A development methodology for cyber-physical systems based on deterministic Theatre with hybrid actors

The goal of the work described in this paper is to propose a development approach for cyber-physical systems (CPS) which relies on actors as the fundamental modelling blocks. The approach is characterized by its capability to deal with the discrete aspects of the cyber part of a CPS, as well as the continuous behaviour of the physical part. More in particular, the approach is based on the Theatre actor system which fosters determinism in model behaviour, and favours model continuity when switching from system modelling and analysis down to prototype and synthesis phases. A key factor of Theatre is the possibility to combine both discrete-event actors, which operate on a discrete timeline, with continuous-time actors which reproduce, in general by using Ordinary Differential Equations (ODEs), the dynamical evolution of physical components. For formal property assessment, Theatre actors (both discrete and continuous) can be reduced to Timed Automata (TA) in the context of the Uppaal toolbox, where the exhaustive and/or the statistical model checkers can be exploited. This paper first describes the proposed approach, then it demonstrates its suitability to CPS modelling and analysis through examples. The paper also discusses how abstract and formal modelling actor concepts can be naturally transitioned to implementation concepts in Java.