微车转向器安装座套刚度分析与研究

主要对微型车转向器安装座套刚度进行分析与研究,重点对安装座套结构、计算刚度、橡胶的本构模型选取进行了分析,并在此基础上建立有限元分析模型。在该模型中,考虑了安装座套与壳体的大变形非线性接触、橡胶材料的几何非线性。     

Exploring the roles of portfolio steering committees in project portfolio governance

Governing project portfolios engages different actors in organizations including portfolio managers, portfolio officers, top managers, and others who may team up as portfolio steering committees. While portfolio steering committees play a regular role in project portfolio governance, their role is still unclear. Through an in-depth multiple case study in three Danish companies, the roles of portfolio steering committees were explored. The results showed that portfolio committees may play three distinct roles in portfolio governance: a) communication and consolidation role, b) negotiation role, and c) decision making role. The results challenged the notion that portfolio committee meetings are the place and time to make collective decisions on the portfolio, rather, portfolio steering committees might unintentionally become or intentionally be used for other purposes than decision making. The empirical evidence of the study proposes that these three roles might be related to two governance design factors: frequency and duration of committee meetings.     

Modeling extreme loads acting on steering components using driving events

Forces during steering events, such as curves and maneuvers, cause large stresses on steering components. In this paper, we formulate a model for the lateral loads causing fatigue damage of the steering components. Steering events are identified using a Hidden Markov model on the CAN (Controller Area Network) bus data. The CAN data is available on all vehicles, thus the model is applicable across many types of vehicles. To identify the events, the observation from CAN data is modeled by a multivariate generalized Laplace (GAL) distribution. An explicit formula for the expected fatigue damage is given. Results are validated using measured lateral acceleration.     

Dynamic steering of HPC scientific workflows: A survey

The field of scientific workflow management systems has grown significantly as applications start using them successfully. In 2007, several active researchers in scientific workflow developments presented the challenges for the state of the art in workflow technologies at that time. Many issues have been addressed, but one of them named ‘dynamic workflows and user steering’ remains with many open problems despite the contributions presented in the recent years. This article surveys the early and current efforts in this topic and proposes a taxonomy to identify the main concepts related to addressing issues in dynamic steering of high performance computing (HPC) in scientific workflows. The main concepts are related to putting the human-in-the-loop of the workflow lifecycle, involving user support in real-time monitoring, notification, analysis and interference by adapting the workflow execution at runtime.     

方向盘的发展及研究

汽乍方向盘作为汽车最重要的部件之一,随着汽车的发展也经历了从简单到复杂的过程。主要介绍了方向盘的起源及发展,分析了方向盘主要的材料,重点列举了方向盘h运用的新技术并对方向盘的未来进行了展望。     

工程车辆线控液压制动系统响应特性研究

针对线控液压制动系统响应速度慢、制动轮缸控制稳定性差等问题,并结合本研究系统所具有的非线性特点,设计了适用于线控液压制动系统的模糊控制器。通过结合汽车的实际情况,在Simulink和AMESim软件中搭建了模糊控制器与线控液压制动系统的仿真模型,通过仿真对比相同输入信号下的两种控制算法对该系统响应特性影响。在仿真中,仿真的输入信号为阶跃信号和方波信号,通过分析得出制动轮缸的压力曲线。结果表明:在同一信号下,模糊控制相较于无控制(即无任何控制算法进行控制本研究系统),响应速度提升了0.15 s左右,该控制使系统具有良好的动态特性,满足系统要求。     

转向泵微机测试控制系统

介绍一种基于ＰＣ机＋ＰＬＣ可编程控制器下位机的转向泵微机测试控制系统。ＰＬＣ下位机完成转向泵的压力冲击自动控制、油温自动控制、出厂试验自动控制和压力、流量、温度、转速、转矩等参数的自动测试。ＰＣ机可随时在屏幕上显示已采集到的数据,并打印数据表格和曲线     

交叉变轮距底盘机械式可变特性转向系统研究

分析了变轮距车辆的转向要求及常用转向方法;介绍了一种利用双对角线几何原理实现轮距可变特性的交叉变轮距车辆底盘技术;针对目前国内的机械式转向系统一般不能满足变轮距车辆的转向要求的现状,提出了一种利用基于阿克曼梯形转向机构的可变特性转向单元实现交叉变轮距底盘机械式转向的技术方案。分析结果表明,该方案不仅可以较好地实现交叉变轮距底盘的前轮转向和四轮转向,而且降低了转向机构及其控制程序的复杂程度,提高了转向精度和可靠性,具有较高的理论研究和推广应用价值。     

重型商用车转向节臂疲劳试验研究

转向节臂是重型商用车转向节的关键零部件,其疲劳性能直接影响整车的可靠性和安全性。对转向节臂疲劳试验输入载荷谱的确定和台架试验进行了研究。通过标定转向直拉杆和采集典型转向工况实车载荷谱确定了转向节臂疲劳试验的输入载荷。根据采集到的载荷谱和疲劳累积损伤等效原则制定了转向节臂疲劳试验输入载荷谱,并据此进行了转向节臂的疲劳性能验证试验。疲劳试验有效验证了转向节臂的疲劳性能,找出了可能出现失效的部位,为转向节臂的改进提供了依据。最后对改进过的转向节臂进行了疲劳性能的台架试验验证。     

液压助力转向系统参数对汽车操纵稳定性的影响分析

建立汽车液压转向系统(从转向盘到前轮)的数学模型与仿真模型,并结合二自由度汽车模型,在转向盘转角斜坡输入的情况下,分析液压系统参数对汽车横摆角速度输出的影响。