Simulation-based overhead-crane scheduling for a manufacturing plant

The overhead-crane scheduling problem with spatial constraints has attracted extensive attention and lots of approaches are introduced to solve the problem. As we all know, in the manufacturing plant the crane scheduling is one part of the production scheduling. However, most of approaches concern the crane scheduling in isolation. In this paper, we include the crane scheduling problem into the production scheduling environment and combine them together to obtain an integrated schedule. A simulation-based optimization solves this integrated scheduling problem. A genetic algorithm is introduced to determine the allocation of machines and cranes. A simulation model referring to a queuing network is used to evaluate the crane and machine allocation results and provides the fitness value for the genetic algorithm. The sequences of operations (processing and transporting) on each machine and each crane are determined by using the dispatching rule LPT. A heuristic deals with crane collision events.