动态调整安全控制参数,让机器人更安全地导航。
Learning to Refine Input Constrained Control Barrier Functions via Uncertainty-Aware Online Parameter Adaptation
- 用神经网络预测不同参数的安全风险,考虑不确定性。
- 通过双重验证筛选有效参数,确保安全与性能平衡。
- 适合需要实时安全保障的机器人控制场景。
控制屏障函数(CBF)已成为保障非线性系统安全的强大工具,但在存在输入约束的系统中,找到能持续保证安全性和可行性的有效CBF仍是一个开放挑战。传统方法通常需预先手动调参,而控制器性能对这些固定参数高度敏感,可能导致过度保守或安全失效。本文提出一种基于学习的最优控制框架,用于离散时间非线性系统中输入约束控制屏障函数(ICCBF)参数的在线自适应。方法采用概率集成神经网络,预测候选参数在性能和风险指标上的表现,同时量化认知不确定性(epistemic)与随机不确定性(aleatoric)。提出两步验证流程:利用Jensen-Renyi散度和分布鲁棒条件风险价值(distributionally-robust CVaR),识别有效参数集。由此实现根据当前状态与邻近环境动态优化ICCBF参数,兼顾性能提升与安全保障。实验表明,在机器人导航任务中,该方法在安全性与性能指标上均优于固定参数及现有自适应方法。
原文摘要 · Abstract (English)
Control Barrier Functions (CBFs) have become powerful tools for ensuring safety in nonlinear systems. However, finding valid CBFs that guarantee persistent safety and feasibility remains an open challenge, especially in systems with input constraints. Traditional approaches often rely on manually tuning the parameters of the class K functions of the CBF conditions a priori. The performance of CBF-based controllers is highly sensitive to these fixed parameters, potentially leading to overly conservative behavior or safety violations. To overcome these issues, this paper introduces a learning-based optimal control framework for online adaptation of Input Constrained CBF (ICCBF) parameters in discrete-time nonlinear systems. Our method employs a probabilistic ensemble neural network to predict the performance and risk metrics, as defined in this work, for candidate parameters, accounting for both epistemic and aleatoric uncertainties. We propose a two-step verification process using Jensen-Renyi Divergence and distributionally-robust Conditional Value at Risk to identify valid parameters. This enables dynamic refinement of ICCBF parameters based on current state and nearby environments, optimizing performance while ensuring safety within the verified parameter set. Experimental results demonstrate that our method outperforms both fixed-parameter and existing adaptive methods in robot navigation scenarios across safety and performance metrics.
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