Energy-saving operation approaches for urban rail transit systems

With the accelerated urbanization in China, passenger demand has dramatically increased in large cities, and traffic congestion has become serious in recent years. Developing public urban rail transit systems is an indispensable approach to overcome these problems. However, the high energy consumption of daily operations is an emerging issue due to increased rail transit networks and passenger demands. Thus, reducing the energy consumption and operational cost by using advanced optimization methodologies is an urgent task for operation managers. This work systematically introduces energy-saving approaches for urban rail transit systems in three aspects, namely, train speed profile optimization, utilization of regenerative energy, and integrated optimization of train timetable and speed profile. Future research directions in this field are also proposed to meet increasing passenger demands and network-based urban rail transit systems.     

Robust energy-efficient train speed profile optimization in a scenario-based position–time–speed network

Train speed profile optimization is an efficient approach to reducing energy consumption in urban rail transit systems. Different from most existing studies that assume deterministic parameters as model inputs, this paper proposes a robust energy-efficient train speed profile optimization approach by considering the uncertainty of train modeling parameters. Specifically, we first construct a scenario-based position–time–speed (PTS) network by considering resistance parameters as discrete scenario-based random variables. Then, a percentile reliability model is proposed to generate a robust train speed profile, by which the scenario-based energy consumption is less than the model objective value at \alpha confidence level. To solve the model efficiently, we present several algorithms to eliminate the infeasible nodes and arcs in the PTS network and propose a model reformulation strategy to transform the original model into an equivalent linear programming model. Lastly, on the basis of our field test data collected in Beijing metro Yizhuang line, a series of experiments are conducted to verify the effectiveness of the model and analyze the influences of parameter uncertainties on the generated train speed profile.     

Predictive Control Algorithm for Urban Rail Train Brake Control System Based on T-S Fuzzy Model

Urban rail transit has the advantages of large traffic capacity, high punctuality and zero congestion, and it plays an increasingly important role in modern urban life. Braking system is an important system of urban rail train, which directly affects the performance and safety of train operation and impacts passenger comfort. The braking performance of urban rail trains is directly related to the improvement of train speed and transportation capacity. Also, urban rail transit has the characteristics of high speed, short station distance, frequent starting, and frequent braking. This makes the braking control system constitute a time-varying, time-delaying and nonlinear control system, especially the braking force changes directly disturb the parking accuracy and comfort. To solve these issues, a predictive control algorithm based on T-S fuzzy model was proposed and applied to the train braking control system. Compared with the traditional PID control algorithm and self-adaptive fuzzy PID control algorithm, the braking capacity of urban rail train was improved by 8%. The algorithm can achieve fast and accurate synchronous braking, thereby overcoming the dynamic influence of the uncertainty, hysteresis and time-varying factors of the controlled object. Finally, the desired control objectives can be achieved, the system will have superior robustness, stability and comfort.     

Enhancing resilience assessment and bus bridging service design for large-scale rail transit systems under disruptions

This paper proposes a more computationally efficient approach for resilience assessment of rail transit system under disruptions. An improved linear programming model is developed to depict commuter flows and estimate system statuses. To address the computational challenge caused by the complexity of system, a four-step approach is proposed based on the proposed commuter flow model. In the first step, Origin-Destination (OD) pairs are divided into smaller groups and their flows under normal conditions are estimated by the proposed model separately, with the assumption that the railway capacity is sufficient relative to demand. Next, overall system statuses under normal conditions, including commuters on each train and spare capacities of each train are calculated by integrating results obtained in the first step. In the third step, system statuses under disruptions are estimated. In this step, we assume that unaffected commuters will not change their routes and flows of all affected commuters are estimated by a modified commuter model with given spare space of trains. Based on these outputs, several critical measures are introduced and calculated to quantify the resilience, resistance, and recovery ability of rail network systematically. We also demonstrate how our approach could be used to facilitate design and evaluation of bus bridging service. The proposed approach is demonstrated on the core part of Hangzhou rail transit network.     

