【作者】 蔡章林；

【导师】 宋传学；

【作者基本信息】 吉林大学 ， 车辆工程， 2004， 硕士

【摘要】 本文以多体系统动力学理论为基础，应用机械系统仿真分析软件ADAMS/CAR，建立了前、后悬架多体系统动力学模型，对前、后悬架系统运动学动力学进行了动态仿真，提出改进设计方案；在前、后悬架分析的基础上建立包括发动机、转向系、前后轮胎等在内的整车模型，并对转向回正、阶跃输入、脉冲输入和稳态回转进行了试验验证，最后对影响整车操纵稳定性的若干因素进行了详细的探讨。全文共分五章：第一章详细总结回顾了汽车系统动力学建模的发展历史、现状以及发展趋势。简要描述了本文的研究内容和意义。系统动力学模型正经历着由简单到复杂，由线性到非线性，由少数零部件到复杂总成的发展历程， 通用的多体仿真代码逐渐被应用。如：ADAMS，MEDYNA，NEWEUL，DADS，AUTOSIM和 SIMPACK等。结合某SUV升级车型开发项目， 阐述了动态仿真在悬架和整车开发中的重要意义。第二章介绍了本文的研究方法——多体系统动力学理论。对目前得到广泛应用的典型多体软件ADAMS的各种模块以及理论基础作了全面的介绍。第三章主要分为两部分。分别阐述了ADAMS/CAR在前悬架和后悬架设计开发中的应用。悬架是汽车的主要总成之一，其对操纵稳定性和平顺性的影响至关重要。传统设计一般采用经验设计、数学计算法以及几何作图等方法，设计虽然可以满足要求，但精度和效率不高，很难满足日益加速的设计需求，为缩短开发周期，降低开发成本，有必要采用新的设计方法。ADAMS/CAR模块内有悬架运动学动力学分析的专门模板，可以方便地建立各种结构形式的悬架，迅速得出悬架的多达三十多种参数的性能曲线。本章针对某升级SUV车的前后悬架进行了运动学动力学仿真分析，揭示了各自的运动规律。针对前双横臂独立悬架抗点/抬头性能较差以及悬架刚度和侧倾角刚度曲线随车轮的上跳迅速下降的变化趋势，在尽量少改动零部件的前提下，将下控制臂与车架前安装点向下调整20mm，结果表明悬架刚度和侧倾角刚度曲线降低趋<WP=86>势得到改善，点/抬头量明显减小。对四连杆非独立悬架的刚度以及车轮中心位移量等重要参数进行了计算，并以车轮中心横向和纵向位移量为优化目标对关键点的位置进行了优化分析并最终提出改进意见。第四章为整车操纵稳定性分析。在前一章悬架分析的基础上建立包括前后悬架、横向稳定杆、转向系、减震器、发动机、驾驶室、车架、轮胎等在内的整车模型。进行多项操纵稳定性仿真分析并与试验结果进行验证，在此基础上对影响整车操纵稳定性的若干因素进行了初步探讨。为评价该该车的操纵稳定性，课题组将汽车作为开路控制系统，依据国标GB/T 6323—1994《汽车操纵稳定性试验方法》，对整车进行蛇形试验、转向瞬态响应试验（转向盘转角阶跃输入）、转向瞬态响应试验（转向盘转角脉冲输入）、转向回正性能试验、转向轻便性试验、稳态回转试验。求出汽车曲线行驶的时域响应与频域响应，根据试验结果，从客观上评价车辆的操纵稳定性能。利用建立的仿真模型对转向盘转角阶跃输入、转向盘转角脉冲输入、转向回正性能试验、稳态回转试验进行仿真分析，与试验进行验证表明模型具有较高的准确度，可以作为改进设计的依据。在此基础上对影响整车性能的若干因素进行了探讨，包括：横向稳定杆刚度、扭杆弹簧刚度、前悬架几何定位参数、轮胎参数、质心位置、载荷。为悬架的改进设计提供保证，对整车的性能起到预测。第五章是全文的总结。叙述了本文的主要工作与研究成果，以及今后的研究方向。本文成功地将动态仿真运用到悬架和整车开发中来，结合试验对悬架和整车产品开发提出求解策略。但要做到动态仿真与实际的完美吻合还有很多工作需要进一步的解决，比如：人－车－路闭环系统对操纵稳定性有很大的影响，因此在进行操纵稳定性分析时有必要考虑人的因素；轮胎与道路的接触问题等等。另外，汽车产品中的控制系统日益成熟，如何在多体模型中建立准确的控制模型依然没有很好的解决。总之，动态仿真是进行汽车悬架及整车产品开发的有效方法。多体系统动力学的相关软件为汽车悬架及整车动力学研究提供了功能强大、行之有效的研究工具。随着计算机和软件技术的不断发展，以多体系统动力学为核心的动态仿真技术在悬架和整车的产品开发中一定会发挥更大的作用。更多还原

