Dry brake pedal simulator stiffness modeling simulation method, system and product

Abstract

The invention provides a rigidity modeling simulation method, system and product for a dry brake pedal simulator, and relates to the technical field of automobile simulation. According to the method, a complete mechanical model comprising a pedal arm, a pedal support, a spring assembly, a friction assembly and limiting rubber is constructed in AMESim software; accurate simulation of the real working process of the dry brake pedal simulator is realized. According to the method, based on a pedal structure and a force transmission principle, pedal force is decoupled into three contributions of spring force of a spring assembly, rotating friction torque of a friction assembly and rubber force of limiting rubber after lever conversion, and synthetic calculation is performed through a torque balance principle, so that nonlinear characteristics of pedal rigidity can be truly reflected. By generating the pedal force-stroke relation curve and comparing the pedal force-stroke relation curve with the target rigidity curve, the key parameters can be rapidly iteratively optimized, the simulation precision and development efficiency of the design of the dry brake pedal simulator are improved, and the problems that in traditional empirical design, parameter matching is difficult, and the adjustment period is long are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile simulation technology, and particularly relates to a dry brake pedal simulator stiffness modeling simulation method, system and product. BACKGROUND

[0002] With the rapid development of new energy vehicles, the brake-by-wire system is gradually popularized. In the brake-by-wire system, the driver's braking intention is identified through brake pedal stroke or master cylinder pressure signals, and the brake pedal needs to provide reasonable force feedback through the internal spring and damping components to simulate the brake pedal feel of traditional fuel vehicles. Among them, the stiffness characteristics of the brake pedal are the key factors affecting the driving experience, and the performance is jointly affected by factors such as pedal hard point arrangement, spring parameters and shaft friction. At present, parameter matching mainly depends on experience design and repeated debugging, and the development efficiency is low. In addition, the existing technology is mainly applicable to pedal systems with hydraulic buffer structure, and cannot be applied to dry brake pedals with simpler structure and lower maintenance cost. SUMMARY

[0003] The present application aims to solve the technical problems in the above related technology, and proposes a dry brake pedal simulator stiffness modeling simulation method, system and product, which can accurately establish the mechanical model of the dry brake pedal, realize high-precision simulation and parameter matching of the pedal stiffness characteristics, and effectively improve the development efficiency and driving comfort of the dry brake-by-wire pedal.

[0004] The solution to the technical problem of the present application is: the present application provides a dry brake pedal simulator stiffness modeling simulation method, comprising the following steps: In the AMESim software, according to the mechanical structure of the dry brake pedal simulator, a brake pedal stiffness simulation model including a pedal arm, a pedal support, a spring assembly, a friction assembly and a limiting rubber is built; According to the structure and working principle of the brake pedal, the key parameters affecting the stiffness of the brake pedal are determined and set in the brake pedal stiffness simulation model; the key parameters are used to simulate the spring force characteristics of the spring assembly, the rotational friction torque characteristics of the friction assembly and the rubber force characteristics of the limiting rubber; Based on the torque balance principle, the contribution of the spring force generated by the spring assembly to the pedal force after lever conversion is calculated as the first contribution degree, the contribution of the rotational friction torque generated by the friction assembly to the pedal force after lever conversion is calculated as the second contribution degree, and the contribution of the rubber force generated by the limiting rubber to the pedal force after lever conversion is calculated as the third contribution degree; According to the first contribution degree, the second contribution degree and the third contribution degree, the brake pedal force is calculated, the relationship curve between the brake pedal force and the pedal stroke is generated, and the key parameters are adjusted so that the relationship curve fits the target pedal stiffness curve.

[0005] Further, the key parameters include: the pedal point coordinate of the brake pedal, the pivot point coordinate of the pedal arm, the initial position limit point coordinate of the pedal arm, the initial position coordinate of the contact point between the pedal arm and the center point of the limit rubber, the limit position coordinate of the contact point between the pedal arm and the center point of the limit rubber, the hinge point coordinate of the spring assembly and the pedal arm, the hinge point coordinate of the spring assembly and the friction assembly, the hinge point coordinate of the friction assembly and the pedal support, the upper surface geometric center point coordinate of the friction material in the friction assembly at the initial position of the friction assembly, the thickness of the friction material in the friction assembly, the stiffness of the friction material in the friction assembly, the friction coefficient of the friction material in the friction assembly and the pedal arm pivot, the pedal arm pivot radius, the pre-tightening force of the first spring in the spring assembly, the stiffness of the first spring in the spring assembly, the maximum compression stroke of the first spring in the spring assembly, the pre-tightening force of the second spring in the spring assembly, the stiffness of the second spring in the spring assembly, the maximum compression stroke of the second spring in the spring assembly, the limit rubber length, and the limit rubber stiffness.

[0006] Further, the stiffness of the first spring is less than the stiffness of the second spring, and the maximum compression stroke of the first spring is less than the maximum compression stroke of the second spring, the parameters of the first spring are set to simulate the initial segment characteristics of the brake pedal stiffness curve, and the parameters of the second spring are set to simulate the middle and rear segment characteristics of the brake pedal stiffness curve.

[0007] Further, the calculation method of the rotational friction torque is: according to the spring force of the spring assembly on the friction assembly, the hinge point coordinate of the spring assembly and the friction assembly, the hinge point coordinate of the spring assembly and the pedal arm, the hinge point coordinate of the friction assembly and the pedal support, the upper surface geometric center point coordinate of the friction material in the friction assembly at the initial position of the friction assembly, the thickness of the friction material in the friction assembly, and the stiffness of the friction material in the friction assembly, the normal pressure of the friction assembly on the pedal arm pivot is calculated, then according to the friction coefficient of the friction material in the friction assembly and the pedal arm pivot, the friction force is calculated, and finally the friction force is multiplied by the pedal arm pivot radius to obtain the rotational friction torque.

[0008] Further, the limit rubber stiffness, the initial position coordinate of the contact point between the pedal arm and the center point of the limit rubber, and the limit position coordinate of the contact point between the pedal arm and the center point of the limit rubber are set to simulate the rear segment characteristics of the brake pedal stiffness curve.

[0009] Further, the adjusted key parameters include at least one of the hinge point coordinate of the spring assembly and the pedal arm, the hinge point coordinate of the spring assembly and the friction assembly, the hinge point coordinate of the friction assembly and the pedal support, and the initial position coordinate of the contact point between the pedal arm and the center point of the limit rubber, to change the force transmission leverage ratio.

