Fuzzy logic control for nonlinear free vibration of composite plates with piezoactuators

A study of the use of fuzzy logic control techniques to suppress the large amplitude free vibrations of composite plates with embedded piezoelectric actuators is presented. The finite element method is employed to obtain the nonlinear dynamic equations of the plate vibration. The von-Karmen large deflection plate theory is used in the nonlinear finite element formulation. The finite element model considers both structural nodal degrees of freedom and electrical degrees of freedom for composite plates with embedded piezoelectric actuators. The modal reduction method for nonlinear structure dynamic equations using the structure linear modes is used to reduce the finite element nonlinear equations into a set of coupled general Duffing equations with much smaller degrees of freedom. Fuzzy logic control laws are used to actively suppress the plate nonlinear vibration. Employing such control techniques is more robust than the conventional control techniques due to the inherent nonlinearity and uncertainty of the fuzzy logic control algorithms. Self-organizing fuzzy logic controller which is capable of modifying its control policy based on a given performance measure is also employed. Simulation results are given for a simply supported graphite/epoxy composite plate undergoing free vibration with different initial conditions.