Active flutter suppression of a multiple-actuated-wing wind tunnel model

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.