[0010] Further, the target pedal stiffness curve is a three-segment curve, including: First segment, pedal stroke is 0 to 21mm, the first spring and the second spring are compressed together, while the rotational friction torque is superimposed, the pedal force increases approximately linearly with the pedal stroke; Second segment, pedal stroke is 21mm to 58mm, the first spring reaches the maximum compression stroke, the second spring continues to compress, while the rotational friction torque is superimposed, the pedal force increases linearly with the pedal stroke, the slope decreases; Third segment, pedal stroke > 58mm, the second spring continues to compress, the pedal arm compresses the limiting rubber, while the rotational friction torque is superimposed, the pedal force increases linearly with the pedal stroke, the slope further decreases.

[0011] In another aspect, the application provides a dry brake pedal simulator stiffness modeling and simulation system, comprising the following modules: A model building module is used to build a brake pedal stiffness simulation model including a pedal arm, a pedal support, a spring assembly, a friction assembly and a limiting rubber in the AMESim software according to the mechanical structure of the dry brake pedal simulator; A parameter input module is used to determine the key parameters affecting the brake pedal stiffness according to the structure and working principle of the brake pedal, and set them in the brake pedal stiffness simulation model; the key parameters are used to simulate the spring force characteristics of the spring assembly, the rotational friction torque characteristics of the friction assembly and the rubber force characteristics of the limiting rubber; A force calculation module is used to calculate the contribution of the spring force generated by the spring assembly to the pedal force after lever conversion as the first contribution degree, the contribution of the rotational friction torque generated by the friction assembly to the pedal force after lever conversion as the second contribution degree, and the contribution of the rubber force generated by the limiting rubber to the pedal force after lever conversion as the third contribution degree based on the torque balance principle; A parameter optimization module is used to calculate the brake pedal force according to the first contribution degree, the second contribution degree and the third contribution degree, generate a relationship curve between the brake pedal force and the pedal stroke, and adjust the key parameters so that the relationship curve fits the target pedal stiffness curve.

[0012] Further, the system provides a graphical interactive interface, the interactive interface is used to realize parameter setting, effect preview and report generation; the interactive interface includes a parameter input unit, a stiffness curve visualization unit and a simulation report output unit; In the parameter input unit, the user sets the key parameters of the brake pedal through an input box or a drop-down menu, including: the coordinates of the pedal point of the brake pedal, the coordinates of the pivot point of the pedal arm, the coordinates of the initial position limit point of the pedal arm, the coordinates of the initial position of the contact point between the pedal arm and the center point of the limiting rubber, the coordinates of the limit position of the contact point between the pedal arm and the center point of the limiting rubber, the coordinates of the hinge point between the spring assembly and the pedal arm, the coordinates of the hinge point between the spring assembly and the friction assembly, the coordinates of the hinge point between the friction assembly and the pedal support, the coordinates of the geometric center point of the upper surface of the friction material in the friction assembly at the initial position of the friction assembly, the thickness of the friction material in the friction assembly, the stiffness of the friction material in the friction assembly, the friction coefficient between the friction material in the friction assembly and the pedal arm pivot, the radius of the pedal arm pivot, the pre-tightening force of the first spring in the spring assembly, the stiffness of the first spring in the spring assembly, the maximum compression stroke of the first spring in the spring assembly, the pre-tightening force of the second spring in the spring assembly, the stiffness of the second spring in the spring assembly, the maximum compression stroke of the second spring in the spring assembly, the length of the limiting rubber, and the stiffness of the limiting rubber. In the stiffness curve visualization unit, a relationship curve between brake pedal force and pedal stroke is generated and displayed in real time, the relationship curve includes the segmented characteristics of the first segment, the second segment and the third segment, and the corresponding pedal stroke interval and force value range of each stage are labeled, for intuitive preview of the stiffness characteristics of the dry brake pedal simulator. In the simulation report output unit, an analysis report in multiple formats is automatically generated, including a list of set key parameters, a simulation stiffness curve image, a curve fitting error analysis, and suggestions for adjusting key parameters, the fitting error analysis includes the maximum deviation value and the average deviation rate of the simulation curve and the target stiffness curve, and the parameter adjustment suggestions are generated based on the sensitivity analysis of each parameter on the stiffness curve.

[0013] In another aspect, the application provides a computer program product comprising a computer program which, when executed by a processor, implements the dry brake pedal simulator stiffness modeling simulation method described above.

[0014] The application provides a dry brake pedal simulator rigidity modeling simulation method, which realizes accurate simulation of a real working process of the dry brake pedal simulator by constructing a complete mechanical model comprising a pedal arm, a pedal support, a spring assembly, a friction assembly and a limiting rubber in AMESim software.

[0015] Other features and advantages of the present application will be set forth in the following description, and in part will be apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of the technical scheme of the present application, and constitute a part of the specification, and are used together with the embodiments of the present application to explain the technical scheme of the present application, and do not constitute a limitation on the technical scheme of the present application.

[0017] Figure 1 is a flow chart of the dry brake pedal simulator rigidity modeling simulation method provided by the present application; Figure 2 is a brake pedal rigidity simulation curve schematic diagram provided by the present application; Figure 3 is a structure diagram of the dry brake pedal simulator rigidity modeling simulation system provided by the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the present application.

[0019] The application will be further described below in conjunction with the accompanying drawings and specific embodiments. The described embodiments should not be regarded as limiting the application, and all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0020] In the following description, "some embodiments" are related to a subset of all possible embodiments, but it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application is for the purpose of describing the embodiments of the application only and is not intended to be limiting of the application.

[0022] With the rapid development of new energy vehicles and intelligent driving technology, the traditional hydraulic brake system is gradually evolving towards electronic and intelligent brake-by-wire (BBW) system. In the brake-by-wire system, the driver's action of stepping on the brake pedal is no longer directly transmitted through the hydraulic pipeline to generate braking force, but the pedal stroke or angle signal is collected by the sensor, and the electronic control unit (ECU) identifies the driving intention, and calculates the target braking force in combination with the vehicle state, and finally realizes the wheel braking through the motor brake actuator. Since the mechanical connection and vacuum booster are cancelled, the driver can no longer feel the real "brake feedback" through the traditional way, so a special pedal feel simulation device must be designed on the brake pedal assembly to provide force feedback characteristics in line with ergonomics, to ensure that the driver obtains stable and predictable brake foot feel.

[0023] The current mainstream pedal feel simulation scheme mainly falls into two categories: wet pedal simulator and dry pedal simulator. The wet scheme usually adopts a small accumulator cooperating with a solenoid valve to generate damping and rebound force by using the pressure change of hydraulic oil; while the dry scheme completely relies on mechanical structures such as springs, rubber bumpers, friction components, etc. to realize force feedback without liquid medium. Compared with the wet scheme, the dry brake pedal has the advantages of simple structure, low cost, maintenance-free, strong environmental adaptability, etc., and is particularly suitable for new energy vehicles with high reliability requirements and lightweight pursuit, so its application is becoming more and more widespread.

