A report describes a study of nominal-performance (H2), robust-performance (μ-synthesis), and mixed H2methods for designing fixed-order controllers applied to an active-tendon control system for suppressing seismic vibrations in a structure. The study involves an application of advances in control theory discussed in "Mixed-Norm Design of Fixed-Order Controllers" (MFS-26404), NASA Tech Briefs, Vol. 20, No. 5 (May 1996), page 91. The mathematical model of the structure in the study includes a parametric uncertainty representative of uncertainty in the frequency of each structural vibrational mode within the control bandwidth, plus an additive uncertainty to provide stability in the presence of unmodeled high-frequency modes.

This work was done by Mark S. Whorton of Marshall Space Flight Centerand Anthony J. Calise and C.-C. Hsu of the Georgia Institute of Technology. MFS-27331

NASA Tech Briefs Magazine

This article first appeared in the March, 1999 issue of NASA Tech Briefs Magazine.

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