A combined calibration method of a mobile robotic measurement system for large-sized components

Abstract

Product quality control of large-sized components with complex supports requires automatic and accurate 3D shape measurement. For accurate and efficient measurements of key local features (KLFs) on the mounting surface of multiple supports, we propose a flexible measurement method combining a laser tracker, a 3D scanner, and a mobile robot system. As for improving the overall measurement accuracy, we also introduce a calibration method based on a multidimensional combined collaboration target (MCCT) to establish correlation constraints between global and local calibration. Specifically, a global calibration method based on multidimensional geometric constraints provides a global measurement field. Additionally, a local calibration method derived from combination optimization model achieves accurate calibration of extrinsic parameters. We constructed the corresponding mobile robotic measurement system (MRMS) and conducted experiments. The experimental results demonstrate that the maximum and mean calibration errors are reduced from 0.045/0.0261 mm to 0.0231/0.0122 mm within 7 m, which features high accuracy.