Study on Advanced Coordinate Metrology

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The aim of this research project was to clarify the essense of coordinate metrology and to propose advanced coordinate measuring system. For this aim, the following sub-researches were done ;(1) A new software datum method for on-machine measurements of roundness, whichis called the combined 3-point method, has been proposed. This method can accurately measure roundness profiles that include step-wise variations. A roundness measurement system have also been developed.(2) Using computer simulations by FEM.the thermal and stress deformations of nano-CMM are calculated. From these simulations, the prototype of nano-CMM has been developed. Novel data processing method has been developed to calculate the form deviations using statistical method. This method can be used for the evaluations of measurement uncertainties and a computational tolerancing.(3) A comparative length measurement instrument using a regular crystalline lattice as a reference scale and a STM asa detector has been developed. The experimental results using the instruments show feasibility for 1mum range comparative length measurement with sub-nanometer resolution.(4) A new non-contact probe called "optical ring image sensor" for 3-D CMM was developed, which can measure accurately 3-D edge profile as well as 3-D surface profile of the free form surfaces with steep inclination angles and edges.(5) A new style of measurement system combined with a coordinate measuring system and a miniature robot with microprobe was developed to extend those machine capabilities to sub-micron accuracy over wider working range.(6) A multi-degrees-of-freedom fine motion table for three dimensional measurement is examined. Control strategy against disturbance to the table are also examined.(7) For clarifying the effect of thermal deformation on CMM's measuring accuracy, a virtual CMM with FEM was developed in a supercomputer. Using the virtual CMM,the effects under many kinds of the thermal conditions were examined.