extracting road surface excitation loads, three methods for extracting road surface loads are proposed, fully considering the modeling of the steering system under the whole vehicle, making it more comprehensive and accurate than previous steering system modeling methods.

[0080] In embodiments of the present invention, steering wheel vibration can be predicted in the early stages of vehicle development, and the vibration of the steering wheel under different road surfaces can be predicted. Based on this, the optimization of steering wheel vibration can be carried out in the early stages of project research and development, and the development cycle can be shortened.

[0081] In this embodiment of the invention, road surface excitation load extraction under different working conditions is considered, making the load input of the invention closer to the characteristics of actual vehicle driving conditions. Attached Figure Description

[0082] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0083] Figure 1 This is a schematic diagram of the main flow of an embodiment of a steering wheel vibration simulation method provided by the present invention;

[0084] Figure 2 A schematic diagram of a structure of an embodiment of a steering wheel vibration simulation system provided by the present invention;

[0085] Figure 3 for Figure 2 A schematic diagram of the structure of the unit used to build the model of the central distribution system;

[0086] Figure 4 for Figure 3 A schematic diagram of the structural unit for establishing the steering system model;

[0087] Figure 5 yes Figure 3 A schematic diagram of the structure of the model building unit for the mid-chassis system;

[0088] Figure 6 yes Figure 4 A schematic diagram of the structure of the body system model building unit;

[0089] Figure 7 yes Figure 2 Schematic diagram of the structure of the road surface excitation load extraction unit;

[0090] Figure 8 yes Figure 7 A schematic diagram of the structure of the third extraction unit;

[0091] Figure 9 yes Figure 2 A schematic diagram of the structure of the steering wheel vibration response acquisition unit. Detailed Implementation

[0092] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0093] like Figure 1 The diagram shows the main flow chart of an embodiment of a steering wheel vibration simulation method provided by the present invention; in this embodiment, the steering wheel vibration simulation method includes the following steps:

[0094] Step S10: Based on the overall vehicle structure, establish finite element models of the steering system, chassis system, and body system;

[0095] Specifically, in one example, step S10 includes the step of establishing a finite element model of the steering system, specifically including:

[0096] Mesh models of the steering tie rod, steering gear, steering column, and steering wheel components in the steering system are generated using the finite element modeling method.

[0097] The steering tie rod, steering gear, steering column, and steering wheel are connected using simulation units. The ball joint between the steering tie rod and the steering gear is simulated using RBE2 units (rigid units), which can restrict its translational degrees of freedom while releasing its rotational degrees of freedom. The gear-rack meshing in the steering gear is simulated using MPC units, where the parameters of the MPC are set according to the actual meshing ratio. The bending stiffness of the steering column is simulated using Cbush units, and its Pbush property is corrected according to the results of bench test.

[0098] A local coordinate system is established. Considering that the steering wheel sensor is usually located at the 12 o'clock position of the steering wheel during actual vehicle testing, the direction from the 6 o'clock position to the 12 o'clock position of the steering wheel is taken as the X-direction of the local coordinate system, the Y-direction of the whole vehicle is taken as the Y-direction of the local coordinate system, and the direction of the steering column axis is taken as the Z-direction of the local coordinate system.

[0099] In the embodiments of the present invention, Hypermesh and Nastran are used as pre- and post-processing software for modeling and calculation; Cbush and Pbush elements are commonly used connection elements in Nastran, which are general-purpose triaxial spring-damper elements that can define stiffness and damping in up to six directions (three translational and three rotational); MPC elements are multi-point coupled elements.

[0100] Specifically, in one example, step S10 includes the step of establishing a finite element model of the chassis system, specifically including:

[0101] Mesh models of the subframe, suspension, axle joints, tires, and stabilizer bars in the chassis system are generated using the finite element modeling method. Among them, the tires are commercial tire models, and the tire size, tire pressure, and lateral and radial stiffness are adjusted according to the actual vehicle.

[0102] The vibration damper is modeled by establishing a mesh model of the outer cylinder and top rod, and Cbush elements are used to simulate the connection between them. The Pbush attribute is set according to the results of the vibration damper bench test. The parameters in the X and Y directions characterize the bending characteristics of the vibration damper, and the parameters in the Z direction characterize the displacement-force characteristics of the vibration damper under tension and compression. For the TopMount at the top of the vibration damper, Cbush elements are used to characterize its stiffness and damping characteristics.

