Shock absorber road load acquisition method, analysis method and system, and storage medium

Abstract

The application relates to a shock absorber road load acquisition method, an analysis method and system and a storage medium, which comprise the following steps: determining hard points connected with other components in a shock absorber assembly in a suspension design state; establishing a shock absorber assembly dynamics model, and establishing a local load coordinate system of each hard point related to the dynamic load of a shock absorber piston rod on the shock absorber piston rod; establishing a local load coordinate system of each hard point related to the dynamic load of a shock absorber cylinder on the shock absorber cylinder; setting displacement output between an upper point of the shock absorber piston rod and a lower fixed center point of the shock absorber, force and torque output borne by the shock absorber piston rod, and force and torque output borne by the shock absorber cylinder; establishing a whole vehicle multi-body dynamics model; and simulating the response of each system of the vehicle under various virtual road surface excitations. The application can truly simulate the change condition of the shock absorber road load.

Description

Technical Field

[0001] This invention belongs to the field of automotive CAE simulation technology, specifically relating to a method, analysis method, system, and storage medium for obtaining road loads on shock absorbers. Background Technology

[0002] Shock absorbers are one of the key components of automotive suspension systems, responsible for guiding the mechanism, absorbing energy, and filtering vibrations. During actual driving, shock absorbers are subjected to complex alternating loads due to changes in road surface and vehicle speed. Given their complex structure and integration of multiple disciplines and key performance components, conducting simulation analysis in the early stages of R&D to mitigate risks is a pressing challenge for OEMs and suppliers.

[0003] Currently, it is impossible to accurately obtain the road load of the shock absorber, which is reflected in: (1) There are many types of vehicle suspension, such as MacPherson, double wishbone, multi-link, torsion beam, etc. The arrangement and installation position of the shock absorber are different, and there is a lack of a unified method for obtaining the road load of the shock absorber cylinder and the shock absorber piston rod; (2) The traditional load decomposition of the shock absorber cylinder and the shock absorber piston rod only relies on empirical formulas and fails to consider the complex alternating load transmission during the movement of the shock absorber.

[0004] Currently, no literature on obtaining road loads for the shock absorber piston rod and shock absorber cylinder has been found. Only literature on conducting strength and durability analysis of the shock absorber fork under empirical loads on a test bench system has been found. For example, patent document CN115292797A discloses a method to improve the simulation accuracy of strength and durability of the double wishbone suspension shock absorber fork. This method proposes to apply vertical force load and forced displacement at the wheel center of the double wishbone suspension system. However, this method is limited to static loading on the suspension test bench and ignores the dynamic excitation input of longitudinal, lateral, and vertical forces and three-directional moments at the wheel center during vehicle operation. Furthermore, it cannot guarantee the equivalence between the test bench load and the road load.

[0005] Due to the lack of effective methods in dynamic software for modeling and load processing of shock absorbers, the road loads on the shock absorber piston rod and shock absorber cylinder cannot be accurately decomposed and obtained. The literature "Modeling and Application of Flexible Shock Absorbers for MacPherson Suspension Performance Development" (Article No.: 1000-3703(2016)02-0011-04) mentions that a virtual bushing method is used to construct a flexible shock absorber model, and a step function is used to describe the contact force between the shock absorber piston rod and the shock absorber cylinder, which improves the prediction accuracy of MacPherson suspension and vehicle performance. However, the step coefficient will affect the calculation accuracy of lateral force, and the excessive model complexity will lead to low simulation efficiency and difficulty in engineering implementation. In addition, the load transfer path between the shock absorber cylinder and the shock absorber piston rod is complex. The traditional constraint method of cylindrical pair between the shock absorber piston rod and the shock absorber cylinder cannot obtain the radial force of the shock absorber piston rod change and the shock absorber guide position during vehicle driving, and cannot meet the purpose of shock absorber lateral force decomposition.

[0006] Therefore, it is necessary to develop a new method, analysis method, system, and storage medium for obtaining road loads on vibration dampers. Summary of the Invention

[0007] The purpose of this invention is to provide a method, analysis method, system, and storage medium for obtaining road loads on shock absorbers, which can realistically simulate the changes in road loads on shock absorbers.

[0008] In a first aspect, the method for obtaining the road load of the shock absorber according to the present invention includes the following steps:

[0009] Identify the hard points where the shock absorber assembly connects to other components in the suspension design state;

[0010] A dynamic model of the shock absorber assembly is established, specifically as follows: based on the actual physical model and motion relationship of the shock absorber assembly, point-line pair constraints are established between the shock absorber piston rod and the shock absorber cylinder at the center point D of the shock absorber guide and the center point F of the shock absorber piston, respectively. The direction of the straight line is the direction of the line connecting the upper point A of the shock absorber piston rod and the lower fixed center point I of the shock absorber cylinder. The damping of the shock absorber assembly is simulated by the damping force element acting between the shock absorber piston rod and the shock absorber cylinder.

[0011] In the dynamic model of the shock absorber assembly, establish a local load coordinate system on the piston rod of the shock absorber that is related to the dynamic load of the piston rod.

[0012] In the dynamic model of the shock absorber assembly, establish a local load coordinate system on the shock absorber cylinder that is related to the dynamic load of the shock absorber cylinder;

[0013] In the dynamic model of the shock absorber assembly, the displacement output between the upper point A of the shock absorber piston rod and the lower fixed center point I of the shock absorber cylinder is set. In the established load coordinate system, the force and torque output of the shock absorber piston rod and the force and torque output of the shock absorber cylinder are set.

