Absolute Nanometer Time-grating Displacement Sensor Structure Design And Parameter Optimization

High-precision measurement technology is one of the key technologies affecting the development of high-end manufacturing.Its development directly determines the development process and height of the field of high-precision displacement measurement.High-precision measurement devices are used as the carrier of high-precision measurement technology and used as control precision manufacturing.The key functional components of quality and feedback position severely restrict the development of key research in fields such as celestial observation,aerospace,and laser weapon launch systems.With the continuous progress of the national manufacturing industry,the requirements for high-precision displacement measurement devices are becoming more and more stringent.Not only need to achieve nanometer-level measurement accuracy,but also require the device to have an absolute positioning function.At present,the most widely used measuring device is the absolute grating displacement encoder.After years of development,it is a very mature product.However,due to foreign technology blockade and price monopoly,the development of my country's manufacturing industry is restricted.In order to break the deadlock of being constrained by others,there is an urgent need for independent research and development of high-precision measurement technology.Therefore,the author's team proposed a method to construct a reference frame of uniform motion to establish the relationship between spatial displacement and time change,and use time measurement space to achieve high-precision and large-range measurement.Based on this principle,a cross-beam absolute nano time-grating displacement sensor was introduced early,which has the advantages of high-precision measurement function and absolute positioning function.However,the sensor has the problem of the lead between the moving ruler and the fixed ruler,which increases the difficulty of installation in practical applications and reduces its application value.In order to solve this problem,this paper proposes a new high-precision reflective absolute nanometer time-grating displacement sensor.This article will focus on the research and design of the sensor,summarized as follows:1)First,the measurement principle of the nanometer time grid displacement sensor is explained,and the reflective absolute nanometer time grid displacement sensor structure is designed.The signal reflection function is realized by adding the reflective electrode and the receiving electrode,without the need to move the lead between the fixed length,and use the difference electrode.The structure realizes the absolute position measurement,and the differential sensing structure is adopted to realize the suppression of common mode interference.2)Then the error mechanism of the three influencing parameters of reflective structure,nonlinear electric field coupling and excitation parameters is analyzed,and the electric field simulation model of reflective single-row and single-row nanometer time-grating displacement sensors is established,and these three influencing parameters are verified.The law of electric field simulation error.According to the error law,a cross-reflection structure and a time-sharing method are proposed to suppress cross-talk,and a phase-shift suppression method is proposed to suppress the spatial third and fifth harmonics.3)Finally,the experimental platform is built and tested,and the hardware circuit system,software system,sensor and measurement platform system are designed.The excitation signal is generated in time periods,the traveling wave signal is automatically picked up and processed,and the Nutt interpolation method calculates the displacement.Machine data acquisition and processing functions.The prototype of the reflective absolute nanometer time grid displacement sensor with length L=600mm and cycle number N=150was fabricated using PCB technology,and experimental tests were carried out.According to the experimental results,the cross-reflective structure,time-sharing method and phase-shifting suppression method are proposed to optimize the structure parameters.The experimental verification has been optimized to reduce the first and fourth harmonic errors and improve the measurement accuracy of the sensor.In summary,the reflective absolute nanometer time-grating displacement sensor prototype designed in this paper has achieved a measurement accuracy of ±300nm in the range of 400 mm after large-range error compensation,and can achieve absolute positioning.This research result lays a solid foundation for the future development of industrialization.