A flight testing and system identification program was conducted on the SH-2G helicopter to support the development of a new digital flight control system and piloted simulation. Higher-order state-space models, which include the coupled rotor/fuselage/engine/inflow dynamics, were determined using CIFER (Comprehensive Identification from Frequency Responses) at three airspeeds that span the flight envelope: hover, 60 knots, and 100 knots. This paper discusses the flight testing techniques, the development of a physics-based identification model structure, and identification techniques that are suitable across the flight envelope. The frequency-domain system identification methods commonly used on conventional helicopters are seen to be well suited to flap-controlled rotor configurations. While key SH-2G response characteristics are not well modeled by existing analytical simulations, the flight-identified models for the SH-2G closely match the frequency response flight test database and accurately predict the lime-domain response to control doublet inputs. The identified models are characterized by highly coupled fuselage-rotor dynamics, a high degree of pitch-roll inter-axis control coupling, and important effects of engine dynamics. The identified derivatives vary smoothly with airspeed and are consistent with theoretical predictions for standard hinge-offset rotors.
Flight test identification of SH-2G flapped-rotor helicopter flight mechanics models
Flugtest zur Identifikation eines flugmechanischen Modells für die Flugregelung des Hubschraubers SH-2G durch Steuerklappen an den Rotorblättern
Journal of the American Helicopter Society ; 47 , 1 ; 18-32
2002
15 Seiten, 9 Bilder, 5 Tabellen, 30 Quellen
Article (Journal)
English
Flight Test Identification of SH-2G Flapped-Rotor Helicopter Flight Mechanics Models
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