A Modular Safety Filter for Safety-Certified Cyber-Physical Systems

TL;DR

This paper presents a modular safety filter for cyber-physical systems that enhances safety during cyber attacks without compromising control performance, applicable to various attack types and compatible with existing controllers.

Contribution

The paper introduces a novel modular safety filter that operates independently of attack detection reliability, ensuring safety in cyber-physical systems during diverse cyber attacks.

Findings

Effective safety maintenance during undetectable attacks

Compatible with high-performance controllers

Validated on multi-agent robot formation task

Abstract

Nowadays, many control systems are networked and embed communication and computation capabilities. Such control architectures are prone to cyber attacks on the cyberinfrastructure. Consequently, there is an impellent need to develop solutions to preserve the plant's safety against potential attacks. To ensure safety, this paper introduces a modular safety filter approach that is effective for various cyber-attack types. This solution can be implemented in combination with existing control and detection algorithms, effectively separating safety from performance. The safety filter does not require information on the received command's reliability or the anomaly detector's feature. It can be implemented in conjunction with high-performance, resilient controllers to achieve both high performance during normal operation and safety during an attack. As an illustrative example, we have shown the effectiveness of the proposed design considering a multi-agent formation task involving 20 mobile robots. The simulation results testify that the safety filter operates effectively during undetectable, intelligent attacks.