Minimizing makespan at module assembly shop in shipbuilding

With the wide application of module shipbuilding mode, module spatial scheduling problems occur in various working areas and constrain the productivity of shipbuilding. It is a NP-hard problem to obtain optimum scheduling due to the complex constraints. On the basis of investigation on the characteristics of module shape and processing technique, a heuristic module spatial scheduling algorithm meeting due dates, maximizing utilization of work plates and minimizing makespan is developed with the consideration of spatial and time constraints. Also, a target of spatiotemporal utilization ratio is proposed and used in improving the algorithm. With the algorithm, visual results of daily layouts and work orders can be easily obtained. The operation results using real shipyard data show that the module spatial scheduling performance and efficiency are satisfactory.