Optimization of Unidirectional Material Handling System with Short-Cut

Abstract

Unidirectional circulation-type material handling system on a single loop with a shortcut is a typical and basic unit in a flexible manufacturing system (FMS). It is widely used in the FMSs. Superposition efficiency of the basic unit often determines the one of the whole system. In this system, a fleet of AGVs circulates along a loop with short-cut unidirectionally. After AGVs load jobs, jobs are sent to process at a processing station set along the path, and then unload at an unloading station. AGVs continue to circulate until all jobs are processed. The AGVs can't be overtaken except in the cross point. So it is difficult to avoid the interference between AGVs. Different scheduling rules have an important effect on the unidirectional circulation-type material handling system on a single loop with a shortcut. To decrease the interference and improve performance of the system, this paper makes a mathematical model of this system and put forward optimal scheduling rules. Experiment results show that the optimal rules can decrease the interference time and improve efficiency, so as to achieve the optimal performance.