【作者】 王学新；

【导师】 钟志华；

【作者基本信息】 湖南大学 ， 车辆工程， 2010， 硕士

【摘要】 随着人们对汽车性能要求的日益提高,如何有效提高汽车在高速状态下的操纵稳定性等性能,成为当今行业研究的热点问题。而悬架系统的性能由于直接影响着汽车的整体表现,成为汽车研发的关键之一。本文是国家重大专项“中国高水平汽车自主创新能力建设”子项目之一,旨在针对中气轿车上应用的前四连杆式、后拖臂四连杆式悬架系统,进行性能分析；并确定合适的操纵稳定性客观评价指标,对影响其动态表现的底盘参数进行探讨,为该项目后期的改进设计及调校工作提供理论依据与工程导向。首先,利用ADAMS/Car软件建立了前四连杆、后拖臂四连杆的悬架系统模型。模型充分考虑了橡胶衬套等组件的力学特性,具有较高的精细度与完整度。依据此模型,对中气轿车前后悬架系统的K&C(运动学与柔度)特性进行了详尽的分析。分析结果显示了该套悬架系统良好的性能。为方便对底盘参数产生的影响进行探讨,其次在CarSim软件中建立了完整的中气轿车动力学模型。同时利用“魔术公式”轮胎模型对轮胎的试验数据进行拟合,有效提高了模型的精度。再次,分析比较了国内外几种较为完整的操纵稳定性客观评价体系,结合近些年的研究成果,提出了一套适用于中气轿车的操纵稳定性的客观评价体系及试验方法。体系中的指标充分涵盖了汽车稳态特性、瞬态时域特性及瞬态频域特性3个方面,具有较高的完整度。随后,依据已经建立的客观评价体系,对影响整车操纵稳定性的多种底盘参数进行了深入探讨。这些参数分为2部分10个方面：1.影响车轮载荷的因素。包括轴荷分配、侧倾刚度分配、减振器阻尼系数、减振器压缩／回弹阻尼分配共4个方面。2.影响车轮定位的因素。包括转向系柔度、静态车轮束角、侧倾转向、侧向力顺从转向、静态车轮外倾角、侧倾外倾共6个方面。最后,对2部分的参数进行了综合比较,得出了操纵稳定性各个指标对各个参数的影响敏感度表。并据敏感度表对中气轿车的底盘部分参数进行了重新设置。对比结果表明中气轿车的操纵稳定性有明显的提升。更多还原

【Abstract】 Along with the increasing demands for the improvement of automotive performance, how to elevate vehicle handling under high-speed effectively becomes a hot issue in automotive industry nowadays. Suspension system, which affects vehicle’s behavior directly, is one of the key points in the R&D process of automobiles.This thesis is one of the sub-projects in the national major project "Independent Creative Capability-construction of High-level Automobile China", focusing on the performance analysis of the front four-link and rear trailing-arm four-link suspension system equipped on Zhongqi sedan, and determine proper objective evaluation indexes of handling for the discussion of the chassis parameters affecting vehicle’s dynamical behavior. The study will provide theoretical basis as well as engineering guidance for the later design improvement and vehicle tuning.In the initial pahse, front four-link, rear trailing-arm four-link suspension system model were estabilished in ADAMS/Car. The model, which thoroughly considered the components mechanical characteristics such as bushing, has relatively high precision and completeness. Then the K&C (Kinematics & Compliance) analysis of front and rear suspension system was conducted in detail. The results showed excellent performance of the system.Next, a complete dynamical model of Zhongqi sedan was built in CarSim software for the convenient discuss of the chassis parameters. Meanwhile, the tire experiment data was fit using Magic Formula tire model, which improves the accuracy of the model effectively.Afterwards, the comparison and analysis of several relatively complete objective assessment system of handling in China and aboard were performed, and a new objective evaluation system of handling and stability which can be applied to Zhongqi sedan was brought out after combining the research results recent years. The system, which covers vehicle’s characteristics in steady-state, transient time domain as well as frequency domain, has relatively high completeness.The thesis then discussed multi chassis parameters affecting vehicle handling thorougly. These parameters, which involved ten aspects, were divided into two categories:1. Parameters affecting wheel loads, including 4 aspects which are weight distribution, roll stiffness distribution, shock absorber damping ratio, shock absorber C/R ratio (compression/rebound damping ratio).2. Parameters affecting wheel alignments, including 6 aspects which are steering compliance, static toe, roll steer, lateral force steer, static camber, roll camber.Finally, synthetically comparison of the parameters in the two categories above was carried out, and a sensitivity table of each handling index to each chassis parameter was determined as a reslut. Then the chassis parameters of Zhongqi sedan were re-set partly, according to the sensitivity table. Comparison showed distinct elevation of the handling and stability of Zhongqi sedan.更多还原