Enforcing model composability in Modelica

Abstract

Modelica provides intuitive constructs to create and group model definitions. However, models themselves do not compose. In other words, the connection of type-compatible and locally balanced submodels does not generally yield a valid (e.g., balanced, structurally non-singular) model. Starting from simple examples of such invalid models (resulting from commonly encountered situations when using Modelica), this paper explains how those problems could be avoided by introducing a safer notion of physical connector, similar in some aspects to the VHDL-AMS notion of terminal. An extension of the notion of connection is also presented, providing new opportunities to make efficient use of ideal models in Modelica.

Interactive Programmatic Modeling

“…To dene robust semantics for such languages with acausal connections is an active research area, in particular since discrete changes can change the DAE index of the model. For instance, see the paper by Furic [25] that describes several problems that exist in the standardized Modelica language.…”

Operational Semantics for a Modular Equation Language

“…Kalman's operators V, D and L inspired ∆ and I in this work. An early prototype of this work was developed using an implementation (by the apache commons project 3 ) of Kalman's Derivative Structures. Also the idea of precomputed basic operations for multiplication and composition is based on that implementation.…”

“…by Zimmer [13] and Furic [3]. The former preferred an after-compilation approach to "rescue" as much modularity as possible, while the latter restricts the modeling formalism itself in a way that renders most symbolic manipulation needless.…”

Node-Based Connection Semantics for Equation-Based Object-Oriented Modeling Languages

“…2.3). Furic [12] proposes an alternative connection semantics for Modelica. The main objective is to make models compose better and to support structural dynamism.…”