Commercial vehicle front axle rigidity analysis and evaluation method, system, equipment and medium

Abstract

The invention belongs to the technical field of commercial vehicle front axle analysis, and particularly relates to a commercial vehicle front axle rigidity analysis and evaluation method, system, device and medium, and the method comprises the steps: building a front axle assembly model, defining a coordinate system, and setting two groups of reference points in the model; applying constraint conditions for simulating the assembly state of the whole vehicle; a vertical step load and a composite brake load are respectively applied to a wheel grounding point, and impact and brake working conditions are simulated; the camber angle variation is obtained by calculating the coordinate change of the first group of reference points, and the vertical rigidity is evaluated; and based on the coordinate change of the second group of reference points, respectively calculating a bending deformation angle variable quantity and a torsional deformation angle variable quantity, and evaluating longitudinal bending and torsional rigidity. According to the method, by establishing evaluation indexes, rigidity is decomposed into vertical bending resistance, longitudinal bending resistance and torsion resistance for measurement. According to the method, the problems of rigidity deformation, braking deviation, steering interference and the like are clearly related, a design basis is provided for front axle structure optimization, and the operation stability and safety of the whole vehicle are enhanced.

Description

Technical Field

[0001] This invention belongs to the field of commercial vehicle front axle analysis technology, specifically relating to a method, system, equipment, and medium for analyzing and evaluating the stiffness of a commercial vehicle front axle. Background Technology

[0002] Currently, in the commercial vehicle industry, front axle products are mainly of the "I" shape and are produced by forging. However, there are significant differences in the detailed shape of the cross-section among various axle manufacturers. There are "Z" shaped cross-sections, asymmetrical "I" shaped cross-sections, and hollow structures in the middle of the front beam. In addition to considering the load-bearing reliability of the front beam, the stiffness of the front axle has a significant impact on the vehicle's positioning parameters, which in turn affects the overall vehicle handling and stability.

[0003] In the front axle stiffness analysis of related technologies, constructing a three-dimensional model based on two-dimensional drawings can easily lead to distortions in the simulation of the assembly fit between the steering knuckle and the front beam, and between the steering rod and the steering knuckle. During the wheel end structure processing, retaining the wheel end results in model redundancy, increasing computational load and convergence difficulty, causing significant deviations between the deformation patterns in the simulation and the actual front axle, thus failing to reflect the actual stiffness characteristics.

[0004] In related technologies, the selection of reference points often involves mixing points used for vertical deformation monitoring with those used for longitudinal deformation monitoring. This leads to interference between the displacement data of the two types of points during loading, making it impossible to accurately extract deformation information in a single stiffness dimension. For example, if the center point of the leaf spring seat and the end face point of the rod unit are combined into one set of data, the longitudinal bending displacement under braking conditions will be superimposed on the vertical stiffness analysis data, resulting in a deviation in stiffness evaluation and making it difficult to accurately identify the weak points in the stiffness of the front axle under different operating conditions.

[0005] Related technologies also set the mating end faces of the front beam and steering knuckle as fixed constraints, without setting specific constraints on the leaf spring seat. This results in longitudinal displacement of the front axle exceeding the actual range under braking conditions, making it impossible to realistically simulate the limiting effect of the leaf spring on the front axle. The unreasonable setting of the constraint conditions causes the deformation mode and load transfer path in the simulation to be inconsistent with the actual situation, rendering the stiffness analysis results useless. Summary of the Invention

[0006] This invention provides a method for analyzing and evaluating the front axle stiffness of commercial vehicles. The method determines the evaluation indicators of vertical and longitudinal stiffness, simulates deformation under actual working conditions, simplifies the model to improve simulation efficiency, optimizes the front axle stiffness, and provides data support for evaluating the overall vehicle handling performance.

[0007] The methods include: S101: Construct a three-dimensional solid assembly model of the front axle of a commercial vehicle, and assemble rod units at the ends of the steering knuckles on both sides of the front axle; define the position of the front axle in a spatial rectangular coordinate system, with the origin 0 of the coordinate system being the intersection of the front-rear symmetry plane, the left-right symmetry plane and the leaf spring surface of the front axle, the X-axis pointing in the opposite direction of vehicle travel, the Y-axis pointing to the right side of the vehicle, and the Z-axis pointing vertically upward; S102: Establish reference points on the model, including: establishing a first set of reference points at both ends of the rod unit; and establishing a second set of reference points at the center point of the front axle kingpin, the center point of the leaf spring seat, and the intersection of the end of the front beam and the center line of the kingpin. S103: Set constraint relationships, including: coupling constraints between the left and right wheel contact points and the steering knuckle axle head; hinge constraints between the front beam and the steering knuckle mating end face; binding constraints between the steering tie rod arm, steering knuckle arm and steering knuckle; ball joint connection between the steering tie rod arm, tie rod assembly and steering knuckle arm, and tie rod assembly; coupling the coordinate system center point 0 with the beam element and constraining the Y-axis displacement degree of freedom of the beam element at the center of the left and right symmetry planes of the front axle; fixing the ball center point at the front end of the tie rod assembly; coupling the leaf spring seat center point with the leaf spring surface and constraining the X and Z axis displacement degrees of freedom and the rotational degree of freedom around the Y-axis; S104: Based on the constraint of S103, a stepped load along the positive Z-axis is applied to the contact points of the left and right wheels to simulate the impact condition; the change in wheel camber angle Δα is calculated by the coordinate change before and after loading of the first set of reference points, and the change in camber angle Δα is used as the vertical stiffness evaluation index. S105: Based on the constraint of S103, the braking condition is simulated by simultaneously applying the support force along the positive Z-axis and the stepped braking force along the positive X-axis at the contact points of the left and right wheels; by changing the projection coordinates of the kingpin center point and the leaf spring seat center point in the second set of reference points on the XOY plane, the change in the bending deformation angle Δβ of the front axle around the Z-axis is calculated, and Δβ is used as the evaluation index of longitudinal bending stiffness. S106: Based on the same braking condition in S105 and the constraints in S103, the change in the torsional deformation angle Δγ of the front axle around the Y-axis is calculated by changing the projection coordinates of the intersection point of the front beam ends in the XOZ plane in the second set of reference points. Δγ is used as the evaluation index of longitudinal torsional stiffness.

[0008] It should be further explained that S101 specifically includes the following steps: S1011: Obtain the 3D data of the left steering knuckle, right steering knuckle, left steering tie rod arm, right steering tie rod arm, steering knuckle arm, steering tie rod assembly, front beam, and tie rod assembly of the commercial vehicle front axle. Construct 3D solid models of each component based on the 3D data, and then assemble them sequentially according to the actual assembly and connection relationship of each component to form the initial solid assembly model of the front axle. S1012: In the initial solid assembly model of the front axle, cylindrical assembly surfaces are selected at the ends of the left and right steering knuckles, and the two ends of the rod unit are coaxially assembled with the cylindrical assembly surfaces of the steering knuckle ends; the wheel end structure in the model is removed to obtain the simplified solid assembly model of the front axle. S1013: In the front axle solid assembly model, determine the front and rear symmetry planes, left and right symmetry planes, and leaf spring surface of the front axle. Take the intersection point of these three planes as the origin 0 of the spatial rectangular coordinate system. Set the direction pointing in the opposite direction of vehicle travel as the positive X-axis, the direction facing the right side of the vehicle in the direction of travel as the positive Y-axis, and the vertical upward direction as the positive Z-axis, thus completing the position definition of the front axle in this coordinate system.

[0009] It should be further explained that S102 specifically includes the following steps: S1021: Locate the center position on the circular end faces at both ends of the rod element, and generate two reference points at the center using a 3D modeling tool to form the first set of reference points, denoted as A0 and B0; S1022: Extract the axis of the front axle kingpin and the axis of the steering knuckle head and determine the intersection of the two axes. Extract the geometric center of the leaf spring seat bearing surface as the center point of the leaf spring seat and classify the center point as the first subgroup of the second set of reference points. S1023: Extend the kingpin axis to intersect with the upper and lower end faces of the front beam end, and obtain four intersection points as the intersection points of the front beam end and the kingpin center line, which are classified as subgroup two of the second group of reference points.

[0010] It should be further explained that S103 specifically includes the following steps: S1031: In the simulation model, the cylindrical contact surface between the left wheel ground contact point and the left steering knuckle axle head is set as a coupling constraint, and the cylindrical contact surface between the right wheel ground contact point and the right steering knuckle axle head is set as a coupling constraint; the annular mating end faces of the front beam with the left and right steering knuckles are set as hinge constraints; the mounting flange surfaces of the left and right steering tie rod arms, the right steering tie rod arms, and the steering knuckle arms are set as binding constraints with the corresponding mounting surfaces of the left and right steering knuckles; the ball joint seats of the left and right steering tie rod arms, the ball joints at both ends of the tie rod assembly are set as ball joint connections with the ball joint holes of the steering knuckle arms and the ball joint seats of the tie rod assembly, respectively. S1032: In the simulation model, select the beam element at the center of the left and right symmetry planes of the front axle, establish a coupling relationship between the origin 0 of the coordinate system and the center section of the beam element, and constrain the displacement degree of freedom of the beam element in the Y-axis direction; locate the center point of the ball at the front end of the steering tie rod assembly, set the center point as a fixed constraint, and restrict its displacement degree of freedom in the X, Y, and Z directions and rotational degree of freedom around the three coordinate axes; S1033: In the simulation model, extract the center point of the leaf spring seat, establish coupling constraints between the two center points and the leaf spring surface respectively, constrain the displacement degree of freedom of the center point of the leaf spring seat in the X-axis and Z-axis directions, and constrain its rotational degree of freedom around the Y-axis.

