外观
论文arXiv 2610.2025513 天前
后退视界安全评论器与可微动作盾提升四足RL鲁棒性
本文由 AI 根据公开内容整理,可能有误,请以原文为准:Safe Reinforcement Learning with Receding-Horizon Safety Critic and Differentiable Action Shields(arXiv 2610.20255)
核心内容
针对机器人强化学习中安全故障非瞬时发生、常在多步后由扰动或域偏移引发的痛点,研究提出一种基于后退视界的安全评论器(Receding-Horizon Safety Critic)。该机制不依赖马尔可夫假设,而是预测状态在未来时间窗内是否保持非终止,实现对运动失效的 anticipatory 检测。在四足机器人仿真测试中,该方法有效提升了系统在动作噪声、外部扰动及地形变化下的鲁棒性,在维持竞争性回报的同时减少了灾难性故障。
技术上,评论器采用复合目标训练,融合视界分类、受控制障碍函数(CBF)启发的时序一致性及平滑正则化,并通过集成学习与条件风险价值(CVaR)估计处理不确定性。基于此构建闭式可微CBF安全滤波器,以最小代价修正策略动作;同时将其集成至PPO算法并引入预期损失(Anticipation Loss),缓解训练中策略与滤波器的失配问题,实现了端到端的安全强化学习优化。
关键看点
- 后退视界预测:突破马尔可夫假设限制,通过学习评论器预测未来窗口状态安全性,提前识别由扰动和域偏移导致的潜在运动失效。
- 复合训练目标:结合视界分类、CBF时序一致性约束及平滑正则化训练评论器,并利用CVaR聚合集成模型以量化预测不确定性。
- 可微安全滤波:推导闭式可微CBF滤波器最小化动作修正量,集成至PPO并引入预期损失,解决训练阶段策略与安全层的失配难题。
- 四足仿真验证:在模拟环境中验证了方法对动作噪声、外部冲击及地形突变的适应性,证实能在保障任务回报前提下降低灾难性失败率。
工程与产业观察
该工作为具身智能体在开放动态环境中的安全部署提供了新范式。通过将前瞻式安全评估与可微控制层深度融合,解决了传统RL安全约束滞后及不可导难题。对于四足等腿足机器人开发者,该架构证明了在不牺牲性能前提下实现主动安全防御的可行性,对Sim-to-Real迁移中的鲁棒性增强具有重要工程参考价值。
英文摘要 (Abstract)
Despite the Markov assumption, safety failures in robot reinforcement learning rarely occur instantaneously; they typically emerge over several steps as the policy enters unfamiliar states under disturbances and domain shift. We address this limitation by learning a receding-horizon safety critic that predicts whether a state will remain non-terminating over the next receding horizon, enabling anticipatory detection of impending locomotion failures. The critic is trained from rollout-derived horizon labels with a composite objective that combines horizon classification, control-barrier-function-inspired temporal consistency, and smoothness regularization, and we aggregate an ensemble of critics with a conservative Conditional Value at Risk estimate to account for uncertainty. Building on the learned critic, we derive a closed-form, differentiable CBF-style safety filter that minimally modifies the policy action to improve predicted safety, and integrate it into PPO with an anticipation loss to reduce policy-filter mismatch during training. In simulated quadruped locomotion, our method improves robustness under action noise, external perturbations, and terrain shifts, reducing catastrophic failures while maintaining competitive returns.
作者:Siwei Ju, Jan Peters, Oleg Arenz
来源
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