[0024] However, the performance of dry brake pedal is highly dependent on the accurate matching of its internal mechanical parameters. The ideal pedal stiffness curve should have a reasonable initial force, a moderate growth slope, and sufficient travel reserve, both to avoid "soft" leading to insufficient braking confidence, and to prevent "hard" affecting comfort. This stiffness characteristic is mainly determined by the following factors: first, the spatial geometric arrangement of the pedal arm hinge points (i.e. "hard points"), which determines the lever ratio of force transmission; second, the pre-tightening force, stiffness and compression stroke of the pedal spring assembly, which directly affects the spring force output; third, the rotational friction torque existing at the pedal shaft, especially in structures with hysteresis friction design, the friction will change dynamically with the compression process, further affecting the overall pedal force. These factors are coupled with each other, making the pedal force-displacement relationship show complex nonlinear characteristics.

[0025] In view of the above problems, existing research attempts to assist pedal design through modeling and simulation. For example, patent CN117910126A discloses a pedal feel simulator modeling and simulation method based on the Amesim platform, which builds a system model including hydraulic elements, spring dampers and mechanical links, and can simulate and analyze the dynamic response of wet pedal simulator. Although this technology improves the development efficiency of wet systems to some extent, it is highly dependent on the modeling of hydraulic circuits, focusing on the calculation of fluid pressure and flow, which is not applicable to dry pedals dominated by pure mechanical structures.

[0026] In addition, the common practice in the industry is still to make preliminary design based on empirical formulas or static mechanics analysis, and then adjust parameters such as spring stiffness and installation position through multiple rounds of physical prototype testing. This method has obvious defects: first, physical prototype manufacturing has a long cycle and high cost, especially in the early stages of product development, frequent modifications of the structure are extremely inconvenient; second, traditional static calculations cannot accurately reflect the dynamic interaction between components during motion, especially the nonlinear behavior of friction changing with contact state; third, when multiple parameters (such as hard point coordinates, spring parameters, friction coefficients, etc.) simultaneously affect the output results, there is a lack of effective decoupling analysis tools, resulting in a blind and inefficient parameter tuning process, which often can only be optimized in a "trial and error" manner, making it difficult to quickly converge to the optimal solution.

[0027] More importantly, existing technologies generally ignore the mechanism of "hysteresis friction components" in dry brake pedals. In actual structures, some dry brake pedal designs have special friction mechanisms (such as swing arm assemblies with rubber bushings), which exert a positive pressure on the rotating shaft and generate a rotational friction torque that changes with displacement during compression. This friction torque, after being amplified by the lever, also contributes to the pedal force. If this item is ignored in simulation, the simulation results will deviate significantly from the actual test data, especially in the middle and later stages of travel, resulting in a loss of guidance.

[0028] In summary, current technological advancements lack a systematic modeling and simulation method specifically designed for dry brake pedals that comprehensively considers the geometric relationships of the mechanical structure, the nonlinear characteristics of the springs, and the dynamic friction effects. Existing simulation technologies are mostly focused on wet systems and cannot be transferred to dry structures; while traditional design methods rely too heavily on experience and experimentation, lacking theoretical support and rapid iteration capabilities. Therefore, there is an urgent need for a simulation method that can accurately reproduce the mechanical behavior of dry brake pedals in a virtual environment, achieving closed-loop optimization from parameter input to stiffness curve output. This would shorten the development cycle, reduce R&D costs, and improve the consistency of the pedal feel and the user experience of the final product.

[0029] To address the aforementioned issues, this application proposes a stiffness modeling and simulation method, system, and program product for a dry brake pedal simulator. Its core lies in constructing a complete mechanical system model based on the AMESim software platform, encompassing the pedal arm, bracket, spring assembly, friction assembly, and limiting rubber. This model comprehensively considers the combined effects of spring force, rotational friction torque, and the nonlinear stiffness of the limiting rubber on the pedal force. Based on the torque balance principle, this method decouples the mechanical contributions of each physical component into first, second, and third contributions to the pedal force, achieving high-precision simulation of the brake pedal force versus stroke curve. By adjusting key hard point coordinates, spring parameters, friction and rubber properties, the simulation curve quickly matches the preset target stiffness curve, thus providing an efficient, repeatable, and visualized simulation solution for the forward design and parameter optimization of dry brake pedals.

[0030] First, the stiffness modeling and simulation method for a dry brake pedal simulator provided in this application will be described in detail below with reference to the accompanying drawings.

[0031] Reference Figure 1 The implementation process of the dry brake pedal simulator stiffness modeling and simulation method provided in this application includes, but is not limited to, the following steps.

[0032] Step S110: In AMESim software, based on the mechanical structure of the dry brake pedal simulator, build a brake pedal stiffness simulation model including pedal arm, pedal bracket, spring assembly, friction assembly and limiting rubber.

[0033] It should be noted that AMESim is a professional multi-domain system simulation platform capable of modeling and dynamically analyzing complex engineering systems such as mechanical, hydraulic, electrical, and control systems. AMESim software provides an integrated virtual experimental environment, enabling engineers to predict and optimize system performance early in the product design process, significantly shortening development cycles, reducing R&D costs, and improving the scientific rigor and reliability of designs.

[0034] In step S110, a digital physical model corresponding to the actual dry brake pedal simulator structure is constructed. Using the AMESim software environment, based on the mechanical connections and motion constraints of the pedal system, a simulation model is established including key components such as the pedal arm, pedal support, spring assembly, friction assembly, and limiting rubber. This ensures that the connection methods, degrees of freedom of motion, and interaction relationships between the components accurately reflect the actual physical structure. This model provides a foundational platform for subsequent mechanical analysis, enabling the accurate reproduction of the pedal's kinematic and dynamic behavior during pedal application. It is the prerequisite and basis for achieving the entire stiffness simulation process.

[0035] Step S120: Based on the structure and working principle of the brake pedal, determine the key parameters affecting the stiffness of the brake pedal and set them in the brake pedal stiffness simulation model.

[0036] Key parameters are used to simulate the spring force characteristics of the spring assembly, the rotational friction torque characteristics of the friction assembly, and the rubber force characteristics of the limiting rubber.

