A Mathematical Model for Supermarket Order Picking

2014

Warehouses' management is becoming more important inside the logistics' world lately, an optimal management implies a working time reduction and it leads to a cost reduction. The objective of this thesis is to discover the world of warehouses' management, and especially the warehouse order picking field. For that reason it will be divided into two parts. The first one will be theoretical, and the goal is to acquire a theoretical base. The second one will be more practical, firstly a statistical analysis will be carried out through a factorial design in order to understand the performance of the different routing strategies and when is better to use each. Secondly, the relationship between the response and the travel time will be studied through a correlation study.

International Journal of Simulation Modelling, 2020

Order picking (OP) is a process that occurs in warehouses of unitized goods and it includes all activities that follow the retrieval of demanded goods, according to demanded type and quantity, with the intention of meeting customer demands, accurately and on time, with acceptable costs. As the OP process can contribute up to 50 % to the overall warehouse operational costs, design of the order picking system (OPS) needs special attention during the warehouse design process. In existing systems, the need for improvement is often caused by the change in demands. This paper analyses the possibilities of low-level picker-to-part OPS improvement through appropriate decision making on different design levels: tactical and operational. In this paper, a simulation-analytical model is developed to evaluate different OPS scenarios based on three storage assignment policies, four routing strategies and two different OP methods. Two layout variants and the evaluation of the required workforce are considered as well. The experiment results indicate that the application of the proposed model could lead to significant improvements regarding OPS performances and resource utilization.

Economic Research-Ekonomska Istraživanja, 2018

The revolution of information brought new possibilities for the business organisations: new management methods for managing supply chains, logistic processes and warehouses appear as well as innovative process management methods in the sense of knowledge management. The order picking process in the warehouse should be emphasised as one of the most laborious activities, since it consumes $55% of the warehouse labour activities. This study pays special attention to the order picking process in a very-narrow-aisle (V.N.A.) warehouse, with the aim to identify solutions for the reduction of total travel distance and costs. The methods of the scientific literature analysis and synthesis simulation were applied. The results of the simulation confirmed the application of a pick-by-article strategy that is implemented with 'seed' sorting by order solution in low-income countries.

From literature review and deep understanding on the practical industry, it is understood that the proper use of storage assignment policies can use minimum storage space to reach the purpose of minimum total traveling distance, and this has a direct impact on enhancing the order picking performance. At the same time, proper routing planning can minimize overall order picking cost, and finally reach the goal of picking performance enhancement in unit time. Therefore, this paper considers the effects on the order picking system performance for factors such as quantity and layout type of cross aisles in a warehouse system, storage assignment policy, picking route, average picking density inside an aisle, and order combination type, etc. A software, eM-plant, will be used as a simulation and analysis tool, a warehouse design database will be developed, which is based on the minimum overall traveling distance as the optimum performance index, the cross aisle quantity, warehouse layout, storage assignment, picking route planning, picking density and order combination type will be optimally integrated and planned in the warehouse system. Finally, we provide this database to the industry as a reference in the warehouse planning or warehouse design improvement in the future.

Innovative Applications in Smart Cities, 2021

This chapter explores the relationship among different routing policies for order picking and the features of the problem (describing both warehouse layout and orders), the results obtained by simulation show that some policies are especially sensitive to the presence of certain conditions that are likely to be present in real-world cases. Moreover, the routing policies are represented for the first time in the literature as far as our knowledge-on structured algorithms. This contribution can facilitate their implementation because the features of the policies are modeled by formal mathematical structures, laying the foundations to standardize the way they operate.

We present a two-phase model for planning and scheduling of order picking processes. In many warehousing environments order picking processes are organized according to the pick&pack principle. Pickers must build stabile loads during the picking process under strict time constrains. A genetic algorithm with Pareto elitist-based selection has been developed for this multi-criteria optimization problem. The resulting order pick lists are the input of the scheduling module. Starting times of the lists are determined with simulation optimization techniques considering time constrain, labor and earliness/tardiness penalty costs, and utilization grades. Costs of order picking can reach as high as fifty percent of all warehousing costs. Travel times consume almost half of a complete order picking tour. So there is always a need to optimize order picking processes.

European Journal of Operational Research, 2001

This paper considers a parallel aisle warehouse, where order pickers can change aisles at the ends of every aisle and also at a cross aisle halfway along the aisles. An algorithm is presented that can find shortest order picking tours in this type of warehouses. The algorithm is applicable in warehouse situations with up to three aisle changing possibilities. Average tour length is compared for warehouses with and without a middle aisle. It appears that in many cases the average order picking time can be decreased significantly by adding a middle aisle to the layout.

Applied Sciences

Companies have been trying continuously to reduce their logistics costs in the current competitive markets. Warehouses are important components of the logistics systems and they must be managed effectively and efficiently to reduce the production cost as well as maintain customer satisfaction. Order-picking is the core of warehouse operations and an order-picking system (OPS) is essential to meet customer needs and orders. Failure to perform the OPS process properly results in high costs and customer dissatisfaction. This research aims to investigate the state of the art in the adoption of OPS and provide a broad systemic analysis on main operating strategies such as simultaneous consideration of order assignment, batching, sequencing, tardiness, and routing need. This study reviews 92 articles, classifies combinations of tactical and operational OPS problems, and provides guidelines on how warehouse managers can benefit from combining planning problems, in order to design efficient...

European Journal of Operational Research, 2014

Space required for the order picking area and labor required to perform the picking activity are two significant costs for a distribution center (DC). Traditionally, DCs employ either entirely wide or entirely narrow aisles in their picking systems. Wide aisles allow pickers to pass each other, which reduces blocking, and requires fewer pickers than their narrow-aisle counterpart for the same throughput. However, the amount of space required for wide-aisle configurations is high. Narrow aisles utilize less space than wide aisles, but are less efficient because of the increased likelihood of congestion experienced by pickers. We propose a variation to the traditional orthogonal aisle designs where both wide and narrow aisles are mixed within the configuration, with a view that mixed-width aisles may provide a compromise between space and labor. To analyze these new mixed-width aisle configurations, we develop analytical models for space and travel time considering randomized storage and traversal routing policies. Through a cost-based optimization model, we identify system parameters for which mixed-width aisle configurations are optimal. Experimental results indicate that annual cost savings of up to $48,000 can be realized over systems with pure wide or narrow aisle configurations.

Order picking is the warehousing process by which products are retrieved from their storage locations in response to customers' orders. Its efficiency can be influenced through the layout of the area and the operating policies. We present a model that minimizes travel distances in the picking area by identifying an appropriate layout structure consisting of one or more blocks of parallel aisles. The model has been developed for one commonly used routing policy, but it is shown to be fairly accurate for some other routing policies as well.