Structure shape measurement method based on an optical fiber shape sensor

Abstract

In industry and architecture, real-time and complete measurement of structures has become a research frontier since it is directly related to the safety of life and property. Optical fibers have the potential to monitor constructions due to advantages such as small size, anti-electromagnetic interference, etc. However, existing research on optical fiber sensors pays attention to the sensing fiber itself and ignores the layout of the optical fibers. As a result, currently available fiber sensors are only suitable for monitoring one-dimensional rigid structures such as surgical robots and puncture needles. They may face challenges when measuring the freeform surfaces encountered in industrial and architectural scenarios. In this paper, a cross-orthogonal measurement method based on optical fiber shape sensors is proposed to meet the shape measurement requirements of freeform surfaces. The cross-orthogonal network allows global measurement and performs surface reconstructions more easily as compared to single-fiber arrays. It also divides the sensing fiber into several segments that are reconstructed separately (with different initial frames), avoiding the cumulative error at the end of the sensing fiber. Results of verification experiments using four-core fibers indicate that the presented method can improve measurement accuracy.