Robust control of anti-lock brake system

A robust control algorithm for an anti-lock brake system is proposed. The method used is based on static-state feedback of longitudinal slip and does not involve controller scheduling with changing vehicle speed or road adhesion coefficient estimation. An improvement involving scheduling of longitudinal slip reference with longitudinal acceleration measurement is included. Electromechanical braking actuators are used in simulations, and the algorithm used in this study is shown to have high performance on roads with constant and varying adhesion coefficients, displaying nice robustness properties against large vehicle speed and road adhesion coefficient variations. Guidelines are provided for tuning controller gains to cope with unknown actuator delay and measurement noise.     

Locating charging infrastructure for electric buses in Stockholm

Charging infrastructure requirements are being largely debated in the context of urban energy planning for transport electrification. As electric vehicles are gaining momentum, the issue of locating and securing the availability, efficiency and effectiveness of charging infrastructure becomes a complex question that needs to be addressed. This paper presents the structure and application of a model developed for optimizing the distribution of charging infrastructure for electric buses in the urban context, and tests the model for the bus network of Stockholm. The major public bus transport hubs connecting to the train and subway system show the highest concentration of locations chosen by the model for charging station installation. The costs estimated are within an expected range when comparing to the annual bus public transport costs in Stockholm. The model could be adapted for various urban contexts to promptly assist in the transition to fossil-free bus transport. The total costs for the operation of a partially electrified bus system in both optimization cases considered (cost and energy) differ only marginally from the costs for a 100% biodiesel system. This indicates that lower fuel costs for electric buses can balance the high investment costs incurred in building charging infrastructure, while achieving a reduction of up to 51% in emissions and up to 34% in energy use in the bus fleet.     

Reliable route guidance: A case study from Chicago

Reliable route guidance can be obtained by solving the reliable a priori shortest path problem, which finds paths that maximize the probability of arriving on time. The goal of this paper is to demonstrate the benefits and applicability of such route guidance using a case study. An adaptive discretization scheme is first proposed to improve the efficiency in computing convolution, a time-consuming step used in the reliable routing algorithm to obtain path travel time distributions. Methods to construct link travel time distributions from real data in the case study are then discussed. Particularly, the travel time distributions on arterial streets are estimated from linear regression models calibrated from expressway data. Numerical experiments demonstrate that optimal paths are substantially affected by the reliability requirement in rush hours, and that reliable route guidance could generate up to 5-15% of travel time savings. The study also verifies that existing algorithms can solve large-scale problems within a reasonable amount of time.     

新颖船用CWJK23型遥控系统

ＣＷＪＫ２３型船用柴油机电气混和式遥控系统具有操纵主机的全部逻辑功能。系统采用模块化设计，并应用线性积分电路与精密比例压力调节阀ＭＰＰＥ－２匹配，驱动主机执行机构进行调速，大大缩短了气控管系，使实船安装调试简便，参数调整容易，配机特性好，适用于大多数采用气控操作的柴油机。     

回归分析方法在VTS预测研究中的应用

该文将数理统计中的回归分析方法应用到ＶＴＳ预测研究中，其预测结果有较高的精度，是基础理论应用于工程实际的有益实践，为ＶＴＳ规划研究提供了一种实用的预测方法。     

天文定位的最优估计方法及其应用

论述了天文定位的最优估计方法及其精度。六分仪观测值与依赖于ＧＭＴ和推算船位的该值的预测值之差，与来自卡尔曼滤波器增益阵的ＫΦ和Ｋλ相乘，可以得到推算船位与最优估计船位的差值ＤΦ和Ｄλ。它们与推算船位的线性组合可以实时地给出最佳船位，即使只有一次观测亦是这样。最优估计方法被应用于作者研制的ＨＸ－１１１３天文导航仪和ＧＰＥＳ１型电子六分仪，海上试用的结果表明，该方法不仅定位方便，而且精度高，中午附近定位误差可达１ｎｍｉｌｅ之内。     

Fuzzy and adaptive fuzzy control for the automobiles' active suspension system

Two typical criteria for good vehicle suspension performance are their ability to provide good road handling and increased passenger comfort. The main disturbance affecting these two criteria is terrain irregularities. Active suspension control systems reduce these undesirable effects by isolating car body motion from vibrations at the wheels. This paper describes fuzzy and adaptive fuzzy control (AFC) schemes for the automobile active suspension system (ASS). The design objective is to provide smooth vertical motion so as to achieve the road holding and riding comfort over a wide range of road profiles. The efficacy of the proposed control schemes is demonstrated via simulations. With respect to the optimal linear quadratic regulator (LQR), it is shown that superior results have been achieved by the AFC.     

大型散货船结构节点疲劳寿命的分析计算

根据应力幅长期分布的Ｗｅｉｂｕｌｌ分布假设及结构材料疲劳的Ｓ－Ｎ曲线和线性累积损伤Ｍｉｎｅｒ准则，使用数值分析与解析相结合的混合法对３４０００ＤＷＴ大潮型散货船结构进行了分析计算，结果令人满意，证实本文介绍的方法解决船体结构在疲劳载荷作用下疲劳寿命估算的实用方法。     

地铁车辆直线电机气隙在线检测系统结构

气隙在线检测系统是集数据采集、分析、处理与实时通信于一体的计算机测量系统。作为直线电机地铁车辆的维护设备之一,当车辆通过系统时,其可以实现自动辨别车号、计算车速、记录轴数、测量气隙高度等功能,并通过计算机内部设备的判别模型,对超限数据进行报警。     

合龙方案对多跨连续梁桥施工监控的影响分析

多跨连续梁的合龙顺序对结构成桥累计位移和内力有较大影响,以1座(48+4×80+48)m预应力混凝土连续梁桥为例,根据不同的合龙方案确定3种工况,对不同工况下的桥梁结构建立不同结构体系转换的施工阶段分析有限元模型,分析合龙顺序及合龙期间的预应力张拉阶段对施工阶段的预拱度及成桥内力的影响,对比分析多跨连续梁桥合龙口两端产生较大位移差的原因。提出多跨连续梁桥线形监控难度的主要影响因素为累计位移最大值和合龙口两端的累计位移差。结果表明,合龙顺序对梁体施工中的预拱度设置量影响较大,特别是不同结构体系下预应力张拉效应差别较大,合理的合龙顺序和分批分阶段张拉预应力可降低施工过程中线形监控的难度,根据分析结果提出合理的合龙顺序建议。