The Role Of Modeling And Flight Testing In Rotorcraft Parameter Identification
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The Role Of Modeling And Flight Testing In Rotorcraft Parameter Identification
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Author : R. T. N. Chen
language : en
Publisher:
Release Date : 1986
The Role Of Modeling And Flight Testing In Rotorcraft Parameter Identification written by R. T. N. Chen and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with Helicopters categories.
The importance of recognizing that each lower-order model used for rotorcraft parameter identification has a limited range of applicability is illustrated in some detail. Examples are given to illustrate the use of conditioning the test input signals and the potential of using multi-axis test inputs to enhance the parameter identifiability. The paper discusses the benefits and limitations of using frequency sweeps as flight-test input signals for identification of frequency response for rotorcraft and for the subsequent fitting of parametric transfer-function models. This paper demonstrates the major role played by analytical modeling and the understanding of the physics involved in the rotorcraft flight dynamics, particularly understanding the limit of lower-order models, in achieving successful rotorcraft parameter identification. (Author).
Rotorcraft System Identification
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Author :
language : en
Publisher:
Release Date : 1991
Rotorcraft System Identification written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1991 with Aeronautics categories.
Identification Modeling And Characteristics Of Miniature Rotorcraft
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Author : Bernard Mettler
language : en
Publisher: Springer Science & Business Media
Release Date : 2013-03-14
Identification Modeling And Characteristics Of Miniature Rotorcraft written by Bernard Mettler and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-03-14 with Technology & Engineering categories.
Identification Modeling and Characteristics of Miniature Rotorcraft introduces an approach to developing a simple and effective linear parameterized model of vehicle dynamics using the CIFERâ identification tool created by the Army/NASA Rotorcraft Division. It also presents the first application of the advanced control system optimization tool CONDUITâ to systematically and efficiently tune control laws for a model-scale UAV helicopter against multiple and competing dynamic response criteria. Identification Modeling and Characteristics of Miniature Rotorcraft presents the detailed account of how the theory was developed, the experimentation performed, and how the results were used. This book will serve as a basic and illustrative guide for all students that are interested in developing autonomous flying helicopters.
Parameter Estimation Techniques And Applications In Aircraft Flight Testing
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Author :
language : en
Publisher:
Release Date : 1974
Parameter Estimation Techniques And Applications In Aircraft Flight Testing written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1974 with Airplanes categories.
Flight Test System Identification
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Author : Roger Larsson
language : en
Publisher: Linköping University Electronic Press
Release Date : 2019-05-15
Flight Test System Identification written by Roger Larsson and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-05-15 with Science categories.
With the demand for more advanced fighter aircraft, relying on unstable flight mechanical characteristics to gain flight performance, more focus has been put on model-based system engineering to help with the design work. The flight control system design is one important part that relies on this modeling. Therefore, it has become more important to develop flight mechanical models that are highly accurate in the whole flight envelope. For today’s modern fighter aircraft, the basic flight mechanical characteristics change between linear and nonlinear as well as stable and unstable as an effect of the desired capability of advanced maneuvering at subsonic, transonic and supersonic speeds. This thesis combines the subject of system identification, which is the art of building mathematical models of dynamical systems based on measurements, with aeronautical engineering in order to find methods for identifying flight mechanical characteristics. Here, some challenging aeronautical identification problems, estimating model parameters from flight-testing, are treated. Two aspects are considered. The first is online identification during flight-testing with the intent to aid the engineers in the analysis process when looking at the flight mechanical characteristics. This will also ensure that enough information is available in the resulting test data for post-flight analysis. Here, a frequency domain method is used. An existing method has been developed further by including an Instrumental Variable approach to take care of noisy data including atmospheric turbulence and by a sensor-fusion step to handle varying excitation during an experiment. The method treats linear systems that can be both stable and unstable working under feedback control. An experiment has been performed on a radio-controlled demonstrator aircraft. For this, multisine input signals have been designed and the results show that it is possible to perform more time-efficient flight-testing compared with standard input signals. The other aspect is post-flight identification of nonlinear characteristics. Here the properties of a parameterized observer approach, using a prediction-error method, are investigated. This approach is compared with four other methods for some test cases. It is shown that this parameterized observer approach is the most robust one with respect to noise disturbances and initial offsets. Another attractive property is that no user parameters have to be tuned by the engineers in order to get the best performance. All methods in this thesis have been validated on simulated data where the system is known, and have also been tested on real flight test data. Both of the investigated approaches show promising results.
Flight Mechanics Modeling And Analysis
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Author : Jitendra R. Raol
language : en
Publisher: CRC Press
Release Date : 2023-03-31
Flight Mechanics Modeling And Analysis written by Jitendra R. Raol and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-03-31 with Technology & Engineering categories.
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.
Identification Of Dynamic Systems
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Author : Richard E. Maine
language : en
Publisher:
Release Date : 1986
Identification Of Dynamic Systems written by Richard E. Maine and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with Aerodynamics categories.
