Abstract: Considering system modeling uncertainty of active magnetic bearing (AMB), the robust control model for racial AMB is built, and a method is presented to design a m robust controller with structured singular value as an optimal indicator. On the basis of analyzing AMB, the performance robustness problem is transformed into the stability robustness problem of the augmented system by introducing fictive uncertainty. It can be solved with D-K iteration. The stability robustness and the performance robustness are obtained simultaneously to reduce designing conservation. The simulative waveforms of control system are accomplished to check the robustness of H∞ control and μ control for AMB system under different circumstances of uncertainty and external disturbance by using Matlab, and the comparison between H∞ control and μ control is performed. The simulation results show that the robust control for AMB based on μ synthesis theory has better dynamic characteristic, stronger stability robustness and performance robustness to system model uncertainty and the external disturbances can be con-trolled effectively, with respect to the system model perturba-tions in the allowed range.

Key words: Active magnetic bearing(AMB), m synthesis, Model uncertainty, Robust control, Structured singular value