Runtime Monitoring for Cyber-physical Systems: A Case Study of Cooperative Adaptive Cruise Control

Cyber-Physical Systems (CPS) involve deep interactions between computation cores, communication networks, and physical environments. These systems are inherently complex and highly nondeterministic. This makes the traditional formal verification technology impractical to verify the complete system behavior, and testing alone is insufficient to guarantee correctness. Runtime monitoring, known as a lightweight verification technique, provides a practical way to monitor and verify such systems at runtime. In this paper, we present a case study for runtime monitoring of the Cooperative Adaptive Cruise Control systems (CACC) in automobile CPS systems. We build a hybrid automaton-based model for the CACC system using the CHARON modeling language and construct an event-based runtime monitoring framework. The synthesized monitor observes the running of CACC and checks whether it works correctly against the temporal logic safety specification. Experimental results obtained through this case study provide evidence for the efficacy of runtime monitoring of CPS systems.