Calibrating a Cartesian robot with eye-on-hand configuration independent of eye-to-hand relationship

Abstract

A novel approach is described to geometric calibration of Cartesian robots. This is one-third of an overall approach to real-time 3-D robotics eye, eye-to-hand, and hand calibration, which uses a common setup and calibration object, and is especially suited to machine vision community. The robot makes a series of automatically planned movements with a camera rigidly mounted at the gripper. At the end of each move, it takes a total of 90 ms to grab an image, extract image feature coordinates, and perform camera extrinsic calibration. After the robot finishes all the movements, it takes only a few milliseconds to do the calibration. Only one single rotary joint is moving for each movement while the robot motion can still be planned such that the calibration object remains within the field of view. This allows the calibration parameters to be fully decoupled, and converts a multidimensional problem into a series of one-dimensional problems. Eye-to-hand transformation is not needed at all during the computation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>