The Development Of Grating Ruler Calibration Device Under High And Low Temperature Environment And Research On Thermal Error Compensation Method

In order to meet the performance test requirements of complex and precise mechanism in extreme space environment,the development of a general precision mechanism comprehensive performance tester which can realize the performance test of various space mechanisms in extreme environment through module selection and assembly is of great significance for the development of ground testing technology of space mechanism in China.The comprehensive performance tester adopts grating ruler to measure the displacement parameters in the environment of high and low temperature.However,at present,the calibration of grating ruler is carried out in the environment of normal temperature at home and abroad,and there is no grating ruler calibration technology in the environment of high and low temperature.This paper mainly studies the grating ruler calibration technology in the environment of high and low temperature.The research work mainly includes the following parts:(1)Design of grating ruler calibration device in high and low temperature environment.The internal fixture structure and external mechanical structure of the high and low temperature box are designed.The servo control subsystem was designed as the driving force of the calibration device,and the measured displacement and the standard displacement were measured through the NI data acquisition system and the laser interferometer.Complete the servo motor drive,raster ruler displacement data real-time acquisition and the preparation of human-computer interaction interface.(2)Research on thermal error compensation method of grating ruler calibration device in high and low temperature environment.Firstly,the thermal error of the transmission shaft is simulated and analyzed,and the influence factors related to the thermal error of the transmission shaft are obtained.The thermal error of the transmission shaft is theoretically analyzed,and the conclusion that the thermal error of the transmission can be predicted by optimizing the layout of the temperature sensor is obtained.The thermal error of the high and low temperature calibration device was measured by a temperature sensor and a laser interferometer.Thermal error modeling was carried out by using compensation table method and SVM regression method,and parameter optimization was carried out by using improved grid search method,genetic algorithm and mutation particle swarm optimization algorithm,so as to realize real-time prediction of thermal error of transmission shaft.(3)Experimental design and uncertainty evaluation.According to JJF1059.1-2012 "evaluation and representation of measurement uncertainty",the obtained measurement data were processed to complete the evaluation of measurement uncertainty of raster ruler calibration device in high and low temperature environment.The results showed that the expanded uncertainty of calibration device for 1.32μm,has reached the requirement of the preset technical indicators,and calibration of grating feet high and low temperature environment,measured maximum absolute error of the grating ruler at 0℃ to-4.39μm,at 50℃ maximum absolute error is-4.56μm.