影像式3D量測儀精度校正與應用

Abstract

工具機位置定位或成品檢驗量測時，失之毫里則差之千里，故需靠精密量測儀器檢驗校正是否合乎標準，因此量測儀器本體的精度是值得研究探討。目前本實驗室(電腦整合設計與製造研究室)發展的影像式3D量測儀，利用AC伺服馬達驅動滑軌上的承載平臺，以DVT公司所發展的智慧型影像處理攝影機配合量測機構及個人電腦為輔助，而達到3D影像量測系統自動化。然而承載平臺的位移或量測儀旋轉座，所造成之直線位移誤差與空間誤差，影響量測儀精度甚大，本文首先利用實驗室原有影像量測儀進行改裝，在A軸L型座上設計裝置 、 方向微調機構，有效而簡便地將攝影機位置定位誤差的變異值進行歸零調校。實驗方面則將原圓形量測目標物，改為長方形並增加角位移的量測，同時研製輔助校正的機構，建立新型的幾何誤差量測校正與方法，配合統計方法進行元件與系統的精度分析與調校。在600mm量測距離歸零校正時，整體重現性量測精度提昇至610μm，實際應用在空間座標量測範例時，整體的最大誤差約在650μm以內。成果可應用於物件空間座標量測、工作母機機台水平度、垂直度之校正、網路遠距量測及移動物體的動態位移即時量測等。

The precision of tool machine has been improved from micrometer(μm) into nanometer(nm) under the request of semiconduct and micromachining industry recently . A small discrepancy will lead to a great error, so calibration of precision measurement instrument is necessary. This paper proposes a novel calibration technology for a new kind of 3D measurement system developed by CIDM Lab. The 3D measurement system composes of two microstepping motors and an AC servomotor to drive the smart CCD camera to assigned position. This measurement system is capable of 3D coordinate measurement and moving objects tracking automatically. However, sliding and rotational errors of the positioning mechanism are the critical precision issues of this system. The system has been carefully reconstructed and added on some fine tune mechanism to improve the position accuracy of smart CCD camera. Furthermore, the external and internal factors of measurement accuracy are also studied and identified by using statistical method. Presently, this measurement system can be applied to measure the point coordinate of a 3D object within 600 mm distance with the maximum error less than ± 50μm. The proposed image type 3D measurement machine can be applied to geometry alignment of machine assembly etc. effectively and efficiently.