|Robust Digital Implementation of Fuzzy Control for Uncertain Systems and Its Application to Active Magnetic Bearing System
Hwa Chang Sung, Jin Bae Park, Young Hoon Joo*, and Kuo Chi Lin
International Journal of Control, Automation, and Systems, vol. 10, no. 3, pp.603-612, 2012
Abstract : In this paper, we propose the robust digital control for active magnetic bearing (AMB) systems. For achieving the robust stability, we deal with the uncertainties of the given system based on the Takagi-Sugeno (T-S) fuzzy model. Also, in order to solve the digital implementation for real plants, this paper presents a robust intelligent digital redesign (IDR) method. The term IDR involves converting an analog controller into an equivalent digital one in the sense of state-matching. The uncertainties in the plant dynamics is shown in the IDR condition by virtue of the pade and inverse-pade approximation method. Also, the robust stability property is preserved by the proposed method. The sufficient conditions for robust controller are obtained in terms of solutions to linear matrix inequalities (LMIs). Finally, simulation results for two AMB systems are demonstrated to visualize the feasibility of the proposed method.
Keyword : Active magnetic bearing (AMB), intelligent digital redesign (IDR), linear matrix inequalities (LMIs), Pade and inverse-Pade approximation, Takagi-Sugeno (T-S) fuzzy model.