针对车辆动力学特性的液压衬套特性设计

液压控制臂衬套可以大幅度提升车辆的行驶平顺性,文章结合某车型前悬架控制臂液压衬套开发,系统阐述液压衬套动态特性对车辆动力学性能的影响;应用综合法和车辆动力学仿真分析,开发出液压衬套动态特性设计方法,实现了液压衬套特性的前期开发,提升了开发效率。     

悬架控制臂液压衬套与整车平顺性关联分析

为准确分析比较某实车前双横臂悬架安装的液压衬套与传统橡胶衬套对车辆性能的影响,通过试验得到该控制臂液压衬套的静态和动态力学特性,在ADAMS中建立了其力学模型,并在此基础上搭建了整车仿真模型.用谐波叠加法构建了不同等级的随机路面谱.摆臂采用液压衬套和橡胶衬套时,在随机路面和凸块路面上分别对整车模型进行平顺性仿真,通过功率谱估计得到了脚部地板和座椅导轨处垂向和纵向加速度的频谱特性和均方根值,同时分别对整车模型进行了操纵稳定性仿真.最后,对比分析了液压衬套刚度改变对车辆平顺性的影响.结果表明:该车使用液压衬套或传统橡胶衬套对操稳性的影响很小;在A、B级路面上,使用液压衬套时,车辆的平顺性会更好,而对于凸块路面,使用液压衬套时平顺性会差;液压衬套刚度增加后,对于A、B级路面和凸块路面,垂向加速度均方根值有所增大,对于D级路面则变化很小,凸块路面垂向和纵向加速度曲线响应略为变慢,曲线的振荡时间也变长.     

双气室液压互联悬架系统特性研究

为改善车辆动态性能,设计一种双气室液压互联悬架系统.结合结构特征建立双气室液压互联悬架模型,得到包含该模型的整车动力学模型,并利用蛇行试验结果进行验证.将分别装有双气室、单气室的液压互联悬架与原机械悬架的整车模型在不同运动模态下进行仿真,对比分析三者对车辆悬架系统刚度与阻尼特性的影响,并在时域和频域分析三者对车辆响应的...     

橡胶衬套高阶分数导数动力学模型的研究

以某车用摆臂橡胶衬套为研究载体,通过动态加载试验对其轴向频率相关性和振幅相关性进行了研究,建立了基于弹性单元、摩擦单元和高阶分数导数黏弹性单元并联的橡胶衬套模型;提出了一种基于动态邻居广义学习策略粒子群算法的高阶分数导数黏弹性单元参数识别方法,结合试验结果,识别得到了模型参数;进而将分数导数系数拟合为加载振幅的函数,提高了模型的整体预测精度和适用性。经过试验验证,所建立的模型能够精确地描述悬架橡胶衬套轴向的动态特性,对提高悬架系统及整车的动力学仿真精度有一定的意义。     

液压减振器非线性动态仿真和试验

本文建立复杂的减振器台架试验动力学模型,并应用多体系统动力学软件ADAMS开发出双筒液压减振器虚拟样机,进行数值仿真。在虚拟样机中采用的不对称非线性迟滞环足由速度外特性试验曲线拟合而得,突破了常规减振器建模中的速度外特性不对称双线性化模型。比较表明,虚拟样机动态仿真与台架试验结果基本相符。该样机可为优化设计和整车性能匹配提供设计平台。     

双轴转向8×4货车多体动力学仿真分析及系统开发

以多体系统动力学理论为基础,建立了双轴转向8×4货车的多体系统动力学模型,建模过程中考虑了弹簧、阻尼器以及橡胶衬套的非线性特性,并以ADAMS软件为二次开发平台,建立了整车非线性多体动力学仿真分析系统,实现了以下功能:对双轴转向8×4货车整车模型的参数化自动建模功能;按照国标试验工况的自动仿真分析功能;符合汽车评价标准的仿真结果数据后处理功能。最后通过实车试验验证了模型的正确性,在此基础上进行了整车的随机输入平顺性分析。     

淮压减振器非线性动态仿真和试验

本文建立复杂的减振器台架试验动力学模型，并应用多体系统动力学软件ADAMS开发出双筒液压减振器虚拟样机，进行数值仿真。在虚拟样机中采用的不对称非线性迟滞环是由速度外特性试验曲线拟合面得，突破了常规减振器建模中的速度外特性不对称双线性化模型。比较表明，虚拟样机动态仿真与台架试验结果基本相符，该样机可为优化设计和整车性能匹配提供设计平台。     

控制臂舒适性液压衬套的优化设计

控制臂舒适性衬套作为底盘重要弹性零件,起着改善车辆行驶平顺性和整车噪声-振动-声振粗糙度(NVH)的作用,是底盘调试的重要零件。针对双叉臂的下控制臂舒适性液压衬套失效故 障中发生频率最高的衬套开裂问题,从橡胶体结构设计、衬套刚度曲线设定、橡胶材料选择 进行了优化设计和试验验证。结果表明,该优化设计方案可有效解决液压衬套开裂问题。     

悬架控制臂液压衬套动态特性仿真与测试研究

利用有限元流固耦合法及AMESim机械液压系统建模法对某车型悬架控制臂液压衬套的动态特性进行仿真.然后通过试验测试其动态特性并与仿真结果进行对比分析,验证仿真结果的准确性.最后分析控制臂液压衬套主要参数对其动态特性的影响.     