[0103] Specifically, in one example, step S10 includes the step of establishing a finite element model of the vehicle body system, specifically including:

[0104] The steering column bracket (CCB) is modeled in detail using the finite element method, and its dynamic stiffness at the mounting point affects the mode of the steering system.

[0105] For the rest of the vehicle body, Plotel simplified cells were used for simulation to improve computational efficiency.

[0106] Step S11: According to the interconnection relationship between the various systems in the vehicle, assemble the finite element models of the steering system, chassis system, and body system into the finite element model of the whole vehicle.

[0107] Specifically, in one example, step S11 further includes:

[0108] The steering system, chassis system, and body system are assembled into a complete vehicle model according to the interconnection relationships of the various systems in the actual vehicle. The bolt connections are simulated in the model using RBE2 elements, and the bushing connections are simulated using Cbush elements. During this process, the parameters of the Cbush elements are set according to the actual stiffness and damping of the bushings. The interconnection relationships further include the gear-rack constraint relationship of the steering system, the suspension-tire constraint relationship of the chassis system, and the constraint relationship between the body and the CCB system on the steering system.

[0109] Step S12: Extract the road surface excitation load under different working conditions;

[0110] Specifically, in the embodiments of the present invention, step S12 employs any of the following methods to extract the road surface excitation load:

[0111] The road excitation load is obtained from the road load file in the finite element software.

[0112] Based on the road surface feature data obtained from the road spectrum scan, the time-domain curve is transformed by FFT to obtain the frequency-domain curve, and the load of each wheel is obtained.

[0113] The forces and moments in six directions at each wheel center are obtained by inverse matrix method, thus obtaining the wheel center load of each wheel.

[0114] For the third method, the step of obtaining the wheel center load by inversely calculating the forces and moments in six directions of each wheel center using the inverse matrix method further includes:

[0115] For different working conditions, m triaxial acceleration sensors are arranged around the shaft joint, and the acceleration signals of these m sensors are measured.

[0116] In the finite element model of the chassis system, the wheels are removed, and the m triaxial accelerations arranged around the axle joint remain unchanged. n points are selected on the brake disc, and the transfer functions from the n points to the m accelerations are measured using the hammer impact method to form the transfer function matrix [H]. The coordinates of each impact point relative to the wheel center are recorded.

[0117] The wheel center load is obtained using the following inverse matrix formula:

[0118] F = [H] -1 A;

[0119] Where [H] is the measured transfer matrix, [H] -1 For its generalized inverse, this invention uses triaxial acceleration, so [H] can be seen. -1 It is a 3n×3m matrix, where n and m are the number of tapping points and sensors, respectively, and F is a 3n×1 row vector;

[0120] Based on the geometric matrix and the principle of geometric reduction, the forces and moments in the six directions of the shaft head can be obtained using the following formulas.

[0121]

[0122]

[0123] Where F is the aforementioned 3n×1 row vector, [C] is the geometric reduction matrix, and x, y, z are the coordinates of the aforementioned striking point relative to the wheel center; The row vectors are 6×1, representing the three translational forces and three rotational torques of the wheel center.

[0124] Step S13: Input the road excitation load into the finite element model of the whole vehicle for simulation calculation and obtain steering wheel vibration response information.

[0125] Specifically, for the first method in step S12, refer to the user manual of the software used.

[0126] For the second method in step S12, step S13 further includes:

[0127] Based on the four-wheel load signals collected from the road spectrum, the cross spectrum of the four-wheel load is calculated, and the load is imported into the whole vehicle model for calculation to obtain steering wheel vibration response information.

[0128] For the third method in step S12, step S13 further includes:

[0129] After independently determining the forces and moments in six directions at the four wheel centers, the vibration response of the steering wheel can be calculated using the formula:

[0130]

[0131] Among them, FRF is the transfer function from the four wheel centers to the steering wheel, which can be obtained from the whole vehicle model in step S11.

