柔性作业车间生产计划与调度集成优化求解策略

针对柔性作业车间(Flexible job-shop, FJS)生产计划(Production planning, PP)与调度紧密衔接的特点, 建立了生产计划与调度集成优化模型. 模型综合考虑了安全库存、需求损失及工件加工路线柔性等方面因素. 提出了一种基于拉格朗日松弛(Lagrangian relaxation, LR)的分解算法, 将原问题分解为计划子问题与调度子问题. 针对松弛的生产计划子问题, 提出一种新的费用结构, 以保证生产计划决策与实际情况相符, 并设计了一种变量固定—松弛策略与滚动时域组合算法进行求解. 对于调度子问题中的加工路线柔性问题, 提出了一种新的机器选择策略. 通过数值实验验证了模型与算法的有效性.

Solution Strategy of Integrated Optimization of Production Planning and Scheduling in a Flexible Job-shop

To cope with the interaction between production planning and scheduling in a flexible job shop (FJS), an integrated optimization model for production planning and scheduling is presented. Safety stock, demand loss and flexible process routing of jobs are involved in the model. A decomposition algorithm based on Lagrangian relaxation (LR) is used to solve this model, and the integrated problem is decomposed into a production planning sub-problem and a flexible scheduling sub-problem. For the relaxed production planning sub-problem, a new cost structure is provided in order to make the decision-making coincide with the practical problem, and an algorithm which combines varying fix-and-relax with rolling-horizon is developed to solve the planning sub-problem. For the flexible process routing of the scheduling sub-problem, a new strategy of machine assignment is addressed. Numerical experiments validate the effectiveness of the proposed model and algorithm.