U.P.B. Sci. Bull., Series D, Vol. 72, No. 2, 2010 ISSN 1454-2358 ROBUST ACTIVE CONTROL LAW WITH INTERNAL MODEL FOR VIBRATION ATTENUATION Eliza MUNTEANU 1 , Ioan URSU 2 Lucrarea de faţă continuă o serie de cercetări ale autorilor ([1], [2]) în domeniul controlului activ al vibraţiilor pentru un model de aripă din material compozit prin utilizarea de actuatori piezo de tip MFC (Macro-Fiber-Composite). Caracteristicile de robusteţe ale controlului optimal LQR (Linear Quadratic Regulator) sunt recuperate de către filtrul Kalman aplicând o construcţie specială a estimatorului. Legea de control obţinută poartă numele de LQG/LTR (Linear Quadratic Gaussian/ Loop Transfer Recovery). Pe de altă parte, introducerea unui model intern în compensatorul sistemului oferă un plus de robusteţe şi performanţe remarcabile. The present work continues some recent researches of the authors ([1], [2]) in the vibration active control domain for a composite wing model by using MFC (Macro-Fiber-Composite) piezo actuators. The robustness characteristics of the optimal control LQR (Linear Quadratic Regulator) are recovered by the Kalman filter applying a special construction for the estimator. The obtained control law is called LQG/LTR (Linear Quadratic Gaussian/ Loop Transfer Recovery). Moreover, including an internal model in the compensator of the system confers more robustness properties and remarkable performances. Keywords: robust active control, composite wing, MFC piezo actuators 1. Introduction In general, to meet the regulatory requirements for any certified aircraft to be free of wing dangerous vibrations, one can use either passive or active control techniques. The first ones increase the structure weight and in certain situations are not feasible. The active techniques enhance dynamic behavior of the wing, without redesign and adding mass; nowadays, these are used both for flutter suppression and structural load alleviation. Thus, herein our target concerns the obtaining of a robust active control law, based on the LQG/LTR synthesis [3], for a piezo smart composite wing. Moreover, to increase the robustness characteristics and the performance of the designed control law we incorporate an 1 PhD Student eng., Advanced Studies and Research Center, România, email: eliza.munteanu@asrc.ro 2 PhD. math., National Institute for Aerospace Research “Elie Carafoli”, România, email: iursu@incas.ro