Error sensing strategies for adaptive acoustic structures

Adaptive acoustic structure (AAS) is a special example of a smart structure applied to noise control, which makes it possible to employ active structural acoustic control as a practical control technique because of its easy-to-installation and versatile. Error sensing strategy is a key step in implementing an AAS. However, in practice only nearfield pressure sensing can be obtained, which results in degradation of noise reduction. Based on nearfield pressure error sensing strategies for AAS are investigated theoretically. Thus, if the measuring plane, which has the same area and is parallel to the vibrating structure surface, is much less than the acoustic wavelength, considerable noise reduction can be obtained by using squared pressures on the measuring plane as the cost function for AAS.