High-sensitivity weighing sensor based on broadband optical coherence displacement measurement of a dual-beam elastic element

Abstract

A novel weight sensor based on the Michelson interferometer is proposed in this study to meet the demands of complex environments. The sensor uses a dual-beam type elastic element, optimized to enhance its sensitivity. Its deformation under load is sensed by a broadband optical coherence displacement measurement system, which, in combination with the spectrum correction method, enables displacement sensing down to sub-nanometer resolution. An optical interferometric weight sensor with a rated load of 6 kg is fabricated under laboratory conditions, and its performance is verified experimentally. The proposed weight sensor demonstrates good stability and achieves a sensitivity of 146.814 μm/kg, theoretical resolution of 0.004 g, nonlinearity error of 0.034%, maximum repeatability error of 0.036%, and maximum hysteresis error of 0.055%, with the relative error of the identification threshold not exceeding 0.1%. The proposed weighing method and sensor represent a significant improvement over other reported interferometer-type weight sensors.