多刚体系统动力学在汽车转向和悬架系统运动分析中的应用

多刚体系统动力学是近２０年发展起来的力学新分支。本文以该领域中的Ｒ－Ｗ方法为理论基础，编制了可自动建模半进行计算机值仿真计算的汽车转向，悬架运动分析通用程度，运用该程度对大量的实车进行了计算分析，经整车和转向悬架系统的试验结果表明，用该程序进行汽车转向，悬架运动分析，所得结果准确，计算迅速，可方便地进行转向，悬架设计方案的比较和参数的选择。     

基于统一模型的转向-悬架系统最优综合控制方法

通过对车辆底盘系统中的转向和悬架系统建立统一的数学模型,利用M atlab/S imu link仿真,结合最优控制理论,分别对被动悬架兼前轮转向系统与主动悬架兼四轮转向综合控制系统进行了对比研究。理论分析与仿真试验表明,综合控制系统下车辆的操纵稳定性和平顺性都得到了很大的提高。     

汽车转向传动与悬挂系统运动干涉优化

以某中型载货车为例,通过建立前悬挂一转向传动系统的仿真模型,应用ADAMS分析软件,对前悬挂和转向传动系统的运动学特性进行仿真分析,提出优化汽车转向传动系统与悬挂系统之间运动干涉量的方法,解决整车加载过程中方向盘偏转的问题。     

车辆半主动悬架与助力转向集成控制的仿真研究

为协调车辆操纵稳定性和行驶平顺性,基于底盘系统动力学原理,建立了半主动悬架和电动助力转向的综合模型,对半主动悬架和电动助力转向系统进行集成控制.运用二次反馈法和PID策略分别对悬架的可调阻尼和转向系统的助力进行控制.仿真结果表明,在集成控制情况下,车辆的操纵稳定性和平顺性均优于悬架或转向单独控制的效果.     

四轮转向车辆多体仿真与试验研究

以四轮转向原理样车为对象,运用多体动力学理论对四轮转向车辆的转向特性进行了计算机仿真研究和试验验证。对建立整车多体模型的方法进行了论述。通过对仿真数据与样车试验结果的对比分析,证明了四轮转向多体模型各类参数和控制方法的正确性和适用性。最后利用建立的整车多体模型,仿真分析了前后悬架刚度对操纵稳定性的影响,以及制动转向时的转向响应特性。     

面向结构的汽车齿轮齿条式转向系仿真模型

针对齿轮齿条式转向系统建立了面向结构的转向系统模型,包括转向齿条动力学和转向横拉杆以及转向立柱的弹性特性、转向减振器阻尼力、转向干摩擦、液压助力特性等。所建模型具有完备的动力学自由度,能准确地反映路面激励对转向轮运动状态地影响。并将该模型嵌入到整车动力学模型中,对两种典型工况进行了仿真计算。通过仿真结果与道路试验结果的对比,验证了该模型的正确性。     

Process Save Reduction by Macro Joint Approach: The Key to Real Time and Efficient Vehicle Simulation

Applying a non-linear model reduction method to the tire suspension system of road vehicles enables an automatic transfer of complex offline simulation vehicle models to a mathematical model, which fits the real time simulation requirements. The basic assumption, that high frequent inner suspension dynamics are not relevant to handling manoeuvres, converts the differential algebraic equation system (DAE) of suspensions with kinematical closed loops into pure elasto-kinematical linkage equations. The equations of motions can be represented as an ordinary differential equation system (ODE) and considerable simulation time reductions are obtained for the off-line simulation and real time simulation is enabled. This so-called macro joint approach is an alternative modelling method to the well-known look-up table representation of suspension kinematics but it keeps the parameterisation of the original suspension model and is suitable to parameterised real time MBS models. With a second step the dynamics, caused by compliance in the suspension bushings, are reduced to their quasi-static behaviour. The consideration of these quasi-elasticity has nearly no influence on the necessary simulation time. This contribution shows the theoretical background and demonstrates the advantage of the macro joint model reduction approach on a typical vehicle example.     

Process Save Reduction by Macro Joint Approach: The Key to Real Time and Efficient Vehicle Simulation

Applying a non-linear model reduction method to the tire suspension system of road vehicles enables an automatic transfer of complex offline simulation vehicle models to a mathematical model, which fits the real time simulation requirements. The basic assumption, that high frequent inner suspension dynamics are not relevant to handling manoeuvres, converts the differential algebraic equation system (DAE) of suspensions with kinematical closed loops into pure elasto-kinematical linkage equations. The equations of motions can be represented as an ordinary differential equation system (ODE) and considerable simulation time reductions are obtained for the off-line simulation and real time simulation is enabled. This so-called macro joint approach is an alternative modelling method to the well-known look-up table representation of suspension kinematics but it keeps the parameterisation of the original suspension model and is suitable to parameterised real time MBS models. With a second step the dynamics, caused by compliance in the suspension bushings, are reduced to their quasi-static behaviour. The consideration of these quasi-elasticity has nearly no influence on the necessary simulation time. This contribution shows the theoretical background and demonstrates the advantage of the macro joint model reduction approach on a typical vehicle example.     

整车主动悬架系统的数学建模

悬架系统是一个复杂的动力学系统,其模型的精确性、合理性对主动悬架的研究起到决定性作用.为进一步满足车辆乘坐舒适性的要求,以整车模型为研究对象,运用八板块方法进行动力学分析,根据牛顿运动学定律推导出悬架各部分的力学微分方程,从而建立了包含俯仰运动模型、侧倾运动模型和转向运动模型的整车模型,为车辆主动悬架的进一步研究提供了理论基础与依据.     

