含转向系运动副间隙的独立悬架汽车摆振动力学建模与分析

发布时间：2018-04-01 22:21

本文选题：前轮摆振　切入点：独立悬架汽车　出处：《合肥工业大学》2016年硕士论文

【摘要】：麦弗逊式独立悬架和齿轮齿条转向器是目前乘用车最广泛采用的形式,但是该种类型车辆的摆振动力学研究还不够深入。考虑到工程实践中在役车辆由于转向系运动副磨损而导致其摆振响应加剧的现象较为常见,因此应该以类型车辆为研究对象,探寻摆振发生的机理,研究影响摆振的敏感因素。该类独立悬架汽车结构特点为使用齿轮齿条式转向器,“五连杆式”的转向传动机构,断开式的前轴和拥有摆动的主销轴线。根据上述特点,计入转向机构运动副的间隙,应用拉格朗日方程建立了面向独立悬架车辆的八自由度车辆摆振系统动力学模型。通过Rosenbrock算法,对比仿真结果和以往文献的相关试验或经验数据,验证了模型的准确性。基于非线性动力学分析方法,通过大量数值算例,从间隙因素、轮胎因素、悬架因素等三个方面分析汽车结构参数对摆振动力学响应的影响。研究表明间隙大小、间隙接触刚度、轮胎侧偏松弛长度、簧下质量、主销后倾角对摆振有较显著的影响,相关结论可为工程实践提供理论支持。文章最后分析了自激摆振的发生机理,证明了摆角和侧偏角之间产生的不规则相位差使回正力矩对摆角存在能量输入,从而导致了自激摆振的发生。且该能量输入大小直接决定了摆振的剧烈程度。作为内力的间隙接触力同样对系统存在能量输入,可以理解为间隙的存在使系统的负阻尼趋势变大,促进了自激摆振的发生。
[Abstract]:Macpherson independent suspension and gear-rack steering gear are currently the most widely used form of passenger cars. However, the research on shimmy dynamics of this type of vehicle is not deep enough. Considering the phenomenon that the vibration response of in-service vehicle is more common due to the wear of steering system motion pair in engineering practice, the type of vehicle should be taken as the object of study. To explore the mechanism of shimmy and to study the sensitive factors that affect the shimmy, this kind of independent suspension vehicle is characterized by the use of gear-rack steering gear and a "five-bar" steering mechanism. Disconnected front axle and swing main pin axis. Based on the above characteristics, the clearance of the steering mechanism motion pair is taken into account, The dynamic model of eight degree of freedom vehicle shimmy system for independent suspension vehicle is established by using Lagrange equation. By using Rosenbrock algorithm, the simulation results are compared with the relevant experimental or empirical data in previous literatures. The accuracy of the model is verified. Based on the nonlinear dynamic analysis method, through a large number of numerical examples, from the clearance factor, tire factor, The influence of vehicle structural parameters on the dynamic response of shimmy is analyzed from three aspects, such as suspension factors. The results show that clearance size, clearance contact stiffness, tire side slackness length, underspring mass, and the inclination angle of the main pin have a significant effect on the shimmy. The related conclusions can provide theoretical support for engineering practice. Finally, the mechanism of self-excited shimmy is analyzed, and it is proved that the irregular phase difference between the pendulum angle and the lateral deflection angle leads to the energy input of the return moment to the swing angle. This results in the occurrence of self-excited shimmy, and the magnitude of the energy input directly determines the intensity of the shimmy. As an internal force, the gap contact force also has energy input to the system. It can be understood that the existence of clearance increases the negative damping of the system and promotes the occurrence of self-excited shimmy.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.33;U461.61

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