The Research On Reflective Intensity-modulated Fiber Displacement Sensor And Application In Digital Gauge

RIM-FODS(reflective intensity-modulated fiber displacement sensor) is one of the earliest developed fiber sensors. In this paper, five aspects - illumination specialties of optic-fiber sensor, design project of the whole system, signal manipulation circuits, experimentations to testing sensor's capacities and application in digital gauge, were deeply researched.Firstly, the characters, varieties and actualities of fiber sensors were introduced. And the meanings of researching RIM-FODS were mentioned.Secondly, the work principle of the RIM-FODS was described. The math model of light reception power of the sensor's detector was formed. Based on this math model, the illumination specialties of a fiber sensor were analyzed with the use of Matlab and Labview to build simulation system. The rules that varieties of parameters obeyed in affecting the output character were determined, which provided valuable references for fiber sensor designers. The parameters discussed in this paper are mostly the fiber's inherence ones, such as the core diameter and numeric aperture (NA) of transmit and reception fibers, etc. Also the external parameter just as the distance between transmission fiber and reception fiber was considered.Then, the design and manufacture of RIM-FODS were described in details. In this chapter, the fiber types and the detector's structures were introduced, and the suitable type was selected for the RIM-FODS designed in this paper. The voltage output model of this sensor was formed. Based on this model, the compensationstructure and compensation arithmetic were brought forward, which were used to eliminate the influence arising from lamp-house's wave, photoelectric cells' excursion, the to-be-measured surface's glisten coefficient, etc.In succession, the signal manipulation circuits were narrated. Emphases were put on the structures of light transmission machine and reception machine, the choice of photoelectric cells and the driving circuits. Several chips used in the main circuits such as the differential amplifier circuit and the AC/DC conversion circuit were introduced, and the parameters of these chips' periphery circuits are calculated. According to the centre frequency, 1KHz, the band-pass filter were designed.After the whole system having been manufactured, some experiments were done to test the sensor's capabilities. Firstly, a series of experiments were done to measure the affecting power of these factors as the to-be-measured surface's roughness, veins, shape, material, nick and lustration degree, the uprightness degree between the surface and the detector and so on. Then experiments testing the sensor's displacement distinguish rate, repetition and stability were performed, and conclusions were drawn from the tested data.Finally, the sensor's practical use in digital gauge was realized, in this part, the mechanical structure and measuring principle of this digital gauge were introduced firstly. Sensors' two different installation pattern in the gauge are described, and each infection to the measuring results was analysed. The measuring flow of this gauge, including demarcating of sensors and the measuring of standard workpiece, was listed out. Also experiments were done to test the gauge's repetition and stability. In the end, the system's uncertainty was analysed, and validated by experiments.