Modelling and Analysis of the Geometrical Errors of a Parallel Manipulator Micro-CMM

A micro coordinate measurement machine (micro-CMM) with high precision and high accuracy is introduced for the measurement of part dimensions in micro scale. This design is intended to achieve submicron resolution for a work envelop of at least (100x100x100) mm. In this study, a mathematical measuring model to explicitly define the coordinate of the probe in x, y and z directions have been represented. An algorithm to find the workspace was implemented. The error model of the machine was created and the effect of structural errors on probe position was studied analytically. The significance of each geometric parameter was studied in order to minimize the measuring error and achieve the best machine design. Finally, the results of the analytical error model were confirmed through a Monte Carlo analysis.