Enhanced Motion Control of Magnetically Actuated Capsule Robot Using MEMA—A Mobile Electromagnetic Actuation System

摘要

Magnetic capsule robots (MCRs) have been widely studied in recent years for medical use since they can perform noninvasive procedures and patient-friendly diagnostics. Magnetic actuation, which is one of the most reliable wireless motion control techniques for a magnetic capsule endoscope in the body, has also been extensively studied. However, there are challenges associated with cooperativeness with clinicians and convenience for patients, especially since a large workspace is required with a small actuation system. To achieve unobtrusive actuation of MCRs, we propose a method, which involves the use of a novel mobile electromagnetic actuation (MEMA) system, for enhancing motion control of a magnetically actuated capsule robot. This actuation system comprises a robotic arm, a motorized <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">XY</i> linear stage, and electromagnetic coils, and it can provide a movable workspace on both sides of a patient's bed. A disturbance observer based robust feedback controller was also designed to compensate for the hardware singularity and model uncertainty of a multiple magnetic field model. The MEMA system and controller can help accurately operate an MCR at all locations—on the floor, wall, and ceiling—of the target volume. Translational and rotational motions of an MCR were experimentally achieved, and the maximum angular scanning error of 0.87° could be achieved with the proposed control. Finally, the practicality of the MEMA system for enhanced endoscopic motion could be validated through a hybrid control scheme.