Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2000. / Includes bibliographical references (p. 215-223). / A new concept for retrofitting a reconfiguration module to an existing control law is reported in this thesis. The concept is motivated by the need for low cost, add-on modules that improve air safety in the existing fleet of civil air transport vehicles. A direct adaptive approach that accommodates control surface nonlinearities is adopted, which uses a slowly adapting model of the closed-loop aircraft as the reference model. The motivation, benefits, and components of the architecture are presented. In addition, the issues of control surface magnitude and rate saturation are addressed. A proof of stability is outlined for input-error adaptation when position and rate saturation are present. The reconfiguration architecture is demonstrated using an F/A-18 and a generic transport nonlinear simulator. General issues associated with commercial transport reconfiguration are highlighted. In both the longitudinal and directional axes, the control surfaces are not well balanced from a reconfiguration viewpoint. As a result, a novel reconfiguration control allocation scheme was devised that blends in all the control effectors in a given axis to perform the reconfiguration task. The simulation results revealed that the reconfiguration architecture does provide reconfiguration functionality for a wide variety of control surface failures. The reconfiguration potential is illustrated through comparisons of post-failure performance with and without reconfiguration via non-linear simulations. Additionally, comparisons between post-failure performance and nominal performance are made through non-linear simulations, closed-loop frequency responses, and aircraft handling qualities. For all of the failure scenarios illustrated, the simulation results showed that the aircraft without reconfiguration departs; with reconfiguration, nominal performance is achieve provided that adequate control authority exists post-failure. / by Jerry M. Wohletz. / Ph.D.
| Identifer | oai:union.ndltd.org:MIT/oai:dspace.mit.edu:1721.1/9264 |
| Date | January 2000 |
| Creators | Wohletz, Jerry M. (Jerry Matthew), 1971- |
| Contributors | James D. Paduano., Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics., Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. |
| Publisher | Massachusetts Institute of Technology |
| Source Sets | M.I.T. Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 224 p., 13076272 bytes, 13076030 bytes, application/pdf, application/pdf, application/pdf |
| Rights | M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission., http://dspace.mit.edu/handle/1721.1/7582 |
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