| 摘要 |
In some embodiments, an apparatus and a system, as well as a method and an article, may operate to select a longitudinal axis (250) within a borehole (220), and to move a down hole housing using at least one set of rollers (82) attached to the housing to contact a surface of the borehole (220), so that simultaneous movement with two rotational degrees of freedom is enabled within the borehole (220). The centerline of the housing can be substantially aligned with a selected longitudinal axis (250) while the housing moves along the selected longitudinal axis. Additional apparatus, systems, and methods are disclosed. |
