Behaviors Modeling and Analysis for Cyber-Physical Systems

Cyber-physical systems (CPS) are complex systems, which integrate computational and physical components with the control loops. And an early modeling and quantitative analysis of CPS behaviors can reduce development difficulties and improve system reliability. However, CPS behaviors, especially the behaviors of the control loops and time behaviors, lack a systematic description and quantitative analysis. For this end, this paper proposes an approach called OODA-CPS, which integrates the modeling processes of visual modeling, formal modeling and quantitative analysis of CPS behaviors. The OODA-CPS approach is created based on the OODA (observe, orient, decide, act) system architecture, and incorporates the SysML model and the Network of Priced Timed Automata (i.e., NPTA) model. Concretely, OODA-CPS: 1) presents an explicit description on CPS behaviors by extending the SysML sequence diagram, 2) provides an automatic transformation from the CPS visual model (i.e., the extended SysML sequence diagram) to the CPS formal model (i.e., the NPTA model), and 3) provides a quantitative analysis on the OODA control loop behaviors and the time behaviors of CPS. To evaluate the approach, we present an example application, and the results demonstrate that the approach can effectively reduce modeling and analysis difficulties of the CPS behaviors.