The operation of an automated guided vehicle system in a manufacturing job shop
Abstract
The subject of this thesis is the operational aspects of an automated guided vehicle (AGV)-based transport system serving a job shop-type manufacturing system. Automated guided vehicles provide higher levels of flexibility and computer integrability and are considered an ideal transport method for the factories of today and tomorrow. However, the installations are limited in number mainly due to high costs of initial investment and the complexity involved in the operation. The main objective of this research is to alleviate these problems by getting a better understanding of the operational aspects of an AGV-based factory transport system and by proposing alternative methods for operational control. Two of the major issues in the operation of an AGV system considered in this research are path planning and vehicle dispatching. The path planning problem is to find a path for a vehicle which is assigned a transport task. In particular, the operation of a bidirectional AGV system is seriously considered in this research since a bidirectional system is intuitively more attractive than its unidirectional counterpart in terms of vehicle efficiency. An algorithm for finding conflict-free shortest-time paths for vehicles moving in a bidirectional flow path network is proposed. A myopic conservative strategy for cooperative path planning to coordinate the movements of several vehicles is also proposed. The vehicle dispatching problem is to assign vehicles to transport demands. Of particular interest is the control of material flow and the dispatching of AGVs in a job shop without a central work-in-process storage to eliminate the need for and save the costs to install and operate such a facility. An interesting issue in the control of material flow in a job shop is the prevention and resolution of shop deadlocks. A heuristic vehicle dispatching procedure with an embedded deadlock prevention method is proposed.
Degree
Ph.D.
Advisors
Tanchoco, Purdue University.
Subject Area
Industrial engineering
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