Flexible job shop scheduling problem with interval grey processing time

Job processing time is not always given accurately as a time quota in a production system, particularly in the complex products manufacturing process. It is meaningful to study novel model and algorithm based on uncertainty processing time so as to solve uncertainty job shop scheduling problems. This paper defines inaccurate time quota as interval grey processing time and subsequently proposes a novel uncertainty job shop scheduling model with the objective of minimizing the interval grey makespan. By defining the arithmetic operations and Gantt chart of interval grey processing time, the elitism genetic algorithm coupling elitism strategy in external memory is designed. Finally, the proposed algorithm is tested with different size cases of composite components job-shop scheduling. Results show the proposed algorithm is suitable for solving the uncertainty job shop scheduling problem with interval grey processing time.