Robust Estimation for Automatic Controller Tuning with Application to Active Noise Control

In this work, we show how the double-Youla parameterization can be used to recast the robust tuning of a feedback controller as a robust estimation problem. The formulation as an estimation problem allows tuning of the controller in realtime on the basis of closed loop data. Furthermore, robust estimation is obtained by constraining the parameter estimates so that feedback stability will be maintained during controller tuning in the presence of plant uncertainty. The combination of real-time tuning and guaranteed stability robustness opens the possibility to perform Robust Estimation for Automatic Controller Tuning (REACT) to slowly varying disturbance spectra. The procedure is illustrated via the application of narrow-band disturbance rejection in the active noise control of cooling fans.