Article ID: | iaor19991735 |
Country: | Netherlands |
Volume: | 103 |
Issue: | 3 |
Start Page Number: | 515 |
End Page Number: | 530 |
Publication Date: | Dec 1997 |
Journal: | European Journal of Operational Research |
Authors: | Rethmann J., Wanke E. |
This paper presents the theoretical foundations for controlling pile-up systems. A pile-up system consists of one or more stacker cranes picking up bins from a conveyor and placing them onto pallets with respect to customer orders. The bins usually arrive at a conveyor from an orderpicking system. We give a mathematical definition of the pile-up problem, define a data structure for control algorithms, introduce polynomial time algorithms for deciding whether a system can be blocked by making bad decisions, and show that the pile-up problem is in general NP-complete. For pile-up systems with a restricted storage capacity or with a fixed number of pile-up places the pile-up problem is proved to be solvable very efficiently.