[0037] In step S120, key design variables and material properties of the actual physical system are parameterized and input into the simulation model. These parameters include geometric hardpoint coordinates, spring preload and stiffness, friction material properties, and rubber stiffness. They directly determine the elastic response of the spring assembly during compression, the resistance torque generated by the friction assembly during rotation, and the nonlinear support force (i.e., rubber force) provided by the limiting rubber when compressed. By accurately setting these parameters in the model, the mechanical behavior of each component under different pedal strokes can be realistically reproduced, thus providing accurate input for subsequent calculations of pedal force synthesis.

[0038] Step S130: Based on the principle of torque balance, the contribution of the spring force generated by the spring assembly to the pedal force after lever conversion is calculated as the first contribution, the contribution of the rotational friction torque generated by the friction assembly to the pedal force after lever conversion is calculated as the second contribution, and the contribution of the rubber force generated by the limiting rubber to the pedal force after lever conversion is calculated as the third contribution.

[0039] In step S130, multiple mechanical sources in the pedal system are decoupled and analyzed, and their independent contributions to the final pedal force are quantified. Using the lever principle and torque balance, the forces and torques acting at different positions on the pedal arm (such as spring tension and compression, rotational friction torque, and restraint rubber reaction force) are converted to the pedal application point (usually the driver's pressing position) according to their lever arm relationships, thus obtaining three independent "contributions." This decomposition method not only reveals the influence mechanism of each component on the pedal stiffness but also provides a clear physical basis for subsequent parameter adjustments, ensuring that the simulation results have clear engineering interpretability.

[0040] Step S140: Calculate the brake pedal force based on the first contribution, the second contribution, and the third contribution, generate the relationship curve between the brake pedal force and the pedal stroke, and adjust the key parameters so that the relationship curve fits the preset target pedal stiffness curve.

[0041] In step S140, the process of integrating and verifying the contributions of individual mechanical components to the overall pedal stiffness characteristics is completed. By superimposing the three contributions calculated in the first three steps, the total pedal force under different pedal strokes is obtained, and a complete pedal force-stroke (FS) relationship curve, i.e., the pedal stiffness curve, is plotted. This curve intuitively reflects the pedal's stiffness characteristics, linearity, and stage variation trend. By comparing this simulation curve with the pre-set target stiffness curve, the matching degree of the current parameter configuration can be evaluated, and key parameters in the model (such as spring stiffness, hard point location, etc.) can be adjusted accordingly to achieve rapid iterative optimization of pedal stiffness and ultimately achieve the design goal.

[0042] In some embodiments of this application, key parameters include: the pedal tread coordinates, the pedal arm pivot point coordinates, the initial position limit point coordinates of the pedal arm, the initial position coordinates of the contact point between the pedal arm and the center point of the limiting rubber, the extreme position coordinates of the contact point between the pedal arm and the center point of the limiting rubber, the hinge point coordinates of the spring assembly and the pedal arm, the hinge point coordinates of the spring assembly and the friction assembly, the hinge point coordinates of the friction assembly and the pedal bracket, the geometric center point coordinates of the upper surface of the friction material in the friction assembly at the initial position of the friction assembly, the thickness of the friction material in the friction assembly, the stiffness of the friction material in the friction assembly, the coefficient of friction between the friction material in the friction assembly and the pedal arm pivot, the pedal arm pivot radius, the preload of the first spring in the spring assembly, the stiffness of the first spring in the spring assembly, the maximum compression stroke of the first spring in the spring assembly, the preload of the second spring in the spring assembly, the stiffness of the second spring in the spring assembly, the maximum compression stroke of the second spring in the spring assembly, the length of the limiting rubber, and the stiffness of the limiting rubber.

[0043] Specifically, the determined key parameters comprehensively cover the geometric, material, and mechanical properties that affect the stiffness characteristics of the dry brake pedal simulator. These parameters collectively determine the force-stroke response behavior of the pedal during pedaling. The coordinates of the pedal point, the pedal arm pivot point, each hinge point, and the initial and extreme position coordinates of the limit point collectively define the kinematic structure and force transmission path of the entire pedal mechanism, directly affecting the leverage ratio and the relative motion relationship of each component. Parameters such as the thickness, stiffness, friction coefficient with the pedal arm pivot, and the radius of the pedal arm pivot in the friction assembly are used to accurately model the normal pressure applied to the pivot by the friction assembly during compression and the resulting rotational friction torque. The preload, stiffness, and maximum compression stroke of the first and second springs in the spring assembly control the elastic response of the initial and later stages of the pedal stiffness curve, respectively, to achieve phased force growth characteristics. The length and stiffness of the limit rubber determine the nonlinear stiffness performance after the rubber intervenes in compression during the large stroke stage. By precisely setting these parameters in the simulation model, the generation mechanisms of spring force, friction torque, and limit support force can be realistically reproduced, providing a complete physical basis for subsequent calculation of the component contributions of pedal force and fitting of the overall stiffness curve, ensuring that the simulation results have high accuracy and engineering adjustability.

[0044] In some embodiments of this application, the stiffness of the first spring is less than that of the second spring, and the maximum compression stroke of the first spring is less than that of the second spring. The parameters of the first spring are set to simulate the initial characteristics of the brake pedal stiffness curve, and the parameters of the second spring are set to simulate the middle and later characteristics of the brake pedal stiffness curve.

[0045] Specifically, by designing two springs with different mechanical properties to work together, a precise simulation of the segmented characteristics of the brake pedal stiffness curve is achieved. The first spring has lower stiffness and a shorter maximum compression stroke, allowing it to be the first to receive force and compress smoothly at the initial stage of pedal depressing, thus dominating the slow rise of pedal force in the initial stage and providing a soft, linear initial feel. The second spring has higher stiffness but a longer compression stroke. At this point, the combined effect of the two springs increases the slope of the pedal force increase, simulating the "gradually increasing" feedback during the braking force build-up phase. Through this nonlinear superposition design of dual springs, a natural transition from "soft" to "hard" stiffness curve can be achieved in a single mechanism, more realistically restoring the segmented characteristics of the ideal pedal feel and improving the driving experience.

[0046] In some embodiments of this application, the rotational friction torque is calculated as follows: the normal force of the spring assembly on the friction assembly, the coordinates of the hinge point between the spring assembly and the friction assembly, the coordinates of the hinge point between the spring assembly and the pedal arm, the coordinates of the hinge point between the friction assembly and the pedal bracket, the coordinates of the geometric center point of the upper surface of the friction material in the friction assembly at the initial position of the friction assembly, the thickness of the friction material in the friction assembly, and the stiffness of the friction material in the friction assembly are used to calculate the normal force of the friction assembly on the pedal arm shaft. Then, the friction force is calculated based on the friction coefficient between the friction material in the friction assembly and the pedal arm shaft. Finally, the rotational friction torque is obtained by multiplying the friction force by the radius of the pedal arm shaft.

