Automated formula manipulation supports object-oriented continuous-system modeling

Automated formula manipulation is central to object-oriented continuous-system modeling. Such techniques are needed to a) solve the causality assignment problem in modeling any kind of energy transducer, b) generate the equations that result from the couplings between different objects, c) automatically reduce higher index models, and d) take care of algebraic loops that often result from subsystem couplings, and that also occur from the reduction of higher index models. A new tool, Dymola, imple-ments all of these formula manipulation techniques, and can be used to generate state-space models in a variety of different simulation languages (ACSL, DESIRE, DSblock, Simnon, and SIMULINK). Simulation Languages The first generation of digital continuous-system simulation languages were designed to resemble analog compute