Controle ativo de estruturas compósitas inteligentes na presença de incertezas

Abstract

This work addresses the use of robust techniques for the active control of composite structures coupled with piezoelectric actuators. The design of controllers uses the approach of linear matrix inequalities (LMI), which facilitate the inclusion of polytopic type uncertainties in the design of robust controllers. The proposal is to compare two types of robust controllers applied to vibration control of a flexible composite cantilever beam subjected to polytopic uncertainties. H and linear quadratic regulator (LQR) controllers, both with state-feedback obtained by observers and designed with the use of LMI are chosen. The composite laminate model considering the electromechanical coupling of piezoelectric materials is obtained using the finite element method (FEM). The reduction method based on balanced realization is used for the compatibilization of model dimension to the control procedures. Two kinds of uncertainties are considered: the first is related to the direction of the fibers in each layer of composite material, which commonly occurs during the manufacturing. The second type pertains the non-ideal stiffness of the clamping device, by means of the reduction of the elements directly linked to the clamp. The results, obtained through numerical simulations in MATLAB® environment, are discussed with regard to the robustness of the control techniques investigated.