基于乘客行为轨迹图的地铁站服务设计物理触点研究

目的根据调研发现并总结现有地铁站服务设计上存在的不足,提出相对科学合理的解决办法,来完善地铁站服务设计,提升现代都市乘客的乘车体验和城市轨道交通整体形象。方法以对乘客行为轨迹图的研究为切入点,在乘客进出站乘车行为轨迹的全视角下,从时间和空间两个维度,对乘客行为轨迹展开科学调研,深入挖掘地铁乘车过程中的服务缺口。结论据调研数据分析乘客乘坐地铁流程中亟待优化的物理触点,对现有安检机进行创新设计,提出一种免拉提安检机设计方案,对检票机、升降设备及其他数字与人工触点,提出优化建议。为优化地铁服务设计、提升轨道交通运输效率和乘客乘车体验,提供理论依据与实践参考。     

First-train timing synchronisation using multi-objective optimisation in urban transit networks

Missed transfers affect urban transportation by increasing the travel times and decreasing the travel possibility, especially in the case of longer headways. A synchronised timetable can improve the transport efficiency of urban mobility and become an important consideration in the operation of urban transit networks (UTN). A mixed integer programming model is proposed to generate an optimal train timetable and minimise the total connection time, which includes smooth synchronisations for rail first-trains and the seamless synchronisation from rail first-trains to the bus service. Meanwhile, to characterise the characteristics of first-trains, binary variables are used to denote key transfer directions. Subsequently, the Sub-network Connection Method in conjunction with Genetic Algorithm is designed to obtain near-optimal solutions in an efficient way. Finally, a real-world case study, 16 rail lines and 41 transfer stations, based on the Beijing metro network and travel demand is conducted to validate the proposed timetabling model. Preliminary numerical results show that our approach improves the synchronisation substantially compared with the currently operated timetable.     

地铁列车内室剩余空间的视觉化设计要素研究

目的 对列车内室剩余空间设计现状与乘客情感诉求进行研究,形成科学合理的剩余空间视觉化设计方法,指导视觉化设计实践,提升乘客的乘车体验.方法 以乘客行为需求的交互方式为切入点,提取剩余空间形式要素及乘客情感要素,利用虚拟现实技术,试图在视觉化设计原则的基础上,改变人机交互方式及信息传播途径,构建剩余空间视觉化交互情境,形成协调统一、智能化、人性化的列车内室剩余空间.结论 创新性定义了地铁列车内室剩余空间,推演得出了剩余空间视觉化设计与乘客情感诉求之间的制约关系,构建了地铁列车内室剩余空间视觉化设计方法论模型,并进行设计案例的实践验证,有效提升了乘客乘车体验,将为营造符合情感化需求的地铁内室环境提供新的思路与案例参考.     

Coasting point optimisation for mass rail transit lines using artificial neural networks and genetic algorithms

Energy consumption of a rail transit system depends on many parameters. One of the most effective methods of reducing energy consumption in a rail transit system is optimising the speed profile of the trains along the route. A new efficient method will be presented for the optimisation of the coasting points for trains in a global manner. The proposed approach includes realistic system modelling using multi-train, multi-line simulation software and application of artificial neural networks (ANN) and genetic algorithms (GA). The simulation software used can model regenerative braking and train performance at low voltages. Using ANN and GA together, optimal coasting points for long line sections covering five stations and two lines are achieved. Simulation software is used for creating training and test data for the ANN. These data are used for training of the ANN. Trained ANNs are then used for estimating energy consumption and travel time for new sets of coasting points. Finally, the outputs of the ANN are optimised to find optimal train coasting points. For this purpose, a fitness function with target travel time, energy consumption and weighting factors is proposed. An interesting observation is that the use of ANN increases the speed of optimisation. The proposed method is used for optimising coasting points for minimum energy consumption for a given travel time on the first 5 km section of Istanbul Aksaray-Airport metro line, where trains operate every 150 s. The section covers five passenger stations, which means four coasting points for each line. It has been demonstrated that an eight input ANNs can be trained with acceptable error margins for such a system.     

Reliability guarantee framework for the Sichuan–Tibet Railway

The Sichuan–Tibet Railway is facing extraordinary challenges in terms of construction, operation, and maintenance because of its extremely complicated natural environment and geological conditions. Consequently, countermeasures are necessary and urgent to ensure its safety and reliability in the whole life cycle. This study proposes a novel reliability framework to guarantee the ideal operation state of the Sichuan–Tibet Railway. Reliability application in many fields are summarized, including military equipment, rail locomotive, and railway engineering. Given the fact that the Sichuan–Tibet Railway is a complex giant system, Nine-Connotation was summarized (i.e., safety, inherent reliability, testability, maintainability, supportability, environmental adaptability, predictability, resilience, and durability) under the goal of optimizing the operational efficiency. On the basis of the concept of the Nine-Connotation and the understanding of reliability transmission mechanism, the framework of reliability for the Sichuan–Tibet Railway was established, which can facilitate a comprehensive and real-time evaluation of all situations with a clear hierarchy. The proposed framework is composed of a resilience management system, an integrated technology system, and a dynamic reliability assessment system. The pathway for its application on railway construction was developed in this study. The proposed framework can assist in well-informed decisions for the construction, as well as the operation of the Sichuan–Tibet Railway. On the basis of a top–down design concept for the first time, this study emphasizes the railway’s availability and validity to complete the assigned tasks as a whole, that is, operational efficiency. It also shows the reliability transmission and control mechanism of the railway’s giant complex system, innovating and establishing the management principle of great safety and great reliability over the life cycle.     

