并联式混合动力汽车能量管理的马尔可夫决策

为研究同轴并联式混合动力汽车的能量管理策略,建立了同轴并联式动力系统动态方程,分析了转矩需求无后效性的马尔可夫特性.在维持电池容量不变的条件下,以燃油消耗最小为优化目标,采用马尔可夫决策实施能量管理策略,并采用策略迭代方法求解了马尔可夫能量管理的转矩决策过程,在J1015工况和昆明工况进行了仿真,实现了能量管理的在线实施.结果表明,与基于动态规划的能量管理策略相比,马尔可夫决策的能量管理策略能在线实施,且电池容量变化更为平稳;在燃料消耗方面是全局次优的,在J1015行驶工况下100 km燃油消耗增加了1.32 L,在昆明行驶工况下100 km燃油消耗增加了1.59 L.      

达成铁路悦来场滑坡整治设计及施工的体会

为作者参与悦来场滑坡整治工程设计与施工全过程中的心得体会。     

门机变幅机构润滑油温度的Fuzzy-PI控制

介绍港口门机变幅机构润滑油温度的Fuzzy -PI控制的基本原理 ,以及Fuzzy -PI控制器的设计过程 ,实践证明这种控制器具有过渡时间短、超调量小等特点 ,应用效果良好     

加强整体化层对T梁受力影响的试验评估

某高速公路装配式T梁桥桥面板破损严重,后采用加铺整体化层的办法对桥面板进行了加强;加铺在提高了梁体的刚度和整体受力性能的同时,也增加了桥跨的恒载,使T梁的工作状态发生了改变.通过荷载试验的方式测试加铺前、后结构的反应,对加铺后T梁的实际工作状态进行了评估和分析.     

基于风险三维结构的大型油轮监管集成

大型油轮运输属于危险品运输,其生产作业具有高危特性.在大型油轮航行和生产作业全过程中会面临从宏观到微观的多层次风险,对通航安全构成潜在威胁.借鉴某三维结构和集成企业工程思想构建大型油轮风险集成管理的三维结构模型,将多层次的风险管理归并到三个维度(功能域、时间域及对象域),以风险三维结构为基础,探讨风险管理集成的主要构成,提出了大型油轮风险管理集成的基本模型和系统监管模式,为相关海事部门监管大型油轮航行及生产作业提供参考依据与决策支持.     

Investigating the effect of travel time variability on drivers' route choice decisions in Shanghai,China

Abstract

This paper investigates the effect of travel time variability on drivers' route choice behavior in the context of Shanghai, China. A stated preference survey is conducted to collect drivers' hypothetical choice between two alternative routes with designated unequal travel time and travel time variability. A binary choice model is developed to quantify trade-offs between travel time and travel time variability across various types of drivers. In the model, travel time and travel time variability are, respectively, measured by expectation and standard deviation of random travel time. The model shows that travel time and travel time variability on a route exert similarly negative effects on drivers' route choice behavior. In particular, it is found that middle-age drivers are more sensitive to travel time variability and less likely to choose a route with travel time uncertainty than younger and elder drivers. In addition, it is shown that taxi drivers are more sensitive to travel time and more inclined to choose a route with less travel time. Drivers with rich driving experience are less likely to choose a route with travel time uncertainty.     

基于轮胎磨损的悬架与转向系统硬点优化

基于轮胎磨损理论,定量分析前轮定位参数和阿克曼误差对轮胎磨损的影响.在Adams/Car模块中建立前悬架与转向系模型,运用Insight模块进行灵敏度分析,选择合适硬点坐标拟合前轮定位参数和阿克曼误差的响应面函数.建立相关约束函数和目标函数,并运用Matlab软件进行硬点坐标优化.结果表明,车轮外倾角变化减少27.65％,前束角变化曲线变得更为合理,且阿克曼误差均方根值减少14.7％,有效减少了轮胎磨损.     

On the role played by turbulence closures in hull shape optimization at model and full scale

 The practical use of automated computational fluid dynamics (CFD)-based design tools in the ship-building industry requires powerful flow solvers which are able to take into account realistic geometries as well as complex physical phenomena, such as turbulence. A shape optimization tool is developed in this framework. A derivative-free optimizer, yielding both flexibility and robustness, is preferred to the classical gradient-based method, which is more difficult to implement and is still limited to only moderately complex problems. The flow solver included in the design procedure solves the incompressible Reynolds-averaged Navier–Stokes equations on unstructured grids using a finite-volume formulation involving several near-wall low-Reynolds-number turbulence models. The design tool is used to optimize the stern of a modern hull shape at model and full scale, with different purposes being considered. More precisely, the drag reduction and the homogenization of the flow in the wake are expected by controlling the longitudinal vortex generated. Our interest is particularly focused on the influence of turbulence modeling in the design process. The effects of a two-equation model based on the eddy-viscosity assumption and a second-order closure relying on the Reynolds stress transport equations are compared. Received: September 24, 2002 / Accepted: April 14, 2003 RID="*" Acknowledgment. The authors thank the scientific committee of CINES (project dmn2050) for the attribution of CPU time.     

轨道交通通信系统的传输技市比较

为了更好地推荐轨道交通领域对传输网络的建设方案,构建健壮、多业务、弹性的传送平台,提出构建弹性可重购(3R:Reconfigurable,Resilient,Reliable)、高效性价比、统一的多业务传递平台的解决方案.对主流传输技术进行了详细比较,认为弹性可重购3R多业务传送平台满足轨道交通分拆和延长分期建设的要求.展望了未来的承载网技术,分析和比较了MSTP(多业务传送平台)和IP传送平台.     

子结构组合系统分析中的分步计算法——用试验模态参数进行汽车整车动力学模型建模的探讨

本文应用子结构组合模态综合法,利用试验模态数据,在计算机上建立了一个包括汽车20Hz之前各阶弹性模态和刚体模态的整车动力学模型。为容纳尽可能多的模态数和测点数,提出了在模型计算过程中的分步计算法。