外文翻译-基于动力学仿真模型的汽车操纵稳定性研究.doc

密 级分类号编 号成 绩本科生毕业设计 (论文)外 文 翻 译原 文 标 题Vehicle stability enhancement an adaptiveoptimal approach to the distribution oftyre forces译 文 标 题汽车稳定性改善 一种轮胎力自适应优化分布方法作者所在系别机电工程学院作者所在专业车辆工程作者所在班级B13141作 者 姓 名胡嘉俊作 者 学 号201322362指导教师姓名赵秋芳指导教师职称副教授完 成 时 间2017年2月北华航天工业学院教务处制译文标题汽车稳定性改善 一种轮胎力自适应优化分布方法原文标题Vehicle stability enhancementan adaptive optimal approach to the distribution of tyre forces作 者 Roshanbin译 名罗珊鬓国 籍原文出处Proceedings of the Institution of Mechanical Engineers, 2010, Vol.224 摘要：在本论文，基于集成车辆控制概念的车辆稳定性改善被提出了。一种新的刹车和轮胎侧向力的分布自适应优化方法被采用。被考虑的控制输入是每个车轮的单个车轮的转向和刹车。因为一组满足控制目标的独立的轮胎力不容易进行试验,受到两个平等和四个不等式约束的自适应优化问题已经有了一个最优的解决方案。适当的适应机制被建议用来减少直接偏航力矩控制的负面影响,如机车总速度中的不良减少。提出了车辆稳定性增强系统的有效性,尤其通过数字模拟来展示线上平衡轮胎力的最佳形式和无适应机制。综合汽车非线性动力学模型被用于模拟目标。结果表明,该控制系统能有效地利用轮胎的摩擦力和显著提高车辆的稳定性和处理性能。关键词：车辆动力学稳定性、底盘集成控制、自适应最佳分布，轮胎力1 介绍 自1990年代以来车辆动态控制系统一直是热门研究和提高车辆的稳定性和处理特性的发展重点。这些系统的目的是在紧急状况下有效控制车辆。在这方面,通常,两种技术经常被用来影响车辆的行为。这就是主动转向控制(ASC)和直接偏航力矩控制(DYC)。 在ASC技术中，适当的车轮侧滑力被分配给每个轮胎来生成所需的转弯力1。最近,由于出现了新主题：线控转向系统，ASC研究日趋进步。这个系统在轿车方向盘和车轮之间增加典型的机械联动装置与电线2。 第二种方法是基于独自控制车轮的驱动和制动力,以生成一个偏航力矩。换句话说,DYC系统通过产生对左右轮胎3-4的细微纵向力来直接控制偏航力矩。每个控制技术都有使其在一些特殊情况下无效的局限性。 对轮胎特性的研究表明,甚至外侧力接近饱和是，纵向力也通常不会达到其饱和状态,。因此,DYC不仅是有在线性轮胎摩擦圆的范围内有效,在非线性范围内也有效,而ASC系统当轮胎外侧力接近饱和时(5、6)则变得不那么有效。此外,所有轮胎摩擦圆范围内使用DYC可能导致令人不舒服的驾驶条件,如在非紧急条件下车辆的总速度的良性改变。DYC所有的一个更大的问题是在不转动车轮情况下实现有限的偏航控制。 因为各种车辆动力学的遥相关的强耦合,当独立系统被用来控制车辆动力学的一个特定的功能时,它能对其他特性产生不良影响且因此可以湮灭总控制目标。所以,为了实现车辆控制每个子系统的最大潜力,一个集成的车辆动态控制方案是极其重要的。以最优的方式分配每个子系统的部分,同时,利用所有子系统的最大容量,有效的轮胎力分布方法是很有用处的。在这方面,在所有驾驶情况下，综合控制的策略与最优分布的满足控制目标的轮胎力具有重要意义。虽然不同的控制策略目的都是为了使车辆运动稳定性增加,但对它们之间的优缺点没有明确的答复。此外,还有一个需要更多的关于优化轮胎的使用力的重要的工作,在这方面的工作完成的不多7 - 9。 在本文中,基于集成车辆控制对车辆稳定性改善进行研究。提出了对刹车和轮胎侧向力分布自适应最优方法(AODF)进行研究的新方法。在这方面,利用滑模控制技术使车辆从司机转向角按照预期轨迹行驶。控制器采用偏航率和侧偏角作为输入来计算所需的总偏航力矩和用来指导一个简化的两个自由度(2自由度)车辆(称为自行车模型)侧力。为了分配总偏航力矩和轮胎之间的侧向力，一个自适应最优方法产生了。为了这个目标,两方面的成本函数被发展。这项研究的另一个贡献是适应成本函数的加权系数,以便ASC和DYC子系统以一个最佳的方式集成。通过这种方式,子系统的贡献在于对于集成的车辆动态控制方案根据摩擦圆的概念（这是一个轮胎的固有饱和度特性力的结果）进行调整。为了提高轮胎力的最优分布(ODF)机制的实践部分,在本文中，只有在车辆的车轮的制动力矩是可能情况下考虑。只考虑制动力矩产生的不等式约束优化问题只会使其更加困难。应用Kuhn-Tucker系统,分析优化问题已经解决。后通过对9自由度非线性车辆模型应用有目的的综合控制方案,以MATLAB和Simulink的仿真演示形式证明控制系统的有效性。2 9自由度非线性车辆模型 用于车辆行为模拟的非线性模型是两个系统。在图1中,ms和mus表示的质量中心和簧下质量。移动坐标系(x,y,z)附加到非簧载质量的重心,从簧上质量的位置是由(x位置,y位置,z位置)。9自由度模型包括:在x和y方向纵向和横向运动的实体;车身倾斜,最高点,和相对于x,y,和z轴偏航运动,四个轮子的旋转运动。 以下是假定：1.横滚和俯仰轴的位置的变化可以忽略不计。这些轴平行于道路平面。2.车辆的垂直位移小到可以被忽略。3.不考虑空气动力学的力量。 因此车辆动力学方程给出为： 图一.车辆坐标系统u和v是指车辆的速度分别在纵向和横向方向,p,q,r表示车身倾斜,俯仰和偏航速度分别为张量Iij的元素(i,j 5 x,y,z)代表惯性张量非簧载质量包括对z轴出现和簧下质量m是汽车的总质量。参考文献外文文献Abstract: In this paper, vehicle stability enhancement, based on the integrated vehicle control notion, is presented. A new method for adaptive optimal distribution of braking and lateral tyre forces is employed. The control inputs considered are the individual wheel steering and braking for each wheel. Since a unique set of tyre forces satisfying control objectives cannot be easily determined, an adaptive optimization problem subjected to two equality and four inequality constraints has been solved to achieve an optimal solution. A proper adaptation mechanism is suggested