[0011] It should be further explained that S104 specifically includes the following steps: S1041: Define the load parameters for the impact condition, determine that the load application direction is the positive Z-axis direction, set the initial load value, maximum load value and load step size, and determine the stabilization time for each load step; S1042: Based on the constraints and defined load parameters of S103, apply a stepped load along the positive Z-axis simultaneously at the contact points of the left and right wheels until the set maximum load value is reached. S1043: Acquire the initial coordinates of the first set of reference points in S102 before loading, according to Establish the relationship between the vertical stiffness of the front axle and the deformation around the X-axis under impact conditions, and determine the analysis process of deformation through the change of coordinates of the reference point; S1044: Substitute the acquired initial coordinates and the real-time coordinates of the reference point after each load step stabilization into... Calculate the initial tilt angle α0° and the tilt angle αn° corresponding to each load step, and then obtain the tilt angle change Δα° = α n °-α0°; S1045: Establish the mapping relationship between the change in camber angle Δα and the corresponding load, determine Δα as the evaluation index of the front axle vertical stiffness, and form vertical stiffness characteristic data under impact conditions.

[0012] It should be further explained that S105 specifically includes the following steps: S1051: Define the load parameters for braking conditions, set the vertical support force along the positive Z-axis to a constant value matching the full load state of the commercial vehicle, set the braking force along the positive X-axis to a stepped variation value, clarify the initial value, maximum value and load step size of the braking force, and determine the stable holding time of each load step. S1052: Based on the constraints of S103 and the parameters defined in S1051, a constant vertical support force in the positive Z-axis direction is applied synchronously at the contact points of the left and right wheels, and then a stepped braking force in the positive X-axis direction is applied step by step according to the set step size until the maximum braking force value is reached. S1053: Collect the initial projection coordinates of the kingpin center point and leaf spring seat center point in the second set of reference points in S102 onto the XOY plane before loading, and substitute them into... Calculate the initial bending angle β0°; S1054: After each braking load step stabilizes, acquire the real-time projected coordinates of the reference point in the XOY plane and substitute them into... Calculate the bending angle βn° under the corresponding load, and obtain the change in bending deformation angle through Δβ°=βn°β0°; S1055: Organize the braking force and Δβ value corresponding to each load step, establish the mapping relationship between the two, determine Δβ as the evaluation index of the longitudinal bending stiffness of the front axle, and form longitudinal bending stiffness characteristic data under braking conditions.

[0013] It should be further explained that S106 specifically includes the following steps: S1061: Lock the braking condition parameters of S105, and use its set constant value of vertical support force, braking force step parameters and load step stability holding time to determine the reference point for acquisition as the established front beam end intersection point. S1062: Based on the constraints of S103 and the locked braking condition parameters, the load application process of S105 is called synchronously to ensure the continuity and consistency of the braking condition. S1063: Load the initial coordinates of the reference point's projection onto the XOZ plane, and substitute them into... Calculate the initial torsional deformation angle γ0°; S1064: After each braking load step stabilizes, acquire the real-time projected coordinates of the reference point on the XOZ plane and substitute them into... Calculate the torsional deformation angle γ under the corresponding load. n °, the change in torsional deformation angle is obtained by Δγ°=γn°-γ0°; S1065: Organize the braking force and Δγ value corresponding to each load step, establish the mapping relationship between the two, determine Δγ as the evaluation index of the longitudinal torsional stiffness of the front axle, and form longitudinal torsional stiffness characteristic data under braking conditions.

[0014] This invention also provides a system for analyzing and evaluating the front axle stiffness of commercial vehicles, the system comprising: The model construction definition module is used to construct a three-dimensional solid assembly model of the front axle of a commercial vehicle, and to assemble rod units at the ends of the steering knuckles on both sides of the front axle; the position of the front axle is defined in a spatial rectangular coordinate system, with the origin 0 being the intersection of the front axle's front-rear symmetry plane, left-right symmetry plane, and leaf spring surface; the X-axis points in the opposite direction of vehicle travel, the Y-axis points to the right side of the vehicle, and the Z-axis is vertically upward; The reference point establishment module is used to establish reference points on the model, including: establishing a first set of reference points at both ends of the rod unit; and establishing a second set of reference points at the center point of the front axle kingpin, the center point of the leaf spring seat, and the intersection of the end of the front beam and the center line of the kingpin. The constraint setting module is used to set constraint relationships, including: coupling constraints between the left and right wheel contact points and the steering knuckle axle head; hinge constraints between the front beam and the steering knuckle mating end face; binding constraints between the steering tie rod arm, steering knuckle arm, and steering knuckle; ball joint connections between the steering tie rod arm, tie rod assembly, steering knuckle arm, and tie rod assembly; coupling the coordinate system center point 0 with the beam element and constraining the Y-axis displacement degree of freedom of the beam element at the center of the left and right symmetry planes of the front axle; fixing the center point of the front ball of the tie rod assembly; coupling the leaf spring seat center point with the leaf spring surface and constraining the X and Z axis displacement degrees of freedom and the rotational degree of freedom around the Y-axis; The vertical stiffness analysis module, based on the S103 constraint, applies a stepped load along the positive Z-axis at the contact points of the left and right wheels to simulate impact conditions; it calculates the change in wheel camber angle Δα by changing the coordinates of the first set of reference points before and after loading, and uses the change in camber angle Δα as the evaluation index of vertical stiffness. The longitudinal bending stiffness analysis module, based on the S103 constraint, simultaneously applies a support force along the positive Z-axis and a stepped braking force along the positive X-axis at the contact points of the left and right wheels to simulate braking conditions. By changing the projection coordinates of the kingpin center point and the leaf spring seat center point in the second set of reference points on the XOY plane, the change in the bending deformation angle Δβ of the front axle around the Z-axis is calculated, and Δβ is used as the evaluation index of longitudinal bending stiffness. The longitudinal torsional stiffness analysis module, based on the same braking condition S105 and the constraint S103, calculates the change in the torsional deformation angle Δγ of the front axle around the Y-axis by changing the projection coordinates of the intersection point of the front beam end in the XOZ plane in the second set of reference points, and uses Δγ as the evaluation index of longitudinal torsional stiffness.

[0015] According to another embodiment of this application, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the commercial vehicle front axle stiffness analysis and evaluation method.

[0016] According to another embodiment of this application, a storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the commercial vehicle front axle stiffness analysis and evaluation method.

[0017] As can be seen from the above technical solutions, the present invention has the following advantages: The commercial vehicle front axle stiffness analysis and evaluation method provided by this invention collects dimensional data of the main components of the front axle through 3D scanning and mapping, and completes the component assembly step by step according to the actual vehicle installation sequence. A rod unit is coaxially assembled at the end of the steering knuckle axle head to replace the wheel end structure, preserving the force transmission characteristics of the steering knuckle axle head. A spatial rectangular coordinate system is defined based on the intersection of the front axle's front-rear symmetry plane, left-right symmetry plane, and leaf spring surface to ensure that the model's spatial posture is consistent with the actual vehicle installation state.

[0018] This invention subdivides reference point groups according to stiffness analysis type. The first group is set at the center of the end faces of both ends of the rod unit, and the second group is set according to longitudinal bending and longitudinal torsion. All reference points are located based on the inherent geometric characteristics of the components and establish a rigid association with the corresponding components. Constraint types are precisely matched according to the assembly relationship of each component: coupling constraints are set between the wheel contact point and the steering knuckle axle head; hinge constraints are set between the front beam and the steering knuckle; binding constraints are set between the steering rod and the steering knuckle; and ball joint connections are set between the steering system rods. Targeted benchmark constraints are set to constrain the Y-axis displacement of the beam unit, fix the center point of the front ball of the tie rod, and constrain the X / Z-axis displacement and rotation around the Y-axis of the leaf spring seat, constructing a mechanical boundary consistent with the actual assembly. Load application strategies are designed for different working conditions: in the impact condition, a stepped vertical load in the positive Z-axis direction is applied simultaneously at the wheel contact point; in the braking condition, a constant vertical support force in the Z-axis direction and a stepped braking force in the positive X-axis direction are applied simultaneously. A stabilization holding time is set for each load step to ensure complete convergence of the front axle deformation. A direct correlation between stiffness indicators and overall vehicle performance is established. The change in wheel camber angle Δα is calculated based on the coordinate changes of reference points at both ends of the link unit; the change in bending angle around the Z-axis Δβ is calculated based on the XOY projection change of the kingpin / leaf spring seat center point; and the change in torsional angle around the Y-axis Δγ is calculated based on the XOZ projection change of the intersection point at the front beam ends. These evaluation indicators, correlated with overall vehicle performance, transform abstract stiffness characteristics into data that can be intuitively linked to driving safety. This allows front axle structure optimization to reflect key areas affecting wheel camber angle and braking bounce interference, improving the targeting and effectiveness of optimization efforts. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the 3D model and its spatial coordinates. Figure 2 This is a schematic diagram of the reference points and constraint relationships of the front axle model of the present invention; Figure 3 This is a schematic diagram illustrating the change in the vertical outward tilt angle of the present invention; Figure 4 This is a schematic diagram of the longitudinal deformation of the present invention around the Z-axis; Figure 5 This is a schematic diagram of the longitudinal deformation of the present invention around the Y-axis; Figure 6 Flowchart of the method for analyzing and evaluating the front axle stiffness of commercial vehicles; Figure 7 This is a schematic diagram of an electronic device.

