Model identification for a modal state estimator from output-only data

Abstract

Precise information of the current state of motion of a vibrating system is crucial for every effective active vibration control. Due to the limitation of the number of sensors in the final operational setup, a state estimator is needed to reconstruct the current state of vibration at important degrees of freedom from a small set of sensors. If the excitation of the structure (system input) cannot be measured directly, a sensor based estimator has to be used, which operates on response data only (system output). Core piece of this estimator is a reduced model of the vibrating system. If additionally some sensors are only capable to measure spatially distributed deflection instead of the deflection at single degrees of freedom (like piezo-electric foils), the reduced model must incorporate both those sensors as well as the important degrees of freedom as outputs. For structures which cannot be excited by a measurable excitation even in the development phase, the reduced model can still be identified by an output-only modal analysis. In this work, the identification technique is demonstrated for a curved plate submerged in water and exited by a surrounding sound field. ©2010 Society for Experimental Mechanics Inc.