Analysis of single and dual command cycle in warehouse system with autonomous vehicle

Abstract

The paper deals with analysing the design parameters of a warehouse and various order picking conditions to arrive at the optimal warehouse design parameter and the mode of operation of the Automated Vehicle Storage and Retrieval Systems (AVS/RS) system. A ware house is characterised by the number of storage locations in the warehouse, the ratio of the length and breadth of the warehouse and the arrangement of the aisle and the cross-aisle. The AVS/RS system can be operated either in a single command cycle where either a storage or retrieval operation is carried out individually or in a dual command cycle where a storage operation is clubbed with a retrieval operation.

The paper assumes a single tier warehouse and develops expressions for calculating distances travelled for each command cycle. These expressions are used to determine the areas where the dual command cycle is better than the single command cycle for a given warehouse layout. 2 modes of order picking methods – single command cycle and dual command cycle, are analysed in order to arrive at the most efficient method of order execution for a given warehouse. Simulations are carried out for various conditions and he results obtained through simulations are verified against expressions obtained for expected distances travelled for each warehouse design.

The results indicate that the dual command cycle of order picking is the best method followed by the single command cycle for all warehouse designs and for all order picking conditions