高铁车厢乘客设施的智能技术融合研究

目的 明确高铁乘客智能化功能需求,提出高效能的车厢乘客设施智能技术应用体系。方法 运用服务设计、行为分析、用户痛点研究、需求-满意度模型等进行智能化功能需求分析,通过专家访谈、文献梳理、总结归纳等方式进行类型研究。结果 在分析高铁乘客体验痛点的基础上,将其转化为具有优先级的智能化功能需求,进而明确车厢设施载体的智能化应用机会点,结合现有智能化技术分析,明确车厢7类区域设施与智能技术结合的原则及技术要素,最终提出高铁车厢乘客设施的智能技术应用体系。结论 在智慧高铁时代下,明确乘客设施智能化技术应用的要素及原则尤为必要,可以为未来的列车设计人员提供有关如何运用智能设施及其技术提升乘客体验的理论知识和实践参考。     

融合特征语义和模糊层次分析的空铁外观设计研究

目的 探究轨道列车与城市文化的关系,提升空铁外观设计中的文化内涵和文化认同,为空铁外观设计与评估提供实践指导和理论支撑。方法 以一款A型空铁外观设计为例,提出了一种融合特征语义和模糊层次分析的列车外观设计方法;首先基于模糊层次分析从民族性、地域性和时代性三个准则层出发分析特征语义指标权重,构建多层次评价模型;其次邀请专业设计人员对评价指标、评价层次进行评估,获得准则层与子准则层间的权重矩阵;最后运用模糊综合评价法来评估空铁外观设计方案。结果 基于特征语义指标权重分析结果,该方法将特征文化元素——蓝喉太阳鸟,有效地融入空铁外观设计,并经用户评估验证了方法的可行性。结论 该方法有助于辨识城市文化特征在空铁外观设计中的重要性,同时,探讨了方案存在的局限性,并提供了进一步优化设计意见,为提升空铁外观设计文化内涵提供参考。     

城轨车辆车体多重动力吸振器减振方法研究

为了让动力吸振器在降低轨道车辆车体振动的同时能够更好的适应车下剩余空间,根据多重动力吸振器原理,针对城轨车辆运行的特点,建立了包含多重动力吸振器的轨道车辆垂向振动模型,提出了适用于城市轨道车辆车体多重动力吸振器的设计方法。①讨论了载客量和速度变化对多重动力吸振器的减振性能的影响,指出了传统多重动力吸振器的局限性;②针对轨道车辆振动频率变化频繁的特点,提出了多重动力吸振器的目标频率的优化方法,从而避免了增振的情况出现;③以四条典型城市轨道线路为算例,利用DVA减振指标进行评价,分别获得了不同线路的车体多重动力吸振器的最优目标频率,并验证了该优化方法的有效性。研究结果表明:相同附加质量下,多重动力吸振器对车体的吸振能力要优于单个动力吸振器,考虑到实际的应用,在车体安装四重动力吸振器是较为适宜的选择;经过优化的多重动力吸振器在整个速度区间都能起到很好的减振效果,能够有效避免增振现象的发生;多重动力吸振器的目标频率的设计要针对不同的线路进行调整,特定线路需要特定设计才能发挥出最佳减振能力。该研究的工作为车体多重动力吸振器的研究和应用提供了参考依据。     

面向成都皮影文化的城轨列车通感转译设计

目的 提升城市轨道列车外观设计的文化内涵,丰富城市轨道列车工业设计的文化表征方法。方法 以成都皮影文化为例,基于通感转译理论,通过构建“通感桥”的关联属性实现对用户多感官意象活动中接收信息的转化和翻译,并结合层次分析法(AHP)将转译的造型语言进行聚类分析,最后从用户解码路径出发,逆向验证列车造型语言的科学性。结果 得到皮影人物局部特征、皮影人物形象、皮影人物颜色、皮影光影渐变、皮影雕刻纹理、皮影肌理和皮影人物轮廓线条7个本觉意象指标并计算了其各自权重。结论 将以上方法应用于城市轨道列车的外观设计实践中,形成了表达成都皮影文化意象的城市轨道列车外观方案,为地域文化融合的城市轨道列车提供了新思路,具有一定的参考价值。     

