Feedforward controller design using model matching techniques for active noise systems

Digital model matching techniques are applied to design digital feedforward controllers for active noise cancellation in ducts. First, active noise control system in ducts that consist of primary and secondary paths is identified using the recursive least square algorithm. The mathematics of interpolation theory called the Nevanlinna-Pick problem (NP theory) is used to solve the model-matching problem. Therefore, by applying the model-matching concept a stable controller is designed that performs well in canceling the noise. Utilizing a certain weighting function in the design process gives a better performance.