Large-Scale Storage/Retrieval Requests Sorting Algorithm for Multi-I/O Depots Automated Storage/Retrieval Systems

Yu Bo Song,Hai Bo Mu,Luca Pancioni

doi:10.1155/2021/6646180

Yu Bo Song, Hai Bo Mu + Show 1 more

Open Access

https://doi.org/10.1155/2021/6646180

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Abstract

This paper addresses the sequence sorting problem of large-scale storage/retrieval (S/R) requests in multiple Input/Output (multi-I/O) depots automated storage/retrieval systems (AS/RS), in which the cargoes can enter/leave the system through multi-I/O depots, the stacker can load only one cargo, and the load travel time of stacker is fixed. The problem is to find an optimal sequence for a certain S/R requests sequence, and it is a special kind of traveling salesman problem. In this paper, a heuristic algorithm based on assignment is proposed. In order to eliminate the subloops emerged in the sorting process, the equivalent merging and minimum cost merging methods of subloops are considered, and the proposed algorithm is modified. Experimental results indicate the effectiveness of the proposed algorithm.

Highlights

It is challenging to quickly optimize the execution order of large-scale S/R requests sequence
E optimization methods of S/R requests sequence of the above three operation modes are discussed in single I/O depot automated storage/retrieval systems (AS/RS), in which the I/O depot is located at one end of the aisle, and each S/R request has the characteristic of periodic return to the unique I/O depot
The optimization problem of large-scale S/R requests sequence for AS/RS with multi-I/O depots is studied based on the logistics problem of actual air cargo terminal. e automated storage/retrieval system (AS/ RS) with multi-I/O depots is composed of two rows of racks, and the I/O depot is distributed along both sides of the aisle

Summary

E5 E3 E1 E4 E3 E5 E2

E other no-load travel times in SC1 and SC2 remain unchanged. erefore, when the subloops are merged, the sum of the no-load travel time of the new tour after merging is equal to the sum of the no-load travel time of subloop SC1 and SC2. e merger of more subloops without the start and end points of the stacker can be proved in the same way. E total time of no-load travels corresponding to the optimal solution of the AP, which is constituted by the start and end points of the seven load travels in Table 2 and the start and end points of the stacker, is 162.8 seconds, and three subloops are formed (see Figure 6(a)). E total time of no-load travels corresponding to the optimal solution of the AP, which is constituted by the start and end points of the nine load travels in Table 3 and the start and end points of the stacker, is 231.2 seconds, and three subloops are formed (see Figure 7(a)).

C El SC2 D

Experimental Results

Conclusions