The Implementation of a Visual Sensing System for 3-D Control of the RTG Crane

The fundamental function of the RTG crane is to direct the laden or unladen spreader onto the top of the target container. However, one of the most difficult, yet crucial, aspects of any experimental test system is invariably the practical arrangement required for measuring the swing angle of the cable. In this paper, not only the concept for a visual sensing system is proposed, the search mechanism for fast locating the center of the moving spreader underneath are also provided. Combined with dynamic model done in previous work, it outlines a closed-loop automatic system capable of guiding the spreader of a RTG crane onto the location of the target container by using the feedback signals from the actuated degrees of freedom, as well as the position and orientation of the swinging spreader by means of a visual sensing technology