System identification with reaction-mass devices

Reaction-mass devices are to be used in a dual role: first for the purpose of system identification, and second for the purpose of vibration suppression. Unlike ground-based shakers, reaction-mass devices have a position constraint which must be maintained. A two-part system identification procedure is described which maintains this constraint. In the first part, a new algorithm is used to obtain the impulse response from input-output data. The second part uses the eigensystem realization algorithm to determine linear matrix models of the structure and of the reaction-mass device. This procedure is demonstrated on a small experimental structure. The usefulness of the model for the design of a vibration suppression controller is also demonstrated.