Robust Initialization of Differential Algebraic Equations

This paper describes a new solution method applied to the problem initializing DAEs using the Modelica lan-guage. Modelica is primarily an object-oriented equa-tion-based modeling language that allows specification of mathematical models of complex natural or man-made systems. Major features of Modelica are the mul-tidomain modeling capability and the reusability of model components corresponding to physical objects, which allow to build and simulate highly complex sys-tems. However, initializing such models has been quite cumbersome, since initial equations have to be pro-vided at the system level, where the user needs to know details on the underlying transformation and index-reduction algorithms, that in general are applied to simulate a Modelica model. .