Controller design for active noise cancellation headphones using experimental raw data

This work presents a practical method of designing controllers for active noise cancellation (ANC) headphones. Without attempting system identification and perturbation modeling, the headphone system is directly described by a set of frequency-response data. In frequency domain, the controller synthesis problem is formulated as a constrained optimization problem, where the H₂ performance objective is minimized with various frequency-dependent constraints. The fixed-order robust controller is thus designed to achieve maximum noise attenuation with acceptable stability margins. Further, the method is able to accurately constrain noise amplification outside control bandwidth due to waterbed effect of nonminimum phase plants. This feature is very important for the ANC design to maintain an overall quality of noise reduction.