SELF-EXCITED VIBRATORY SYSTEM FOR A FLUTTER MECHANISM

This paper describes theory and experimental verification of a self-ex cited vibratory system which can excite lower mode of the original pas sive system of a flutter wing mechanism as a hypothetical model of ins ect wings. In order to realize a self-excitation system of natural mod e of vibration, we proposed two kinds of positive velocity feedback wi th nonlinear negative damping: Van der Pol (VDP) type and negative Cou lomb friction (NCF) type. In order to drive only the lower mode, a low pass filter and cross feedback methods were proposed. It was found th at the analytical results were in good agreement with the experimental ones, and that the NCF type can excite the limit cycle motion more ra pidly than the VDP type. Robustness of the self-excited flutter motion to the change of mass parameter was also demonstrated.