Subframe local rigidity determination method, device and equipment and readable storage medium

Abstract

The method, apparatus, equipment, and readable storage medium for determining the local stiffness of the subframe are as follows: First, the KC characteristic design target of the target suspension is obtained, and the overall stiffness design requirements of the suspension system to ensure that the KC characteristics meet the target are determined. Then, a suspension rigid body simulation model is constructed to shield the stiffness deformation effects of the suspension links, steering knuckles, and non-bushing components of the subframe. The bushing stiffness parameters at each connection position of the suspension are decoupled and locked with the KC characteristic design target as a constraint. Then, based on the stiffness series equivalence relationship, the local stiffness at the connection position between the subframe and the suspension links is equivalent to an equivalent elastic element connected in series on the suspension force transmission path. With the overall stiffness design requirements of the suspension system as a constraint, the initial target value of the local stiffness of the subframe is obtained by inverse solution in combination with the locked bushing stiffness parameters. Finally, a suspension simulation model including the equivalent subframe stiffness is constructed. Through KC characteristic simulation verification and iterative correction under the target working condition, the final target value of the local stiffness of the subframe is locked.

Description

Technical Field

[0001] This application relates to the field of automotive chassis, specifically to a method, apparatus, device, and readable storage medium for determining the local stiffness of a subframe. Background Technology

[0002] With the rapid development of the automotive industry, users' performance requirements for vehicle handling stability and ride comfort are continuously increasing. Suspension KC characteristics, as a core indicator determining the overall chassis handling and ride comfort performance, directly impact the final chassis performance. The subframe, as a key load-bearing component of the suspension system, has a significant impact on the realization of suspension KC characteristics due to the local stiffness of its mounting points. In the forward development process of automotive chassis, accurately determining the subframe stiffness target in the early design stages is a core requirement for ensuring that suspension KC characteristics meet standards, improving development efficiency, and shortening the development cycle.

[0003] In related technologies, the determination of subframe stiffness targets is usually carried out after the detailed structural design of the subframe is completed. This is done by establishing a corresponding finite element model, combining KC characteristic simulation analysis, verifying the impact of subframe stiffness on suspension KC performance, and iteratively optimizing the subframe structure or stiffness parameters based on the verification results.

[0004] However, this approach requires the completion of a detailed subframe structural design and can only verify and iteratively optimize the stiffness against KC characteristics after the structure is formed. It cannot proactively lock the local stiffness target of the subframe mounting point based on the suspension KC characteristic target in the early stages of chassis forward development and before the subframe structure is designed. It is prone to causing the suspension hard point to be adjusted and the structure to be repeatedly modified due to insufficient stiffness after forming, which will greatly increase the development cost and workload, prolong the development cycle, and cannot meet the requirements of efficient forward development of the chassis. Summary of the Invention

[0005] This application provides a method, apparatus, device, and readable storage medium for determining the local stiffness of a subframe, which can solve the technical problems existing in related technologies, such as the inability to positively lock the local stiffness target of the subframe based on the suspension KC characteristic target in the early stage of chassis forward development and before the subframe structure is designed, which leads to repeated design changes, long development cycles, and high costs.

[0006] In a first aspect, embodiments of this application provide a method for determining the local stiffness of a subframe, the method comprising: Obtain the KC characteristic design target of the target suspension and determine the overall stiffness design requirements of the suspension system; Construct a rigid body simulation model of the suspension, and determine the bushing stiffness parameters at each connection position of the suspension based on the KC characteristic design objective. Based on the overall stiffness design requirements and the bushing stiffness parameters, the initial target value of the local stiffness of the subframe is determined through the stiffness series equivalent relationship. Based on the initial target value of the subframe local stiffness, a suspension simulation model including the equivalent subframe stiffness is constructed. The final target value of the subframe local stiffness is corrected and locked through KC characteristic simulation verification.

[0007] In conjunction with the first aspect, in one implementation, obtaining the KC characteristic design target of the target suspension and determining the overall stiffness design requirements of the suspension system includes: Based on the chassis handling performance requirements of the target vehicle, determine the design threshold range of the suspension KC characteristics; Based on the design threshold range of the KC characteristic, the total stiffness design requirements of the suspension system under the corresponding working conditions are determined. The total stiffness design requirements are the series total stiffness thresholds of the suspension system required to ensure that the KC characteristic meets the standards.