[0021] Appendix Figure 1In the middle, 1-left steering knuckle, 2-left steering tie rod arm, 3-steering knuckle arm, 4-steering tie rod assembly, 5-front beam, 6-beam unit, 7-tie rod assembly, 8-right steering tie rod arm, 9-right steering knuckle, 10-rod unit. Detailed Implementation

[0022] like Figure 1 The diagram shows a combination of a three-dimensional solid assembly model of a commercial vehicle's front axle and a spatial rectangular coordinate system. The left steering knuckle 1 is located at the left end of the front axle and has a fork-shaped structure. Its inner end face is hinged to the left end face of the front beam 5, allowing it to rotate around the central axis of the mating end face. The outer axle head end is fixed to the left end of the rod unit 10 via coaxial assembly constraints. A virtual left wheel contact point (4.1) is defined on the outer side of the axle head. This left wheel contact point (4.1) is rigidly connected to the left steering knuckle 1 axle head through coupling constraints, used to transmit vertical loads under impact conditions and vertical support and braking forces under braking conditions. The intersection of the axis of the kingpin mounting hole and the axis of the steering knuckle axle head is the set kingpin center point (1.1), which is the main reference point for longitudinal bending stiffness analysis.

[0023] One end of the left steering tie rod arm 2 is fixed to the corresponding mounting surface of the left steering knuckle 1 by binding constraint, forming a rigid connection; the other end is adapted to the left end of the tie rod assembly 7 through ball joint connection, allowing multi-directional rotation around the ball joint center, forming the lateral force transmission path of the steering system; the assembly position ensures that the braking force energy is transmitted to the front beam 5 through the left steering knuckle 1 under braking conditions, and is the force transmission medium for the front axle torsion around the Y-axis and bending deformation around the Z-axis.

[0024] The steering knuckle arm 3 has an overall L-shaped structure. One end is positioned and assembled on the middle mounting surface of the left steering knuckle 1 and the right steering knuckle 9 through bolt holes, forming a rigid connection through binding constraints. The other end is connected to the rear end of the steering tie rod assembly 4 through a ball joint connection to transmit steering force. At the same time, it deforms synchronously with the steering knuckle under braking conditions. Its ball joint connection characteristics ensure the motion coordination of the steering system when the front axle deforms, without interfering with the deformation transmission in stiffness analysis.

[0025] The steering tie rod assembly 4 is arranged along the longitudinal direction of the front axle, i.e., the X-axis direction. The rear end is connected to the steering knuckle arm 3 via a ball joint. The front ball center point restricts all degrees of freedom through fixed constraints, simulating the locking of the front axle in the straight-line state by the vehicle steering control system. The rigid rod structure ensures the lateral attitude stability of the front axle under braking conditions and avoids additional displacement interference with the deformation quantification around the Z and Y axes. It is a key component in the constraint system that maintains the reference attitude of the front axle.

[0026] The front beam 5 is the load-bearing component of the front axle. It is a beam-shaped structure with an I-shaped cross-section. The left and right ends are connected to the mating end faces of the left steering knuckle 1 and the right steering knuckle 9 through hinge constraints. Leaf spring seats are symmetrically distributed on both sides of the beam. The center of the bearing surface of the leaf spring seat is the set center point of the leaf spring seat (2.1, 2.2). It is associated with the leaf spring surface through coupling constraints, which constrain the X and Z axis displacements and rotation around the Y axis. The micro-segment cut from the middle of the beam is the beam element 6. The central section is coupled with the origin 0 of the coordinate system and is the key carrier for constraining the Y axis displacement. The overall structure of the front beam 5 directly determines the vertical bending resistance, longitudinal bending resistance and torsional resistance of the front axle. It is the load-bearing component for stiffness analysis.

[0027] Beam element 6 is a micro-segment solid with a length of 30-50mm cut off at the center of the left and right symmetry planes of the front beam 5. The central section of beam element 6 coincides with the origin 0 of the coordinate system defined by S101. The Y-axis displacement degree of freedom is restricted by coupling constraints to simulate the lateral restraint of the front axle by the frame and suspension in the whole vehicle. This element only retains the load-bearing characteristics of the front beam 5, which simplifies the calculation complexity of constraint application and ensures that the center of mass of the front axle is relatively stationary with the center of mass of the whole vehicle, without affecting the load transfer and deformation law.

[0028] The tie rod assembly 7 is arranged laterally along the front axle, i.e., in the Y-axis direction. Its two ends are connected by ball joints to the left steering tie rod arm 2 and the right steering tie rod arm 8, respectively, forming the lateral stability structure of the steering system. The ball joint connection of the tie rod assembly 7 allows the lateral members to adapt to the angle change when the front axle undergoes bending or torsional deformation under braking and impact conditions, avoiding additional stress that may interfere with the stiffness analysis results. At the same time, it transmits lateral constraint force and maintains the coordination of deformation on both sides of the front axle.

[0029] The right steering tie rod arm 8 and the left steering tie rod arm 2 are symmetrically arranged. One end of the right steering tie rod arm 8 is fixed to the corresponding mounting surface of the right steering knuckle 9, and the other end is connected to the right end of the tie rod assembly 7 through a ball joint. The assembly position of the right steering tie rod arm 8 ensures that the force transmission path on the right side of the front axle is complete, so that the loads of the left and right wheel contact points (4.1, 4.2) can be synchronously transmitted to the front beam 5, ensuring the symmetry and authenticity of the front axle deformation around the Y-axis and Z-axis under braking conditions.

[0030] The right steering knuckle 9 and the left steering knuckle 1 are symmetrically arranged. The right steering knuckle 9 is located at the right end of the front axle. Its inner end face is hinged and constrained to the right end face of the front beam 5. Its outer axle head end is coaxially assembled with the right end of the rod unit 10. The right wheel grounding point (4.2) is virtually defined on the outer side of the axle head, and the load is transmitted through coupling constraint. The midpoint of the axis of the kingpin mounting hole of the right steering knuckle 9 is the set kingpin center point (1.2), which cooperates with the left kingpin center point (1.1) to form a symmetrical reference system for longitudinal bending stiffness analysis.

[0031] The rod element 10 is a cylindrical solid structure with a diameter consistent with the cylindrical diameter of the axle ends of the left steering knuckle 1 and the right steering knuckle 9. Both ends of the rod element 10 are coaxially assembled and constrained to the axle ends of the left steering knuckle 1 and the right steering knuckle 9, respectively, and the axis coincides with the axis of the steering knuckle axle ends. The rod element 10 is an auxiliary analysis structure used to support the first set of reference points. The rigid material of the rod element 10 ensures that the vertical bending deformation of the steering knuckle can be completely transmitted to the reference points, and the model does not have wheel end structures, which simplifies the simulation calculation. By changing the coordinates of the reference points at both ends of this component, the change in wheel camber angle Δα can be quantified, which is an auxiliary carrier for vertical stiffness analysis.

[0032] The commercial vehicle front axle stiffness analysis and evaluation method provided by this invention places the front axle in a spatial rectangular coordinate system for analysis. In the model preparation stage before simulation analysis, cylindrical rod elements are assembled at the end of the steering knuckle to assist in the front axle stiffness analysis, and concrete reference points are established to interpret the vertical and longitudinal stiffness of the front axle. Constraint relationships and boundary conditions are established according to the actual working conditions of the commercial vehicle front axle, and stepped loads are applied to conduct simulation analysis under both impact and braking conditions to obtain the evaluation index of front axle stiffness.

[0033] This invention establishes a front axle model in a spatial rectangular coordinate system to simulate the parameter changes of reference points related to front axle stiffness under different loads and working conditions. This enables efficient and accurate analysis of the stiffness characteristics of the front axle under different working conditions, thus obtaining a novel method for evaluating the front axle stiffness of commercial vehicles and laying a theoretical foundation for optimizing front axle stiffness.

[0034] The following describes in detail the method for analyzing and evaluating the front axle stiffness of commercial vehicles involved in this application. Specific details, such as particular system structures and technologies, are presented for illustrative purposes rather than limiting, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0035] It should be understood that, when used in this specification, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0036] The terms "one embodiment" or "some embodiments" used in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this application do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please see Figure 6 The diagram shows a flowchart of a method for analyzing and evaluating the front axle stiffness of a commercial vehicle in a specific embodiment. Figures 1 to 5 As shown, the method includes: S101: Construct a three-dimensional solid assembly model of the commercial vehicle front axle, and assemble rod units 10 at the ends of the steering knuckles (1, 9) on both sides of the front axle. Define the position of the front axle in a spatial rectangular coordinate system. The origin 0 of the coordinate system is the intersection of the front-rear symmetry plane, the left-right symmetry plane and the leaf spring surface of the front axle. The X-axis points in the opposite direction of vehicle travel, the Y-axis points to the right side of the vehicle, and the Z-axis is vertically upward.

[0039] In some embodiments, by collecting component size data and modeling according to actual assembly relationships, the constructed front axle solid assembly model can completely replicate the structural form and connection relationship of the real front axle; the coaxial assembly of the rod unit 10 ensures that it can synchronously follow the movement of the steering knuckle, providing a stable carrier for stiffness analysis.

[0040] S101 specifically includes the following steps: S1011: Obtain the 3D data of the left steering knuckle 1, right steering knuckle 9, left steering tie rod arm 2, right steering tie rod arm 8, steering knuckle arm 3, steering tie rod assembly 4, front beam 5, and tie rod assembly 7 of the commercial vehicle front axle. Construct 3D solid models of each component based on the 3D data, and then assemble them sequentially according to the actual assembly and connection relationship of each component to form the initial solid assembly model of the front axle.

[0041] In some embodiments, three-dimensional information of the front axle components, including the left steering knuckle 1, right steering knuckle 9, left steering tie rod arm 2, right steering tie rod arm 8, steering knuckle arm 3, steering tie rod assembly 4, front beam 5, and tie rod assembly 7, is collected. This includes information such as the mounting hole positions of the steering knuckle arm 3 on the left steering knuckle 1 and the distribution dimensions of the leaf spring seats on the front beam 5. Based on this information, a solid model of each component is created using a 3D modeling tool. For example, the model of the steering tie rod assembly 4 needs to match its rod length with the interface dimensions of the ball joints at both ends.

