Modeling Continuous System Dynamics in SysML

In this paper, we present a formal approach to modeling continuous system dynamics in SysML using differential algebraic equations (DAE’s). To support model-based design, the Object Management Group has recently developed the Systems Modeling Language (OMG SysML™). The language is well-suited for modeling many different aspects of large-scale, multidisciplinary engineering projects. It allows systems designers to capture information concerning system requirements, tests, structures, functions, and behaviors. However, SysML lacks explicit support for modeling continuous system dynamics using DAE’s. Such models are important for representing system behavior resulting from energy or signal exchange between system components. We introduce support for modeling system dynamics in the form of a language mapping between SysML and Modelica, an equation-based, object-oriented behavioral simulation language. The bidirectional mapping provides support for creating system dynamics models in SysML that can exist alongside other SysML information models, but that can also be transformed into executable simulations by a Modelica solver. To illustrate the approach, we provide an example SysML model of a hydraulic pump.