Fuzzy gain scheduling using output feedback for flutter suppression in unmanned aerial vehicles with piezoelectric materials

This research addresses the modeling, analysis, and control of flutter, in a high order nonminimum phase aeroservoelastic UAV system with Piezoelectric single servo input. Flutter suppression requires output feedback supplied by four accelerometer sensor readings. Linear time invariant plant models vary with the exogenous parameter, velocity. The fuzzy gain scheduling control strategy, in conjunction with Linear Quadratic Gaussian regulation, with prescribed degree of stability, at nominal operating conditions, produces interpolated controller and observer gains over a uniform grid of operating velocities. "Worst case" highest velocity eigenvalues are used for stabilization. Simulations of augmented closed-loop systems show settling times ranging between 0.2 s and 0.4 s. Control effort is uniform and converges to 0 rad within 0.1 s. The end result is a robust global controller that suppresses flutter over the entire velocity envelope.