A Clustering-based Method for Sequencing Quadruple Command Cycles of Twin-Shuttle AS/RS

摘要

Continuing need for high-throughput automated storage and retrieval systems (AS/RS) introduced storage/retrieval (S/R) machines that can carry more than one unit-load. However, this technology involves larger capital investment and careful operating methods are desired that make most of its capability. In this paper, we study an improved sequencing method for the twin-shuttle (or double-shuttle) AS/RS performing quadruple command cycles. The proposed method employs a clustering algorithm combined with a dynamic programming method to find an optimal sequencing within each cluster. We report simulation results comparing this method favorably with the Nearest Neighbor heuristic which is commonly used in the literature.