Edward Bernardon

Vision Guided Manipulation of Non -rigid Parts: A Case Study

The vision guided manipulation of rigid objects has been widely studied, but the robotic handling of flexible materials such as cloth has received far less attention. Draper Laboratories has developed a vision guided, fully-automated folding-sewing device for the construction of suit sleeves. A set of robot motions requiring only 2-D vision data has been developed. A specially designed robot manipulator working in tandem with a vacuum table allows the sleeve to be held flat for image acquisition. The robot motion sequence also allows robot moves to be based on locations on the workpiece contour rather than its interior. Binary image analysis software models the contour as smooth curves connected at discontinuity points called breakpoints. Syntactic pattern recognition techniques are used to match breakpoints to a stored database and return location data on those breakpoints required by the robot or sewing modules. Work has also begun to use grey scale values to achieve sub-pixel accuracy.