Browsing by Subject "ILAF"
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Item Flight-Dynamics, Flutter, and Active-Flutter-Suppression Analyses of a Flexible Flying-Wing Research Drone(As presented at the NASA Armstrong Flight Research Center Edwards AFB, CA, 2015-06-15) Schmidt, DavidItem Flight-Dynamics, Flutter, and Active-Flutter-Suppression Analysis of a Flexible Flying-Wing Research Drone(Aerospace Flutter and Dynamics Council (AFDC) Meeting, Spring 2015, 2015-04-16) Schmidt, DavidItem Stability Augmentation and Active Flutter Suppression of a Flexible Flying-Wing Drone(2015-05-19) Schmidt, DavidIntegrated control laws are developed for stability augmentation and active flutter suppression (AFS) of a flexible, flying-wing drone. The vehicle is a 12-pound unmanned, flying- wing research aircraft with a 10 ft wingspan. AFS is flight critical since the subject vehicle is designed to flutter within its flight envelope. The critical flutter condition involves aeroelastic interactions between the rigid-body and elastic degrees of freedom; hence the control laws must simultaneously address both rigid-body stability augmentation and flutter suppression. The control-synthesis approach is motivated by the concept of Identically Located Force and Acceleration (ILAF), successfully applied on some previous operational aircraft. Based on the flutter characteristics and on conventional stability-augmentation concepts, two simple loop closures are suggested. It is shown that this control architecture robustly stabilizes the body- freedom-flutter condition, increases the damping of the second aeroelastic mode (which becomes a second flutter mode at higher velocity), and provides reasonably conventional vehicle pitch- attitude response. The critical factors limiting the performance of the feedback system are identified to be the bandwidth of the surface actuators and the pitch effectiveness of the control surfaces.