13 - Energy efficient automated warehouse design

Abstract

The aim of this work is to study an automated warehousing system design to optimize significant performance metrics: energy and travel time related performance metrics in the system. Different from the literature, we study a specific design of a well-known automated warehousing system, shuttle-based storage and retrieval system (SBS/RS), in which shuttles can travel between tiers by using a lifting mechanism installed at periphery of racks. In a traditional SBS/RS design, shuttles are dedicated in each tier that is tier-captive. They perform horizontal travel for storage and retrieval of loads within a tier of an aisle. There is a single lifting mechanism in each aisle for vertical travel of loads. These systems are mostly utilized in large distribution centers to obtain high transaction rate for storage and retrieval processes. In a traditional design, because there is a dedicated shuttle in each tier of an aisle and a single lifting mechanism in each aisle, lifts are mostly bottleneck and the utilization of shuttles are very low. Hence, a new design with a few numbers of shuttles that can travel between tiers might be promising in decreasing the initial investment cost and increasing the utilization levels of shuttles. In this work, we explore an optimal warehouse design for that new SBS/RS concept—tier-to-tier SBS/RS—in terms of number of shuttles, number of tiers, aisles, acceleration/deceleration values of lifts/shuttles, etc. to improve some significant performance metrics from the system (e.g., energy consumption and cycle time per transaction).