Network configuration and machine layout in fixed-path material handling systems

In this paper, we address a difficult combinatorial problem that arises in designing fixed-path material handling systems, where handling occurs over a pre-defined and fixed route which connects various "sites" that are represented by a unique set of pickup and deposit points. Examples of such systems include power-and-free conveyors, monorails, in-floor towline conveyors, and automated guided vehicle systems. The objective of this study is to determine an efficient system design by simultaneously considering the configuration of the fixed path and the layout, i.e., the processor (or machine) assigned to each site. Past studies in this area have focused either on optimizing the path configuration for a given layout or on optimizing the layout for a simple path configuration. In this study, we show how simulated annealing can be applied to obtain good solutions to the problem when both the path configuration and the processor locations are determined concurrently. Since the above two problems are closely related, significant savings can be achieved by considering them simultaneously.