(A) study on dispatching algorithm for automated guided vehicle systems using data envelopment analysis

Abstract

Automated Guided Vehicle Systems(AGVSs) have emerged as an important part of material handling in Flexible Manufacturing Systems(FMSs). This is due to the fact that AGVS provides the flexibility and adaptability required from material handling systems in FMS environment. This thesis deals with dispatching algorithms which are recognized as a key element for efficient operations of AGVS. This thesis develops a new AGV dispatching algorithm based on a bidding concept and data envelopment analysis(DEA). In the suggested algorithm, the information of work-in-process(WIP) in incoming and outgoing buffers of each workstation, and the travel time to the workstation of an AGV become input parameters of mathematical functions. These functions will be called "bidding functions". To integrate the values coming from these bidding functions, "dispatching function" is suggested which provides a basis for the selection of the most urgent among competitive move requests. Without pre-assigning weights to performance measure , DEA evaluates the efficiency of each dispatching function relative to the other functions. The performance of the new dispatching algorithm with DEA weight is compared with some well-known existing rules in terms of the system throughput through simulation on a hypothetical job shop type manufacturing system.