Multi-Crane Scheduling in Batch Annealing Process

Abstract

This paper addresses a multi-crane scheduling problem that incorporates scheduling shared two-category limited number of machines motivated by batch annealing process (BAP) in the iron and steel factory. In this process, each coil subjects to a long heat-treatment cycle by varying the temperature within furnace (machine) and cooler (machine) which are operated by crane orderly. The objective is to minimize the annealing completion time of the last coil (make span). We propose a two-phase heuristic algorithm which consists of assignment and scheduling. Based on a dynamic programming, the assignment phase is to assign each crane to its exclusive sub-block, followed by machine assignment to each sub-block. Scheduling phase adopts an earliest requirement operated stage first strategy. Finally, the effectiveness of the proposed algorithm is theoretically analyzed from an absolute performance point of view.