Study On Pinciples And Experiment Of Novel Light Field Type Time Grating Displacement Sensors

Precision measurement level show the national comprehensive power andtechnological level. Manufacturing technology development, military equipmentimprovement and high technology field development all rely on precision measurementlevel. Among various precision displacement measurement methods, opticalmeasurement methods has remained dominant role due to its high precision, large range,high reliability and so on. Among the optical measurement methods, laserinterferometers and optical grating sensors are applied widely. However, due to the highcost of the manufacturing equipment for traditional optical measurement sensors withhigh precision and strict limited by the abroad, our national optical precisionmeasurement technology and equipment are lag behind international advancedtechnology.Writer’s work team design displacement sensors which use time clock pulses as themeasurement reference, named as time grating. After ten years development, previousresearch on magnetic field type time grating has achieved great achievement. However,with the development of the process of industrialization, magnetic field type timegrating are easily affected by electromagnetic induction, self-inductance, mutualinductance etc., the measurement precision and dynamical characteristics are hard toimprove. All these restrictions promote time grating research changing to light fielddirection due to its some advantages.This dissertation based on the previous time grating research focus on the novellight field type time grating research, and try to build moving coordinate system forrealizing space measurement using time. In this way, the sensors’ manufacturedifficulties and cost will greatly reduce. The main research contents and innovations areas follows:①From the time-space transformation of measurement reference theory, thisdissertation illustrate the key factor for light field type time grating-how to build thelight field moving coordinate system with constant scanning speed. In addition, thisdissertation summarize systematically three constant motion, i.e. mechanical motion,configured travelling wave and natural travelling wave. Man-made constructed spacetravelling wave with field intensity periodical variation is defined as configuredtravelling wave. Contrastive analysis produce mechanisms on the natural travelling wave and configured travelling wave, characteristics and applications in displacementmeasurement.②From the light of wave-particle dualism, this paper propose innovatively thethree sensing mechanisms of the light field type time grating:1) Motor-driven scanning and timing-driven of photosensitive unit scanning modesare analyzed systematically, and realize light field type time grating sensingmechanisms in static state using light field scanning at constant speed.2) Light intensity orthogonal modulation to build moving light field scanning modewith space periodicity are analyzed systematically, and realize light field type timegrating sensing mechanisms in dynamic state using configured travelling wave scanningat constant speed.3) Using the method of circular polarization interference with low frequencydifference to synthesize rotating light field are analyzed systematically, and realizeanother light field type time grating sensing mechanisms in dynamic state using naturaltravelling wave scanning at constant speed.③Using high precision internal integrated light-sensitive array in CCD and themeasurement principles of the light field type time grating in static state, a scanningmeasurement model at constant speed for space uniform distribution CCD with timeseries stagger is proposed. The experiments are performed and the results show that themeasurement precision can reach±5" a cycle.④Two dynamic light field type time grating sensors, which are respectively alitht field coupling type time grating in dynamic state and a different frequencyinterference type time grating in dynamic state, are designed. And mainly introduces thestructure of light field coupling type time grating design, hardware design,and softwaredesign,etc.Take a light field coupling type time grating sensor for example, the first dynamiclight field type time grating linear displacement sensor is designed, and correspondingexperiment system is built for a light field coupling type time grating sensor. Thevarious influence factors on the constant speed of generated light field travelling waveare analyzed, and the results caused by influence factors are analyzed in detail.Therefore, a high precision measurement method is proposed. The measurement resultsshow that the measurement precision can reach±0.5μm within the range of54mm.In conclusion, this dissertation analyzes deeply the construction method of theconstant coordinate system for time grating sensors. The three different moving scanning models are explored, and three corresponding implement methods i.e.mechanical motion, light field configured travelling wave and natural travelling waveare proposed. And three sensing mechanisms for time grating sensors are analyzed indetail. A CCD time grating sensor and light field type coupling time grating sensor aredesigned, and many experiments are performed. This dissertation content is involved inkey project ‘Basic study on sensing measuring principles and components of nanometertime grating with large range’(Number51435002) supported by National ScienceFoundation in this year. The content is an original fundamental research, and is a newexplore procedure. However, the related references are rarely. The experiment resultsverify the scientificity and validity of the theoretical derivation. The measurementprecision of the principle prototype is almost equal to that of existing magnetic fieldtype time grating sensors. However, targets of the large measurement range andnanometer measurement precision are hard to achieve currently. But we hope to make abreakthrough to realize nanometer measurement precision.