振动减速带的速度控制效果研究

车速是影响道路交通安全的一个重要因素,提高速度控制技术的功效,对于改善道路安全性具有重要的意义。文章通过对振动减速带的车辆速度进行观测和分析,评价了速度控制设施的减速效果。     

一种特殊工况下动车组滑行问题分析和对策研究

通过对运营列车停车情况的分析,从停车原因、速度变化过程、轮轴之间速度差异等几个方面,深入论述了滑行现象产生及速度采集不均衡对行车控制的影响,提出车辆防滑控制、速度均衡优化的应对策略,为有效解决此类问题提供重要参考。     

Dynamic optimization of ship energy efficiency considering time-varying environmental factors

Nowadays, optimization of ship energy efficiency attracts increasing attention in order to meet the requirement for energy conservation and emission reduction. Ship operation energy efficiency is significantly influenced by environmental factors such as wind speed and direction, water speed and depth. Owing to inherent time-variety and uncertainty associated with these various factors, it is very difficult to determine optimal sailing speeds accurately for different legs of the whole route using traditional static optimization methods, especially when the weather conditions change frequently over the length of a ship route. Therefore, in this paper, a novel dynamic optimization method adopting the model predictive control (MPC) strategy is proposed to optimize ship energy efficiency accounting for these time-varying environmental factors. Firstly, the dynamic optimization model of ship energy efficiency considering time-varying environmental factors and the nonlinear system model of ship energy efficiency are established. On this basis, the control algorithm and controller for the dynamic optimization of ship energy efficiency (DOSEE) are designed. Finally, a case study is carried out to demonstrate the validity of this optimization method. The results indicate that the optimal sailing speeds at different time steps could be determined through the dynamic optimization method. This method can improve ship energy efficiency and reduce CO₂ emissions effectively.     

Contrasting the direct use of data from traffic radars and video-cameras with traffic simulation in the estimation of road emissions and PM hotspot analysis

This study investigates the effect of traffic volume and speed data on the simulation of vehicle emissions and hotspot analysis. Data from a microwave radar and video cameras were first used directly for emission modelling. They were then used as input to a traffic simulation model whereby vehicle drive cycles were extracted to estimate emissions. To reach this objective, hourly traffic data were collected from three periods including morning peak (6–9 am), midday (11–2 pm), and afternoon peak (3–6 pm) on a weekday (June 23, 2016) along a high-volume corridor in Toronto, Canada. Traffic volumes were detected by a single radar and two video cameras operated by the Southern Ontario Centre for Atmospheric Aerosol Research. Traffic volume and composition derived from the radar had lower accuracy than the video camera data and the radar performance varied by lane exhibiting poorer performance in the remote lanes. Radar speeds collected at a single point on the corridor had higher variability than simulated traffic speeds, and average speeds were closer after model calibration. Traffic emissions of nitrogen oxides (NOx) and particulate matter (PM₁₀ and PM_2.5) were estimated using radar data as well as using simulated traffic based on various speed aggregation methods. Our results illustrate the range of emission estimates (NO_x: 4.0–27.0 g; PM₁₀: 0.3–4.8 g; PM_2.5: 0.2–1.3 g) for the corridor. The estimates based on radar speeds were at least three times lower than emissions derived from simulated vehicle trajectories. Finally, the PM₁₀ and PM_2.5 near-road concentrations derived from emissions based on simulated speeds were two or three times higher than concentrations based on emissions derived using radar data. Our findings are relevant for project-level emission inventories and PM hot-spot analysis; caution must be exercised when using raw radar data for emission modeling purposes.     

Explaining shipping company participation in voluntary vessel emission reduction programs

Ports are under increasing pressures to increase sustainability and reduce the local and global emissions impacts associated with their operations. Due to limits on their jurisdictional authority, ports may design effective voluntary programs and appropriately motivate participation from global shipping companies that visit their ports. This paper investigates the success of the Vessel Speed Reduction Program at the Ports of Los Angeles and Long Beach and uses qualitative methods to analyze the factors that contributed to the success of the program at reducing local air quality pollutants. In particular, why did individual private firms participate in a non-required, voluntary effort? This research found that external pressures such as community concerns about emissions and regulatory threats are important to motivating voluntary behavior and may even be more important than financial incentives. Furthermore, simplicity of program design, clear goals and presence of a monitoring mechanism are important in influencing participation. These findings broaden our understanding of the business strategy behind slow steaming and its applicability as an operational practice as much work to date is focused on how fuel prices and financial incentives influence the choice for shipping companies to slow their speeds. While the VSR program led to significant emission reductions, an additional lesson for voluntary programs is the need for them to evolve and strive for continuous improvement.     

大型油船航速估算方法

对现有的船舶航速估算方法分析比较，提出了大型油船的航速估算方法。其中有效功率估算是根据上海船研所肥大船系试验图谱和实船试验资料经分析、修正得出，与荷兰Ｈｏｌｔｒｏｐ法、大连造船厂法比较，本文方法均方差最小，估算值与试验值最接近；自航因子估算以ＳＳＰＡ大油轮系列自航试验资料为基础，用上海船研所大量肥大船模型自航试验数据修正得出。     

磁悬浮列车定位测速及数据传输方法研究

分析了磁悬浮列车信号通信系统的特点，由于磁悬浮列车无法使用轨道电路，着重分析了微波和轨间电缆在定位测速及数据传输中的各种应用方法，给出了估算公式，比较了各种方法的优缺点。在以上分析的基础上，结合我国磁悬浮列车的发展情况，提出了适合我国现阶段的定位测速及数据传输的方案，并介绍了相关试验结果。     

基于模糊神经网络的驼峰推送速度控制研究

对影响驼峰机车推送速度的各种因素进行了探讨,将模糊神经网络理论引入到驼峰变速推峰系统中,结合神经网络和模糊控制的各自优点,将专家或熟练操作人员的控制策略转换为控制功能函数,利用神经网络自学习、自校正的能力调整、修改模糊控制规则,从而实现对推送速度的优化控制。     

高速铁路车辆系统电磁兼容性能分析与测量

分析高速铁路车辆系统复杂的电磁环境,针对供电系统、列控车载设备(系统)、无线电通信与调度系统中存在的典型电磁干扰现象,分别对低压电源、速度传感器、无线通信设备的电磁兼容问题进行分析,提出相应的解决方法,为建立完善的高速铁路车辆系统电磁兼容标准提供依据。     

重载货车轴重与速度匹配关系研究

基于重载货车轨道耦合动力学模型,采用机车车辆与线路最佳匹配设计方法,进行货车轴重与速度的匹配研究.结果表明:25,27,30和40t轴重重载货车容许通过轨道低接头的速度应分别小于110,100,90和60km·h-1;40t轴重重载货车以60km·h-1速度在直线线路上运行时,其轮轨垂向力为249.6kN,非常接近英国铁路250kN轮轨垂向力的限值;在我国现有以60kg·m-1轨为主的干线铁路上开行30和40t轴重重载货车,对轨道结构的破坏比现有低轴重货车严重得多,但开行27t轴重重载货车是可行的;40t轴重重载货车在600m半径的曲线轨道上以40～120km·h-1速度运行时,轮轨垂向力最大值超过了英国铁路的250kN轮轨垂向力限值,轮轨横向力最大值非常接近我国《铁道车辆动力学性能评定及试验鉴定规范》所规定的77.80kN容许限值,另外轮轨磨耗功非常大,因此40t轴重重载货车还不能直接应用于我国现有60kg·m-1钢轨的轨道.