Realization And Error Analysis Of Simultaneous Measurement Method Of Angular Position And Angular Speed For Time Grating At High Speed

Sensor technology is the source of information technology and plays an important role in measurement.With the rise of industrial automation industry and the urgent demand for high-end CNC machine tools,the demand for high-precision position sensors is increasing.At present,the high-precision position sensor in our market is basically monopolized by foreign countries,and its price is high,which has become an obstacle to the development of China's machine tool and automation industry.The research and development of domestic high-precision position sensor has become an important mission of Chinese scientists and technicians.Position measurement,as an important cornerstone in the process of mechanical manufacturing,is also an indicator to measure a country's technical level in industry and science and technology.At the same time,the typical application of high-precision position and speed measurement is direct drive motor,whose maximum speed is 1000rpm.For the application of ordinary servo motor at higher speed,high-precision speed measurement has no practical significance,only through the reducer to solve the problem of speed stability.In recent years,the application of direct drive motor is the general development trend of motor industry,only the imported angular sensor can meet its use.In view of this problem,the research group has been studying the angular position and angular speed measurement with high precision for many years.Based on the measurement principle of time grating position sensor,this paper integrates the measurement technology of angular position and angular speed,and combines FPGA technology to carry out the research of synchronous measurement of time grating angular speed at high speed(1000rpm).The main research contents are as follows:(1)Through the analysis of the working principle of time grating position sensor,based on the theory of space-time coordinate conversion,a uniform moving coordinate system is established to realize the measurement of time grating angular position.Combined with the Doppler effect of time grating traveling wave,the measurement of time grating angular speed is realized,and the synchronous measurement mode is constructed.At the same time of getting the angular position,we can get the measured value of the angular speed,so as to realize the synchronous measurement of the both.(2)The theoretical method of angular position and angular speed synchronous measurement is simulated.The simulation software embedded in FPGA is used to simulate the principle of time grating position measurement to ensure the integrity of theoretical analysis of angular position and angular speed.Based on the Doppler effect and the time-space coordinate conversion standard,a unified mathematical model of angular position and angular speed synchronous measurement is established.FPGA is used in the simulation experiment of synchronous measurement to ensure the feasibility of the theoretical method.The phase difference,period and period difference of high frequency clock pulse signal are interpolated.Finally,the angular position and angular speed are obtained by counting the pulse signal.(3)According to the theory of synchronous measurement,the sensor of angular position and angular speed synchronous measurement is designed.It mainly includes the hardware circuit design and data processing software design of the synchronous measurement sensor.The hardware circuit includes the processing of excitation signal and induction signal,the configuration of FPGA system and peripherals.The software system includes phase comparison,data processing and data storage.At last,the manufacture of the whole synchronous measurement sensor and the construction of the test system are completed.(4)Experiment and error analysis.According to the measurement requirements,a reasonable experimental platform is designed,and the angular position and angular speed are tested.The experimental results show that the angular position measurement error can reach±4",and the measurement angular speed stability can reach 1rpm(5‰)at 200rpm.At 1000 rpm,the measurement stability can reach 1.5rpm(1.5‰).Finally,the angular position error and the angular speed stability error are analyzed.