Applications Of Petri Nets In Manufacturing Systems

Modeling and control issues in automated manufacturing systems. Introduction to Markov processes and queueing theory. Petri net theory in manufacturing. Formal definitions, classification, and properties of ordinary petri nets. Analysis of petri nets. Timed, stochastic, and generalized stochastic petri nets. Performance analysis of automated manufacturing systems using petri nets. Petri net modeling and real-time controllers.

One critical barrier leading to successful implementation of flexible manufacturing and related automated systems is the ever-increasing complexity of their modeling, analysis, simulation, and control. Research and development over the last three decades has provided new theory and graphical tools based on Petri nets and related concepts for the design of such systems. The purpose of this book is to introduce a set of Petri-net-based tools and methods to address a variety of problems associated with the design and implementation of flexible manufacturing systems (FMSs), with several implementation examples.There are three ways this book will directly benefit readers. First, the book will allow engineers and managers who are responsible for the design and implementation of modern manufacturing systems to evaluate Petri nets for applications in their work. Second, it will provide sufficient breadth and depth to allow development of Petri-net-based industrial applications. Third, it will allow the basic Petri net material to be taught to industrial practitioners, students, and academic researchers much more efficiently. This will foster further research and applications of Petri nets in aiding the successful implementation of advanced manufacturing systems.

Driven by the request for increased productivity, flexibility, and competitiveness, modern civilization increasingly has created high-performance discrete event dynamic systems (DEDSs). These systems exhibit concurrent, sequential, competitive activities among their components. They are often complex and large in scale, and necessarily flexible and thus highly capital-intensive. Examples of systems are manufacturing systems, communication networks, traffic and logistic systems, and military command and control systems. Modeling and performance evaluation play a vital role in the design and operation of such high-performance DEDSs and thus have received widespread attention from researchers over the past two decades. One methodology resulting from this effort is based on timed Petri nets and related graphical and mathematical tools. The popularity that Petri nets have been gaining in modeling of DEDSs is due to their powerful representational ability of concurrency and synchronization; however these properties of DEDSs cannot be expressed easily in traditional formalisms developed for analysis of `classical' systems with sequential behaviors. This book introduces the theories and applications of timed Petri nets systematically. Moreover, it also presents many practical applications in addition to theoretical developments, together with the latest research results and industrial applications of timed Petri nets. Timed Petri Nets: Theory and Application is intended for use by researchers and practitioners in the area of Discrete Event Dynamic Systems.

Using formal methods for the specification and verification of hardware and software systems is becoming increasingly important as systems increase in size and complexity. The aim of the book is to illustrate progress in formal methods based on Petri net formalisms. It presents both practical and theoretical foundations for the use of Petri nets in complex system engineering tasks. In doing so it bridges the gap between Petri nets and the systems modeling and implementation process. It contains a collection of examples arising from different fields, such as flexible manufacturing, telecommunication and workflow management systems.

Petri Net Synthesis for Discrete Event Control of Manufacturing Systems develops two essential resource-sharing concepts: parallel and sequential mutual exclusions and theoretical results in Petri synthesis. A parallel mutual exclusion (PME) is defined to model a resource shared by independent distributed processes, and a sequential mutual exclusion is a sequential composition of PMEs, modeling a resource shared by sequentially-related processes. A hybrid synthesis methodology for Petri net models and controllers is proposed using top-down, modular, and bottom-up design ideas and the mutual exclusion theory. An aggregate Petri net model is refined by replacing places and /or transitions with basic design modules which are mathematically and graphically described. Petri net design methods are presented for such buffers as automatic storage and retrieval systems. Using the proposed method synthesizes both Petri net structure and feasible initial markings, guaranteeing that resulting Petri nets have desirable system properties such as freedom from deadlock and cyclic behavior. A Petri net controller is extended to error recovery for automated manufacturing systems. The theory can guarantee that the desired system properties achieved by the original design will be preserved when the controller is augmented to deal with an error in the prescribed methods. Control code has been directly generated from Petri net definitions. The algorithm and implementation details are given for a flexible manufacturing system. Using the approach presented in Petri Net Synthesis for Discrete Event Control of Manufacturing Systems, engineers and research workers can develop their own discrete event control applications and experiments.

M. Silva Significant changes have been occurring in industrialized countries since the Second World War. Production is moving towards sophisticated high qUality products, economy of scale has been replaced by economy of scope, jerky demands are progressively replacing steady demands, and competi tiveness is becoming a worldwide phenomenon. These trends require highly automated manufacturing systems with small set-up times and high flex ibility. As a consequence, implementation and running costs of modem manufacturing systems are drastically increasing, whereas their fields of application remain limited, and every day become even narrower, which increases the risk of early obsolescence. This is the reason why designers are trying to improve the preliminary design phase, also known as the 'paper study phase'. The preliminary design phase includes, but is not limited to, the func tional specification, and the evaluation of the system. Many tools exist to support the functional specification of manufactur ing systems. IDEFO is one of these tools. It leads, using a top-down ap proach, to a precise functional description of the required system. However, its use cannot be extended further. In general, the evaluation starts with a modeling step, which depends on the evaluation tool used, and ends by applying the model to find out its main dynamic characteristics. Two main approaches can be used to perform this task, namely simulation and math ematical approach. Using simulation, the modeling tool is either a classical computer language, or a simulation language.

The world is full of events which cause, end or affect other events. The study of these events, from a system point of view, is very important. Such systems are called discrete event dynamic systems and are of a subject of immense interest in a variety of disciplines, which range from telecommunication systems and transport systems to manufacturing systems and beyond. There has always been an intense need to formulate methods for modelling and analysis of discrete event dynamic systems. Petri net is a method which is based on a well-founded mathematical theory and has a wide application. This book is a collection of recent advances in theoretical and practical applications of the Petri net method and can be useful for both academia and industry related practitioners.

This book concentrates on the applications of Petri Nets in manufacturing. Petri Nets are graphical and mathematical tools, and the synchronism of executed actions is the natural phenomenon because of which Petri Nets are considered as mathematical tools for modeling synchronous systems. The primary idea of this theory was modified by several researchers according to their needs, owing to the odd "flexibility" of this theory. The theory is still cultivating and some directions of investigations are also encompassed in this book.