In this study a closed-loop cruise controller to minimise the running costs of the heavy-haul train is proposed. The running costs of a heavy-haul train are dependent on its travelling time, maintenance costs and energy consumption during the trip. The Coallink train with the new train technologies, Distributed Power (DP) traction and Electronically Controlled Pneumatic (ECP) brake system, is the centre of the study. A literature study on existing train control, both passenger and heavy-haul trains, is carried out to build up a knowledge base. Many different techniques for train handling were observed, their features in relation to heavy-haul ECP trains are discussed. From these backgrounds, a comprehensive longitudinal train model is proposed and successfully validated with real-life data from Spoornet. In the model, both static and dynamic in-train forces are studied, as well as energy consumption. This is possible by modelling each locomotive and wagon as an individual unit. The equations of motion for the train with coupled units and additional non-linearities, such as traction power limits, are considered. An open-loop controller for maintaining equilibrium velocity is designed. During transient velocity changes, a transient controller for calculating the required additional acceleration and deceleration is designed and validated. Because locomotive traction settings are only available in discrete notches, quantisation conversion from force into notches results in input chattering. In addition, during brake to traction transitions, the locomotives receive a sudden traction demand which results in spikes in in-train forces. To avoid these problems, input filtering is performed for these inputs. Closed-loop controllers based on LQR method, optimised for in-train forces, energy consumption and velocity regulation respectively, are designed and compared. To overcome the communication constraints, a fencing concept is introduced whereby the controller is reconfigured adaptively to the current track topology. Different train configurations in terms of availability of additional control channels for both traction and braking are compared, as well as their effects on dynamic and static in-train force. These configurations are unified, distributed and individual traction and brake controls. The results from these different configurations are compared to recorded train data and given in this study. From the results, it is found that the closed-loop controller optimised for in-train force is able to provide the best overall improvement out of the three controllers. / Dissertation (MEng)--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / Unrestricted

The railway industry in Ethiopia has been an important way of communication and transportation for a long time. It is a developing sector with many national plans for future investments. However, the current major corridors of Ethio­-Djibouti and Awash­-Weldiya have interoperability issues due to two different signalling systems being used. Thus, this study was undertaken with the objectives of assessing technical interoperability of the Chinese signalling system (CTCS) and the European signalling system (ETCS), identifying a possible technical solution regarding the interoperability issues, and assessing the economic benefits of a harmonized system. Compatibility of the two signalling systems was analyzed particularly with respect tothe technical configurations by thoroughly investigating each system’s features and making interviews and having discussions with professionals who worked with the two systems. In addition, a life cycle cost analysis of the Ethio­Djibouti signalling system was done with data obtained from Ethiopian Railway Corporation and compared with average life cycle costs of ETCS level 1. After analyzing each system, two possible technical solutions were found to achieve interoperability between the two systems used in Ethiopia currently. The first technical solution is upgrading Ethio­Djiboutirailway line from the current CTCS level 0 to CTCS level 2 to be compatible with the new Awash­Weldiya line which will use ETCS level 1. The second technical solution to make the two systems interoperable is to install ERTMS as an overlay on the existing CTCS level 0 as ERTMS is designed as an overlay system that could be installed on top of an existing national infrastructure and vehicles. However, these technical solutions have to be tested in laboratory and onsite with respect to their practical and economical feasibility. / Järnvägsindustrin i Etiopien har länge varit viktig för kommunikation och transport. Det är en sektor under utveckling med många nationella planer för framtida investeringar. De nuvarande korridorerna i Ethio­Djibouti och Awash­Weldiya har emellertid interoperabilitetsproblem på grund av två olika signalsystem. Detta examensarbete har analyserat kompatibiliteten för de två signalsystemen särskilt med avseende på de tekniska konfigurationerna genom att noggrant undersöka varje systems funktioner och genom intervjuer och diskussioner med yrkesverksamma somhar arbetat med de två systemen. Dessutom genomfördes en livscykelkostnadsanalys av Ethio­Djibouti signalssystemet med den data som erhölls från Ethiopian Railway Corporation. Efter analys av varje system hittades två möjliga tekniska lösningar för att uppnå interoperabilitet mellan de två systemen som används i Etiopien för närvarande. Den första tekniska lösningen är att uppgradera Ethio­Djiboutis järnvägslinje från nuvarande CTCS nivå 0 till CTCS nivå 2 för att vara kompatibel med den nya Awash­Weldiya­linjen som kommer att använda ETCS nivå 1. Den andra tekniska lösningen för att göra de två systemen interoperabla är att installera ERTMS som ett överlägg på det befintliga CTCS­0 signalsystemet, eftersom ERTMS är utformat som ett överläggssystem som kan installeras ovanpå en befintlig nationell infrastruktur. Dessa tekniska lösningar måste dock testas i laboratorium och i fält med avseende på deras praktiska och ekonomiska genomförbarhet.

