의료용 마이크로로봇의 무선 구동을 위한 전자기구동시스템의 개발 및 응용

Abstract

Utilization of microrobots in biomedical applications ranging from biological molecule manipulation to medical treatment of the human body has attracted great attention worldwide. Microrobots are untethered small devices composed of magnetic materials and supporting structures. They are considered to be promising to replace conventional biomedical technologies, because they can be wirelessly manipulated by external magnetic fields and can work in remote area in a controlled manner, which could not be realized in conventional biomedical technologies. Microrobots are expected to conduct various complex tasks such as targeted drug delivery, precise cell manipulation, targeted tissue biopsy, remote stent deploying, enhanced unclogging, local sensing, etc. And their real applications become more feasible with the aid of significant advances in micro- and nanoscale processing, manufacturing, and utility technologies. Firstly, this dissertation presents the background of the dissertation covering the definition, advantages, applications, and principles of biomedical microrobots. The magnetic torque and force exerted on a magnetic dipole moment in an external magnetic field can be utilized to manipulate microrobots. Secondly, this dissertation develops two saddle-shape electromagnetic coils referred to uniform and gradient saddle coils which can generate uniform magnetic field and linear magnetic gradient, respectively, required for the effective generation of magnetic torque and force of a microrobot. By combining these coils with conventional Helmholtz and Maxwell coils, this dissertation also develops a novel magnetic navigation system (MNS) which can generate various magnetic fields to generate various microrobot motions. Then, it experimentally verifies the proposed MNS and examines the performance of the proposed MNS compared to a conventional MNS by demonstrating controlled translational and helical motions of a microrobot. Finally, this dissertation proposes two novel structures of microrobots which can be actuated by the proposed MNS. A double helical magnetic microrobot was developed to achieve drug-enhanced unclogging abilities for occlusive vascular diseases in human blood vessels. Rotational dynamic constraint equations of the microrobot was investigated to selectively manipulate the navigating, drug releasing, and mechanical drilling motions of the microrobot by simply controlling the ERMF. A self-positioning and rolling magnetic microrobot working on thin three-dimensional surfaces was also developed. This microrobot can effectively anchor or move on an arbitrary thin three-dimensional surface by overcoming external forces, which can be greatly useful for the targeted drug or object delivery in complex surface environments. Experiments demonstrating the controlled motions of the microrobot were conducted to verify the proposed microrobot mechanisms.