Flow shop scheduling with variable processing times based on differential shuffled frog leaping algorithm

In the problem of flexible flow shop scheduling with variable processing times, the change of processing speed often affects product quality and causes fluctuations in capacity, which makes it difficult to solve the scheduling problem. In the light of the flexible flow-shop scheduling problem with variable processing times (FFSP-VPT), the FFSP-VPT mathematical model is established. The improved differential shuffled frog leaping algorithm (DSFLA) serves as the global optimisation algorithm. It overcomes the shortcomings of the adaptive shuffled frog leaping algorithm which easily falls into local optimum and converges slowly. The two-stage coding method is used to determine the online sequence of the job and processing speed of the stage with variable processing times. The simulation experiments confirm the improvement of the shuffled frog leaping algorithm in global search ability and its effectiveness in solving the flexible flow shop scheduling problem with variable processing times.