新型汽车主动悬架系统及其鲁棒控制研究

【作者】 王莹；

【导师】 陈健；

【作者基本信息】 广东工业大学 ， 测试计量技术及仪器， 2005， 硕士

【摘要】 悬架是汽车的重要组成部分,它位于车身和车轮之间,通常由弹性元件和阻尼元件组成。一般应具有两个主要性能要求:乘坐舒适性和操纵稳定性。而这两个主要性能要求其实存在着冲突和矛盾。 普遍使用的被动悬架因为具有固定的悬架刚度和阻尼系数,只能满足乘坐舒适性和操纵稳定性之问矛盾的折衷。为此,自五六十年代起产生了主动悬架的概念,利用它可以同时改善车辆乘坐舒适性和操纵稳定性之间的矛盾关系。但是因为现有的主动悬架系统的结构复杂、技术性高、成本昂贵、功耗大等缺陷,限制了这种高性能的减振系统在车辆上的广泛应用。 鉴于此,本文在一定理论研究的基础上,提出一种复合式主动悬架系统,试图解决性能与成本之间的矛盾,以推进主动悬架系统的广泛应用。系统采用液压/气动组合结构,同时具有弹簧和阻尼的功能,分别利用液体和气体的压缩性构成了液压弹簧和气弹簧,同时依靠液压缸内的阻尼小孔产生节流作用而形成被动的阻尼力,又因为通过伺服阀控制器可以改变液压流体的质量,从而改变控制力的大小。所以,它同时还具备提供主动阻尼的作用。与传统的螺旋弹簧悬架相比,新的主动悬架系统能确保行驶高度保持稳定而不管载荷如何变化。 本文首先针对两自由度四分之一车用状态方程建立了动力学模型,接着我们开始鲁棒主动悬架系统的设计,首先给出了主动悬架2DOF 1/4车系统控制问题及性能要求的描迷。为协调相互冲突的各性能要求,同时为强调人体对4-8Hz振动频率的敏感性,采用加权输出作为系统控制输出,并以此构成主动悬架增广系统。在此基础上,着重的讨论了H_∞主动悬架设计的理论问题,在基于线性矩阵不等式的基础上,首先给出了基于干扰抑制问题的H_∞控制器,接着给出了输出反馈H_∞鲁棒控制器构造方法。 本文应用MATLAB软件对上述的汽车主动悬架系统和相应的没有受控的悬架系统进行了仿真研究。仿真结果表明,主动悬架系统有效地抑制了人体敏感频率范围内的汽车振动,大大改善了汽车的行驶平顺性,且具有较强的鲁棒性,并且用加权最坏RMS增益法对所设计的主动悬架系统进行了鲁棒性分析。更多还原

【Abstract】 Suspension is the main part of the vehicle, it lies between body and wheels. Usually, the suspension is composed of the spring and damper elements. It has two main performance requirements, ride comfort and handling stability. But the two main performance requirement is conflicted.The passive suspension using at large has fastness spring stiffness coefficient and damper coefficient, so it can only meet the compromise of the conflict among the ride comfort and handling stability at the structure design. Therefore, the active suspension came into being from five or six decades. It can improve the conflict relation among the ride comfort and handling stability. But the active suspension system has some limitation such as complex structure、 high technology 、 valuable cost and big power, where limit the high performance system to apply abroad on the vehicle system.This paper presents a novel active suspension system to resolve the conflict of the performance and the cost base on the theory study. And hope it can advance the abroad appliance of the active suspension system. The novel system which is newly designed uses gas spring/damper unit, then has the spring and damper in the same unit. The compressibility of the fluid and the gas provide the hydraulic spring and the gas spring, and the connecting damper hole provides passive damper force, and the fluid mass in the chambers can be changed using a serve valve controller to get suitable control force. Thus it has the active damper simultaneity. Comparing with the conventional coil-spring suspension, the new active suspension system ensures ride height remains constant regardless of load conditions.Firstly, tow degree-of-freedom DOF the quarter-vehicle’s dynamic model using the state equation has been set up. Secondly, do some work to design robust active suspension. First of all, we give the problem of active suspension 2DOF quarter vehicle system control and description of performance requirements. In order to harmonize conflict performance requirement and emphasize sensitivity of vertical更多还原