[0008] In conjunction with the first aspect, in one implementation, the step of constructing a suspension rigid body simulation model and determining the bushing stiffness parameters at each connection point of the suspension based on the KC characteristic design objective includes: A rigid body simulation model of the suspension system is constructed, and the suspension linkage, steering knuckle, and subframe are all set as rigid body elements to shield the stiffness deformation effects of non-bushing components. With the goal of achieving the KC characteristic design objective as the optimization objective, the bushing stiffness parameters at each connection node of the suspension are adjusted and determined, and the bushing stiffness design value is locked.

[0009] In conjunction with the first aspect, in one implementation, determining the initial target value of the subframe local stiffness based on the overall stiffness design requirements and the bushing stiffness parameters, through a stiffness series equivalent relationship, includes: The local stiffness at the connection point between the subframe and the suspension rods is equivalent to an equivalent elastic element connected in series along the suspension force transmission path; Based on the force transmission path of the suspension system, the series stiffness relationship between the equivalent elastic element and the corresponding bushing is determined. To meet the overall stiffness design requirements, and in conjunction with the locked bushing stiffness parameters, the stiffness threshold of the equivalent elastic element is determined as the initial target value for the local stiffness of the subframe.

[0010] In conjunction with the first aspect, in one implementation, constructing a suspension simulation model including equivalent subframe stiffness based on an initial target value of the subframe local stiffness includes: Based on the suspension rigid body simulation model, a rigid body transformation unit is added at the connection position between the suspension rod and the subframe; The suspension members are connected to the rigid body conversion unit through bushing units with locked stiffness at corresponding positions, and the rigid body conversion unit is connected to the subframe through equivalent elastic units representing the local stiffness of the subframe. The initial target value of the local stiffness of the subframe is assigned to the equivalent elastic element to complete the construction of the suspension simulation model including the stiffness of the equivalent subframe.

[0011] In conjunction with the first aspect, in one embodiment, the subframe local stiffness includes multiple sets of local stiffness at the connection nodes between the subframe and each suspension member; For each suspension connection node of the subframe, the corresponding bushing stiffness parameter locking, equivalent elastic element stiffness calculation, and simulation verification correction steps are performed to determine the final target value of the local stiffness of the subframe corresponding to each connection node.

[0012] In conjunction with the first aspect, in one embodiment, the subframe local stiffness includes multiple sets of local stiffness at the connection nodes between the subframe and each suspension member; For each suspension connection node of the subframe, the corresponding bushing stiffness parameter locking, equivalent elastic element stiffness calculation, and simulation verification correction steps are performed to determine the final target value of the local stiffness of the subframe corresponding to each connection node.

[0013] Secondly, embodiments of this application provide a subframe local stiffness determination device, the subframe local stiffness determination device comprising: The target determination module is used to obtain the KC characteristic design target of the target suspension and determine the overall stiffness design requirements of the suspension system. The bushing stiffness calibration module is used to construct a suspension rigid body simulation model and determine the bushing stiffness parameters at each connection position of the suspension based on the KC characteristic design target. The stiffness target calculation module is used to determine the initial target value of the local stiffness of the subframe based on the total stiffness design requirements and the bushing stiffness parameters, through the stiffness series equivalent relationship. The simulation verification and locking module is used to construct a suspension simulation model containing equivalent subframe stiffness based on the initial target value of the subframe local stiffness, and to correct and lock the final target value of the subframe local stiffness through KC characteristic simulation verification.

[0014] Thirdly, embodiments of this application provide a subframe local stiffness determination device, the subframe local stiffness determination device including a processor, a memory, and a subframe local stiffness determination program stored in the memory and executable by the processor, wherein when the subframe local stiffness determination program is executed by the processor, the steps of the subframe local stiffness determination method as described in some of the above embodiments are implemented.

[0015] Fourthly, embodiments of this application provide a computer-readable storage medium storing a subframe local stiffness determination program, wherein when the subframe local stiffness determination program is executed by a processor, it implements the steps of the subframe local stiffness determination method as described in some of the above embodiments.

