A tool for time, variance and energy related performance estimations in a shuttle-based storage and retrieval system

Abstract

• The mean and variance of travel time of lifts and shuttles are estimated well. • The mean energy consumption and energy regeneration per transaction are estimated. • By the provided tool, such systems’ performances can be calculated promptly. • It is the first time such an analytical-based tool for an SBS/RS is studied. • The results are highly accurate (1% APE) when compared with the simulation results. The aim of this study is to present a tool that can calculate critical performance measures of different Shuttle-Based Storage and Retrieval System (SBS/RS) designs. Specifically, our aim is to develop an analytical model-based tool that can estimate the mean and variance of travel time of lifts and shuttles, as well as the mean amount of energy consumption and energy regeneration per transaction for a pre-defined SBS/RS design. The methodology illustrated in this paper can also be utilized for any system having a straight discrete travel pattern with equal distance stop points. We are motivated in this study by a relatively new automated storage and retrieval technology, SBS/RS. By the provided tool, one can evaluate these systems’ performance promptly by changing the input design parameters (e.g., discrete travel lengths, velocity of vehicles, acceleration/deceleration of vehicles, number of tiers, number of bays, etc.) of these systems. The analytical models used in the tool are verified via simulation for several SBS/RS design scenarios. As a result, it is found that the proposed tool produces highly accurate results, specifically less than 1% Absolute Percentage Error from the simulation results.