Most Individual Blade Control (IBC) approaches have
attempted to suppress the rotor vibration by
actively altering the varying aerodynamic loads on
the blade using techniques such as trailing-edge
servoflaps or imbedded piezoelectric fibres to twist
the blade. Unfortunately, successful implementation
of these approaches has been hindered by
electromechanical limitations of piezoelectric
actuators. The Smart Spring is an unique approach
that is designed to suppress the rotor vibration by
actively altering the structural stiffness of the
blade out of phase with the time varying aerodynamic
forces. The Smart Spring system is able to
adaptively alter the stiffness properties of the
blade while requiring only small deformations of the
actuator, which overcomes the major problems
inherent in the former approaches. The theoretical
characterisation of the Smart Spring system as a
class of active Tunable Vibration Absorbers (TVA) is
presented in the paper. A real-time adaptive control
system was developed for a Smart Spring to suppress
vibration. Initial aerodynamic wind tunnel test
results using the proof-of-concept model of the
device in a fixed blade indicate that the Smart
Spring can evolve into a powerful approach for
IBC.