Abstract: Two-stage flexible flow shop scheduling problem with task tail group constraint and releasing in batch is proposed, where the two stages are made up of unrelated machines. Based on defining two-stage flexible flow shop with tail group constraint and giving its mathematical description systematically, the optimization model of the two-stage flexible flow shop scheduling is put forward. Through analyzing of this kind of problem, a rule of advantage scheduling (theorem 1) is proved. According to theorem 1, a new heuristic method based on combinatorial dispatching rule, is designed. In order to validate the method and compare and evaluate the new heuristic, a simulation method is presented, and then twelve dispatching rules based on the literatures and heuristic are adopted in the scheduling simulation. Simulation results indicate that the heuristic method is effective and heuristic outperforms the other twelve dispatching rules with respect to the two-stage flexible flow shop scheduling problem proposed.

Key words: Flexible flow shop, Heuristic, Tail group constraint