Spatial H∞ Approach to Damage Tolerant Active Control

Abstract

Damage tolerant active control is a new research area targeting to adapt fault tolerant control methods to mechanical structures submitted to damage. Active vibration control is a mature engineering area, using modern control methods to address structural issues that may result from excessive vibration. However, the subject of structural vibration control under damage represents a novel subject in the literature. There are some difficulties to adapt regular controller designs to active control, which may not result in good performance even for healthy structures. Fault detection and diagnosing research has conducted to development of the fault tolerant control area, whose methods are equally hard to translate to damaged structure control. Spatial active vibration control encompasses some techniques that present important features to structure control, however this is not necessarily true in the general control design area, where spatial constraints are normally not involved. We propose in this paper an investigation of these spatial techniques, applied to structural damage control. Several new strategies for vibration control are presented and analyzed, aiming to attain specific objectives in damage control of mechanical structures. Finite element models are developed for a case study structure, considering healthy and three different damage conditions, which are used to design controllers, adopting an approach based on a H_∞ spatial norm, and according to some of the proposed strategies. Discussion of the achieved results contributes to clarify the main concepts related to this new research area, and controller performance analysis permit to foresee successful real case application of the techniques here described.