[0042] According to the actual vehicle installation connection method, install the steering knuckle arm 3 to the corresponding installation position of the left steering knuckle 1, install the left steering tie rod arm 2 to the corresponding interface of the left steering knuckle 1, and then assemble the assembled left steering knuckle 1 side component with the left end of the front beam 5. Similarly, complete the assembly of the right steering knuckle 9 side component with the right end of the front beam 5. Finally, the initial physical assembly model of the front axle is obtained with the connection relationship of each component consistent with the actual situation.

[0043] S1012: In the initial solid assembly model of the front axle, cylindrical assembly surfaces are selected at the ends of the left steering knuckle 1 and the right steering knuckle 9, respectively. The two ends of the rod unit 10 are coaxially assembled with the cylindrical assembly surfaces of the steering knuckle ends. The wheel end structure in the model is removed to obtain the simplified solid assembly model of the front axle.

[0044] In some embodiments, in the initial solid assembly model of the front axle, the cylindrical surface at the axle end of the left steering knuckle 1 that mates with the wheel end is located, and the diameter and axis orientation of this cylindrical surface are recorded. A similar cylindrical surface is located at the axle end of the right steering knuckle 9. A cylindrical solid model of the linkage unit 10 is prepared, with its diameter matching the diameter of the cylindrical surface at the steering knuckle axle end. One end of the cylindrical surface of the linkage unit 10 is coaxially fitted with the cylindrical surface at the axle end of the left steering knuckle 1, and the other end is coaxially fitted with the cylindrical surface at the axle end of the right steering knuckle 9, completing the assembly of the linkage unit 10. The solid structure corresponding to the wheel end is selected in the model and deleted from the current model, resulting in a simplified solid assembly model of the front axle retaining only the main components of the front axle and the linkage unit 10.

[0045] S1013: In the front axle solid assembly model, determine the front and rear symmetry planes, left and right symmetry planes, and leaf spring surface of the front axle. Take the intersection point of these three planes as the origin 0 of the spatial rectangular coordinate system. Set the direction pointing in the opposite direction of vehicle travel as the positive X-axis, the direction facing the right side of the vehicle in the direction of travel as the positive Y-axis, and the vertical upward direction as the positive Z-axis, thus completing the position definition of the front axle in the coordinate system.

[0046] In some embodiments, in the front axle solid assembly model, using the planar generation function of a 3D modeling tool, the longitudinal center plane of the front beam 5 is used as the front-rear symmetry plane of the front axle. A plane perpendicular to the front-rear symmetry plane and passing through the transverse midpoint of the front beam 5 is used as the left-right symmetry plane. The plane containing the leaf spring seat is used as the leaf spring surface. Using the tool's intersection detection function, the point where these three planes intersect is found, and this point is set as the origin 0 of the spatial rectangular coordinate system. Then, the direction opposite to the vehicle's travel is defined as the positive X-axis, the right side facing the travel direction is defined as the positive Y-axis, and the direction perpendicular to the horizontal plane upwards is defined as the positive Z-axis, thus determining the three axial directions of the coordinate system. The front axle solid assembly model is then positioned within this coordinate system. This directly corresponds to the actual attitude changes of the vehicle, ensuring that the stiffness analysis results reflect the actual vehicle performance.

[0047] S102: Establish reference points on the model, including: establishing a first set of reference points at both ends of the rod element 10 (for vertical stiffness analysis); establishing a second set of reference points at the center points of the front axle kingpin (1.1, 1.2), the center points of the leaf spring seat (2.1, 2.2), and the intersection points of the ends of the front beam 5 and the kingpin center line (8.1, 8.2, 9.1, 9.2).

[0048] In some embodiments, the first set of reference points is rigidly bound to the rod unit 10, which is coaxially assembled with the steering knuckle. The vertical bending deformation of the steering knuckle is directly transmitted to the rod unit, thereby causing the reference points to displace. The coordinate changes of the reference points can directly reflect the deformation state of the steering knuckle. Subgroup one of the second set of reference points is rigidly associated with the steering knuckle and the front beam, respectively. The relative bending deformation of the steering knuckle and the front beam is reflected as the relative displacement of their reference points. Subgroup two is located directly at the end of the front beam. The torsional deformation of the front beam directly causes the spatial position change of these intersection points. The positions of all reference points are determined based on the geometric characteristics of the front axle itself, ensuring that the displacement changes can accurately map the stiffness-related deformation of the front axle.

[0049] S102 specifically includes the following steps: S1021: Locate the center position on the circular end faces at both ends of the rod element 10, and generate two reference points at the center using a 3D modeling tool to form the first set of reference points, denoted as A0 and B0; In some embodiments, the assembled rod unit 10 is selected, with both ends being circular end faces that match the steering knuckle shaft head. Three non-collinear feature points are selected on the edge of each end face, and after drawing an auxiliary circle, the center position is determined. The center of the circle is the center of the end face.

[0050] Use the point generation function of the tool to create a reference point at the center. The center of the left end face of the rod element is recorded as A0, and the right end face as B0. The two reference points are rigidly associated with the rod element 10 to ensure synchronous displacement during subsequent deformation.

[0051] S1022: Extract the axis of the front axle kingpin and the axis of the steering knuckle axle head, and determine the intersection of the two axes as the kingpin center point (1.1, 1.2). Extract the geometric center of the leaf spring seat bearing surface as the leaf spring seat center point (2.1, 2.2). Assign the above four center points to subgroup one of the second group of reference points. In some embodiments, the kingpin mounting hole and the steering knuckle axle head of the left steering knuckle 1 are located in the three-dimensional model. The axis of the mounting hole is extracted as the left kingpin axis by the hole wall features, and the axis of the steering knuckle is extracted as the wheel end center line by the axle wall features. The intersection of the two axes is the left kingpin center point (1.1).

[0052] Using the same method, the axis of the kingpin mounting hole of the right steering knuckle 9 and the center line of the wheel end are extracted to determine the center point of the right kingpin (1.2). The bearing surfaces of the leaf spring seats on the left and right sides of the front beam 5 are found. This surface is a planar structure. The edge feature points of the four corners of the bearing surface are selected, and the geometric center of the bearing surface is obtained by using the planar center calculation function of the tool. The center of the left leaf spring seat is recorded as (2.1), and the center of the right side is recorded as (2.2). These four center points are integrated into the first subgroup of the second set of reference points.

[0053] S1023: Extend the kingpin axis to intersect with the upper and lower end faces of the front beam 5 end, and obtain four intersection points as the intersection points of the front beam end and the kingpin center line (8.1, 8.2, 9.1, 9.2), which are classified as subgroup two of the second group of reference points.

[0054] In some embodiments, with the left kingpin axis as a reference, the axis is extended towards the left end of the front beam 5 until it intersects with the upper end face of the left end of the front beam 5, and the intersection point is denoted as (8.1). The same axis is continued to be extended until it intersects with the lower end face of the left end of the front beam 5, denoted as (8.2).

[0055] Extend the right kingpin axis using the same procedure, so that it intersects with the upper end face of the right end of the front beam 5 to obtain (9.1), and with the lower end face to obtain (9.2). The four intersection points constitute the second subgroup of the second set of reference points, ensuring that each intersection point falls precisely in the intersection area of ​​the front beam end face and the kingpin axis.

[0056] In this embodiment, the intersection point is generated by the intersection of the kingpin axis and the front beam end face, which perfectly fits the structural assembly relationship of the front axle. There are no additional point deviations, so that the evaluation of longitudinal torsional stiffness can truly reflect the torsional performance of the front axle under braking conditions.

[0057] S103: Set constraint relationships, including: coupling constraint between the left and right wheel contact points (4.1, 4.2) and the steering knuckle (1, 9) axle head; hinge constraint between the front beam 5 and the steering knuckle (1, 9) mating end face; binding constraint between the steering tie rod arm (2, 8), steering knuckle arm 3 and steering knuckle (1, 9); ball joint connection between the steering tie rod arm (2, 8), tie rod assembly 7 and steering knuckle arm 3, and tie rod assembly 4; coupling the coordinate system center point 0 with the beam element and constraining the Y-axis displacement degree of freedom of the beam element 6 at the center of the left and right symmetry planes of the front axle; fixing the ball center point at the front end of the tie rod assembly 4; coupling the leaf spring seat center point (2.1, 2.2) with the leaf spring surface and constraining the X and Z axis displacement degrees of freedom and the rotational degree of freedom around the Y axis.

[0058] In some embodiments, coupling constraints ensure that the load is directly transmitted to the steering knuckle by forcing the wheel contact point to align with the displacement of the steering knuckle axle head. Articulation constraints release rotational degrees of freedom and restrict translational degrees of freedom, conforming to the actual rotational requirements of the steering knuckle relative to the front beam. Binding constraints form a rigid whole with the relevant components of the steering system, ensuring effective transmission of steering force. Ball joint connections simulate the angle adjustment function of the steering system by releasing multi-directional rotational degrees of freedom. The Y-axis displacement constraint of beam unit 6 simulates the lateral limitation of the front axle in the vehicle, the fixed ball center point at the front of the tie rod simulates the locking in straight-line mode, and the constraint of the leaf spring seat replicates the leaf spring's restriction on the longitudinal, vertical, and longitudinal torsional displacement of the front axle. All constraints together construct mechanical boundary conditions consistent with actual assembly.

[0059] S103 specifically includes the following steps: S1031: In the simulation model, the left wheel ground contact point (4.1) and the cylindrical contact surface of the left steering knuckle 1 axle head are set as coupling constraints, and the right wheel ground contact point (4.2) and the cylindrical contact surface of the right steering knuckle 9 axle head are set as coupling constraints; the front beam 5 and the annular mating end face of the left steering knuckle 1 and the right steering knuckle 9 are set as hinge constraints; the mounting flange surfaces of the left steering tie rod arm 2, the right steering tie rod arm 8, and the steering knuckle arm 3 are set as binding constraints with the corresponding mounting surfaces of the left steering knuckle 1 and the right steering knuckle 9; the ball joint seats of the left steering tie rod arm 2 and the right steering tie rod arm 8, and the ball joints at both ends of the tie rod assembly 7 are respectively set as ball joint connections with the ball joint holes of the steering knuckle arm 3 and the ball joint seats of the tie rod assembly 4.

