Design And Experimental Study Of Signal Processing System For Two-Dimensional Time Grating Based On Planar Standing Wave Field

With the emergence of a new round of global scientific and technological revolution,the development of high-tech plays a more important role in improving China's comprehensive national strength and promoting people's well-being.Precision displacement measurement technology,as a frontier subject closely related to all aspects of high-tech,plays an important role in promoting the development of high-tech.With the development of science and technology,the demand for precision displacement measurement technology is no longer confined to the field of one-dimensional displacement measurement.In many fields,such as precision CNC machining center,micro-electromechanical system,coordinate measuring machine,precision equipment manufacturing,robot engineering and so on,high-precision two-dimensional plane measurement is needed.At present,the most widely used two-dimensional plane measurement system mainly has three kinds: two-dimensional plane micro-displacement measurement system,two-dimensional capacitance measurement system and two-dimensional grating measurement system.However,these three measurement systems are vulnerable to environmental interference,high accuracy and low cost.As a new type of high precision displacement sensor,time grating displacement sensor has the advantages of high measurement accuracy,strong anti-interference ability and low cost.At present,the time grating displacement sensor has made great breakthroughs in the field of angular displacement and one-dimensional linear displacement measurement,but it is still in the technical blank in the field of two-dimensional plane measurement.In order to solve the technical problems in the field of two-dimensional measurement,the concept of two-dimensional time grating displacement sensor is proposed based on the time grating technology,aiming at providing a technical solution for high-precision two-dimensional measurement.This paper mainly focuses on the displacement calculation method and signal processing system of two-dimensional time grating displacement sensor.The main research contents are as follows:1)The measurement principle of two-dimensional time grating displacement sensor is studied theoretically.The construction of two-dimensional time grating planar standing wave magnetic field and the mechanism of induction signal generation are theoretically analyzed and deduced.2)According to the mathematical model characteristics of two-dimensional time-grating induction signals,the two-dimensional time grating displacement solution method is studied.The method of displacement calculation is proposed by the following four steps:(1)separation of space-time variables based on FFT;(2)separation of two-dimensional spatial variables based on angular rotation;(3)expansion and optimization of full-angle values;(4)optimization of solution range.3)The signal processing hardware circuit is designed by analyzing the characteristics of the two-dimensional time grating induction signals.The signal processing circuit was designed and Multisim simulation was carried out.The signal processing circuit board was processed based on PCB technology,and its performance was tested experimentally.The experimental results show that the designed signal processing board can meet the requirements of two-dimensional time grating signal processing.4)Using STM32F4ZGT6 microprocessor as the signal processing core,the signal acquisition scheme for synchronous acquisition of two-dimensional time grating four-channel signals and the displacement solution method based on STM32F4ZGT6 are studied,and the programming of the lower computer program is completed.5)The upper computer design based on LabVIEW is completed,and the real-time display of two-dimensional displacement values x and y is realized.The experimental data can be stored in real time to facilitate the later data analysis.6)The experimental platform was built to carry out stability and accuracy experiments.According to the experimental results,the stability of X direction is 1um and Y direction is 2um.The accuracy of the two-dimensional time grating measurement system is tested according to the following three conditions:(1)When moving only one pitch in the X direction,the original error in the X direction is-22um~28um,the original error in the Y direction is-4um~42um.(2)When only one pitch is moved in the Y direction,the original error in the X direction is-27um~10um,the original error in the Y direction is 0~38um.(3)When moving a pitch in the XY direction at the same time,the original error in the X direction is-6um~62um,the original error in the Y direction is 2um~63um.According to the experimental results,the measurement error is traced back to the source.0~38umThe research results show that the designed two-dimensional time-grating signal processing system is feasible.The stability of the system and the originalmeasurement error are within the allowable range.The research of this subject lays a foundation for the development of high-precision two-dimensional time grating displacement sensors and also greatly promoted the development of planar two-dimensional high-precision measurement.