【作者】 焦凤；

【导师】 陈南；

【作者基本信息】 东南大学 ， 车辆工程， 2004， 硕士

【摘要】 汽车四轮转向(4 Wheel Steering)技术是改善汽车操纵稳定性的主要手段之一。本文从机构动力学仿真的角度,研究4WS汽车的瞬态和稳态操纵动力学特性。主要内容包括: 1. 本文总结了在运用ADAMS/View进行车辆仿真时遇到的一些具有代表性的问题及其解决方法。2. 建立了4WS车辆横摆率跟踪多状态最优控制方程,并且推导出了它的横摆角速度及质心侧偏角与前轮转角的传递函数。3. 为实现车辆的动力学特性在虚拟环境下的仿真和预估,建立了一个整车动力学虚拟模型。动力学模型包括汽车的车身、轮胎模型、悬架系统、转向执行机构。4. 利用ADAMS/View提供的控制工具箱,实现了在高速下转向行驶时按照一定的控制方法对后轮转角大小的控制。5. 按照国标规定的试验条件,模拟考察了在60及80速度下,给以一定的前轮转向角输入及相应的四轮转向控制方法,模型的瞬态和稳态响应特性,包括横摆角速度和侧向加速度的响应特性,以及其他的动力学特性指标。仿真结果表明采用横摆角速度多状态最优控制方法可以大大改善汽车操纵稳定性的瞬态性能。6. 对车辆在一些不同的参数下的行驶特性进行了简单的比较。7. 比较了采用横摆角速度多状态最优控制方法与前后轮转向比是车速函数的四轮转向控制和比例于横摆角速度的后轮转向控制方法的操纵稳定特性。从仿真结果可以看出,对于使用横摆角速度多状态最优控制的4WS车辆,其转向过程中的瞬态操纵稳定性的各项特性均明显优于普通的2WS车辆以及采用其它简单的4WS控制方法控制的车辆,同时保持操纵稳定性的稳态特性不变。更多还原

【Abstract】 Four-wheel-steering (4WS) technology can improve the maneuverability and stability of an automobile. In this paper,mechanism dynamics visual simulation technology has been used to analyze the characteristics of transient and steady dynamic responses of 4WS automobile. Some theoretical and simulation results are drawn out as follows:this paper summarize some means to solve the problems when we use ADAMS to simulation the 4WS automobile.Presents a new 4WS vehicle control algorithm(Multi-variable stabilization control for four-wheel steering vehicle based on yaw-rate tracking)to improve the vehicle dynamic characteristics in a high speed range. One virtual dynamic models are made in this paper. The model consist of car body, tire and road models,suspension systems,steering system and dynamic parameters. We can control the rear-wheel-steering in ADAMS/View with some 4WS vehicle control algorithm.The dynamic responses of the 4WS automobiles at 60 and 80 are got by simulations of virtual models using ADAMS. The simulations of the tests are based on the national standards.Compare the controllability and stability when the automobile running with the different parameters.Test the transient and steady maneuverability of the 4WS automobile by using the visual prototyping model with the different control algorithm.From the results of the simulations,it is shown that if a nonzero input of the rear steering angle are suitably controlled according to the 4WS control algorithm,the transient responses of 4WS automobiles will be significantly improved, such as the lateral acceleration and its yaw angular velocity. Meanwhile,its steady maneuverability is unchangeable.更多还原