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Comparing explicit and implicit modeling of rotor flapping dynamics for the EC 135

Seher-Weiß, Susanne and Grünhagen, W. von (2014) Comparing explicit and implicit modeling of rotor flapping dynamics for the EC 135. CEAS Aeronautical Journal, 5 (3), pp. 319-332. Springer. DOI: 10.1007/s13272-014-0109-0 ISBN ISSN 1869-5582 ISSN 1869-5590

Full text not available from this repository.

Official URL: http://link.springer.com/article/10.1007/s13272-014-0109-0

Abstract

To be valid up to higher frequencies, state space models derived by system identification methods have to include rotor states describing the dynamics of flapping and sometimes even downwash and regressive lag motion. In the case of flapping, the rigid body equations are usually augmented by the explicit differential equations for the longitudinal and lateral flapping angles which are then coupled to the rigid body equations through the corresponding force and moment terms. Alternatively, an implicit formulation can be used that includes the pitch and roll acceleration as model states. The paper compares the two modeling approaches for the EC 135 helicopter. For this helicopter, the formulation with flapping angles in its classical hybrid form shows some higher order deficiency in the match of the longitudinal and lateral accelerations, which are not apparent in the implicit model. After ruling out other effects, the discrepancies can be attributed to a vertical offset of the center of gravity from its assumed position. Once this offset is accounted for in the data, results from the two modeling approaches can be compared to each other and to theoretical predictions.

Item URL in elib:https://elib.dlr.de/89039/
Document Type:Article
Title:Comparing explicit and implicit modeling of rotor flapping dynamics for the EC 135
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Seher-Weiß, SusanneFT-HUBUNSPECIFIED
Grünhagen, W. vonFT-HUBUNSPECIFIED
Date:7 May 2014
Journal or Publication Title:CEAS Aeronautical Journal
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:No
Volume:5
DOI :10.1007/s13272-014-0109-0
Page Range:pp. 319-332
Publisher:Springer
ISSN:1869-5590
ISBN:ISSN 1869-5582
Status:Published
Keywords:System identification � Rotor flapping � Rotor dynamics � Modeling
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Rotorcraft (old)
DLR - Research area:Aeronautics
DLR - Program:L RR - Rotorcraft Research
DLR - Research theme (Project):L - The Smart Rotorcraft (old)
Location: Braunschweig
Institutes and Institutions:Institute of Flight Systems > Rotorcraft
Deposited By: Seher-Weiß, Susanne
Deposited On:07 Oct 2014 16:08
Last Modified:29 Jun 2015 03:04

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