Design and analysis of a low-cost compensated POF displacement sensor for industrial applications

We present a non-contact low-cost displacement sensor based on plastic optical fiber (POF), designed for industrial applications. The proposed system is based on bifurcated fiber bundle (BFB) approach. The bundle is composed by a transmission fiber, used both to illuminate the target and collect backreflected power, and an additional receiving fiber that allows implementing target reflectivity and input power compensation. A Monte Carlo ray-tracing technique has been developed in order to evaluate system performance and tolerances to geometrical misalignments and target surface alteration. Experimental results show an accuracy of 0.04 mm on displacement readout, on the 0-1.2 mm range, assessing reflectivity compensation.