A Modal H∞ Control Methodology for Damage-Tolerant Active Control

Abstract

A novel fault-tolerant control modal methodology applied to mechanical structure vibration subject to damage is here introduced. Considering that structural damage may affect each vibration mode differently, the approach is to control the modes separately, combined with H∞ technique to achieve satisfactory global performance and robustness even when the structure suffers damage. This is achieved through an appropriate control energy distribution over modes to mitigate the damage effects. The controller is designed to minimize the modal H∞ norm of the closed-loop system. An equivalent regular H∞ system is built and solved using linear matrix inequalities approach to find the solution of the modal H∞ control problem. Then, two similar aluminum beams, one with induced damage, are used to experimentally validate the methodology for damage-tolerant active control. Results show that modal H∞ control methodology has a significant performance gain over regular H∞ technique for damage tolerance.