APPARATUS AND METHOD TO COMPENSATE BEARING RUNOUT IN AN ARTICULATED ARM COORDINATE MEASUREMENT MACHINE

A method and apparatus for correcting errors in a bearing cartridge used in a portable articulated arm coordinate measurement machine (AACMM) is provided. The method includes providing a cartridge having a first bearing and a second bearing arranged in a fixed relationship to define an axis, the cartridge further including an angle measurement device configured to measure a rotation of a portion of the cartridge about the axis. A plurality of angles is measured with the angle measurement device. A first plurality of displacements is determined at a first position along the axis, each of the first plurality of displacements being associated with one of the plurality of angles. Compensation values are determined based at least in part on the plurality of angles and the first plurality of displacements.