[0014] Establish a multibody dynamics model for the entire vehicle;

[0015] The vehicle multibody dynamics model is connected to the shock absorber assembly dynamics model via communication to simulate the response of various vehicle systems under various virtual road surface excitations, and output data related to road loads on the shock absorber assembly, including the displacement between the upper point A of the shock absorber piston rod and the lower fixed center point I of the shock absorber cylinder, the force and torque on the shock absorber piston rod, and the force and torque on the shock absorber cylinder.

[0016] Optionally, the hard points connecting the shock absorber assembly to other components in the suspension design state include: point A on the upper part of the shock absorber piston rod, point C on the center of the upper end face of the shock absorber cylinder, point D on the center of the shock absorber guide, point E on the center of the internal limiting pad of the shock absorber, point F on the center of the shock absorber piston, and point I on the lower fixed center of the shock absorber cylinder. These six points are essential in commonly used automotive suspension structures.

[0017] Optionally, the hard points connecting the shock absorber assembly to other components in the suspension design state also include: the center point B of the spring seat, point G on the stabilizer bar connecting bracket, and the center point J of the shock absorber bracket. Depending on the different suspension structure, the connection points to the shock absorber assembly may also include these three optional points. Adding these three points can better accommodate different suspension structure types.

[0018] Optionally, a local load coordinate system is established on the piston rod of the damper assembly in the dynamic model of the damper assembly, relating to the dynamic load of the piston rod and each hard point therein. Specifically:

[0019] Identify the hard points related to the dynamic load of the damper piston rod, including the upper point A of the damper piston rod, the center point D of the damper guide, the center point E of the internal limiting pad of the damper, and the center point F of the damper piston.

[0020] Local load coordinates are established for each hard point. Specifically, with the hard point as the origin, the vector formed by the lower fixed center point I of the shock absorber cylinder and the upper point A of the shock absorber piston rod is the Z-direction. The projection of the vehicle coordinate X-axis onto the Z-direction normal plane of the corresponding local load coordinate system is the X-direction, and the Y-direction is determined by the right-hand rule. This invention establishes the local load coordinate system in this way to obtain the dynamic load of the shock absorber piston rod and to characterize the accurate dynamic position and direction of the shock absorber piston rod under vehicle motion.

[0021] Optionally, a local load coordinate system related to the dynamic load of each hard point on the damper cylinder in the dynamic model of the damper assembly is established, specifically as follows:

[0022] Determine the hard points related to the dynamic load of the damper cylinder, including the center point B of the spring seat, the center point C of the upper end face of the damper cylinder, the center point D of the damper guide, the center point F of the damper piston, the point G on the stabilizer bar connecting bracket, the center point H of the bottom valve 9 of the damper cylinder, and the lower fixed center point I of the damper cylinder 2.

[0023] Local load coordinates are established for each hard point. Specifically, with the hard point as the origin, the vector formed by the lower fixed center point I of the shock absorber cylinder 2 and the upper point A of the shock absorber piston rod is the Z-direction. The projection of the vehicle coordinate X-axis onto the Z-direction normal plane of the corresponding local load coordinate system is the X-direction, and the Y-direction is determined by the right-hand rule. The purpose of establishing the local load coordinate system in this way is to obtain the dynamic load of the shock absorber cylinder unit (including the shock absorber connecting bracket) and to establish a load coordinate system on the shock absorber cylinder to characterize the accurate dynamic position and direction of the shock absorber cylinder under the motion of the vehicle.

[0024] Optionally, the vehicle multibody dynamics model integrates the suspension, body, powertrain, braking system, steering system, and tire system.

[0025] Secondly, the road load analysis method for a vibration damper according to the present invention includes the following steps:

[0026] Data related to the road load of the shock absorber assembly obtained using the road load acquisition method for the shock absorber as described in this invention;

[0027] The dynamic load of the time-varying region of the shock absorber piston rod and shock absorber cylinder is processed as follows: the time-varying region of the shock absorber piston rod and shock absorber cylinder is discretized, and the force region of the moving point is determined in real time according to the shock absorber's motion stroke. The continuous road load spectrum is multiplied by a preset square wave function to obtain the force conditions of each moving point in the motion region of the shock absorber piston rod and each moving point in the motion region of the shock absorber cylinder.

[0028] Optionally, the dynamic load handling for the time-varying region of the shock absorber piston rod is specifically as follows:

[0029] Discretize the force-bearing area of ​​the shock absorber piston rod and count the stroke of the shock absorber piston rod for each road surface.

[0030] The region formed by the movement of the shock absorber piston rod relative to the shock absorber guide during the vehicle's motion is taken as a discrete object;

[0031] Taking the upper center point of the shock absorber piston rod movement area in the vehicle's ready state as the origin, along the axis of the shock absorber piston rod, the area is uniformly divided into N1 equal discrete regions with a thickness T1.

[0032] Record and output the coordinates of the center point of each discrete region;

[0033] The force exerted by the damper cylinder at the center point D of the output damper guide on the damper piston rod is distributed to N1 discrete regions, resulting in the force exerted by the damper cylinder at the center point D of the damper guide in N1 discrete regions.

[0034] The load spectra of each fixed point on the shock absorber piston rod, excluding the center point D of the shock absorber guide, are combined with the road loads at the center points of N1 discrete regions to output the road load file of the shock absorber piston rod. Two point-line pairs are used to constrain the relative motion between the shock absorber cylinder and the shock absorber piston rod. Combined with time-varying regional dynamic load processing, the implementation method is simple and can completely obtain the dynamic load of the shock absorber piston rod under its motion state.

