测头读数及定位误差对三点法圆度测量精度的影响

On the Effect of Reading Errors and the Angular Misalignments of the Probes on the Accuracy for Roundness Measurement with Three-Point Method

研究三点法测量圆度时测头的读数误差及角位置误差时圆度测量精度的影响。从三点法的原理出发对测量过程进行误差分析，导出了圆度测量误差方程，并通过计算机仿真详细研究了测头的读数及角位置误差对圆度测量精度的影响。圆度测量精度主要决定于读数误差；如果3个测头间的夹角选择不当，将使测头读数误差在某些谐波上被大大放大。必须恰当选择3个测头间的夹角，使读数误差对圆度各次谐波测量结果的影响都较小。

Aiming at studying the effect of the reading error and the misalignment of the probes on the accuracy for roundness measurement with three-pointmethod, based on the principle of three-point methodand a thorough error analysis on the measurement process, the equation of roundness measurement error is derived. Also the effect of the reading errors and the angular misalignments of the probes on the accuracy forroundness and all the harmonics measurements has beenanalyzed in detail by computer simulation. The accuracyof roundness measurement is dominated by the readingerrors of the probes. If the angular positions of the threeprobes were arranged impr0perly. it might make thereading err0rs over amplified at some harmonics 0froundness. In 0rder to impr0ve the accuracy for round-ness measurement by three - point method, the anglesbetween three probes must be optimized,so that the ef-fect of the reading errors and the angular misalignmentson the accuracy for the measurements of all harmonics ofroundness could be minimized.