5-DOF Manipulation of an Untethered Magnetic Device in Fluid using a Single Permanent Magnet

This paper presents a three degree-of-freedom (3DOF) closed-loop position and 2-DOF open-loop orientation control method for an untethered mockup magnetic capsule endoscope in fluid with a single permanent magnet positioned by a commercial robotic manipulator and a 3-DOF capsuleposition localization system. Using traditional methods known to roboticists, we study the kinematics of untethered magnetic manipulation using a single permanent magnet as the endeffector of a robot manipulator. We present a control method that maintains 5-DOF control of a magnetic capsule when the robot manipulator is not near a kinematic singularity, and seamlessly enables a capsule’s position to be controlled when the manipulator nears a kinematic singularity by sacrificing control over the capsule’s orientation. We demonstrate the method’s robustness to a control rate of 25 Hz, reduced localization rates down to 30 Hz, and the presence of manipulator singularities. 5DOF manipulation of an untethered device has been previously demonstrated by electromagnetic systems only. This work has applications for robotic capsule endoscopy of a fluid-distended stomach.