[0016] The beneficial effects of the technical solutions provided in this application include: First, the KC characteristic design target of the target suspension is obtained, and the overall stiffness design requirements of the suspension system to ensure that the KC characteristics meet the target are determined. Then, a suspension rigid body simulation model is constructed to shield the stiffness deformation effects of non-bushing components of the suspension links, steering knuckles, and subframe. The bushing stiffness parameters at each connection position of the suspension are decoupled and locked with the KC characteristic design target as a constraint. Then, based on the stiffness series equivalence relationship, the local stiffness at the connection position between the subframe and the suspension links is equivalent to an equivalent elastic element connected in series on the suspension force transmission path. With the overall stiffness design requirements of the suspension system as a constraint, the initial target value of the local stiffness of the subframe is obtained by reverse solving in combination with the locked bushing stiffness parameters. Finally, a suspension simulation model including the equivalent subframe stiffness is constructed. Through KC characteristic simulation verification and iterative correction under the target working condition, the final target value of the local stiffness of the subframe is locked. This allows for the forward and accurate determination of the local stiffness target of the subframe in the early stage of the project when there is no detailed structural design of the subframe. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating an embodiment of the method for determining the local stiffness of the subframe in this application; Figure 2 This is a diagram showing the proportion of suspension system stiffness composition in an embodiment of the method for determining the local stiffness of the subframe in this application. Figure 3 This is a schematic diagram illustrating the original connection method between the suspension members and the subframe in one embodiment of the method for determining the local stiffness of the subframe in this application. Figure 4 This is a schematic diagram of the stiffness of the suspension members and the improved connection method of the subframe to increase the equivalent subframe stiffness, according to an embodiment of the method for determining the local stiffness of the subframe in this application. Figure 5 This is a schematic diagram of the hardware structure of the subframe local stiffness determination device involved in the embodiments of this application. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0019] It's important to understand that with the rapid development of the automotive industry, users' performance requirements for vehicle handling stability and ride comfort are continuously increasing. Suspension KC characteristics, as a core indicator determining the overall chassis handling and ride comfort performance, directly impact the final chassis performance. The subframe, as a key load-bearing component of the suspension system, has a significant impact on the realization of suspension KC characteristics due to the local stiffness of its mounting points. In the forward development process of automotive chassis, accurately determining the subframe stiffness target in the early design stages is a core requirement for ensuring that suspension KC characteristics meet standards, improving development efficiency, and shortening the development cycle.

[0020] Suspension KC characteristics: This is a collective term for the kinematic characteristics (K characteristics) and compliance characteristics (C characteristics, also known as elastic kinematic characteristics) of automotive suspension. It is a core design indicator for the forward development of automotive chassis and directly determines the vehicle's handling stability, ride comfort, tire contact with the ground, steering feel, and tire wear characteristics.

[0021] In particular, the determination of the subframe stiffness target is usually carried out after the detailed structural design of the subframe is completed. This is done by establishing a corresponding finite element model, combining KC characteristic simulation analysis, verifying the impact of subframe stiffness on suspension KC performance, and iteratively optimizing the subframe structure or stiffness parameters based on the verification results.

[0022] However, this approach requires the completion of a detailed subframe structural design and can only verify and iteratively optimize the stiffness against KC characteristics after the structure is formed. It cannot proactively lock the local stiffness target of the subframe mounting point based on the suspension KC characteristic target in the early stages of chassis forward development and before the subframe structure is designed. It is prone to causing the suspension hard point to be adjusted and the structure to be repeatedly modified due to insufficient stiffness after forming, which will greatly increase the development cost and workload, prolong the development cycle, and cannot meet the requirements of efficient forward development of the chassis.

[0023] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0024] This application provides a method, apparatus, device, and readable storage medium for determining the local stiffness of a subframe, which can solve the technical problems existing in related technologies, such as the inability to positively lock the local stiffness target of the subframe based on the suspension KC characteristic target in the early stage of chassis forward development and before the subframe structure is designed, which leads to repeated design changes, long development cycles, and high costs.

[0025] In a first aspect, embodiments of this application provide a method for determining the local stiffness of a subframe.

