Identification and Verification of Frequency-Domain Models for XV-15 Tilt-Rotor Aircraft Dynamics PDF Download
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Author: M. B. Tischler
Publisher:
ISBN:
Category :
Languages : en
Pages : 20
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Book Description
Frequency-domain methods are used to extract the open-loop dynamics of the XV-15 tilt-rotor aircraft from flight test data for the cruise condition (V = 170 knots). The frequency responses are numerically fitted with transfer function forms to identify forms to identify equivalent model characteristics. The associated handling quality parameters meet or exceed Level II, Category A, requirements for fixed-wing military aircraft. Step response matching is used to verify the time-domain fidelity of the transfer-function models for the cruise and hover flight conditions. The transient responses of te model and aircraft are in close agreement in all cases, except for the normal acceleration response to elevator deflection in cruise. This discrepancy is probably due to the unmodeled rotor rpm dynamics identification and analysis is clearly demonstrated. Keywords: Tilt-Rotor aircraft; Parameter identification; Flight testing; Frequency-domain methods; Transfer function identification.
Author: M. B. Tischler
Publisher:
ISBN:
Category :
Languages : en
Pages : 20
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Book Description
Frequency-domain methods are used to extract the open-loop dynamics of the XV-15 tilt-rotor aircraft from flight test data for the cruise condition (V = 170 knots). The frequency responses are numerically fitted with transfer function forms to identify forms to identify equivalent model characteristics. The associated handling quality parameters meet or exceed Level II, Category A, requirements for fixed-wing military aircraft. Step response matching is used to verify the time-domain fidelity of the transfer-function models for the cruise and hover flight conditions. The transient responses of te model and aircraft are in close agreement in all cases, except for the normal acceleration response to elevator deflection in cruise. This discrepancy is probably due to the unmodeled rotor rpm dynamics identification and analysis is clearly demonstrated. Keywords: Tilt-Rotor aircraft; Parameter identification; Flight testing; Frequency-domain methods; Transfer function identification.
Author: Mark B. Tischler
Publisher:
ISBN:
Category : Helicopters
Languages : en
Pages : 200
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Book Description
Timely design and development of the next generation of tiltrotor aircraft (JVX) depend heavily on in-depth understanding of existing XV-15 dynamics and the availability of fully validated simulation models. Objects of the present study are: 1. Documentation and evaluation of XV-15 bare-airframe dynamics; 2. Comparison of aircraft and simulation responses; and Development of a validated transfer-function description of the XV-15 needed for future studies. A nonparametric frequency-response approach is used which does not depend on assumed model order or structure. Transfer-function representations are derived which fit the frequency responses in the bandwidth of greatest concern for piloted handling-qualities and control-system applications. Flight tests on the VX-15 aircraft and piloted-simulation for four flight conditions from hover to cruise were planned and executed. Improved test techniques and pilot-training procedures were devised. Analytical software tools allow the identification of high-resolution spectural responses and the derivation and validation of multi-input/multi-output transfer-function models. These techniques were applied in an extensive evaluation of the open-loop flight dynamics of the XV-15 aircraft and simulation mathematical models. Deficiencies in the mathematical models were exposed and documented.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 30
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Book Description
Models of the open-loop hover dynamics of the XV-15 Tilt-Rotor Aircraft are extracted from flight data using two approaches: frequency-domain and time-domain identification. Both approaches are reviewed and the identification results are presented and compared in detail. The extracted models compare favorably, with the differences associated mostly with the inherent weighting of each technique. Step responses are used to show that the predictive capability of the models from both techniques is excellent. Based on the results of this study, the relative strengths and weaknesses of the frequency and time-domain techniques are summarized, and a proposal for a coordinated parameter identification approach is presented. (Author).
Author: Martin D. Maisel
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 222
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Author: Mark B. Tischler
Publisher:
ISBN:
Category : Helicopters
Languages : en
Pages : 200
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Book Description
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 976
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Book Description
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.
Author: Martin D. Maisel
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 232
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Category : Shock (Mechanics)
Languages : en
Pages : 748
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Author:
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Category : Government publications
Languages : en
Pages : 866
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Author:
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ISBN:
Category : Government publications
Languages : en
Pages : 868
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