The effects of weighting function errors on spatial filters for structural control. [sensors for vibration damping]

Recently there has emerged a new class of sensors, known as distributed-effect sensors, which respond to spatially distributed inputs over a significant gauge length. Examples of distributedeffect sensors include the piezoelectric laminate PVDF film, modal domain optical fiber sensors, and holographic sensors. Distributed-effect sensors can be fabricated with spatially varying sensitivity to the distributed measurand, and therefore can serve as spatial filters. Spatial filters can be configured to extract a variety of structural parameters from distributed measurements that can not be measured directly using point sensors. When the spatial sensor sensitivity realized in the fabrication of a distributed-effect sensor deviates from the desired spatial sensitivity, however, the distributed-effect sensor may no longer provide the desired measurement. In this paper, we describe the modeling of distributed-effect sensors and their integration into state-space structural models. We also consider the effect of fabrication errors on the operating characteristics of the sensor. This analysis identifies limitations imposed by the sensor fabrication process on control system design.