[0026] In one embodiment, reference is made to Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the method for determining the local stiffness of the subframe in this application. Figure 1 As shown, the method for determining the local stiffness of the subframe includes: S100: Obtain the KC characteristic design target of the target suspension and determine the overall stiffness design requirements of the suspension system; S200: Construct a rigid body simulation model of the suspension, and determine the bushing stiffness parameters at each connection position of the suspension based on the KC characteristic design objective; S300: Based on the total stiffness design requirements and the bushing stiffness parameters, the initial target value of the local stiffness of the subframe is determined through the stiffness series equivalent relationship; S400: Based on the initial target value of the subframe local stiffness, construct a suspension simulation model including the equivalent subframe stiffness, verify it through KC characteristic simulation, and correct and lock the final target value of the subframe local stiffness.

[0027] Among them, the suspension KC characteristic is a core performance indicator that determines the vehicle chassis handling stability and ride comfort. It is directly related to the total series stiffness on the force transmission path of the suspension system. In this embodiment, the KC characteristic design target of the target suspension is pre-locked in step S100, and the total stiffness design requirements of the suspension system required to ensure that the KC characteristic meets the standard are determined accordingly. This establishes a fixed performance constraint boundary for the subsequent stiffness parameter design, solution and verification throughout the entire process, ensuring that the determination of all stiffness parameters revolves around the core goal of meeting the KC characteristic, and fundamentally avoiding the problem of stiffness design being out of touch with the performance requirements of the whole vehicle.

[0028] Secondly, such as Figure 2As shown, based on the stiffness composition law of the suspension system, the stiffness of the suspension connecting bushings and the local stiffness of the subframe connection points are the core contributors to the overall flexibility of the suspension. The structural stiffness of the suspension links and steering knuckles has a very low impact on the overall deformation of the suspension and can be ignored. In this embodiment, a full rigid body simulation model of the suspension system is constructed through step S200. The suspension links, steering knuckles, and subframe are all set as rigid body elements without deformation, completely shielding the stiffness deformation interference of non-bushing components. The influencing factors of KC characteristics are completely decoupled to the bushing stiffness of each connection position of the suspension. Then, with the KC characteristic design goal as the optimization goal, the bushing stiffness parameters of each connection node of the suspension are calibrated and locked. The multivariable coupled stiffness system is transformed into a single-variable solution environment, providing a fixed known parameter basis for the subsequent accurate solution of the local stiffness of the subframe.

[0029] Then, in the force transmission path of the suspension system, the local stiffness of the connecting bushings at both ends of the suspension rod and the corresponding connection point of the subframe are in a series relationship in the same force flow path. The total stiffness of the series stiffness system follows the reciprocal summation law. In this embodiment, through step S300, the local stiffness of the subframe, which has no physical structure and cannot be directly quantified, is equivalent to an equivalent elastic element connected in series on the suspension force transmission path. The structural stiffness that cannot be directly calculated is transformed into a quantifiable parameter that can be included in the series stiffness calculation system. At the same time, the total stiffness design requirements of the suspension system pre-locked in step S100 are used as rigid constraints to ensure that the total series stiffness of the suspension system remains constant after the equivalent stiffness of the subframe is included. Then, the initial target value of the local stiffness of the subframe is obtained by reverse solving through the series stiffness relationship. This completely breaks through the limitation of the existing technology that requires the detailed structure of the subframe and the finite element model to determine the stiffness target, and realizes the forward solution of the stiffness target before the subframe structural design is carried out.

[0030] Finally, through step S400, a suspension simulation model including the equivalent subframe stiffness is constructed based on the aforementioned stiffness equivalence logic. This accurately reproduces the actual influence of the subframe local stiffness on the suspension KC characteristics. Through KC characteristic simulation analysis under target conditions, the conformity of the initial target value to the KC characteristic design requirements is verified. For cases that do not meet the design requirements, the stiffness parameters of the equivalent elastic element are iteratively adjusted and the simulation analysis is repeated to eliminate the deviation between the theoretical formula solution and the actual engineering application. Finally, the final target value of the subframe local stiffness that can meet the KC characteristic design requirements under all working conditions is locked, forming a complete design-verification-correction closed loop. This provides accurate and solidified stiffness design input for the subsequent detailed structural design of the subframe.

