Abstract: In actual workshop processing, six factors should be taken into consideration: (1)submit time of work pieces; (2)adjusting time of machine between different processes and corresponding static expense; (3)processing time of machine and corresponding dynamical expense; (4)raw material cost; (5)due dates which obey time window distribution; (6)alternative machine which is available for specific processes. For this type workshop scheduling, aiming at maximizing minimum customer satisfaction and minimizing sum of raw material, static and dynamic cost, a two-objective fuzzy workshop scheduling model with alternative machines is proposed and the evolutionary algorithm based on improved coding and elite reserved strategy is presented. Meanwhile, the rationality of the algorithm solution is briefly analyzed; and an example is employed to verify the effectiveness of the algorithm, which is providing an approach for fuzzy workshop scheduling of multiple objects and multiple constraints.

Key words: flexible manufacturing system, alternative machines, fuzzy due date, submitted time, setup time, Pareto optimal solution