本論文的研究目的為改善五軸工具機之幾何精度。五軸工具機雖已廣範應用於工業界，但其相關之研究卻相當匱乏，其主因是五軸工具機同時具有線性軸及轉動軸，其機構間之交互影響造成複雜之誤差模型及增加補償機制實現之困難度。同時，此一複雜之機構鏈亦造成總成誤差之量測幾乎不可能達成。
因此，本論文中，發明一命名為探頭-球桿(Probe-ball)之誤差量測裝置，此裝置可直接量測五軸工具機之三維定位誤差，為說明其量測結果，進而推導其數學模型。此外，為有效估算幾何誤差量，將量得之誤差帶入誤差模型中，則得到只具有不能量測且未知之誤差項之簡化誤差模型，再藉由探頭-球桿量得之數據及最小平方估算法得到未知之誤差項。此時，完整之五軸誤差模型建立完成。最後，進行五軸工具機即時誤差補償。量測結果顯示，此一補償機制大大改善五軸工具機之精度。

This paper is devoted to enhance the accuracy of five-axis machine tools. Although five-axis CNC machine tools are widely used in mold and die industry, relevant works in the field of the enhancement of accuracy of five-axis machine tools are sparse. The reason is on one hand the interaction of linear and rotary axes complicates the relationship between the sources of errors and the final errors at the tooltip and makes it difficult to find a suitable compensation method. On the other hand, the increasing kinematical complexity makes it very difficult to measure the overall positioning errors.
In this paper, a new measurement device, the probe-ball, is presented which can be used to measure directly the overall position errors of five-axis machine tools. To explain the nature of the probe-ball error measurement, a theoretical model is derived with the HTM method. After setting all measured errors in the error model, a reduced error model is defined which describes the influence of each unknown and not measurable link error on the overall position errors. The unknown link errors can be estimated based on the probe-ball measured data using the least square estimation method. Based on the fully known error model, a new error compensation strategy using linear function is proposed. This compensation method is simple and implemented in real-time. The test results show the positioning accuracy of the five-axis machine tool can be improved dramatically.

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