基于双测头的时栅位移传感器自标定方法

摘要

To improve measurement accuracy of time-grating displacement sensor and expand its application field,a new self-calibration method for displacement sensor based on two read heads was proposed.Using space shifting property and linear property of Fourier series,the relationship of Fourier series between sensor error and different sequences of two indicating values spacing fixed-angle was established.On this basis,using relative rotation of the two read heads,the Fourier series of different sequences of two indicating values spacing fixed-angle was achieved,and error function was reconstructed.The influence of fixed-angle values on reconstruction accuracy of error function was discussed.Experiment results indicate that the self-calibration method for time grating displacement sensor proposed in this paper can effectively reduce sensor error in the range of.For the time-grating displacement sensor with 72 pole pairs,the peak-peak value of remainder error after calibration is about 2″or less.This system is easy to integrate and implement,and particularly suitable for calibrating time-grating displacement sensor under special extreme conditions.The re-sults also can be applied to other same kind sensors.%为提高时栅的测量精度，扩大其应用领域，提出了一种基于双测头的时栅位移传感器实时在线自标定方法。利用空域信号傅里叶级数的空间位移和线性性质，找出了相距一固定角的两个测量位置时栅示值之差数列的傅里叶级数与误差函数傅里叶级数间的关系；在此基础上，提出利用双测头相对回转的方法，实现了相距定角的两测量位置时栅示值之差数列的傅里叶级数的获取和误差函数的重构；分析了定角取值对误差函数重构精度的影响。试验结果表明：该方法能在误差频次高、误差成分复杂的条件下有效降低整周范围内时栅的测量误差，对72对极的时栅传感器，经自标定后剩余误差的峰－峰值小于2″，达到计量光栅精度水平，且系统极易集成，易于实现。该方法特别适合于大直径、大中空等极端特殊条件下时栅的自标定，也同样适用于其他同类型位移传感器的自标定。