Research On Turntable Calibration Equipment

Turntable calibration equipment is a kind of standard test platform used formeasurement. It’s main function is to calibrate and measure the performance testproject of turntable’s angular position, angular rate, error of rotation angle and so on,so as to evaluate the turntable’s property to improve instrumental precision. Atpresent, in the field of aerospace, high-precision inertia test turntable has beenwidely used in spacecraft flying simulated experiment and dynamic characteristiccalibration of the inertial device. The property may directly determine the result offlying simulator. However, the test efficiency and accuracy of the presenthigh-precision turntable calibration equipment is relatively low, which can’t meet theneed of aeronautical model research gradually. Therefore, the research of theturntable calibration equipment has important theory and scientific value.This dissertation uses large-scale, high-frequency response and high-precisiondigital grating measuring theory to research the high-precision turntable calibration.Firstly, it analyzes the index error of grating measuring system and the reading errorcaused by the installing eccentric error, explores the feasibility of using diameterindication method to eliminate the error, and increases the measuring precisioneffectively. Secondly it discusses Moiré fringe subdivision and sine and cosinesubdivision technology in detail, and carries on data collection for the original signalcaused by the raster. It provides the theoretical basis for the follow-up study of theproject.A program including four sub-systems is proposed to simplify the process of theTurntable calibration, the sub-systems are digital grating measurement system,high-precision angular position detection system, the degree of inclination of theaxis of rotation and vertical error detection system, radial rotation error detectionsystem respectively, and the sub-systems together with the precision tooling andsub-metering devices dorm a large speed range, high frequency response turntablecalibration equipment design. An practical turntable calibration equipment isdesigned by using the high performance, high flexibility of FPGA, precision clock,FIFO and DMA technique. The circuit module is developed and software is writtento translate the signal from the grating, sensor to the computer via the A/Dconversion card. The real time precise data detect is achieved and the turntableplatform’s angular rate is detected and analyzed, and achieve the calibration of theturntable platform.Finally, we propose the research of turntable precision methods and technology, build the mathematical model of the turntable precision system, evaluate theuncertainty according to the measured data, and test the precision of the turntablecalibration system. The experiments show that the data obtained from thesoft-hardware subdivision system verges to consistent compared to the theory designanticipation. The turntable calibration device precision meets the need of turntablecalibration and magnitude transmission. It has the great theory significance andpractical value in the field of scientific research and production.