Development of Welding Profile Measuring System with Vision Sensor

This paper describes the development of the 3D measurement system for welding robot. The system consists of PC based vision camera and stripe-type laser diode. The total system is assembled into a compact module which can be attached to the head of welding robot system. Especially, this system is designed to operate at different working distances. For this purpose, the mechanism which adjusts the focal length and the relative location between camera and laser diode is devised. These two configurations are changing according to current working distance automatically. Most parts of image processing such as camera calibration, correction of distortion, and line extraction are implemented and running on PC. After measuring the welding profile, the three dimensional shape of the work piece is obtained and some useful features for robot manipulation are calculated. Some experiments are carried out and some applications are given.