Robustness studies for H∞ feedback control in a structural acoustic model with periodic excitation

Results from an extensive study on the robustness of an H^∞ compensator for a 2-D structural acoustic model are presented. The effects of frequency uncertainties in an exogenous signal are studied for both the case where the signal is contained in the controller formulation and the case where it is excluded. Delays are inserted in the input and/or output signals and their effect on the controller performance is recorded. A comparison between the standard LQG/Kalman filter and the H^∞/Min-Max compensator reveals no significant differences in the overall controller performance. Modifications in the controller structure are studied to see whether loss of information (the tracking variable) that must be calculated a priori would result in performance degradation. This study provides valuable insight into the computational and implementational issues that arise when dealing with the control of large and complex systems that are governed by partial differential equations.