Kinematic modeling and error sensitivity analysis for on-machine five-axis laser scanning measurement under machine geometric errors and workpiece setup errors

摘要

On-machine scanning measurement of workpiece geometry has a strong advantage in its efficiency, compared to conventional discrete measurement using a touch-trigger probe. When a workpiece is rotated and tilted, position and orientation errors of the workpiece with respect to the machine's rotary axes can be a significant contributor to the measurement error. Rotary axis geometric errors also influence the measurement error. To establish the traceability of on-machine measurement with workpiece rotation, this paper kinematically formulates their contribution to measured profiles. As a practical application example, this paper presents the measurement error assessment for an axis-symmetric part. Based on the present kinematic model, this paper compares error contributors to the cases (1) where an axis-symmetric part is placed concentric to the rotary axis, and (2) where it is placed away from the rotary axis.