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.
A Doctoral Thesis. Submitted in partial fulfillment of the requirements for the award of Doctor of Philosophy of Loughborough University.