Esta dissertação apresenta um estudo da viabilidade de aplicação de ferramentas de Inteligência Artificial, em especial da aplicação da lógica nebulosa preditiva (lógica fuzzy), em sistemas de controle automático de trens. Para isto, um panorama do contexto de aplicação do estudo é apresentado, incluindo a problemática dos transportes nas grandes cidades e a utilização de técnicas de computação em sistemas metroferroviários. Também são apresentados os princípios básicos de controle automático de trens, de lógica nebulosa preditiva e de sistemas de controle, particularmente os sistemas especialistas e as aplicações críticas de controle. Um modelo de um sistema de controle utilizando lógica nebulosa preditiva é então proposto e detalhado. Em seguida, estudos de caso para os trens do metropolitano de Sendai (Japão) e de São Paulo são efetuados. Simulações, testes comparativos e a análise dos resultados são realizados, levando às considerações finais sobre a viabilidade da aplicação. A conclusão é que, mesmo se tratando de uma aplicação crítica de controle, envolvendo a segurança dos passageiros, a utilização de ferramentas de Inteligência Artificial, especialmente a lógica nebulosa preditiva, é perfeitamente viável, desde que uma atenção especial com a segurança do sistema seja tomado. Neste caso, esta atenção é tomada por meio da implantação de um módulo supervisor (módulo ATP) que realiza uma monitoração constante das entradas e saídas do sistema de controle. O ATP atua, preferencialmente, ao sistema de controle para garantir a sua segurança. Embora as normas européias (IEE e CENELEC) não recomendem a utilização de ferramentas de Inteligência Artificial em aplicações críticas de controle, este estudo demonstra que é possível efetuar a aplicação destas ferramentas, aproveitando os benefícios por elas proporcionados, sem comprometer a segurança do sistema. / This dissertation presents a study on the viability of applying Artificial Intelligence tools, especially predictive fuzzy logic application, in automatic train control systems. For this purpose, an overview of the study application context is presented, including transportation troubling in big cities and computational techniques used in subway and railway systems. The basic principles of automatic train control, predictive fuzzy logic and control systems, particularly specialist and control critical systems applications are also presented. A model for a control system using predictive fuzzy logic is then proposed and detailed. Next, study cases for Sendai (Japan) and São Paulo subway trains are conducted. Simulations, comparative tests and results analysis are carried out, leading to the final considerations about the application viability. The conclusion is that, even being a critical control application, involving passenger safety, the use of Artificial Intelligence tools, especially predictive fuzzy logic, is perfectible viable, since special attention is given to the safety of the system. In this case, this attention is given by means of the implementation of a supervisory module (ATP module) that constantly monitors control system inputs and outputs. The ATP acts preferably on the control system in order to guarantee its safety. Although European standards (IEE and CENELEC) do not recommend the use of Artificial Intelligence tools in critical system applications, this study shows that it is possible to apply these tools, enjoying the benefits provided by them, without compromising the system safety.

