Weighted balanced model reduction of a flexible structure

The determination of structural modes which are important for control is a major issue in the field of active control of flexible structures. The paper is devoted to the application of an iterative model reduction proposed by Enns (1984) to a 2-DOF flexible pointing system. The framework of weighted balanced reduction is first recalled, together with the choice of weights preserving closed-loop stability. An illustrative example and the control design methodology are then presented. Enns´ iterative reduction procedure is applied and the results obtained are reviewed. Improvements are proposed to trade off model order and controller robustness