研究了一种单机环境下集成生产和维护的双目标优化调度问题。机床的故障间隔时间和平均维修时间服从指数分布,同时结合加工序列相关准备时间。预防性维护活动不能与作业加工同时进行,但与准备时间不相冲突。调度目标是同时最小化作业总计完成时间和机床不可得性。在问题建模的基础上,构造了一种基于Lorenz非劣关系的分类遗传算法(表示为L-NSGA-Ⅱ),详细设计了算法的核心部分。最后,通过大量计算实验,将L-NSGA-II算法与NSGA-II算法进行了比较分析,说明了L-NSGA-II算法的有效性。
A multi-objective optimization problem for integrated production scheduling and preventive maintenance planning in a single machine environment is investigated in this paper.The time to failure(repair)of the machine is subject to an exponential distribution.The sequence-dependent setup times are also considered into the problem,which can be processed with preventive maintenance activities simultaneously.The job processing is non-preemptive with preventive maintenance activity.The objectives are to minimize the total completion times of jobs and to minimize the unavailability of the machine at the same time.The integrated optimization problem is established.To solve this problem,a method combined with Lorenz dominance relationship and Non-dominated Sorting Genetic Algorithm(NSGA-II)is adapted(denoted as L-NSGA-II),in which the key elements are designed.The computational experiments for different scenario are conducted,and the results with comparisons show the effectiveness of the proposed L-NSGA-II.