The small size of the work volume of micro/meso-scale machine tools often presents problems for calibration and error compensation, but at the same time provides opportunity for solutions not practical on the traditional scale. Measuring tool position with a separate metrology frame and compensating for error motions, the concept presented in this paper, is one such solution. The design of the metrology frame has measurement sensors symmetrically distributed around the work volume, all pointing directly to the tool tip, measuring the position of the tool tip with respect to the workpiece, thus bypassing the structural loop and minimizing Abbe offset errors. Forward and inverse kinematics provide the relationship between the metrology frame measurements and machine tool Cartesian coordinates. Error analysis reveals that sensor error has a direct influence on measurement accuracy while metrology frame misorientations have only a second order influence.
Citation: International Journal of Mechatronics and Manufacturing Systems
Pub Type: Journals
metrology frame, micro/meso-scale machine tools, micromanufacturing, Abbe offset errors, Abbe alignment principle, kinematic design