[0047] Specifically, the method for calculating rotational friction torque accurately reconstructs the resistance torque generated by the friction assembly on the pedal arm shaft during operation through systematic mechanical analysis. This method first determines the force transmission path and lever relationship based on the spring force applied to the friction assembly by the spring assembly, combined with the coordinates of the hinge points between the spring assembly and the pedal arm, the friction assembly, and the pedal support, thus analyzing the force state of the friction assembly during movement. Simultaneously, using the coordinates of the geometric center point of the friction material's upper surface, material thickness, and material stiffness at the initial position of the friction assembly, the normal force exerted by the friction assembly on the pedal arm shaft during compression is calculated. Based on this, the normal force is converted into tangential friction force according to the friction coefficient between the friction material and the shaft. Finally, this friction force is multiplied by the radius of the pedal arm shaft to obtain the rotational friction torque acting on the shaft. This calculation method fully considers the influence of structural geometry, material elasticity, and frictional characteristics on the friction torque, achieving high-precision modeling of the rotational friction effect and providing a reliable theoretical basis for accurately assessing its secondary contribution to the total force of the pedal.

[0048] In some embodiments of this application, the characteristics of the latter part of the brake pedal stiffness curve are simulated by setting parameters such as the stiffness of the limiting rubber, the initial position coordinates of the contact point between the pedal arm and the center point of the limiting rubber, and the extreme position coordinates of the contact point between the pedal arm and the center point of the limiting rubber.

[0049] Specifically, by setting the stiffness of the limiting rubber, the initial coordinates of the contact point between the pedal arm and the center point of the limiting rubber, and the extreme position coordinates, the characteristics of the brake pedal stiffness curve in the latter part of the long stroke stage can be accurately simulated. The stiffness of the limiting rubber determines the nonlinear support stiffness exhibited by the system when the pedal stroke increases and the pedal arm begins to compress the limiting rubber, directly affecting the growth slope of the pedal force at the end of the stroke and the overall firmness of the "feel". The initial coordinates of the contact point between the pedal arm and the center point of the limiting rubber are used to determine when the limiting rubber begins to be compressed, that is, to determine the intervention timing of the stiffness curve transitioning from the linear growth stage to the limiting stage. The extreme position coordinates reflect the maximum stroke that the limiting rubber can be compressed, and together with its own stiffness, they constrain the deformation range and reaction force output of the rubber during the compression process. By reasonably setting these three parameters, the stiffness increase or saturation phenomenon caused by the intervention of the limiting rubber when the pedal is close to the full stroke can be accurately reproduced in the simulation, thus completely restoring the mechanical behavior of the latter part of the brake pedal stiffness curve and ensuring that the simulation results are highly consistent with the actual physical characteristics.

[0050] In some embodiments of this application, the key parameters to be adjusted include at least one of the following: the hinge point coordinates of the spring assembly and the pedal arm, the hinge point coordinates of the spring assembly and the friction assembly, the hinge point coordinates of the friction assembly and the pedal bracket, and the initial position coordinates of the contact point between the pedal arm and the center point of the limiting rubber, in order to change the force transmission lever ratio.

[0051] In some embodiments of this application, by adjusting at least one of the following: the hinge point coordinates of the spring assembly and the pedal arm; the hinge point coordinates of the spring assembly and the friction assembly; the hinge point coordinates of the friction assembly and the pedal bracket; and the initial position coordinates of the contact point between the pedal arm and the center point of the limiting rubber, the force transmission path and lever arm length relationship in the pedal system can be effectively changed, thereby adjusting the equivalent lever arm of the force exerted by each component on the pedal. This change in geometric relationship directly affects the amplification or reduction of the spring force, friction torque, and limiting rubber reaction force when transmitted to the pedal application point, i.e., it changes the force transmission lever ratio. By optimizing these key hard point coordinates, the force feedback characteristics of the pedal at different stroke stages can be flexibly controlled without replacing the core components, achieving precise adjustment of the overall trend or local slope of the pedal stiffness curve, and providing an effective structural parameter adjustment means for matching the target stiffness curve.

[0052] In some embodiments of this application, the target pedal stiffness curve is a three-segment curve, including: In the first stage, the pedal travel is 0 to 21 mm. The first and second springs are compressed together, and the rotational friction torque is superimposed. The pedal force increases approximately linearly with the pedal travel.

[0053] In the second stage, the pedal travel is from 21mm to 58mm. The first spring reaches its maximum compression stroke, and the second spring continues to compress. At the same time, the rotational friction torque is superimposed, and the pedal force increases linearly with the pedal travel, while the slope decreases.

[0054] In the third stage, when the pedal travel is greater than 58mm, the second spring continues to compress, the pedal arm compresses the limiting rubber, and at the same time, the rotational friction torque is superimposed, the pedal force increases linearly with the pedal travel, and the slope further decreases.

[0055] Specifically, the target pedal stiffness curve is defined as a three-segment characteristic with clear physical meaning, used to accurately guide the parameter matching and adjustment of the simulation model. The first segment (0 to 21 mm) corresponds to the initial pedal pressing stage, where the first and second springs are compressed simultaneously. The system stiffness is dominated by the parallel stiffness of the two springs, superimposed with the rotational friction torque of the shaft, making the pedal force increase approximately linearly with the travel, simulating a smooth response when lightly pressing. In the second segment (21 mm to 58 mm), the first spring has reached its maximum compression travel and stops working, while only the second spring continues to compress. The system stiffness decreases, resulting in a smaller slope for the pedal force increase. At the same time, the rotational friction torque is still superimposed, forming a linear but gentler force increase characteristic in the middle segment, reflecting the gradual feedback in the stage of enhanced braking intent. In the third segment (pedal travel greater than 58 mm), the high-load stage begins. While the second spring continues to compress, the pedal arm begins to contact and compress the limiting rubber. The nonlinear stiffness of the limiting rubber intervenes, working together with the second spring and the rotational friction torque to make the pedal force continue to increase but the slope further decreases, providing a firm foot feel at the end of the travel and overload protection. The three-segment target curve not only realistically reflects the phased mechanical behavior of the dry brake pedal during actual operation, but also provides a clear performance benchmark for the phased optimization of simulation parameters.

