Learning Flexible Job Shop Scheduling under Limited Buffers and Material Kitting Constraints
This addresses a practical scheduling problem in manufacturing with incremental improvements for production efficiency.
The paper tackles the Flexible Job Shop Scheduling Problem with limited buffers and material kitting constraints, which are often ignored in prior studies, by proposing a deep reinforcement learning method with a heterogeneous graph network; experimental results show it outperforms traditional heuristics and advanced DRL methods in makespan and pallet changes on synthetic and real datasets.
The Flexible Job Shop Scheduling Problem (FJSP) originates from real production lines, while some practical constraints are often ignored or idealized in current FJSP studies, among which the limited buffer problem has a particular impact on production efficiency. To this end, we study an extended problem that is closer to practical scenarios--the Flexible Job Shop Scheduling Problem with Limited Buffers and Material Kitting. In recent years, deep reinforcement learning (DRL) has demonstrated considerable potential in scheduling tasks. However, its capacity for state modeling remains limited when handling complex dependencies and long-term constraints. To address this, we leverage a heterogeneous graph network within the DRL framework to model the global state. By constructing efficient message passing among machines, operations, and buffers, the network focuses on avoiding decisions that may cause frequent pallet changes during long-sequence scheduling, thereby helping improve buffer utilization and overall decision quality. Experimental results on both synthetic and real production line datasets show that the proposed method outperforms traditional heuristics and advanced DRL methods in terms of makespan and pallet changes, and also achieves a good balance between solution quality and computational cost. Furthermore, a supplementary video is provided to showcase a simulation system that effectively visualizes the progression of the production line.