Automobile chassis structural member parameter fitting optimization method and load acquisition method
By constructing a suspension vertical vibration model and optimization algorithm, and backfitting the parameters of chassis structural components, the problem of difficulty in obtaining loads in existing technologies is solved, achieving efficient and low-cost load calculation, and improving model accuracy and R&D efficiency.
Patent Information
- Application Number
- CN202511864940.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-02-27
AI Technical Summary
Existing technologies for obtaining loads on automotive chassis structural components, especially critical loads such as buffer block forces that are difficult to measure directly, suffer from problems such as measurement difficulties, high costs, reliance on experience, and low model accuracy, resulting in inaccurate simulation results and low R&D efficiency.
By constructing a vertical vibration model of the suspension and using measured time history data and optimization algorithms, the parameters of the chassis structural components, including the equivalent stiffness of the springs, the lever ratio, and the equivalent stiffness of the stabilizer bar, are backfitted to achieve automatic overall fitting of multiple key parameters and calculate loads such as the buffer block force.
It significantly improves parameter calibration efficiency and model accuracy, reduces testing difficulty and cost, enhances the construction efficiency of chassis dynamics models and the confidence of whole vehicle simulation, and achieves high-precision acquisition of loads such as buffer block force.
Smart Images
Figure CN121580677A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of vehicle engineering and testing technology, and in particular to a parameter fitting optimization method for a vehicle chassis structural component and a load acquisition method. BACKGROUND
[0002] Obtaining accurate road loads is the cornerstone of strength verification, fatigue analysis and performance optimization of automobile chassis structural components (such as steering knuckles, shock absorbers, bumpers, etc.) in the research and development stage. At present, the direct measurement method and the measurement simulation combined method are mainly used to obtain these loads in engineering practice. The direct measurement method can directly obtain the load time history of the target structural component by installing force or strain sensors on it, and the data is accurate and reliable, but it is difficult to apply to all structural components, especially components with narrow internal space or complex stress, such as bumpers, due to factors such as vehicle space layout, sensor installation feasibility, test cost and vehicle destructive modification. For loads that cannot be directly measured, the existing method generally adopts the method of combining measurement and simulation: the wheel shaft load is measured by sensors, and then the measured shaft load is input into the pre-established vehicle or chassis multi-body dynamics model, and the load of the target structural component is calculated by dynamics. This method can overcome the difficulty of direct measurement to some extent, but the accuracy of the calculation result is highly dependent on the accuracy of a large number of parameters in the model.
[0003] In order to obtain reliable simulation results, these parameters often need to be measured and calibrated through tedious special tests, or rely on the experience of engineers to repeatedly debug and modify the model. This process is time-consuming, labor-intensive and costly, and is highly dependent on individual experience, and the reusability and simulation efficiency of the model are low. For key loads such as bumper forces that are difficult to measure directly, the existing indirect calculation method is difficult to quickly and economically obtain satisfactory results due to the calibration accuracy and efficiency of the model parameters. This traditional parameter acquisition method is scattered and inefficient, which restricts the improvement of vehicle simulation confidence and research and development efficiency. SUMMARY
[0004] The purpose of the present application is to provide a parameter fitting optimization method for a vehicle chassis structural component and a load acquisition method to solve the above problems, which can quickly, automatically and integrally obtain the optimal fitting value of the parameters of the vehicle chassis structural component based on the measured data, and significantly improve the parameter calibration efficiency and model accuracy.
[0005] The present application provides a parameter fitting optimization method for a vehicle chassis structural component, comprising the following steps:
[0006] The measured time history data of the vehicle running is measured and obtained, and the measured time history data includes the measured time history of the shaft force F wheel(t), the time history of the first damper displacement d1(t);
[0007] constructing a vehicle suspension vertical vibration model in which a non-sprung mass is balanced in a vertical direction, the load on the non-sprung mass in the vertical direction being related to a parameter of a vehicle chassis structure;
[0008] calculating an axle head force prediction time history F wheel_predicted (t) based on measured time history data and the suspension vertical vibration model;
[0009] constructing a loss function based on a difference between the measured time history F wheel (t) of the axle head force and the prediction time history F wheel_predicted (t) of the axle head force;
[0010] iteratively solving the parameter of the vehicle chassis structure using an optimization algorithm to minimize the loss function, and obtaining an optimal fitting value of the parameter of the vehicle chassis structure.
