用于模拟螺旋桨负载的双馈电机矢量控制研究

螺旋桨负载模拟是舰船电力推进系统中的重要研究内容.文中利用双馈电机四象限运行以及通过转子侧控制能降低变频器容量的特性,提出了双馈电机能量反馈系统模拟螺旋桨负载特性的方案.采用定子磁链定向的矢量控制策略,利用MATLAB/SIMULINK建立双馈电机模型和控制系统模型,实现不同工况下的稳态和动态特性模拟.仿真结果表明,转矩响应迅速、准确、稳定,采用矢量控制的双馈电机能量回馈系统具有良好的四象限负载特性模拟性能.     

基于唯一标识的ATP车载设备编码方案研究

设备唯一标识是实现ATP车载设备信息化管理和智能维修的前提.在分析国家标准和铁路标准对于设备唯一标识编码的基本原则和特点的基础上,结合ATP设备全路频繁流转的实际需求,提出了适用不同类型的ATP车载设备全路通用唯一标识编码方案.现场试验结果表明,该方案可推广应用于ATP车载设备的全生命周期追踪管理和日常运维.     

用Petri网对轨道区段和列车的建模研究

应用Petri网理论对轨道区段和列车的运行进行建模,为行车指挥提供了一个系统模拟和仿真的框架.作者在国内首次将Petri网应用于行车指挥自动化的研究,为列车的运行调整提供了列车及轨道区段的模型.     

全流式不透光烟度计的原理及应用

本文介绍了使用全流式不透光烟度检测仪器结合国际GB19758—2005对摩托车及轻便摩托车排放烟度进行测试的方法,介绍了烟度计的设计原理及性能特点。     

列车收缩管吸能防爬器耐撞性研究

为提升列车车辆在偏心碰撞和倾斜碰撞场景下列车车辆的耐撞性,提出一种收缩管吸能防爬器.该吸能结构在碰撞过程中,其收缩吸能管和吸能座圆锥面产生摩擦作用,收缩吸能管产生径向收缩变形吸收冲击动能,提升非正心碰撞场景下列车吸能结构的吸能特性.采用准静态拉伸试验得到吸能管材料的本构模型,并通过台车冲击试验验证所建立有限元模型的有效...     

Study on the form factor and full-scale ship resistance prediction method

To consider the resistance component due to hull geometry, the International Towing Tank Conference (ITTC) adopted the resistance test method in 1978, introducing the form factor concept with two basic assumptions, i.e., the form factor of a model ship is the same as that of a full-scale ship and the form factor is independent of ship speed. However, it is not only very difficult to determine the form factor using the ITTC ’78 method, but also there have been questions regarding the basic assumptions. Therefore, the authors carried out three basic studies on the form factor concept and proposed a new extrapolation procedure for the prediction of full-scale ship resistance performance. The validity of the proposed procedure is being investigated by comparing sea trial and model test results. The results of this investigation will be presented in the near future.     

基于Profibus-DP的西门子PLC与伟肯变频器通讯的实现

本文构建了由PC机、PLC、变频器组成的基于Profibus-DP总线的控制系统。文中分析了变频器通讯的相关参数设置及Profibus-DP通讯协议,利用Step-7和NC-Drive等软件开发实现了西门子S7-300PLC与伟肯变频器的实时通讯,同时也给出了相关组态流程及源程序。试验表明系统运行稳定、可靠。     

基于Revit的铁路线路三维信息平台开发

智能高铁是我国高速铁路发展的趋势,BIM技术融合智能化、信息化等手段,可实现铁路项目的全生命周期管理,提高管理水平和工作效率。根据BIM技术特点,基于Autodesk Revit建立铁路线路三维信息平台,为铁路项目信息化管理提供参考。首先,利用PowerCivil并根据线路平、纵断面等资料,生成线路中心线三维线形,为后续线路三维信息模型建立提供基础条件;随后,将线路中心线三维线形导入Revit平台,利用二维构筑物图纸创建各种构筑物族,再通过Dynamo编写命令将各种构筑物族沿线路里程布置,从而完成线路三维信息平台的构建。研究发现:三维信息平台可满足铁路线路模型三维可视化要求,并将铁路线路设计、施工、运维各阶段的信息进行融合,为铁路项目信息化管理搭建可操作的平台基础。     

浅析公路特殊路段路基防护与加固

论述公路路基一般防护与加固原则和处理措施,重点对滨河路基,风沙路基防护要求进行了介绍。     

Hybrid model for prediction of bus arrival times at next station

Effective prediction of bus arrival times is important to advanced traveler information systems (ATIS). Here a hybrid model, based on support vector machine (SVM) and Kalman filtering technique, is presented to predict bus arrival times. In the model, the SVM model predicts the baseline travel times on the basic of historical trips occurring data at given time‐of‐day, weather conditions, route segment, the travel times on the current segment, and the latest travel times on the predicted segment; the Kalman filtering‐based dynamic algorithm uses the latest bus arrival information, together with estimated baseline travel times, to predict arrival times at the next point. The predicted bus arrival times are examined by data of bus no. 7 in a satellite town of Dalian in China. Results show that the hybrid model proposed in this paper is feasible and applicable in bus arrival time forecasting area, and generally provides better performance than artificial neural network (ANN)–based methods. Copyright © 2010 John Wiley & Sons, Ltd.