On storage assignment policies for unit-load automated storage and retrieval systems

This paper focuses on the management of automated storage and retrieval systems (AS/RS) from a practical standpoint. Most of the articles in the recent AS/RS literature rely on analytical models that are based on tight assumptions. However, some of these assumptions are not clear cut and therefore the validity of the results reported in the theoretical works need to be clearly assessed when applying them to a particular industrial setting. To this end, this paper presents a discrete-event simulator that was designed to accurately reproduce the characteristics of an industrial AS/RS owned by a large manufacturer in the food industry located in Quebec City, Canada. Various scenarios inspired by real data provided by our industrial partner were used to compare the system performance under several storage assignment policies. Our experimental results confirm our hypothesis that the system behaviour deviates from the theoretical expectations as soon as the most simplistic, yet realistic conditions are considered.