Research On Absolute Angular Displacement Measurement Method With Self-diagnosis Function Of Installation State

Absolute angular displacement sensor is a key functional device in high-end equipment manufacturing and other precision fields.Grating encoder is one of the most researched high precision absolute angular displacement sensors in the world.However,on the one hand,grating encoder based on grating measurement principle is difficult to make further breakthroughs in principle and manufacturing due to the limitation of optical diffraction limit and ultra-precision grating line manufacturing process.On the other hand,as one of the major manufacturers,China has been faced with foreign technology blockade,price monopoly and other "bottleneck" problems in grating and other precision sensors for a long time,which seriously restricts and affects our industrial development and national defense security.At the same time,for grating encoder,sensor installation accuracy is an important factor affecting sensor measurement accuracy.At present,some foreign companies such as Heidenhain and Renishaw which have long researched and produced grating encoders,have taken a leading position in the state diagnosis research of sensor installation,such as eccentricity and tilt.The self-diagnostic tools and technologies related to the installation and measurement of angular displacement sensors have been applied in the market.High-precision grating encoders with the function of diagnostic indication of installation status have been mass-produced.But our country has not achieved relevant achievements in this field because of the technical blockade and the late research start.The electric field time-grating angular displacement sensor studied by the author’s team gets rid of the ultra-precision manufacturing requirements of traditional grid angular displacement sensor measurement for grid line marking,and realizes high-precision angular displacement measurement by taking advantage of the advantages of more precise time scale.For the time-grating angular displacement sensor,installation eccentricity and tilt are also important factors affecting the measurement accuracy of the sensor.Therefore,in order to realize the installation state self-diagnosis function of absolute time-grid angular displacement sensor,further improve the measuring accuracy of time-grid angular displacement sensor,and provide theoretical guidance for subsequent experimental research,this paper studies the absolute angular displacement measurement method with installation state self-diagnosis function on the basis of the previous absolute time-grid angular displacement sensor.The main research contents are as follows:1)The research status of grating encoders and their installation state diagnosis methods are described,and the absolute angular displacement measurement method of time-grating angular displacement sensor with self-diagnosis function of installation state is proposed.The incremental and absolute sensing structures and the absolute positioning principle of the electric field time-grating angular displacement sensor are introduced.Based on the absolute time-grating angular displacement sensor structure,the structure model of multi-probe absolute time grid angular displacement sensor is established.Based on this structure model,the self-diagnosis method of installation eccentric or tilt state is introduced,and the principle of eliminating eccentric reading error and restraining the whole circle error of multi-probe structure is analyzed theoretically.2)The sensor error is theoretically deduced and analyzed,and the error law of the sensor in the eccentric and inclined state is clarified.The electric field simulation model of the sensor is established,and the suppression effect of the shielding ring structure on the crosstalk of the inner and outer rings is simulated and verified.The traveling wave signal of the sensor under eccentric and inclined state is simulated,and the phase information of the signal is extracted,and the difference of the sensor under eccentric and inclined state is verified.3)Relevant experiments and the upper computer measurement system are designed to verify the theoretical error analysis results of the sensor.The performance of the sensor prototype is tested and the measurement results are analyzed.The experimental results show that the measurement error accuracy of the sensor prototype can reach ±1 "after the adjustment and installation of the diagnostic instructions,which effectively improves the measurement accuracy of the sensor.