Safety Filters for Black-Box Dynamical Systems by Learning Discriminating Hyperplanes

Fuente: arXiv
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Auteurs principaux: Lavanakul, Will, Choi, Jason J., Sreenath, Koushil, Tomlin, Claire J.
Format: Preprint
Publié: 2024
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author Lavanakul, Will
Choi, Jason J.
Sreenath, Koushil
Tomlin, Claire J.
author_facet Lavanakul, Will
Choi, Jason J.
Sreenath, Koushil
Tomlin, Claire J.
contents Learning-based approaches are emerging as an effective approach for safety filters for black-box dynamical systems. Existing methods have relied on certificate functions like Control Barrier Functions (CBFs) and Hamilton-Jacobi (HJ) reachability value functions. The primary motivation for our work is the recognition that ultimately, enforcing the safety constraint as a control input constraint at each state is what matters. By focusing on this constraint, we can eliminate dependence on any specific certificate function-based design. To achieve this, we define a discriminating hyperplane that shapes the half-space constraint on control input at each state, serving as a sufficient condition for safety. This concept not only generalizes over traditional safety methods but also simplifies safety filter design by eliminating dependence on specific certificate functions. We present two strategies to learn the discriminating hyperplane: (a) a supervised learning approach, using pre-verified control invariant sets for labeling, and (b) a reinforcement learning (RL) approach, which does not require such labels. The main advantage of our method, unlike conventional safe RL approaches, is the separation of performance and safety. This offers a reusable safety filter for learning new tasks, avoiding the need to retrain from scratch. As such, we believe that the new notion of the discriminating hyperplane offers a more generalizable direction towards designing safety filters, encompassing and extending existing certificate-function-based or safe RL methodologies.
format Preprint
id arxiv_https___arxiv_org_abs_2402_05279
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Safety Filters for Black-Box Dynamical Systems by Learning Discriminating Hyperplanes
Lavanakul, Will
Choi, Jason J.
Sreenath, Koushil
Tomlin, Claire J.
Machine Learning
Learning-based approaches are emerging as an effective approach for safety filters for black-box dynamical systems. Existing methods have relied on certificate functions like Control Barrier Functions (CBFs) and Hamilton-Jacobi (HJ) reachability value functions. The primary motivation for our work is the recognition that ultimately, enforcing the safety constraint as a control input constraint at each state is what matters. By focusing on this constraint, we can eliminate dependence on any specific certificate function-based design. To achieve this, we define a discriminating hyperplane that shapes the half-space constraint on control input at each state, serving as a sufficient condition for safety. This concept not only generalizes over traditional safety methods but also simplifies safety filter design by eliminating dependence on specific certificate functions. We present two strategies to learn the discriminating hyperplane: (a) a supervised learning approach, using pre-verified control invariant sets for labeling, and (b) a reinforcement learning (RL) approach, which does not require such labels. The main advantage of our method, unlike conventional safe RL approaches, is the separation of performance and safety. This offers a reusable safety filter for learning new tasks, avoiding the need to retrain from scratch. As such, we believe that the new notion of the discriminating hyperplane offers a more generalizable direction towards designing safety filters, encompassing and extending existing certificate-function-based or safe RL methodologies.
title Safety Filters for Black-Box Dynamical Systems by Learning Discriminating Hyperplanes
topic Machine Learning
url https://arxiv.org/abs/2402.05279