Multi-objective flow shop group scheduling with separable setup time and handling time

To solve group scheduling problem for flow shop in which setup time and handling time could be separated, a multi-objective decision model with the ideal point method which took the makespan as main optimization goal, and the shutdown frequency and the handling times of group jobs as subordinate optimization goals was established. Aiming at the problems of solving makespan and developing operational planning for group jobs, three types of time models were constructed. A new genetic algorithm of setup time and handling time separable was designed for group jobs scheduling. The effectiveness of proposed algorithm was verified through two small size simulation experiments. To further assess the performance of the algorithm for a large size problem, it was compared with the simple genetic algorithm, and the results showed that the researches could determine the optimal scheduling scheme of group jobs as well as make precise planning for the processes of processing and handling. The new designed genetic algorithm could get the ideal solution within an acceptable computation time.