[0011] In one embodiment, the load on the non-sprung mass in the vertical direction includes a spring force F spring (t), a damper force F damper (t), a bump block force F bumpstop (t), a stabilizer bar force F antiroll (t), an inertial force F acc (t), and an axle head force.
[0012] In one embodiment, the calculation formula of the axle head force prediction time history F wheel_predicted (t) is: .
[0013] In one embodiment,
[0014] The measured time history data further includes a time history of a second damper displacement d2(t);
[0015] The parameter of the vehicle chassis structure includes a spring equivalent stiffness k1, a lever ratio i, a stabilizer bar equivalent stiffness k2, an equivalent non-sprung mass m, and a gap distance Δ from the top of the damper to the bottom of the bump block.
[0016] The spring force F spring (t) = k1 x d1(t);
[0017] The damper force F damper (t) = i x f 减震器特性 (v(t));
[0018] The bump block force F bumpstop (t) = i x f 缓冲块特性 (d1(t) - Δ);
[0019] Stabilizer bar force F antiroll (t) = k2 x (d1(t) - d2(t));
[0020] Inertial force F acc (t) = m x a wheel (t);
[0021] Where v(t) is the time history of the first shock absorber velocity, which is calculated based on d1(t);
[0022] a wheel (t) is the time history of the axle head vertical acceleration, which is obtained by measurement or calculated based on v(t);
[0023] f 减震器特性 (v) is the function relationship between the shock absorber force and the shock absorber velocity, which is obtained by measurement or using design parameters;
[0024] f 缓冲块特性 (d) is the function relationship between the bump stop force and the bump stop displacement, which is obtained by measurement or using design parameters.
[0025] In one embodiment, the time history of the first shock absorber velocity v(t) is obtained by differentiating the time history of the first shock absorber displacement d1(t);
[0026] The time history of the axle head vertical acceleration a wheel (t) is obtained by differentiating the time history of the first shock absorber velocity v(t).
[0027] In one embodiment, an optimization algorithm is used to iteratively solve the parameters of the automobile chassis structural components, so as to minimize the loss function and obtain the optimal fitting value of the parameters of the automobile chassis structural components, which specifically includes:
[0028] Step S101, set the initial value of the automobile chassis structural component parameters according to the actual suspension structure, wherein the automobile chassis structural component parameters include the equivalent stiffness of the spring k1, the lever ratio i, the equivalent stiffness of the stabilizer bar k2, the equivalent un-sprung mass m, and the gap distance Δ between the top of the shock absorber and the bottom of the bump stop;
[0029] Step S102, calculate the time history of the axle head force F wheel_predicted (t) based on the value of the automobile chassis structural component parameters, and calculate the loss function value according to the measured time history of the axle head force F wheel (t);
[0030] Step S103, automatically generate new chassis structural component parameter values according to the loss function value and the rules of the optimization algorithm, and repeat step S102;
[0031] Step S104, the iteration process continues until a preset termination condition is met, and a set of automobile chassis structural member parameter values that minimizes the loss function value is selected from all iteration processes as the optimal fitting value output, the termination condition being that the loss function value is less than a set threshold or a preset maximum number of iterations is reached.
[0032] In one embodiment, the optimization algorithm is a global optimization algorithm.
[0033] In one embodiment, the loss function Loss is the mean square error between the shaft head force prediction time history and the shaft head force measured time history, and the calculation formula is: .
[0034] The application also provides an automobile chassis structural member load acquisition method, comprising the following steps:
[0035] The optimal fitting value of the automobile chassis structural member parameters is obtained by using the automobile chassis structural member parameter fitting optimization method described above.
