A general model-matching formulation of feedforward control systems for active noise cancellation in ducts

Active noise cancellation in ducts using multiple feedforward sensors have been investigated by many researchers. Both adaptive and non-adaptive algorithms were proposed. However, from control system viewpoint, a general control framework based on 1-D linear wave equation for a duct is still remains unexplored. In addition to the lumped parameter settings, the wave equation contains all the details of the plant behavior. This paper presents a model-matching framework using the close-form solution of the wave equation in ducts. Simple and concise results regarding stability and performance are developed. Several design ideas are also discussed.