Analysis of automated guided vehicle configurations in flexible manufacturing systems

Automated guided vehicle (AGV) systems complement the operation of flexible manufacturing systems (FMS) by providing integrated automated material han dling that capitalizes on the system's flexibility. Previous research consi dering AGV systems for use in FMS installations has focused on complex cont rol strategies to reduce the congestion problem often encountered in these systems. Recently, attention has been given to tandem system configurations that reduce congestion and simplify system control. The present study uses the simulation methodology to compare the performance of three AGV configu rations under a variety of experimental conditions. The results indicate th at system size, load/unload time, and machine failure rate factors have sig nificant impacts on the operation of the systems considered. In general, wi th respect to due date performance, it is recommended to use the traditiona l configuration in small systems while using the tandem/loop configuration in larger systems. Furthermore, it is shown that the addition of the loop t o the tandem configuration mitigates the sensitivity of the tandem configur ation to the load/unload time factor as well as significantly improving its performance under high load/unload times. Thus, if tandem configuration is desired to reduce congestion and simplify system control, investments must be made to directly reduce the load/unload times or to construct a loop to avoid the load/unload time penalty.