Flutter Suppression for a Prototype Wing - Numerical Modeling, Control Law Design, and Experimental Results

Abstract

The paper presents a flutter suppression control design for a prototype wing. The present approach includes numerical modeling of aeroservoelastic system, reduced-order modeling, and robust control law design to arrive at an active flutter suppression control. The resulting control is implemented and tested for its effectiveness in wind-tunnel experiments. Computational aeroelastic techniques 11 and nonlinear reduced-order modeling methods 16, 17 are applied to obtain a mathematical representation of the system useful for control law design. Robust control design follows the H ∞ fixed-order output-feedback (HIFOO) controller by means of a non-convex local optimization algorithm that offers the advantage of stability guarantee when a solution is found, and handling of non-smooth gradients encountered in non-convex problems. 5, 6, 15 The developed flutter suppression control design was implemented and tested with a specially designed wind-tunnel wing model. 14 Wind tunnel tests of closed-loop control confirm the validity of the present approach, where more than 90% attenuation of LCO has been recorded.

Synthesis of an active flutter suppression system in the transonic domain using a computational model

“…Computations of both the control laws and the TSD aerodynamics were repeated for a range of cruise Mach numbers from 0.5 to 0.95. The results obtained in the open- and closed-loop cases were qualitatively similar to those of Lai and Lum (49) , who presented a flutter prediction approach using a combination of full-order computational aeroelastic techniques and reduced-order modelling methods, which were applied to closed-loop and nonlinear Hopf bifurcation analysis of the benchmark transonic aeroelastic AGARD 445.6 wing.…”