An optimization model for command cycle assignment of AS/RS orders

Abstract

To efficiently manage inventory data and automatically manipulate storage and retrieval orders, the AS/RS has drawn attention for its powerful capability in inventory handling. Since cost and time required for inventory management should be progressively reduced in modern industries, the JIT philosophy is getting more popular in the present manufacturing environment because it allows for low or no inventory. This paper focuses on proposing an optimization model for AS/RS order assignment so that most retrieval and storage orders can be accomplished on time. In the model, the performance indices concerned are tardiness and earliness of retrieval orders and accumulation of storage orders. The decision variables to be determined are the start time and command cycle utilized for each order. According to the concept of dynamic programming, the optimization model is solved in the reverse sequence of due time for each retrieval order. A program is implemented via C‐language and an order picking example for enterprise logistics management is given to demonstrate the effectiveness of the model. It is verified that the mixed S/D command provides high flexibility to meet workload variations. The main objective of this paper is to present an effective and efficient methodology that dynamically manages inventory data and executes the AS/RS orders to fulfill the total automation of modern industries.

Key words:

• AS/RS
• dual command
• single command
• command cycle
• material