This paper presents a novel method to identify the squareness errors of computer numerical control (CNC) machine tools based on double ball bar (DBB) measurements. A series of spherical S-shaped paths are proposed to measure the squareness errors, instead of the generally used circular detection paths since the presented method requires only one experimental setup, and three translation axes are linked, which is more convenient and comprehensive. In this article, the coordinate transformation method and the method for dividing experimental paths evenly are used to solve the asynchronization between actual motion and DBB sampling process. The experimental data is then combined with the product of exponential (POE) model to calculate the three CNC machine tool squareness errors and applied to a spherical spiral testing path with the compensation of the diagnosed errors. The effectiveness of the method is verified by comparing the experimental results before and after the compensation.

本文提出了一种基于双球棒（DBB）测量来识别计算机数控（CNC）机床垂直度误差的新方法。由于该方法只需要一个实验装置，并且连接了三个平移轴，因此提出了一系列球形S形路径来测量矩形误差，而不是通常使用的圆形检测路径，这更加方便和全面。本文采用坐标变换法和实验路径均分法解决实际运动与DBB采样过程之间的异步问题。然后，将实验数据与指数乘积（POE）模型相结合，以计算三个CNC机床矩形度误差，并在补偿了诊断出的误差的情况下将其应用于球形螺旋测试路径。通过比较补偿前后的实验结果，验证了该方法的有效性。