Article ID: 25-00112
A new optical inclinometer is proposed in this paper. In environments such as buildings under construction, where disturbance vibrations are always present, accurate inclinometer measurements are required. The sensor consists of a light emitting diode (LED) as the light source, a ball lens on a concave lens forming the optical system, and a position-sensitive detector (PSD). Viscous fluid is used around the ball lens both to suppress minor vibrations from the installation site and to serve as an additional optical element. Ray-tracing simulation was employed to design this optical system. It was determined that the silicone oil is the most suitable viscous fluid for the optical inclinometer due to its damping of vibrations, temperature stability, and appropriate refractive index. The resolution of the inclinometer output was estimated to be 0.00052°. Disturbance vibrations with frequencies ranging from 0.1 Hz to 1.0 Hz and accelerations from 0.17 mm/s2 to 9.11 mm/s2 were applied to the inclinometer to evaluate its stability. Since the output angle during those process was at most approximately ten times the resolution, the inclinometer is considered to be minimally affected by these disturbance vibrations. The developed optical inclinometer offers high resolution for tilt sensing and robust stability against disturbance vibrations.
