Hybrid robust controller design: Cyber attack attenuation for Cyber-Physical Systems

This paper considers controller design for Cyber-Physical Systems (CPSs) that are robust to various types of cyber attacks. While the previous studies have investigated a secure control by assuming a specific attack strategy, in this paper we propose a hybrid robust control scheme that contains multiple sub-controllers, each matched to a specific type of cyber attacks. Then the system can be adapted to various cyber attacks (including those that are not assumed for sub-controller design) by switching its sub-controllers to achieve the best performance. We propose a method for designing the secure switching logic to counter all possible cyber attacks and mathematically verify the system's performance and stability as well. The performance of the proposed control scheme is demonstrated by an example with the hybrid H
₂
- H
_∞
controller applied to an Unmanned Aerial System (UAS).