Scheduling twin automated stacking cranes for job assignment at automated container terminals

This paper investigates a problem of scheduling twin automated stacking cranes (ASCs) for job assignment at an automated container terminal with a new yard layout, in which the handover areas at two-end of a yard block have the same function for transferring containers between ASCs and automated lifting vehicles. This problem is to assign container jobs to twin ASCs and sequence these assigned jobs, and it is formulated as a mixed-integer linear programming model to minimize the sum of the makespan and the total job tardiness (or delay time). For solving the medium- and large- sized cases, a new hybrid algorithm named Dividing, Resequencing and Exchanging (DRE) is designed and consists of the dividing procedure, the model for the extended assignment problem and the improved adaptive large neighborhood search algorithm. Numerical experiments demonstrate the efficiency and effectiveness of the proposed model and algorithm, and show the great influence of the ASC speed on the problem objective.