A study on an outbound problem of four-way shuttle system by considering unrestricted relocation and duplicate priority

• 1、School of Evergrande Management, Wuhan University of Science and Technology, Wuhan 430065, China
• 2、School of Economics and Management, University of Electronic Science and technology, Chengdu 610000, China
• 3、School of Technology, Beijing Forestry University, Beijing 100083, China
• 4、Hubei Puluoge Technology Co., Ltd, Wuhan 430065, China

Abstract：Four-way shuttle storage and retrieval system is an efficient intensive storage system, in accordance with the order of goods out of the warehouse to pick up the goods, due to the structure of the system multi-depth position characteristics, may result in a new blockage caused by additional box. In order to further shorten the outgoing time, enterprises usually divide the goods without strict time window restrictions into a group and do not distinguish the order of picking up the goods, the same picking up order of the goods is known as duplicate priority. For the four-way shuttle storage and retrieval system considering the duplicate priority of the unrestricted relocation problem, this paper proposes an exact algorithm using iterative deepening branch and bound to obtain the minimum number of required relocations.By comparing the experimental results, the validity of the iterative deepening branch-and-bound algorithm was verified from the two dimensions of time and the number of bin-searching operations in comparison with the improved A* algorithm and the heuristic algorithms commonly used in enterprises. The results demonstrate that the algorithm proposed in this paper can yield the optimal bin-searching scheme within a short period, further enhancing the outbound efficiency of goods.

Keywords： Four-way shuttle warehouse duplicate priority unrestricted relocation brand and bound algorithm