A general method to incorporate independent modal control to the individual blade control of rotary wings is described. Piezoelectric material may be embedded in the blade structure and conveniently shaped to generate efficient modal filters that present excellent rejection to spillover at the design condition. Closed-loop subsystems may be optimized to improve the damping characteristics of particular blade modes in the rotating frame, aiming at helicopter vibration suppression.

34th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
Department of Mechanical and Aerospace Engineering

Nitzsche, F. (1993). Modal sensors and actuators for individual blade control. In Collection of Technical Papers - AIAA/ASME Structures, Structural Dynamics and Materials Conference (pp. 3507–3515).