[0132] It is understood that the embodiments of the present invention provide a simulation method for steering wheel vibration, which can establish a whole vehicle simulation model and import road excitation loads under different working conditions. In the whole vehicle simulation model, the gear-rack constraint relationship of the steering system, the suspension-tire constraint relationship of the chassis system, and the constraint relationship of the body-CCB system on the steering system are considered. In the extraction of road excitation loads, three methods for extracting road loads are proposed, which fully consider the modeling of the steering system under the whole vehicle and are more comprehensive and accurate than previous steering system modeling methods.

[0133] like Figure 2The diagram shown illustrates a structural schematic of an embodiment of a steering wheel vibration simulation system provided by the present invention. (In conjunction with...) Figures 3 to 9 As shown, the steering wheel vibration simulation system 1 includes:

[0134] Subsystem model building unit 10 is used to build finite element models of the steering system, chassis system and body system based on the vehicle structure.

[0135] The vehicle model building unit 11 is used to assemble the finite element models of the steering system, chassis system, and body system into a finite element model of the whole vehicle according to the interconnection relationship between the various systems in the whole vehicle. In the vehicle model building unit 11, bolt connections are simulated using RBE2 elements, and bushing connections are simulated using Cbush elements. The interconnection relationship further includes the gear-rack constraint relationship of the steering system, the suspension-tire constraint relationship of the chassis system, and the constraint relationship between the body and CCB system on the steering system.

[0136] The road surface excitation load extraction unit 12 is used to extract the road surface excitation load under different working conditions;

[0137] The steering wheel vibration response acquisition unit 13 is used to input the road excitation load into the finite element model of the whole vehicle, perform simulation calculation processing, and obtain steering wheel vibration response information.

[0138] The subsystem model establishment unit 10 includes a steering system model establishment unit 100, a chassis system model establishment unit 101, and a body system model establishment unit 102.

[0139] Furthermore, the steering system model building unit 100 includes:

[0140] The steering component mesh model building unit 103 is used to generate mesh models of various components in the steering system, such as the steering tie rod, steering gear, steering column, and steering wheel, according to the finite element modeling method.

[0141] The connection processing unit 104 is used to connect the steering tie rod, steering gear, steering column and steering wheel using simulation units, wherein the ball joint between the steering tie rod and the steering gear is simulated using RBE2 units; the gear-rack meshing in the steering gear is simulated using MPC units; and the bending stiffness of the steering column is simulated using Cbush units.

[0142] The local coordinate system establishment unit 105 is used to establish a local coordinate system. The direction from the six o'clock position to the twelve o'clock position of the steering wheel is taken as the X direction of the local coordinate system, the Y direction of the whole vehicle is taken as the Y direction of the local coordinate system, and the direction of the steering column axis is taken as the Z direction of the local coordinate system.

[0143] Furthermore, the chassis system model building unit 101 includes:

[0144] Chassis component mesh model building unit 106 is used to generate mesh models of various components in the chassis system, such as the subframe, suspension, axle joints, tires, and stabilizer bars, according to the finite element modeling method.

[0145] The damper modeling unit 107 is used to model the damper, establish the mesh model of the damper outer cylinder and top rod, and use Cbush elements to simulate the connection between the two; the parameters in the X and Y directions characterize the bending characteristics of the damper, and the parameters in the Z direction characterize the displacement-force characteristics of the damper under tension and compression; for the TopMount at the top of the damper, Cbush elements are used to characterize its stiffness and damping characteristics.

[0146] Furthermore, the vehicle body system model building unit 102 includes:

[0147] Steering column support modeling unit 108 is used to perform detailed modeling of the steering column support according to the finite element modeling method;

[0148] Modeling unit 109 for the rest of the vehicle body is used to simulate the rest of the vehicle body using Plotel simplified units.

[0149] The road surface excitation load extraction unit 12 includes:

[0150] The first extraction unit 120 is used to obtain the road excitation load based on the road load file in the finite element software.

[0151] The second extraction unit 121 is used to perform FFT transformation on the time-domain curve to obtain the frequency-domain curve based on the road surface feature data obtained by road spectrum scanning, and to obtain the load of each wheel.

[0152] The third extraction unit 122 is used to obtain the force and torque in six directions of each wheel center by inverse matrix method, thereby obtaining the wheel center load of each wheel.

