“Intelligent robotic assembly” indicates a complete degree of autonomy and a high adaptability in performing assembly tasks. For instance, a highly flexible and intelligent assembly system appears to be one that can autonomously perform any assembly work in entirely unstructured environments. This system does not require organized, orderly forms of part transport and presentation devices, such as assembly jig and fixture, part feeding devices, tray, magazine, conveyor, etc., but needs only an assembly table where parts to be assembled are stacked up in a cluttered manner.