Kinematic model and calibration of an articulated arm coordinate measuring machine

Based on D-H (Denavit-Hartenberg) notation, the measurement model and calibration technology for a seven-axis articulated arm coordinate measuring machine (AACMM) were researched. The number and definitions of kinematic model parameters were further studied. Simulation experiments revealed a special problem: some parameters can not be effectively identified by direct calibration. To solve the problem, a vertical rod was made and fitted into the probe to identify all parameters of the seven-axis AACMM. Finally, the probe was calibrated by placing the straight rod back and the probe parameters could be obtained. Not only can the experiments prove that the method presented can guarantee the precision of the AACMM with seven axes by identifying all parameters, but they can also verify the validity of the kinematic model.