[0153] The third extraction unit 122 further includes:

[0154] The sensing signal acquisition unit 23 is used to arrange m triaxial accelerations around the shaft joint for different working conditions and measure the acceleration signals of the m sensors.

[0155] Hammering measurement unit 124 is used to disassemble the wheel in the finite element model of the chassis system, keep the m triaxial accelerations arranged around the axle joint unchanged, select n points on the brake disc, use the hammering method to measure the transfer function from the n points to the m accelerations to form the transfer function matrix [H], and record the coordinates of each impact point relative to the wheel center.

[0156] Wheel center load calculation unit 125 is used to obtain the wheel center load using the following inverse matrix formula:

[0157] F = [H] -1 A;

[0158] Where [H] is the measured transfer matrix, [H] -1 For its generalized inverse, [H] -1 It is a 3n×3m matrix, where n and m are the number of tapping points and sensors, respectively, and F is a 3n×1 row vector;

[0159] Wheel center torque acquisition unit 126 is used to obtain the force and torque in six directions of the axle head according to the geometric reduction principle based on the geometric matrix, using the following formula.

[0160]

[0161]

[0162] Where F is the aforementioned 3n×1 row vector, [C] is the geometric reduction matrix, and x, y, z are the coordinates of the aforementioned striking point relative to the wheel center; The row vectors are 6×1, representing the three translational forces and three rotational torques of the wheel center.

[0163] The steering wheel vibration response acquisition unit 13 further includes:

[0164] The first processing unit 130 is used to calculate the cross spectrum of the four-wheel loads based on the four-wheel load signals collected from the road spectrum, and import the loads into the whole vehicle model for calculation to obtain steering wheel vibration response information.

[0165] The second processing unit 131 is used to calculate the vibration response of the steering wheel according to the formula after independently determining the forces and moments in six directions at the four wheel centers:

[0166]

[0167] Wherein, FRF is the transfer function from the four wheel centers to the steering wheel.

[0168] Implementing the embodiments of the present invention has the following beneficial effects:

[0169] This invention provides a simulation method and system for steering wheel vibration, which involves establishing a whole vehicle simulation model and importing road surface excitation loads under different working conditions. The whole vehicle simulation model considers the gear-rack constraint relationship of the steering system, the suspension-tire constraint relationship of the chassis system, and the constraint relationship between the body and CCB system on the steering system. In extracting road surface excitation loads, three methods for extracting road surface loads are proposed, fully considering the modeling of the steering system under the whole vehicle, making it more comprehensive and accurate than previous steering system modeling methods.

[0170] In embodiments of the present invention, steering wheel vibration can be predicted in the early stages of vehicle development, and the vibration of the steering wheel under different road surfaces can be predicted. Based on this, the optimization of steering wheel vibration can be carried out in the early stages of project research and development, and the development cycle can be shortened.

[0171] In this embodiment of the invention, road surface excitation load extraction under different working conditions is considered, making the load input of the invention closer to the characteristics of actual vehicle driving conditions.

[0172] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0173] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0174] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A steering wheel vibration simulation method characterized by comprising: The method comprises the following steps: Step S10, based on the whole vehicle structure, establishing finite element models of the steering system, the chassis system and the vehicle body system; Step S11, according to the mutual connection relationship between each system in the whole vehicle, assembling the finite element models of the steering system, the chassis system and the vehicle body system into a finite element model of the whole vehicle; Step S12, extracting road excitation loads under different working conditions; Step S13, inputting the road excitation loads into the finite element model of the whole vehicle, performing simulation calculation processing, and obtaining steering wheel vibration response information; The step S11 further comprises: According to the mutual connection relationship of each system in the real vehicle, the steering system, the chassis system and the vehicle body system are assembled into a whole vehicle model, wherein the bolt connection is simulated by RBE2 unit in the model, and the bushing connection is simulated by Cbush; the mutual connection relationship further comprises the constraint relationship of the gear-rack of the steering system, the constraint relationship of the suspension-tire of the chassis system, and the constraint relationship of the vehicle body-steering column support on the steering system.

