旋轉台幾何誤差之量測與探討

Abstract

旋轉軸的使用目前已經被廣泛地應用在工業，像是機器人手臂、工具機或三次元量測儀。一些曲面切削，如蝸輪機葉片或螺紋，現在都可以透過多軸工具機來完成。而為了進一步提高工具機的精度，必要探討旋轉軸的幾何誤差，因此如何量測到旋轉軸幾何誤差是一個關鍵。目前已經不少學者提出各種旋轉軸幾何誤差的量測方法，當中有些方法更是可以達到相當高的解析度。 在本研究中，首先建立了旋轉軸幾何誤差的量測系統，可以量測旋轉軸偏擺誤差與偏心誤差。偏擺誤差量測系統有三種方法，分別是使用千分錶、多面稜鏡搭配自動視準儀和塊規搭配自動視準儀三種。偏心誤差量測系統有兩種方法，分別是使用千分錶搭配標準球，以及使用雷射光、四象限感測器再搭配角耦稜鏡作為反射鏡。在量測過程中，一些架設誤差會導致量測結果的不穩定，因此必須盡可能減小或排除。從量測結果的分析與比對中，可以評估量測方法的可靠性。另外也在這些量測結果中，找出旋轉軸幾何誤差之間的關聯。這些結果可作為日後分析旋轉軸誤差的基礎。

Rotary axes are widely used in industry, such as in robotic arm, machine tool and coordinate measuring machines (CMM). The cutting of special curved surface, like turbine blade or helical thread, could be performed through multi-axis machine tool. To improve the accuracy of machine tools, it is important to research on the geometry errors of rotary axes. Consequently, how to measure the accuracy of rotary table is essential. There are some measurement systems that had been developed and some systems can reach high resolution. In this study, several measurement systems have been developed, some can measure tilt error and the others can measure eccentric error. There are three kinds of tilt error measurement systems, one using dial gauge, another using polygon and autocollimator, the other using gauge block and autocollimator. There are two kinds of eccentric error measurement system, one using dial gauge and master ball, another using laser diode, QPD and corner cube as reflector. In the measurement process, some setting errors cause the measurement results unstable. Therefore, it is important to minimize or eliminate setting error. Through the analysis and comparision of measurement results, it can be used to evaluate the reliability of the measurement system, and find out the correlation between linear errors and angle errors of axes. The result can be used as the basis of analyzing the errors of rotary axis in the future.