Autoland controllers are prevalent for both large and small/micro unmanned aerial vehicles,
but very few are available for medium sized unmanned aerial vehicles. These
vehicles tend to have limited sensors and instrumentation, yet must possess good
performance in the presence of modeling uncertainties, and exogenous inputs such
as turbulence. Quantitative Feedback Theory is an attractive control methodology
for this application, since it provides good performance and robustness for systems
with structured model uncertainties. It has been successfully applied to many aircraft
problems, but not to automatic landing, and only inner-loop synthesis has been
presented in the literature. This paper describes the synthesis and development of an
automatic landing controller for medium size unmanned aerial vehicles, using discrete
Quantitative Feedback Theory. Controllers for the localizer, glideslope tracker, and
automatic flare are developed, with a focus on the outer-loops synthesis. Linear, non
real-time six degree-of-freedom Monte Carlo simulation is used to compare the Quantitative
Feedback Theory controller to a baseline Proportional-Integral controller in
several still air and turbulent landing scenarios. The Quantitative Feedback Theory
controller provides performance similar to the Proportional-Integral controller in still
and in turbulent air. Both controllers show similar robustness to turbulence, but the
Quantitative Feedback Theory controller provides significantly better robustness to
model uncertainties in turbulent air as well as to sensor characteristics in turbulence.
Based on the results of the paper, the QFT controller is a promising candidate for an autoland controller.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/5960 |
| Date | 17 September 2007 |
| Creators | Wagner, Thomas William, Jr. |
| Contributors | Valasek, John |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 3330971 bytes, electronic, application/pdf, born digital |
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