Esta dissertação apresenta um estudo da viabilidade de aplicação de ferramentas de Inteligência Artificial, em especial da aplicação da lógica nebulosa preditiva (lógica fuzzy), em sistemas de controle automático de trens. Para isto, um panorama do contexto de aplicação do estudo é apresentado, incluindo a problemática dos transportes nas grandes cidades e a utilização de técnicas de computação em sistemas metroferroviários. Também são apresentados os princípios básicos de controle automático de trens, de lógica nebulosa preditiva e de sistemas de controle, particularmente os sistemas especialistas e as aplicações críticas de controle. Um modelo de um sistema de controle utilizando lógica nebulosa preditiva é então proposto e detalhado. Em seguida, estudos de caso para os trens do metropolitano de Sendai (Japão) e de São Paulo são efetuados. Simulações, testes comparativos e a análise dos resultados são realizados, levando às considerações finais sobre a viabilidade da aplicação. A conclusão é que, mesmo se tratando de uma aplicação crítica de controle, envolvendo a segurança dos passageiros, a utilização de ferramentas de Inteligência Artificial, especialmente a lógica nebulosa preditiva, é perfeitamente viável, desde que uma atenção especial com a segurança do sistema seja tomado. Neste caso, esta atenção é tomada por meio da implantação de um módulo supervisor (módulo ATP) que realiza uma monitoração constante das entradas e saídas do sistema de controle. O ATP atua, preferencialmente, ao sistema de controle para garantir a sua segurança. Embora as normas européias (IEE e CENELEC) não recomendem a utilização de ferramentas de Inteligência Artificial em aplicações críticas de controle, este estudo demonstra que é possível efetuar a aplicação destas ferramentas, aproveitando os benefícios por elas proporcionados, sem comprometer a segurança do sistema. / This dissertation presents a study on the viability of applying Artificial Intelligence tools, especially predictive fuzzy logic application, in automatic train control systems. For this purpose, an overview of the study application context is presented, including transportation troubling in big cities and computational techniques used in subway and railway systems. The basic principles of automatic train control, predictive fuzzy logic and control systems, particularly specialist and control critical systems applications are also presented. A model for a control system using predictive fuzzy logic is then proposed and detailed. Next, study cases for Sendai (Japan) and São Paulo subway trains are conducted. Simulations, comparative tests and results analysis are carried out, leading to the final considerations about the application viability. The conclusion is that, even being a critical control application, involving passenger safety, the use of Artificial Intelligence tools, especially predictive fuzzy logic, is perfectible viable, since special attention is given to the safety of the system. In this case, this attention is given by means of the implementation of a supervisory module (ATP module) that constantly monitors control system inputs and outputs. The ATP acts preferably on the control system in order to guarantee its safety. Although European standards (IEE and CENELEC) do not recommend the use of Artificial Intelligence tools in critical system applications, this study shows that it is possible to apply these tools, enjoying the benefits provided by them, without compromising the system safety.

by Alexander H. Levis and Michael Athans. / Bibliography: p. 27. / PB 177 669. / Prpared for the U.S. Dept. of Transportation under Contract C-85-65, DSR Project no. 76105.

This thesis describes research and development. work carried out by the author into the control of traction and braking systems on rail vehicles. After a review of recent developments, the problem of. driving a train under minimum-energy control subject·to timetable and operational constraints is discussed. This is partitioned into two sections. Firstly, target time and velocities for key pOints on the journey are computed; these are communicated to or stored on the train, together with route and vehicle data. Secondly, an on-board digital system drives the train to each target according to control algorithms which incorporate a predictorcorrector module, whose function is to determine which of two criteria of performance is to be used (minimum-energy when running early or on-time, minimum-time when running late). Most of the thesis is devoted to the analysis and design of the train-borne control system. The general form of the optimal control (of tractive or braking effort) is determined by the application of Pontryagin's Maximum Principle over each section of the journey. However, the moments of transition between the various modes of control are calculated by a method which involves a lookahead model in the predictor module, rather than by iterative solution of the state and co-state equations . An important aspect of the design is the dynamic response of the braking SUb-system, which may include a substantial pneumatic transport lag within the control loop. S-plane and z-plane design procedures for the required discrete control algorithms to.achieve a specified transient response are derived. The thesis concludes with a chapter on the instrumentation required for the train-borne control system.

