W. Dehmel, K. Koenig

In this paper the preparation of the numerical model of the aircraft in flight, the system analysis, and the development of Damping Augmentation Functions (DAF) are described. At the aircraft under investigation the elevator has turned out to be the most effective control surface with respect to the symmetric vibration modes. Concerning antisymmetric modes the rudder is suited best for damping augmentation, as the most critical mode is a fishtailing mode with large aft fuselage amplitudes. The shortcomings of vibration control by the ailerons are outlined. The scheme of the analog and digital processes in the DAF circuit as well as the implementation of the control law within an Electronic Flight Control System (EFCS) are shown. In flight domains with natural aeroelastic stability, an implementation of a DAF leads to a much faster decay of vibrations. Beyond the flutter boundary of the uncontrolled aircraft, the DAF leads to a stabilisation. Transients would be reduced to zero, if there were no nonlinearities. But due to the real properties of the hardware and system components, realiter stationary low level vibrations remain beyond the flutter speed. The investigations necessary for certification of a DAF on a civil aircraft are presented.

International Forum on Aeroelasticity and Structural Dynamics 1991, Aachen

Conference Paper

englisch

21,0 x 29,7 cm, 10 Seiten

DGLR-Bericht, 1991, 1991-06, International Forum on Aeroelasticity and Structural Dynamics 1991 Proceedings; S.454-463; 1991; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

NA

aeroelasticity

Bestellbar

1991