下陷单脊矩形波导传输特性研究

利用亥姆霍兹方程的有限差分格式,研究在下陷单脊矩形波导中,脊在中心位置且几何尺寸变化对传输特性的影响.计算了脊的尺寸变化时的截止波长cλ和单模带宽λc/cλ1,并给出了TE10和TE11模式的场结构图.通过与传统单脊矩形波导的对比,指出了下陷单脊矩形波导传输特性的优缺点.     

高速铁路综合调度系统体系结构的研究

利用计算机最新发展技术,结合高速铁路运输特点,从系统的角度提出基于三层C S体系结构的高速铁路综合调度系统结构模型和体系结构,采用消息中间件技术,构成高速铁路综合调度系统的关键业务平台,实现系统各主要业务的集成,充分利用既有信息系统的成功经验及软件复用技术,构成一个完整、统一、标准的高速铁路综合调度系统。依据本研究结果所设计的高速铁路综合调度系统仿真试验系统已经建成。     

结构模糊可靠性分析

结构破坏准则实际上是带有模糊性的，要合理判断结构强度必须依靠模糊概率方法。本文采用基于模糊判决的限界搜索法，给出了计算结构模糊可靠性清晰解的方法。以受集中力的两端刚固梁和船首底板砰击强度为例进行了数值计算，并讨论了容差变化对模糊可靠度指标的影响。     

汽车三维分离流动特性的数值研究

本文对轿车尾部的分离流进行了数值计算和研究。通过ＳＧＳ（亚网格尺寸比）湍流模型,用瞬态三维Ｎ－Ｓ方程对具有不同尾部外形的汽车流场进行了全模拟。本文论述了计算所得的非稳态流场的时均值。通过计算结果与风洞实验和水槽实验数据的对比分析验证了计算的有效性和可靠性。     

基于尺寸精度的铝合金减震器塔结构设计及优化

铝合金作为一种优质轻量化材料在轻量化车身上的应用越来越广泛,为了确保铝合金零部件的使用功能和性能,设计人员在设计前期就需要对零部件的精度进行设计分析和优化。文章基于一种压铸铝合金减震器塔的零部件,首先对该铝合金零部件精度进行分析摸底并识别出影响该铝合金零部件精度的两个关键要素,再分别针对两个关键要素进行优化设计,重点一是优化加强筋结构,以增加减震器塔本体的刚度和抗变形能力,另外是增加热处理工艺中夹具支撑块结构,通过外力支撑来增加抗变形能力。结果表明:合理的加强筋布置能有效提升减震器塔本体的刚度、强度和尺寸精度;热处理时需设计专用支撑夹具,且支撑夹具要保证所有重要安装面的支撑,避免铝合金减震器塔局部出现悬臂,通过外力支撑来防止变形。     

汽车悬挂上的扭杆弹簧及其应用

在现代汽车设计中,舒适性越来越受到重视,对汽车平顺性的要求也越来越高。为使汽车在行驶当中能够获得适当的操控性与舒适性,扭杆弹簧因此被用作汽车悬挂系统中的减振装置,利用弹簧的变形以吸收能量,缓解汽车在行驶时产生的振动和倾斜,在汽车上担负着十分重要的角色。文章分别介绍汽车悬挂扭杆弹簧的功用特点、结构原理,指出了适用车型,以及扭杆弹簧的加工制造和在车架上的装配要点。     

汽车仪表板设计及制造

概述汽车仪表板的分类、使用要求及其总布置设计和造型设计;简单介绍其制造常用的工艺及材料。     

Optimal preview game theory approach to vehicle stability controller design

Dynamic game theory brings together different features that are keys to many situations in control design: optimisation behaviour, the presence of multiple agents/players, enduring consequences of decisions and robustness with respect to variability in the environment, etc. In the presented methodology, vehicle stability is represented by a cooperative dynamic/difference game such that its two agents (players), namely the driver and the direct yaw controller (DYC), are working together to provide more stability to the vehicle system. While the driver provides the steering wheel control, the DYC control algorithm is obtained by the Nash game theory to ensure optimal performance as well as robustness to disturbances. The common two-degrees-of-freedom vehicle-handling performance model is put into discrete form to develop the game equations of motion. To evaluate the developed control algorithm, CarSim with its built-in nonlinear vehicle model along with the Pacejka tire model is used. The control algorithm is evaluated for a lane change manoeuvre, and the optimal set of steering angle and corrective yaw moment is calculated and fed to the test vehicle. Simulation results show that the optimal preview control algorithm can significantly reduce lateral velocity, yaw rate, and roll angle, which all contribute to enhancing vehicle stability.     

Optimisation of lateral car dynamics taking into account parameter uncertainties

Simulation studies on an active all-wheel-steering car show that disturbance of vehicle parameters have high influence on lateral car dynamics. This motivates the need of robust design against such parameter uncertainties. A specific parametrisation is established combining deterministic, velocity-dependent steering control parameters with partly uncertain, velocity-independent vehicle parameters for simultaneous use in a numerical optimisation process. Model-based objectives are formulated and summarised in a multi-objective optimisation problem where especially the lateral steady-state behaviour is improved by an adaption strategy based on measurable uncertainties. The normally distributed uncertainties are generated by optimal Latin hypercube sampling and a response surface based strategy helps to cut down time consuming model evaluations which offers the possibility to use a genetic optimisation algorithm. Optimisation results are discussed in different criterion spaces and the achieved improvements confirm the validity of the proposed procedure.