Dimensionality reduction calibration of a robotic grinding head’s 3D coordinate system using a 1D laser sensor

Abstract

The demand for highly accessible grinding in confined spaces, such as integral blisks, has driven research and applications in robotic grinding and polishing using a grinding head. Achieving high-precision and low-cost calibration of the grinding head is a primary challenge. Consequently, a novel dimensionality reduction calibration method is proposed. This method employs a 1D point laser displacement sensor to calibrate the 3D grinding head coordinate system. Firstly, a hand-eye calibration method for the sensor is proposed. The “fitting and one-step rotation method” determines the rotation axis and angle through the fitting, followed by one-step rotation to make the flange plane parallel to the laser emission plane, thereby completing the sensor orientation calibration. The “two-step rotation method” aligns the flange center with the measurement origin of the sensor to complete the sensor position calibration. Subsequently, the 3D grinding head coordinate system is calibrated with the pre-calibrated sensor as an intermediary. The “two-step translation method” makes the grinding head’s end face parallel to the laser emission plane, completing the grinding head’s orientation calibration. The “spatial three-point method” aligns the grinding head center with the sensor’s measurement origin, completing the grinding head’s position calibration. Finally, the experiments demonstrate that the precision of hand-eye calibration can be maintained within 0.178 mm and 0.6°, while the accuracy of the grinding head calibration is within 0.08 mm and 0.4°. The calibration method provides high precision, low cost, and reliable stability while supporting programming for rapid calibration, thereby facilitating the high-precision automation of robotic grinding and polishing.