Active vibration suppression of a curved plate incorporating two piezoelectric actuators is examined. This structure was chosen as one for which it was assumed that no analytical model could be developed accurately for control design purposes; rather, the aim is to identify a multi-input/multi-output (MIMO) model using Hankel singular value decomposition (HSVD). The measurement model is fitted simultaneously across all of the transfer functions in a MIMO system; therefore, a set of poles common to all of the transfer functions is selected. Different control strategies such as single-input/single-output velocity feedback and MIMO linear quadratic Gaussian (LQG) and H∞ were designed, implemented, and tested using the model identified. The system was successful in reducing the vibration of the flexible modes of the structure. The major performance limitations were the authority of the piezoelectric actuators and the choice of actuator/sensor complement.