Research on Flexible Flow Shop Scheduling Problem with Variable Processing Times

In order to solve the flexible flow shop scheduling problem with variable processing times (FFSP- VPT), this paper analyzes the choice of processing stages with variable processing times, the quality inspection of unqualified products, and the occurrence of rework. As such, the FFSP- VPT mathematical model is established, adopting the fine scheduling process, which changes the traditional rough scheduling to guide the workshop production process. In addition, it not only provides the workshop with some adjustable stages, namely, the stages with variable processing times, but also searches for the balance between processing time and rework rate so as to ensure the processing quality while minimizing the maximum completion time. Based on the traditional Shuffled Frog-Leaping Algorithm(SFLA), we introduce the self-adaptive factor into the maximum update distance of SFLA algorithm, proposing a self-adaptive shuffled frog-leaping algorithm as the global optimization algorithm. What's more, through simulation test, the test result of the proposed algorithm is compared with those of other algorithms, which verifies the effectiveness of the SFLA algorithm in solving practical FFSP- VPT problems.