ENVIRONMENT RECOGNITION IN WELDING PROCESSES BY ULTRASONIC SENSORS

The welding process is one of the most interesting industrial problems that can be solved by robotic systems. This kind of process presents different sensory aspects as environment and parts recognition, seam l ocation and tracking, and obstacles avoidance. At the present time the re is not a simple sensor for all these requirements. Nevertheless som e measuring devices can satisfy particular needs. In this way, scannin g-laser systems are used for locating the welding seam, vision cameras supply a survey of the general environment, tactile devices can be us ed to detect close obstacles in the trajectory and electric measuremen ts by means of arc-furnish data for the fine control of the welding ac tivity and tracking movements. This paper describes an original develo pment and application-made in an Esprit project (Hephaestos I)-of an u ltrasonic sensor focused on the environment and parts recognition for trajectory definition and real-time obstacle avoidance for welding wor k in large ship-repairing plants.