The impact of item weight on travel times in picker-to-parts order picking: An agent-based simulation approach

In picker-to-parts order picking the traveling of the order picker between the storage locations account for approximately 50 % of the overall time. Reducing travel times can therefore substantially improve the productivity. Hereby, current research has almost exclusively focused on minimizing the travel distance and assumed a constant velocity of the order picker. However transported item weight can significantly influence the velocity and consequently travel times as well. Hence, the paper at hand analyzes to which extent travel times vary in dependence of item weights in the warehouse. New weight class based storage assignment policies are investigated. Their aim is to locate the items in the storage area according to their weight so that the heaviest items are collected at the end of the order picker's tours. Agent-based simulation experiments confirm that the new policies can significantly reduce travel times.