Improving guidewire-mediated steerability of a magnetically actuated flexible microrobot

Abstract

Here, we develop a flexible microrobot enhancing the steerability of a conventional guidewire. To improve steerability, a microrobot is attached to the tip of the guidewire and guided using an external magnetic field generated by an electromagnetic coil system. The flexible microrobot is fabricated via replica-molding and features a body made of polydimethylsiloxane (PDMS) and a single permanent magnet. As the robot is made of a deformable material, it can be steered using a low-intensity external magnetic field; the robot can potentially be guided into the coronary artery. To study steering performance, we employed mathematical modeling and a finite element model (FEM), and performed experiments under various magnetic fields. We found that a mathematical model using the Euler-Bernoulli beam could not precisely calculate the deformation angles. The FEM more accurately estimated those angles. The deformation angle can be controlled from 0 to 80° at a magnetic field intensity of 15 mT. The trackability at angles of 45 and 80° of the guidewire-based microrobot was confirmed in vitro using a two-dimensional blood vessel phantom.

A Learnt Approach for the Design of Magnetically Actuated Shape Forming Soft Tentacle Robots

“…where δ is beam deflection, E is elastic modulus, L is length and d is diameter. As in [29], given invariant geometric and material properties, (3) offers a linear correlation between δ and B 2 . To simulate the system, FEMs were constructed under the plane strain assumption in two dimensions in COMSOL multiphysics suite v5.4 (COMSOL AB, Stockholm, Sweden).…”

Real-Time Tracking of Guidewire Robot Tips Using Deep Convolutional Neural Networks on Successive Localized Frames

“…For evaluation of the proposed method, we acquired 11 videos consisting a total of 11,884 frames collected from the DGIST-ETH Microrobot Research Center (DEMRC) using a VZM 600i Zoom Imaging Lens (Edmund Optics Inc., USA) linked to a camera (Grasshopper; Point Gray Research, Inc., Canada). The video sequences contain the guidewire moving in different directions with respect to the changes of magnetic fields in eight coils of the robotic system [9]. Moreover, the dataset has multiple types of guidewire robots with cluttered backgrounds and fast motion captured from top views (see Fig.…”

“…In this paper, a novel method is proposed to reliably track the robot tip through image analysis in video sequences captured by an optical zoom camera. Ultimately, the position of the micro robot guidewire tip should be tracked in X-ray images, but guidewire tip tracking in video is also important especially in the system development stage to assess whether the control system works properly [8], [9]. Moreover, given the difficulty of X-ray data acquisition for developing catheter tracking algorithms, we first perform tracking studies in camera images that are easy to acquire with the intention of extending the approach to X-ray images.…”

Development and Verification of Mechanism for Enhancement of Steering Angle and Active Locomotion for Magnetic Micro Active-Guidewire

“…Choi et al, introduced a magnetically actuated flexible microrobot (with a magnet diameter and length of 0.4 mm and 0.8 mm, respectively) to improve the steerability of a guidewire. The guidewire was driven by a 15mT field, and generated a steering angle of up to 80 • in a dc magnetic field [27]. Jeon et al developed a magnetically controlled soft microrobot using two permanent magnets with PDMS for steering a guidewire [28].…”