In recent years, the worldwide competition and the growing demand for a high variety of products have emphasized the role of production systems. In particular the FMSs are of increasing importance because they have the capability to face changes in production environment and to combine the efficiency of the mass-production lines with the flexibility of job-shops producing a variety of products in small- or medium-size batches. In any FMS, control software plays a key role since it can allow optimization of both hardware (numerically controlled machines, material handling devices, buffers, etc.) and software (information flow, data base content, etc.) | 1 System Approach to the Design of Generic Software for Real-Time Control of Flexible Manufacturing Systems FMS Preface Dedication Introduction Fundamental Steps of the Modeling Process Specification of the Model Static Structure Workstations Transport System Queuing Network Configuration Production Activity Configuration Job Configuration Server Configuration Transport System Configuration Definition of the Queuing Network Configuration Scheduling Policy The Discrete Event Dynamic System Model Maria Pia Fanti Events The DEDS Model Politécnico di Bari Bruno Maione An Example of How the Modeling Process The Model Static Structure of the Application Example The Queuing Network Configuration of the Application Politécnico di Bari Example The Applied Scheduling Policy Giacomo Piscitelli The Generic Control Software Organization Politécnico di Bari The Control Hierarchy Objects and Architecture of the Control Software Biagio Turchiano Conclusions Politécnico di Bari Appendix List of Principal Symbols 2001 by CRC Press LLC Preface The control system is the core of any flexible manufacturing system FMS because it confers to the plant the capability to absorb internal changes and external fluctuations in demand and in production environment. However the technical literature has repeatedly documented that poor control software design is the major source of difficulties in implementing FMSs. Namely the FMS potentiality is not yet fully utilized because typical contemporary control software packages are still proprietary and do not possess flexibility and genericity. On the contrary reducing the programming and reprogramming effort needs a generic software usable in an arbitrary FMS producing an arbitrary part mix. To design a generic software two main problems must be solved. The former is to define an abstract formalism representing both hardware software components of the FMS and the production plans. The latter consists in
