Temperature Self-compensating Micro-displacement Sensing Method Based On Fiber Bragg Grating

High-end precision manufacturing equipment occupies an important position in my country’s economic manufacturing,among which high-end machine tool high-precision machining is an important manifestation of it.The micro-deformation caused by the dead weight or heat source temperature of key components such as large bases and beams of high-end machine tools will adversely affect the machining accuracy of products and even the service life of the machine tool.Therefore,accurate measurement of the micro-deformation of this structure is an important step to reduce machining errors and improve product quality.However,structural deformations of this type are often tiny,requiring high-resolution sensing techniques.In addition,this structural deformation usually has the characteristic of being distributed along its axial direction.In view of the micro-deformation characteristics of such high-end machine tools,it is an important and challenging task to develop a distributed and high-resolution micro-displacement measurement method.In recent years,with the rapid development of fiber grating sensing and measurement technology,it has been widely used in equipment monitoring and other fields due to its inherent advantages such as anti-electromagnetic interference,small size,and corrosion resistance.This topic will combine the fiber grating sensing measurement and detection technology to develop a high-resolution fiber grating micro-displacement sensor.The main work of this paper is as follows:1)A fiber grating micro-displacement sensing structure with temperature self-compensation function is studied.Based on the basic principle of fiber grating sensing measurement,the temperature self-decoupling is realized by the tilt-parallel differential structure,and the theoretical construction of the fiber sensing structure is established.The model and mathematical analysis are carried out,and the influence of different FBG sensing structure models on the sensor sensitivity is discussed;2)The packaging technology based on photo-curing 3D printing technology is proposed.For the slider design of the core component of the temperature self-compensating fiber grating micro-displacement sensor,the design of the U-shaped slider is realized by the photo-curing 3D printing technology,and the photosensitive resin is treated by ultraviolet radiation.The slider of the material is cured.Explore the influence of ultraviolet radiation on the reflection spectrum of fiber grating,and determine the preparation process of fiber grating micro-displacement sensor based on photocuring 3D printing technology;3)A test platform for the displacement characteristics and temperature characteristics of the sensor is constructed,and the temperature and displacement static calibration test and dynamic test experiment of the FBG displacement sensor are carried out.According to the experimental results,it can be seen that the sensor is within the range of 0-500μm,the sensitivity of the sensor is 1.5pm/μm;in the temperature working range of 20-50℃,the sensor has good temperature compensation performance,and its temperature sensitivity is 46.5℃/pm.Then,simulate the complex environment in which the machine tool is located,such as the environment with large temperature changes,acid/alkali/humidity and other harsh environments,and explore the influence of the environment on the reflection spectrum of the fiber grating under long-term operation.The synchronous measurement of temperature displacement and the simulation of the micro-deformation of the machine tool are studied,the application test experiment of the designed fiber grating micro-displacement sensor for temperature displacement synchronous measurement,and the displacement measurement and deformation reconstruction of the distributed fiber grating micro-displacement sensing network.Based on the above experimental research,the reliability and stability of the temperature self-compensating fiber grating micro-displacement sensor in the measurement of mechanical equipment micro-deformation sensing are verified.