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This work addresses the problem of difficulties in the implementation of Computer Aided Production Management systems, and presents a methodology for their implementation which significantly improves on current practice. The methodology provides a structured approach which leads the company through a series of strategic business decisions which establish the context within which the solution must operate. The work focusses attention upon the design of the whole system with respect to the relationship between computerised functions and the infrastructure of human elements which facilitate and govern the system's operation. A model of the tasks involved in production management is presented. The model is used to structure decisions relating to the design of the infrastructure. The research work described proceeded in two distinct stages. In the first stage the author participated with-other-researdhers Who jointly developed the framework of the process methodology for CAPM implementation. This stage provides the context for the development of the task model approach to the design of the system, which represents the author's individual contribution - (see section 1.8). The task model can be used as a-tool-to identify the options available for the way each task within production management may .be executed, giving the user a basis for the design,of.a.particular system while not advocating any particular solution. By the use of this approach the user is encouraged to consider the,options, pailatag, and to adopt an integrated approach which looks at all arPas of production management, not only those for which there is a pressing problem or a tempting solution. This work results in a contribution to the development of the process methodology, the development of a tool in the CAPM task model and a review of the factors involved in the design of a system including both human and computerised elements.

In modern manufacturing technology with increasing automation of manufacturing processes and operations, the need for automated measurement has become much more apparent. Computer measuring machines are one of the essential instruments for quality control and measurement of complex products, performing measurements that were previously laborious and time consuming. Inspection of sculptured surfaces can be time consuming since, for exact specification, an almost infinite number of points would be required. Automated measurement with a significant reduction of inspected points can be attempted if prior knowledge of the part shape is available. The use of a vision system can help to identify product shape and features but, unfortunately, the accuracy required is often insufficient. In this work a vision system used with a Coordinate Measuring Machine (CMM), incorporating probing, has enabled fast and accurate measurements to be obtained. The part features have been enhanced by surface marking and a simple 2-D vision system has been utilised to identify part features. In order to accurately identify all parts of the product using the 2-D vision system, a multiple image superposition method has been developed which enables 100 per cent identification of surface features. A method has been developed to generate approximate 3-D surface position from prior knowledge of the product shape. A probing strategy has been developed which selects correct probe angle for optimum accuracy and access, together with methods and software for automated CMM code generation. This has enabled accurate measurement of product features with considerable reductions in inspection time. Several strategies for the determination and assessment of feature position errors have been investigated and a method using a 3-D least squares assessment has been found to be satisfactory. A graphical representation of the product model and errors has been developed using a 3-D solid modelling CAD system. The work has used golf balls and tooling as the product example.

In an environment of world competition in manufacturing, the application of information technology (IT) is seen an important component in the achievement of performance improvement. Computer Integrated Manufacturing (CIM) is interpreted as the realisation of an IT strategy for manufacturing to achieve competitive advantage. The thesis identifies the growing problems of change and uncertainty in manufacturing which make effective, centralised, monolithic control ever more difficult to achieve by automation. An alternative, more manageable approach is deonstrated in which artificial intelligence (AI) is distributed across an enterprise in order to carry out decision making at the locations where it would naturally take place. The concept of an intelligent nodal architecture has been defined, differentiating between the functions of decision making, recording business transactions and enabling communication. A detailed case study was undertaken of a manufacturer of printed circuit boards to investigate the criteria for effective application of the intelligent architecture to decision making procedures. In the process, the IDEF-O analytical methodology was critically appraised, and the conclusion reached that design based on top-down analysis is inferior to evolutionary design of manufacturing systems. A simulator to support the proposed intelligent architecture was developed using object-oriented, hypermedia software, and tested with a small scale factory model. The simulator, then applied to the case study, demonstrated the potential for improving performance using Kanban techniques implemented by means of distributed intelligent nodes. It was also observed that AI based simulation could provide better planning tools than centralised systems such as MRP (Manufacturing Resource Planning). In conclusion, evidence was provided to support the use of distributed intelligence in manufacturing automation and an intelligent architecture proposed and tested using simulation. The research shows potential for commercial development.

