采用四象限探测器接收干涉条纹进行位移测量时, 干涉条纹的形状会影响各探测器之间的相位差。本文在建立干涉条纹形状与干涉夹角关系模型的基础上, 提出了应用四象限探测器识别干涉条纹形状的方法。通过干涉条纹光强面积分运算方法, 推导了干涉条纹形状参数与探测器信号相位差之间的理论公式, 并给出了相位差与干涉夹角之间的关系。利用PZT匀速驱动参考镜的方法实现了干涉条纹的动态调制, 提高了信号相位差的识别精度。通过椭圆拟合技术实现了相位差在(0, π)的高精度识别, 并结合特定的正余弦累积运算实现了(-π, π)相位差的识别, 从而完成了偏转角度方向的测量。相对传统CCD条纹形状识别方法, 该方法扩大了角度测量范围, 且更适合动态测量。与高精度自准直仪进行的比对实验表明,该方法在±300″的测量精度为3″。

When a four-quadrant detector is used to receive interference fringes to measure the displacement, the shapes of the interference fringes will affect the phase difference between the detectors. Based on the relationship model between the interference fringe shape and the interference angle, a method to recognize the shape of an interference fringe by the four-quadrant detector was presented. The theoretical formula about the shape parameters of interference fringes with the phase difference of signals obtained by the detector was deduced using the area integration of interference fringe intensity, and the relationship between phase difference and interference angle was given. The interference fringes were dynamically modulated by using a PZT to drive the reference mirror uniformly, and the recognition accuracy of phase difference of the signal was improved. As the phase difference from 0 to π was recognized in high precision through the ellipse fitting technology, and the phase difference in the range (-π, π) was recognized by combining a specific sinusoid and a cosine integral calculation, the deflection angles were measured successfully. Compared with the traditional recognition method that uses the shape of CCD stripe, this method expands the measurement range of the angle, so it is more suitable for dynamic measurement. Experiment results demonstrate that the precision of the proposed method is 3″ for the range from -300″ to 300″, and the method owns higher precision as comparing with a high-precision autocollimator.