A New Formalism for Modeling of Reactive and Hybrid Systems
Martin Otter, Martin Malmheden, Hilding Elmqvist, Sven Erik Mattsson, Charlotta Johnsson · Linköping electronic conference proceedings · 2009
A new Modelica library is presented that is used to model safe hierarchical state machines in combination with any Modelica model, e.g., controllers, logical blocks, and physical systems described by differential-algebraic equations.It has been designed to simplify usage, improve safety aspects and to harmonize with the design of the new Modeli-ca_EmbeddedSystems library.Furthermore, new blocks are introduced to define actions in a visual way, and not textually.The library is inspired by Statecharts, Sequential Function Charts, Safe State Machines (SSM) and Mode-Automata.It has been designed so that only small extensions to Modelica 3.1 are needed.The algorithms are sketched that are used to guarantee consistent graphs that give a limited number of event iterations.Furthermore, it is shown how a symbolic verifier can be used to guarantee additional properties of state machines.