Conference article

In modeling and simulation of dynamical processes frequently higher index differential-algebraic equations (DAEs) arise. Since an attempt to solve higher-index DAEs directly yields several numerical problems, a regularization in combination with a robust and efficient integration is required. \qualidaes\ is a DAE solver designed to make explicit use of such a regularization. It allows for the solution of over-determined quasi-linear DAEs of the form $M(x,t)\dot{x}=f(x,t)$, $0=g(x,t)$. Such DAEs arise naturally if a quasi-linear DAE is regularized by augmentation with the set of its (hidden) constraints. General DAEs can be brought into the quasi-linear form. To this end, \modelica\ equations can be transformed into the specific input format expected by \qualidaes. This transformation can be implemented in a functional style and yields a non-trivial result. Additionally it provides an on-the-fly solution for the occurrence of higher-order derivatives.

Differential-Algebraic Equations; Quasi-Linear; Modelica; Translation; Regularization; Solver; QUALIDAES