[0031] Through the steps described above in this embodiment, the determination of the subframe stiffness target can be moved forward to before the detailed structural design, breaking down the serial iteration barrier between suspension performance development and subframe structural design. This avoids problems such as suspension hard point adjustments and repeated design changes to suspension and subframe structural components caused by substandard local stiffness of the subframe from the source, significantly shortening the development cycle of the vehicle chassis, reducing development costs, and improving the accuracy and engineering adaptability of subframe stiffness design. It can fully adapt to the forward development scenarios of subframes for various passenger vehicle suspension structures.

[0032] Furthermore, in one embodiment, S100 includes the following steps: S101: Determine the design threshold range of the suspension KC characteristics based on the chassis handling performance requirements of the target vehicle; S102: Based on the design threshold range of the KC characteristic, determine the total stiffness design requirements of the suspension system under the corresponding working conditions. The total stiffness design requirements are the total stiffness threshold of the suspension system in series required to ensure that the KC characteristic meets the standard.

[0033] In this embodiment, the suspension KC characteristic refers to the variation characteristics of key handling performance indicators such as wheel alignment parameters, track width, and toe-in value of the vehicle suspension system under wheel vertical movement and steering conditions. It is a core performance indicator that determines the vehicle chassis handling stability and ride comfort. This step locks the design threshold range of the KC characteristic by the chassis handling performance requirements, and then determines the total series stiffness threshold of the suspension system. This provides a unique and fixed performance constraint boundary for subsequent bushing stiffness design and subframe stiffness solution, ensuring that the solution of all subsequent stiffness parameters revolves around the core goal of achieving the KC characteristic standard, and avoiding the disconnect between stiffness design and performance goals.

[0034] Furthermore, in one embodiment, step S200 includes the following steps: S201: Construct a rigid body simulation model of the suspension system, and set the suspension linkage, steering knuckle, and subframe as rigid body elements to shield the stiffness deformation effects of non-bushel components; S202: With the goal of achieving the KC characteristic design objective, adjust and determine the bushing stiffness parameters at each connection node of the suspension, and lock the bushing stiffness design value.

[0035] In this embodiment, combined with Figure 2The suspension stiffness composition shown indicates that the stiffness of the steering knuckle and suspension linkage has a very small impact on the overall suspension flexibility. The stiffness of the subframe is the target to be solved. Therefore, this step constructs a full rigid body simulation model to completely shield the structural deformation effects of the suspension linkage, steering knuckle, and subframe themselves. This completely decouples the influencing factors of the KC characteristic to the bushing stiffness at each connection point of the suspension. Thus, without interference from other structural stiffness, the bushing stiffness parameters that meet the KC characteristic design target can be accurately adjusted and locked, including the outer bushing stiffness K at the connection point between the suspension linkage and the steering knuckle. outer bush Stiffness K of the inner bushing on the side where the suspension rod connects to the subframe inner bush This provides fixed known stiffness parameters for solving the local stiffness of the subframe, and realizes the decoupled design of bushing stiffness and subframe stiffness.

[0036] Furthermore, in one embodiment, step S300 includes the following steps: S301: The local stiffness at the connection point between the subframe and the suspension rod is equivalent to an equivalent elastic element connected in series along the suspension force transmission path; S302: Based on the force transmission path of the suspension system, determine the series stiffness relationship between the equivalent elastic element and the corresponding bushing; S303: With the overall stiffness design requirement as a constraint, and in combination with the locked bushing stiffness parameters, determine the stiffness threshold of the equivalent elastic element as the initial target value of the local stiffness of the subframe.

[0037] In this embodiment, reference Figure 3 The original connection method between the suspension rods and the subframe shown in the diagram, in the original force transmission path, the series stiffness element between the steering knuckle, suspension rods, and subframe is only the outer bushing K. outer bush With inner lining K inner bush The total stiffness of its series connection satisfies the formula:

[0038] Where K total This refers to the total series stiffness threshold of the suspension system locked in step S100. To achieve stiffness calculation without a subframe structure, this step refers to... Figure 4 The improved connection method shown treats the local stiffness of the subframe connection point as equivalent to an equivalent elastic element connected in series along the force transmission path, namely the bushing element K representing the local stiffness of the subframe. subframe After reconstructing the force transmission path by adding a rigid body conversion unit, an outer bushing K is formed on the suspension force transmission path.outer bush Inner liner K inner bush Equivalent bushing K subframe In a three-unit series structure, to ensure that the total suspension stiffness remains constant before and after reconstruction and that the KC characteristic does not shift, the total series stiffness after reconstruction must satisfy the formula:

