基于误差函数相位偏移的电场式时栅角位移传感器自标定

Research on self-calibration method of electric field time-grating angular displacement sensor based on error function phase shift

比对标定对于传感器测量精度的保持和提升具有重要意义,但其易受现场环境限制,且成本昂贵。电场式时栅精度不断刷新,寻找外部参考基准也变得日益困难。针对这一难题,提出了以圆周封闭原则为基准,利用傅里叶级数的平移定律,将电场式时栅的误差序列值以2π/n角位移值进行移相,利用具有不同移相次数的误差序列值进行频谱分析,互相补偿缺失的谐波分量,最终利用各次谐波分量重构传感器误差函数的自标定方法。并据此设计、搭建了相应的自标定实验平台。实验结果表明,该自标定方法对于电场式时栅角位移传感器中所包含的周期性误差补偿效果显著。对极内,使用该自标定方法与用光栅作为参考基准所获得的标定精度基本相当,两者误差为0.05",对极内误差下降67%;整周范围内,两者误差为0.15",整周误差下降80%。该自标定方法相比于传统的比对标定法在效率、应用范围及标定成本方面均拥有显著优势。

Comparison calibration is of great significance for the maintenance and improvement of sensor measurement accuracy,but it is easy to be limited by the field environment,and the cost is expensive.The accuracy of electric grid is constantly updated,and it is increasingly difficult to find an external reference.In order to solve this problem,a self-calibration method of sensor error function was proposed based on the principle of circular closure and the translation law of Fourier series.The error sequence values of electric field time-grating were shifted by 2π/n angular displacement,error sequence values with different phase shift times were used for spectrum analysis to compensate each other for missing harmonic components,finally,the sensor error function was reconstructed using each harmonic component.Accordingly,a self-calibration application platform was designed and built.The experimental results show that the selfcalibration method is effective in compensating the periodic errors contained in the electric field time-grating angular displacement sensor.measurement period,the calibration accuracy obtained by using the selfcalibration method is similar to that obtained by using the grating as the reference,the measurement error of two different self-calibration methods is 0.05",and the measurement period error is reduced by 67%.Over the full measurement range,the measurement error of two different self-calibration methods is 0.15",and the full measurement error dropped by 80%.Compared with the conventional comparison and self-calibration method,the self-calibration method has significant advantages in efficiency,application range and calibration cost.