Abstract: There are many uncertain events in the actual production process of flexible job shop, which affect the normal production and scheduling to achieve objective. According to the factor of the machine breakdown, two robustness measures combined with flexible job shop scheduling characteristics were proposed. One is considered as the initial schedule and the actual schedule makespan deviation, the other one is considered as each machine idle time and work load. The genetic algorithm was used to solve the problem, and the two parts chromosome coding was designed to avoid generating the illegal solution. Through the establishment of the probability function of machine breakdowns, the data of the breakdown machines was generated, which were optimized by the proposed optimization method and the robustness measures. The experimental results show that the proposed method can effectively reduce the process delay and avoid the deterioration of the performance of the actual scheduling.

Key words: flexible job shop scheduling, robust scheduling, machine breakdowns, robustness measurements