Research And Design Of Generic Interface System Of Typical Displacement Sensor

Time grating is a new type of displacement sensor, measuring space by time, with a high cost performance. To improve time grating'compatibility to traditional displacement sensor, and popularize the application of time grating as soon as possible, design electrical interface of time grating which can compatible with traditional displacement sensor is needed.Most of the traditional displacement sensors (such as grating) "measure spatial displacement with space". They have good dynamic performance. But time grating has a measurement cycle in the process of measurement, which decided by the principle of time grating measuring spatial displacement indirectly by measuring time. It makes the position feedback of time grating become discontinuous in the process of dynamic measurement.To the problems of dynamic performance shortage of time grating, and not compatible with traditional displacement sensor interface, have done the following:1. A circular position predictive measurement method was proposed, modeling the measured values of time grating with time series theory, predicting the angle value of a measurement cycle later, turning absolute discrete angle measurement value into incremental continuous pulse signal for position feedback. It makes the time grating sensor based on static measurement can be applied to the continuous feedback of the dynamic position. Error correction plan of predictive measurement is researched, using the current measured value to correct the last prediction error, which makes the prediction error never accumulated.2. Regarding the circular grating and resolver as typical displacement sensor, the TTL incremental interface of HEIDENHAIN circular grating represented by incremental position value feedback, and the resolver interface with digital converter represented by absolute position value feedback is researched. The design idea of generic interface is analyzed. And the TTL incremental interface and the resolver interface of time grating are designed.3. A synchronization data capture card is designed. It can synchronize capture the TTL incremental signal of grating, TTL incremental signal of time grating and resolver interface signal of time grating, and convenient for expanding the precision testing experiment.4. The static and dynamic measurement precision experiments for time grating with compatible interface were done. The results show that: on the condition of static measurement, the time grating with TTL incremental interface and resolver interface both have little effect to the measurement precision, and be same as the original precision of time grating. On the condition of dynamic measurement, when angle acceleration value is not more than 0.03316″/ms2 in all kinds of sports status, the dynamic measurement precision of time grating is±4″, and whether using TTL incremental interface or using resolver interface, the dynamic measurement error of time grating has similar characteristics, that is, the smaller the acceleration of NC rotary table, the error is relatively smaller; and the larger the angle acceleration, the error is relatively larger.To sum up, the research of generic interface of typical displacement sensor promoted the design of compatible interface of time grating. The problem of position feedback interface of sensor in NC system was solve, and promoting the producibility and popularity application of time grating.