In this paper, we proposed a new device for geometry errors measurement and coaxiality evaluation, and the corresponding methodology for coaxiality evaluation from measurement data is presented, which allows to characterize multiple holes at a time. Unlike traditional measurement system a laser sensor is mounted onto out of the holes so that multi-hole surfaces can be “seen” by the senor when it rotates around a fixed axis. First the intersections (or ellipse profiles) of the sensor’s scanning plane and holes, are computed by fitting. Then, the center coordinates and profile points of the ellipse are computed and transformed to the 3D global coordinate frame. Finally the centerline of the hole is determined from the 3D profile points by using a weighted least-squares fitting algorithm. In addition, to reduce the effect of noises on the measurement result, error analysis and compensation techniques are studied to improve the measurement accuracy. A case study is presented to validate the measurement principle and data processing approach.
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