A Timed Petri Net Model For The Quay Crane Scheduling Problem

This paper deals with the problem of constructing the schedule for the operations of a group of quay cranes devoted to discharge/load a set of groups of containers from a vessel at a maritime container terminal. The schedule is constructed starting from the assignment of each individual group of containers to a quay crane under the goal of minimizing the overall vessel completion time, aka the makespan. The assignment is provided, e.g., by the search process of an optimization algorithm designed for solving the so called quay crane scheduling problem. In this paper, a novel Timed Petri Net model is proposed to construct the schedule from a given assignment. As a novelty, the proposed model considers the initial and final location of the quay cranes to ensure that some necessary physical constraints are satisfied during the idle periods. It also defines an easy-to-implement set of rules to construct the schedule such that the makespan is minimum.