NASA's Space Launch System (SLS) Flight Control System (FCS) includes an Adaptive Augmenting Control (AAC) component which employs a multiplicative gain update law to enhance the performance and robustness of the baseline control system for extreme off-nominal scenarios. The SLS FCS algorithm including AAC has been flight tested utilizing a specially outfitted F/A-18 fighter jet in which the pitch axis control of the aircraft was performed by a Non-linear Dynamic Inversion (NDI) controller, SLS reference models, and the SLS flight software prototype. This paper describes test cases from the research flight campaign in which the fundamental F/A-18 airframe structural mode was identified using post-flight frequency-domain reconstruction, amplified to result in closed loop instability, and suppressed in-flight by the SLS adaptive control system.
In-Flight Suppression of an Unstable F/A-18 Structural Mode Using the Space Launch System Adaptive Augmenting Control System
2015
14 pages
Report
Keine Angabe
Englisch
Civil Engineering , Aircraft , In-flight monitoring , Damping , Unsteady aerodynamics , F-18 aircraft , Spacecraft launching , Adaptive control , Augmentation , Flight control , Algorithms , Flight tests , Fast fourier transformations , Vibration mode , Airfoil oscillations , Structural vibration , Bandpass filters , Time domain analysis , Direct numerical simulation , Nonlinearity , Prototypes , Feedback control , Controllers , Frequency measurement , Amplification , Computer programs , Dynamic models