[0035] Optionally, the dynamic load treatment for the time-varying region of the damper cylinder is as follows:

[0036] Discretize the stress area of ​​the shock absorber cylinder and count the piston rod stroke of each road surface shock absorber.

[0037] The region formed by the movement of the shock absorber cylinder relative to the shock absorber piston during the movement of the whole vehicle is regarded as a discrete object;

[0038] Taking the center point of the shock absorber cylinder's motion area in the vehicle's ready state as the origin, along the axis of the shock absorber cylinder, the area is evenly divided into N2 equal parts with a thickness of T2.

[0039] Record and output the coordinates of the center point of each discrete region;

[0040] The force exerted by the piston rod at the center point F of the output damper piston on the damper cylinder is distributed to N2 discrete regions, resulting in the force exerted by the piston at the center point F of the damper piston on the damper cylinder in N2 discrete regions.

[0041] The load spectra of each fixed point on the shock absorber cylinder, excluding the center point F of the shock absorber piston, are combined with the road loads of N2 discrete regions to output the road load file of the shock absorber cylinder. Two point-line pairs are used to constrain the relative motion between the shock absorber cylinder and the shock absorber piston rod. Combined with time-varying regional dynamic load processing, the implementation method is simple and can completely obtain the dynamic load of the shock absorber cylinder under motion conditions.

[0042] Thirdly, the road load acquisition system for a shock absorber according to the present invention includes a memory and a controller. The memory stores a computer-readable program, which, when invoked by the controller, can execute the steps of the road load acquisition method for the shock absorber as described in the present invention.

[0043] Fourthly, the road load analysis system for a shock absorber according to the present invention includes a memory and a controller. The memory stores a computer-readable program, which, when invoked by the controller, can execute the steps of the road load analysis method for the shock absorber as described in the present invention.

[0044] Fifthly, the present invention provides a storage medium storing a computer-readable program that, when invoked, can execute the steps of the road load acquisition method for the shock absorber as described in the present invention.

[0045] Sixthly, the present invention provides a storage medium storing a computer-readable program that, when invoked, can execute the steps of the road load analysis method for the shock absorber as described in the present invention.

[0046] The present invention has the following advantages:

[0047] (1) Based on the actual physical model and motion relationship of the shock absorber assembly, this invention establishes point-line pairs at two locations: the shock absorber guide and the shock absorber piston. These pairs constrain the shock absorber piston rod and the shock absorber cylinder, with the straight line direction being the line connecting the upper point A of the shock absorber piston rod and the lower fixed center point I of the shock absorber cylinder. This radial constraint on the shock absorber piston rod and the shock absorber cylinder ensures the degree of freedom of the shock absorber piston rod and the shock absorber cylinder along the axial direction. The point-line pair modeling of the shock absorber has the same constrained degree of freedom as the traditional cylindrical pair modeling, solving the problem that the traditional cylindrical pair modeling method for shock absorbers cannot extract lateral forces.

[0048] (2) This invention proposes a method for obtaining and analyzing road loads of shock absorbers, which fills the gap in load technology for road fatigue analysis of shock absorbers and realizes the fatigue performance analysis, optimization and control of shock absorber piston rod and shock absorber cylinder in the early stage of research and development.

[0049] (3) By sorting out different suspension types, including MacPherson strut, double wishbone, multi-link and torsion beam, this invention establishes a model template, and by solidifying the connection method of the shock absorber piston rod and the shock absorber cylinder and the load output request, it avoids repeated modeling and modification, and improves the versatility of the method.

[0050] (4) Based on the virtual test field technology, the road load extraction of the shock absorber can quickly respond to the update and iteration of the shock absorber performance parameters, improve the simulation efficiency, save the development cost of the shock absorber durability performance, and shorten the product development cycle.

[0051] (5) This invention proposes a method for extracting lateral forces and processing segmented loads under the motion state of the shock absorber. It takes into account the dynamic load transfer of other subsystems acting on the shock absorber assembly during vehicle operation, and simulates the road load change of the shock absorber more realistically, thus solving the road load input problem in the fatigue analysis and bench test of the shock absorber. Attached Figure Description

[0052] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a flowchart of the road load acquisition method for the shock absorber described in the embodiments of this application;

[0054] Figure 2 This is a flowchart of the road load analysis method for the shock absorber described in the embodiments of this application;

[0055] Figure 3 This is a schematic diagram of the overall structure and hard points of the object being analyzed in the embodiments of this application;

[0056] Figure 4 This is a schematic diagram of the decomposed load of the piston rod, the object of analysis in this application embodiment;

[0057] Figure 5 This is a schematic diagram of the decomposed load of the vibration damper cylinder, the object of analysis in this application embodiment;

[0058] Figure 6 This is a schematic diagram of the vibration damper cylinder movement in an embodiment of this application;

[0059] Figure 7 This is a schematic diagram of the discretization of the force region under the piston rod motion condition in the embodiments of this application;

[0060] Figure 8 This is a schematic diagram of the force exerted by the damper cylinder on the damper piston rod at the center point D of the damper guide in an embodiment of this application.

[0061] Figure 9This is a schematic diagram of the processing results of the load in the X direction at the center points of N1 discrete regions passing through point D under a certain characteristic road surface in an embodiment of this application;

[0062] Figure 10 This is a schematic diagram of the discretization of the force region under the motion condition of the damper cylinder in the embodiments of this application;

[0063] Figure 11 This is a schematic diagram of the force exerted by the piston rod on the damper cylinder at the center point F of the damper piston in this embodiment of the application.

