Research On Reflective Plastic Optical Fiber Micro-Displacement Detection System

Along with the development of society, ranging precise is highly demanded more and more. Among the many ranging methods, optical fiber ranging is widely used in military and civil domains for its good precision characteristics. Reflective optical fiber ranging, one of the methods in optical fiber ranging, is generally accepted as the most potential ranging method because of its small volume, easy calculation, high precision and unrelated to distance. Optical fiber ranging is an effective way to solve the on-site and safety problem when people measure the distance. The real distance can be easily and convenient gained by measuring the optical signal power and converted voltage in the optical fiber ranging.Firstly, the paper analysis and compare the former precision of reflective optical fiber ranging system, then propose the method that using plastic optical fiber to make sensor instead of quartz optical fiber, which not only lower the system cost but also expand the plastic optical fiber applied range.Secondly, the paper introduce the fundamental about reflective plastic optical fiber ranging system, the way to make plastic fiber sensor, hardware system diagram, light source circuit, plastic optical fiber transmission sensor circuit, light signal receiving and transfer circuit, weak signal detection and process circuit, and MCU control and display circuit. In order to lower the cost, the design simplified the hardware system as far as possible. In designing the photoelectric conversion module, using the input resistance infinity character in amplifier, not only achieve the current-to-voltage conversion, but also play the role of voltage follower. Meanwhile, design the subtraction circuit to eliminate the impact of the system precision which is brought by dark current in the photoelectric detector, highly improved the whole system accuracy.Thirdly, we use Protel99SE, Altium Designer 9, PSpice and matlab simulation software to simulate the system, improve the design continuously and achieve the detection accuracy about 0-1mm. Lastly, the paper discuss the improvement of the system in the next step , summarize the whole work and look forward the future in this field.