| RIM-FODS (reflective intensity-modulated fiber optic displacement sensor) has simple structure, low construction cost, agile design, mal-condition working characteristic and extensive application, so it plays a very important part in fiber optic sensors. But its output characteristic and measurement precision would be effected by the parameters of fiber optic sensors directly. The parameters discussed in this paper are mostly the fiber's inherence ones, such as numeric aperture(NA),the core diameter and of transmission and reception fibers, the distance between transmission fiber and reception fiber, etc. Also the external parameter just as the incident intensity, to-be-measured surface's roughness and the color were considered. In this paper, the output characteristic of RIM-FODS was researched to receive its brode range, high sensitivity and increasing its interference immunity.Firstly, the current reseach situation, the elementary operational principle and output reponse of multiple probe structure types of RIM-FODS were introduced.Secondly, the mathematical models of the basic optic fiber couple and a home-made dual concentric circles RIM-FODS were formed. Based on the mathematical models, the output characteristics of the two types of fiber sensors were to simulate.thirdly, the testing system of a dual concentric circles RIM-FODS is designed and set up.Besides, the experimental research had been to open.By means of the theoretical analysis and experimental research, the important factors of the output characteristic of RIM-FODS is found. The conclusion is helpful to the design and application of the optimality. Make use of the specific value of the two paths of output luminous flux of the fiber sensors, the effection of undulate incidence light and catoptric coefficient of measured surface would be to eliminate.Finally, the plan of safety monitoring application of optic fiber transduce in the deformation and crack of the concrect is designed. |
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