An Extension of the Systems Modeling Language for Physical Interaction and Signal Flow Simulation

Computer-interpretable representations of system structure and behavior are at the center of developing today's complex systems. Systems engineers create and review these representations using graphical modeling languages that capture requirements, designs, and tests (such as the Systems Modeling Language, SysML). However, these languages must be used in conjunction with analysis tools, in particular, with simulators for physical interaction and numeric signal flow based on ordinary and algebraic differential equation solvers. These kind of simulation tools are often used separately from system modeling tools, leading to inconsistencies that require additional work to eliminate, preventing multidisciplinary concerns from being reflected in the overall system design. As a result, there is an increasing need for integrating physical interaction and signal flow simulation tools and languages into system modeling under a single framework. In this article, we first present an abstraction of the constructs and semantics these simulation tools and languages have in common, based on earlier reviews. Then, we compare SysML to our simulation abstraction to find the parts of SysML closest to simulation modeling, and to identify simulation concepts missing from SysML. This leads to extensions of SysML to bridge the gaps, illustrated with an example application. Next, we address issues in translating extended SysML models to common simulation tools and languages, including the differences between them. Finally, we validate the approach by applying the extension to an example SysML model, automating the translations in software, and showing that the results execute the same way on different simulation platforms.