Independent Electromagnetic Field Control for Practical Approach to Actively Locomotive Wireless Capsule Endoscope

Toward wireless medical microrobot applications driven by an electromagnetic actuation (EMA) system, challenges associated with movability, the electromagnetic force, and the coil system size must be addressed. This paper presents an enhanced EMA system with a higher magnetic field via new coil configurations, an independent magnetic field control method, and application to the multi-degree-of-freedom (DOF) motion of an untethered capsule endoscope. The magnetically actuated capsule endoscope (MACE) system proposed herein consists of an endoscopic capsule with a permanent magnet in the body, eight air-cored stationary electromagnetic coils, and a control system. The coil system is designed to maximize the working space available within a limited equipment space. The MACE is designed to perform full 5-DOF motion, including 3-DOF translation and 2-DOF rotation. The independent magnetic field control method with the new coil configuration enables orientation-independent-driving (OID) control of the capsule endoscope that could not be accomplished by previous EMA systems. The developed system performance was verified by simulations and experiments. The MACE motion in the spatial domain was evaluated with a robotic endoscopic procedure and diagnostic performance by in-vitro and ex-vivo experiments.