无线机车信号系统的开发与应用研究

介绍了无线机车信号系统的结构、原理及功能，并与通用机车信号对比，描述了无线机车信号系统的特点和优势。分析了系统的可靠性和故障一安全性。探讨了无线机车信号的应用方案。     

Control of a hydraulically actuated continuously variable transmission

Vehicular drivelines with hierarchical powertrain control require good component controller tracking, enabling the main controller to reach the desired goals. This paper focuses on the development of a transmission ratio controller for a hydraulically actuated metal push-belt continuously variable transmission (CVT), using models for the mechanical and the hydraulic part of the CVT. The controller consists of an anti-windup PID feedback part with linearizing weighting and a setpoint feedforward. Physical constraints on the system, especially with respect to the hydraulic pressures, are accounted for using a feedforward part to eliminate their undesired effects on the ratio. The total ratio controller guarantees that one clamping pressure setpoint is minimal, avoiding belt slip, while the other is raised above the minimum level to enable shifting. This approach has potential for improving the efficiency of the CVT, compared to non-model based ratio controllers. Vehicle experiments show that adequate tracking is obtained together with good robustness against actuator saturation. The largest deviations from the ratio setpoint are caused by actuator pressure saturation. It is further revealed that all feedforward and compensator terms in the controller have a beneficial effect on minimizing the tracking error.     

相对标高和绝对标高立模法在虎跳门大桥施工中的应用

为消除温度效应对主梁挠度变化的复杂影响,在虎跳门大桥的施工过程中,针对结构不同的悬臂状态和温度情况,综合采用了绝对标高和相对标高立模法,在实施过程中取得了较好的效果。     

GPS全球定位系统中卫星覆盖区的探讨

主要讨论单颗GPS卫星的覆盖区,包括有、无仰角两种情况,对有一定的仰角的卫星覆盖区的计算采用了更简洁的方法,指出《航海仪器》中出现的错误并进行了更正。     

新技术应用于厦门环岛路A标工程

针对新技术在厦门环岛路A标工程的成功应用,介绍了箱梁—墩柱—灌注桩竖向预应力结构体系的施工技术、后张法预应力孔道真空压浆技术、海中低标高桥梁的现浇箱梁的设计与施工技术等。工程的实践证明:各项新技术、新材料的应用是成功的。为今后类似的工程施工或单项技术工艺的应用提供了借鉴。     

汽车动力传动系统匹配研究

汽车动力性、经济性的好坏很大程度上取决于汽车动力传动系统合理匹配的程度,发动机与传动系的合理匹配将显著降低汽车的燃油消耗并可获得较好的动力性.为改善发动机与传动系参数匹配不当的现状,本文以传动系参数给定,优选发动机参数为方向,对汽车动力传动系统进行了匹配研究.结果表明,通过优化匹配,汽车的动力性、经济性均得到一定的提高.     

数字视频传输系统的应用

MSTP采用共享环的形式实现带宽共享,可大大提高传输系统的带宽利用率.采用基于MSTP的MPEG-2的视频传输图像清晰、延时小,满足地铁高质量监控的要求.     

港口计算机监控系统的架构与功能

介绍CMS的构成、数据采集和传输方式,分析CMS的功能要求.一个功能完备的CMS系统至少应具备实时动态画面监控、故障诊断与排除、在线编程、实时趋势和历史趋势、数据库、统计报表、Web浏览等功能.     

吉林省高速公路专用通信网综述

吉林省高速公路专用通信网络主要由长春至四平和长春至吉林两条高速公路上的通信系统构成 ,设置通信中心、通信分中心、通信站等几层管理机构 ,包括干线通信系统、传输系统、通信系统等几大部分。干线通信系统主要采用光缆传输 ,辅以电缆 ,光、电缆在公路中央隔离带内的预埋管道中敷设 ,管道分四孔波纹塑料管道和硅管两种 ,分别用于长平、长吉两条高速公路。传输系统为适应高速公路通信特点 ,采用 PDH光电综合复用设备 ,具有能自动倒换的 1B1H码 ,各通信中心、通信分中心、通信站配置光端机 (光中继机 ) ,PCM等设备 ,以满足光传输要求。通信系统由业务电话、紧急电话、移动电话系统组成。业务电话系统采用 MD110数字程控用户交换机 ,全网共配置 6部 ,用以高速公路上沿线各部门内部业务通信和长途通信。在两条高速公路两侧配置了不同厂家的紧急电话 ,全网共设 10 8对分机。高速公路的移动通信系统采用 80 0 MHz的集群移动通信设备 ,用以满足施工建设、巡逻、救援和维护等移动工作人员的日常需求     

Optimisation of full-toroidal continuously variable transmission in conjunction with fixed ratio mechanism using particle swarm optimisation

The aim of this research is the optimisation of full-toroidal continuously variable transmission (CVT) in conjunction with the fixed ratio (FR) mechanism, while the optimisation objective is to minimise fuel consumption (FC) of the vehicle in the new European driving cycle. After the dynamic analysis of the power train, a computer model is developed to simulate contact between CVT elements and consequently calculate its efficiency. Then an algorithm is presented to calculate FC of the vehicle in the driving cycle. Then, an optimisation using particle swarm optimisation on the CVT geometry and FR mechanism (which is embedded between CVT and final drive) is carried out to minimise FC. It is found that by utilisation of the optimised CVT; FC will be about 11% and 8% lower, compared with the application of a five-speed manual transmission and conventional CVT, respectively. Finally, effects of the roller tilt angle and oil temperature on the FC are investigated.