[0036] Based on the time history d1(t) of the first shock absorber displacement, the time history d2(t) of the second shock absorber displacement, the time history a wheel (t) of the shaft head vertical acceleration, the functional relationship f 减震器特性 (v) of the shock absorber force and the shock absorber speed, and / or the functional relationship f 缓冲块特性 (d) of the bump stop force and the bump stop displacement, and the optimal fitting value of the automobile chassis structural member parameters, the automobile chassis structural member load is calculated.
[0037] In one embodiment, the chassis structural member parameters include at least one of the spring equivalent stiffness k1, the lever ratio i, the stabilizer bar equivalent stiffness k2, the equivalent un-sprung mass m, and the gap distance Δ from the top of the shock absorber to the bottom of the bump stop.
[0038] The chassis structural member load includes at least one of the spring force F spring (t), the shock absorber force F damper (t), the bump stop force F bumpstop (t), the stabilizer bar force F antiroll (t).
[0039] Compared with the prior art, the automobile chassis structural member parameter fitting optimization method and the load acquisition method of the application have the following beneficial effects:
[0040] 1) The present application provides a high-efficiency vehicle chassis system key parameter overall fitting method, by constructing a suspension vertical vibration model containing nonlinear component characteristics, and taking the measured axle head force as the target, using an optimization algorithm to automatically fit multiple key parameters at one time, quickly, automatically and integrally obtaining the optimal fitting value of the chassis structure parameter in the model, significantly improving the parameter calibration efficiency and model accuracy, greatly improving the construction efficiency and accuracy of the chassis dynamics model, providing more reliable input for vehicle dynamics simulation, significantly improving the confidence of the simulation model and the reuse efficiency of the research and development tool, accelerating product development iteration.
[0041] 2) The present application only needs to use easily measured axle head force and shock absorber displacement signals to directly and accurately calculate the time history of the bump stop force, realizes high-precision and low-cost acquisition of the key structure load, especially the bump stop force, which is difficult to directly measure, greatly reduces the test difficulty and cost while ensuring data accuracy. BRIEF DESCRIPTION OF DRAWINGS
[0042] Figure 1 The flowchart of the vehicle chassis structure parameter fitting optimization method of an embodiment of the present application;
[0043] Figure 2 The vehicle suspension vertical vibration model diagram of an embodiment of the present application;
[0044] Figure 3 The time history diagram of the first shock absorber displacement of an embodiment of the present application;
[0045] Figure 4 The time history diagram of the first shock absorber velocity of an embodiment of the present application;
[0046] Figure 5 The time history diagram of the axle head vertical acceleration of an embodiment of the present application;
[0047] Figure 6 The velocity-force characteristic curve diagram of the shock absorber of an embodiment of the present application;
[0048] Figure 7 The displacement-force characteristic curve diagram of the bump stop of an embodiment of the present application;
[0049] Figure 8 The comparison curve diagram of the time history of each load and the predicted and measured values of the axle head force after fitting the vehicle chassis structure parameters of an embodiment of the present application. DETAILED DESCRIPTION
[0050] In order to make the objectives, technical solutions and advantages of the present application more apparent, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that in the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in other different manners than those described herein, and those skilled in the art can make similar generalizations without departing from the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.
[0051] Secondly, "one embodiment" or "an embodiment" in the present application means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment", "an embodiment" appearing in different places in the specification do not all refer to the same embodiment, nor are they separate or alternative embodiments mutually exclusive with other embodiments. The words "include" and "contain" mean that the claimed features exist, but do not exclude the existence of one or more other features. The word "and / or" used in the present application includes any and all combinations of one or more of the related listed terms.
[0052] The present application proposes a parameter fitting optimization method for an automobile chassis structural member, referring to Figure 1 , comprising the following steps:
[0053] Step S1, measured time history data of vehicle running is measured and acquired, the measured time history data including an axle head force measured time history F wheel (t), a time history of the first shock absorber displacement d1(t).
[0054] Step S2, a vehicle suspension vertical vibration model is constructed, the load borne by the unsprung mass in the vertical direction is balanced in the suspension vertical vibration model, and the load borne by the unsprung mass in the vertical direction is related to the automobile chassis structural member parameters. Specifically, referring to Figure 2 , the suspension vertical vibration model is a two-degree-of-freedom vibration model, specifically including a sprung mass and an unsprung mass connected by parallel springs and dampers, the unsprung mass refers to structural members such as wheels and steering knuckles, and the sprung mass refers to structural members such as vehicle bodies. The unsprung mass is taken as the object of force analysis, and all loads (including inertial forces) borne by the unsprung mass in the vertical direction are balanced.
