Design of a Nonlinear Adaptive Filter for Suppression of Shuttle Pilot-Induced Oscillation Tendencies
Smith, John W. and Edwards, John W. (1980) Design of a Nonlinear Adaptive Filter for Suppression of Shuttle Pilot-Induced Oscillation Tendencies. Technical Report NASA TM-81349, Research Engineering, NASA Dryden Flight Research Center.
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Abstract
On the final flight of the space shuttle's approach and landing tests, a longitudinal pilot-induced oscillation (PIO) was experienced just prior to touchdown. Subsequent analysis indicated that the source of the problem was a combination of poor basic handling qualities aggravated by time delays through the digital flight control computer and rate limiting of the elevator actuators due to high pilot gain. A nonlinear PIO suppression (PIOS) filter was designed and developed to alleviate the vehicle's PIO tendencies by reducing the gain in the command path. From analytical and simulator studies it was shown that the PIOS filter, in an adaptive fashion, can attenuate the command path gain without adding phase lag to the system. With the pitch attitude loop of a simulated shuttle model closed, the PIOS filter increased the gain margin by a factor of about two.
| EPrint Type: | NASA Technical Memorandum |
|---|---|
| Keywords: | Handling qualities |
| Subjects: | (01 - 09) Aeronautics: (08) Aircraft Stability And Control Aircraft/Project: Space Shuttle Orbiter |
| ID Code: | 669 |
| Deposited On: | 09 Febuary 2006 |
| Additional Information: | 31 pages. |