2. The method of claim 1, wherein, The step S10 comprises the following steps of establishing a finite element model of the steering system: According to the finite element modeling method, a grid model of each component of the steering pull rod, the steering gear, the steering column and the steering wheel in the steering system is generated; The steering pull rod, the steering gear, the steering column and the steering wheel are connected by using simulation units, wherein the spherical hinge between the steering pull rod and the steering gear is simulated by RBE2 unit; the meshing of the gear-rack in the steering gear is simulated by MPC unit; the bending stiffness of the steering column is simulated by Cbush unit; A local coordinate system is established, the direction from the six o'clock position to the twelve o'clock position of the steering wheel is taken as the X direction of the local coordinate system, the Y direction of the whole vehicle is taken as the Y direction of the local coordinate system, and the axis direction of the steering column is taken as the Z direction of the local coordinate system.

3. The method of claim 1, wherein, The step S10 comprises the following steps of establishing a finite element model of the chassis system: According to the finite element modeling method, a grid model of each component of the subframe, the suspension, the axle joint, the tire and the stabilizer bar in the chassis system is generated; The shock absorber is modeled, the grid models of the outer cylinder and the top rod of the shock absorber are established, and the connection between the two is simulated by Cbush unit; wherein the parameters of X and Y directions represent the bending characteristics of the shock absorber, and the parameter of Z direction represents the displacement-force characteristics of the shock absorber when it is pulled and pressed; for the top of the shock absorber, the stiffness and damping characteristics are represented by Cbush unit; The step S10 comprises the following steps of establishing a finite element model of the vehicle body system: the steering column support is modeled in detail according to the finite element modeling method; For the rest of the vehicle body, Plotel simplified unit is used for simulation.

4. The method of claim 3, wherein In the step S12, the road excitation load is extracted by any one of the following methods: According to the road load file in the finite element software, the road excitation load is obtained; According to the road feature data obtained by road spectrum scanning, the time domain curve is transformed into frequency domain curve by FFT to obtain the load of each wheel; The six direction forces and torques of the wheel center are inversely solved by inverse matrix method, so as to obtain the wheel center load of each wheel.

5. The method of claim 4, wherein, The step of inversely obtaining the six directional forces and moments of each wheel hub by the inverse matrix method further comprises: Arranging m three-way acceleration sensors around the axle joint under different working conditions to measure the acceleration signals of the m sensors; Disassembling the wheels in the chassis system finite element model, keeping the m three-way acceleration sensors arranged around the axle joint unchanged, selecting n points on the brake disc, and measuring the transfer functions from the n points to the m acceleration signals by the hammering method to form a transfer matrix [H], and recording the coordinates of each knocking point relative to the wheel hub; The wheel hub load is obtained by the following inverse matrix formula: ； wherein, is the measured transfer matrix, is the generalized inverse thereof, is the matrix, n and m are the number of striking points and sensors, respectively, F is a row vector of According to the geometric matrix according to the geometric reduction principle, the six directional forces and moments of the shaft head are obtained by the following formula : ； ； where F is the aforementioned row vector, is a geometric reduction matrix, x, y, z are the coordinates of the recorded knock point relative to the wheel center; is row vector, respectively, representing the three translational forces and three rotational moments of the wheel center.

6. The method of claim 4, wherein, The step S13 further comprises: According to the four-wheel load signals collected by the road spectrum, the cross spectrum of the four-wheel load is calculated, the load is introduced into the vehicle model for calculation, and the steering wheel vibration response information is obtained; after the six directional forces and moments of the four wheel hubs are independently solved, the steering wheel vibration response is solved according to the formula: ； Wherein, FRF is the transfer function from the four wheel hubs to the steering wheel.

7. A steering wheel vibration simulation system characterized by comprising: It comprises: A subsystem model establishing unit, configured to establish finite element models of a steering system, a chassis system and a vehicle body system based on a whole vehicle structure; A whole vehicle model establishing unit, configured to assemble the finite element models of the steering system, the chassis system and the vehicle body system into a finite element model of the whole vehicle according to mutual connection relationships between systems in the whole vehicle; A road excitation load extracting unit, configured to extract road excitation loads under different working conditions; A steering wheel vibration response obtaining unit, configured to input the road excitation loads into the finite element model of the whole vehicle for simulation calculation and processing, and obtain steering wheel vibration response information. In the whole vehicle model establishing unit, bolt connections are simulated by RBE2 units and bush connections are simulated by Cbush; the mutual connection relationships further include constraint relationships of a gear-rack of the steering system, constraint relationships of a suspension-tire of the chassis system, and constraint relationships of a vehicle body-steering column support on the steering system.

