Robustness analysis of an L 1 adaptive controller

Peter Seiler, Andrei Dorobantu, Gary Balas

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations


NASA's Generic Transport Model (GTM) is a remote-controlled, 5.5 percent scale commercial aircraft. An L 1 adaptive controller was recently designed and flight tested on the GTM. Oscillations in the elevator command were observed at 1.4 to 2 Hertz during the first flight test in September 2009. In most flight conditions the L 1 adaptive controller can be approximated by a linear time-invariant system. Thus linear analysis tools can be used to assess the performance and robustness of the feedback system with the L 1 controller. The initial L 1 design met the NASA requirement for 60 msec of time delay margin. However, the linear analysis indicates that the margin requirements were insufficient due to inaccurate models that were available at the time of the first flight test. A revised L 1 controller has significantly larger margins and demonstrated good performance during subsequent flight tests.

Original languageEnglish (US)
Title of host publicationAIAA Guidance, Navigation, and Control Conference
StatePublished - 2010
EventAIAA Guidance, Navigation, and Control Conference - Toronto, ON, Canada
Duration: Aug 2 2010Aug 5 2010

Publication series

NameAIAA Guidance, Navigation, and Control Conference


OtherAIAA Guidance, Navigation, and Control Conference
CityToronto, ON

Bibliographical note

Funding Information:
This research was supported under the NASA Langley NRA contract NNH077ZEA001N entitled “Analytical Validation Tools for Safety Critical Systems”. The technical contract monitor is Dr. Christine Belcastro. The authors gratefully acknowledge Irene Gregory, Naira Hovakimyan, and Enric Xargay for

Fingerprint Dive into the research topics of 'Robustness analysis of an L <sub>1</sub> adaptive controller'. Together they form a unique fingerprint.

Cite this