Robustness Analysis of AMB Suspension

This paper deals with the robustness analysis of the active magnetic bearing suspension. First, finite element method is used to find the variations of the bearing parameters. Based on this analysis, a plant description is proposed, where the uncertainties are modeled as uncertain "almost" diagonal and real gain matrices. For the robustness analysis, a special way of constructing a generalized Nyquist diagram is proposed. This diagram gives nonconservative stability margin predictions and is a useful tool for synthesis purposes. Finally, the test machine is analyzed using the proposed method.