The Research On Cylindricity Measurement Based On Reflective Fiber-optic Sensors

The thesis put forward a cylindrical error measurement method based on reflective fiber-optical sensors, according to the basic working principle of reflective intensity-modulated fiber-optic displacement sensors, combining with the measurement requirements of modern industry. This is a fast and non-contact measurement method, which has a certain application value in industrial test filed.First, a brief introduction to the reflective intensity-modulated fiber-optic displacement sensor is given. And the intensity distribution of transmitted beam of transmitting fiber is discussed. On the basis of uniform distribution, the mathematical model of reflective fiber-optical sensors for cylindrical error measurement is established, and the principle of cylindrical error measurement is determined.Secondly, a system model for cylindricity measurement is built, including illumination system, fiber-optic probe and photodetector. After analyzed the performance of an incandescent light source, a laser light source and the LED light source, the LED is used as the sensor’s light source; analyzed the progress of optical fiber probe design, and analyzed the fiber parameters that effected performances of sensors by MATLAB simulation, finally, the fiber-optic probe in the paper has coaxial structure, and its transmitting fiber and receiving fiber are 480/500μm plastic multimode fiber with a numerical value aperture of 0.5; After analyzed the performance of the photovoltaic cells, photodiodes and the photomultiplier tube, the Newport 842-PE optical power meter with a 818-SL/DB Si photodiode probe is chosen as the photodetector.At last, an experimental platform is built for the cylindrical error measurement of a hard aluminum cylindrical workpiece with a Φ40mm hole. By building an objective function according to the minimum zone method, using a MATLAB method as the optimization algorithm, the cylindrical error is obtained. To verify the accuracy, the measurement result is compared with the ZEISS coordinate measuring machine measurements, and the difference is 1.1 μm. Finally, the measurement range and error sources of the measurement method used in the paper are analyzed, and the result shows this measurement method has a measurement range of[20μm,350μm].In this paper, the research is trail and exploration on cylindrical error measurement method based on reflective fiber-optical sensors. It completes the measurement of cylindrical error, and the results prove that using reflective fiber-optical sensors to measure cylindrical error has certain feasibility.