[0060] In some embodiments, the left wheel grounding point (4.1) is located, which is a virtual contact point on the outer side of the left steering knuckle 1 axle head. The cylindrical outer surface of the left steering knuckle 1 axle head is selected as the constraint contact surface. The cylindrical contact surface and the left wheel grounding point (4.1) are bound together as a coupling constraint to ensure that the displacements of the two in the X, Y and Z directions are completely consistent, without relative sliding or separation.

[0061] Using the same method, the right wheel contact point (4.2) and the cylindrical outer surface of the right steering knuckle 9 axle head are set as coupling constraints. Then, the annular mating end faces of the front beam 5 and the steering knuckles (1, 9) are found. These end faces are precision-machined mating surfaces. The translational degrees of freedom of both are constrained in the X, Y, and Z directions, while only the rotational degrees of freedom around the central axis of the end face are retained to simulate the rotational relationship of the steering knuckle relative to the front beam in actual assembly.

[0062] In this embodiment, the mounting flange surfaces of the left steering tie rod arm 2 and the right steering tie rod arm 8, and the mounting plane of the steering knuckle arm 3 are selected. These two surfaces are aligned with the corresponding mounting planes on the steering knuckle, and a binding constraint is set to form a rigid connection between the three, with no relative displacement or deformation under force. The inner surfaces of the ball joint seats at the ends of the left steering tie rod arm 2 and the right steering tie rod arm 8, the outer surfaces of the ball heads at both ends of the tie rod assembly 7, the inner surfaces of the ball joint holes of the steering knuckle arm 3, and the inner surfaces of the ball joint seats of the tie rod assembly 4 are positioned, and the ball heads are paired with the ball joint holes to form a ball joint connection. This allows the ball heads to rotate around the X, Y, and Z coordinate axes within the ball joint holes, while restricting the translational degrees of freedom of both in the radial and axial directions, simulating the actual transmission relationship of the steering system.

[0063] S1032: In the simulation model, select beam element 6 at the center of the left and right symmetry planes of the front axle, establish a coupling relationship between the origin 0 of the coordinate system and the central section of beam element 6, and constrain the displacement degree of freedom of beam element 6 in the Y-axis direction; locate the center point of the ball at the front end of the steering tie rod assembly 4, set the center point as a fixed constraint, and restrict its displacement degree of freedom in the X, Y, and Z directions and rotational degree of freedom around the three coordinate axes.

[0064] In some embodiments, in the simulation model, beam element 6 is cut at the center position of the left and right symmetry planes of the front axle. Beam element 6 is a micro-segment solid of the front beam 5, and its central section coincides with the left and right symmetry planes of the front axle. The geometric center of the central section is selected, and a coupling constraint is established between it and the origin 0 of the coordinate system to ensure that the center of beam element 6 moves synchronously with the origin 0. The center point of the ball joint structure is found at the front end of the steering tie rod assembly 4. This point is the geometric center of the ball joint. Through the fixed constraint function of the software, the displacement degrees of freedom in the X, Y, and Z directions and the rotational degrees of freedom about the X, Y, and Z axes of this point are all constrained to keep its position fixed during the simulation, simulating the limitation of the steering control system on the straight-line state of the front axle.

[0065] S1033: In the simulation model, extract the center points (2.1, 2.2) of the leaf spring seat, and establish coupling constraints between the two center points and the leaf spring surface respectively. Constrain the displacement degrees of freedom of the center points (2.1, 2.2) of the leaf spring seat in the X-axis and Z-axis directions, and constrain their rotational degrees of freedom around the Y-axis.

[0066] In some embodiments, the leaf spring seat structures on the left and right sides of the front beam 5 are located in the simulation model, and the center points (2.1, 2.2) of the leaf spring seats are extracted. These points are the geometric center of the bearing surface of the leaf spring seats and coincide with the reference point established in S1022.

[0067] The center points of each leaf spring seat (2.1, 2.2) are associated with the leaf spring surface of the plane defined in S1013, ensuring that the motion trajectory of the center point always conforms to the leaf spring surface. Constraints are set for X-axis displacement, Z-axis displacement, and rotation around the Y-axis, retaining the rotational degrees of freedom around the X and Z axes and the displacement degrees of freedom around the Y axis. This simulates the mechanical characteristics of the leaf spring in actual operation, restricting the longitudinal (X-axis) and vertical (Z-axis) movement of the front axle and restricting the torsion around the longitudinal axis (Y-axis). The constraint settings reproduce the actual limiting effect of the leaf spring on the front axle, ensuring that the change in camber angle under impact conditions is only caused by the vertical bending of the front axle, and the bending and torsional deformation under braking conditions is only caused by the braking force. This allows the stiffness evaluation index to truly reflect the structural performance of the front axle itself, rather than abnormal deformation caused by insufficient external constraints.

[0068] S104: Based on the constraints of S103, a stepped load along the positive Z-axis is applied at the contact points of the left and right wheels (4.1, 4.2) to simulate the impact condition; the change in wheel camber angle Δα is calculated by the coordinate changes of the first set of reference points (both ends of rod element 10) before and after loading, and the change in camber angle Δα is used as the evaluation index of vertical stiffness.

[0069] S104 specifically includes the following steps: S1041: Define the load parameters for the impact condition, determine that the load application direction is the positive Z-axis direction, set the initial load value, maximum load value and load step size, and determine the stabilization time for each load step; In some embodiments, the direction of the impact load is determined to be along the positive Z-axis direction defined in S1013, taking into account the load range of the actual impact conditions on the front axle of the commercial vehicle. The initial load can simulate the initial state of the front axle without load; the maximum load is determined based on the maximum impact load when the commercial vehicle is fully loaded.

[0070] S1042: Based on the constraints and defined load parameters of S103, apply a stepped load along the positive Z-axis simultaneously at the contact points of the left and right wheels (4.1, 4.2) until the set maximum load value is reached; In some embodiments, in the load application module of the simulation software, the load type is set to "static load," and the loading direction is associated with the positive Z-axis direction defined in S1013. According to the parameters set in S1041, the load is gradually applied starting from the initial load value. After each load increment, loading is paused and waited until the load reaches the maximum value. During loading, the deformation state of the front axle is monitored in real time. If an abnormal change occurs in the deformation of the front axle at a certain load step, loading is paused, and the constraint settings in S103 are checked for correctness to ensure that the loading process is consistent with the actual impact force on the front axle.

[0071] S1043: Collect the initial coordinates of the first set of reference points (A0, B0) in S102 before loading, according to... Establish the relationship between the vertical stiffness of the front axle and the deformation around the X-axis under impact conditions, and determine the analysis process of deformation through the change of coordinates of the reference point; In some embodiments, before applying the load, the initial coordinates of the first set of reference points A0 (left end of rod element 10) and B0 (right end of rod element 10) established in S1021 are read and recorded as A0 (0, y0A, z0A) and B0 (0, y0B, z0B).

[0072] according to It can be seen that when the front axle is subjected to only vertical load under impact conditions, the deformation around the X-axis can intuitively reflect the vertical stiffness characteristics. The rod unit 10 is rigidly connected to the steering knuckle (1, 9), and the bending deformation of the steering knuckle around the X-axis will be synchronously transmitted to the rod unit 10, which will then manifest as the coordinate change of the reference points at both ends. Therefore, the analysis logic of quantifying the deformation around the X-axis and relating it to the vertical stiffness is established based on the coordinate change of the reference points.

[0073] The main correlation between the vertical stiffness of the front axle and the deformation around the X-axis under impact conditions was determined. The rigid connection between the rod element 10 and the steering knuckle allows the change of the reference point coordinates to directly map the deformation of the steering knuckle around the X-axis. Thus, the analysis link between the reference point data and the vertical stiffness is established through the correlation.

[0074] S1044: Substitute the acquired initial coordinates and the real-time coordinates of the reference points (An, Bn) after each load step stabilization into... Calculate the initial tilt angle α0° and the tilt angle αn° corresponding to each load step, and then obtain the tilt angle change Δα° = α n °-α0°; In some embodiments, the first set of reference points is rigidly connected to the rod unit 10, and the rod unit is coaxially assembled with the steering knuckle. The bending deformation of the steering knuckle is synchronously transmitted to the reference points, causing the coordinates to change. Based on the spatial coordinate relationship of the reference point, the coordinate changes are transformed into quantifiable outward tilt angles, combined with... The established correlation directly reflects the degree of deformation around the X-axis through the difference between the initial value and the value after loading, and thus maps the vertical stiffness.

[0075] This embodiment and The synergistic application of these technologies provides complete theoretical and data support for the calculation of the change in inclination angle, ensuring that the Δα values ​​under different load steps are comparable.

[0076] S1045: Establish the mapping relationship between the change in camber angle Δα and the corresponding load, determine Δα as the evaluation index of the front axle vertical stiffness, and form vertical stiffness characteristic data under impact conditions.

[0077] In some embodiments, the change in outward tilt angle Δα is achieved through... The correlation directly corresponds to the bending deformation of the front axle around the X-axis, which is a direct manifestation of the vertical stiffness. The mapping relationship between Δα and the load can present the stiffness characteristics of the front axle under different impact loads, and the resulting curve can intuitively reflect the trend of stiffness change with load.

[0078] S105: Based on the constraints of S103, the braking condition is simulated by simultaneously applying the support force along the positive Z-axis and the stepped braking force along the positive X-axis at the contact points of the left and right wheels (4.1, 4.2). The change in the bending deformation angle Δβ of the front axle around the Z-axis is calculated by changing the projection coordinates of the kingpin center point (1.1, 1.2) and the leaf spring seat center point (2.1, 2.2) in the XOY plane of the reference points in the second set of S102. Δβ is used as the evaluation index of longitudinal bending stiffness.

