This paper presents a numerical and experimental investigation on active flutter suppression of a swept-back cantilevered lifting surface using piezoelectric (PZT) actuation. A finite element method, a panel aerodynamic method, and the minimum state-space realization are involved in the development of the equation of motion in state-space, which is efficiently used for the analysis of the system and design of control laws with a modern control framework. PZT actuators, bonded symmetrically on the plate, are optimally grouped into two equivalent actuator sets using genetic algorithms to enhance controllability. H-2(-) and mu-synthesized control laws are designed and the flutter suppression performance is evaluated via wind tunnel testing. In the M-synthesis design, a simple parametric uncertainty model is used to take into account the system changes with respect to airflow speed. Both controllers show comparable flutter suppression performance around the flutter point. However, the p-synthesized controller shows improved behavior over a wide flow speed range. (c) 2005 Elsevier Ltd. All rights reserved.