Development of an
AGV Management System
(Original:
Desenvolvimento de um Sistema de Gestão de AGV’s)
M.Sc.
Dissertation, Faculty of Engineering of
Submitted on
Written in Portuguese.
Abstract
In the current flexible manufacturing systems (FMS), the material transportation and handling tasks on the shop floor is frequently assured by an automatic guided vehicle system (AGVS). The manufacturing system performance is very dependent on the material flow optimization in the heart of the production process. Thus, the AGVS performance is crucial in order to get a good global manufacturing system performance.
This document starts by putting in frame the automatic guided vehicle systems in the global objective of integrating and improving the flexibility of the manufacturing systems. The text proceeds with the presentation of technological aspects of an automatic guided vehicle (AGV) and with the definition of an architecture, for the management and control of an AGVS.
The design of an AGVS involves several theoretical subjects, which are studied in a systematic way in this document. It is pointed the influence of each design subject on the AGVS performance, and it is also presented known solutions for their resolution. The subjects discussed within this document are: AGVS layout design and trajectory planning, estimation of the number of vehicles required, traffic management, deadlocks, routing algorithms and scheduling algorithms for the assignment of tasks to AGVs.
The AGVS performance evaluation is inseparable from the performance evaluation of the global manufacturing system, where it is implanted. The high number of freedom degrees, the event diversity and the stochastic nature of the events occurrence in a manufacturing system, make the performance evaluation by the analytical way very difficult or almost impossible. In this context, the simulation techniques of dynamic discrete event systems are very important for the specification, design, analysis and prototyping of manufacturing systems.
Petri Nets are one of most rigorous and powerful modeling tools for event-driven systems. For this reason, Petri Nets are the experimentation basis of the research work presented and discussed within this document. It’s presented some theoretical concepts about autonomous Petri Nets, as well non-autonomous extensions of the model: synchronized, timed, interpreted, stochastic, coloured and object-oriented Petri Nets. Still in the context of Petri Nets, it’s presented a number of software tools and their essential characteristics, which make possible the Petri Nets application to the systems analysis and simulation.
Based in the AGVS architecture previously defined, it’s described the construction of a coloured and stochastic Petri Nets model for an AGVS, implanted in a flexible manufacturing system, using the Artifex software package. The simulation environment built in the Artifex enabled the execution of simulations. The AGVS and flexible manufacturing system model was simulated with different scheduling strategies, in order to study the scheduling policy influence in the global manufacturing system performance. The main experimental results, given by the simulations, are presented and discussed.
Finally, the main conclusions of the research work are pointed out.
Keywords ─ AGV, material handling systems,
architecture, Petri nets, routing, scheduling.
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BibTeX
@MASTERSTHESIS(Rocha_98,
AUTHOR = "Rui Rocha",
TITLE =
"Development of an AGV Management System",
SCHOOL = "Faculty
of Engineering of
YEAR = "1998",
MONTH = "Sep.",
NOTE = "In Portuguese"
)
Last
update: 20/06/2006
Copyright ©
2006 Rui Rocha, Dep. of Electrical and Computer Engineering,