Automated frequency domain system identification

A major difficulty in designing active controllers for structural systems is the lack of mathematical models with high enough fidelity for effective control design. In order to generate models appropriate for active control design, it is often necessary to compute models directly from test data via system identification methods. Active Control eXperts (ACX), Inc. has developed two solutions to this problem. The first consists of an interactive, menu-driven program run from the Matlab computing environment. This software package, Smart ID TM , generates state space models from transfer function data using a combination of model synthesis, non-linear curve fitting, model reduction and model augmentation techniques. The second solution, and the focus of this paper, takes the Smart ID program a step farther. For large multivariable systems, it can be tedious to construct models in the interactive fashion dictated by the structure of the Smart ID program. Furthermore, in automated system ID/control design strategies, it is vital to have a system ID program that requires no user input. ACX has developed a fully automated version of the Smart ID program. This work discusses the steering logic and functionality of the program and presents system ID results using this program on several representative systems.