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Identification of State-Space Rotor Wake Models with Application to Coaxial Rotorcraft Flight Dynamics and Control
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Identification of State-Space Rotor Wake Models with Application to Coaxial Rotorcraft Flight Dynamics and Control. |
| 개인저자 | Hersey, Sean. |
| 단체저자명 | University of Maryland, College Park. Aerospace Engineering. |
| 발행사항 | [S.l.]: University of Maryland, College Park., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 347 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-04B. Dissertation Abstract International |
| ISBN | 9781687915603 |
| 학위논문주기 | Thesis (Ph.D.)--University of Maryland, College Park, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-04, Section: B.
Advisor: Celi, Roberto. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | Modern aerodynamic analysis tools, such as free-vortex wake models and CFD-based techniques, include fewer theoretical limitations and approximations than classical simplified schemes, and represent the state-of-the-art in rotorcraft aerodynamic modeling, including for coaxial and other advanced configurations. However, they are impractical or impossible to apply to many flight dynamics problems because they are not formulated in ordinary differential equation (ODE) form, and they are often computationally intensive. Inflow models, for any configuration type, that couple the accuracy of high-fidelity aerodynamic models with the simplicity and ODE form of dynamic inflow-type theories would be an important contribution to the field of flight dynamics and control. This dissertation presents the methodology for the extraction of linearized ODE models from computed inflow data acquired from detailed aerodynamic free-vortex wake models, using frequency domain system identification. These methods are very general and applicable to any aerodynamic model, and are first demonstrated with a free wake model in hover and forward flight, for a single main rotor, and subsequently for the prediction of induced flow off the rotor as well, at locations such as the tail or fuselage.The methods are then applied to the extraction of first order linearized ODE inflow models for a coaxial rotor in hover. Subsequent analysis concluded that free-vortex wake models show that the behavior of the inflow of a coaxial configuration may be higher-order. Also, tip-path plane motion of a coaxial rotor causes wake distortion which has an impact on the inflow behavior. Therefore, the methodology is expanded to the identification of a second order inflow representation which is shown to better capture from all of the relevant dynamics from free-vortex wake models, including wake distortion. With ODE models of inflow defined for an advanced coaxial configuration, this dissertation then presents a comparison of the fully-coupled aircraft flight dynamics, and the design of an explicit modeling-following feedback controller, with both a free-vortex wake identified model and a momentum theory based approach, concluding that accurate inflow modeling of coaxial rotor inflow is essential for investigation into the flight dynamics and control design of advanced rotor configurations. |
| 일반주제명 | Aerospace engineering. Engineering. |
| 언어 | 영어 |
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: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
