考虑批量分割的单元装配系统工作量平衡联合决策模型

Joint decision model of Seru production system balancing considering lot-splitting

针对日本式单元化生产中批量大小不合理导致单元间工作量不平衡的问题,在单元装配系统构建过程中考虑批量分割,构建流水线向单元装配系统转化的多目标优化模型.该模型以最小化总完工时间和最小化工人总工时为目标,对转化过程中单元构建和批量分割进行联合决策.考虑到多目标优化问题特点以及解空间复杂度,增加局部搜索策略,对算法进行改进,提出INSGA-II算法,设计了基于游标的编码方式表示批量分割,满足单元数量动态变化下批量划分约束.在进化过程中不断优化各单元对应产品种类以及批量大小,平衡单元间工作量,缩短总完工时间.最后,通过数值算例验证所提出方法的有效性,结果表明在产品数量波动较大的情况下,考虑批量分割能更好地平衡单元间工作量.

In this paper, lot-splitting is adopted in the process of Seru production system formation for the inter-Seru imbalance problem caused by unreasonable batch size in Seru production. A multi-objective optimization model of line-Seru conversion is developed. Aiming to minimize the total throughput time and the total labor hours, by the model makes joint decisions on Seru formation and lot-splitting in the conversion process. Considering the characteristics of the multi-objective optimization problem and the complexity of the solution space, a local search strategy is added to improved the algorithm, the INSGA-II is proposed to solve the problem, and an encoding method based on vernier is designed to express the lot-splitting strategy to satisfy the constraint when Seru quantity changes. In evolution, the batch sizes and product types of each Seru are continuously optimized to balance the workload between Serus and shorten total throughput time. Finally, the effectiveness of the method is verified by numerical examples. The results show that lot-splitting can better balance the workload between Serus when the quantity of product has high fluctuation.