An Optimal Design of an Electromagnetic Actuation System towards a Large Homogeneous Magnetic Field and Accessible Workspace for Magnetic Manipulation

Laliphat Manamanchaiyaporn,Tiantian Xu,Xinyu Wu

doi:10.3390/en13040911

Abstract

Untethered nano-/microrobots have been appealing to biomedical applications under magnetic guidance. Numerous actuation systems are specifically designed to generate either uniform or non-uniform fields which are unable to support all actuating mechanisms of magnetic robots. The size of their accessible space does not enable applications in life sciences (e.g., placing around human parts for tasks or an in vivo experiment in animals). Moreover, homogeneity of uniform magnetic fields is limited in a small region. Here, we propose an electromagnetic coil system that is optimally designed based on numerical simulation investigations to derestrict the mentioned constraints. The built-up system provides a large bore in which magnetic field generation by passing a 10 A current is strong enough for nano-/micromanipulation switchable between uniformity in a large-homogeneous region about 50-mm-wide along the x- and y-axes and 80-mm-wide along the z-axis, and with a non-uniformity of about 12 mT with 100 mT/m. It experimentally carries out potential and versatile controls to manipulate several commonly used microrobots that require a particular type of magnetic field to perform multi-DOF locomotion in diverse viscous environments. (e.g., helical propulsion by rotating magnetic field in the 3D-large workspace and in the complex network path, side-to-side sweeping-slip locomotion by oscillating fields, translation and rocking-slip locomotion by gradient-based fields). Besides, the system can be reproduced into any accessible space size regarding the square coil size to support diverse applications and guarantee the result in both uniformity of magnetic field in the large homogeneous region and a sufficiently strong gradient over the workspace.

Highlights

In the world of microorganisms, motion patterns of macroscale animals are hardly feasible since a high viscous force of biomedical fluid dominates, but those can swim [1]
A novel electromagnetic coil system is optimally designed for nano-/micromanipulation towards biomedical purposes which typically demand a large workspace, including a variety of magnetic field generations and control techniques
These features are what the other existing coils do not provide in a system such as the Tri-axial nested Helmholtz coil, which can only generate a uniform magnetic field, and its workspace engages with the coil radius

Summary

Introduction

In the world of microorganisms, motion patterns of macroscale animals are hardly feasible since a high viscous force of biomedical fluid dominates, but those can swim (e.g., undulation of Eukaryotic flagella, helical propulsion of Bacteria flagella) [1]. Energies 2020, 13, 911 stimulation (e.g., helical propulsion by rotating magnetic field, translation by magnetic force, undulation by oscillating magnetic field, reciprocal motion by periodical magnetic field) [2,3,4,5,6,7]. Magnetic actuation methods have been proposed in the diverse coil configurations with control techniques and specific types of magnetic fields to wirelessly power micro-/nanorobots. Industrial robotic arms mounted with a permanent magnet on the tip magnetically controlled a helical microswimmer to propel in fluid according to the programmed path [15,16]

Methods

Findings

Discussion

Conclusion