汽车主动悬架与电动助力转向系统多目标优化及集成控制

建立了整车主动悬架和电动助力转向系统动力学模型,构建线性控制的主动悬架和PD控制的电动助力转向系统集成控制器,应用遗传算法对集成控制系统的结构参数和控制参数进行多目标优化。结果表明,经过多目标优化后的集成控制系统,既可保证车辆操纵轻便性,又显著提高了整车操纵稳定性、安全性和行驶平顺性。     

基于遗传算法和LQG控制的汽车半主动悬架结构和控制参数的集成优化研究

传统半主动悬架的设计是先设计其结构参数后设计其控制器参数，这样易造成系统失去全局最优性能。针对这一问题，本文提出一种基于遗传算法和LQG控制的集成优化半主动悬架结构参数和控制参数的方法，通过理论分析和仿真结果表明此方法与传统优化方法相比，对改善汽车行驶平顺性和提高汽车行驶安全性具有较优的效果。     

基于ADAMS软件的汽车平顺性仿真分析

应用ADAMS／Car软件，建立包括前后悬架、转向系、车身等在内的某车型的多体动力学模型；利用编制的路面谱文件，进行汽车脉冲和随机路面输入的平顺性仿真分析．将仿真后的测量数据输入到编制的平顺性评价程序中．根据国标对分析结果进行评价。     

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。     

Advanced Steering System Adaptable to Lateral Control Task and Driver's Intention

This paper proposes an advanced steering system that adaptively varies the static gain and dynamics of the steering system. The steering system gain is adjusted, depending on whether the driver is in an aggressive or leisurely driving mood. The steering system dynamics is so designed that the command mode of the steering system will be either a rate-command or an attitude-command according to the lateral control task performed by the driver. The recognition system for lateral control tasks, a lane-following or lane-change task is proposed. The findings of simulator tests indicate proposed advanced steering system would remarkably improve the vehicle handling qualities.     

Advanced Steering System Adaptable to Lateral Control Task and Driver's Intention

This paper proposes an advanced steering system that adaptively varies the static gain and dynamics of the steering system. The steering system gain is adjusted, depending on whether the driver is in an aggressive or leisurely driving mood. The steering system dynamics is so designed that the command mode of the steering system will be either a rate-command or an attitude-command according to the lateral control task performed by the driver. The recognition system for lateral control tasks, a lane-following or lane-change task is proposed. The findings of simulator tests indicate proposed advanced steering system would remarkably improve the vehicle handling qualities.     

Vehicle steering returnability with maximum steering wheel angle at low speeds

In this paper, an analytical model with suitable vehicle parameters, together with a multi-body model is proposed to predict steering returnability in low-speed cornering with what is expected to be adequate precision as the steering wheel moves from lock to lock. This model shows how the steering response can be interpreted in terms of vertical force, lateral force with aligning moment, and longitudinal force. The simulation results show that vertical steering rack forces increase in the restoring direction according to steering rack displacement for both the inner and outer wheels. As lateral forces due to side-slip angle are directed toward the medial plane of the vehicle in both wheels, the outer wheel pushes the steering wheel in the returning direction while the inner wheel does not. In order to improve steering returnability, it is possible to increase the total steering rack force in both road wheels through adjustments to the kingpin axis and steering angle. This approach is useful for setting up a proper suspension geometry during conceptual chassis design.     

Vibration path analysis and optimal design of the suspension for brake judder reduction

Brake judder is abnormal vibration, which is mainly generated by uneven contact between the brake disc and pad. The abnormal vibration from BTV (Brake Torque Variation) is transferred to the suspension and the steering system during braking. In this paper, judder simulation is carried out using a multi-body dynamic analysis program to analyze the relationship between judder and the transfer mechanism, which consists of the suspension and the steering system. In order to verify the analytical model, test results are compared with the simulation results. A sensitivity analysis is also carried out. In addition, an optimization method is presented for judder reduction, using the design of experiments.     

基于多目标粒子群优化算法的某轻型商用车操纵稳定性优化研究

针对某轻型商用车稳态回转时侧倾度偏大的问题对其悬架进行优化改进。基于ADAMS/car搭建整车多体动力学模型,通过前悬架反向平行轮跳试验、后悬架理论计算验证了悬架仿真模型的准确性。进行整车稳态回转工况和转向盘中间位置转向工况仿真分析,结果表明,车身侧倾度偏高。为实现操纵稳定性优化分析的流程自动化,提出了基于modeFRONTIER的联合仿真方法。以悬架设计参数为优化变量,以汽车的侧倾度与横摆角速度响应滞后时间为优化目标,采用拉丁超立方试验设计方法拟合得到混合代理模型,并结合多目标粒子群优化算法对悬架系统进行多目标优化,获得了悬架系统优化方案。优化结果显示,在不影响平顺性的前提下,汽车车身侧倾度降低了13.93%,横摆角速度响应滞后时间降低了2.75%,整车操纵稳定性得到了提升。     

双横臂悬架刚柔耦合建模及性能的优化分析

运用ADAMS/Car建立了带转向系统的某大型客车双横臂悬架系统刚柔耦合模型,并进行了悬架运动学仿真,分析并评价了悬架在运动过程中主要性能参数的变化规律及对操纵稳定性的影响,通过比较多刚体模型和刚柔模型的仿真分析结果,证明刚柔耦合模型更加准确.针对悬架出现的问题,利用ADAMS/insight对悬架某些不合理的参数进行...