Abstract: To guarantee on-time delivery of the hybrid flow-shop system and reduce energy consumption at the meantime, a modified differential evolution algorithm is proposed for the multi-objective hybrid flow-shop scheduling problem with fuzzy processing time and due date, considering in-stage unrelated parallel machines and sequence-dependent setup time. First, a bi-objective mathematical model is established to minimize on-time delivery penalty and energy consumption. Then, a modified algorithm is developed which efficiently generates high-quality initial solutions with NEH (Nanaz, Enscore, Ham)-based heuristic method, thoroughly exploits neighborhoods with the elite individual challenging mechanism. The modified algorithm highly improves the exploration ability with chaotic search strategy. Finally, the results of the comparison with existing typical algorithms and numerical experiment demonstrate that the proposed algorithm is feasible and effective.

Key words: hybrid flow-shop scheduling; differential evolution algorithm; fuzzy; unrelated parallel machine; setup time