[0056] In some embodiments of this application, the fitting error between the brake pedal stiffness curve obtained by adjusting parameters and the target curve is ≤5%, which serves as a criterion for optimization convergence. This provides a clear and quantifiable accuracy requirement for the simulation parameter tuning process of brake pedal stiffness. This indicator means that the deviation between the simulated pedal force value and the preset target force value is strictly controlled within 5% throughout the entire pedal travel range, ensuring that the simulation results have high accuracy and engineering usability. This error limit considers both the tolerance range allowed by the actual product and ensures the consistency and reliability of the pedal feel, avoiding design errors or repeated modifications due to excessive simulation deviations. By using this error standard as the termination condition for parameter adjustment, the simulation optimization process can be effectively guided, development efficiency can be improved, and a reliable technical basis can be provided for subsequent physical prototype verification and mass production.

[0057] In a specific embodiment of this application, as shown in Table 1, for a certain vehicle model, the brake pedal stiffness target curve is set, with the pedal force increasing from 18N to 500N with the travel. Parameter matching and optimization are performed using the modeling and simulation method described in this invention. After building a simulation model including the pedal arm, spring assembly, and friction assembly in AMESim software, the coordinates of key hard points are set: the pedal point is [1604.89mm, 1235.73mm], and the pedal pivot point is [1503.84mm, 1409.04mm], and the positions of each hinge point are configured; simultaneously, the friction material stiffness of the friction assembly is set to 10. 9 N / m, thickness 3mm, coefficient of friction 0.4; Regarding spring parameters, the first spring is set with a preload of 45N, stiffness of 6.518N / mm, and maximum compression stroke of 4.63mm; the second spring has a preload of 45N, stiffness of 30.696N / mm, and maximum compression stroke of 19.24mm. For example... Figure 2 As shown, the simulation calculations show that the generated pedal stiffness curve is in high agreement with the target data, verifying that the method can effectively achieve accurate simulation and rapid parameter matching of the stiffness characteristics of dry brake pedals in practical engineering applications.

[0058] Table 1. Example of target data for brake pedal stiffness of a certain vehicle model

[0059] In some embodiments of this application, an improved genetic algorithm is used to optimize key parameters of the brake pedal. First, 100 initial parameter combinations, including pedal hardpoint coordinates, spring parameters, and friction component parameters, are randomly generated, ensuring that each set of parameters satisfies the constraints that "the stiffness of the first spring is less than the stiffness of the second spring, and the maximum compression stroke of the first spring is less than the maximum compression stroke of the second spring." Using the deviation between the simulated pedal force-stroke curve and the target curve as the optimization objective, parameters are iteratively updated through selection, crossover, and mutation operations: parameter combinations with smaller deviations are prioritized; selected parameters are cross-recombined to generate new combinations; and some parameters are randomly mutated. When the deviation no longer decreases after five consecutive generations of optimization, the mutation probability is increased to escape local optima until the average deviation between the simulated curve and the target curve is ≤5%, at which point the optimal parameter combination is output.

[0060] In some embodiments of this application, the temperature adaptability of the parameters is verified through multi-condition simulation. Specifically, this includes correcting the rubber stiffness and friction coefficient of the pedal hysteresis friction component under low temperature (-30℃), normal temperature (25℃), and high temperature (85℃) conditions—the rubber stiffness increases linearly with decreasing temperature (stiffness increases by 0.8 N / mm for every 1℃ decrease in temperature) and decreases linearly with increasing temperature; the friction coefficient increases by 15% under low temperature conditions and decreases by 10% under high temperature conditions. Stiffness curves are re-simulated for each temperature condition. If the deviation rate between the curves under different conditions and the target curve is ≤5%, the parameters are deemed to meet the requirements for use across the entire temperature range; otherwise, the parameter optimization steps are returned for readjustment.

[0061] Secondly, this application provides a stiffness modeling and simulation system for a dry brake pedal simulator, comprising the following modules: The model building module is used in AMESim software to build a brake pedal stiffness simulation model based on the mechanical structure of a dry brake pedal simulator. This model includes the pedal arm, pedal bracket, spring assembly, friction assembly, and limiting rubber. The module's function is to construct a multibody dynamics simulation platform consistent with the actual physical structure, accurately reproducing the connection relationships, motion constraints, and force paths between the various components of the pedal system. This provides a reliable digital foundation model for subsequent mechanical analysis, ensuring that the simulation process truly reflects the dynamic behavior of the pedal during pedal application.

[0062] The parameter input module is used to determine the key parameters affecting the brake pedal stiffness based on the brake pedal's structure and working principle, and to set them in the brake pedal stiffness simulation model. These key parameters are used to simulate the spring force characteristics of the spring assembly, the rotational friction torque characteristics of the friction assembly, and the rubber force characteristics of the limiting rubber. The module's function is to parameterize and assign the geometric dimensions, material properties, and mechanical characteristics of the actual system to the simulation model, enabling accurate characterization of the spring's compression characteristics, the friction assembly's resistance torque, and the nonlinear support behavior of the limiting rubber, thus providing accurate input conditions for subsequent force calculations.

[0063] The force calculation module, based on the principle of torque balance, calculates the contribution of the spring force generated by the spring assembly (after lever conversion) to the pedal force as the first contribution, the contribution of the rotational friction torque generated by the friction assembly (after lever conversion) to the pedal force as the second contribution, and the contribution of the rubber force generated by the limiting rubber (after lever conversion) to the pedal force as the third contribution. This module decouples and analyzes multiple mechanical sources in the pedal system, quantifying the independent contributions of the spring, friction, and limiting rubber to the pedal force at different strokes. Through the lever principle, it equivalently converts the forces or torques of each component to the pedal's point of application, enabling the separate calculation of pedal forces and improving the interpretability and engineering guidance of simulation results.

[0064] The parameter optimization module calculates the brake pedal force based on the first, second, and third contribution factors, generates a curve showing the relationship between the brake pedal force and pedal travel, and adjusts key parameters to ensure the curve closely matches the preset target pedal stiffness curve. This module synthesizes the individual pedal forces into a total pedal force, generating a complete pedal stiffness characteristic curve. By comparing the simulation results with the target curve, it iteratively adjusts key geometric or material parameters in the model to optimize pedal stiffness, ultimately ensuring that the force-travel characteristics output by the simulation model meet design requirements.

[0065] In some embodiments of this application, the system provides a graphical user interface (GUI) for setting parameters, previewing effects, and generating reports. The GUI includes a parameter input unit, a stiffness curve visualization unit, and a simulation report output unit.

