Calibration of Articulated Arm Coordinate Measuring Machine Considering Measuring Posture

Three-dimensional Coordinate Measuring Machines (CMMs) are widely used to measure wide-ranging accuracy. Parameters describing CMM use mechanisms must be calibrated by measuring artifacts for the target CMM. Most CMM calibration studies have covered orthogonal rather than non-orthogonal CMMs. We focused on calibration for a nonorthogonal articulated-Arm CMM (ACMM), which has more measurement freedom than an orthogonal CMM, although ACMM measurement error exceeds that of orthogonal CMMs. The kinematic parameters of ACMM are calibrated using spherical center coordinates as the artifact. Part of the measuring volume is calibrated, but the ACMM is not sufficiently calibrated. To calibrate arm deformation in different measurement posture as well as kinematic parameters, we produced a new artifact for which we propose calibration confirmed in experiments.