[0064] Figure 12 This is a schematic diagram of the processing result of the load in the x-direction at the moving point of the shock absorber cylinder under a certain characteristic road surface in an embodiment of this application;

[0065] Figure 13 This is a schematic diagram of the system in the embodiments of this application;

[0066] In the diagram: 1. Vibration damper piston rod, 2. Vibration damper cylinder, 3. Spring seat, 4. Stabilizer bar connecting bracket, 5. Vibration damper bracket, 6. Vibration damper piston, 7. Vibration damper internal limiting pad, 8. Vibration damper guide, 9. Vibration damper bottom valve, 10. Controller, 11. Memory. Detailed Implementation

[0067] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While some embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this application. It should be understood that the drawings and embodiments of this application are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0068] like Figure 1 As shown in the embodiments of this application, a method for obtaining the road load of a shock absorber includes the following steps:

[0069] S11. Determine the hard points on the shock absorber assembly used for connection with other components under the suspension design conditions.

[0070] like Figure 3 As shown, in one possible implementation, under the suspension design state, the hard points connecting the shock absorber assembly to other components include: the upper point A of the shock absorber piston rod 1, the center point B (optional) of the spring seat 3, the center point C of the upper end face of the shock absorber cylinder 2, the center point D of the shock absorber guide 8, the center point E of the internal limiting pad 7 of the shock absorber, the center point F of the shock absorber piston 6, the point G (optional) on the stabilizer bar connecting bracket 4, the lower fixed center point I of the shock absorber cylinder 2, and the center point J (optional) of the shock absorber bracket 5.

[0071] S12. Establish the dynamic model of the shock absorber assembly.

[0072] In one possible implementation, based on the actual physical model and motion relationships of the shock absorber assembly, point-line constraints are established between the shock absorber piston rod 1 and the shock absorber cylinder 2 at the center point D of the shock absorber guide 8 and the center point F of the shock absorber piston 6, respectively. These constraints are applied to the shock absorber piston rod 1 and the shock absorber cylinder 2, with the direction of the straight line being the line connecting the upper point A of the shock absorber piston rod 1 and the lower fixed center point I of the shock absorber cylinder 2. This radial constraint ensures the degree of freedom of the shock absorber piston rod 1 and the shock absorber cylinder 2 along the axial direction. The point-line pair modeling of the shock absorber has the same degree of freedom as the traditional cylindrical pair modeling, solving the problem that the traditional cylindrical pair modeling method for shock absorbers cannot extract lateral forces. The damping of the shock absorber assembly is simulated using a damping force element acting between the shock absorber piston rod 1 and the shock absorber cylinder 2. The force element reflects the relationship between the relative motion velocity of the shock absorber piston rod 1 and the shock absorber cylinder 2 and the damping force.

[0073] S13. To obtain the dynamic load of the shock absorber piston rod 1, a local load coordinate system related to the dynamic load of each hard point on the shock absorber piston rod 1 in the shock absorber assembly dynamic model is established to characterize the accurate dynamic position and direction of the shock absorber piston rod 1 under the motion of the whole vehicle.

[0074] In one possible implementation, a local load coordinate system is established on the piston rod 1 of the damper assembly in the dynamic model of the damper assembly, relating to the dynamic load of each hard point of the piston rod 1. Specifically:

[0075] First, identify the hard points related to the dynamic load of the damper piston rod 1, including the upper point A of the damper piston rod 1, the center point D of the damper guide 8, the center point E of the internal limiting pad 7 of the damper, and the center point F of the damper piston 6.

[0076] Next, the local load coordinates for each hard point are established, specifically as follows:

[0077] Then, with the hard point as the origin, the vector formed by the lower fixed center point I of the shock absorber cylinder 2 and the upper point A of the shock absorber piston rod 1 is the Z-direction. The projection of the vehicle coordinate X-axis onto the Z-direction normal plane of the corresponding local load coordinate system is the X-direction, and the Y-direction is determined by the right-hand rule. The local load coordinate system moves with the movement of the shock absorber piston rod 1, ensuring that the load direction of the shock absorber piston rod in the static finite element calculation of the designed posture remains fixed with respect to the relative position and posture of the shock absorber piston rod.

[0078] S14. To obtain the dynamic load of the damper cylinder 2 (including the damper bracket 5), a local load coordinate system related to the dynamic load of each hard point on the damper cylinder 2 in the dynamic model of the damper assembly is established to characterize the accurate dynamic position and direction of the damper piston rod 1 under the motion of the entire vehicle. Specifically:

[0079] First, determine the hard points related to the dynamic load of the damper cylinder 2, including the center point B of the spring seat 3, the center point C of the upper end face of the damper cylinder 2, the center point D of the damper guide 8, the center point F of the damper piston 6, the point G on the stabilizer bar connecting bracket 4, the lower center point H of the damper bottom valve 9, and the lower fixed center point I of the damper cylinder 2.

[0080] Next, the local load coordinates for each hard point are established, specifically as follows:

[0081] With the hard point as the origin, the vector formed by the lower fixed center point I of the shock absorber cylinder 2 and the upper point A of the shock absorber piston rod 1 is the Z direction, the projection of the vehicle coordinate X axis onto the Z direction normal plane of the corresponding local load coordinate system is the X direction, and the Y direction is determined by the right-hand rule.

[0082] S15. To obtain the stroke change during the vibration damper's movement, the displacement output between the upper point A of the vibration damper piston rod 1 and the lower fixed center point I of the vibration damper cylinder 2 is set in the vibration damper assembly dynamic model. To obtain the load on the vibration damper piston rod 1, the force and torque outputs on the vibration damper piston rod 1 are set in the established local load coordinate system.

