23rd Congress of International Council of the Aeronautical Sciences, 8-13 September, 2002, Toronto, Canada
Paper ICAS 2002-4.3.3

SMART SPRING CONCEPT FOR HELICOPTER VIBRATION AND NOISE CONTROL

D. Zimcik (1), D. G. Yong (1), V. K. Wickramasinghe (1), F. Nitzsche (2)
(1) IAR/NRC, Canada; (2) Carleton University, Ottawa, Canada

Keywords: helicopter vibration, structural dynamics, adaptive control

Significant structural vibration is a notable and undesirable characteristic in helicopter flight that leads to structural fatigue, poor ride quality for passengers and high acoustic signature for the vehicle. Previous Individual Blade Control (IBC) techniques to reduce these effects have been hindered by electromechanical limitations of piezoelectric actuators. The Smart Spring is an unique IBC approach for rotor vibration suppression that adaptively alters the "structural impedance" at the blade root. An adaptive notch Individual Blade Control algorithm to suppress the vibration in frequency domain has been developed and implemented based on a mathematical model to predict frequency response. Reference signal synthesis techniques were used to automatically track the shifts in the fundamental vibratory frequency due to variations in flight conditions. Closed-loop tests performed on the proof-of-concept hardware achieved significant vibration suppression at harmonic peaks as well as the broadband reduction in vibration. Investigation verified the capability of the Smart Spring to suppress multiple harmonic components in rotor vibration through active impedance control

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