Synthesis of resilient fallback control system under cyber-attacks via supervisory control

• Published in: Advanced robotics Vol. 38; no. 9-10; pp. 659 - 671
• Main Authors: Sakata, Kousei, Sawada, Kenji, Ogura, Takashi, Fujita, Junya, Matsumoto, Noritaka
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 18.05.2024
• Subjects: control system security; discrete event system; fallback control system; Industrial control system; supervisory control
• ISSN: 0169-1864; 1568-5535
• DOI: 10.1080/01691864.2024.2329947

Industrial control systems (ICS) require system design and operation under cyber-attacks. This study aims to design a fallback control system that can switch from normal control to fallback control and verify its superiority. The target system is a factory automation (FA) system consisting of a normal programmable logic controller (PLC) and a fallback PLC. In this system, we design a fallback logic that takes over control in the case of cyber-attacks. The design of this logic requires a system model that manages smooth state transitions between normal control and fallback control in an integrated manner under cyber-attacks. In response, we model a control program in the framework of discrete event systems (DESs) and apply supervisory control to derive a supervisor model that can manage the system in an integrated manner. To ensure the controllability of the FA system during cyber-attacks, we design a control specification that includes a detection function to enable rapid switching of the control state. As a result, we generate the fallback logic from the supervisor model with guaranteed controllability under cyber-attacks and implement it in a fallback PLC to verify the effectiveness of the proposed logic.