Optimizing Container Movements Using One and Two Automated Stacking Cranes

摘要

The number of containers shipped through ports has increased substantially in recent years and has stimulated research and development of ways to improve storage yard operations. The productivity of a port's storage yard depends, in part, on the cranes that are working in storage blocks. Each crane follows a route described primarily by the order to move each container that enters or leaves a block and the position to stack each container in the block. Each container that leaves (enters) the block must be unloaded (loaded) in a limited capacity transfer point before (after) a given time. This thesis is the first to develop Integer Linear Programs (ILPs) to prescribe routes for one and two equal sized Automated Stacking Cranes (ASCs) in a single block working with straddle carriers to load and unload containers from the transfer points. Using real world data, we construct test problems varying both the number of container bays (length) and excess capacity of each block. We find one ASC working alone over four hours requires up to 70% more time than two ASCs working together to accomplish the same required container movements. ILP solution time is typically only a few seconds.