ExCHARON: Improved Modeling Language for Cyber-Physical Systems based on CHARON

Abstract

Cyber-physical systems (CPSs) are integrations between computation and physical processes. Embedded computers and networks monitor and control the physical processes, usually with feedback loops in which the physical processes affect the computations and vice versa. In the physical world, the passage of time is inexorable and concurrency intrinsic. Moreover, as CPSs include discrete as well as continuous behavior, they are difficult to model in discrete modeling languages, such as UML, SMV, SPIN and STATECHART. Hence, CPSs need be modeled and verified with hybrid system modeling languages. In order to model CPSs precisely, we revised and extended the hybrid system modeling language CHARON to a language called ExCHARON. In addition to the features that CHARON supports ExCHARON newly supports defining a graphical syntax of modes and variables, adding qualified names, changing the communications methodology, separating mixtures of communication and interlevel connections, and adding urgent transitions and signal variables. These new features of ExCHARON enhance simplicity as well as the readability and expressiveness of CPS models.