Robot accuracy evaluation using a ball-bar link system

Abstract

SUMMARY Relatively large errors can exist in industrial robots as a result of mismatch between the controller model and the corresponding physical model. The paper outlines a novel approach for accuracy assessment and adjustment of multiaxis industrial robots through a low-cost ball-bar link system. The features of the ball-bar, which incorporated a 12 mm range digital displacement transducer in conjunction with a PC, are discussed. The ball-bar device was used in both a trammelling and circular mode of operation. This produced data which not only related to the accuracy of the robot but also enabled joint errors to be significantly reduced.