Modelling of System Properties in a Modelica Framework

Abstract

In order to improve the engineering processes and especially the corresponding verification and validation phases, this article deals with the modeling of system properties in a Modelica framework. The term “property” is intended here to be generic and refers to a system requirement or limitation as well as a validity domain of a model. The choice of the Modelica language is justified by a desire to use its equation-based feature to model system properties in an unambiguous and explicit way. Besides, choosing only one formalism to describe the system properties and the physical equations of the model should ease the expression of the model validity domains. After having introduced several theoretical concepts to formally describe a system property, the development of a dedicated library is explained and illustrated on an industrial example taken from the aeronautics domain. Some checks of system properties are thus performed by co-simulating behavioral and properties models. Finally, some extensions of the Modelica language are advocated in order to improve the applicability range and efficiency of properties modeling for complex systems, and especially to increase the rigor of their validations by enabling formal proofs.