Document Type

Research Paper

Publication Date



In the last years, new solutions for order picking systems have been developed both from industry and academics, especially for small items. They include innovative flexible automatic parts-to-picker systems and optimized picker-to-parts ones. One of these solutions consists in the use of Vertical Lift Modules (VLMs), a storage column in which small items are stored in extractable trays. In this paper, we study a new system composed by dual-tray VLMs where the operators perform picking and sorting activities. We propose several actions in order to improve the productivity of the entire system: 1) class based storage assignment of items inside the VLMs; 2) batch retrievals of items and 3) batch orders and batch retrievals with pick-and-sort activity. The impacts of these actions are evaluated with a simulation of the system using real data from an industrial case


Paper 4

Publication Title

Progress in Material Handling Research: 2016