Enforcing Safety at Runtime for Systems with Disturbances
Enforcing Safety at Runtime for Systems with Disturbances
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DOI：
10.1109/cdc42340.2020.9304203
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发表时间：
2020-08
期刊：
影响因子：
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通讯作者：
Matthew Abate;S. Coogan
中科院分区：
文献类型：
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作者：
Matthew Abate;S. Coogan
有保证的控制器是通过在运行时过滤所需的控制输入来强制在线安全的控制器，并且控制屏障函数（CBF）提供了有保证的控制器，该控制器呈现状态空间前向不变式的安全子集。在这项工作中，我们提出了一种针对具有扰动的系统的基于 CBF 的运行时保证的问题表述，并且解决该问题的控制器必须以某种方式结合可达集的在线计算。一般来说，在存在干扰的情况下计算可达集的计算成本很高，并且不能直接合并到 CBF 框架中。为此，我们提出了该问题的特殊解决方案，即通过混合单调性属性来近似可达集。存在用于过度近似具有超矩形的混合单调系统的可达集的有效算法，并且我们证明这种近似适合合并到基于 CBF 的运行时保证框架中。
An assured controller is one that enforces safety online by filtering a desired control input at runtime, and control barrier functions (CBFs) provide an assured controller that renders a safe subset of the statespace forward invariant. In this work, we present a problem formulation for CBF-based runtime assurance for systems with disturbances, and controllers that solve this problem must, in some way, incorporate the online computation of reachable sets. In general, computing reachable sets in the presence of disturbances is computationally costly and cannot be directly incorporated in a CBF framework. To that end, we present a particular solution to the problem, whereby reachable sets are approximated via the mixed-monotonicity property. Efficient algorithms exist for over-approximating reachable sets for mixed-monotone systems with hyperrectangles, and we show that such approximations are suitable for incorporating into a CBF-based runtime assurance framework.