Abstract
The F/A-18 Hornet aircraft with the original flight control law exhibited a nonlinear out-of-control phenomenon known as the falling-leaf mode. This unstable mode was suppressed by modifying the control law. This paper employs the falling-leaf phenomenon as an example to investigate the applicability of linear analysis tools for detecting inherently nonlinear phenomenon.Ahigh- fidelity nonlinear model of the F/A-18 is developed for controller analysis using F/A-18 High-Alpha Research Vehicle aerodynamic data in the open literature. A variety of linear analysis methods are used to investigate the robustness properties of the original (baseline) and the revised F/A-18 flight control law at different trim points. Classical analyses, e.g., gain and phase margins, do not indicate a significant improvement in robustness properties of the revised control law over the baseline design. However, advanced robustness analyses, e.g., μ analysis, indicate that the revised control law is better able to handle the cross-coupling and variations in the dynamics than the baseline design.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 57-72 |
| Number of pages | 16 |
| Journal | Journal of Guidance, Control, and Dynamics |
| Volume | 34 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2011 |
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Susceptibility of F/A-18 flight controllers to the falling-leaf mode : Linear analysis. / Chakraborty, Abhijit; Seiler Jr, Peter J; Balas, Gary J.
In: Journal of Guidance, Control, and Dynamics, Vol. 34, No. 1, 01.01.2011, p. 57-72.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Susceptibility of F/A-18 flight controllers to the falling-leaf mode
T2 - Linear analysis
AU - Chakraborty, Abhijit
AU - Seiler Jr, Peter J
AU - Balas, Gary J.
PY - 2011/1/1
Y1 - 2011/1/1
N2 - The F/A-18 Hornet aircraft with the original flight control law exhibited a nonlinear out-of-control phenomenon known as the falling-leaf mode. This unstable mode was suppressed by modifying the control law. This paper employs the falling-leaf phenomenon as an example to investigate the applicability of linear analysis tools for detecting inherently nonlinear phenomenon.Ahigh- fidelity nonlinear model of the F/A-18 is developed for controller analysis using F/A-18 High-Alpha Research Vehicle aerodynamic data in the open literature. A variety of linear analysis methods are used to investigate the robustness properties of the original (baseline) and the revised F/A-18 flight control law at different trim points. Classical analyses, e.g., gain and phase margins, do not indicate a significant improvement in robustness properties of the revised control law over the baseline design. However, advanced robustness analyses, e.g., μ analysis, indicate that the revised control law is better able to handle the cross-coupling and variations in the dynamics than the baseline design.
AB - The F/A-18 Hornet aircraft with the original flight control law exhibited a nonlinear out-of-control phenomenon known as the falling-leaf mode. This unstable mode was suppressed by modifying the control law. This paper employs the falling-leaf phenomenon as an example to investigate the applicability of linear analysis tools for detecting inherently nonlinear phenomenon.Ahigh- fidelity nonlinear model of the F/A-18 is developed for controller analysis using F/A-18 High-Alpha Research Vehicle aerodynamic data in the open literature. A variety of linear analysis methods are used to investigate the robustness properties of the original (baseline) and the revised F/A-18 flight control law at different trim points. Classical analyses, e.g., gain and phase margins, do not indicate a significant improvement in robustness properties of the revised control law over the baseline design. However, advanced robustness analyses, e.g., μ analysis, indicate that the revised control law is better able to handle the cross-coupling and variations in the dynamics than the baseline design.
UR - http://www.scopus.com/inward/record.url?scp=78650964749&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=78650964749&partnerID=8YFLogxK
U2 - 10.2514/1.50674
DO - 10.2514/1.50674
M3 - Article
VL - 34
SP - 57
EP - 72
JO - Journal of Guidance, Control, and Dynamics
JF - Journal of Guidance, Control, and Dynamics
SN - 0731-5090
IS - 1
ER -