Assignment of duplicate storage locations in distribution centres to minimise walking distance in order picking

Abstract

With the rapid development of e-commerce, the orders processed in B2C warehouses are characterized by heterogeneous and small volume. The traditional storage assignment strategies used in the picker-to-parts warehouses do not have advantage anymore. In this case, the scattered storage strategy is a good alternative. In this paper, we study a new scattered storage strategy which allows the same product to be placed in multiple storage locations. The correlation between products which reflects how frequently any two products will be ordered together in the same order is considered. The problem is formulated as a 0-1 integer programming model to minimize the weighted sum of distances between the products, with the weight being the elements of the correlation matrix. In order to solve large-scale problems, a GA and a basic PSO algorithm are developed. To improve solution quality, a new PSO algorithm based on the problem characteristic is designed and a hybrid algorithm combing it with GA is proposed. Experiments show that the solutions of these algorithms are close to the optimal solutions for the small-sale problems. For larger problems, the specially designed new PSO greatly improves solution quality as compared to the basic algorithms and the hybrid algorithm makes further improvement.

Implementing E-Commerce from Logistic Perspective: Literature Review and Methodological Framework

“…Many works present models and methods for storage assignment optimization [268,[273][274][275][276][277][278]. IF-warehouses are often characterized by an explosive storage policy, i.e., all items are dispersed to bins throughout the warehouse after their arrival, to reduce picking travel time [279,280]. Concerning picking optimization, e-commerce companies often use manual orderpicking systems, since they can provide the required flexibility and scalability [281].…”

Practical factors in order picking planning: state-of-the-art classification and review

“…Scattered storage imposes additional decision variables to the storage and routing models. Storage assignment is not limited to deciding on where to store an item, but also which item to store on multiple locations and where to store which quantity of an item (Anken et al 2011;Jiang et al 2020;Yang, Zhao, and Guo 2020). Moreover, when a pick list is created the routing problem defines not only the sequence in which locations should be visited, but also which location is visited to retrieve a product (Daniels, Rummel, and Schantz 1998).…”

AMR-Assisted Order Picking: Models for Picker-to-Parts Systems in a Two-Blocks Warehouse

“…In the second case, however, after a picker has collected all the items of a certain order in her/his area, those are transferred to the next area, typically by means of conveyors; in the situation described, therefore, items of the same order are already grouped together. Several authors have studied the optimization of a warehouse organized in zones [7]. The choice of the optimal number of zones to divide a manual warehouse was analyzed in [8,9], with the aim of minimizing the collection time.…”

“…Constraint (5) define the order picker's start time of picking the batch items stored in her/ picking sub-aisle. Constraints ( 6) and (7) guarantees that the order picker cannot hand over the picked items to the appropriate AMR until (i) she/he has returned to the handover location with these items (see Constraint ( 6)), and (ii) the AMR has arrived at her/his handover location (see Constraint (7)). Constraint (8) determine the arrival time of the AMR handling batch b ∈ B at each handover location j ∈ V. Inequalities (9) guarantee that two batches do not overlap and ensure feasibility with respect to time.…”