Development of a fiber optic sensor for triaxial displacement measurement

In designing motion-sensing systems, researchers have generally worked on measurements based on mechanical principles or the electromagnetic induction principle. However, the sensitivity can be extremely low when it is necessary to measure displacement at the micrometer scale. In addition, to read the detected movements, it is necessary to go to the measurement area and manually detect the movement with distance meters such as meters, caliper, and micrometer. However, it is advantageous to detect the movement of displacement with instant measurements in many vital areas and make sense of the obtained data by quickly transferring it to the digital environment. For this reason, researchers have also studied electrical solutions for displacement measurement. However, these structures are sensitive to electromagnetic interference. Fiber optic technology, frequently used for communication in literature and practice, has also found an effective field of activity in designing sensor structures in recent years. Fiber optic sensors provide greater sensitivity than conventional methods. At the same time, their adaptability to existing systems is relatively high in terms of their structural features. Because fiber optic sensors are electrically and magnetically insulating devices, they can be used in high voltage, high temperature, or corrosive environments. Besides these features, fiber optic sensors are compatible with communication systems and can perform remote sensing. In this study, a simple-designed, low-cost, high-precision fiber optic three-dimensional motion detector, which can detect and report the movements in the x-y-z axes online, was designed, developed, and realized. The communication between the light source and the detector is provided with the help of plastic optical fiber couplers placed on all three axes of the designed and manufactured three-dimensional movement mechanism. The proposed sensor system is based on the analysis of changes in light amplitude due to the reflection principle. Thus, the magnitude and direction of the displacement could be determined with the developed sensor. This data has been transformed into meaningful information with the circuit designed with a microprocessor and appropriate software, and it has been transferred to the computer screen instantly, allowing online monitoring. As a result of repeated measurements, the sensor assembly could accurately detect the occurrence of motion and the direction of motion in three dimensions.