Abstract
The paper evaluates the influence on off-nominal flight dynamics charac- teristics when closing the loop on an aircraft model with a feedback feedfor- ward control law. Of particular interest is the departure/upset behaviour of the closed-loop system near stall. The study vehicle is the NASA Generic Transport Model (GTM) and both fixed-gain and gain-scheduled versions of a LQR-PI controller are evaluated. The differences in effectiveness of the controllers are first demonstrated using time responses to fixed com- mands. Then, bifurcation analysis is used to characterize spiral and spin behaviour of the open-loop system, after which the influence of closing the loop on the system bifurcation diagram is shown. This yields an under- standing of the dynamics underlying both the open-loop and closed-loop system under off-nominal conditions, and hence a means of assessing the effects of varying the controller gains on the upset tendencies of the aircraft.
Original language | English |
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Title of host publication | Proceedings of the 2013 AIAA Atmospheric Flight Mechanics Conference |
Publisher | American Institute of Aeronautics and Astronautics Inc. (AIAA) |
Number of pages | 23 |
DOIs | |
Publication status | Published - Aug 2013 |
Event | AIAA Atmospheric Flight Mechanics (AFM) Conference - Boston, MA, United States Duration: 19 Aug 2013 → 22 Aug 2013 |
Conference
Conference | AIAA Atmospheric Flight Mechanics (AFM) Conference |
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Country/Territory | United States |
City | Boston, MA |
Period | 19/08/13 → 22/08/13 |
Keywords
- Aircraft dynamics
- Airliner upset
- Bifurcation analysis
- Control laws