Development of an Electromagnetic Microrobotic Manipulation System

Abstract

To date, wireless magnetically-driven microrobotic manipulation of agents at the submillimeter scale is an emerging research. The potential application of this technology in precision medicine is immense, where microagents can be used as carriers for targeted drug delivery or as surgical tools for minimally invasive therapy and diagnosis. A challenging problem here lies in the providence of an effective microrobotic manipulation system with controllable magnetic field density and gradient as well as with a sufficient workspace. This dissertation investigates an enhanced electromagnetic microrobotic manipulation system for wireless, untethered manipulation of magnetic microbeads/microrobots within an enlarged workspace. The study is conducted based on the following three perspectives.

First, a prototype of magnetic manipulation system is developed. The system consists of six DT4E-core electromagnets arranged around a workspace, where the desired magnetic fields can be generated. Parametric optimizations of position, radius, and height of cores, which largely affect the magnet configuration performance of the designed electromagnetic system, are performed to achieve large workspace while maintaining high magnetic strength. With this optimized design, the workspace of the developed prototype can reach a spherical volume with a diameter of 110 mm, the magnetic field flux can reach 100 mT, and the magnetic field flux gradient can reach 2.5 T/m. Furthermore, the spatial distribution of electromagnetic field is investigated to establish an electromagnetic field distribution database. Such database enables the effective manipulation of microparticles in a considerably large workspace rather than only small central area.

Second, FEM analyzing model for simulating the generated magnetic field is developed. The FEM model is verified by comparing the modeling results and experimental results data. Homogeneity of each electromagnet can be obtained by measuring the magnitudes of the magnetic field flux at specified positions. Experimental results validate the linear correlation between the magnetic field distribution and the exciting current of each single coil.

Third, a study on fluidic dynamics at the submillimeter scale of microagents actuated by magnetic forces is investigated. A simple proportional and integral (PI) controller is employed for the automated motion control of the microagents. In vitro experiments of tracking paramagnetic microbeads along desired trajectories in both 2D (two-dimension) and 3D (three-dimension) scenarios are performed. These experiments have well demonstrated the capability of the developed system in precise tracking control.

This dissertation has laid out a solid foundation for the investigation of electromagnetic actuated microrobotic manipulation, and contributed to the further development of precise medicine.

Date of Award	15 Nov 2017
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Dong SUN (Supervisor) & Jie Yang (External Supervisor)