A Study on the Polymer Optical Magnetic Sensor

• Main Authors: Kun-Huang Wang, 王昆煌
• Other Authors: Yung-Chuan Chen
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/66453993060719682049

碩士 === 國立屏東科技大學 === 車輛工程系所 === 101 === In this thesis, a magnetic sensor used to measure magnetic field with a flux density less than 30 G is proposed based on polymer optical fiber (POF). The effects of different design parameters on the measurement range of the magnetic field and sensitivity of the developed POF sensor are investigated. The parameters discussed are the distance between two fibers, fiber diameter, weight of iron powders and location of the sensor placed. Both experimental tests and numerical analyses which combined the finite element model and the rays’ tracing model are used in this study. The numerical solutions are used to explain the phenomena of experimental results. In this study, the magnetic material used for the POF sensor is iron powders. Three different sizes of iron powders, i.e. 0.08 um, 55 um and 200 um, are used to explore the effects of different design parameters on the measurement range of the magnetic field and sensitivity of the POF sensor. The results indicate that if iron powders have the same diameters, the distance between two fibers is the most impact factor on the measurement range of the magnetic field and the sensitivity. A shorter distance between two fibers results in a higher sensitivity for the magnetic sensor and therefore a smaller magnetic field can be measured. In addition, the sensitivity of the magnetic sensor increases with an increasing weight of iron powders and increases with a decreasing fiber diameter. The result also shows that a higher sensitivity is obtained when the angle of sensor is located at 0 degree with respect to the direction of measured field. In this study, the best sensitivity is S=0.00747 V/G. Based on the experimental results, an empirical equation is proposed to estimate the magnetic flux density for various sensor measurement angles, distances between two fiber ends, fiber diameters and weight of iron powders. A good agreement between the measured results and the results obtained from the proposed empirical equation is observed. The maximum difference is less than 8 %.