基于阻塞流理论的船舶建造中管件加工虚拟单元调度问题研究

Research on Virtual Cell Scheduling of Pipe Processing in Ship Building Based on Theory of Blocking Flow

虚拟单元制造系统是适用于多品种小批量的生产组织模式,其在船舶建造中的应用有利于提高船舶建造的效率和柔性;但如果调度方案不当,容易引起交货期延迟的现象。鉴于船舶建造生产的特点,论文对船舶建造中虚拟单元制造系统的调度问题进行了研究。以某船厂舾装作业中的管件加工为例,在对管系托盘中的管件聚类分析的基础上,采用阻塞流理论,以设备与加工工序的分配和时间为约束,将调度问题转变为最小时间最大流问题。采用改进的预估时间增量算法求解管件族在不同工作地之间加工的最优路径。在生产任务既定的情况下,以完工周期最小化、设备最大负荷最小化、等待时间最小化为优化目标,构建了管件加工多目标优化模型,并采用免疫遗传算法求解。将求解结果与当前企业管件加工实际数据进行对比,并采用Witness软件对存在着多种动态因素的实际生产过程进行仿真,验证了方案的可行性及有效性,该方法对船舶建造中其他生产环节的生产组织亦具有参考和推广意义。

Virtual cells are adapted to the mode of production organization with multi-variety and small batches for improving efficiency and flexibility of ship construction. Existence of inappropriate scheduling schemes will lead to the emergence of delaying in delivery. In this paper pipe processing in ship outfitting in a shipyard is taken as a specific example. Based on the analysis of clustering for salvers in pipe product family and the theory of blocking ^ ow, a multi-objective optimization model of pipe processing in ship construction is constructed, which is bound by time constraint, distribution of equipment and processing operations. When the task of production is given, the scheduling problem is transformed to the max-flow and min-time problem. The model is aimed at the minimizing the completion period, minimizing the maximum of equipment load and minimizing the waiting time. The problem is solved with the immune genetic algorithm. Calculation results are compared with the actual data of pipe processing in the shipyard, while software Witness is applied to the simulation of the production process involving different kinds of dynamic factors. The proposed method would have a good reference for other production procedures in ship construction.