[0083] like Figure 4 As shown, in one possible implementation, the force and torque output of the damper piston rod 1 are set in the local load coordinate system, specifically including:

[0084] The forces acting on the damper piston rod 1 at point A (support force), Fp1; the forces acting on the damper cylinder at point D (center of the damper guide 8), Fp2; the forces acting on the limiting ring at point E (center of the damper internal limiting pad 7), Fp3; the forces acting on the damper cylinder at point F (center of the damper piston 6), Fp4; and the damping force Fp5 at point F (center of the damper piston 6). The local load coordinate system is the same as the local load coordinate system established in step S13.

[0085] To obtain the load on the damper cylinder 2, the output of the force and torque on the damper cylinder 2 is set in the local load coordinate system.

[0086] like Figure 5 As shown, in one possible implementation, the output of the force and torque acting on the damper cylinder 2 is set, specifically including:

[0087] The following forces are applied: spring force Ft1_opt (optional) at the center point B of spring seat 3; buffer block force (optional) Ft2 at the center point C of the upper end face of damper cylinder 2; damper piston rod force Ft3 and damping force Ft7 at the center point D of damper guide 8; damper piston rod force Ft4 at the center point F of damper piston 6; stabilizer rod connecting bracket force Ft6_opt (optional) at point G on stabilizer rod connecting bracket 4; damping force Ft5 at the center point H of damper bottom valve 9; and force Ft8 at the lower fixed center point I of damper cylinder 2. The local load coordinate system is the local load coordinate system established in step S14.

[0088] It should be noted that steps S11-S15 use model templates to highly abstract the topological relationships of the shock absorber assemblies of various suspension types, such as MacPherson strut suspension, double wishbone suspension, multi-link suspension, torsion beam suspension, and leaf spring suspension. At the same time, standardized modeling and output ensure the universal applicability of this method.

[0089] S16. Establish a multi-body dynamics model of the whole vehicle integrating the suspension, body, powertrain, braking system, steering system, tire system, etc. This is existing technology and will not be described in detail here.

[0090] S17. Connect the vehicle multibody dynamics model with the shock absorber assembly dynamics model via communication; apply the virtual road test field simulation method to simulate the response of each system of the vehicle under various virtual road surface excitations, and output the displacement between the upper point A of the shock absorber piston rod 1 and the lower fixed center point I of the shock absorber cylinder 2 as defined in step S15, the force and torque on the shock absorber piston rod 1, and the force and torque on the shock absorber cylinder 2, thus obtaining the data related to the road load of the shock absorber assembly. All response outputs are functions of time t.

[0091] like Figure 2 As shown in the embodiments of this application, a road load analysis method for a shock absorber includes the following steps:

[0092] The road load acquisition method for the shock absorber as described in the embodiments of this application is used to obtain data related to the road load of the shock absorber assembly;

[0093] Dynamic load processing is applied to two time-varying force regions during the operation of the vibration damper: one is the region where the vibration damper cylinder 2 acts on the vibration damper piston rod 1 at the center point D of the vibration damper guide 8; the other is the region where the vibration damper piston rod 1 acts on the vibration damper cylinder at the center point F of the vibration damper piston 6.

[0094] To obtain the loads on the moving point of the shock absorber piston rod at the center point D (hereinafter referred to as point D) of the shock absorber guide during the shock absorber's movement (i.e., when there is relative movement between the shock absorber piston rod 1 and the shock absorber cylinder 2, different positions of the shock absorber piston rod 1 will pass through point D, and these points that pass through point D and are at different positions on the shock absorber piston rod 1 are considered moving points), and the moving point of the shock absorber cylinder at the center point F (hereinafter referred to as point F) of the shock absorber piston (i.e., when there is relative movement between the shock absorber piston rod 1 and the shock absorber cylinder 2, different positions of the shock absorber cylinder 2 will pass through point F, and these points that pass through point F and are at different positions on the shock absorber cylinder 2 are considered moving points). As the vehicle moves in real time, the aforementioned moving points exhibit step-time-varying force characteristics. This method discretizes the time-varying regions of the shock absorber piston rod 1 and the shock absorber cylinder 2, and determines the force region of the moving points in real time based on the shock absorber's travel. The continuous road load spectrum is multiplied by a preset square wave function (specifically, Formulas 1 and 2 below) to obtain the force conditions of each moving point in the shock absorber piston rod's movement region (referring to a series of moving points on the shock absorber piston rod passing through point D, i.e., a series of center points of the N1 discrete regions) and each moving point in the shock absorber cylinder's movement region (referring to a series of moving points on the shock absorber cylinder 2 passing through point F, i.e., a series of center points of the N2 discrete regions).

[0095] The advantage of this method lies in providing a dynamic lateral force extraction method for shock absorbers. On the one hand, it avoids the problems mentioned in the literature "Modeling and Application of Flexible Shock Absorbers for MacPherson Suspension Performance Development," which involves establishing contact and shock absorber flexibility, increasing model complexity, reducing simulation efficiency, and causing poor accuracy of lateral force due to the influence of the step function in the contact force. On the other hand, the load input affecting fatigue calculation is mainly the load amplitude information. Although the preset square wave function used in this invention is not differentiable at the start and end points, it does not cause a large change in the load amplitude, ensuring the accuracy of the load input in the fatigue calculation results.

