新型“标记法”测量大直径的计算方法

Algorithm analysis of a new "marking method" for large diameter measure ment

大直径工件的高精度在线测量技术是当今国内外尚未圆满解决的难题.基于"标记法"测量原理的大直径测量,精度可以达到IT7级.针对大直径测量对精度要求的逐渐提高,提出了一种新的方法.以完整圆测量滚轮代替了"标记法"中的不完整圆滚轮,同时采用滚轮脱离工件的后退方案,可实现在线测量.通过计算方法分析和比较,选取了切比雪夫逼近数值处理方法,在实际应用中取得了很好的逼近效果.该方法消除了测量轮为不完整圆所带来的不确定性误差,从而有效地提高了系统测量精度.实际测试证明,精度达到了国家标准IT6级.

The technology to precisely measure a large diameter work piece on-line still presents a difficult challenge. Based on marking method technology, the precision can attain IT7 level. To increase accuracy, a new method was put forward. The unintact cycle in the marking method was replaced by the intact cycle, and the datum dimension precision back method was put forward for measuring on-line. Through numerical value analysis and comparison, a Chebyshev's polynomial that can be used in practice was obtained. Because the method eliminates the indetermination error when the measuring round is not a complete circle, the precision of the system is effectively increased. It is certified that the measure precision is IT6 level of state standard in a real test.