Research On Multi-circle Absolute Angular Time-grating Sensor

In recent years,my country's rapid development of science and technology has put forward more requirements on sensors in the fields of precision measurement and industrial automation.Compared with incremental sensors,absolute sensors have the advantages of direct output of absolute position,no need to find absolute zero after power off and restart,and no cumulative error during use.It is widely used in robotics,CNC machine tools,aerospace and other fields.When the military and aerospace fields require sensors with high accuracy,small space,and a measurement range of more than 360°.A single-turn absolute sensor cannot meet the requirements,and a multi-turn absolute sensor is needed to replace it.My country's high-precision sensors mainly rely on imported foreign grating sensors,which are not only expensive,but also high-precision grating angular displacement sensors impose a technical blockade on my country,which seriously affects the pace of my country's realization of a manufacturing power.The time-grating displacement sensor was created by the Chinese in the world.By constructing an alternating electric field that moves at a constant speed,the precision reticle of space in the traditional measurement industry is converted to time measurement,which reduces manufacturing restrictions.Through the appraisal of the Institute of Metrology,the measurement accuracy within the range of 360° has reached ±0.06?,reaching the international leading level.In order to improve the domestic manufacturing level,this paper has developed a multi-turn absolute circular time grid sensor based on the previous research.The multi-turn absolute sensor is mainly composed of a single-turn absolute sensor and a multi-turn counting module.This paper first uses a single-row electric field circular time-grating as a prototype,and proposes a single-turn absolute circular time-grating based on re-modulation.A two-stage single-column time-grating angle displacement sensor is used to form a single-turn absolute sensor,and four orthogonal traveling wave signals are constructed through the first-level sensor,and the differential two traveling wave signals are directly reflected as the fine measurement signal;at the same time;Use the four-channel quadrature traveling wave signal of the first level as the excitation signal of the second level sensor for secondary modulation to obtain the whole cycle single period signal as the rough measurement signal.The fine measurement signal combined with the coarse measurement signal realizes the single-turn absolute type Angular displacement measurement.On this basis,combined with Wiegand multi-turn counting module to record the number of turns,so as to achieve multi-turn absolute angular displacement measurement.The mechanical tooling,hardware circuit and upper computer measurement system of the sensor were designed,and the sensor prototype was made,and the accuracy test experimental platform and application platform were built,and the sensor accuracy test and multi-turn test were carried out respectively.Accuracy test and multi-turn test are carried out on the designed sensor,and the sensor structure is optimized by analyzing the experimental error of the accuracy test.Experiments show that the original accuracy of the developed sensor reaches ±10" in the whole circle,and the number of turns can be accurately memorized under power-off and power-on conditions.In summary,the multi-turn absolute circular time-grating sensor designed in this paper has high single-turn accuracy and high multi-turn digits,and can realize passive counting,which is of great significance to the development of the domestic precision measurement field.