Study of Mixed-Norm Controllers for Suppressing Vibrations

A report describes a study of nominal-performance (H2), robust-performance (μ-synthesis), and mixed H2/μ methods 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.