(A) new omni-directional image sensing system for assembly of parts with arbitrary cross-sectional shapes(OISSA)

Abstract

To accomplish assembly tasks successfully with adapting to their changes, it is essential to accurately estimate and compensate the shape of a part, the distance from a sensor to a part, and the misalignment in position and orientation between mating parts, caused by uncertainties such as modeling errors, control errors and manufacturing tolerances. However, it is difficult to discern their information with respect to mating parts with complicated cross-sectional shapes, in contrast with relatively simple cross-sectional shapes. Therefore, it requires an omni-directional information instead of a local information in order to obtain these information. To this end, assembly requires an omni-directional sensing system that is capable of obtaining not only 2p relative geometrical information between mating parts along their mating boundary interfaces, but also a 2p image of a part, regardless of the complexity of the shape. This need motivates the development of a new sensing method for detecting misalignments generated in assembling parts with complicated shapes. In the area of assembly, such a method has not been fully developed yet; mostly, only local sensing techniques using proximity, tactile, force, and vision sensors have been developed, and they are also not suited for assembling parts with complicated shapes because they need an additional motion and a complex image composition to obtain the omni-directional information. This thesis proposes a new omni-directional image sensing system capable of immediately obtaining a 2p coaxial image without self-occlusion between mating parts and accurately estimating the shapes of a part, the distance from the sensor to the part and the relative misalignment between mating parts, with respect to the 2p coaxial image. This sensing system was designed by an analytical method and implemented by utilizing a camera encompassed with an optical unit, consisting of a pair of conic mirrors and a pair of plane mirrors, attached...