Triaxial Accelerometer Based on a Semicircular Hetero-Core Fiber-Optic Sensor

In this article, we present the characteristics and performance of a cost-effective triaxial accelerometer using three semicircular hetero-core optical fibers, causing optical loss due to mechanical deformation with low transverse sensitivity. In addition to the low transverse sensitivity, calibration with a sensitivity matrix accounting for the residual transverse sensitivity compensation further improved the error of the triaxial accelerometer from 20.2% to 6.97% equivalent to commercial accelerometers. The characteristic quality parameters of the proposed accelerometer include sensitivity in the primary axis, measurement range, bandwidth, and discrimination threshold, which were 5.82
$\pm \,\,1.35\times 10^{-3}$
dB/g, ±74 g, 10–90 Hz, and
$3.56\times 10^{-2}$
g, respectively. The maximum phase difference was -12.8° due to the viscoelastic property of the ultraviolet (UV)-curable resin fiber coating. The corrected accelerations using the
$3\times $
3 sensitivity matrix were evaluated under the condition that the triaxial accelerometer was tilted to change the acceleration applied to each axis. We have successfully demonstrated the practical triaxial accelerometer using semicircular optical fiber sensors for early fault detection of industrial machinery.