Pt. 1 examines the practical application of parameter estimation methodology to the problem of estimating aircraft stability and control derivatives from flight test data. The primary purpose is to present a comprehensive and unified picture of the entire parameter estimation process and its integration into a flight test program. Pt. 2 covers areas such as flight path reconstruction, nonlinear model identification, optimal input design and flight test instrumentation. This approach is referred to as the Two-Step Method (TSM), also known as Estimation Before Modelling (EBM) in the literature. It will be shown that this approach has significant practical advantages over methods which no attempt is made to decompose the joint parameter-state estimation problem. The two-step method is generally applicable to flight vehicles such as fixed wing aircraft and rotorcraft which are equipped with state of the art inertial reference systems.
Identification Of Low Order Equivalent System Models From Flight Test Data
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Author : National Aeronautics and Space Adm Nasa
language : en
Publisher: Independently Published
Release Date : 2018-09-20
Identification Of Low Order Equivalent System Models From Flight Test Data written by National Aeronautics and Space Adm Nasa and has been published by Independently Published this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-09-20 with Science categories.
Identification of low order equivalent system dynamic models from flight test data was studied. Inputs were pilot control deflections, and outputs were aircraft responses, so the models characterized the total aircraft response including bare airframe and flight control system. Theoretical investigations were conducted and related to results found in the literature. Low order equivalent system modeling techniques using output error and equation error parameter estimation in the frequency domain were developed and validated on simulation data. It was found that some common difficulties encountered in identifying closed loop low order equivalent system models from flight test data could be overcome using the developed techniques. Implications for data requirements and experiment design were discussed. The developed methods were demonstrated using realistic simulation cases, then applied to closed loop flight test data from the NASA F-18 High Alpha Research Vehicle.Morelli, Eugene A.Langley Research CenterEXPERIMENT DESIGN; DYNAMIC MODELS; SYSTEM IDENTIFICATION; FLIGHT TESTS; DATA PROCESSING; FLIGHT CONTROL; DEFLECTION; AIRCRAFT PERFORMANCE; ERROR ANALYSIS; FLIGHT CHARACTERISTICS; FEEDBACK CONTROL
Flight Test Identification And Simulation Of A Uh 60a Helicopter And Slung Load
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Author :
language : en
Publisher:
Release Date : 2001
Flight Test Identification And Simulation Of A Uh 60a Helicopter And Slung Load written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
Helicopter slung-load operations are common in both military and civil contexts. Helicopters and loads are often qualified for these operations by means of flight tests, which can be expensive and time consuming. There is significant potential to reduce such costs both through revisions in flight-test methods and by using validated simulation models. To these ends, flight tests were conducted at Moffett Field to demonstrate the identification of key dynamic parameters during flight tests (aircraft stability margins and handling-qualities parameters, and load pendulum stability), and to accumulate a data base for simulation development and validation. The test aircraft was a UH-60A Black Hawk, and the primary test load was an instrumented 8- by 6- by 6-ft cargo container. Tests were focused on the lateral and longitudinal axes, which are the axes most affected by the load pendulum modes in the frequency range of interest for handling qualities; tests were conducted at airspeeds from hover to 80 knots. Using telemetered data, the dynamic parameters were evaluated in near real time after each test airspeed and before clearing the aircraft to the next test point. These computations were completed in under 1 min. A simulation model was implemented by integrating an advanced model of the UH-60A aerodynamics, dynamic equations for the two-body slung-load system, and load static aerodynamics obtained from wind-tunnel measurements. Comparisons with flight data for the helicopter alone and with a slung load showed good overall agreement for all parameters and test points; however, unmodeled secondary dynamic losses around 2 Hz were found in the helicopter model and they resulted in conservative stability margin estimates.
Piloted Parameter Identification Flight Test Maneuvers For Closed Loop Modeling Of The F 18 High Alpha Research Vehicle Harv
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Author : National Aeronautics and Space Adm Nasa
language : en
Publisher: Independently Published
Release Date : 2018-10-17
Piloted Parameter Identification Flight Test Maneuvers For Closed Loop Modeling Of The F 18 High Alpha Research Vehicle Harv written by National Aeronautics and Space Adm Nasa and has been published by Independently Published this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-10-17 with Science categories.
Flight test maneuvers are specified for the F-18 High Alpha Research Vehicle (HARV). The maneuvers were designed for closed loop parameter identification purposes, specifically for longitudinal and lateral linear model parameter estimation at 5, 20, 30, 45, and 60 degrees angle of attack, using the NASA 1A control law. Each maneuver is to be realized by the pilot applying square wave inputs to specific pilot station controls. Maneuver descriptions and complete specifications of the time/amplitude points defining each input are included, along with plots of the input time histories. Morelli, Eugene A. Langley Research Center NAS1-19000; RTOP 505-64-52-01