[0039] Based on the two series stiffness formulas mentioned above, combined with the already locked K... total K outer bush K inner bush K can be obtained by inversely solving the formula. subframe The value is the initial target value of the local stiffness of the subframe, which completely breaks through the limitation of existing technology that requires the detailed structure of the subframe to determine the stiffness target, and realizes the forward, structure-free pre-solution of the local stiffness target of the subframe.

[0040] Furthermore, in one embodiment, step S400 includes the following steps: S401: Based on the suspension rigid body simulation model, a rigid body transformation unit is added at the connection position between the suspension rod and the subframe; S402: Connect the suspension rods to the rigid body conversion unit through bushing units with locked stiffness at corresponding positions, and connect the rigid body conversion unit to the subframe through equivalent elastic units representing the local stiffness of the subframe. S403: Assign the initial target value of the local stiffness of the subframe to the equivalent elastic element to complete the construction of the suspension simulation model including the stiffness of the equivalent subframe.

[0041] In this embodiment, by adding a rigid body transformation unit, the stiffness series equivalent structure in step S300 is completely reproduced. The rigid body transformation unit is a rigid body component without deformation, which will not introduce additional stiffness influence or deformation interference. It can completely decouple the stiffness of the inner bushing from the equivalent stiffness of the subframe, ensuring that only the stiffness parameters of the equivalent elastic element in the model will affect the total stiffness and KC characteristics of the suspension. This accurately reproduces the effect of the local stiffness of the subframe on the KC characteristics of the suspension, providing an accurate and reliable simulation model basis for subsequent simulation verification and stiffness parameter correction, and ensuring that the simulation results can truly reflect the influence law of the local stiffness of the subframe on the KC characteristics.

[0042] Furthermore, in one embodiment, step S400 includes the following steps: S404: Using the suspension simulation model including the equivalent subframe stiffness, perform KC characteristic simulation analysis under the target working condition to obtain the simulation KC characteristic results; S405: Compare the simulation KC characteristic results with the preset KC characteristic design target to determine whether the design requirements are met; S406: If the design requirements are not met, adjust the stiffness parameters of the equivalent elastic element, repeat the KC characteristic simulation analysis until the simulation KC characteristic results meet the design requirements, and lock the corresponding stiffness parameters as the final target value of the local stiffness of the subframe.

[0043] In this embodiment, the suspension simulation model with equivalent subframe stiffness can be constructed to realistically simulate the actual impact of the local stiffness of the subframe on the suspension KC characteristics under target conditions. By comparing the simulation results with the preset KC characteristic design target, it can be verified whether the initial target value obtained by theoretical solution can meet the performance requirements under all conditions. For cases that do not meet the design requirements, the deviation between theoretical solution and actual simulation can be eliminated by iteratively adjusting the stiffness parameters of the equivalent elastic element and repeating the simulation verification. The final target value of the local stiffness of the subframe can be locked to ensure that the suspension KC characteristics meet the design requirements. This provides a precise and unique stiffness design input for the subsequent detailed structural design of the subframe, ensuring that after the subframe structural design is completed, there is no need to perform structural iteration and hard point adjustment due to the failure of KC characteristics.

[0044] Furthermore, in one embodiment, the subframe local stiffness includes multiple sets of local stiffness at the connection nodes between the subframe and each suspension member; for each suspension connection node of the subframe, the corresponding bushing stiffness parameter locking, equivalent elastic element stiffness calculation, and simulation verification correction steps are performed to determine the final target value of the subframe local stiffness corresponding to each connection node one by one.

