Solving a time constrained two-crane routing problem for material handling with an ant colony optimisation approach: an application in the roof-tile industry

Abstract

This paper presents an ant colony optimisation (ACO)-based solution approach for a real-world two-crane routing problem, where a number of different load carriers must be moved within a given cycle time by two gantry cranes in a continuous production process for roof tiles. The cranes have to transport the roof-tile batches and to return the load carriers and intermediate pads for subsequent batches. A feasible solution has to observe workflow-, space-, collision-, and machine-cycle constraints. The objective is to find a feasible schedule that minimises the working time for both cranes. The authors compare different solution approaches in terms of learning – and visibility strategies based on ACO in extensive numerical studies. A visibility concept is used to both partition and balance workload between the cranes.

Keywords:

• two-crane routing problem
• ant colony optimisation
• stacker crane problem
• crane scheduling
• gantry crane

Acknowledgement

The authors would like to thank Kathryn A. Dowsland for her useful comments on this contribution.