整车多体动力学模型的建立、验证及仿真分析

利用多体动力学方法建立了某轿车的整车非线性多体动力学模型,模型中考虑了前后悬架、转向系统的详细几何结构参数,以及连接处的橡胶衬套、阻尼器的非线性特性,轮胎采用M agic Formu la模型。对所建模型进行了多种试验验证,并分析了该样车的操纵稳定性等相关特性,仿真结果表明所建整车多体模型有较高的精度。     

Sensitivity analysis and optimisation of suspension bushing using Taguchi method and grey relational analysis

In this paper, a novel method is presented for investigating suspension bushing based on mechanical properties of the bushing, their effective directions, spring stiffness and damping coefficient of bushing. The vehicle vibration model and suspension geometry parameters are used to optimise the vehicle suspension based on multi-body dynamics simulation (ADAMS/CAR) initially. Several experiment tests based on ISO 4128 and ISO 7401 have been performed in one of main Iranian automaker (SAIPA) in order to verify the ADAMS/CAR model. The grey relational analysis based on using Taguchi L27 orthogonal array is used to obtain the optimum suspension. Then the bushing characteristics are optimised considering the indicated method. This method considers a combination of ride comfort and handling qualities of vehicle as objective functions simultaneously. The results of optimum suspension are compared with typical Renault Logan which declares the accuracy and efficiency of this method in optimising suspension bushing.     

New nonlinear bushing model for general excitations using Bouc-Wen hysteretic model

Because the characteristics of rubber bushing significantly affect the accuracy of vehicle dynamics simulations, they should be accurately modeled in the vehicle suspension model. In this paper, a new nonlinear bushing model for automotive bushing components is developed to improve the accuracy of vehicle dynamics analysis. Bushing components were first tested to capture the nonlinear and hysteretic behavior of typical elements by using a MTS 3-axis elastomer tester. A simple Bouc-Wen hysteretic differential model was modified to generate a more precise rubber bushing model. A sine wave, step input, and random excitations are imposed on the bushing. The ADAMS program is used to calculate sensitivity and the VisualDOC program is employed to find the optimal parameters for the bushing model. An error function is designed to find optimal parameters of the model. Parameter identification is carried out to satisfy the static and dynamic characteristics due to sine and step excitation inputs. It was proved that the proposed model could predict the bushing forces under sine, step, and random inputs well. The errors are within 10% in the overall range. To show the validity of the proposed model, a numerical example was also carried out. Because the bushing forces due to random excitation input show good agreement with experiments, the proposed bushing model is available in the vehicle dynamics simulation.     

轮胎包容特性分析及其在汽车振动系统建模中的应用

本文分析了轮胎与路面的接触特点，将汽车承载系统简化为二自由度垂直振动系统，建立了同时考虑轮胎几何滤波效应与弹性滤波效应的弹性滚子接触模型。基于刚性滚子模型和弹性滚子模型，仿真出滚子包容后的有效路形。     

基于ADAMS与Matlab的ABS模糊控制仿真研究

将多体系统动力学与智能控制理论相结合对汽车制动防抱死控制系统进行了研究，利用ADAMS／CAR建立了汽车整车的多体力学模型，模型包含了前后悬架、动力总成、转向系统、稳定杆、制动系、轮胎力学模型以及车身，同时也考虑了轮胎、衬套、弹簧、减震器等部件的非线性，准确地表达了车辆的动态特性；利用Matlab／Simulink模糊控制工具箱建立了制动防抱死控制系统的模糊控制策略，利用ADAMS／Control接口进行模型的集成、协同仿真，并将仿真结果与另一种控制策略一逻辑门限值控制的仿真结果进行了比较和分析，仿真反映出模糊控制在整车制动防抱死控制系统上的应用效果，结果表明该控制算法稳定好并具有较强的鲁棒性。     

