μ-synthesis of an electromagnetic suspension system

The authors discuss the μ-synthesis of an electromagnetic suspension system. The issue of modeling a real physical electromagnetic suspension system is discussed. A nominal model as well as a set of models in which the real system is assumed to reside is derived. Different model structures and possible model parameter values are fully employed to determine unstructured additive plant perturbation, which directly yield the uncertainty weighting. Based on the set of plant models, the robust performance control objectives are defined. Using the μ-Analysis and Synthesis Toolbox, use is made of the D-K iteration approach for the controller design. Implementing the controller with a digital signal processor μ PD77230, experiments are carried out to evaluate the robust performance of this design. It was shown that the closed-loop system with the μ-controller achieves not only nominal performance and robust stability, but also robust performance