Travel Time Analysis of Split-platform Automated Storage and Retrieval Systems with Two Storage Classes

Abstract

In recent years, a new kind of automated storage and retrieval systems (AS/RS) called split-platform AS/RS (SP-AS/RS), has been studied by researchers. The SP-AS/R system consists of vertical and horizontal platforms, which move independently. This paper studies the performance of a two-class-based storage policy for such systems. We formulate the expected travel time of an arbitrary unit load for a two-class-based SP-AS/R system and compare the performance of our proposed two-class based storage policy with random storage. The numerical results show that our two-class-based storage policy can significantly reduce the expected travel time of an SP-AS/R system compared to random storage (up to 63.92%) for the instances tested.