时栅角位移传感器在线自标定系统

为解决时栅角位移传感器在实际应用中的在线标定问题,提出了一种定角平移自标定方法并设计了相应的自标定系统。该方法首先把圆周封闭的自然基准转换成定角基准,在时栅内部建立了自标定基准。然后,根据傅里叶级数的性质,将定角基准平移到傅里叶变换的幅值和相位中,建立了测量值之差与误差之差的函数关系。通过对测量值之差进行傅里叶分析,重构了时栅角位移传感器的误差函数。最后,讨论了影响自标定精度的误差来源,并设计了传感器的零点纠错算法。为了检验自标定效果,利用激光干涉仪实验装置与自标定系统进行了对比试验。结果表明:定角平移自标定精度为1.9″,与理论计算的自标定误差(1.5±0.5)″的结论相符。提出的自标定方法在解决时栅自身标定基准的同时,满足了精密测量领域对时栅精度和可靠性的要求。

Online self-calibration system for time grating angular displacement sensor

To implement the in-line self-calibration of a time grating angular displacement sensor in practical applications, a self-calibration method called Fixed Angle Shift (FAS) was presented and a self-calibration system was designed. Firstly, circle-closed natural base was shifted to a fixed angle base to be as the self-calibration base of time grating. According to properties of Fourier series,the relations between differences of measured values and errors were established by shifting the fixed angle base to amplitudes and phases in the Fourier transfer. Then, the error function was reconstructed based on the Fourier analysis for differences of measured values. Finally, the error sources effect on the calibration accuracy were discussed and a zero point correction algorithm was designed. To verify the results of self-calibration, self-calibration experiments were performed and compared with the proposed FAS system and a laser interferometer. Experimental results indicate that the accuracy of self-calibration with FAS method is 1.9", which is well consistent with that of the theoretic calculation (1.5±0.5)". The method solves the self-calibration base of the time grating angular displacement sensor and satisfies, the requirements of precise measurement systems for high precise and high reliability.