Optimisation of yard crane scheduling considering velocity coefficient and preventive maintenance

This paper develops a mixed integer programming model to formulate the multiple yard cranes scheduling problem (YCSP) in container terminals. The model performs a given set of jobs with different ready times in a yard zone, considering yard cranes interference. Both preventive maintenance and velocity coefficient for yard cranes are considered in this model, which makes it more realistic and applicable. The proposed model aims to minimise the mean completion time of total jobs and minimise the maximum completion time among the yard cranes. Due to NP-hardness of proposed problem, we use particle swarm optimisation (PSO) and simulated annealing (SA) methods to solve the model in order to evaluate accuracy and reliability of results. The numerical performance of each method is examined. It is indicated that the SA algorithm demonstrates a reasonable CPU time and acceptable accuracy of the results. Results show the ability of the model to optimise yard crane scheduling in container terminals considering preventive maintenance and the velocity coefficient of yard cranes.