Commercial Aircraft
Corporation of China, Ltd (COMAC)and Chinese Scholarship Council. / The aim of this thesis is to develop a real time PIO detection and mitigation system that
consists of a detector based on short time Fourier transform(STFT) and autoregressive
model(ARX) with exogenous inputs, together with an adaptive controller based mitigation
system. The system not only detects the traditional PIO characteristics but also focuses on
the trend of pilot behaviour by calculating the rate of change in the open loop crossover
frequency. In the detection system, a sliding windowed STFT method was applied to
identify the frequency and phase characteristics of the system via processing the signal of
pilot input and aircraft state. An ARX model was also applied to get the rate of change
of the crossover frequency. After detection, a PIO cue was shown on the primary flight
display. A scheduled gain controller was coupled to provide PIO mitigation by varying
stick input gain.
Compensatory and tracking tests for the evaluation of this system were performed using
a quasi-linear Boeing-747 aircraft model including nonlinear command gearing and actuator
rate-limiting. Bandwidth and Gibson criteria were used to design PIO prone control
laws for system evaluation experiments. Results from PIO tests conducted on desktop
PCs were presented. These were analyzed and compared with those obtained from implementing
the Real-time Oscillation Verifier module available in literature.
| Identifer | oai:union.ndltd.org:CRANFIELD1/oai:dspace.lib.cranfield.ac.uk:1826/7998 |
| Date | 12 1900 |
| Creators | Liu, Qingling |
| Contributors | Cooke, A. K., Mudassir Lone, M. |
| Publisher | Cranfield University |
| Source Sets | CRANFIELD1 |
| Language | English |
| Detected Language | English |
| Type | Thesis or dissertation, Masters, MSc by Research |
| Rights | © Cranfield University 2011. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright owner. |
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