[0055] Step S3, an axle head force predicted time history F wheel_predicted (t) is calculated based on the measured time history data and the suspension vertical vibration model.
[0056] Step S4, a loss function is constructed based on the difference between the axle head force measured time history F wheel (t) and the predicted time history F wheel_predicted (t).
[0057] Step S5, using an optimization algorithm to iteratively solve the parameters of the automobile chassis structure, minimize the loss function, and obtain the optimal fitting value of the parameters of the automobile chassis structure as the parameters of the vehicle simulation.
[0058] The above method is mainly aimed at the vertical load of front and rear wheels, and can be applied to various suspension design forms, including Macpherson suspension, double wishbone suspension, multi-link suspension, torsion beam suspension, etc. The spring can be a traditional spring or an air spring. The shock absorber can be a traditional oil shock absorber or a variable damping shock absorber.
[0059] The load borne by the unsprung mass in the vertical direction in an embodiment of the present application includes spring force F spring (t), shock absorber force F damper (t), bump block force F bumpstop (t), stabilizer bar force F antiroll (t), inertia force F acc (t), and axle head force.
[0060] Based on the above force load conditions, the axle head force prediction time history F wheel_predicted (t) can be obtained, and the calculation formula is: That is, the axle head force prediction time history F wheel_predicted (t) is the algebraic sum of the time histories of the spring force F spring (t), the shock absorber force F damper (t), the bump block force F bumpstop (t), the stabilizer bar force F antiroll (t), the inertia force F acc (t).
[0061] The measured time history data of an embodiment of the present application also includes the time history d2(t) of the second shock absorber displacement, and the first shock absorber and the second shock absorber are respectively located on the left and right sides of the wheel. The automobile chassis structure parameters include spring equivalent stiffness k1, lever ratio i (the conversion ratio between the force at the shock absorber or bump block mounting point and the axle head vertical force, which is used as a proportional coefficient to convert the force obtained from the shock absorber / bump block characteristic curve into the contribution to the axle head vertical force), stabilizer bar equivalent stiffness k2, equivalent unsprung mass m (the total mass of all components in the suspension system that move vertically with the wheel is concentrated at the center of the wheel), and gap distance Δ (also known as free travel Δ) from the top of the shock absorber to the bottom of the bump block.
[0062] The calculation formula of each load borne by the unsprung mass in the vertical direction is: spring force F spring (t)=k1×d1(t); shock absorber force F damper (t)=i×f 减震器特性(v(t)); buffer block force F bumpstop (t) = i x f 缓冲块特性 (d1(t) - Δ); stabilizer bar force F antiroll (t) = k2 x (d1(t) - d2(t)); inertial force F acc (t) = m x a wheel (t). Wherein, v(t) is the time history of the first shock absorber speed, which is obtained based on d1(t); a wheel (t) is the time history of the vertical acceleration of the axle head, which is obtained by measurement or based on v(t); f 减震器特性 (v) is the function relationship between the shock absorber force and the shock absorber speed, which is obtained by measurement or using design parameters; f 缓冲块特性 (d) is the function relationship between the buffer block force and the buffer block displacement, which is obtained by measurement or using design parameters.
[0063] f 减震器特性 (v) is obtained by measurement in the following way: the shock absorber is installed on a dynamometer, and its piston rod is driven to reciprocate at a series of known and controllable speeds v, while a high-precision sensor measures the damping force F generated by it in real time, and the speed-force characteristic curve (function relationship) of the shock absorber can be obtained by curve fitting, see Figure 6 f 缓冲块特性 (d) is obtained by measurement in the following way: a material testing machine or a dedicated buffer block test bench is used to apply a quasi-static compression displacement d to the buffer block sample, and the corresponding counterforce F is measured, so as to obtain the displacement-force characteristic curve (function relationship) of the buffer block, see Figure 7 Directly using design parameters means directly using theoretical parameters or standard characteristic data that have been determined or given in the design stage of the components.
