An industrial ANC application for an enclosure

An unusual ANC approach using structural sensors and actuators is investigated for its effectiveness in actively attenuating the sound radiation from an irregular enclosure excited by an internal sound field. The intention of the control strategy is to control the enclosure vibrations in such a way that the radiated sound field is minimized. For the case considered here the interior noise spectrum has most of its energy below the first enclosure structural resonance frequency, thus complicating the control design. Here the design of a suitable control system for this problem is described. This is followed by a discussion concerning the type and reliability of the equipment which is most appropriate, after which experimental results illustrating the performance of this approach are presented. The experimental data show a direct correlation between the reduction in enclosure surface vibration and the reduction in noise radiation.