Six-Degree-of-Freedom Localization of an Untethered Magnetic Capsule Using a Single Rotating Magnetic Dipole

This paper presents a method to estimate the six-degree-of-freedom pose of a magnetic capsule, with an embedded permanent magnet and Hall-effect sensors, using a rotating dipole field. The method's convergence properties as a function of the number of distinct rotation axes of the applied field and the number of complete rotations about each axis are characterized. Across our tested workspace, the localization error was 4.9 +/- 2.7 mm and 3.3 +/- 1.7 degrees (mean +/- standard deviation). We experimentally demonstrate this is sufficient for propulsion of a screw-type magnetic capsule through a lumen using a single dipole to both propel and localize the capsule.