%0 Journal Article %T Experimental validation of a 3-D vision-based measurement system applied to robot calibration %A Motta %A J. M. S. T. %A McMaster %A R. S. %J Journal of the Brazilian Society of Mechanical Sciences %D 2002 %I Scientific Electronic Library Online %R 10.1590/S0100-73862002000300011 %X one of the problems that slows the development of off-line programming is the low static and dynamic positioning accuracy of robots. robot calibration improves the positioning accuracy and can also be used as a diagnostic tool in robot production and maintenance. a large number of robot measurement systems are now available commercially. yet, there is a dearth of systems that are portable, accurate and low cost. in this work a measurement system that can fill this gap in local calibration is presented. the measurement system consists of a single ccd camera mounted on the robot tool flange with a wide angle lens, and uses space resection models to measure the end-effector pose relative to a world coordinate system, considering radial distortions. scale factors and image center are obtained with innovative techniques, making use of a multiview approach. the target plate consists of a grid of white dots impressed on a black photographic paper, and mounted on the sides of a 90-degree angle plate. results show that the achieved average accuracy varies from 0.2mm to 0.4mm, at distances from the target from 600mm to 1000mm respectively, with different camera orientations. %K robot calibration %K 3-d machine vision %K absolute accuracy %K camera calibration %K robotic measurement systems. %U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0100-73862002000300011&lng=en&nrm=iso&tlng=en