Active reduction of device multi-tonal noise by controlling vibration of multiple walls of the device casing

The aim of this paper is to verify the idea of active reduction of device and machinery noise by controlling the vibration of their casing. The Active Structural Acoustic Control (ASAC) technology known from the literature for reducing noise propagating through a single wall is going to be applied to multiple walls of the casing, thus globally protecting the user and environment from excessive noise generated by the machine or the device. Based on previous research by the authors, pairs of vibration actuators and sensors are installed on the walls in order to provide highest sound insulation efficiency. Two adaptive control strategies are investigated - feedfoward and Internal Model Control feedback, both with the adaptive Leaky Normalised Filtered-x Least Mean Square (FxLMS) algorithm used to update control filter parameters. The control systems are experimentally verified by using a laboratory set-up, in presence of a multi-tonal primary disturbance. Obtained results are reported, discussed, and conclusions for future research are drawn.