[0064] The time history v(t) of the first shock absorber speed of an embodiment of the present application is obtained by numerical differentiation based on the time history d1(t) of the first shock absorber displacement, specifically by first-order differentiation of the time history d1(t) of the first shock absorber displacement. The time history a wheel (t) of the vertical acceleration of the axle head is obtained by differentiation of the time history v(t) of the first shock absorber speed.
[0065] The step S5 of an embodiment of the present application uses an optimization algorithm to iteratively solve the parameters of the automobile chassis structural parts, so as to minimize the loss function and obtain the optimal fitting value of the parameters of the automobile chassis structural parts, which specifically includes:
[0066] Step S101, estimate the initial value of the automobile chassis structure parameter according to the actual suspension structure (such as the design drawing of the suspension system, the part manual data, etc.), the automobile chassis structure parameter includes the spring equivalent stiffness k1, the lever ratio i, the stabilizer bar equivalent stiffness k2, the equivalent non-spring mass m, the gap distance Δ of the shock absorber top to the buffer block bottom;
[0067] Step S102, based on the automobile chassis structure parameter value, combined with the obtained first shock absorber displacement time history d1(t), the second shock absorber displacement time history d2(t), the axle head vertical acceleration time history a wheel (t), the function relationship f 减震器特性 (v) of the shock absorber force and the shock absorber speed, the function relationship f 缓冲块特性 (d) of the buffer block force and the buffer block displacement, etc., calculate the axle head force prediction time history F wheel_predicted (t), and calculate the loss function value according to the obtained axle head force measured time history F wheel (t);
[0068] Step S103, according to the loss function value, combined with the rules of the optimization algorithm (such as selection, crossover, mutation and other operations), automatically generate new chassis structure parameter values, and repeat step S102;
[0069] Step S104, the iteration process continues until the preset termination condition is met, select a set of automobile chassis structure parameter values from all iteration processes to make the loss function value minimum as the optimal fitting value output, and the termination condition is that the loss function value is less than the set threshold or reaches the preset maximum iteration number.
[0070] Because the suspension vertical vibration model contains the nonlinear characteristic function of the shock absorber and the buffer block, and there is coupling between the to-be-optimized parameters, the loss function is a complex non-convex function, and there are multiple local minimum values. In order to reliably find the parameter set that globally minimizes the loss function and avoid the optimization process falling into a local optimal solution and causing fitting failure, the application preferably uses a global optimization algorithm for iterative solution. The global optimization algorithm is a kind of algorithm aiming at searching in the entire feasible parameter space to find the global optimal solution (or approximate global optimal solution) of the target function, adopts a population (group) search strategy, that is, multiple sets of parameters (called "individuals") are maintained at the same time, and the different regions of the solution space are explored through the information exchange and random disturbance between individuals, so as to effectively jump out of the local optimal trap and greatly increase the probability of finding the global optimal solution.
[0071] As a preferred embodiment, the global optimization algorithm is a differential evolution algorithm. The differential evolution algorithm is based on swarm intelligence, performs parallel search in the parameter space through mutation, crossover and selection operations, has relaxed requirements on the mathematical properties of the objective function (does not require gradient calculation), is not sensitive to initial parameter guess, and has strong global optimization ability, and is particularly suitable for solving such engineering parameter optimization problems with nonlinear and multiple extreme value characteristics. Of course, those skilled in the art can also select other types of global optimization algorithms according to actual conditions, such as particle swarm optimization algorithm, genetic algorithm, etc.
[0072] The loss function Loss of an embodiment of the application is the mean square error between the shaft head force prediction time history and the shaft head force measured time history, and the calculation formula is: .
[0073] The application further provides a vehicle chassis structural part load acquisition method, comprising the following steps:
[0074] The optimal fitting value of the vehicle chassis structural part parameters is obtained by using the vehicle chassis structural part parameter fitting optimization method described above, wherein the chassis structural part parameters include at least one of the spring equivalent stiffness k1, the lever ratio i, the stabilizer bar equivalent stiffness k2, the equivalent unsprung mass m, and the gap distance Δ from the top of the shock absorber to the bottom of the bump stop.
