Study On The Principle, Manufacturing And Calibration Technology Of Metrological Radial Grating

High-precision metrological radial grating is one of the important components of the modern photoelectric angle-measuring instruments and techniques. Based on radial grating as kernel component, the photoelectric angle-measuring sensor is to be able to convert the input mechanical value into corresponding digital value. Connecting the sensor with digital display or computer, measuring and control system can be composed, the automatic measurement, digital measurement and digital control of machines and instruments can be easily realized, the application of metrological radial grating are extended to comprehensive fields.Firstly, the development of metrological radial grating technology is introduced, the application of metrological radial grating, including the digital measurement of angle, motion comparison and torsion angle measurement of the transmission shaft, are described, the key techniques of manufacturing and calibration of metrological radial grating are described.Secondly, by using the information optics theory, Moiré equation, Moiré optical field and several typical Moiré pattern of radial grating are shown, the main problems of metrological radial grating systems are analyzed, the direction-judgment signal and the design of direction-judgment circuit is discussed, the photoelectric conversion and the temperature drift and it's compensation is deeply studied. Especially, a novel photoelectric conversion circuit, which has simple configuration and high precision and can compensate the temperature drift effectually, was put forward, the experimental results are given.Third, as an important work, the photolithographic technology of radial grating is deeply studied and summarized. In general, a Fresnel diffraction pattern in proximity photolithograph with parallel light in close distance will be produced, the grating surface may often be scraped, so the phase-shifted photolithography with strength superimposition is presented, the feasibility of the phase-shifted strength superimposition is discussed, a photo-etching system with cylindrical multi-lenses is developed, and the experimental results are given. Based on the design principle of quasi-random coding, the problem in the design of reference zero mark of incremental radial grating is analyzed, and a convenient coding design of the reference mark using computer, which can greatly reduce computation and complicacy of programming, is presented, and the experimental results are given .The emulsion for photolithograph of radial grating is discussed, the characteristic curves, optical transfer function, factors affecting resolution are analyzed, a novel method of kinetic-spinning rubberizing of emulsion for radial grating is presented, a set of equipment for imperceptible emulsion rubberizing is established, and the results of the photolithographic experiment are given On the basis of experiments, the eccentricity error, which should be controlled in the tolerance range of ±1.5m, is suggestedLastly, an integrated assessment method of the quality of measuring grating signal is presented. On the basis of synthetically assessing the quality of grating signal by method of harmonic analysis, a method using wavelet analysis for assessing the quality of grating signal is given, the experimentation of wavelet analysis is shown, the calibration method and instrument for dividing error of the metrological radial grating are discussed and researched, too. Using the high-precision photoelectric radial grating photolithographic machine QGK405 developed by Chongqing University, high-speed large-scale PLD XC4013E, SCM SST89C58 and PC , a high-accuracy, quick and real-time calibration system of radial grating dividing error is established. The functions of the system, including data collection and processing, evaluation of the radial grating dividing error, spectrum analysis and autocorrelation analysis, etc. are included.