We propose a technique to measure position-independent geometric errors (PIGEs) in the rotary and spindle axes of a hybrid parallel kinematic machine (PKM). The PKM investigated here includes one more rotary axis than an Exechon PKM, which is used to improve the productivity of hybrid processes, such as machining and direct-energy-deposition three-dimensional metal printing. Errors in the measured position and orientation of the rotary axis, and the orientation of the spindle axis produce volumetric errors in the processed workpiece. If accuracy is to be improved, the deviation of each axis must be measured and compensated. In our approach, errors are measured using three methodologies that require only control of the rotary axis: in the first, no offset is applied to account for positional deviation of the rotary axis; in the second, an offset is used to correct the orientation of the rotary axis; and in the third, a tool offset is used to correct the orientation of the spindle axis. We developed an algorithm that uses the three measured datasets to identify PIGEs. The proposed method was applied to a hybrid PKM and the PIGEs were measured and compensated. This technique uses simple measurement paths and sequential measurements to correct rotary and spindle axis errors, and could therefore be widely used in industry.

我们提出一种技术来测量混合并联运动机（PKM）的旋转轴和主轴上与位置无关的几何误差（PIGE）。与Exechon PKM相比，此处研究的PKM包括更多的旋转轴，该轴用于提高混合工艺（例如机加工和直接能量沉积三维金属印刷）的生产率。旋转轴的测量位置和方向的误差以及主轴轴的方向的误差会在加工的工件中产生体积误差。如果要提高精度，则必须测量并补偿每个轴的偏差。在我们的方法中，使用仅需要控制旋转轴的三种方法来测量误差：在第一种方法中，不应用偏移来解决旋转轴的位置偏差；在第二，偏移量用于校正旋转轴的方向；第三，使用刀具补偿来校正主轴轴线的方向。我们开发了一种算法，该算法使用三个测得的数据集来识别PIGE。将该方法应用于混合型PKM，并对PIGE进行了测量和补偿。该技术使用简单的测量路径和顺序测量来校正旋转轴和主轴的轴误差，因此可以在工业中广泛使用。