Robust design criteria for active control of flexible systems

Abstract

A simple method to investigate robust stability criteria for flexible systems under low-order observer-based controller designs is presented. Stability is defined in the internal sense, instead of the pure input-output (I/ O) sense; that is, stability is defined in terms of the resolvent matrix of the closed-loop system instead of the transfer matrix function. This is superior to the usual robust stability analyses based on I/ O descriptions in the sense that the situation for systems simultaneously subject to spillover ( unmodelled residuals) and parametric perturbations can be treated simply