To solve the problem of inflexibility of offline hand-eye calibration in "eye-in-hand" modes, an online hand-eye calibration method based on the ChArUco board is proposed in this paper. Firstly, a hand-eye calibration model based on the ChArUco board is established, by analyzing the mathematical model of hand-eye calibration, and the image features of the ChArUco board. According to the advantages of the ChArUco board, with both the checkerboard and the ArUco marker, an online hand-eye calibration algorithm based on the ChArUco board is designed. Then, the online hand-eye calibration algorithm, based on the ChArUco board, is used to realize the dynamic adjustment of the hand-eye position relationship. Finally, the hand-eye calibration experiment is carried out to verify the accuracy of the hand-eye calibration based on the ChArUco board. The robustness and accuracy of the proposed method are verified by online hand-eye calibration experiments. The experimental results show that the accuracy of the online hand-eye calibration method proposed in this paper is between 0.4 mm and 0.6 mm, which is almost the same as the offline hand-eye calibration accuracy. The method in this paper utilizes the advantages of the ChArUco board to realize online hand-eye calibration, which improves the flexibility and robustness of hand-eye calibration.
Keywords: ChArUco board; hand–eye calibration; robot.