GridPick: A High Density Puzzle Based Order Picking System with Decentralized Control

Abstract

We develop a novel semi-automated order picking system called GridPick that enables high levels of throughput, space usage, and flexibility. The system uses unit sized conveyor modules in grid architecture to bring requested items to and away from the pick face dynamically and as needed to fulfill orders to the system. GridPick uses a message passing and negotiation algorithm with decentralized control rules, which is a relatively unexplored area in conveyor-based material handling systems. In the second part of the dissertation, we modify the GridPick system to allow picking from two sides of the grid. This enhancement allows higher throughput and an improved use of space when compared with single sided, traditional systems. To investigate structural properties of the system, we present a Petri Nets model. We use the model to verify deadlock conditions for the single-sided version of GridPick. We show that the system is deadlock free for up to a 4X4 grid and conjecture that the general case is also true.