Three-Dimensional Method Combining Linearly Structured Light Sensing and Rotary Scanning for Measuring Aviation Bearings

The geometric parameters of aviation bearings need to be accurately measured to ensure that the bearings are correctly assembled for reliable operation and quality purposes. This study aimed to solve the problems presented by the low accuracy and low efficiency of the existing method while avoiding the error introduced by the deviation of the measurement beam from the center of the aviation bearings during measurement. This method determines the spatial posture of the axis of the rotary table using linear structured light sensing and extracts the spatial point-cloud data of the aviation bearings based on rotary scanning. We propose algorithms for spatial property determination and point-cloud segmentation. To avoid the error caused by the deviation of the measurement beam from the center of the aviation bearings, the point-cloud data are transformed to a new coordinate system prior to extracting the features of the datum plane and raceway. An aviation bearing is measured to verify the validity of the proposed method. The radius and eccentricity of the raceway are 4.900 and 0.010 mm with experimental standard deviations of 0.002 and 0.001 mm, respectively. For comparison purposes, experiments with a coordinate measuring machine (CMM) and contourgraph were also performed. The expanded measurement uncertainty considering the repeatability, reference instruments, and temperature drift is
$1.6 \mu \text{m}$
. The proposed method can be extended to precision noncontact measurements of workpieces with rotary structures.