[0066] In the parameter input unit, the user sets key parameters of the brake pedal through input boxes or drop-down menus, including: brake pedal tread point coordinates, pedal arm pivot point coordinates, pedal arm initial position limit point coordinates, pedal arm and limit rubber center point contact point initial position coordinates, pedal arm and limit rubber center point contact point extreme position coordinates, spring assembly and pedal arm hinge point coordinates, spring assembly and friction assembly hinge point coordinates, friction assembly and pedal bracket hinge point coordinates, friction assembly and friction material upper surface geometric center point coordinates at the initial position of the friction assembly, friction material thickness in the friction assembly, friction material stiffness in the friction assembly, friction coefficient between friction material in the friction assembly and pedal arm pivot, pedal arm pivot radius, spring assembly preload of the first spring, spring assembly stiffness of the first spring, spring assembly maximum compression stroke of the first spring, spring assembly preload of the second spring, spring assembly stiffness of the second spring, spring assembly maximum compression stroke of the second spring, limit rubber length, and limit rubber stiffness. The parameter input unit serves to graphically and standardize the complex simulation parameter configuration process, lowering the barrier to entry and ensuring that users can accurately and completely input their design intent into the simulation system, providing a reliable data foundation for subsequent modeling and calculation.

[0067] The stiffness curve visualization unit generates and displays the relationship curve between brake pedal force and pedal travel in real time. This curve includes segmented characteristics of the first, second, and third segments, and labels the corresponding pedal travel range and force value range for each stage. This allows for a visual preview of the stiffness characteristics of the dry brake pedal simulator. By labeling the travel range and force value range for each stage, this unit enables users to instantly preview the pedal stiffness characteristics under the current parameter combination, facilitating quick assessment of whether the simulation results meet expectations and improving debugging efficiency and user experience.

[0068] The simulation report output unit automatically generates analysis reports in various formats, including a list of key parameters, simulated stiffness curve images, curve fitting error analysis, and key parameter adjustment suggestions. The fitting error analysis includes the maximum deviation and average deviation rate between the simulated curve and the target stiffness curve. Parameter adjustment suggestions are generated based on the sensitivity analysis of each parameter to the stiffness curve. Its function is to systematically record the simulation process and results, provide quantitative evaluation indicators, and offer optimization directions. This not only enhances the traceability and deliverability of simulation results but also provides data support and guidance for engineering decisions.

[0069] Furthermore, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the aforementioned dry brake pedal simulator stiffness modeling and simulation method.

[0070] In summary, the dry brake pedal simulator stiffness modeling and simulation method, system, and product provided in this application have the following technical effects.

[0071] This application embodiment constructs a complete physical simulation model in AMESim software, including the pedal arm, bracket, spring assembly, friction assembly, and limiting rubber, realistically reproducing the mechanical structure and motion relationship of the dry brake pedal, ensuring the accuracy of the simulation basis. By systematically setting key parameters covering geometric layout, material properties, and mechanical parameters, the physical behavior of spring force, rotational friction torque, and nonlinear stiffness of the limiting rubber is comprehensively characterized, improving the model's refinement. Based on the torque balance principle, the contribution of each component to the pedal force is decoupled into first, second, and third contribution degrees, realizing the interpretability analysis of the pedal force source and enhancing the transparency and engineering guidance value of the simulation process. By generating a brake pedal force-stroke relationship curve and comparing it with a preset three-segment target stiffness curve, combined with iterative adjustment of key parameters, precise matching and optimization of the pedal stiffness characteristics are achieved.

[0072] The system further introduces a graphical user interface, integrating parameter input, real-time visualization of stiffness curves, and automatic generation of simulation reports, significantly improving ease of operation, debugging efficiency, and deliverability of results. The overall solution not only solves the problem of traditional design relying on experience and trial and error, but also provides efficient, reliable, and visualized technical means for the forward development, performance prediction, and rapid parameter tuning of dry brake pedals, greatly shortening the development cycle, reducing development costs, and showing good prospects for engineering applications.

[0073] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this application are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and sub-operations described as part of a larger operation are executed independently.

[0074] Furthermore, although this application is described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding this application. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of ordinary skill of an engineer. Therefore, those skilled in the art can implement the application set forth in the claims using ordinary skill. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of this application, which is determined by the full scope of the appended claims and their equivalents.

[0075] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several programs to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0076] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequential list of executable programs for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, a program execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can retrieve and execute a program from or in conjunction with such a program execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can mean any means that can contain, store, communicate, propagate, or transmit a program for use by or in conjunction with a program execution system, apparatus, or device.

[0077] More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Additionally, computer-readable media can even be paper or other suitable media on which programs can be printed, for example, by optically scanning the paper or other media, then editing, interpreting, or, if necessary, processing it in a suitable manner to obtain the program electronically, and then storing it in computer memory.

[0078] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable program execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0079] In the foregoing description of this specification, the reference to terms such as "one embodiment / implementation," "another embodiment / implementation," or "certain embodiments / implementations," etc., indicates that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in an embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0080] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0081] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A method for stiffness modeling and simulation of a dry brake pedal simulator, characterized in that, Includes the following steps: In AMESim software, based on the mechanical structure of the dry brake pedal simulator, a brake pedal stiffness simulation model is built, including the pedal arm, pedal bracket, spring assembly, friction assembly, and limiting rubber. Based on the structure and working principle of the brake pedal, the key parameters affecting the stiffness of the brake pedal are determined and set in the brake pedal stiffness simulation model; the key parameters are used to simulate the spring force characteristics of the spring assembly, the rotational friction torque characteristics of the friction assembly, and the rubber force characteristics of the limiting rubber. Based on the principle of torque balance, the contribution of the spring force generated by the spring assembly to the pedal force after lever conversion is calculated as the first contribution, the contribution of the rotational friction torque generated by the friction assembly to the pedal force after lever conversion is calculated as the second contribution, and the contribution of the rubber force generated by the limiting rubber to the pedal force after lever conversion is calculated as the third contribution. The brake pedal force is calculated based on the first contribution, the second contribution, and the third contribution, and a relationship curve between the brake pedal force and the pedal travel is generated. The key parameters are then adjusted so that the relationship curve fits the preset target pedal stiffness curve.

2. The method for stiffness modeling and simulation of a dry brake pedal simulator according to claim 1, characterized in that, The key parameters include: the brake pedal tread point coordinates, the pedal arm pivot point coordinates, the initial position limit point coordinates of the pedal arm, the initial position coordinates of the contact point between the pedal arm and the center point of the limit rubber, the extreme position coordinates of the contact point between the pedal arm and the center point of the limit rubber, the hinge point coordinates of the spring assembly and the pedal arm, the hinge point coordinates of the spring assembly and the friction assembly, the hinge point coordinates of the friction assembly and the pedal bracket, the geometric center point coordinates of the upper surface of the friction material in the friction assembly at the initial position, the thickness of the friction material in the friction assembly, the stiffness of the friction material in the friction assembly, the coefficient of friction between the friction material in the friction assembly and the pedal arm pivot, the pedal arm pivot radius, the preload of the first spring in the spring assembly, the stiffness of the first spring in the spring assembly, the maximum compression stroke of the first spring in the spring assembly, the preload of the second spring in the spring assembly, the stiffness of the second spring in the spring assembly, the maximum compression stroke of the second spring in the spring assembly, the length of the limit rubber, and the stiffness of the limit rubber.