Connected and Autonomous Vehicles (CAVs) benefit from both connectivity between vehicles and city infrastructures and automation of vehicles. In this respect, CAVs can improve safety and reduce traffic congestion and environmental impacts of daily commutes through making collaborative decisions. This dissertation studies how to reduce the energy consumption of vehicles and traffic congestion by making high-level routing decisions of CAVs. The first half of this dissertation considers the problem of eco-routing (finding the energy-optimal route) for Plug-In Hybrid Electric Vehicles (PHEVs) to minimize the overall energy consumption cost. Several algorithms are proposed that can simultaneously calculate an energy-optimal route (eco-route) for a PHEV and an optimal power-train control strategy over this route. The results show significant energy savings for PHEVs with a near real-time execution time for the algorithms. The second half of this dissertation tackles the problem of routing for fleets of CAVs in the presence of mixed traffic (coexistence of regular vehicles and CAVs). In this setting, all CAVs belong to the same fleet and can be routed using a centralized controller. The routing objective is to minimize a given overall fleet traveling cost (travel time or energy consumption). It is assumed that regular vehicles (non-CAVs) choose their routing decisions selfishly to minimize their traveling time. A framework is proposed that deals with the routing interaction between CAVs and regular uncontrolled vehicles under different penetration rates (fractions) of CAVs. The results suggest collaborative routing decisions of CAVs improve not only the cost of CAVs but also that of the non-CAVs. This framework is further extended to consider congestion-aware route-planning policies for Autonomous Mobility-on-Demand (AMoD) systems, whereby a fleet of autonomous vehicles provides on-demand mobility under mixed traffic conditions. A network flow model is devised to optimize the AMoD routing and rebalancing strategies in a congestion-aware fashion by accounting for the endogenous impact of AMoD flows on travel time. The results suggest that for high levels of demand, pure AMoD travel can be detrimental due to the additional traffic stemming from its rebalancing flows, while the combination of AMoD with walking or micromobility options can significantly improve the overall system performance.

The Diploma thesis deals with the problem of energy-efficient train control. It presents the basic survey of mathematical models used in the problem of energy-efficient train control, analysis of optimal driving regimes, determining optimal switching times between optimal driving regimes and timetabling of the train. The mathematical formulation of the problem is done using Newton's second law of motion and other known physical laws. To analyse optimal driving regimes and determine the switching times between optimal driving regimes, we apply tools of optimal control theory, particularly Pontryagin's Maximum Principle. The timetabling of the train is discussed from the numerical solution of the settled non-linear programming problem.

The diploma thesis is dealing with the area of controlling and safety technology for the railway transportation. The problems of the design and practical realization of an functional sample of switching unit supplying the ends of a track circuit are solved here. The switching unit enables the operation of the train control system. The outline of the design is formed by a power switch operated with a microprocessor. In addition, for the increase in safety the switching unit contains a control processor, which is controlling the right function of a work microprocessor and the failure-free state of a power switch.

The main objective in optimizing train control is to eliminate the waste associated with classical design where train separation is determined through the use of "worst case" assumptions to calculate Safe Braking Distances that are invariant to the system. In fact, the worst case approach has been in place since the beginning of train control systems. Worst case takes the most conservative approach to the determination of train stopping distance, which is the basis for design and capacity of all train control systems. This leads to stopping distances that could be far more than actually required under the circumstances at the time the train is attempting to brake. A new train control system is proposed that utilizes information about the train and the conditions ahead to optimize and minimize the Safe Braking Distance. Two methods are proposed to reduce safe braking distance while maintaining an appropriate level of safety for the system. The first introduces a statistical method that quantifies a braking distance with various hazards levels and picks a level that meets the safety criteria of the system. The second method uses train mounted sensors to determine the adhesion level of the wheel and rail to determine the appropriate braking rate for the train under known circumstances. Combining these methods provides significant decreases in Safe Braking Distances for trains. A new train control system is utilized to take advantage of these features to increase overall system capacity. / Electrical and Computer Engineering