A Simulation Software Tool for Order Picking in a Person-Aboard Storage/Retrieval System

A software tool is developed to simulate a person aboard automated storage/retrieval vehicle in an order pick system. The program allows the calculation of the travel time of the storage/retrieval vehicle depending on different item and order patterns, storage assignment strategies, batching methods, and routing algorithms. It consists of a set of modules, which can be extended to model a wider variety of order pick systems. The included modules allow the simulation of a rectangular warehouse with several pick aisles and cross aisles; the numbers of pick and cross aisles are under user control, and a sketch diagram is generated as a result. Items and orders are generated using a number of distributions included in the Microsoft Excel Visual Basic software. Storage assignment methods are included that perform the bin assignment based on item activity: unsorted, active items near cross aisle, active items near pick aisle, active items near I/O point, and table driven. The batching methods comprise the first-come-first-serve (FCFS) and the sequential minimum distance (SMD) method. The closest neighbor heuristic is available as an intelligent routing method. The entire program is coded in Microsoft Excel Visual Basic. Two example applications of the software are given at the end.