Pose calibration of line structured light probe based on ball bar target in cylindrical coordinate measuring machines

Abstract

Non-contact measurement has shown great advantages in term of high efficiency measurement. In order to obtain the 3D point cloud efficiently, line structured light probe has been widely used in coordinate measurement machine, which is mounted on the end of the motion axis. However, the installation errors of the probe seriously affect the measurement accuracy. Hence, probe pose error compensation is essential. In this paper, a novel calibration method is proposed to compensate the installation errors. First, the system transformation relationship between the probe coordinate system and the workpiece coordinate system is established. Then, the probe pose is calibrated in the cylindrical coordinate measuring machine. The ball bar is adopted instead of a single sphere to avoid no solution of the probe pose in cylindrical coordinate measuring machines. After obtaining the initial value, an optimal multi-objective function is constructed to optimize the pose errors and sphere centers. The proposed method is easy to operate and has high accuracy which is evaluated in a set of experiments.