[0045] In this embodiment, passenger vehicle suspension systems, especially multi-link rear suspensions, have multiple connection nodes between suspension links and the subframe. The degree and dimension of the impact of the local stiffness of each connection node on the suspension KC characteristics are different. By performing the entire process of bushing stiffness locking, equivalent stiffness solving, and simulation verification correction for each suspension connection node, the local stiffness target corresponding to each connection position of the subframe can be determined one by one and in detail. This achieves point-by-point and refined design of the local stiffness of the subframe, avoiding the problem that the overall stiffness target cannot adapt to the differentiated needs of each connection node. This greatly improves the engineering adaptability of this method and can fully cover the forward design scenarios of subframes for various passenger vehicle suspension structures.

[0046] Secondly, embodiments of this application also provide a device for determining the local stiffness of a subframe. The device includes: a target determination module, used to acquire the KC characteristic design target of a target suspension and determine the overall stiffness design requirements of the suspension system; a bushing stiffness calibration module, used to construct a suspension rigid body simulation model and, based on the KC characteristic design target, determine the bushing stiffness parameters at each connection position of the suspension; a stiffness target calculation module, used to determine the initial target value of the local stiffness of the subframe based on the overall stiffness design requirements and the bushing stiffness parameters, through a stiffness series equivalence relationship; and a simulation verification and locking module, used to construct a suspension simulation model containing equivalent subframe stiffness based on the initial target value of the local stiffness of the subframe, and, through KC characteristic simulation verification, correct and lock the final target value of the local stiffness of the subframe.

[0047] The functions of each module in the aforementioned subframe local stiffness determination device correspond to the steps in the aforementioned subframe local stiffness determination method embodiment, and their functions and implementation processes will not be described in detail here.

[0048] Thirdly, embodiments of this application provide a device for determining the local stiffness of a subframe. This device can be a personal computer (PC), a laptop computer, a server, or other device with data processing capabilities.

[0049] Reference Figure 5 , Figure 5 This is a schematic diagram of the hardware structure of the subframe local stiffness determination device involved in the embodiments of this application. In this embodiment, the subframe local stiffness determination device may include a processor, a memory, a communication interface, and a communication bus.

[0050] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0051] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces for interconnecting components within the subframe local stiffness determination device, as well as interfaces for interconnecting the subframe local stiffness determination device with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0052] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0053] The processor can be a general-purpose processor, which can call the subframe local stiffness determination program stored in the memory and execute the subframe local stiffness determination method provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the subframe local stiffness determination program is called can be referred to in the various embodiments of the subframe local stiffness determination method of this application, and will not be repeated here.

[0054] Those skilled in the art will understand that Figure 5 The hardware structure shown does not constitute a limitation of this application and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0055] Fourthly, embodiments of this application also provide a readable storage medium.

[0056] The present application has a readable storage medium storing a subframe local stiffness determination program, wherein when the subframe local stiffness determination program is executed by a processor, it implements the steps of the subframe local stiffness determination method as described above.

[0057] The method implemented when the subframe local stiffness determination procedure is executed can be referred to in various embodiments of the subframe local stiffness determination method of this application, and will not be repeated here.

[0058] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0059] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0060] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0061] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0062] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0063] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0064] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for determining the local stiffness of a subframe, characterized in that, The method for determining the local stiffness of the subframe includes: Obtain the KC characteristic design target of the target suspension and determine the overall stiffness design requirements of the suspension system; Construct a rigid body simulation model of the suspension, and determine the bushing stiffness parameters at each connection position of the suspension based on the KC characteristic design objective. Based on the overall stiffness design requirements and the bushing stiffness parameters, the initial target value of the local stiffness of the subframe is determined through the stiffness series equivalent relationship. Based on the initial target value of the subframe local stiffness, a suspension simulation model including the equivalent subframe stiffness is constructed. The final target value of the subframe local stiffness is corrected and locked through KC characteristic simulation verification.

2. The method for determining the local stiffness of the subframe as described in claim 1, characterized in that, The acquisition of the KC characteristic design target of the target suspension and the determination of the overall stiffness design requirements of the suspension system include: Based on the chassis handling performance requirements of the target vehicle, determine the design threshold range of the suspension KC characteristics; Based on the design threshold range of the KC characteristic, the total stiffness design requirements of the suspension system under the corresponding working conditions are determined. The total stiffness design requirements are the series total stiffness thresholds of the suspension system required to ensure that the KC characteristic meets the standards.

