Automated calibration of a lightweight robot using machine vision

Calibration of industrial robots can greatly reduce commissioning time by avoiding expensive online programming. This article presents an approach to automating the measurement and compensation of kinematic errors, applied to a lightweight robot arm. A measurement station is designed to automate this calibration process. The measurement is based on the detection of a chequerboard pattern in camera images of the end-effector. An electronic description of the robot including its individual compensation parameters is then provided in the standardised format AutomationML and transmitted via OPC UA. The approach requires only minimal manual input and is shown to significantly improve the positioning accuracy of the robot.