[0079] S105 specifically includes the following steps: S1051: Define the load parameters for braking conditions, set the vertical support force along the positive Z-axis to a constant value matching the full load state of the commercial vehicle, set the braking force along the positive X-axis to a stepped variation value, clarify the initial value, maximum value and load step size of the braking force, and determine the stable holding time of each load step. In some embodiments, the vertical support force corresponds to the vertical support of the wheel to the front axle when the commercial vehicle is braking, and the braking force corresponds to the horizontal braking force transmitted by the braking system. The combination of constant support force and stepped braking force fits the actual scenario where the vertical load is stable and the braking force gradually increases during the braking process. The stable holding time ensures that the deformation reaches a state of mechanical equilibrium.

[0080] S1052: Based on the constraints of S103 and the parameters defined in S1051, a constant vertical support force in the positive Z-axis direction is applied simultaneously at the contact points of the left and right wheels (4.1, 4.2), and then a stepped braking force in the positive X-axis direction is applied step by step according to the set step size until the maximum braking force value is reached. In some embodiments, the left and right wheel contact points simultaneously bear vertical support force and braking force. The constraint of S103 restricts the excess displacement of the front axle, ensuring that the vertical force maintains the front axle bearing load state. The braking force only causes the front axle to bend around the Z-axis, which is consistent with the actual force deformation under braking conditions.

[0081] S1053: Before loading, collect the initial projection coordinates of the kingpin center point (1.1, 1.2) and leaf spring seat center point (2.1, 2.2) in the XOY plane from the second set of reference points in S102, and substitute them into... Calculate the initial bending angle β0°; In some embodiments, before applying any load, the projection coordinates of the master pin center point (1.1) and leaf spring seat center point (2.1) established in S1022 in the XOY plane are read using the projection coordinate acquisition function of the simulation software and recorded as D0(x0D, y0D) and C0(x0C, y0C), respectively. The initial bending angle β0° was calculated.

[0082] Similarly, read the projected coordinates of the master pin center point (1.2) and the leaf spring seat center point (2.2) to verify the consistency of β0° and ensure the accuracy of the initial angle calculation.

[0083] S1054: After each braking load step stabilizes, acquire the real-time projected coordinates of the reference point in the XOY plane and substitute them into... Calculate the bending angle βn° under the corresponding load, and obtain the change in bending deformation angle by Δβ°=βn°-β0°; In some embodiments, after each braking force load step stabilizes, the real-time projected coordinates of the kingpin center point (1.1, 1.2) and the leaf spring seat center point (2.1, 2.2) in the XOY plane are collected. Taking the left reference point as an example, they are denoted as Dn(xnD, ynD) and Cn(xnC, ynC).

[0084] This embodiment substitutes these real-time projection coordinates... The bending angle βn° of the front axle around the Z-axis under the current braking force load is calculated. Combined with the initial bending angle β0° calculated by S1053, the change in bending deformation angle Δβ corresponding to this load step is obtained by using the formula Δβ°=βn°-β0°. After completing the calculation step by load step, a corresponding dataset of Δβ and braking force is formed.

[0085] S1055: Organize the braking force and Δβ value corresponding to each load step, establish the mapping relationship between the two, determine Δβ as the evaluation index of the longitudinal bending stiffness of the front axle, and form longitudinal bending stiffness characteristic data under braking conditions.

[0086] In some embodiments, the Δβ value obtained in S1054 and the corresponding braking force value are compiled into a data table. A Δβ braking force relationship curve is plotted with braking force as the abscissa and Δβ as the ordinate under braking conditions. Based on the positive correlation between the longitudinal bending deformation angle and the horizontal jump interference, Δβ is determined as the main indicator for evaluating the longitudinal bending stiffness of the front axle. Under the same braking force, the smaller the Δβ value, the smaller the bending deformation of the front axle around the Z-axis, and the better the longitudinal bending stiffness performance. This indicator is combined with the Δβ braking force curve to form complete evaluation data for the longitudinal bending stiffness of the front axle.

[0087] It can be seen that Δβ directly corresponds to the degree of bending deformation of the front axle around the Z-axis, and the deformation is a direct manifestation of the longitudinal bending stiffness. The mapping relationship between Δβ and braking force can fully present the longitudinal bending stiffness characteristics of the front axle under different braking intensities. The curve can intuitively reflect the trend of stiffness change with braking force.

[0088] S106: Based on the same braking condition in S105 and the constraints in S103, the change in the torsional deformation angle of the front axle around the Y-axis is calculated by changing the projection coordinates of the intersection points (8.1, 8.2, 9.1, 9.2) of the front beam ends in the second set of reference points in S102 in the XOZ plane. Δγ is used as the evaluation index of longitudinal torsional stiffness.

[0089] like Figure 5 The diagram shown is a visual representation of the torsional deformation of the front axle of a commercial vehicle under braking conditions, around the Y-axis of the spatial rectangular coordinate system defined in S101. It is used to visualize the core deformation pattern of the longitudinal torsional stiffness analysis of the front axle and directly corresponds to the torsional stiffness analysis steps in S106.

[0090] The diagram includes the front beam, steering knuckle, kingpin center point, and the intersection of the front beam end and the kingpin center line. The Y-axis of the spatial rectangular coordinate system is clearly marked to represent the axial reference for torsional deformation. The diagram uses double lines to illustrate the torsional trend of the front axle; the solid line represents the state before deformation, and the dashed line represents the deformation state after braking force is applied. During braking, the left and right wheel contact points simultaneously bear braking force along the positive X-axis. Under the constraints of the hinge between the front beam 5 and the steering knuckle, the X / Z axis displacement of the leaf spring seat center point, and the rotational constraint around the Y-axis, the front beam 5 undergoes torsion around the Y-axis.

[0091] Specifically, the upper and lower intersection points (8.1 and 8.2) of the left front beam end and the upper and lower intersection points (9.1 and 9.2) of the right front beam end exhibit significant relative displacement along the XOZ plane after deformation. The front beam 5 twists upward on one side and downward on the other side, forming a torsional posture around the Y-axis.

[0092] Figure 5This reflects the calculation basis for the change in torsional deformation angle Δγ in S106: Before deformation, the projected coordinates of the reference points in the XOZ plane correspond to the initial torsional deformation angle γ0°; after deformation, the projected coordinates of these reference points shift, and are substituted into... The torsional deformation angle γn° after loading can be calculated, and the torsional stiffness can be quantified by Δγ°=γn°-γ0°. The deformation pattern in the figure is consistent with the characteristic in the initial technical scheme that the greater the longitudinal torsional deformation, the less the horizontal interference, showing the correlation between the front axle torsional performance and the structural response under braking conditions.

[0093] S106 specifically includes the following steps: S1061: Lock the braking condition parameters of S105, and use its set constant value of vertical support force, braking force step parameters and load step stability holding time to determine the reference point to be the front beam end intersection point (8.1, 8.2, 9.1, 9.2) established by S1023. In some embodiments, the braking condition parameters of S105 are invoked to ensure that the load environment of the front bearing is consistent with the longitudinal bending stiffness analysis, thus eliminating the interference of operating condition differences on torsional deformation. The reference point is explicitly defined as the intersection of the front beam end and the kingpin axis. This type of point is directly related to the torsional displacement of the front beam and can capture torsional changes around the Y-axis.

[0094] S1062: Based on the constraints of S103 and the locked braking condition parameters, call the load application process of S105 to ensure the continuity and consistency of the braking condition. In some embodiments, the load application process in S105 is invoked to synchronize the application rhythm and stabilization time of the braking force with the longitudinal bending stiffness analysis, ensuring that the front axle undergoes torsional deformation under the same load sequence. The constraint in S103 restricts unnecessary displacement of the front axle, ensuring that the braking force only induces torsional deformation around the Y-axis, conforming to the actual torsional force logic under braking conditions. The invocation of the load process ensures the load consistency of the two longitudinal stiffness analyses, avoiding deformation deviations caused by differences in loading sequence.

[0095] S1063: Load the initial coordinates of the reference point's projection onto the XOZ plane, and substitute them into... Calculate the initial torsional deformation angle γ0°; In some embodiments, before applying any load, the initial projection coordinates of four reference points on the XOZ plane are read using the projection coordinate extraction function of the simulation software. Taking the left front beam as an example, the initial projection coordinates E0 (x0E, z0E) of the upper intersection point of the left front beam and the initial projection coordinates F0 (x0F, z0F) of the lower intersection point of the left front beam are recorded and substituted into... The initial torsional deformation angle γ0° was calculated; similarly, the initial projected coordinates of the two intersection points of the right front beam were read to verify the consistency of γ0° and ensure the accuracy of the initial torsional angle reference.

[0096] S1064: After each braking load step stabilizes, acquire the real-time projected coordinates of the reference point on the XOZ plane and substitute them into... Calculate the torsional deformation angle γ under the corresponding load. n °, the change in torsional deformation angle is obtained by Δγ°=γn°-γ0°; In some embodiments, after each braking load step stabilizes, the real-time projected coordinates of four reference points in the XOZ plane are acquired. Taking the left front beam reference point as an example, these are denoted as En(xnE, znE) and Fn(xnF, znF). These real-time projected coordinates are then substituted into... The torsional deformation angle γ of the front axle around the Y-axis under the current braking force load is calculated. n °. Combining the initial torsional deformation angle γ0° calculated by S1063, the change in torsional deformation angle Δγ corresponding to this load step is obtained by using the formula Δγ°=γn°-γ0°. After completing the calculation step by step, a one-to-one correspondence dataset of Δγ and braking force is formed.