[0096] In one possible implementation, the dynamic load handling of the time-varying region of the damper piston rod specifically includes:

[0097] S21. Discretize the force-bearing area of ​​the shock absorber piston rod. Statistically calculate the travel distance of the shock absorber piston rod on each road surface, denoted as Lp. During the vehicle's movement, the area formed by the movement of the shock absorber piston rod 1 relative to the shock absorber guide 8 is taken as the discrete object. The center point position of the shock absorber piston rod 1's movement area in the vehicle's ready state (see...) Figure 7 The center point p of region 1 p1-1Using the origin as the reference point, along the axis of the shock absorber piston rod, divide the area into N1 (in one possible implementation, N1 = 7) equal parts with a thickness of T1 (in one possible implementation, T1 = 20 mm). Note that N1 = 7 here is not a fixed value and can be adjusted according to the analysis accuracy and efficiency. This is just a method example. Figure 7 As shown. Record and output the coordinates of the center point of each discrete region as the loading point for the damper piston rod fatigue calculation in step S3.

[0098] S22. The force Fp2 exerted by the damper cylinder on the damper piston rod at the center point D of the damper guide 8 output in step S17 is distributed to N1 discrete regions. For discrete regions i∈[1,N1], we have:

[0099]

[0100] Where Fp2(t) is the force exerted by the damper cylinder on the damper piston rod at the center point D of the damper guide at time t;

[0101] Fp2 i Fp2(t) represents the force distributed into the i-th discrete region of the damper piston rod at time t.

[0102] Lp(t) represents the stroke of the shock absorber piston rod at time t;

[0103] Lp min This represents the minimum stroke of the shock absorber piston rod.

[0104] Therefore, the force exerted by the damper cylinder on the damper piston rod at the center point D of the N1 discrete region damper guides can be obtained. Figure 9 This example illustrates the processing results of the load in the X direction at the center points of N1 discrete regions passing through point D under a certain characteristic road surface in this invention.

[0105] In one possible implementation, such as Figure 8 As shown, the force Fp2 exerted by the damper cylinder on the damper piston rod at the center point D of the damper guide output in step S17 is distributed to 7 discrete regions.

[0106] S23. Combine the load spectrum of each fixed point of the shock absorber piston rod (except for the center point D of the piston rod guide) output in step S17 with the road load at the center point of the N1 discrete regions obtained in step S21, and output the road load file of the shock absorber piston rod 1.

[0107] In one possible implementation, the 18-channel load spectrum of each fixed point (including the upper point A of the piston rod, the center point E of the limiting pad, and the center point F of the piston) output in step S17 is combined with the 42-channel load spectrum of 7 discrete regions obtained in step S22 (i.e., each discrete region outputs 3 forces and 3 moments, counted as 6 channels, and the center point F of the piston inside the damper, 6 channels; totaling 18 channels; some channels may have zero moments, but the corresponding channels are still output) to output a damper piston rod road spectrum load file, totaling 60 channels.

[0108] like Figure 6 As shown, in one possible implementation, the dynamic load is handled in the time-varying region of the damper cylinder:

[0109] In step S15, the force Ft4 acting on the damper cylinder by the damper piston rod at the center point F of the damper piston is considered. The force area is continuous and variable as the damper's stroke changes. For example, when the damper's stroke is Lt(t0), the distance from the center point of the action area (i.e., point F) to the center point D of the damper guide is Lt(t0); when the damper's stroke is Lt(t1), the distance from the center point of the action area (i.e., point F) to the center point D of the damper guide is Lt(t1).

[0110] S31. Discretize the stress area of ​​the shock absorber cylinder. Statistically analyze the piston rod travel of the shock absorber on various road surfaces. During the vehicle's movement, the area formed by the shock absorber cylinder relative to the shock absorber piston (i.e., the shock absorber cylinder's travel area within the shock absorber's stroke) is taken as the discrete object. The center point position of the shock absorber cylinder's travel area in the vehicle's prepared state (e.g., ...) Figure 10 The center point P of region 1 t1-1 Taking the origin as the starting point, along the axis of the shock absorber cylinder, divide the area into N2 equal parts with a thickness of T2. See [reference needed]. Figure 10 Record and output the center point coordinates of each discrete region as the loading point for the fatigue calculation of the damper cylinder in step S3.

[0111] In one possible implementation, the region with a thickness of T2 = 20 mm is uniformly divided into N2 = 7 equal parts. Note that N2 = 7 is not a fixed value and can be adjusted according to the analysis accuracy and efficiency. This is just a method example; see [link to example]. Figure 10 Record and output the center point coordinates of each discrete region as the loading point for the damper cylinder fatigue calculation in step S3.

[0112] S32. The force Ft4 exerted by the piston rod at the center point F of the damper piston output in step S17 on the damper cylinder is as follows: Figure 11 As shown, the regions are respectively assigned to the N2 discrete regions described in step S31. For regions j∈[1,N2], we have:

[0113]

[0114] in:

[0115] Ft4(t) is the force exerted by the piston rod on the damper cylinder at the center point F of the damper piston at time t.

[0116] Ft4 j (t) represents the force distributed onto the damper cylinder at time t;

[0117] Lt(t) represents the motion stroke of the damper cylinder at time t;

[0118] Lt min This represents the minimum travel distance of the damper cylinder.

[0119] This allows us to obtain the force Ft4 acting on the damper cylinder at the center point F of the damper piston in N2 discrete regions.

[0120] In one possible implementation, such as Figure 12 As shown, this is the result of processing the load in the x-direction at the moving point of the shock absorber cylinder under a certain characteristic road surface.

[0121] S33. Combine the road loads at each fixed point of the shock absorber cylinder (except for the center point F of the shock absorber piston) output in step S17 with the N2 discrete area road loads obtained in step S32, and output the road load file of the shock absorber cylinder.

