22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-7.2.1

ACTIVE FLUTTER SUPPRESSION FOR NONLINEAR AEROELASTIC SYSTEM

T. Degaki
Department of Aeronautics and Astronautics, University of Tokyo, Japan

Keywords: aeroservoelasticity, transonic flutter, cfd, sliding mode control

This paper describes two-dimensional active flutter suppression to cope with the transonic dip using sliding mode control. The airfoil has plunge and pitch degrees of freedom with leading and trailing edge control surfaces. The aerodynamic forces acting on the airfoil, lift and pitching moment, are calculated by solving Euler’s equations using computational fluid dynamics. At a specific altitude, flutter occurs between Mach number of 0.7 and 0.88, which corresponds to the transonic dip. Sliding mode control makes the airfoil to be stable all through the Mach number of flutter occurrence. Sliding mode controller gives wider flutter margin than linear quadratic regulator. These characteristics indicate that sliding mode control is useful for active flutter suppression in the transonic flight.

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