Independent modal space control fidelity for semiglobal changes in dynamic properties

Much research in this decade has concentrated on the application of modal space to simplify control design and system monitoring. This investigation will address the fidelity limitations of the modal filter based classical control strategies. Specifically, when the eigen-parameters shift, in concert with semi-global changes in the systems structural properties resulting in similar mode shape but dramatic shift in frequency. Expressly, this examination will concentrate on two spatially similar five bay box trusses of exactly the same geometry (connections and element lengths) and different materials (steel and plastic) and some shift in cross-sectional dimension. The limitation of these parameter shifts should present a practical bound for future application. The investigation incorporated both analytic and experimentally based models of the structural frequency response and residue matrices to analytically model the control problem. The control is investigated for the lower frequency modes due to experimental model limitations. Investigation includes single and multi-mode control.