基于CAN总线的调距桨控制系统研究

可调螺距螺旋桨(简称调距桨CPP)是船舶推进系统的主要设备,调距桨能在所有工况下充分吸收主机的全功率,提高螺旋桨效率,并实现螺旋桨与主机转速的最佳匹配.它有良好的机动与操纵性能且易于实现遥控,在多种船舶上得到广泛应用.基于CAN总线的调距桨控制系统,结构简单,成本低,可靠性高,具有很好的推广价值.     

智能分布式驱动汽车路径跟踪/制动能量回收协同控制策略研究

为了解决智能分布式驱动汽车路径跟踪与制动能量回收系统间的协同控制难题,充分考虑分布式驱动汽车四轮扭矩独立可控在智能驾驶系统中的优势,设计适应不同路面附着条件的智能分布式驱动汽车转向、制动分层协同控制策略。上层控制器依据不同的路面类型设计差异化的多目标代价函数,以综合优化各工况下的控制目标。高附路面下,制定满足最大能量回收值的全局参考车速,在线优化路径跟踪指令,实现最优能量回收的同时减小系统运算负荷;低附路面下,优先考虑车辆的路径跟踪性能和行驶稳定性,在多目标代价函数中取消对全局参考车速的跟随要求,增设终端速度约束与能量回收项性能指标并减小能量回收项性能指标的权重系数。上层控制器基于模型预测控制方法对多目标代价函数进行滚动优化与预测求解,得到期望的前轮转角及4个车轮的总制动扭矩需求。下层控制器根据制动扭矩需求对四轮的液压制动扭矩和电机制动扭矩进行分配,最终完成整个复合制动过程。基于MATLAB/Simulink和CarSim软件,搭建控制器在环仿真平台,并在高附和低附路面条件下对所提出的策略进行试验验证。研究结果表明：高附路面下,所提出的控制策略在准确跟踪期望路径的同时相较固定比例制动力分配方法可提升2.7%的能量回收值并减少约0.02 s的单次计算时间;低附路面下,与使用高附控制策略相比,能够保证车辆的路径跟踪准确性与行驶稳定性,同时可提升7.8%的能量回收值;控制器在环试验结果证明了该协同控制策略对车辆性能提升的有效性。     

HEART AT SOUTH CHINA SEA

After accomplishing his mission of recovering the Yongxing Island,Li Jing Sen returned to Guangzhou on the naval ship Yong Xing.The beautiful scenes of the blue ocean,lush vegetation on the island,and flocks of seabirds kept appearing in his mind.The crew＇s next assignment was an anti-smuggling inspection at the Pear River Estuary. They stationed at Hu Men ships while they checked passing by for smuggling activity. Three months later, they received order to patrol the South China Sea. This assignment gave Li the opportunity to sail through the area. In addition to patrolling, the ship also brought supplies to soldiers garrisoned on the islands, and replacement personnel.     

浅析建筑废弃物在虹桥综合交通枢纽的应用

该文对虹桥综合交通枢纽市政配套工程固废利用试验段的实施进行了总结,提出了建筑渣土用于路基处理是可行的,但使用HEC固结建筑渣土时应加强对施工工艺的改进,使用水泥固结建筑渣土时应就近设置破碎拌和厂;同时,由于HEC/水泥固结建筑渣土的后期开裂性能未有进入研究,建议在道路基层中应谨慎使用。     

A programmable calculation procedure for number of traffic conflict points at highway intersections

Traffic movement conflict points at intersections are the points at which traffic movements intersect (including crossing, merging, and diverging). Numbers and distribution of different types of conflict points are used to evaluate intersection access management designs and safety performance. Traditionally, the determination of the numbers of conflict points for different traffic movements is based on manual methods, which causes the difficulty for computerized procedures to evaluate safety performance of different access management designs. Sometimes, a programmable calculation procedure may provide more effective solutions as compared with manual methods. This paper presents a programmable calculation procedure for the determination of the numbers of conflict points, which could be used as a basis for a computerized procedure. Concepts of virtual movement lanes and intersection quadrants are introduced to specify types of intersections, traffic lane configurations, and traffic movement regulations. Calculation models, based on such concepts, for traffic movement conflict points at signalized and unsignalized intersections can be obtained. In support of the procedure, case studies are presented in the paper. The procedure presented in the paper can be programmed into a computer program for the purpose of a computerized evaluation of intersection safety and design performance of different access management or control approaches. Copyright © 2012 John Wiley & Sons, Ltd.     

我国新旧饮用水水质标准变化与探讨

原生活饮用水卫生标准（GB5749-1985）执行时间已长达二十多年,现今已不再适合飞速发展的经济需要所要求的水质标准。同时,在饮用水安全方面也需随着社会的发展而适时调整旧的水质标准。该文对新、原旧两种水质标准从生物学、毒理学、放射性指标等方面进行比较,以增加人们对新标准的理解和认识。     

单箱多室波形钢腹板箱梁桥设计方法探讨

波形钢腹板箱梁桥应用于宽桥面时,为了保证抗剪,常常需要多道腹板,因而出现单箱多室波形钢腹板组合箱梁桥。然而,在建立单梁模型时,常用软件并不能准确模拟此种截面形式。为此,该文以单箱两室波形钢腹板三跨连续梁桥为例,建立梁格模型与简化的单梁模型进行对比分析,并通过实体模型验证这两种模型的适用性,为该类桥型的设计研究提供参考。     

船用小型汽轮机危急保安器特性分析

针对船用小型汽轮机常用的超速危急保安器结构特点，从偏心式飞锤、压紧弹簧及整个保安器三个方面对力学特性和运动特性进行了分析，获得了脱扣前、脱扣后及复位过程的特性，并得出了调整垫片厚度对脱扣转速的变化规律，可为汽轮机机组安全运行提供保障。     

Flexible feeder transit route design to enhance service accessibility in urban area

To improve the accessibility of transit system in urban areas, this paper presents a flexible feeder transit routing model that can serve irregular‐shaped networks. By integrating the cost efficiency of fixed‐route transit system and the flexibility of demand responsive transit system, the proposed model is capable of letting operating feeder busses temporarily deviate from their current route so as to serve the reported demand locations. With an objective of minimizing total bus travel time, a new operational mode is then proposed to allow busses to serve passengers on both street sides. In addition, when multiple feeder busses are operating in the target service area, the proposed model can provide an optimal plan to locate the nearest one to response to the demands. A three‐stage solution algorithm is also developed to yield meta‐optimal solutions to the problem in a reasonable amount of time by transforming the problem into a traveling salesman problem. Numerical studies have demonstrated the effectiveness of the proposed model as well as the heuristic solution approach. Copyright © 2015 John Wiley & Sons, Ltd.