The intrinsic complexity and variability of typical real time control problems
makes a generalised approach to producing control systems difficult to specify. Due
to a lack of standardisation, current machine controllers are usually extremely difficult
to configure, support and integrate together in a generalised manner. These problems
have severely hindered the development and subsequent application of advanced
factory automation. The exploitation of advanced computer technology, particularly
modern software methods can now enable a consistent machine control structure to be
maintained for diverse applications of widely differing complexity. This thesis
addresses the need for a major change in the design of machine control systems and
proposes the use of a reference architecture which offers a consistent approach to the
control of real time industrial operations.
A broad based look at existing control systems focuses on the functiona,lity
they currently offer in the control of various categories of industrial operations. A
study of current manufacturing automation highlights the functional similarities between
the control requirements of different industrial processes both in terms of their
control structure and hierarchical communication requirements for factory integration.
Given this commonality it is proposed that all industrial controllers should logically be
based upon a common hardware independent architecture. A design methodology has
been devised, termed Universal Machine Control (UMC) which enables individual
machine controllers to be created (with functionality closely matched to their specific
applications) whilst still maintaining common structural and communications features.
This methodology aims to simplify the process of defining, programming and
controlling systems built up from user defined mechanical hardware. A modular
design framework or reference architecture for machine control has been derived
which allows control systems to be modelled in a generalised manner.
A particular implementation of the control architecture conforming to this
reference model and an associated definition environment have been created. The
implementation is based on the selective use of modern computer methods and
emerging standards for real-time control. A demonstration system has been produced
targeted at the flexible assembly of printed circuit boards. The possible application
areas for this control philosophy are however extremely diverse and it could have a
significant impact on automation methods.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.