Journal of System Simulation ›› 2024, Vol. 36 ›› Issue (7): 1609-1620.doi: 10.16182/j.issn1004731x.joss.23-0385

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Real-time Scheduling Method for Dynamic Flexible Job Shop Scheduling

Jiang Quan(), Wei Jingxuan()   

  1. School of Computer Science and Technology, Xidian University, Xi'an 710065, China
  • Received:2023-04-06 Revised:2023-05-29 Online:2024-07-15 Published:2024-07-12
  • Contact: Wei Jingxuan E-mail:jq18890952@163.com;wjx@xidian.edu.cn

Abstract:

A multi-objective dynamic flexible job shop scheduling problem model with machine breakdown and random jobs arrival is constructed to address the interference of dynamic events in manufacturing processing on the scheduling scheme, and a real-time scheduling method with multi-objective proximal policy optimization (MPPO) algorithm is proposed. The MPPO algorithm trains two agents, routing agent (RA) and sequencing agent (SA), for real-time scheduling and real-time processing of dynamic events. It employs a linear combination of weight vectors and reward vectors as reward signals and stores the agents' parameters for each weight vector to optimize multiple objectives. The required state information, scheduling rules, and reward signals are defined for the two agents in conjunction with the objective functions. A comparison with nine combinations of scheduling rules for dynamic scheduling problems of different scales verifies that the MPPO algorithm-trained agents have learned an appropriate scheduling policy, which can guarantee the performance of real-time scheduling and optimize all objectives.

Key words: dynamic scheduling, flexible job shop scheduling, reinforcement learning, multi-agent, multi-objective optimization

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