3. The method for stiffness modeling and simulation of a dry brake pedal simulator according to claim 2, characterized in that, The stiffness of the first spring is less than that of the second spring, and the maximum compression stroke of the first spring is less than that of the second spring. The parameters of the first spring are set to simulate the initial characteristics of the brake pedal stiffness curve, and the parameters of the second spring are set to simulate the middle and later characteristics of the brake pedal stiffness curve.

4. The method for stiffness modeling and simulation of a dry brake pedal simulator according to claim 2, characterized in that, The method for calculating the rotational friction torque is as follows: the normal force of the spring assembly on the friction assembly, the coordinates of the hinge point between the spring assembly and the friction assembly, the coordinates of the hinge point between the spring assembly and the pedal arm, the coordinates of the hinge point between the friction assembly and the pedal bracket, the coordinates of the geometric center point of the upper surface of the friction material in the friction assembly at the initial position, the thickness of the friction material in the friction assembly, and the stiffness of the friction material in the friction assembly are used to calculate the normal force of the friction assembly on the pedal arm shaft. Then, the friction force is calculated based on the friction coefficient between the friction material in the friction assembly and the pedal arm shaft. Finally, the rotational friction torque is obtained by multiplying the friction force by the radius of the pedal arm shaft.

5. The method for stiffness modeling and simulation of a dry brake pedal simulator according to claim 2, characterized in that, The characteristics of the latter part of the brake pedal stiffness curve are simulated by setting parameters such as the stiffness of the limit rubber, the initial position coordinates of the contact point between the pedal arm and the center point of the limit rubber, and the extreme position coordinates of the contact point between the pedal arm and the center point of the limit rubber.

6. The method for stiffness modeling and simulation of a dry brake pedal simulator according to claim 2, characterized in that, The key parameters to be adjusted include at least one of the following: the hinge point coordinates of the spring assembly and the pedal arm, the hinge point coordinates of the spring assembly and the friction assembly, the hinge point coordinates of the friction assembly and the pedal bracket, and the initial position coordinates of the contact point between the pedal arm and the center point of the limiting rubber, in order to change the force transmission leverage ratio.

7. The method for stiffness modeling and simulation of a dry brake pedal simulator according to claim 2, characterized in that, The target pedal stiffness curve is a three-segment curve, including: In the first stage, the pedal travel is 0 to 21 mm. The first and second springs are compressed together, and the rotational friction torque is superimposed. The pedal force increases approximately linearly with the pedal travel. In the second stage, the pedal travel is from 21mm to 58mm. The first spring reaches its maximum compression stroke, the second spring continues to compress, and at the same time, the rotational friction torque is superimposed. The pedal force increases linearly with the pedal travel, and the slope decreases. In the third stage, when the pedal travel is greater than 58mm, the second spring continues to compress, the pedal arm compresses the limiting rubber, and at the same time, the rotational friction torque is superimposed, the pedal force increases linearly with the pedal travel, and the slope further decreases.

8. A stiffness modeling and simulation system for a dry brake pedal simulator, characterized in that, Includes the following modules: The model building module is used in AMESim software to build a brake pedal stiffness simulation model, including pedal arm, pedal bracket, spring assembly, friction assembly and limiting rubber, based on the mechanical structure of the dry brake pedal simulator. The parameter input module is used to determine the key parameters affecting the stiffness of the brake pedal based on its structure and working principle, and to set them in the brake pedal stiffness simulation model. The key parameters are used to simulate the spring force characteristics of the spring assembly, the rotational friction torque characteristics of the friction assembly, and the rubber force characteristics of the limiting rubber. The force calculation module is used to calculate the contribution of the spring force generated by the spring assembly to the pedal force after lever conversion based on the torque balance principle, as the first contribution; the contribution of the rotational friction torque generated by the friction assembly to the pedal force after lever conversion, as the second contribution; and the contribution of the rubber force generated by the limiting rubber to the pedal force after lever conversion, as the third contribution. The parameter optimization module is used to calculate the brake pedal force based on the first contribution, the second contribution, and the third contribution, generate the relationship curve between the brake pedal force and the pedal stroke, and adjust the key parameters so that the relationship curve fits the preset target pedal stiffness curve.

9. The dry brake pedal simulator stiffness modeling and simulation system according to claim 8, characterized in that, The system provides a graphical user interface for setting parameters, previewing effects, and generating reports. The interface includes a parameter input unit, a stiffness curve visualization unit, and a simulation report output unit. In the parameter input unit, the user sets key parameters of the brake pedal through input boxes or drop-down menus, including: brake pedal tread point coordinates, pedal arm pivot point coordinates, pedal arm initial position limit point coordinates, pedal arm and limit rubber center point contact point initial position coordinates, pedal arm and limit rubber center point contact point extreme position coordinates, spring assembly and pedal arm hinge point coordinates, spring assembly and friction assembly hinge point coordinates, friction assembly and pedal bracket hinge point coordinates, friction assembly and friction material upper surface geometric center point coordinates when the friction assembly is in its initial position, friction material thickness, friction material stiffness, friction coefficient between friction material and pedal arm pivot, pedal arm pivot radius, spring assembly preload, spring assembly stiffness, spring assembly maximum compression stroke, spring assembly preload, spring assembly stiffness, spring assembly maximum compression stroke, limit rubber length, and limit rubber stiffness. In the stiffness curve visualization unit, the relationship curve between brake pedal force and pedal travel is generated and displayed in real time. The relationship curve includes the segmented characteristics of the first segment, the second segment and the third segment, and marks the pedal travel range and force value range corresponding to each stage, which is used to intuitively preview the stiffness characteristics of the dry brake pedal simulator. The simulation report output unit automatically generates analysis reports in various formats, including a list of set key parameters, a simulated stiffness curve image, a curve fitting error analysis, and key parameter adjustment suggestions. The fitting error analysis includes the maximum deviation value and average deviation rate between the simulated curve and the target stiffness curve. The parameter adjustment suggestions are generated based on the sensitivity analysis of each parameter to the stiffness curve.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the stiffness modeling and simulation method for the dry brake pedal simulator as described in any one of claims 1 to 7.

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