Effects of an adult passenger on young adult drivers’ driving speed: Roles of an adult passenger's presence and driving tips from the passenger

An adult passenger has been known to facilitate young drivers’ safe driving. This study examined whether the adult passenger's effect is produced by the simple presence of an adult passenger or by the driving tips offered by the passenger. Further, we examined whether the effect would be transferred to when a young driver drives alone without the adult passenger in the following session. Three groups of participants drove on expressway in a driving simulator, either alone, with a silent adult passenger, or with an adult passenger who gave advice on driving safety. After a break, participants in all three conditions drove on the same expressway alone. Results showed that participants who drove with an adult passenger providing driving tips drove more safely than the other groups, and the effect was transferred to even when they drove alone afterwards.     

大跨度公轨两用悬索桥风-车-桥耦合振动及抗风行车准则研究

将风、车、桥三者作为一个交互作用、协调工作的耦合动力系统,基于风-车-桥系统空间耦合分析模型,以一大跨度公轨两用悬索桥为例,采用自主研发的桥梁结构分析软件BANSYS(Bridge Analysis System)分析了风荷载作用下桥梁和车辆的动力响应,讨论了风速、车速及轨道交通布置方式等因素的影响;同时,基于合理的列车运行安全性和舒适性评价指标,对列车通过该桥时的走行安全性与舒适性进行了分析,得出了该悬索桥的抗风行车准则:当风速小于20m/s时,车速可达设计车速80km/h;当风速介于20m/s和25m/s之间时,车速不能大于60km/h;当风速大于25m/s时,应封闭轨道交通。     

Strategic analysis of China’s geothermal energy industry

China is an early user of geothermal energy, and its direct use ranks first in the world. Recent national strategies and policies have enabled China’s geothermal energy industry to enter a new era with important development opportunities. This paper investigates the strengths, weaknesses, opportunities, and threats (SWOT) to China’s geothermal energy industry from political, economic, social, and technological (PEST) perspectives. SWOT–PEST analysis indicates that the resources, market, and technological foundation exist for the large-scale development of China’s geothermal energy industry. However, it experiences constraints, such as unclear resource distributions, incomplete development of government regulations, incomplete implementation of national policies, unclear authority between governmental administrative systems, and lack of uniform technical standards and codes. Therefore, future development strategies have been proposed to provide technical support and policy tools for geothermal energy development. The recommendations to ensure its healthy and sustainable development include improving resource exploration, rationalizing administration systems, enhancing policy guidance and financial support, and cultivating geothermal talent.     

Simulation metamodelling with neural networks: An experimental investigation

Artificial neural networks are often proposed as an alternative approach for formalizing various quantitative and qualitative aspects of complex systems. This paper examines the robustness of using neural networks as a simulation metamodel to estimate manufacturing system performances. Simulation models of a job shop system are developed for various configurations to train neural network metamodels. Extensive computational tests are carried out with the proposed models at various factor levels (study horizon, system load, initial system status, stochasticity, system size and error assessment methods) to see the metamodel accuracy. The results indicate that simulation metamodels with neural networks can be effectively used to estimate the system performances.     

城轨列车车辆空气传播噪声预测模型

为缩短城轨列车车辆这样大型复杂结构早期的声学结构设计周期,建立了城轨列车车辆室内噪声和车外噪声通用的理论计算模型;提出了室外声源声功率级转换到室内声源声功率级的等效计算方法;针对城轨列车车体常用的中空铝型材双层结构的隔声量进行了理论推导,并分析了表面粘附辅助材料后组合隔声结构的隔声量;根据计算模型对某城轨列车的噪声进行了预测,计算结果与测试结果虽存在一定的偏差,但仍在可接受范围之内。预测模型能为新车型研发和老车型的声学结构改进快速提供设计依据。     

地铁内部设施的情感化设计研究

目的提高乘客对于乘坐地体的体验,让乘客更加愉快地接受和乘坐地铁。方法基于情感化设计理论,从本能、行为和反思3个层面出发,结合乘客对地铁内装设计的情感认知来分析对乘客的影响。结论将情感化设计理论融入地铁内饰设计中,并结合乘客生理需求和心理需求不仅可以获得良好的功能体验、视觉体验,而且能获得良好的情感体验。     

Simulation of wheel–rail contact forces

This paper summarizes the forces that develop in the contact patch between the wheel and rail in a railway vehicle. The ways that these forces govern the behaviour of a vehicle running on straight and curved track are explained and the methods commonly used to calculate and utilize the forces summarized. As an illustration, the results from a computer simulation of a typical UK passenger train are presented and certain aspects examined.