Active noise control of a duct using robust control theory

The control of sound propagation in an air-handling duct is investigated. Employing identified discrete time models of the duct, robust linear controllers are designed using the combined pole placement/sensitivity function shaping method. The particularities of harmonic noise sources are taken into account, avoiding the classical stochastic adaptive and the reference noise based methods, in order to propose solutions easy to implement in real time applications. Extensive results have shown that this approach is a relevant candidate to the narrow band problem in active noise control.