3. The method for determining the local stiffness of the subframe as described in claim 1, characterized in that, The construction of the suspension rigid body simulation model, based on the KC characteristic design objective, determines the bushing stiffness parameters at each connection position of the suspension, including: A rigid body simulation model of the suspension system is constructed, and the suspension linkage, steering knuckle, and subframe are all set as rigid body elements to shield the stiffness deformation effects of non-bushing components. With the goal of achieving the KC characteristic design objective as the optimization objective, the bushing stiffness parameters at each connection node of the suspension are adjusted and determined, and the bushing stiffness design value is locked.

4. The method for determining the local stiffness of the subframe as described in claim 1, characterized in that, The initial target value of the subframe local stiffness is determined based on the overall stiffness design requirements and the bushing stiffness parameters, through the stiffness series equivalent relationship, including: The local stiffness at the connection point between the subframe and the suspension rods is equivalent to an equivalent elastic element connected in series along the suspension force transmission path; Based on the force transmission path of the suspension system, the series stiffness relationship between the equivalent elastic element and the corresponding bushing is determined. To meet the overall stiffness design requirements, and in conjunction with the locked bushing stiffness parameters, the stiffness threshold of the equivalent elastic element is determined as the initial target value for the local stiffness of the subframe.

5. The method for determining the local stiffness of the subframe as described in claim 1, characterized in that, The suspension simulation model, which includes equivalent subframe stiffness, is constructed based on the initial target value of the subframe local stiffness, including: Based on the suspension rigid body simulation model, a rigid body transformation unit is added at the connection position between the suspension rod and the subframe; The suspension members are connected to the rigid body conversion unit through bushing units with locked stiffness at corresponding positions, and the rigid body conversion unit is connected to the subframe through equivalent elastic units representing the local stiffness of the subframe. The initial target value of the local stiffness of the subframe is assigned to the equivalent elastic element to complete the construction of the suspension simulation model including the stiffness of the equivalent subframe.

6. The method for determining the local stiffness of the subframe as described in claim 1, characterized in that, The process of verifying, correcting, and locking the final target value of the subframe local stiffness through KC characteristic simulation includes: Using the suspension simulation model that includes the equivalent subframe stiffness, perform KC characteristic simulation analysis under the target working condition to obtain the simulation KC characteristic results; The simulation KC characteristic results are compared with the preset KC characteristic design target to determine whether the design requirements are met. If the design requirements are not met, adjust the stiffness parameters of the equivalent elastic element and repeat the KC characteristic simulation analysis until the simulation KC characteristic results meet the design requirements. Then, lock the corresponding stiffness parameters as the final target value of the local stiffness of the subframe.

7. The method for determining the local stiffness of the subframe as described in claim 1, characterized in that, The subframe local stiffness includes multiple sets of local stiffness at the connection nodes between the subframe and each suspension member. For each suspension connection node of the subframe, the corresponding bushing stiffness parameter locking, equivalent elastic element stiffness calculation, and simulation verification correction steps are performed to determine the final target value of the local stiffness of the subframe corresponding to each connection node.

8. A device for determining the local stiffness of a subframe, characterized in that, The subframe local stiffness determination device includes: The target determination module is used to obtain the KC characteristic design target of the target suspension and determine the overall stiffness design requirements of the suspension system. The bushing stiffness calibration module is used to construct a suspension rigid body simulation model and determine the bushing stiffness parameters at each connection position of the suspension based on the KC characteristic design target. The stiffness target calculation module is used to determine the initial target value of the local stiffness of the subframe based on the total stiffness design requirements and the bushing stiffness parameters, through the stiffness series equivalent relationship. The simulation verification and locking module is used to construct a suspension simulation model containing equivalent subframe stiffness based on the initial target value of the subframe local stiffness, and to correct and lock the final target value of the subframe local stiffness through KC characteristic simulation verification.

9. A device for determining the local stiffness of a subframe, characterized in that, The subframe local stiffness determination device includes a processor, a memory, and a subframe local stiffness determination program stored in the memory and executable by the processor, wherein when the subframe local stiffness determination program is executed by the processor, it implements the steps of the subframe local stiffness determination method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a subframe local stiffness determination program, wherein when the subframe local stiffness determination program is executed by a processor, it implements the steps of the subframe local stiffness determination method as described in any one of claims 1 to 7.

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