Design And Research Of A Kind Of Wide Range And High Precision FBG Displacement Sensor

In recent years, FBG sensing technology has become one of the research hotspots in sensor area. Its theoretical foundation and practical technology have obtained rapid development. The fiber grating has many advantages, such as small volume, light weight, anti-electromagnetism interference, corrosion resistance, high sensitivity, easy to networking, etc. So it has a wide application in many engineering field.Currently, FBG displacement sensor is an important supplement of the electricity and machinery displacement sensor, and is widely used in many fields, especially in some strong electromagnetic, high radiation and strong corrosive fields. At present, there are many kinds of FBG displacement sensors that have been reported, and some of them have been used in industrial field. But these reported FBG displacement sensors is only used in short range. This is a bottleneck problem of the FBG displacement sensors.This paper uses the FBG as the sensitive components, proposes and develops a kind of FBG displacement sensor of wide range and high precision. Compared with the reported FBG displacement sensors, this proposed sensor has much wider range, simple structure, smart design. It can meet the demand of wide range and precision.This thesis includes four chapters as following:In chapter 1 the status quo and development trend of fiber sensing technology is generally introduced, including fiber grating sensing technique, the status quo of fiber sensing, different structures of domestic and foreign FBG displacement sensors.In chapter 2 the fundamental theory of fiber Bragg grating are studied using the coupled-mode theory. The basic principle of fiber grating sensing technique and several common demodulation methods in writing FBG are studied.In chapter 3 the fundamental theory of FBG displacement sensor is studied. Based on this theory, a designing scheme combined the cantilever beam and planet gear train is proposed. And its working principle is theoretical researched.In chapter 4 the proposed displacement sensor is experimentally researched, and the result shows that the range of the sensor can reach 150mm and the precision is 14 pm/mm.