融合预瞄与势场栅格法的紧急避撞驾驶人模型

紧急避障工况下的驾驶人操作具有响应快且动作幅值较大的特点，传统预瞄驾驶人模型已不能适应紧急避障工况的需求，故考虑实际避撞场景开发相应的驾驶人模型就显得尤为必要。针对此种状况，基于驾驶模拟器，结合紧急避撞工况实际驾驶人操纵数据，提出了一种融合预瞄与势场栅格法的紧急避撞驾驶人模型。首先针对紧急避撞工况下车辆运动特点，建立车辆横、纵向耦合非线性动力学模型，并给出其状态空间方程描述；其次，离线仿真分析紧急避撞系统特征，并结合线性二次型最优控制，建立最优曲率预瞄+跟踪误差反馈驾驶人模型；再者，基于紧急避撞工况下真实驾驶人经验转向行为数据，开发基于势场栅格法的驾驶人模型，为进一步提高驾驶人模型对避障行驶工况的适应性，将基于势场栅格法的驾驶人模型与最优曲率预瞄+跟踪误差反馈驾驶人模型进行融合，并基于Sigmoid函数实现两者输出的权重分配；最后，针对所提出的融合预瞄与势场栅格法的驾驶人模型，开展基于避撞台架的驾驶人在环仿真试验以及实车试验。研究结果表明：在紧急避撞工况下，对比最优曲率预瞄+跟踪误差反馈驾驶人模型，融合预瞄与势场栅格法的驾驶人模型输出的转向动作与实际驾驶人行为较为接近，可在保证避障安全性的前提下，兼顾避障路径跟踪精度与车辆行驶的稳定性。     

某车型后减振器上支座失效分析优化

针对某车型整车道路试验过程中出现的后减振器上支座失效问题,通过查看分析故障件的失效状态,结合应用Abaqus软件进行CAE仿真分析,确定了其失效的主要原因是由于在整车运动过程中,上支座衬套的橡胶凸台的应力太大。对此提出了改进的设计方案,通过台架试验和整车道路试验的验证,结果表明,改进后的后减振器上支座解决了耐久失效问题,同时经整车NVH和操稳性能评价后确认改进方案未对整车性能产生不利影响。     

Validation of the Harshness Problem of Automotive Active Suspensions

The advantages of an automotive fully active suspension system have been promised for many years. Among them, simultaneously achieving good body and wheel mode damping is of the most fundamental. However, implementations of such concepts with hydraulic actuators have generally exhibit worse-than-passive harshness performance when such vehicles are driven through small irregularities on the road. Additional forces are transmitted through the hydraulic active suspension to the vehicle body at high frequencies. Conventional wisdom blames the non-ideal actuator in practice for the problem since most analytical papers assume it an ideal force-producing element. However, the mechanism of generating such excessive force as well as the methodology of solving it has not been systematically demonstrated in the literature. In this paper, a high fidelity mathematical quarter vehicle model is first developed and identified with vehicle test data. This model captures realistic dynamic behaviors of the hydraulic active suspension. The mechanism of creating such harshness problem is then explained with this model. To validate such mechanism, a frequency domain methodology that yields an equal-to-passive high frequency performance while maintaining a good active body behavior was developed based on this model and demonstrated with a test vehicle. The model predicts the test results almost exactly.     

汽车ABS液压调节器建模与分析

汽车ABS液压调节器是ABS的执行机构,它的性能好坏直接影响着汽车制动效能。为研究和评价ABS液压调节器性能,文章在分析调节器的组成和工作原理的基础上,基于AMESim建立了包括液压调节器、制动主缸及制动轮缸的模型,对影响调节器动态响应特性的制动液和控制阀(增、减压阀)结构因素进行了仿真分析;并针对某型号调节器进行了台架试验。试验结果表明,基于AMESim的汽车ABS液压调节器仿真结果与试验结果基本吻合。AMESim建模为调节器的研究提供了一种行之有效的方法。     

Modeling and ratio control of an electromechanical continuously variable transmission

A new type of electromechanical continuously variable transmission (EMCVT) was investigated. The EMCVT uses a direct current (DC) motor to push the driving pulley, which in turn changes the transmission ratio without a hydraulic system. This paper introduces the principle of the EMCVT and establishes a dynamic ratio control model. Ratio control strategies using both position and speed closed-loop control are proposed. Simulation results show that the simulation ratio curves of the EMCVT follow pre-designed ratios well for ramp and sine curves. Control software is based on MATLAB/Simulink/Stateflow and MotoHawk platforms. A prototype vehicle equipped with an EMCVT has been developed. Vehicle test results show that the control performance of the EMCVT satisfies the requirements of vehicle operation. The effectiveness of the EMCVT ratio control strategy proposed in this paper is validated with test data for the prototype vehicle.     

乘用车操稳转向性能指标分解技术应用研究

车辆动力学性能开发包括性能目标设定、目标分解、优化设计、底盘调校,逐渐向目标达成逼近,开发结束后实现目标达成。性能目标分解即指标分解,用简单有物理意义的理论公式关联整车指标与总成指标,将整车的客观性能指标分解至系统特性,是整车性能目标达成的关键环节,在性能开发中承上启下,是各主机厂的核心技术。性能指标分解正常在车辆开发初期,用于指标分解的模型应采用尽可能少的建模参数,建模分析迅速且模型能明确表达系统参数对整车性能的影响规律。ADAMS或CarSim模型,由于模型结构过于复杂,不适用于车辆性能的指标分解。本文建立了用于性能指标分解的模型,并基于此模型研究底盘动力学操稳转向性能指标的分解及应用方法,为车辆动力学性能开发工作提供理论指导。