Model-based Embedded Control using Rosenbrock Integration Methods

Abstract

Directly generating controller code from models is important for advanced model-based design. This paper describes how Dymola can generate embedded C-code from Modelica models, designed to be easy to embed, with care about minimal foot-print, traceability, and straightforward integration in embedded platforms and gives actual application examples. The paper focuses on using Rosenbrock methods for index-1 problems (instead of the normal transformation to index 0) that allows Dymola to handle stiff systems in a way that both is theoretically sound and has an upper bound on the execution time per sample. The stiff systems in the control system often occur due to using an inverse (simplified) model of the real plant in the controller. A nonlinear feedforward controller and a controller with feedback linearization, both applying an inverse model, demonstrate the proposed process by using Rosenbrock methods for embedded code generation.