APPLICATION OF TWO DESIGN METHODS FOR ACTIVE FLUTTER SUPPRESSION AND WIND-TUNNEL TEST RESULTS.

The synthesis, implementation, and wind-tunnel test of two flutter-suppression control laws for an aeroelastic model equipped with a trailing-edge control surface are presented. One control law is based on the aerodynamic energy method, and the other is based on results of optimal control theory. Analytical methods used to design the control laws and evaluate their performance are described. The test objective was to demonstrate an increase in flutter dynamic pressure of at least 44 percent over a range of Mach numbers by using active flutter suppression. At Mach 0. 6, 0. 8, and 0. 9, increases in flutter dynamic pressure were obtained but the full 44-percent increase was not achieved. However, at Mach 0. 95, the 44-percent increase was achieved with both control laws. Experimental results indicate that the performance of the systems is not so effective as that predicted by analysis. Also, the results indicate that wind-tunnel turbulence plays an important role in both control-law synthesis and demonstration of system performance.