Smart Commander: A Hierarchical Reinforcement Learning Framework for Fleet-Level PHM Decision Optimization
Authors: Yong Si, Mingfei Lu, Jing Li, Yang Hu, Guijiang Li, Yueheng Song, Zhaokui Wang
Organizations: School of Aerospace Engineering, Tsinghua University, China · College of Information and Control Engineering, Xi’an University of Architecture and Technology, China · Hangzhou International Innovation Institute, Beihang University, China · First Aircraft Institute of Aviation Industry Corporation of China, China · Science and Technology on Complex Aviation System Simulation Laboratory, China
Decision-making in military aviation Prognostics and Health Management (PHM) faces significant challenges due to the "curse of dimensionality" in large-scale fleet operations, combined with sparse feedback and stochastic mission profiles. To address these issues, this paper proposes Smart Commander, a novel Hierarchical Reinforcement Learning (HRL) framework designed to optimize sequential maintenance and logistics decisions. The framework decomposes the complex control problem into a two-tier hierarchy: a strategic General Commander manages fleet-level availability and cost objectives, while tactical Operation Commanders execute specific actions for sortie generation, maintenance scheduling, and resource allocation. The proposed approach is validated within a custom-built, high-fidelity discrete-event simulation environment that captures the dynamics of aircraft configuration and support logistics.By integrating layered reward shaping with planning-enhanced neural networks, the method effectively addresses the difficulty of sparse and delayed rewards. Empirical evaluations demonstrate that Smart Commander significantly outperforms conventional monolithic Deep Reinforcement Learning (DRL) and rule-based baselines. Notably, it achieves a substantial reduction in training time while demonstrating superior scalability and robustness in failure-prone environments. These results highlight the potential of HRL as a reliable paradigm for next-generation intelligent fleet management.
Figures & tables
Figure 1. Hierarchical decision-making architecture of the Smart Commander framework. The General Commander operates at the strategic level, coordinating global fleet objectives, while Operation Commanders function at the tactical level, managing specific subsystems (flight operations, maintenance, and resources).
Figure 2. Training dynamics under nominal conditions. The Smart Commander (HRL, purple) converges faster than DRL (orange) across all metrics. Top row: availability rate ( rab ) and cost-benefit ratio ( rcb ). Middle row: mission success rate ( rms ) and sortie success rate ( rss ). Bottom row: total cost ( Ctotal ) and virtual cost-benefit ratio ( rvcb ).
Figure 3. Training rewards under nominal conditions. Top: General Commander reward ( RG ). Bottom: Operation Commanders’ rewards ( RF , RM , RR ). The HRL framework achieves quicker convergence and higher rewards compared to DRL.
Metric
Rule-Based
DRL
HRL (Ours)
rab (%)
92.3±2.1
94.5±1.8
96.2±0.9
rms (%)
81.6±3.5
87.3±2.2
92.1±1.3
rss (%)
86.9±2.8
90.7±1.9
93.5±1.1
ttc (k)
1150±210
1890±723
1230±109
rcb
2.3±0.03
1.22±0.02
0.75±0.02
rvcb
–
4.35±0.25
0.05±0.01
Table 1. Performance comparison under nominal conditions. Values are mean ± std over 5 random seeds. Best results in bold .
Figure 4. Scalability analysis under varying system complexity ( λ ). The Smart Commander (HRL, purple) maintains high performance as complexity increases, while DRL (orange) and Rule-Based (green) methods degrade significantly.
Figure 5. Robustness analysis under varying failure intensities ( ε ). The Smart Commander (HRL, purple) maintains stable performance across all failure rates, while DRL (orange) and Rule-Based (green) methods degrade significantly in harsh environments ( ε<1.0 ). Layout same as Figure 4 .
Appendix figures & tables9 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 6. Simulation model architecture with mission, fleet-health, and support/logistics modules.
Figure 7. Simulation flow of fleet operations in each DES cycle.
Hierarchical reinforcement learning studies policies that organize decisions into reusable skills, subgoals, or actions operating at different timescales.
National Elite Institute of Engineering,Northwestern Polytechnical University, Xi’an, Shanxi, China · School of Automation, Northwestern Polytechnical University, Xi’an, Shanxi, China
Polytechnic Institute, Zhejiang University, 310015, Hangzhou, China · S.F. Technology Co., Ltd., 518054, Shenzhen, China · School of Management, Zhejiang University, 310058, Hangzhou, China