Identification of a new kinematic model of an articulated arm coordinate measuring machine using the R-test instrument   Ryuichi Saito, Soichi Ibaraki       Abstract   The articulated arm coordinate measuring machine (AACMM) is a robot-arm type CMM with excellent portability and flexibility for human-operated measurement. However, the measurement accuracy of the AACMM significantly worse than that of conventional CMMs with comparable measurement ranges. To improve the measurement accuracy of AACMMs, model-based corrections have been presented in many studies. To improve the prediction accuracy of the model, calibration tests must be performed with higher accuracy. Therefore, in this paper, a calibration device to measure the three-dimensional displacement of the end effector sphere, whose position is nominally constrained in a sphere socket, by three displacement sensors, is designed and fabricated. The second contribution of this paper is on the proposal of a new kinematic model of an AACMM containing the angular measurement error of rotary encoders in AACMM joints. By experiments, it was found that the proposed model has a potential to further reduce the length measurement errors over the entire workspace, compared to the conventional model.   Keywords: Articulated Arm Coordinate Measuring Machines, Kinematic Calibration, R-Test, Error correction         >> Back to Home