Modeling and simulating cyber-physical systems using CyPhySim

This paper describes an open-source simulator for cyberphysical systems called CyPhySim that is based on Ptolemy II. This simulator supports classical (Runge-Kutta) and quantized-state simulation of ordinary differential equations, modal models (hybrid systems), discrete-event models, the Functional Mockup Interface (FMI) for model-exchange and co-simulation, discrete-time (periodic) systems, and algebraic loop solvers. CyPhySim provides a graphical editor, an XML file syntax for models, and an open API for programmatic construction of models. It includes an innovation called "smooth tokens," which allow for a blend of numerical and symbolic computation, and for certain kinds of system models, dramatically reducing the computation required for simulation.