[0097] In this embodiment, under braking load, the torsional deformation of the front axle around the Y-axis will cause the intersection point of the front beam end to shift synchronously, causing its projection coordinates in the XOZ plane to shift. Based on the offset coordinate data, the torsional deformation angle γ after loading is quantized. n °, improves the data reliability of longitudinal torsional stiffness analysis.

[0098] S1065: Organize the braking force and Δγ value corresponding to each load step, establish the mapping relationship between the two, determine Δγ as the evaluation index of the longitudinal torsional stiffness of the front axle, and form longitudinal torsional stiffness characteristic data under braking conditions.

[0099] In some embodiments, the Δγ value obtained in S1064 and the corresponding braking force value are organized into a standardized data table, and the Δγ-braking force relationship curve under braking conditions is plotted with braking force as the abscissa and Δγ as the ordinate.

[0100] Based on the negative correlation between the longitudinal torsional deformation angle and the horizontal interference, Δγ is clearly identified as the main indicator for evaluating the longitudinal torsional stiffness of the front axle. Under the same braking force, a larger Δγ value indicates a greater torsional deformation of the front axle around the Y-axis, and better longitudinal torsional stiffness performance. This indicator is combined with the Δγ-braking force curve to form complete evaluation data for the longitudinal torsional stiffness of the front axle, complementing the longitudinal bending stiffness data of S105. This data can be used to independently determine the longitudinal torsional stiffness level of the front axle, and can also be combined with the Δβ data of S105 to comprehensively evaluate the longitudinal stiffness characteristics of the front axle.

[0101] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0102] The following are embodiments of the commercial vehicle front axle stiffness analysis and evaluation system provided in this disclosure. This system and the commercial vehicle front axle stiffness analysis and evaluation methods in the above embodiments belong to the same inventive concept. For details not described in detail in the embodiments of the commercial vehicle front axle stiffness analysis and evaluation system, please refer to the embodiments of the above commercial vehicle front axle stiffness analysis and evaluation methods.

[0103] The system includes: The model construction definition module is used to construct a three-dimensional solid assembly model of the front axle of a commercial vehicle, and to assemble rod units at the ends of the steering knuckles on both sides of the front axle; the position of the front axle is defined in a spatial rectangular coordinate system, with the origin 0 being the intersection of the front axle's front-rear symmetry plane, left-right symmetry plane, and leaf spring surface; the X-axis points in the opposite direction of vehicle travel, the Y-axis points to the right side of the vehicle, and the Z-axis is vertically upward; The reference point establishment module is used to establish reference points on the model, including: establishing a first set of reference points at both ends of the rod unit; and establishing a second set of reference points at the center point of the front axle kingpin, the center point of the leaf spring seat, and the intersection of the end of the front beam and the center line of the kingpin. The constraint setting module is used to set constraint relationships, including: coupling constraints between the left and right wheel contact points and the steering knuckle axle head; hinge constraints between the front beam and the steering knuckle mating end face; binding constraints between the steering tie rod arm, steering knuckle arm, and steering knuckle; ball joint connections between the steering tie rod arm, tie rod assembly, steering knuckle arm, and tie rod assembly; coupling the coordinate system center point 0 with the beam element and constraining the Y-axis displacement degree of freedom of the beam element at the center of the left and right symmetry planes of the front axle; fixing the center point of the front ball of the tie rod assembly; coupling the leaf spring seat center point with the leaf spring surface and constraining the X and Z axis displacement degrees of freedom and the rotational degree of freedom around the Y-axis; The vertical stiffness analysis module, based on the S103 constraint, applies a stepped load along the positive Z-axis at the contact points of the left and right wheels to simulate impact conditions; it calculates the change in wheel camber angle Δα by changing the coordinates of the first set of reference points before and after loading, and uses the change in camber angle Δα as the evaluation index of vertical stiffness. The longitudinal bending stiffness analysis module, based on the S103 constraint, simultaneously applies a support force along the positive Z-axis and a stepped braking force along the positive X-axis at the contact points of the left and right wheels to simulate braking conditions. By changing the projection coordinates of the kingpin center point and the leaf spring seat center point in the second set of reference points on the XOY plane, the change in the bending deformation angle Δβ of the front axle around the Z-axis is calculated, and Δβ is used as the evaluation index of longitudinal bending stiffness. The longitudinal torsional stiffness analysis module, based on the same braking condition S105 and the constraint S103, calculates the change in the torsional deformation angle Δγ of the front axle around the Y-axis by changing the projection coordinates of the intersection point of the front beam end in the XOZ plane in the second set of reference points, and uses Δγ as the evaluation index of longitudinal torsional stiffness.

[0104] like Figure 7 As shown, this application also provides an electronic device, including a display module 103, a memory 102, a processor 101, a communication module 104, and a computer program stored in the memory and executable on the processor 101. When the processor 101 executes the program, it implements the steps of a method for analyzing and evaluating the front axle stiffness of commercial vehicles.

[0105] In embodiments of the present invention, electronic devices include, but are not limited to, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the embodiments described and / or claimed herein.

[0106] In this embodiment, processor 101 may be implemented using at least one of an application-specific integrated circuit, a programmable logic device, a field-programmable gate array, a processor, a controller, a microcontroller, a microprocessor, or an electronic unit designed to perform the functions described herein. In some cases, such an implementation may be implemented within a controller. For software implementation, implementations such as processes or functions may be implemented with separate software modules that allow the performance of at least one function or operation. Software code may be implemented by a software application (or program) written in any suitable programming language, and the software code may be stored in memory and executed by the controller.

[0107] The display module 103 is used to display information input by the user or information provided to the user. The display module 103 may include a display panel, which may be configured in the form of a liquid crystal display, an organic light-emitting diode, or the like.

[0108] The memory 102 can be used to store software programs and various data. The memory 102 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0109] The communication module 104 transmits radio signals to and / or receives radio signals from at least one of a base station, an external terminal, and a server. Such radio signals may include voice call signals, video call signals, or various types of data sent and / or received according to text and / or multimedia messages.

[0110] The present invention also provides a storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the commercial vehicle front axle stiffness analysis and evaluation method.

[0111] The storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example,, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0112] The storage medium stores a program product capable of implementing the methods described above in this specification. In some possible implementations, various aspects of this disclosure may also be implemented as a program product comprising program code that, when run on a terminal device, causes the terminal device to perform the steps described in the "Exemplary Methods" section of this specification according to various exemplary embodiments of this disclosure.

[0113] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for analyzing and evaluating the front axle stiffness of commercial vehicles, characterized in that the method... include: S101: Construct a three-dimensional solid assembly model of the front axle of a commercial vehicle, and assemble rod units at the ends of the steering knuckles on both sides of the front axle; define the position of the front axle in a spatial rectangular coordinate system, with the origin 0 of the coordinate system being the intersection of the front-rear symmetry plane, the left-right symmetry plane and the leaf spring surface of the front axle, the X-axis pointing in the opposite direction of vehicle travel, the Y-axis pointing to the right side of the vehicle, and the Z-axis pointing vertically upward; S102: Establish reference points on the model, including: establishing a first set of reference points at both ends of the rod unit; and establishing a second set of reference points at the center point of the front axle kingpin, the center point of the leaf spring seat, and the intersection of the end of the front beam and the center line of the kingpin. S103: Set constraint relationships, including: coupling constraints between the left and right wheel contact points and the steering knuckle axle head; hinge constraints between the front beam and the steering knuckle mating end face; binding constraints between the steering tie rod arm, steering knuckle arm and steering knuckle; ball joint connection between the steering tie rod arm, tie rod assembly and steering knuckle arm, and tie rod assembly; coupling the coordinate system center point 0 with the beam element and constraining the Y-axis displacement degree of freedom of the beam element at the center of the left and right symmetry planes of the front axle; fixing the ball center point at the front end of the tie rod assembly; coupling the leaf spring seat center point with the leaf spring surface and constraining the X and Z axis displacement degrees of freedom and the rotational degree of freedom around the Y-axis; S104: Based on the constraint of S103, a stepped load along the positive Z-axis is applied to the contact points of the left and right wheels to simulate the impact condition; the change in wheel camber angle Δα is calculated by the coordinate change before and after loading of the first set of reference points, and the change in camber angle Δα is used as the vertical stiffness evaluation index. S105: Based on the constraint of S103, the braking condition is simulated by simultaneously applying the support force along the positive Z-axis and the stepped braking force along the positive X-axis at the contact points of the left and right wheels; by changing the projection coordinates of the kingpin center point and the leaf spring seat center point in the second set of reference points on the XOY plane, the change in the bending deformation angle Δβ of the front axle around the Z-axis is calculated, and Δβ is used as the evaluation index of longitudinal bending stiffness. S106: Based on the same braking condition in S105 and the constraints in S103, the change in the torsional deformation angle Δγ of the front axle around the Y-axis is calculated by changing the projection coordinates of the intersection point of the front beam ends in the XOZ plane in the second set of reference points. Δγ is used as the evaluation index of longitudinal torsional stiffness.

2. The method for analyzing and evaluating the front axle stiffness of commercial vehicles according to claim 1, characterized in that, S101 specifically includes the following steps: S1011: Obtain the three-dimensional data of the left steering knuckle (1), right steering knuckle (9), left steering tie rod arm (2), right steering tie rod arm (8), steering knuckle arm (3), steering tie rod assembly (4), front beam (5), and tie rod assembly (7) of the front axle of the commercial vehicle. Construct three-dimensional solid models of each component based on the three-dimensional data, and then assemble them in sequence according to the actual assembly and connection relationship of each component to form the initial solid assembly model of the front axle. S1012: In the initial solid assembly model of the front axle, cylindrical assembly surfaces are selected at the ends of the left steering knuckle (1) and the right steering knuckle (9), and the two ends of the rod unit (10) are coaxially assembled with the cylindrical assembly surfaces of the steering knuckle ends; the wheel end structure part in the model is removed to obtain the simplified solid assembly model of the front axle. S1013: In the front axle solid assembly model, determine the front and rear symmetry planes, left and right symmetry planes, and leaf spring surface of the front axle. Take the intersection point of these three planes as the origin 0 of the spatial rectangular coordinate system. Set the direction pointing in the opposite direction of vehicle travel as the positive X-axis, the direction facing the right side of the vehicle in the direction of travel as the positive Y-axis, and the vertical upward direction as the positive Z-axis, thus completing the position definition of the front axle in this coordinate system.

