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First Attempts to Account for Flexible Modes in ACT/FHS System Identification

Seher-Weiß, Susanne (2017) First Attempts to Account for Flexible Modes in ACT/FHS System Identification. In: Proceedings of 43rd European Rotorcraft Forum. 43rd European Rotorcraft Forum, 12.-15. Sep. 2017, Mailand, Italien.

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At the DLR Institute of Flight Systems mathematical models of the ACT/FHS (Active Control Technology/Flying Helicopter Simulator), an EC135 with a highly modified control system, are needed for control system evelopment and simulation. So far, the models that have been derived by system identification account for rotor and engine dynamics. For comfort of ride investigations, and to improve the model quality for frequencies above 20 rad/s, the influence of flexible modes also has to be modeled. For the ACT/FHS the largest effect is the influence of vertical tail bending on pitch rate. The investigation started with a single-input/single-output system for pitch rate response to collective control inputs that was extended by one structural mode for tail flexibility. As this approach was successful, next an identified 17th order model of the ACT/FHS was also extended by one flexible mode. In this model, the structural mode was still dynamically decoupled from the 17th order model and its influence on pitch rate and longitudinal and vertical acceleration was described by influence factors in the output equations. Finally, a one-way coupled hybrid model was identified that extends the influence of the structural modes to other input/output combinations. Accounting for tail flexibility in this way extended the range of validity of the identified model up to the nominal rotor speed of 41 rad/s.

Item URL in elib:https://elib.dlr.de/113107/
Document Type:Conference or Workshop Item (Speech)
Title:First Attempts to Account for Flexible Modes in ACT/FHS System Identification
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Seher-Weiß, Susanneft-hubUNSPECIFIED
Date:14 September 2017
Journal or Publication Title:Proceedings of 43rd European Rotorcraft Forum
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:No
Keywords:system identification, rotorcraft, flexible modes, structural modes
Event Title:43rd European Rotorcraft Forum
Event Location:Mailand, Italien
Event Type:international Conference
Event Dates:12.-15. Sep. 2017
Organizer:ERF International Committee
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:rotorcraft
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:24 Jan 2018 14:29
Last Modified:24 Jan 2018 14:29

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