Self-calibration Method Of Angular Displacement Sensor Based On Non-homogeneous Equation Error Function

Calibration is one of the important technology means to improve the precision of the sensors or measurement instruments. The calibration consists of comparison calibration and self-calibration according as whether external measuring standard is existed during the process to obtain errors of measurement. Since the comparison calibration is affected by the limitation of external measuring standard, the calibration process is usually difficult and expensive; what’s worse, it may limits the further development of precision sensors or measurement instrument. However, self-calibration that uses instrument itself as the measuring standard can effectively solve the above problems.The development of angular displacement sensor of self-calibration method consists of multi reading heads self-calibration method and single reading head self-calibration method. They have less the same calibration precision, but the former has a higher requirement on the consistency among the reading heads, which installation of the reading heads and miniaturization of the instrument are difficult. Therefore, to solve the problems of multi head reading self-calibration model, this paper presents a self-calibration method which can realize the calibration of angular displacement sensor with single reading head. It establishes the mathematical model of self-calibration with Fourier series of difference measurement value. Combined with sequential self-calibration experiments and analysis conclusions, this paper also proposes an optimization model of self-calibration which aims to improve the correction precision of the long period system error.This paper builds a self-calibration system adapting to the self-calibration model. Through self-calibration precision testing experiments, the self-calibration model is proved effectively and feasibly. Self-calibration precision of the static test can reach ?0.7?, and the dynamic testing can reach ?0.8?. According to the factors that may affect the stability of self-calibration precision, single factor experiments were designed respectively. Experiments show that: the difference approximation error, errors caused by random factors and original error of the calibrated sensor, do not significantly affect the calibration precision of self-calibration model; the stability of uniform rotation of the turntable, will significantly affect the correction precision of self-calibration model for long period system error; the stability of direct drive motor which is used to drive the turntable, calibration precision of self-calibration model is better than ?2.4?.