Aeroservoelastic analysis, design and wind tunnel testing of a three degree-of-freedom binary flutter model
Date
2012-02-01
Authors
Sutherland, Alan Neville
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Abstract
Aeroelastic problems are typically limiting factors in the performance and flight envelopes of
aircraft. Aeroelastic constraints can be relaxed through active control of the flutter modes at and
above the uncontrolled flutter speed of aircraft using primary flight control surfaces. To
demonstrate the concept and associated benefits of aeroservoelasticity, a low speed, three
degree-of-freedom binary flutter model incorporating a full-span trailing edge control surface was
designed, modelled mathematically and wind tunnel tested. Open-loop flutter test results agreed
well with predictions from classical flutter theory, and gentle low speed flutter was demonstrated.
Closed-loop wind tunnel testing using a linear quadratic Gaussian controller proved that flutter
could be suppressed successfully, allowing the flutter boundary of the model to be increased
significantly. Flutter suppression was demonstrated up to a speed 54m/s, an increase of 116%
over the model’s open-loop flutter speed of 25m/s, using a controller optimised for an airspeed of
25m/s.