A two-stage discrete water wave optimization algorithm for the flowshop lot-streaming scheduling problem with intermingling and variable lot sizes

摘要

Considering lot-streaming of different orders in the actual production system, this paper examines the lot-streaming scheduling problem in flowshop production system. Given production sublots of the different jobs allowed to be intermingled in the production process, we take a deeper dive into the flowshop lot-streaming scheduling problem with detached setup and transfer batches for production sublots of jobs. And the mathematical model is presented with the objective of makespan. To tackle the complexity of the problem at hand, a two-stage discrete water wave optimization (TSDWWO) algorithm is proposed to optimize the sublots and sequencing. In the algorithm, a double-wave parallel encoding scheme is designed for two kinds of water waves, which are splitting wave and sequencing wave. Besides, considering the operation effect and time of the algorithm, the corresponding operations during the process of wave propagation are improved for these two kinds of waves respectively. Afterward, the parameters of the proposed TSDWWO are calibrated by the design of experiments approach. To evaluate the performance of the proposed TSDWWO, two different types of test sets are utilized in the experiments, which are the test sets in the literature and test sets randomly generated containing instances of variant scales. Compared with other existing algorithms in the literature, the results show the efficiency of this approach for the flowshop lot-streaming scheduling problem.