In this study, a multi-input/multi-output（MIMO） time-delay feedback controller is designed to actively suppress the flutter instability of a multiple-actuated-wing（MAW） wind tunnel model in the low subsonic flow regime. The unsteady aerodynamic forces of the MAW model are computed based on the doublet-lattice method（DLM）. As the first attempt, the conventional linear quadratic-Gaussian（LQG） controller is designed to actively suppress the flutter of the MAW model. However, because of the time delay in the control loop, the wind tunnel tests illustrate that the LQG-controlled MAW model has no guaranteed stability margins. To compensate the time delay, hence, a time-delay filter, approximated via the first-order Pade approximation, is added to the LQG controller. Based on the time-delay feedback controller, a new digital control system is constructed by using a fixed-point and embedded digital signal processor（DSP） of high performance. Then, a number of wind tunnel tests are implemented based on the digital control system.The experimental results show that the present time-delay feedback controller can expand the flutter boundary of the MAW model and suppress the flutter instability of the open-loop aeroelastic system effectively.
