Multiple rules decision-based DE solution for the earliness-tardiness case of hybrid flow-shop scheduling problem

The earliness/tardiness (E/T) case of hybrid flow-shop scheduling problem (HFSP) is an NP hard problem, which is difficult to deal with; however, the existence of the multi-rules relating to the practical production increases the complexity of this problem. How to solve the combinatorial optimisation problem effectively and optimally is still an open issue today. In this paper, the joint scheduling strategy of differential evolution (DE) algorithm and factor space-based multiple rules decision method is used to solve this E/T scheduling problem. Firstly, DE algorithm is used to make global assignment and obtain each job's process route. Secondly, factor space method is used to describe the scheduling rules in production process; then a scheduling decision method based on variable weight comprehensive function is considered to figure out the jobs' operating priority in buffer area during the local production assignment between stages; subsequently the starting time of each job can be determined. Finally, under the constraints of the due-date and multiple production rules, the global optimisation with the minimal penalty sum of E/T is obtained. Several scheme comparisons with experiment results show the effectiveness of the proposed method. Copyright © 2012 Inderscience Enterprises Ltd