[0122] In one possible implementation, the 36-channel load spectrum (which represents the output of 3 forces and 3 moments at 6 fixed points) of the shock absorber cylinder output in step S17 is merged with the 42-channel load spectrum of 7 discrete regions obtained in step S32, and the road spectrum load file of the shock absorber cylinder is output.

[0123] In this embodiment, road load can be applied to fatigue analysis and calculation of the shock absorber piston rod and shock absorber cylinder, as well as bench test verification.

[0124] The road loads output in steps S23 and S33 can be applied to apply road spectrum loads to the piston rod and cylinder of the shock absorber at the positions described in steps S13, S14, S21, and S31 for fatigue calculation, and can also be used for bench test verification.

[0125] like Figure 13 As shown in the embodiments of this application, a road load acquisition system for a shock absorber includes a memory and a controller. The memory stores a computer-readable program, which, when invoked by the controller, can execute the steps of the road load acquisition method for the shock absorber as described in the embodiments of this application.

[0126] like Figure 13 As shown in the embodiments of this application, a road load analysis system for a shock absorber includes a memory and a controller. The memory stores a computer-readable program, which, when invoked by the controller, can execute the steps of the road load analysis method for the shock absorber as described in the embodiments of this application.

[0127] In this application embodiment, a storage medium stores a computer-readable program that, when invoked, can execute the steps of the road load acquisition method for a shock absorber as described in this application embodiment.

[0128] In this application embodiment, a storage medium stores a computer-readable program that, when invoked, can execute the steps of the road load analysis method for shock absorbers as described in this application embodiment.

[0129] It should be noted that the descriptions of the various embodiments above tend to emphasize the differences between them, while their similarities or commonalities can be referred to interchangeably. The descriptions of the storage medium, computer program, and computer program product embodiments above are similar to the descriptions of the method embodiments above, and have similar beneficial effects. For technical details not disclosed in the storage medium, computer program, and computer program product embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0130] It should be noted that the descriptions of the above storage medium and electronic device embodiments are similar to the descriptions of the above method embodiments, and have similar beneficial effects. For technical details not disclosed in the storage medium and electronic device embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0131] The aforementioned processor can be at least one of the following: target application integrated circuit, digital signal processor, digital signal processing device, programmable logic device, field-programmable gate array, central processing unit, controller, microcontroller, and microprocessor. It is understood that the electronic device implementing the above processor function can also be other types, and the embodiments of this application do not specifically limit it.

[0132] The aforementioned storage medium / memory can be a read-only memory, a programmable read-only memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, a magnetic random access memory, a flash memory, a magnetic surface memory, an optical disc, or a read-only optical disc, etc.; it can also be various terminals that include one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc.

[0133] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above steps / processes do not imply a sequential order of execution; the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above embodiments of this application are merely descriptive and do not represent the superiority or inferiority of the embodiments.

[0134] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0135] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory, magnetic disks, or optical disks.

[0136] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for obtaining road load on a vibration damper, characterized in that: The method includes the following steps: Identify the hard points where the shock absorber assembly connects to other components in the suspension design state; The dynamic model of the shock absorber assembly is established as follows: According to the actual physical model and motion relationship of the shock absorber assembly, point-line pair constraints are established between the shock absorber piston rod (1) and the shock absorber cylinder (2) at the center point D of the shock absorber guide (8) and the center point F of the shock absorber piston (6), respectively. The direction of the straight line is the direction of the line connecting the upper point A of the shock absorber piston rod (1) and the lower fixed center point I of the shock absorber cylinder (2). The damping of the shock absorber assembly is simulated by the damping force element acting between the shock absorber piston rod (1) and the shock absorber cylinder (2). In the dynamic model of the damper assembly, a local load coordinate system is established on the damper piston rod (1) to be related to the dynamic load of each hard point; In the dynamic model of the shock absorber assembly, a local load coordinate system is established on the shock absorber cylinder (2) to be related to the dynamic load of each hard point; In the dynamic model of the shock absorber assembly, the displacement output between the upper point A of the shock absorber piston rod (1) and the lower fixed center point I of the shock absorber cylinder (2) is set. In the established load coordinate system, the output of the force and torque of the shock absorber piston rod (1) is set, as well as the output of the force and torque of the shock absorber cylinder (2). Establish a multibody dynamics model for the entire vehicle; The vehicle multibody dynamics model is connected to the shock absorber assembly dynamics model for communication, simulating the response of each system of the vehicle under various virtual road surface excitations, and outputting data related to the road load of the shock absorber assembly, including the displacement between the upper point A of the shock absorber piston rod (1) and the lower fixed center point I of the shock absorber cylinder, the force and torque on the shock absorber piston rod (1), and the force and torque on the shock absorber cylinder (2).

2. The method for obtaining road load of a shock absorber according to claim 1, characterized in that: In the suspension design state, the hard points where the shock absorber assembly connects with other components include: the upper point A of the shock absorber piston rod (1), the center point C of the upper end face of the shock absorber cylinder (2), the center point D of the shock absorber guide (8), the center point E of the internal limiting pad (7) of the shock absorber, the center point F of the shock absorber piston (6), and the lower fixed center point I of the shock absorber cylinder (2).

3. The method for obtaining road load of a shock absorber according to claim 2, characterized in that: In the suspension design state, the hard points where the shock absorber assembly connects with other components also include: the center point B of the spring seat (3), the point G on the stabilizer bar connecting bracket (4), and the center point J of the shock absorber bracket (5).

