2 DOF Adaptive Control of Sound Transmission through Thin Plate

Abstract

This paper describes sound transmission reduction control through thin plate by using piezoelectric ceramic sensors and actuators, both of which are bonded on both surfaces of the plate. 2-DOF control system is introduced to reject the effect of bending vibration of the periodic component and continuously distributed component over the broad frequency range. The adaptive feedforward control is realized by using FIR filters and LMS system identification algorithm. The filtered epsilon with delay system is applied to cope with the non-minimum phase of the identified feedforward control systems. The internal model control is introduced to the feedback control system, which are constructed basically with the direct velocity feedback (DVFB) system. The internal model control was efficient to suppress the howling instability to occur frequently in case of high feedback gain. The substantial reduction of the sound radiation from the plate in the control experiment proves the effectiveness of the 2 DOF control system.