【Abstract】 Based on the theory of Multi-Body System Dynamics, multi-body system dynamics models of front and rear suspensions model are built in the Mechanical System Simulation software, ADAMS/CAR, and dynamic simulation off front and rear suspensions system dynamics were performed and the modifying strategies were put forward; the full vehicle model including engine, steering system, front and rear tire etc based on the analysis of front and rear suspension. The experiment validation were made focus on the release of steering, impulse input, step input and constant radius steering. At last we discussed the factors which of them influence the handling and stability of full vehicle. The whole article include five chapters:In chapter one, we reviewed on the growing history, status quo and future trend of vehicle system dynamic modeling. A brief described the research content and significance. The system dynamic model are coming through from simple to complication, from linear to non-linear, from few parts to complicated assembly, the general multi-body codes were gradually used. Such as ADAMS，MEDYNA，NEWEUL，DADS，AUTOSIM and SIMPACK etc. expound the implication of dynamic simulation in suspension and full vehicle development combining with the development project of a updating SUV.In chapter two, introduced the research method----the theory of multi-body system dynamic. the thorough introduction to the modules and theory of ADAMS, one of the most popular multi-body system dynamics software packages. <WP=88>Chapter Three is divided into two parts. Expound the application of ADAMS/CAR in front and rear suspension development respectively. Suspension system is the mainly assembly of vehicle, influence the handling stability and ride comfort greatly. The traditional design methods are experiential design, mathematic calculation and geometrical construct etc, the design can satisfy the requirement but the precision and efficiency is low, can’t keep up the upspeed design requirement, new design method must be adapted in order to shorten the development period and cut cost. ADAMS/CAR module has the professional kinematics and dynamic analysis template for suspension, all kinds of suspension can constructed conveniently and more than thirty kinds of parameters curves about the suspension can be made rapidly. The kinematics and dynamic analysis arm at the front and rear suspension system of a updating SUV, the motion law was uncovered respectively. The front suspension is double wishbone independent suspension, the anti-dive and anti-lift performance is bad and the wheel rate curve and roll stiffness curve descend rapidly along with the wheel travel up, in the guide of modify as few as better of the parts, made the low control arm front point connected to the body 20mm down, the results indicate the wheel rate curve and roll stiffness curve descend trend is slowed, the dive and lift quantity minished a lot. The key parameters such as wheel rate and wheel center displacement is calculated，the optimization analysis of key points was performed at the optimization arm of wheel center longitude and lateral displacement, the modifying strategies were put forward.In chapter four the full car handling stability was performed. The full vehicle simulation mode is built including front and rear suspension, anti-roll bar, steering system, damper, engine, driver room and body, tires etc based on the suspension analysis in former chapter, many handling stability simulation analysis were performed and validated with the experimental results, and elementary discussion about the main influence factors to the handling stability was carried out. In order to evaluate the handling stability the object group have carried out the pylon course slalom test, steering wheel angle step input test, steering wheel angle pulse input test, returnability test, steering efforts test, steady static circular test according to the test methods of handling stability in GB/T6323—1994 looking upon the vehicle as a open loop system. Educed the time dom更多还原