盾构刀盘驱动多电机同步控制策略研究

为了保障盾构刀盘驱动系统能够稳定运行,刀盘驱动电机之间的同步性能是一个关键因素。针对盾构电机数量多、结构复杂的特点,分析主从控制、并行同步控制和几种耦合控制在盾构驱动电机控制应用中的优缺点,说明并行同步在应用中的合理性;设计一种模糊PID智能控制算法,提出模糊PID控制器与并行同步控制结构相结合的盾构刀盘驱动多电机同步控制策略,应用Matlab/simulink进行建模仿真,对该控制策略和常规的PI控制进行仿真对比。结果证明:所提出的控制策略的动态响应快、实时性能好,在相同的负载突变状况下,该方法具有更强的鲁棒性,能更好地使多电机以设定速度同步运行。     

Multi-resolution modeling and simulation for urban rail transit network planningEI北大核心

Research purposes: Simulation technology plays an important role in the urban rail transit network planning and analysis. With the enlargement of the urban rail network scale, the complexity and difficulty in the development of simulation system for urban rail transit network planning increase. To develop the simulation system with high efficiency, an approach to multi-resolution modeling and simulation of urban rail transit system is presented. Research conclusions: (1) An approach to build a multi-resolution simulation system of urban rail transit is presented, by building and integrating transit network architecture models and passenger models in different resolutions. (2) Ahierarchical model of rail transit network topology is built to resolve the problem of spatial consistency in multi-resolution modeling. (3) A polymerization based station simulation model is built to resolve the problem of state consistency. (4) To meet the needs of extensibility and flexibility of the simulation system, an agent-based integration method is applied to develop the simulation system of urbanrail transit network. (5) Arealized example on the application of the simulation model is introduced, which is used to analyze and evaluate a transit network planning.     

基于Freescale单片机的新型自适应电控天然气喷嘴驱动设计

设计出一种采用输出脉宽调制(PWM)信号来控制电控天然气喷嘴喷射的自适应式新型驱动电路,实现了高压打通低压保持喷射,解决了传统驱动方式喷嘴发热过大的问题,提高了喷射的稳定性和喷嘴的使用寿命。结合仿真软件AMESim进行了仿真实验。将计算流量和实验流量进行对比,验证了自适应式驱动方式的正确性。     

Evaluating CO2 emissions, cost, and service quality trade-offs in an urban delivery system case study

Growing pressure to limit greenhouse gas emissions is changing the way businesses operate. This paper presents the trade-offs between cost, service quality (represented by time window guarantees), and emissions of an urban pickup and delivery system under these changing pressures. A model, developed by the authors in ArcGIS, is used to evaluate these trade-offs for a specific case study involving a real fleet with specific operational characteristics. The problem is modeled as an emissions minimization vehicle routing problem with time windows. Analyses of different external policies and internal operational changes provide insight into the impact of these changes on cost, service quality, and emissions. Specific consideration of the influence of time windows, customer density, and vehicle choice are included.The results show a stable relationship between monetary cost and kilograms of CO₂, with each kilogram of CO₂ associated with a $3.50 increase in cost, illustrating the influence of fuel use on both cost and emissions. In addition, customer density and time window length are strongly correlated with monetary cost and kilograms of CO₂ per order. The addition of 80 customers or extending the time window 100 minutes would save approximately $3.50 and 1 kilogram of CO₂ per order. Lastly, the evaluation of four different fleets illustrates significant environmental and monetary gains can be achieved through the use of hybrid vehicles.The results demonstrate there is not a trade-off between CO₂ emissions and cost, but that these two metrics trend together. This suggests the most effective way to encourage fleet operators to limit emissions is to increase the cost of fuel or CO₂ production, as this is consistent with current incentives that exist to reduce cost, and therefore emissions.     

电控单体泵喷油电磁阀驱动控制电路设计

根据大功率柴油机电控单体泵系统对驱动的要求,以Peak & Hold驱动为基础,给出了电路总体设计方案,完成了升压驱动电路设计.在大功率电控单体泵上进行验证,试验结果表明,该升压驱动电路最小工作间隔5 ms,电磁阀高压峰值电流达到20 A,维持电流15 A,开启响应时间200μs以内,低压维持电流8 A,满足了电控单体...     

