A Model-Assisted Federated Reinforcement Learning Method for Multi-UAV Path Planning
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摘要: 针对多无人机在环境监测传感器网络、灾害应急通信节点等设备位置部分未知场景下的数据收集需求,该文提出一种模型辅助的联邦强化学习多无人机路径规划方法。在联邦学习框架下,通过结合最大熵强化学习与单调价值函数分解机制,引入动态熵温度参数和注意力机制,优化了多无人机协作的探索效率与策略稳定性。此外,设计了一种基于信道建模与位置估计的混合模拟环境构建方法,利用改进的粒子群算法快速估计未知设备位置,显著降低了真实环境交互成本。仿真结果表明,所提算法能够实现高效数据收集,相较于传统多智能体强化学习方法,数据收集率提升4.4%,路径长度减少8.4%,验证了所提算法的有效性和优越性。Abstract:
Objective The rapid advancement of low-altitude Internet of Things (IoT) applications has increased the demand for efficient sensor data acquisition. Unmanned Aerial Vehicles (UAVs) have emerged as a viable solution due to their high mobility and deployment flexibility. However, existing multi-UAV path planning algorithms show limited adaptability and coordination efficiency in dynamic and complex environments. To overcome these limitations, this study develops a model-assisted approach that constructs a hybrid simulated environment by integrating channel modeling with position estimation. This strategy reduces the interaction cost between UAVs and the real world. Building on this, a federated reinforcement learning-based algorithm is proposed, which incorporates a maximum entropy strategy, monotonic value function decomposition, and a federated learning framework. The method is designed to optimize two objectives: maximizing the data collection rate and minimizing the flight path length. The proposed algorithm provides a scalable and efficient solution for cooperative multi-UAV path planning under dynamic and uncertain conditions. Methods This study formulates the multi-UAV path planning problem as a multi-objective optimization task and models it using a Decentralized Partially Observable Markov Decision Process (Dec-POMDP) to address dynamic environments with partially unknown device positions. To improve credit assignment and exploration efficiency, enhanced reinforcement learning algorithms are developed. The exploration capacity of individual agents is increased using a maximum entropy strategy, and a dynamic entropy regularization mechanism is incorporated to avoid premature convergence. To ensure global optimality of the cooperative strategy, the method integrates monotonic value function decomposition based on the QMIX algorithm. A multi-dimensional reward function is designed to guide UAVs in balancing competing objectives, including data collection, path length, and device exploration. To reduce interaction costs in real environments, a model-assisted training framework is established. This framework combines known information with neural networks to learn channel characteristics and applies an improved particle swarm algorithm to estimate unknown device locations. To enhance generalization, federated learning is employed to aggregate local experiences from multiple UAVs into a global model through periodic updates. In addition, an attention mechanism is introduced to optimize inter-agent information aggregation, improving the accuracy of collaborative decision-making. Results and Discussions Simulation results demonstrate that the proposed algorithm converges more rapidly and with reduced volatility (red curves in Fig. 3 andFig. 4 ), due to a 70% reduction in interactions with the real environment achieved by the model-assisted framework. The federated learning mechanism further enhances policy generalization through global model aggregation. Under test conditions with an initial energy of 50–80 J, the data collection rate increases by 1.99–4.94%, and the flight path length decreases by 7.4–16.8% relative to the baseline model (Fig. 6 andFig. 