to minimize the negative effects of direct yaw moment control, such as the undesirable decrease in the total speed of the vehicle. The effectiveness of the proposed vehicle stability enhancement system, especially online balancing of tyre forces in an optimal form with and without an adaptation mechanism, is demonstrated through digital simulations. A comprehensive non-linear vehicle dynamics model is utilized for simulation purposes. The results indicate that the proposed control system can effectively utilize the tyres frictional forces and significantly improve the vehicle stability and handling performances.Keywords: vehicle dynamics stability, integrated chassis control, adaptive optimal distribu-tion, tyre forces1.INTRODUCTION Vehicle dynamics control systems have been popular research and development topics for improvement of the vehicle stability and handling characteristics since the 1990s. The purpose of these systems is to actively control the vehicle under emergency situa-tions. In this regard, generally, two techniques have been frequently employed to influence the vehicle behaviour. These are active steering control (ASC) and direct yaw moment control (DYC). In the ASC technique an appropriate wheel side-slip is assigned to each wheel to generate the required cornering force 1. Recently, ASC studies have emerged because of the new subject of steer-by-wire systems. In a passenger car these systems augment the typical mechanical linkage between the steering wheel and wheels with electric wires 2.The second method is based on individual control of the driving and braking forces of the wheels in order to generate a yaw moment. In other words, the DYC system directly controls the yaw moment by gen-erating differential longitudinal forces on the left and right tyres 3, 4. Each control technique has its own limitation that makes it ineffective in some particu-lar situations. An understanding of tyre characteristics reveals that the longitudinal force usually has a margin to its saturation, even when the lateral forces are close to saturation. Thus, DYC is effective not only in linear but also in non-linear ranges of the tyre friction circle, whereas the ASC system becomes less effective when the lateral tyre forces approach saturation 5, 6. Furthermore, using DYC in all ranges of the tyre friction circle could lead to uncomfortable driving conditions, such as desirable change in the total speed of the vehicle in non-emergency conditions. Also a greater problem with DYC is the limited yaw control that can be achieved without steering the wheels.Because of strong couplings of various charac-teristics of vehicle dynamics, when an individual system is used to control one specific feature of vehicle dynamics, it can affect undesirably the other features and, thus, can annihilate the total control objective. Hence, in order to implement the max-imum potential of each subsystem for vehicle control, an integrated vehicle dynamics control scheme is of importance. To assign the portion of each subsystem