Analog velocity feedback controller for vibration suppression and sound attenuation

Abstract

In this paper, an analog velocity feedback controller is considered for active vibration suppression of a thin plate for attenuation of sound levels in the frequency range of 0-100 Hz. The active control methods can be applied to interior cavity noise reduction, as encountered for instance in automotive applications. For that purpose, a simplified experimental vibro-acoustic cabin model was built in our laboratory and developed methodologies are demonstrated on the set-up. The set-up includes a rectangular box (1 × 1 × 2 m) which is separated with a flexible thin plate (1 × 1 × 0.001 m) to obtain two enclosed cavities: the passenger compartment (PC) and the engine compartment (EC). The vibration control is applied only on the flexible plate since the walls enclosing the cavities are made of more rigid material (wood filled concrete). By employing piezoelectric patch as actuator and laser doppler vibrometer as vibration sensor, an analog proportional velocity feedback controller is designed and built experimentally for suppressing the low-frequency modes of the flexible plate. In order to attenuate only lower-frequency structural modes of the thin panel, pre-filters are also included in analog circuit. The vibration of thin plate and sound in the passenger compartment is measured for controller-inactive and active cases while disturbing the thin plate via shaker. By measuring vibration and sound response, closed and open loop experimental frequency responses are obtained and presented. The aim of this experimental study is to investigate performance of active vibration control applications on acoustic attenuation as the first step towards robust structural acoustic control. © 2011 by ASME.