A generalised approach to machine control

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.