Combined scheduling rules in FMS via simulation and an analytical hierarchy process

Many quantitative methods have been developed in an attempt to acknowledge uncertainty in decision making and to manage the inherent risk during economic planning for new technology implementation. This paper outlines a relatively simple and practical risk analysis, accompanied by implementing combined scheduling rules in flexible manufacturing systems (FMS). It employs the proven analytical hierarchy process (AHP) coupled with confidence intervals from data gathered through simulation modelling techniques. Simulation models were developed using a software package SIMFACTORY II.5, which is based on the concept of visual interactive simulation. The purpose of the present simulation is to analyse various combinations of scheduling rules in the FMS system, i.e. given a set of scheduling rules applied at the workstations, the effect of different scheduling rules at the input loading buffer to the system performance are studied. Various measures, such as throughput, utilisation, lateness, etc., are examined. An AHP multiattribute analysis is performed by using a decision support software package, AUTOMAN. This package evaluates and combines the qualitative and quantitative factors for different scheduling rules.