Optimal scheduling for an automated m-machine flowshop

Abstract

This paper considers a scheduling problem of minimizing the maximum completion time (i.e., the makespan) for an automated flowshop manufacturing system such as FMS which consists of m machining cells with sufficient buffers, an AGV (automated guided vehicle) and loading/unloading stations. For this problem we propose a heuristic algorithm based on a fuzzy approximation (called fuzzy scheduling), and a branch-and-bound algorithm with fuzzy inferences. Computational experiences show that the fuzzy scheduling can give optimal or near optimal solutions in very short time, and the branch-and-bound algorithm can efficiently give optimal solutions to problem instances with three-machines and up to 400 parts with high probability over 90%.