Research On Absolute Type Time-grating Angular Displacement Sensor With Self-calibration Function

Machinery manufacturing industry is the most important one of three major industries,and is the foundation of the national economy,so it has direct effect on the national whole development.As an important part of information technology,sensor technology plays an indispensable role in the development of intelligentization,automation and informationization of machinery manufacturing.Some industrial workplaces generally require sensors as the position feedback units to be directly readable also with strong anti-interference ability,high data reliability,interrupt protection.This type of sensors usually provide with absolute positions.At present,the measurement of time-grating displacement sensors is mainly in the form of incremental output,and absolute measurement is still in primary development.In addition,the sensor can be affected by environmental factors,mechanical and electrical parameter changes with the lapse of time,therefore causing certain accuracy decreasement.Meanwhile with the higher and higher requirement on sensor accuracy in markets,high precision reference will become a problem in the future research and development of time-grating technology.As a result,the research on absolute angular time-grating displacement sensor with self-calibration function was carried out.Research contents and achievements presented in this paper are as follows:(1)Codes disc structure and binary channels are comprehensively analyzed by studying absolute measurement principle of encoders and resolvers.In this way,a combined measurement method is proposed,realizing absolute measurement based on characteristics of time-grating displacement sensor.(2)In accordance with methods of absolute measurement proposed in this paper,the time-grating absolute measurement method was developed by use of “coarse sensor & fine sensor” and “fine sensor & fine sensor”,whose repeat parts are a couple of primes.The absolute measurement method of “fine sensor & fine sensor” not only realizes absolute measurement function,but also reduces signal output interference between two sensors.(3)The error correction is realized by the time-grating self-calibration method based on error coordinate transformation and the reconstruction error function.In this paper,the absolute measurement method and the self-calibration method are both used in the sensor design.(4)Simulation and analysis of the sensor were carried out to verify the feasibility of the proposed methods of absolute measurement and sensor structures.The sensor model is conducted in CAD software,using CAE software to do simulation work of the sensor model to obtain the sensor output signal,and using the mathematical software to carry out component-analysis of the output signal in order to improve the sensor structure.Among then,simulations of the absolute position information acquirement and sensor output signal interference demonstrate the feasibility of the presented sensor structure in this paper.(5)In the process of optimization experiment,the author uses the gear shaper or gear hobbing process instead of wire cutting to get rotor and stator slots.The experimental result shows that the improved sensor accuracy can be increased by about 20%.(6)A prototype was manufactured and then its experiments were carried out to test the performance.According to characteristics of the sensor,the experimental platform is set up to do the experimental work.Experimental results show that,in the range from 0 deg.to 360 deg.,the absolute error is-1.46 to 0.41 arc-secs with the help of self-calibration.In this paper,based on the analysis of absolute measurement principle of encoder and resolver,an absolute measurement method was proposed by use of two sensors whose repeat parts are a couple of primes combined with the characteristics of time-grating.The research of time-grating self-calibration method was carried out based on the error of coordinate transformation.The sensor structure was designed based on the combined measurement method.Simulation experiments and the experimental study of the prototype were carried out,and the results of the study show the feasibility of the sensor structure.Therefore,the research in this paper is of great significance for the development of time-grating technology and the development of multi-function in the industrialization of time-grating displacement sensor.