一种新型的干涉条纹软件计数方法及其实现研究  

A Novel Software Interference Fringe-Counting Method and its Realization

作　　者：陈本永[1] 吴晓维[1] 李达成[2] 

机构地区：[1]浙江理工大学测控科学与技术系,杭州310033 [2]清华大学精密仪器与机械学系,北京100084

出　　处：《传感技术学报》2004年第3期371-374,406,共5页Chinese Journal of Sensors and Actuators

基　　金：国家自然科学基金资助项目 (No .5 0 2 75 1 38) .

摘　　要：一般的光学干涉条纹计数方法都是对两路相位差为π/ 2的干涉条纹信号进行整形计数 ,此种方法简便易行 ,但是当条纹信号在半个周期内发生振荡变化时 ,容易出现对信号的变化方向产生判别错误 ,从而导致最后的计数结果出现误差。针对此种缺陷 ,本文提出了一种新型的光学干涉条纹软件计数方法 :在信号过零点附近设置一对正、负阈值 ,当正弦信号上跳过正阈值或下跳过负阈值时 ,根据此时对应的余弦信号是正还是负来判断此时被测物体的正、反向运动和进行加、减计数 ;而当正弦信号下跳过正阈值或上跳过负阈值时 ,根据判断此时正弦信号的运动方向与前次正弦信号跳过阈值时是否相同来进行加减计数。该计数方法能对干涉条纹信号的振荡变化进行准确判向 ,因此能提高计数的可靠性 ,而且具有智能性 ,适应性强。Ordinary counting interference fringes often transforms them into two interference fringe signals with a phase difference of π/2, that is a pair of sine and cosine signals. From counting the signal pairs the number of fringes can be confirmed, it is simple and widely applied in optical precision measurement. But when the fringe signal fluctuates in a half of period of the signal, the ordinary counting method sometimes produces direction-distinguishing mistakes, and then induces the result errors. To address the problem, this paper proposes a novel interference fringes counting method that uses software to distinguish the forward direction or backward direction of interference fringe and to count: a positive threshold and a negative threshold are set near the zero of interference fringe signals; when the sine signal jumps up the positive threshold or jumps down the negative threshold, we can judge the move direction of the measured object to add/subtract 1 in the counter according to the positive value or negative value of the corresponding cosine signal; when the sine signal jumps down the positive threshold or jumps up the negative threshold, we add or subtract 1 in the counter according to whether the move direction of the sine signal is the same with the previous sine signal jump-threshold direction. This counting method can accurately distinguish the direction produced by the fluctuation of interference fringes. It has the advantages of accurate counting, intelligence and reliability. We demonstrate the utility of this counting method for absolute distance measurement and experimental result with a range of 1036mm is presented.

关 键 词：干涉条纹 计数 判向 阈值 软件 

分 类 号：TP319[自动化与计算机技术—计算机软件与理论]