Optimal sizing and placement of piezo actuators for active flutter suppression

The purpose of this paper is to design an active control system for flutter suppression of laminated plate wing model by using the segmented piezo actuators. It describes the investigations pertaining to the optimal size, thickness and locations of piezo actuators on laminated plate-wing structure for flutter suppression. The analysis for laminated composite wing model is conducted by Ritz solution technique, which represents the displacement on the plate in terms of the power series in spanwise and chordwise directions. The active control system design for flutter suppression requires the equation of motion to be expressed in a linear time-invariant state-space form. Doublet lattice method is used to compute unsteady aerodynamic forces, which are approximated as the transfer functions of the Laplace variable by Minimum State method combined with optimization technique. To design control system, linear quadratic regulator theory with output feedback is considered in this study. The feedback control gains are obtained by solving coupled nonlinear matrix equations via numerical optimization routines. The optimal geometry of piezo actuators which minimizes the control performance index is determined by optimization technique referred to as the sequential linear programming method. Numerical results shows a substantial saving in control effort compared with the initial model.