<title>Vision-guided, semiautonomous system applied to a robotic coating application</title>

摘要

This paper describes a new semi-autonomous, calibration-free system which integrates a user-friendly graphical interface, several cameras, a laser pointer mounted on a two-axis pan/tilt unit, and a six degree-of-freedom robot. The details of the system are discussed in reference to the problem of coating a workpiece of unknown geometry that is positioned arbitrarily with respect to the robot and the vision sensors. The remote user specifies the region of the workpiece that is to be coated simply by 'pointing' and 'clicking' on the region of interest as it appears in a single image on the user's computer monitor. By means of a simple and robust control strategy, the laser pointer mounted on the pan/tilt unit is autonomously actuated to a user-specified number of approximate positions in the region of the surface of interest. This is used to create compatible maneuver objectives in the participating vision sensors. Then, using the method of camera-space manipulation, the robot is controlled to make several passes across the region. Regardless of the geometry of the workpiece, the manipulated nozzle always remains perpendicular to the surface at a user- specified distance from the surface. Upon completion of the coating process, the laser pointer is again actuated to pass through a specified number of points on the new surface. This information is used to make a very precise inference of the thickness of the build-up of the coat that has been applied. If the coat is not sufficiently thick, the robot makes more passes as required. The paper also presents experimental results of the high accuracy of position and orientation control of the manipulated tool, as well as the depth inference of the surface coat applied.