in an optimal manner and, also, to utilize the maximum capacity of all subsystems, an effective approach for distribution of the tyre forces is useful. In this regard, the strategy of intergrated control together with optimal distribution of tyre forces, in all driving conditions, provided that control objectives are satisfied, has significant im-portance. Although different control strategies have been proposed for vehicle stability augmentation, there is no definite answer to relative merits between them. In addition, there is an important need for more work concerning optimization of the usage of tyre forces, as little work has been done in this area 79. In this paper, vehicle stability enhancement based on integrated vehicle control is studied. A new method for adaptive optimal distribution of the braking and lateral tyre forces (AODF) is proposed. In this regard, the sliding-mode control technique is exploited to make the vehicle follow the desired trajectory obtained from the driver steering angle. The controller uses the yaw rate and side-slip angle as inputs in order to compute the total yaw moment and lateral force required to guide a simplified two-degrees-of-freedom (2DOF) vehicle (known as a bicycle model). In order to distribute the total yaw moment and lateral force between the tyres an adaptive optimal approach is introduced where the longitudinal and lateral forces to be generated by each wheel are determined. For this objective, a cost function consisting of two terms has been devel-oped. Another contribution of this research is to adapt the weighting coefficients in the cost function, so that the ASC and DYC subsystems are integrated in an optimal manner. By this means, the contribu-tions of the subsystems to an integrated vehicle dynamics control scheme are adjusted according to the friction circle notion, which is a consequence of the inherent saturation property of tyre forces. In order to improve the practical aspects of the optimal distribution of the tyre forces (ODF) mechanism, in this paper a vehicle is considered, in which only the braking torque at the wheels is possible. Considering only braking torques generates inequality con-straints in the optimization problem and makes it more difficult. Applying the KuhnTucker conditions, the optimization problem has been solved ana-lytically. Finally, by applying the proposed integra-ted control scheme to a nine-degrees-of-freedom (9DOF) non-linear vehicle model, the effectiveness of the control system is demonstrated through simu-lation using MATLAB and Simulink.2 THE 9DOF NON-LINEAR VEHICLE MODEL The non-linear model used for simulation of vehicle behaviour is a two-mass system. In Fig. 1, ms and mus denote the mass centres of the sprung and the unsprung masses respectively. The moving coordi-nate system (x, y, z) is attached to the mass centre of the unsprung mass, from which the position of the sprung mass is given by (xs, ys, zs). The 9DOF model includes: longitudinal and lateral motions of the body in the x and y directions; body r