六相永磁同步电动机串联驱动系统的研究

以两台双Y移30°六相永磁同步电动机(PMSM)为例,建立起一种新颖的电机串联驱动系统的仿真模型.在这种新型驱动系统中,两台六相永磁同步电动机的定子绕组通过恰当的相序调整串联起来,由一台六相电压源逆变器供电,可以实现两台电机独立的矢量控制.在Matlab/Simulink环境中对电机的变载运行进行了仿真,仿真结果验证了...     

汽车滚装船艉部布置特征

与普通运输船相比,汽车滚装船船型特征明显,船身高大,有多层甲板。船体采用中段肥胖,艏、艉部线型瘦削,特别是艉部机舱等的布置,外形采用方艉,设有宽大的艉门兼作跳板,方便车辆进出。     

An integrated real-time traffic signal system for transit signal priority,incident detection and congestion management

This paper presents a traffic control system that can work standalone to handle various boundary conditions of the recurrent, non-recurrent congestion, transit signal priority and downstream blockage conditions to improve the overall traffic network vehicular productivity and efficiency. The control system uses field detectors’ data to determine the boundary conditions of all incoming and exit links. The developed system is interfaced with CORSIM micro-simulation for rigorous evaluations with different types of signal phase settings. The comparative performance of this control logic is quite satisfactory for some of the most frequently used phase settings in the network with a high number of junctions under highly congested conditions.     

城市中心区地铁联络线规划设计方案优化研究——以广州地铁11、13号线天河公园换乘站联络线为例

广州地铁11、13号线天河公园站地处广州市中心区,密集的建筑物、复杂的设计施工条件及较高的环境要求很大程度地限制了广州地铁11、13号线天河公园站联络线规划设计自由度。在分析原联络线方案存在问题基础上,提出采用大半径曲线使之适应盾构法施工条件和采用小半径曲线使之降低矿山法涌水涌砂施工风险两个优化联络线方案的思路,并从联络线条件、对周边环境的影响、工程风险和工程投资等方面进行比选优化研究,曲线半径为200 m的联络线方案因具有较好的技术经济效益而被推荐。研究方法及结论对高环境要求下的城市中心区地铁联络线的规划设计具有借鉴意义。最后总结城市中心区地铁联络线规划设计中应综合考虑的因素,确保最终推荐的工程方案合理可行。     

Objective correlates and determinants of bicycle commuting propensity in an urban environment

ObjectiveBicycle use for commuting is being encouraged not only to address physical inactivity, but also vehicular congestion, air pollution and climate change. The current study aimed to ascertain the urban environmental correlates and determinants of bicycle use for commuting (bicycle commuting) among the working or studying population in Barcelona, Spain.MethodsAdults (n = 769; 52% females) recruited whilst commuting within Barcelona (Spain) responded to a comprehensive telephone survey concerning their travel behaviour. Based upon responses collected from June 2011 to May 2012, participants were categorised into four groups: frequent bicyclists, infrequent bicyclists, willing non-bicyclists, and unwilling non-bicyclists. The determinants of frequency and willingness (propensity) to commute by bicycle were assessed by multinomial logistic regression models adjusted for potential confounders and covariates.ResultsThe number of public bicycle stations surrounding the home address and amount of greenness surrounding the work/study address were significant positive determinants of bicycle commuting propensity. On the other hand, the number of public transport stations surrounding the home address and elevation of the work/study address were significant negative determinants of bicycle commuting propensity. Individual age, education level, gender, nationality, physical activity level and commute distance significantly affected this propensity.ConclusionGreater availability of public bicycle stations and higher levels of urban greenness may increase bicycle use by adults commuting within a city such as Barcelona, Spain. Electrically-assisted public bicycles may address the challenge of elevation, making this system a more competitive mode against traditional motorised public transport.