Redundant Electromagnetic Control of an Endoscopic Magnetic Capsule Driven by Multiple Electromagnets Configuration

In this article, we present a novel stationary electromagnetic actuation system (EMS) and a redundant magnetic field control approach that can enhance the magnetic actuation ability for a capsule endoscope. The EMS configured with multiple electromagnets has an intrinsic redundant problem when computing input current to each coil from inverse formulation. Here, we propose a redundant electromagnetic field control scheme of utilizing this redundancy to increase magnetic force and reduce the peak input current that deteriorates the performance. It is based on the optimization of magnetic field encountering input current and null-space equations of a pseudoinverse matrix. We validated the proposed methods in simulation and experiments through the prototyped EMS designed by considering actual human size and a magnetic capsule endoscope. The results show significant improvements in the magnetic field and lower input current compared to the conventional method as well as extended operating time through reduced heating effects. Especially, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vitro</i> in a gastric phantom and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> experiments in a live pig could prove the practical applicability of the developed method for a magnetic capsule endoscope toward upper stomach diagnosis in the clinical environment.