Rack Displacement Detection Method And Technology Study Based On Embedded Time-grating Technology

With the development of aerospace,shipbuilding,metallurgy,mining,power generation equipment and other industries,and with the innovation of industrial technology,the high machining precision and transmission precision of heavy-duty machine tools as tools are becoming more and more demanded.Because of the requirement of heavy load and space position,gear-rack drive is often used instead of ball screw drive in heavy machine tools and super long machine tools.The displacement detection of rack as a final drive part is an important link to realize full closed loop control.Generally,the displacement measurement of rack is realized by install external sensors such as grating,magnetic grid and so on.However,because of the overlength driving medium,poor working environment and limited work space,the installation convenience of the sensor is restricted,and it is hard to achieve high precision displacement measurement.Aiming at the above problems,a rack displacement detection method is proposed based on time grating sensing principle.Namely,the equal mechanical division rack is used as sensor components,the time grating sensor probe embedded(or closed)in the mechanical system,the two groups are organically composed of a set of displacement detection unit.The volume of sensor head designed by this method is small,so it is easy to assemble with the rack in the mechanical system.At the same time,this sensor designed by this method inherits the advantages of strong adaptability,good precision performance and high performance price ratio of the time gate sensor.The main contents of this paper are as follows:(1)A rack displacement detection method based on embedded time grating technology is proposed on the basis of researching the sensing mechanism of the time grating displacement sensor and the transformer model.And the signal generation mechanism of displacement detection unit is analyzed.(2)The physical model of the rack displacement detection unit is designed on the foundation of studying the mechanism of sensor signal generation.The electromagnetic field simulation of the rack displacement detection unit is carried out by ANSOFT MAXWELL,and the physical model is optimized according to the simulation results.(3)The electrical system is designed according to the measurement principle of the rack displacement detection unit and the characteristics of the output signal.(4)The prototype is made,and the experiment platform is built.The principle verification experiment and the performance test experiment are carried out,according to the accuracy experiment,the peak error of the original error is about 108?m and the error of the experimental results is analyzed by FFT.In summary,a method of measuring the rack displacement is presented and the model structure of the rack displacement detection unit is designed by studying the principle of time grating sensing.The simulation analysis and structure optimization of the model structure are carried out through the simulation software,and the experimental research is carried out.Through the analysis of the experimental data,the main error source of the rack displacement detection unit is clarified.