8. The system of claim 7, wherein, The subsystem model establishing unit comprises a steering system model establishing unit, which comprises: A steering component grid model establishing unit, configured to generate grid models of steering pull rods, a steering gear, a steering column and a steering wheel in the steering system according to a finite element modeling method; A connection processing unit, configured to connect the steering pull rods, the steering gear, the steering column and the steering wheel by simulation units, wherein a spherical hinge between the steering pull rods and the steering gear is simulated by an RBE2 unit; meshing of a gear-rack in the steering gear is simulated by an MPC unit; the steering column is simulated by a Cbush unit in terms of bending stiffness; A local coordinate system establishing unit, configured to establish a local coordinate system, taking a direction from a six o'clock position to a twelve o'clock position of the steering wheel as an X direction of the local coordinate system, taking a whole vehicle Y direction as a Y direction of the local coordinate system, and taking a steering column axis direction as a Z direction of the local coordinate system.

9. The system of claim 7, wherein, The subsystem model establishing unit comprises a chassis system model establishing unit and a vehicle body system model establishing unit, and the chassis system model establishing unit comprises: A chassis component mesh model establishing unit is configured to generate mesh models of each component in the chassis system, including a subframe, a suspension, an axle joint, a tire, and a stabilizer bar, according to a finite element modeling method; A shock absorber modeling unit is configured to model the shock absorber, establish mesh models of a shock absorber outer cylinder and a top rod, and simulate the connection between the two by using a Cbush unit; wherein parameters in the X and Y directions represent the bending characteristics of the shock absorber, and the parameter in the Z direction represents the displacement-force characteristics of the shock absorber when being pulled or pressed; for the top of the shock absorber, the Cbush unit is used to represent the stiffness and damping characteristics thereof; The vehicle body system model establishing unit comprises: A steering column support modeling unit is configured to model the steering column support in detail according to the finite element modeling method; A vehicle body remaining part modeling unit is configured to simulate the remaining part of the vehicle body by using a Plotel simplified unit.

10. The system of claim 9, wherein, The road excitation load extracting unit comprises: A first extracting unit is configured to obtain road excitation loads according to a road load file in the finite element software; A second extracting unit is configured to obtain the loads of each wheel by performing FFT transformation on the time-domain curve to obtain a frequency-domain curve according to road feature data scanned from a road profile; A third extracting unit is configured to obtain the hub loads of each wheel by inversely solving the six-direction forces and moments of each hub by using an inverse matrix method; The third extracting unit further comprises: A sensing signal obtaining unit is configured to measure the acceleration signals of m three-direction acceleration sensors arranged around the axle joint under different working conditions; A hammering measurement unit is configured to remove the wheels in the chassis system finite element model, keep the m three-direction acceleration sensors arranged around the axle joint unchanged, select n points on the brake disc, measure the transfer functions from the n points to the m acceleration signals to form a transfer matrix [H], and record the coordinates of each knocking point relative to the hub; A hub load calculating unit is configured to obtain the hub loads by using the following inverse matrix formula: ； wherein, is the measured transfer matrix, is the generalized inverse thereof, is the matrix, n and m are the number of striking points and sensors, respectively, F is a row vector of The wheel center moment obtaining unit is used to obtain the six directional forces and moments of the shaft head according to the geometric reduction principle according to the geometric matrix by the following formula : ； ； where F is the aforementioned row vector, is a geometric reduction matrix, x, y, z are the coordinates of the recorded knock point relative to the wheel center; is row vector, respectively, representing the three translational forces and three rotational moments of the wheel center; The steering wheel vibration response obtaining unit further comprises: A first processing unit is configured to calculate the cross spectrum of the four-wheel loads according to the four-wheel load signals collected from the road profile, import the loads to the whole vehicle model for calculation, and obtain the steering wheel vibration response information; A second processing unit is configured to calculate the steering wheel vibration response according to the formula after independently calculating the six-direction forces and moments of the four hubs: ； wherein FRF is the transfer function from the four hubs to the steering wheel.

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