Robotic Compact Storage and Retrieval System (RCS/RS) is a contemporary robots-to-pickers solution designed to enhance operational efficiency and space utilization in warehouses. The system employs multiple robots navigating a grid along the x- and y-axes, while performing storage and retrieval operations along the z-axis. Within this system, retrieving a bin involves first removing the bins stacked above it. Then, depending on the storage policy, the displaced bins are either returned to one level below their original locations before the target bin is delivered to a port, or restored to their original locations after the target bin is processed at the workstation and returned. However, sequential removal of stacked bins to reach lower levels results in a notable limitation, while restricting system height reduces space utilization efficiency and increases operational effort in high-rise configurations. This study develops an analytical model for evaluating operational time within RCS/RS under constant motion conditions and investigates the effects of storing and retrieving bins in groups of two or three. The results indicate that system performance depends significantly on the number of bins handled. The proposed computational framework enables warehouse service providers to evaluate the trade-offs between space utilization and operational time associated with storing and retrieving bins collectively. It also contributes to optimizing RCS/RS configurations to achieve improved space efficiency and operational performance.

Keywords

Logistics, Intralogistics, Warehousing, Compact systems, Operation time modeling, Optimal system configuration