Optoelectronic Method for Structural Health Monitoring

Abstract

Important engineering constructions require geometrical monitoring to predict their structural health during their lifetime. Monitoring by geodetic devices, vibration-based techniques, wireless networks or with GPS technology is not always optimal; sometimes it is impossible as shown in this article. A method based on geodetic measurements automation applying local optical scanners for monitoring is proposed. Its originality and contribution is based on the novel method of precise measurement of plane spatial angles. It considers robust invariant AD-conversion angle-to-code for dynamic angle, signal energetic center search method, initial reference scale adjustment, and uncertainty decrease using mediant fractions formalism for result approximation. An algorithm of electromechanic parts interaction for spatial angle encoding with beforehand set accuracy is described. It is shown that by its nature it is appropriate for practically unlimited uncertainty reduction: it is only limited by reasonable ratio ‘‘uncertainty/operation velocity’’. The operation range, accuracy, scanner operation velocity, and its adaptation to objects are determined and described. The experimental results confirm that optical device of presented passive scanning aperture overcomes all recently known compared optical devices for 3D coordinates recognition in a part of offset uncertainty. It is shown that the presented optoelectronic scanning aperture is a universal tool for various practical solutions.