Optimization of Steel Plate Yard Outbound Operation Toward Multiple Cutting Lines

As the most important session of the intelligent yard, this paper considers the optimization of steel plate yard outbound operation that orients to multiple cutting lines. According to the cutting requirements, the yard should retrieve cutting plates distributed in different places, during which outbound orders of cutting plates and relocation strategy of blocking plates should be considered. Since outbound and cutting operations are performed simultaneously, cutting influence should be considered when formulating outbound operations. Therefore, instead of improving the outbound efficiency only, this problem aims to reduce the makespan of the entire process. We introduce a hybrid BVNS-RSP algorithm to solve this problem. The algorithm uses basic variable neighborhood search to decide outbound order and implements a relocation sub-problem model to determine the relocation strategy. Two initial heuristics are developed to fasten the search efficiency. Experimenting with actual data demonstrates the performance of the algorithm. Besides, results under different cut time variations illustrate their effect on makespan, thus providing suggestions for cutting plan formulation. Note to Practitioners—This paper considers a practical problem in shipbuilding’s steel plate yard. Currently, the outbound operation of steel plate yards mainly relies on manual experience, which is inefficient. With upgrading technologies such as wireless sensors and the Internet of Things, it is possible to establish an intelligent yard. So that, given the cutting plan, the required plates can be retrieved and sent to cutting lines automatically without human intervention. The efficiency of outbound operation is vital to the whole process, and the operational planning session that translates complex cutting plans into executable operation instructions is the most crucial part of this system. This work fills in this section and improves the outbound efficiency by optimizing the crane’s trajectory and eliminating redundant moves. Besides, this paper also provides some constructive suggestions for cutting plan development, helping the shipbuilding technical center to formulate cutting plans more scientifically.