C-space characterization of contact preserving paths with application to tactile-sensor based mobile robot navigation

This paper considers the navigation of a three degrees-of-freedom mobile robot equipped with position and tactile sensors in an unknown planar environment. The paper focuses on the contact preserving segments of the robot´s path. Any contact preserving path can trace a single or two simultaneous contacts. The paper establishes that motions involving two contacts induce two types of configuration-space curves: contractible loops representing passable gaps, and non- contractible loops representing impassable gaps. The paper identifies a generic class of contact preserving paths which requires only single-contact tracings with efficient transitions at double-contact configurations involving impassable gaps, and at triple-contact configurations involving both passable and impassable gaps. A preliminary tactile-sensor navigation algorithm based on these paths is illustrated with an example.