Job shop Scheduling with Alternative Machines in FMS

Sang Hyoup Lee

Flexibility in FMS is a key issue that has drawn increasing attention. We consider the operational scheduling problem and the determination of production routing simultaneously in this paper. The purpose of this research is to develop Mixed Integer Linear Programming(MILP) formulations for a general job shop system with alternative machine routings. We consider four performance measures: mean flow time, makespan, maximum lateness, and total absolute deviation from due dates. The MILP formulations can be used either to compute optimal solutions for small size problems or to test the performance of the existing heuristic algorithms. In addition to the MILP formulations, we have also developed heuristic algorithms for the minimization of makespan.