3. The method for analyzing and evaluating the front axle stiffness of commercial vehicles according to claim 1, characterized in that, S102 specifically includes the following steps: S1021: Locate the center position on the circular end face at both ends of the rod element (10), and generate two reference points at the center using a 3D modeling tool to form the first set of reference points, denoted as A0 and B0; S1022: Extract the axis of the front axle kingpin and the axis of the steering knuckle axle head, and determine the intersection of the two axes as the kingpin center point. Extract the geometric center of the leaf spring seat bearing surface as the leaf spring seat center point, and classify the center point as subgroup one of the second set of reference points. S1023: Extend the main pin axis to intersect with the upper and lower end faces of the front beam (5) and obtain four intersection points as the intersection points of the front beam end and the main pin center line, which are classified as subgroup two of the second group of reference points.

4. The method for analyzing and evaluating the front axle stiffness of commercial vehicles according to claim 1, characterized in that, S103 specifically includes the following steps: S1031: In the simulation model, the cylindrical contact surface between the left wheel grounding point and the left steering knuckle (1) axle head is set as a coupling constraint, and the cylindrical contact surface between the right wheel grounding point and the right steering knuckle (9) axle head is set as a coupling constraint; the annular mating end face between the front beam (5) and the left steering knuckle (1) and the right steering knuckle (9) is set as a hinge constraint; the mounting flange surfaces of the left steering tie rod arm (2), the right steering tie rod arm (8), and the steering knuckle arm (3) are set as binding constraints with the corresponding mounting surfaces of the left steering knuckle (1) and the right steering knuckle (9); the ball joint seats of the left steering tie rod arm (2) and the right steering tie rod arm (8), the ball joints at both ends of the tie rod assembly (7) are respectively set as ball joint connections with the ball joint holes of the steering knuckle arm (3) and the ball joint seats of the tie rod assembly (4); S1032: In the simulation model, select the beam element (6) at the center of the left and right symmetry planes of the front axle, establish a coupling relationship between the origin 0 of the coordinate system and the center section of the beam element (6), and constrain the displacement degree of freedom of the beam element (6) in the Y-axis direction; locate the center point of the ball at the front end of the steering tie rod assembly (4), set the center point as a fixed constraint, and restrict its displacement degree of freedom in the X, Y, and Z directions and its rotational degree of freedom around the three coordinate axes; S1033: In the simulation model, extract the center point of the leaf spring seat, establish coupling constraints between the two center points and the leaf spring surface respectively, constrain the displacement degree of freedom of the center point of the leaf spring seat in the X-axis and Z-axis directions, and constrain its rotational degree of freedom around the Y-axis.

5. The method for analyzing and evaluating the front axle stiffness of commercial vehicles according to claim 1, characterized in that, S104 specifically includes the following steps: S1041: Define the load parameters for the impact condition, determine that the load application direction is the positive Z-axis direction, set the initial load value, maximum load value and load step size, and determine the stabilization time for each load step; S1042: Based on the constraints and defined load parameters of S103, apply a stepped load along the positive Z-axis simultaneously at the contact points of the left and right wheels until the set maximum load value is reached. S1043: Acquire the initial coordinates of the first set of reference points in S102 before loading, according to Establish the relationship between the vertical stiffness of the front axle and the deformation around the X-axis under impact conditions, and determine the analysis process of deformation through the change of coordinates of the reference point; S1044: Substitute the acquired initial coordinates and the real-time coordinates of the reference point after each load step stabilization into... Calculate the initial tilt angle α0° and the tilt angle α corresponding to each load step. n °, thus obtaining the change in outward tilt angle Δα°=α n °-α0°; S1045: Establish the mapping relationship between the change in camber angle Δα and the corresponding load, determine Δα as the evaluation index of the front axle vertical stiffness, and form vertical stiffness characteristic data under impact conditions.

6. The method for analyzing and evaluating the front axle stiffness of commercial vehicles according to claim 1, characterized in that, S105 specifically includes the following steps: S1051: Define the load parameters for braking conditions, set the vertical support force along the positive Z-axis to a constant value matching the full load state of the commercial vehicle, set the braking force along the positive X-axis to a stepped variation value, clarify the initial value, maximum value and load step size of the braking force, and determine the stable holding time of each load step. S1052: Based on the constraints of S103 and the parameters defined in S1051, a constant vertical support force in the positive Z-axis direction is applied synchronously at the contact points of the left and right wheels, and then a stepped braking force in the positive X-axis direction is applied step by step according to the set step size until the maximum braking force value is reached. S1053: Collect the initial projection coordinates of the kingpin center point and leaf spring seat center point in the second set of reference points in S102 onto the XOY plane before loading, and substitute them into... Calculate the initial bending angle β0°; S1054: After each braking load step stabilizes, acquire the real-time projected coordinates of the reference point in the XOY plane and substitute them into... Calculate the bending angle βn° under the corresponding load, and obtain the change in bending deformation angle by Δβ°=βn°-β0°; S1055: Organize the braking force and Δβ value corresponding to each load step, establish the mapping relationship between the two, determine Δβ as the evaluation index of the longitudinal bending stiffness of the front axle, and form longitudinal bending stiffness characteristic data under braking conditions.

7. The method for analyzing and evaluating the front axle stiffness of commercial vehicles according to claim 1, characterized in that, S106 specifically includes the following steps: S1061: Lock the braking condition parameters of S105, and use its set constant value of vertical support force, braking force step parameters and load step stability holding time to determine the reference point for acquisition as the established front beam end intersection point. S1062: Based on the constraints of S103 and the locked braking condition parameters, the load application process of S105 is called synchronously to ensure the continuity and consistency of the braking condition. S1063: Load the initial coordinates of the reference point's projection onto the XOZ plane, and substitute them into... Calculate the initial torsional deformation angle γ0°; S1064: After each braking load step stabilizes, acquire the real-time projected coordinates of the reference point on the XOZ plane and substitute them into... Calculate the torsional deformation angle γ under the corresponding load. n °, the change in torsional deformation angle is obtained by Δγ°=γn°-γ0°; S1065: Organize the braking force and Δγ value corresponding to each load step, establish the mapping relationship between the two, determine Δγ as the evaluation index of the longitudinal torsional stiffness of the front axle, and form longitudinal torsional stiffness characteristic data under braking conditions.

8. A system for analyzing and evaluating the front axle stiffness of commercial vehicles, characterized in that, The system is used to implement the method for analyzing and evaluating the front axle stiffness of commercial vehicles as described in any one of claims 1 to 7; The system includes: The model construction definition module is used to construct a three-dimensional solid assembly model of the front axle of a commercial vehicle, and to assemble rod units at the ends of the steering knuckles on both sides of the front axle; the position of the front axle is defined in a spatial rectangular coordinate system, with the origin 0 being the intersection of the front axle's front-rear symmetry plane, left-right symmetry plane, and leaf spring surface; the X-axis points in the opposite direction of vehicle travel, the Y-axis points to the right side of the vehicle, and the Z-axis is vertically upward; The reference point establishment module is used to establish reference points on the model, including: establishing a first set of reference points at both ends of the rod unit; and establishing a second set of reference points at the center point of the front axle kingpin, the center point of the leaf spring seat, and the intersection of the end of the front beam and the center line of the kingpin. The constraint setting module is used to set constraint relationships, including: coupling constraints between the left and right wheel contact points and the steering knuckle axle head; hinge constraints between the front beam and the steering knuckle mating end face; binding constraints between the steering tie rod arm, steering knuckle arm, and steering knuckle; ball joint connections between the steering tie rod arm, tie rod assembly, steering knuckle arm, and tie rod assembly; coupling the coordinate system center point 0 with the beam element and constraining the Y-axis displacement degree of freedom of the beam element at the center of the left and right symmetry planes of the front axle; fixing the center point of the front ball of the tie rod assembly; coupling the leaf spring seat center point with the leaf spring surface and constraining the X and Z axis displacement degrees of freedom and the rotational degree of freedom around the Y-axis; The vertical stiffness analysis module, based on the S103 constraint, applies a stepped load along the positive Z-axis at the contact points of the left and right wheels to simulate impact conditions; it calculates the change in wheel camber angle Δα by changing the coordinates of the first set of reference points before and after loading, and uses the change in camber angle Δα as the evaluation index of vertical stiffness. The longitudinal bending stiffness analysis module, based on the S103 constraint, simultaneously applies a support force along the positive Z-axis and a stepped braking force along the positive X-axis at the contact points of the left and right wheels to simulate braking conditions. By changing the projection coordinates of the kingpin center point and the leaf spring seat center point in the second set of reference points on the XOY plane, the change in the bending deformation angle Δβ of the front axle around the Z-axis is calculated, and Δβ is used as the evaluation index of longitudinal bending stiffness. The longitudinal torsional stiffness analysis module, based on the same braking condition S105 and the constraint S103, calculates the change in the torsional deformation angle Δγ of the front axle around the Y-axis by changing the projection coordinates of the intersection point of the front beam end in the XOZ plane in the second set of reference points, and uses Δγ as the evaluation index of longitudinal torsional stiffness.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the commercial vehicle front axle stiffness analysis and evaluation method as described in any one of claims 1 to 7.

10. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the commercial vehicle front axle stiffness analysis and evaluation method as described in any one of claims 1 to 7.

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