Thorough investigation and planning are essential steps in the deployment of Flexible Manufacturing Systems. At the present time, the most popular method of planning and analysis of these systems is computer-based modelling and simulation of which many varieties are commercially available. Ideally, during the modelling phase, the modeller should pay particular attention to such important details as reliability, damage propagation patterns, condition monitoring scenarios and the supervision aspects of these system as these factors are critical to the operation and performance of any envisaged configuration of FMS or its subsystems. In practice however, these are among the most neglected aspects of the models being constructed at the present time. This is in part because the present generation of commercially available simulation languages and environments are in many respects ill-equipped to deal with the challenges posed by the modelling of FMS. This thesis investigates the potential suitability of contemporary reliability and fault-mode description and analysis tools for inclusion within simulation models. Contemporary research work in analytical arid simulation-based reliability and fault-mode modelling and analysis of computer-integrated and flexible manufacturing systems have been investigated. A number of guidelines for the development of CIM and FMS simulation models have been developed. Four standard FMS models are developed and utilized as application examples in thesis. Analytical reliability techniques have been re-examined with special reference to the modelling of computer-integrated and flexible manufacturing systems. The potential sources of error and pitfalls of discrete-event simulation modelling have been outlined. The effect of the host languages, the different simulation time advancement modes, and the traditionally prescribed break-down modelling techniques have been investigated. Contemporary technology, programming and modelling concepts have been illustrated using PCModel and PROLOG. Fundamentals of "accurate" knowledge-based simulation modelling have been described and an alternative object-like structural implementation in a declarative environment has been proposed for the simulation models and tools. A detailed examination of the pre-requisites for the accurate simulation of reliability, fault-mode, and condition monitoring aspects of FMS has been performed. Some of the reliability and fault-mode modelling and analysis tools have been considered for their potential suitability as discrete-event simulation tools. Various possible resource-aging modes, health monitoring modules, and repairability /maintenance models have been developed. Micro-failure modelling and analysis has been proposed as an alternative to the traditional macro-failure modelling and analysis. Techniques for modelling of systems incorporating combinations of new and used equipment have been developed. A multi-phase development and demonstration of simulation models incorporating the tools and concepts proposed and cultivated during the course of the research has been undertaken. In each case, the model's evolution and the subsequent variations in its behaviour have been followed and examined from its bare-bone prototype to its fully developed stage. The research results in better understanding of reliability, condition monitoring and knowledge representation issues in simulation.

The application of Flexible Manufacturing Systems (FMSs) has an effect in competitiveness, not only of individual companies but of those countries whose manufactured exports play a significant part in their economy (Hartley, 1984). However, the increasing use of FM Ss to effectively provide customers with diversified products has created a significant set of operational challenges for managers (Mahmoodi et al., 1999). In more recent years therefore, there has been a concentration of effort on FMS scheduling without which the benefits of an FMS cannot be realized. The objective of the reported research is to investigate and extend the contribution which can be made to the FMS scheduling problem through the implementation of computer-based experiments that consider real-time situations.

An expert system approach to fault diagnosis of fluid power circuits is considered with emphasis on leakage flow detection, and for valvecontrolled cylinders. Two test rigs were used, one being a solenoid-valve controlled cylinder operated directly and in an open-loop mode, the other being a servo-valve controlled actuator operated by microcomputer and in a closed-loop mode. Both systems incorporated the use of on-line dynamic data, and for the closed-loop case operation and fault diagnosis was integrated into an automated procedure. Flow leakage detection was considered a priority, and an alternative approach using displaced volumes was successfully implemented. The research work concentrated initially on the use of an expert system and the establishment of an appropriate knowledge base using a hybrid reasoning approach. This approach was found to be excellent for single-fault conditions but could not differentiate components of multiple-fault conditions, other than that they existed, due to the use of a minimum number of flow sensors. Additional techniques were then considered for the closed-loop control system utilising steady-state position error, time series analysis, and Artificial Neural Networks. It was found that the consideration of steady-state error gave information complementary to the existing knowledge base but could not give any additional information. The use of an artificial neural network was found to give more information with regards to multiple-fault conditions, resulting in a percentage probability for each fault combination.

