The ring-rolling process was first developed in the UK in the mid nineteenth century and is still widely used as the preferred method of forming seamless rings for many aerospace and automotive applications, as well as for producing railway wheels and tyres. This thesis describes the development of a finite element based mathematical model that can be used to simulate the process. The model has been developed with the intention of practical application within railway wheel manufacturer Adtranz New Wheel Products Division. A detailed review of previous research on the process is presented. The key observation from that review is that all attempts at modelling ring rolling have suffered from severe run time difficulties which are predominantly due to lack of constraint and the large number of increments required to complete a simulation. Based on this fact the focus of development activities has been on identifying ways in which the simulation can be run in realistic time frames. The usefulness of a simplified 2D method is assessed, with the conclusion that while some beneficial information might be gained by such an approach, 3D simulation is the only way of fully representing material deformation during the process. Attempts at improving run time of 3D modelling have focused on two main areas. Firstly an efficient arbitrary Lagrangian Eulerian finite element flow formulation has been adopted. This gives the advantages of allowing mesh density to be concentrated on roll gap regions, and removing some of the convergence problems associated with frequent contact changes. Secondly the issue of solution of the discretised flow formulation equations is examined in some detail. A range of well known solution methods are considered as potential ways of improving on direct methods, with limited success. Significant potential benefits are found to result however from a new approach, the successive preconditioned conjugate gradient method. This method, together with tests of its effectiveness, is described in some detail. The resulting model is tested against experimental work performed by previous authors. Attempts to integrate the work into Adtranz are also described. These have included consideration of usability and management issues, and illustrative case studies.

This thesis presents the fault diagnosis of an electric train door system. To operate an efficient rail system it imperative that equipment such as train doors are maintained thoroughly, preferably using a predictive maintenance scheme. Initially, a life size testrig was constructed and information regarding frequent door faults collected from both the maintainers and manufacturers. Thirteen faults were induced on the test-rig and a comprehensive dataset collected. It was found that the main incipient faults are related to changes in the friction. By examining the steady state operating conditions it was found that the friction could be adequately described by first order characteristics. The dynamics of the electro-mechanical system can be described by a basic second order differential equation. The most logical approach to diagnose physical faults is to estimate the physical parameters of the system. For this purpose, various continuous-time model identification techniques are discussed. State variable-pre-filtering and linear integral pre-filtering can be used to solve the problem of noise-accentuated derivatives; these filters are also convenient for on-line implementation. However, linear integral filtering is much more straightforward in design and computationally faster for lower order systems. The prefilters are carefully designed to accommodate fast system responses under fault conditions; however, adaptive type pre-filtering provides an alternative solution. A neuro-fuzzy svstem that processes the parameter estimates is proposed to isolate faults', such a system combines the strengths of neural networks and fuzzy inference systems. Initially, a clustering algorithm is used to identify a fuzzy model, which is implemented in a neural architecture for training. Prior to training, redundant membership functions are removed, increasing the readability of the inference system. The neuro-fuzzy system has high classification success and a transparent rule-base that can be used by maintainers. Fault identification is achieved through direct implication of the parameter estimates. To make practical implementation feasible, it is proposed that a three-layer distributed hierarchical architecture be used. This incorporates the manufacturer's control alarms, dedicated fault diagnosis algorithms and the train management system for data communication; an interface to the maintenance system is also available. The architecture is generic and could be used for fault diagnosis of multiple low-cost assets.

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The thesis describes a study of automatic driving in a guided transport system. Full scale practical experiments have been carried out with the co-operation of British Railways Research & Development Division. Considerable attention is paid to the problem of line capacity with a rigorous safety constraint and operational and engineering limitations. An understanding of vehicle interactions under discontinuous and continuous signalling systems is demonstrated, leading to an explanation of why the theoretical steady state plain line capacities are not realisable. This is extended to show the importance of the vehicle trajectory and how shaping the trajectory can minimise journey time, headway, energy consumption and other performance criteria, bearing in mind the inconsistency of these aims and demonstrating the trade-offs. Some theoretical work on generalised control syst'ems is described and this demonstrates the need for a greater understanding of practical engineering constraints. Consequently, available literature on train performance has been studied and experiments carried out with an instrumented train. The results indicate an inadequate understanding of train behaviour in much that has previously been pUblished. A mathematical model of the test train has been formulated and with the help of the Mathematics Applications Section of British Rail, this has been simulated on the computer. It is evident that railway braking systems partictilarly those employing cast iron friction blocks,introduce significant control problems. The control system of the train is demonstrated to be non-linear and subject to severe stochastic disturbances of both environmental and system parameters. Instrumentation of the system is difficult and the report goes to some length to identify the fundamental limitations of measurement of the principal state variables. A complete single vehicle control system has been realised on the British Rail Test Line at Mickleover. It is anticipated that an engineered system would be microprocessor based and experience has been gained with Intel devices in the communications system, whilst a mini-computer system was considered more appropriate as a test bed for control principle development. The results of the performance evaluation and control tests at Mickleover give significant insight into the likelihood of realisation of some of the theoretical ideals developed in the earlier study. The report includes details of some of the authors more recent work with Br;tish Rail on a project to implement pilot scheme automatic train operation. The experimental work for this project has included the implementation of a simple automatic driver on a Motorola Microprocessor.

