K. HENRIOULLE, Distributed actuators and sensors for active noise control, 2001

Abstract

This thesis demonstrates the potential of distributed piezoelectric foils as sensors and actuators in active noise control systems. Distributed sensors and actuators offer many advantages over conventional point sensors and actuators as they are thin, lightweight and thus are easily integrated in existing structures. As such active noise control can be applied to a specific class of structures with strict limitations on mass and volume. They measure (excite) the structure over a large area. Three different types of active panels are developed based on PVDF piezoelectric material. The first is a flat acoustic actuator, capable of producing a large sound power output at low frequencies. The second is a smart foam consisting of PVDF material integrated in a passive sound absorbing material. The third is a panel equipped with a collocated volume velocity sensor/actuator pair, controlling the low frequency sound transmission through the panel. In addition a flat electrostatic loudspeaker panel is available for testing. The active panels are used as control actuator in four applications. The first is the active control of engine noise in a car interior. A second application is the active control of sound transmission through a single and double panel partition. Simulations show how the distributed actuator interacts with the passive system to reduce the sound transmission. The best and most practical configuration is experimentally validated. A third application is the active control of sound absorption. A final achievement is the experimental validation of a system that controls the sound transmission through a single panel partition with a PVDF volume velocity sensor/actuator pair. The experiments show that an active noise control system with distributed sensors and actuators increases the acoustic comfort considerably at low frequencies.

Order Code

Code: 01D6