基于改进三点测量法的圆径测量研究

三点测量圆度误差分离技术被广泛应用于工件形状的圆度误差和电机旋转的回转误差的分离算法中。而圆度误差能得以准确分离的关键在于合理配置三个位移传感器测头的安装角度，从而避免传递函数的分母为零的情况出现。然而，在具体实施过程中，位移传感器测头的角度安装误差是必然存在的，这就使得分析这一角度安装误差带来的影响变得尤为重要。基于经典的三点测量法模型，提出一种新的分析位移传感器测头的角度安装误差的模型。以三点测量法圆度测量中的圆径结果为目标，根据实际工况下的各种参数设置，定量分析了位移传感器测头的角度安装误差对最终结果的影响程度。最后，使用电容位移传感器开展工件外圆的圆径测量实验研究，确认了文中误差分析的有效性，圆径测量的重复性精度可以达到2 m以下。

Diameter measurement based on improved three-point method

The roundness error separation technique of three-point method was widely used in the separation algorithm for roundness error of part shapes and rotation error of motors. The key of accurate separation in roundness error depended on setting the angles of three displacement sensor probes logically, in order to avoid that the denominator of transfer function became zero. However, during the process of specific implementation, the angle setting error of displacement sensor probes inevitably existed, which made analyzing the influence of angle setting error become much more important. Based on the classical model of three-point method, and then a new model was presented for analyzing the angle setting error of displacement sensor probes. Taking the diameter results in measuring roundness through three-point method as the goal, according to different parameter settings in actual working situations, the error of measuring results caused by the angle setting error of displacement sensor probes was quantitatively analyzed. Lastly, using capacitive displacement sensor to carry out the research on measuring diameter of circular parts, the effectiveness of error analysis was confirmed in this article and the repeatability accuracy of measuring diameter which can be less than 2 m.