Optimal control of warehousing systems with simultaneous crane and shuttle optimization

Considers a modern warehousing system composed of a number of aisles, each one served by a crane and sided by a pair of racks, and a shuttle which moves along a 1D path placed orthogonally with respect to the aisles' axis. The main operations performed by the control system concern the optimization of the cranes and shuttle movements. Regarding the cranes, we propose an algorithm for optimizing the sequencing of dual command (storage and retrieval) cycles, so to maximize the throughput. As for the shuttle, an algorithm is proposed to optimize the scheduling of the shuttle operations; the performance of the algorithm is evaluated and compared with the case in which no optimization is considered. A further contribution of the paper is the derivation of the model of a real warehousing system, by means of a colored Petri net approach. Such a model is then used to show and validate the effectiveness of the proposed algorithms.