Distributed parameter modal sensors

This paper deals with distributed parameter sensors designed with a view to extracting a vibration mode. Compared to conventional point type sensors such as acceleration pickups, displacement sensors etc., the distributed parameter sensors have many benefits provided that they are properly designed. First, this paper overviews a conventional modal filter designed by use of point sensors, and enumerates the problems it involves. To overcome the drawbacks of the point sensor based modal filtering, a novel modal filtering technique based upon a PVDF film sensor, a distributed parameter sensor, is proposed. Two dimensional modal filters are discussed, and then, by taking into consideration a practicability of the sensors, a design procedure of one dimensional modal filters is presented; the number, location and shaping of the one dimensional sensors are clarified. Finally, an experiment is conducted, showing the capability of the distributed parameter modal filtering.