[0075] Based on the time history d1(t) of the first shock absorber displacement, the time history d2(t) of the second shock absorber displacement, the time history a wheel (t) of the shaft head vertical acceleration, the functional relationship f 减震器特性 (v) between the shock absorber force and the shock absorber speed, and / or the functional relationship f 缓冲块特性 (d) between the bump stop force and the bump stop displacement, and the optimal fitting value of the vehicle chassis structural part parameters, the vehicle chassis structural part load is calculated, wherein the chassis structural part load includes at least one of the spring force F spring (t), the shock absorber force F damper (t), the bump stop force F bumpstop (t), and the stabilizer bar force F antiroll (t).
[0076] The vehicle chassis structural part parameter fitting optimization method and the load acquisition method described above are described in detail below through specific operation steps, and the specific operation is as follows:
[0077] 1) Measure the shaft head force measured time history F wheel (t), the time history d1(t) of the first shock absorber displacement (see Figure 3 ) and the time history d2(t) of the second shock absorber displacement on the left and right sides of the vehicle wheel, respectively, during vehicle running;
[0078] 2) take the first and second derivative of the time history of the first shock absorber displacement d1(t) as the time history of the first shock absorber velocity v(t) (see Figure 4 ) and the time history of the axle head vertical acceleration a wheel (t) (see Figure 5 ), of course, a wheel (t) can also be obtained by measurement;
[0079] 3) obtain the shock absorber velocity-force characteristic curve f 减震器特性 (v) and the bump stop displacement-force characteristic curve f 缓冲块特性 (d) by measurement or directly using the design parameters, see Figure 6 、 Figure 7 , f 减震器特性 (v) is used to represent the nonlinear function relationship between the shock absorber force and the shock absorber velocity, if it is a variable damping shock absorber, then the corresponding damping relationship at each time should be used, f 缓冲块特性 (d) is used to represent the nonlinear function relationship between the bump stop force and the bump stop displacement;
[0080] 4) based on the above data and the parameters of the automobile chassis structure, calculate the time history of each load in the vertical direction on the unsprung mass in the vertical vibration model of the suspension, which is the spring force F spring (t), the shock absorber force F damper (t), the bump stop force F bumpstop (t), the stabilizer bar force F antiroll (t), and the inertial force F acc (t);
[0081] the spring force F spring (t) = k1 x d1(t);
[0082] the shock absorber force F damper (t) = i x f 减震器特性 (v(t));
[0083] the bump stop force F bumpstop (t) = i x f 缓冲块特性 (d1(t) - Δ);
[0084] the stabilizer bar force F antiroll (t) = k2 x (d1(t) - d2(t));
[0085] the inertial force F acc (t) = m x a wheel (t);
[0086] wherein k1 is the equivalent stiffness of the spring, i is the lever ratio, k2 is the equivalent stiffness of the stabilizer bar, m is the equivalent unsprung mass, and Δ is the gap distance from the top of the shock absorber to the bottom of the bump stop, also known as the free travel Δ.
[0087] 5) Calculate the time history of the vehicle vertical axle head force F based on the load balance of the unsprung mass in the vertical direction in the suspension vertical vibration model and the values of the loads mentioned above wheel_predicted (t): ;
[0088] 6) Use the mean square error between the time history of the axle head force and the measured time history of the axle head force as the loss function ;
[0089] 7) According to the actual suspension structure, estimate the initial values of the automobile chassis structure parameters including the equivalent spring stiffness k1, the lever ratio i, the equivalent stabilizer bar stiffness k2, the equivalent unsprung mass m, and the gap distance Delta from the top of the shock absorber to the bottom of the bump stop, and substitute them into the above formula to calculate the loss function, and then use the differential evolution algorithm to iteratively optimize the loss function, see Figure 8 , obtain a set of automobile chassis structure parameter values that minimize the loss function as the optimal fitting value output;
[0090] 8) Calculate the time history of the load of each component of the automobile chassis using the optimal fitting value of the automobile chassis structure parameters, such as the bump stop force F bumpstop (t) and the like.
