An evolutionary algorithm for a hybrid flowshop scheduling problem with consistent sublots. (23rd November 2021) - Zhang, Xinli
Lot streaming is the most often used technique to support the time-based strategy in the modern manufacturing system, which can split the jobs (or lots) with larger size into several sublots with smaller size. With this manufacturing technique, this paper studies a hybrid flowshop scheduling problem with consistent sublots (HFSP_CS). With the consideration of the integrated optimisation of lot sequencing and lot splitting, a mixed-integer linear programming (MILP) model is established with the objective of minimising the total flowtime. Since the NP-hard property of the problem, a solution method integrating the migrating birds optimisation (MBO) and variable neighbourhood descent (VND) algorithms is developed. Moreover, by taking into account the problem-special characteristics, the two-layer coding mechanism and a corresponding initialisation method are designed. Some heuristic methods are also presented in the decoding process. In the computational study, the effectiveness of the proposed algorithm is evaluated by comparing with CPLEX solver and other state-of-the-art algorithms.