Development of a robust rotational-angle optical fiber sensor using different-material cantilevers

Abstract

A rotational-angle sensor composed of two Fiber Bragg gratings glued axially on a cylindrical cantilever beam to be bent by the resultant repulsion force of three magnets is designed and proposed for detecting the rotary random position of a rotor. By means of using three different materials on cantilever beams for checking each feature's effect on this fiber optic sensor, it has been experimentally confirmed that a nearly identical performance is achieved among them. From these experimental results, a maximum deviation of 1.3 deg is obtained and it is in good agreement with the theoretical prediction. As a whole, the cantilever design exploited in this proposed optical fiber sensor configuration is independent of the intrinsic materials used. This sensor can provide a robust kind of technique for accurately measuring the rotational angle or rotational rate of a rotor in an arbitrary rotational direction for a wide range of industrial applications.