[0091] It should be noted that in the present application, unless otherwise specified and limited, the term "connection" and the like should be understood broadly, for example, "connection" can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, or the internal connection of two elements, those skilled in the art can understand the specific meaning of the above-mentioned terms in the present application according to the specific circumstances. In addition, the terms "first", "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.
[0092] The present application has the following beneficial effects:
[0093] 1) The present application provides an efficient overall fitting method for key parameters of automobile chassis system, by constructing a suspension vertical vibration model containing nonlinear component characteristics, and taking the measured axle head force as the target, using optimization algorithm to automatically fit multiple key parameters at one time, quickly, automatically and integrally obtaining the optimal fitting value of the chassis structure parameters in the model, significantly improving the parameter calibration efficiency and model accuracy, greatly improving the construction efficiency and accuracy of the chassis dynamics model, providing more reliable input for vehicle dynamics simulation, significantly improving the confidence of the simulation model and the reuse efficiency of the research and development tool, accelerating product development iteration.
[0094] 2) The application only needs to utilize easily measured axle head force, shock absorber displacement and other signals to directly and accurately calculate the time history of the bumper block force, realizes high-precision and low-cost acquisition of the key structural member load, especially the bumper block force, which is difficult to directly measure, greatly reduces the test difficulty and cost while ensuring data precision.
[0095] Although the above-described methods are illustrated and described as a series of acts, it will be appreciated that the methods are not limited by the order of acts as per one or more embodiments, some acts can occur in different orders and / or concurrently with other acts from that shown and described herein, and / or in between other acts not shown or described herein. Furthermore, not all illustrated acts can be required to implement one or more embodiments of the methods.
[0096] The constructions and arrangements of the application shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in this application. For example, elements shown as integrally formed can be constructed of multiple parts or elements, the position of elements can be reversed or otherwise varied, and the nature or number of elements can be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the application. The order or sequence of any process or method steps can be varied or re-sequenced without materially affecting the application. Any "means plus function" clauses are intended to cover the structures described herein as performing the recited functions and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions, and / or parameters of the application without departing from the spirit of the application as expressed in the claims.
Claims
1. A method for fitting and optimizing parameters of automotive chassis structural components, characterized in that, Includes the following steps: The measured time history data of the vehicle's travel is obtained by measurement, including the measured time history of the axle head force F. wheel (t), the time history of the displacement of the first shock absorber d1(t); A vertical vibration model of a vehicle suspension is constructed. In the vertical vibration model of the suspension, the unsprung mass is subjected to balanced loads in the vertical direction. The loads on the unsprung mass in the vertical direction are related to the parameters of the vehicle chassis structural components. Based on measured time history data and a suspension vertical vibration model, the predicted time history of the axle head force F was calculated. wheel_predicted (t); The measured time history F of the shaft head force wheel (t) and predicted time history F wheel_predicted The difference between (t) is used to construct the loss function; An optimization algorithm is used to iteratively solve the parameters of the automotive chassis structural components, minimizing the loss function and obtaining the optimal fitting values of the automotive chassis structural component parameters.
2. The method for fitting and optimizing parameters of automotive chassis structural components according to claim 1, characterized in that, The load on the unsprung mass in the vertical direction includes the spring force F. spring (t), shock absorber force F damper (t), buffer block force F bumpstop (t), stabilizer bar force F antiroll (t), inertial force F acc (t) and shaft head force.
3. The method for fitting and optimizing parameters of automotive chassis structural components according to claim 2, characterized in that, Shaft head force prediction time history F wheel_predicted The formula for calculating (t) is: .