Following successful implementation of inerters for passive mechanical control in racing cars, this research studies potential innovative solutions for railway vehicle suspensions by bringing the inerter concept to the design of mechatronic systems. The inerter is a kinetic energy storage device which reacts to relative accelerations; together with springs and dampers, it can implement a range of mechanical networks distinguished by their frequency characteristics. This thesis investigates advantages of inerter-based novel devices to simplify the design of active solutions. Most of the research work is devoted to the enhancement of vertical ride quality; integrated active-plus-novel-passive solutions are proposed for the secondary suspensions. These are defined by different active control strategies and passive configurations including inerters. By optimisation of the suspension parameters, a synergy between passive and active configurations is demonstrated for a range of ride quality conditions. The evidence of cooperative work is found in the reduction of the required active forces and suspension travelling. This reveals a potential for reducing the actuator size. Benefits on power requirements and actuator dynamic compensation were also identified. One of the strategies features a nonlinear control law proposed here to compensate for 'sky-hook' damping effects on suspension deflection; this, together with inerter-based devices attains up to 50% in active force reduction for a setting providing 30% of ride quality enhancement. The study is developed from both, an analytical and an engineering perspective. Validation of the results with a more sophisticated model is performed. The lateral stability problem was briefly considered towards the end of the investigation. A potential use of inerter-based devices to replace the static yaw stiffness by dynamic characteristics was identified. This leads to a synergy with 'absolute stiffness', an active stability solution for controlling the wheelset 'hunting' problem, for reducing the creep forces developed during curve negotiation.

Cette thèse est consacrée à la planification robuste du matériel roulant ferroviaire dans un contexte de transport de voyageurs régional. Il s'agit de déterminer pour chaque engin une suite de trajets à réaliser sur une période donnée de façon à résister au mieux aux aléas pouvant apparaître en opérationnel. Dans ce but, nous proposons une définition et une caractérisation de la robustesse par des indicateurs propres au contexte d'étude. Nous abordons le problème par une approche structurelle différente des approches robustes classiques qui permet d'agir sur la structure d'une solution en fonction des indicateurs définis. Trois méthodes sont alors mises en œuvre dans le cadre de ce travail. Une résolution approchée par une heuristique gloutonne et une recherche locale permet d'obtenir des solutions rapidement. Une méthode de résolution approchée par génération de colonnes a été développée afin de prendre en compte plus de contraintes de façon intégrée. Une méthode basée sur un programme linéaire en nombres entiers résolu exactement traite un problème plus général. Afin de limiter le coût de la robustesse, ces méthodes sont basées sur un existant à SNCF répondant au problème de planification des ressources matérielles à coûts de production minimaux. Un outil de simulation du comportement des solutions en situation perturbée permet de comparer les solutions entre elles par évaluation des indicateurs de robustesse. Des expérimentations sur des instances réelles ont prouvé la pertinence des approches et ont mené à l'industrialisation d'un prototype. / This thesis deals with robust rolling-stock planning problems for passenger regional trains. It consists in building robust rolling-stock schedules to operate trains under technical constraints while anticipating operational disturbances that can occur. First of all, we define indicators to characterize robustness in context. We use these indicators to have an effect on solutions that we build. This structural approach is unusual compared to classical robust optimization approaches. We have implemented three methods to solve the problem. A sequential heuristic method enhanced by a local search gives solutions quickly. A column-generation method calculates approximate solutions.An integer linear program is solved exactly to obtain solutions to a global problem. These methods are based on an existing tool at SNCF that optimizes the rolling-stock planning problem to assure optimal production costs. A simulation tool evaluates robustness indicators to compare solutions. Tests on real instances have proved the relevance of the approaches and have lead to the use of a prototype in production