Unified Pilot-Induced Oscillation Theory, Volume 3. PIO Analysis Using Multivariable Methods
Unified Pilot-Induced Oscillation Theory, Volume 3. PIO Analysis Using Multivariable Methods

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Publisher:

Published: 1995

Total Pages: 110

ISBN-13:

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This work was conducted as part of a USAF initiative to develop a comprehensive theory to predict pilot-induced oscillation (PIO) tendencies due to the combined effect of all influencing elements. A PIO is a very complicated phenomenon stemming from a dynamic interaction between the pilot and the aircraft. When tight control is required of the pilot, an undesired oscillation can result. However, the adaptive nature of the human pilot makes such oscillations difficult to predict. This report describes an analysis method capable of predicting PIO tendencies due to several simultaneous dynamic factors. A unified approach involving pilot modeling, stability robustness analysis, and multivariable describing function analysis is applied to the problem of identifying aircraft with PIO tendencies. The approach is shown to have ties to existing PIO criteria and is successfully applied to the prediction of PIO tendencies of the M2-F2 lifting body.

Flight Test Evaluation of Techniques to Predict Longitudinal Pilot Induced Oscillations
Flight Test Evaluation of Techniques to Predict Longitudinal Pilot Induced Oscillations

Author: Eileen A. Bjorkman

Publisher:

Published: 1986

Total Pages: 186

ISBN-13:

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The purpose of this study was to determine if pilot induced oscillations (PIOs) can be predicted prior to flight using existing PIO prediction techniques. Two techniques to predict longitudinal PIO tendencies (Ralph Smith's theory and Roger Hoh's bandwidth method) were studied analytically using an existing PIO data base. Suggestions were made for both techniques to allow prediction of PIO rating. The two techniques were then applied to 18 aircraft/flight control system landing configuration. The 18 configurations were flight tested using a flared landing task with the USAF/Calspan variable stability NT-33A. Smith's theory correctly prediction the PIO tendencies and frequencies provided the configuration was not sensitive to the pilot model used. A suggested modification to Smith's theory correctly predicted PIO ratings within an average of 0.6 rating. A suggested modification to Hoh's bandwidth method predicted PIO ratings within an average of 0.5 rating. The limited data base was too small to draw any definite conclusions. Recommendations for further study included collecting more PIO data and using existing data bases and simulator studies to better define the two techniques and to gain physical insights into PIO mechanization. (Theses).

Unified Pilot-Induced Oscillation Theory. Volume 1. PIO Analysis with Linear and Nonlinear Effective Vehicle Characteristics, Including Rate Limiting
Unified Pilot-Induced Oscillation Theory. Volume 1. PIO Analysis with Linear and Nonlinear Effective Vehicle Characteristics, Including Rate Limiting

Author:

Publisher:

Published: 1995

Total Pages: 300

ISBN-13:

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This work was conducted as part of a USAF initiative to develop a comprehensive theory to predict pilot-induced oscillation (PIO) tendencies due to the combined effect of all influencing elements. A PIO is a very complicated phenomenon stemming from a dynamic interaction between the pilot and the aircraft. When tight control is required from the pilot, an undesired oscillation can result. However, the adaptive nature of the human pilot makes such oscillations difficult to predict. The independent research of STI included: compilation of available PIO time histories and references as an initial step toward a comprehensive PIO database; refinement of the proposed PIO categories defined in NASA CR-4683; development of PIO theories based on these categories; development of methods to handle the higher frequency and nonlinear aspects of PIO analysis with an emphasis on rate limiting; and a review of existing and proposed linear PIO criteria.

Prediction of Pilot-Induced Oscillations (PIO) Due to Actuator Rate Limiting Using the Open-Loop Onset Point (OLOP) Criterion
Prediction of Pilot-Induced Oscillations (PIO) Due to Actuator Rate Limiting Using the Open-Loop Onset Point (OLOP) Criterion

Author: Gregory P. Gilbreath

Publisher:

Published: 2001-03-01

Total Pages: 169

ISBN-13: 9781423530572

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Rate limiting has been a causal or contributing factor for Pilot Induced Oscillations (PIO). As part of the joint Air Force Institute of Technology/Test Pilot School (AFIT/TPS) program, an examination of the Open-Loop Onset Point (OLOP) criterion, developed by DLR German Aerospace, was conducted to see if it could predict PIO due to rate limiting and to evaluate its potential as a design tool. The criterion was applied to three previous flight test programs involving rate limiting. Findings from this analysis led to the HAVE OLOP flight test which was flown on the NF-16D Variable Stability In-flight Simulator Test Aircraft (VISTA). HAVE OLOP evaluated four longitudinal configurations with rate limiting elements inside the feedback loop. OLOP was found to over-predict PIO in some cases when using maximum stick amplitude as DLR suggests. When using actual stick amplitudes, correlation between OLOP predictions and PIO ratings was good. A new metric called stick ratio was developed to help explore the full range of stick amplitudes when using OLOP. OLOP could be a useful design tool, but because of the strong influence of stick amplitude, engineering judgement would have to be exercised. Recommendations on its use as a design tool are presented.

Investigation of Pilot Induced Oscillation Tendency and Prediction Criteria Development
Investigation of Pilot Induced Oscillation Tendency and Prediction Criteria Development

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Published: 1996

Total Pages: 298

ISBN-13:

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This report documents the results of work of three Russian institutions directed towards the development of criteria for analysis and prediction of pilot-induced oscillation (PIO) tendencies. The first section of the report covers work done at the Moscow Aviation Institute to determine some of the basic influences of PIO and develop new criteria or modify existing criteria for the prediction of PIO tendencies. The second section describes work done at the Central Aerohydrodynamic Institute to investigate PIO tendencies utilizing a ground-based simulator to evaluate the effects of feel system dynamics and control sensitivities on PIO tendencies. The third section describes work done at the Gromov Flight Research Institute on the use of TU-154 in-flight simulator to evaluate and validate various criteria for the prediction of PIO tendencies in flight for Class III aircraft.

Flight Mechanics Modeling and Analysis
Flight Mechanics Modeling and Analysis

Author: Jitendra R. Raol

Publisher: CRC Press

Published: 2023-03-31

Total Pages: 567

ISBN-13: 1000834212

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Flight Mechanics Modeling and Analysis comprehensively covers flight mechanics and flight dynamics using a systems approach. This book focuses on applied mathematics and control theory in its discussion of flight mechanics to build a strong foundation for solving design and control problems in the areas of flight simulation and flight data analysis. The second edition has been expanded to include two new chapters and coverage of aeroservoelastic topics and engineering mechanics, presenting more concepts of flight control and aircraft parameter estimation. This book is intended for senior undergraduate aerospace students taking Aircraft Mechanics, Flight Dynamics & Controls, and Flight Mechanics courses. It will also be of interest to research students and R&D project-scientists of the same disciplines. Including end-of-chapter exercises and illustrative examples with a MATLAB®-based approach, this book also includes a Solutions Manual and Figure Slides for adopting instructors. Features: • Covers flight mechanics, flight simulation, flight testing, flight control, and aeroservoelasticity. • Features artificial neural network- and fuzzy logic-based aspects in modeling and analysis of flight mechanics systems: aircraft parameter estimation and reconfiguration of control. • Focuses on a systems-based approach. • Includes two new chapters, numerical simulation examples with MATLAB®-based implementations, and end-of-chapter exercises. • Includes a Solutions Manual and Figure Slides for adopting instructors.

Scientific and Technical Aerospace Reports
Scientific and Technical Aerospace Reports

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Publisher:

Published: 1995

Total Pages: 488

ISBN-13:

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Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.