4. The method for obtaining road load of a vibration damper according to claim 2, characterized in that: In the dynamic model of the shock absorber assembly, a local load coordinate system is established on the piston rod (1) of the shock absorber, which is related to the dynamic load of the piston rod (1). Specifically: Determine the hard points related to the dynamic load of the damper piston rod (1), including the upper point A of the damper piston rod (1), the center point D of the damper guide (8), the center point E of the damper internal limiting pad (7), and the center point F of the damper piston (6). Establish the local load coordinates for each hard point. Specifically, with the hard point as the origin, the vector formed by the lower fixed center point I of the damper cylinder (2) and the upper point A of the damper piston rod (1) is the Z direction. The projection of the vehicle coordinate X axis onto the Z direction normal plane of the corresponding local load coordinate system is the X direction. The Y direction is determined by the right-hand rule.

5. The method for obtaining road load of a vibration damper according to claim 3, characterized in that: In the dynamic model of the shock absorber assembly, a local load coordinate system is established on the shock absorber cylinder (2) to relate to the dynamic load of each hard point, specifically as follows: Determine the hard points related to the dynamic load of the damper cylinder (2), including the center point B of the spring seat (3), the center point C of the upper end face of the damper cylinder (2), the center point D of the damper guide (8), the center point F of the damper piston (6), the point G on the stabilizer bar connecting bracket (4), the lower center point H of the bottom valve (9) of the damper cylinder, and the lower fixed center point I of the damper cylinder (2); Establish the local load coordinates for each hard point. Specifically, with the hard point as the origin, the vector formed by the lower fixed center point I of the damper cylinder (2) and the upper point A of the damper piston rod (1) is the Z direction. The projection of the vehicle coordinate X axis onto the Z direction normal plane of the corresponding local load coordinate system is the X direction. The Y direction is determined by the right-hand rule.

6. The method for obtaining road load of a shock absorber according to claim 1, characterized in that: The vehicle multibody dynamics model integrates the suspension, body, powertrain, braking system, steering system, and tire system.

7. A method for analyzing road loads on vibration dampers, characterized in that: Includes the following steps: Data related to the road load of the shock absorber assembly obtained by the road load acquisition method for the shock absorber as described in any one of claims 1 to 6; The dynamic load of the time-varying region of the shock absorber piston rod (1) and the shock absorber cylinder (2) is processed as follows: the time-varying region of the shock absorber piston rod (1) and the shock absorber cylinder (2) is discretized, and the force region of the moving point is determined in real time according to the movement stroke of the shock absorber. The continuous road load spectrum is multiplied with the preset square wave function to obtain the force conditions of each moving point in the movement region of the shock absorber piston rod (1) and each moving point in the movement region of the shock absorber cylinder (2).

8. The road load analysis method for the vibration damper according to claim 7, characterized in that: The dynamic load treatment for the time-varying region of the damper piston rod (1) is as follows: Discretize the force-bearing area of ​​the shock absorber piston rod (1) and count the stroke of the shock absorber piston rod (1) on each road surface; The area formed by the movement of the shock absorber piston rod (1) relative to the shock absorber guide (8) during the movement of the whole vehicle is taken as a discrete object; Taking the upper center point of the movement area of ​​the shock absorber piston rod (1) in the vehicle preparation state as the origin, along the axis of the shock absorber piston rod (1), it is uniformly divided into discrete regions of N1 equal parts with thickness T1. Record and output the coordinates of the center point of each discrete region; The force exerted by the damper cylinder (2) at the center point D of the output damper guide (8) on the damper piston rod (1) is distributed to N1 discrete regions to obtain the force exerted by the damper cylinder (2) at the center point D of the damper guide (8) in N1 discrete regions. The load spectrum of each fixed point of the damper piston rod except the center point D of the damper guide (8) is combined with the road load at the center point of N1 discrete regions to output the road load file of the damper piston rod (1).

9. The road load analysis method for the vibration damper according to claim 7, characterized in that: The dynamic load treatment for the time-varying region of the damper cylinder (2) is as follows: Discretize the stress area of ​​the shock absorber cylinder (2) and count the stroke of the piston rod (1) of each road surface shock absorber; The area formed by the movement of the shock absorber cylinder (2) relative to the shock absorber piston (6) during the movement of the whole vehicle is taken as a discrete object; Taking the center point of the moving area of ​​the shock absorber cylinder (2) in the vehicle preparation state as the origin, along the axis of the shock absorber cylinder (2), the area is evenly divided into N2 equal parts with a thickness of T2. Record and output the coordinates of the center point of each discrete region; The force exerted by the piston rod (1) of the output damper piston at the center point F on the damper cylinder (2) is distributed to N2 discrete regions, resulting in N2 discrete regions of the force exerted by the piston piston (6) at the center point F on the damper cylinder (2). The load spectrum of each fixed point of the damper cylinder (2) except the center point F of the damper piston is combined with the road load of N2 discrete regions to output the road load file of the damper cylinder (2).

10. A road load acquisition system for a vibration damper, characterized in that: It includes a memory and a controller, wherein the memory stores a computer-readable program that, when invoked by the controller, can perform the steps of the road load acquisition method for the shock absorber as described in any one of claims 1 to 6.

11. A road load analysis system for a vibration damper, characterized in that: It includes a memory and a controller, wherein the memory stores a computer-readable program that, when invoked by the controller, can perform the steps of the road load analysis method for the shock absorber as described in any one of claims 7 to 9.

12. A storage medium, characterized in that: It contains a computer-readable program that, when invoked, performs the steps of the road load acquisition method for the shock absorber as described in any one of claims 1 to 6.

13. A storage medium, characterized in that: It contains a computer-readable program that, when invoked, performs the steps of the road load analysis method for the shock absorber as described in any one of claims 7 to 9.

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