Within manufacturing, increasing interest in being placed in the possibilities of integrated process planning and scheduling. Separating these two related tasks can impose constraints, on the final schedule, which are both undesirable and unnecessary. These constraints arise from premature decisions regarding the allocation of manufacturing resources. By making use of flexible process plans, these decisions can be delayed until the most appropriate time: during scheduling. The decisions can then be made on the basis of objectives common to both tasks (such as the minimisation of manufacturing cost). This thesis outlines an approach to manufacturing planning which is based on a highly general formulation of the problem. This integrated process planning/scheduling problem can be viewed as a generalisation of process plan optimisation, a task which is also considered in detail. A novel approach to plan optimisation is proposed, which in turn forms the basis for integrated planning and scheduling. Some research into integrated planning/scheduling has been reported in the literature. However, researchers differ in the way they formulate the integrated task. This thesis therefore attempts to outline a general framework for the characterisation of integrated process planning and scheduling problems. This considers both the degree and representation of process plan flexibility, and also the level of detail at which the shop floor is modelled. This framework forms a basis for a comparison of solution approaches. Published solution approaches are mostly based on the use of dispatching rules, but attempts have been made to use optimal search. The use of dispatching rules is essentially an ad hoc approach and, although relatively easy to apply in practice, produces solutions of mediocre quality. However, new research using simulated annealing suggests that neighbourhood search may offer a valuable alternative. This observation is supported by ambitious research published on the use of genetic algorithms. Because of the extreme combinatorial complexity of the combined task, optimal search methods are unlikely to be usable in practice. Furthermore, such methods exhibit a severe lack of generality because they make highly specific assumptions about problem formulation. Neighbourhood search techniques have inherent properties which give them a much higher level of generality. Although it is not an optimal search method, simulated annealing has been shown to provide solutions of significantly higher quality than those achieved by dispatching rule techniques. Also, and unlike optimal search techniques, it appears able to handle the immense complexity of the integrated planning/scheduling task. For the above reasons, it is argued that neighbourhood search techniques, such as simulated annealing, provide the best compromise available between solution quality and practical applicability.

The majority of the commercially available systems developed for capacity planning have been designedf or organisationsw hich are involved with make-to-stockm anufacturingT. heses ystemsa re difficult to implementi n bespokem anufacturing( make-to-ordero) rganisationss ince they are unable to accommodateth e requirementso f the volatile productione nvironment. This thesisi dentifies the uniqueo peratingc haracteristicos f the manufacturinge nvironmenta ssociated with bespokem anufacturingw hich caused ifficulty with the implementationo f commerciallya vailable systemsT. he findings from this investigationa re usedt o formulatea design for a capacityp lanning systemw hich fulfils the unique requirementso f the bespokem anufacturinge nvironment. The proposed system executes the capacity planning function at two separate levels of detail by integrating rough cut capacity planning with finite capacity planning. The two planning mechanisms are also integrated with a shop floor data collection system which has been designed for the assembly environment. Data interaction is achieved between the capacity planning modules and the shop floor data collection system via an Interface ManagemenSt ystem which ensurest hat the scheduled ata containedi n the individual systemsr emainsi n synchronisationa t all times. The capacity planning system also includes the design and development of a large scale display facility which is able to accommodateth e large volume of scheduled ata required to be viewed for finite capacity planning. This facility has been designed using multiple co-ordinated screens which are linked by a local area network. A data interface and parallel processing facility is incorporated in the design which enable the processing of a software application to be distributed over multiple nodes.