Abstract: Aiming at optimizing the maximum completion time for Flexible Job Shop Scheduling Problem (FJSP), it proposes an Improved Snake Optimization (ISO) algorithm. This algorithm studies the snake optimization algorithm and uses two-stage coding to replace the real coding of the original algorithm, so that the improved snake optimization algorithm can update the position of the individual snake in the discrete space. In addition, to solve the problem of low initial population quality in the original algorithm, GLR strategy is used to balance the machining load to improve the initialization quality of the algorithm. The position change and interaction mechanism of individual snake in the original algorithm are redesigned by using two operators on the basis of preserving the evolution of the original snake group. Finally, the orthogonal experiment is used to analyze the algorithm parameters, and 15 benchmark examples and 1 case in the workshop are simulated and compared to verify the effectiveness and stability of the proposed algorithm to solve the problem.

Key words: flexible job shop scheduling, discrete optimization problem, improved snake optimization algorithm