Accuracy Improvement of Coordinate Measuring Machines Applied to Reverse Engineering Systems

• Main Authors: Chun-Hung Kuo, 郭俊宏
• Other Authors: 呂志誠
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/u83s7z

碩士 === 國立臺北科技大學 === 精密機構設計產業研發碩士專班 === 95 === This thesis aims to present an effective method to improve measurement accuracy of a CMM applied to the reverse engineering system based on operational functions of the current CMM. Measuring steps include the construction of a preliminary surface formed by initial CMM measurement, obtaining spatial data of planned points on the surface, deriving the normal vectors of these planned points, driving probe movement along the normal vectors for another measurement and completion of accurate radius compensation for the probe head, such that all steps are able to reduce the compensation errors caused by incorrect contact points assumed. For instance, a standard sphere is taken as a example to demonstrate and verify the research methodology by using the fitting method between point data and the target surface. Next, two usual examples made of B-spline surfaces are successfully completed for the proof of research feasibility. It is clearly indicated that measuring errors can be rapidly decreased and converged to several micrometers through repeated measurements. Finally, the studied method can be applied to metal-based free-form components suitable for CMMs. In addition to accuracy improvement, the research is able to integrate the non-contact optical measuring systems to meet various measurement requirements for a variety of work-piece materials.