4. The method for fitting and optimizing parameters of automotive chassis structural components according to claim 3, characterized in that, The measured time history data also includes the time history d2(t) of the displacement of the second shock absorber; The parameters of the automotive chassis structural components include the equivalent stiffness of the spring k1, the lever ratio i, the equivalent stiffness of the stabilizer bar k2, the equivalent unsprung mass m, and the clearance distance Δ from the top of the shock absorber to the bottom of the buffer block. Spring force F spring (t)=k1×d1(t); Shock absorber force F damper (t)=i×f 减震器特性 (v(t)); Buffer force F bumpstop (t)=i×f 缓冲块特性 (d1(t)-Δ); stabilizer bar force F antiroll (t)=k2×(d1(t)-d2(t)); Inertial force F acc (t)=m×a wheel (t); Where v(t) is the time history of the speed of the first shock absorber, which is obtained based on d1(t); a wheel (t) is the time history of the vertical acceleration of the shaft head, which is obtained through actual measurement or based on v(t); f 减震器特性 (v) represents the functional relationship between the shock absorber force and the shock absorber speed, obtained through actual measurement or by using design parameters; f 缓冲块特性 (d) represents the functional relationship between the buffer block force and the buffer block displacement, obtained through actual measurement or by using design parameters.
5. The method for fitting and optimizing parameters of automotive chassis structural components according to claim 4, characterized in that, The time history v(t) of the first shock absorber velocity is obtained by differentiating the time history d1(t) of the first shock absorber displacement. Time history of vertical acceleration at the shaft head a wheel (t) is obtained by differentiating the time history v(t) of the first shock absorber speed.
6. The method for fitting and optimizing parameters of automotive chassis structural components according to claim 4, characterized in that, An optimization algorithm is used to iteratively solve for the parameters of automotive chassis structural components, minimizing the loss function and obtaining the optimal fitted values for the parameters. Specifically, this includes: Step S101: Set the initial values of the vehicle chassis structural component parameters according to the actual suspension structure. The vehicle chassis structural component parameters include the spring equivalent stiffness k1, lever ratio i, stabilizer bar equivalent stiffness k2, equivalent unsprung mass m, and the gap distance Δ from the top of the shock absorber to the bottom of the buffer block. Step S102: Calculate the prediction time history F of axle head force based on the parameter values of automotive chassis structural components. wheel_predicted (t), and based on the obtained measured time history F of the shaft head force. wheel (t) Calculate the loss function value; Step S103: Based on the loss function value and the rules of the optimization algorithm, automatically generate new chassis structural component parameter values, and repeat step S102. Step S104: The iteration process continues until a preset termination condition is met. From all iterations, the set of automotive chassis structural component parameter values that minimize the loss function value is selected as the optimal fitting value and output. The termination condition is that the loss function value is less than a set threshold or the preset maximum number of iterations is reached.
7. The method for fitting and optimizing parameters of automotive chassis structural components according to claim 1, characterized in that, The optimization algorithm is a global optimization algorithm.
8. The method for fitting and optimizing parameters of automotive chassis structural components according to claim 1, characterized in that, The loss function, Loss, is the mean square error between the predicted time history of the shaft head force and the measured time history of the shaft head force. The calculation formula is as follows: .
9. A method for obtaining the load of an automotive chassis structural component, characterized in that, Includes the following steps: The optimal fitting value of the parameters of the automotive chassis structural components is obtained by using the parameter fitting optimization method of any one of claims 1-8. Based on the time history d1(t) of the displacement of the first shock absorber, the time history d2(t) of the displacement of the second shock absorber, and the time history a of the vertical acceleration of the axle head during vehicle operation. wheel (t) Functional relationship between shock absorber force and shock absorber speed f 减震器特性 (v) and / or the functional relationship between the buffer block force and the buffer block displacement f 缓冲块特性 (d) and the optimal fitting values of the parameters of the automotive chassis structural components are used to calculate the load of the automotive chassis structural components.
10. The method for obtaining the load of an automobile chassis structural component according to claim 9, characterized in that, The chassis structural parameters include at least one of the following: spring equivalent stiffness k1, lever ratio i, stabilizer bar equivalent stiffness k2, equivalent unsprung mass m, and gap distance Δ from the top of the shock absorber to the bottom of the buffer block. The load on the chassis structural components includes the spring force F. spring (t), shock absorber force F damper (t), buffer block force F bumpstop (t), stabilizer bar force F antiroll At least one of (t).