Abstract:
This paper presents an experimental demonstration of the active control of a novel, modular sound enclosure that is built of panels which are stiffness controlled throughout the frequency range of interest. In this range, traditional passive noise enclosures are difficult to successfully implement. The design of the lightweight, stiff panels permits active control with a manageable number of actuators and sensors. The control technique is the adaptive, feedforward, filtered-x approach. Adaptive control is needed because realistic changes in the enclosure temperature and structural resonances would degrade the performance of fixed feedforward filters. The design of the enclosures makes this adaptive approach computationally feasible. Two performance criteria are evaluated: the minimization of the sum of the squares of the accelerations of the panels, and the minimization of certain supersonic wave-number components of the surface vibration field. Both approaches are straightforward for this enclosure design, where each panel behaves like a piston. [Work supported by the National Science Foundation.]