7 ), confirming the effectiveness of the reward function and exploration strategy (Fig. 5 ). The attention mechanism allows UAVs to identify dependencies among sensing targets and cooperative agents, improving coordination. As shown inFig. 2 , the UAVs dynamically partition the environment to cover undiscovered devices, reducing path overlap and significantly improving collaborative efficiency.Conclusions This study proposes a model-assisted multi-UAV path planning method that integrates maximum entropy reinforcement learning, the QMIX algorithm, and federated learning to address the multi-objective data collection problem in complex environments. By incorporating modeling, dynamic entropy adjustment, and an attention mechanism within the Dec-POMDP framework, the approach effectively balances exploration and exploitation while resolving collaborative credit assignment in partially observable settings. The use of federated learning for distributed training and model sharing reduces communication overhead and enhances system scalability. Simulation results demonstrate that the proposed algorithm achieves superior performance in data collection efficiency, path optimization, and training stability compared with conventional methods. Future work will focus on coordination of heterogeneous UAV clusters and robustness under uncertain communication conditions to further support efficient data collection for low-altitude IoT applications. -
Key words:
- UAV /
- Path planning /
- Reinforcement learning /
- Federated Learning (FL) /
- Model-assisted
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1 模型辅助的联邦最大熵强化学习算法
(1) 初始化M架无人机集合,重放缓冲区$ {\mathcal{D}}^{m} $,QMIX参数θ,本地QMIX参数θm=0,目标网络参数$ {\widehat{\theta }}^{m}={\theta }^{m} $,目标网络更新周期Ntarget,
聚合周期Nfreq(2) for e=0,1,···, Emax-1 do (3) (a)现实世界数据收集 (4) for 每个无人机m∈M do (5) t=0,初始化状态s0 (6) while $ {E}_{t}^{m}\ge 0 $ do (7) 采样动作$ {\mathit{a}}_{t}^{m}~{\pi }_{\theta }\left({\mathit{a}}_{t}^{m}\right|{s}_{t}^{m}) $ (8) 使用批评网络计算Q值$ Q({s}_{t}^{m},{\mathit{a}}_{t}^{m}) $ (9) 根据安全控制器执行$ {\mathit{a}}_{t}^{m} $,观察新状态$ {s}_{t+1}^{m} $和奖励$ {r}_{t}^{m} $ (10) 将$ \left({{s}_{t}^{m},\mathit{a}}_{t}^{m},{r}_{t}^{m},{s}_{t+1}^{m}\right) $存储在$ {\mathcal{D}}^{m} $中 (11) t=t+1 (12) end while (13) end for (14) (b)学习信道模型并估计未知设备位置,建立模拟环境 (15) (c)模拟环境训练 (16) for episode=0,1,···,N-1 do (17) for 每个并行的无人机m∈M do (18) t=0,初始化状态s0 (19) while $ {E}_{t}^{m}\ge 0,\forall j=\mathrm{1,2},\cdots ,M $ do (20) for 每个模拟代理$ j=\mathrm{1,2},\cdots ,M $ do (21) $ {\tau }_{t}^{j}={\tau }_{t-1}^{j}\cup \{{o}_{t}^{j},{\mathit{a}}_{t-1}^{j}\} $ (22) 使用SAC策略选择动作$ {\mathit{a}}_{t}^{j}~{\pi }_{\theta }\left({\mathit{a}}_{t}^{j}\right|{s}_{t}^{j}) $ (23) 使用评价网络计算Q值$ Q({s}_{t}^{j},{\mathit{a}}_{t}^{j}) $,并更新策略 (24) end for (25) 采取联合动作$ {\times }_{j}{\mathit{a}}_{t}^{j} $,观察$ {\times }_{j}{o}_{t+1}^{j} $,获得奖励rt和下一个状态st+1 (26) 将$ \left({s}_{t},{\times }_{j}{o}_{t}^{j},{\times }_{j}{\mathit{a}}_{t}^{j},{r}_{t},{s}_{t+1},{{\times }_{j}o}_{t+1}^{j}\right) $存储在$ {\mathcal{D}}^{m} $中 (27) t=t+1 (28) end while (29) end for (30) 从$ {\mathcal{D}}^{m} $中随机采样一批B片段,计算Qtot,并使用目标网络$ {\widehat{\theta }}^{m} $计算目标Qtot (31) 更新评价网络参数,最大化期望奖励并正则化熵 (32) $ {\theta }^{m}\leftarrow {\theta }^{m}-\alpha \nabla \mathcal{L}\left({\theta }^{m}\right) $ (33) if mod (episode,Ntarget)=0 then (34) 重置$ {\widehat{\theta }}^{m}={\theta }^{m} $ (35) end if (36) end for (37) if mod (episode,Nfreq)=0 then (38) 更新$ \theta =\sum _{m=1}^{M}{w}_{m}{\theta }_{m} $并设置$ {\theta }^{m}\leftarrow \theta ,\forall m\in M $ (39) end if (40)end for 表 1 训练超参数
训练参数 数值 折扣因子γ 0.99 软更新率τ 0.005 经验池大小$ \mathcal{D} $ 5000 批量样本数B 32 网络学习率lr 0.0003 演员网络学习率lactor 0.0003 温度参数学习率lα 0.0002 目标熵值 0.3 注意力头数n 4 优化器 Adam -
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