Session: 07-15-01: Dynamics and Control of Soft Structures
Paper Number: 145080
145080 - Bi-Directional Locomotion of Asymmetric Curved Soft Millirobot Under Magnetic Fields in Different Frequencies
Soft-Millirobots have been researched and tested throughout a plethora of different fields like biomedical, robotics, and engineering. Their small scale and exceptional flexibility provide them with unprecedented access to narrow and complex spaces, setting them apart from standard robotic models. However, the exploration of their potential for surface swimming has been comparatively overlooked.
In this paper, we demonstrate the bidirectional swimming locomotion of a curved soft millirobot under an alternating magnetic field at various frequencies, along with its characterization across different curvatures. The small-scale robot is made up of a clear polymer and a ferromagnetic particle that is used to help with the locomotion of the robot. The polymer's body is made up of a clear flexible polymer, while the head of the robot is composed of a mixture of clear polymer composite and ferromagnetic particles. The robots are about 4 mm in length, 1.5 mm in width, and 0.3 mm in thickness and the head of the robot is comprised of half of the overall length of the robot. To create a robot with a curved body, the robot is first placed into a hole within a non-magnetic aluminum bar. Once the robot is inside the hole, the aluminum bar is heated up on a hot plate at 200°C for 25 minutes. After cooling, the robot is magnetized along its major axis using a neodymium magnet within a magnetization apparatus.
To control the robot, it is positioned within a spacious, transparent plexiglass chamber filled with distilled water to minimize external interference from the wall. A three-dimensional Helmholtz coil setup generates time-varying magnetic fields following a triangular waveform, primarily along the z-axis, with frequencies ranging from 40 to 250 Hz. Employing a closed feedback loop, we control the trajectory of the curved soft millirobot, enabling it to navigate along a predetermined path at various speeds by adjusting the frequency of the alternating magnetic field within the specified range. The robots' locomotion is captured using a machine vision camera operating at 200 Hz and illuminated by a near-infrared LED (850 nm) over a field of view spanning nearly 40 mm by 40 mm.
Utilizing the alternating magnetic field, the curved millirobot exhibits two distinct modes of motion: moving forward and moving backward relative to its magnetic head. The robot advances when subjected to frequencies ranging from 40 Hz to nearly 150 Hz, reaching its maximum speed of around 90-100 Hz. In contrast, at higher frequencies between 151-250 Hz, the robot transitions into a backward motion with its speed peaking around 180-190 Hz. As for the curvature of the robots, the robots that have a higher curvature appear to exhibit faster speeds when compared to their lower curvature counterparts in both forward and backward locomotion. To demonstrate the controllability of the curved soft millirobot, we have successfully executed closed-feedback control along the pre-determined path inspired by reverse parking.
In this study, we have showcased the bidirectional swimming capabilities of curved soft millirobots under varying magnetic field frequencies, revealing their potential for precise navigation in complex environments. By adjusting the frequency of the alternating magnetic fields, we achieved controlled forward and backward movements, with the curvature of the robots playing a crucial role in their locomotion speed. This research not only advances our understanding of soft millirobots but also opens new avenues for their application in biomedical, robotics, and engineering fields, underscoring their versatility and potential for innovation.
Presenting Author: Dal Hyung Kim Kennesaw State University
Presenting Author Biography: Dr. Dal Hyung Kim is an Assistant Professor in the Department of Mechanical Engineering at Kennesaw State University. He earned his Ph.D. in Mechanical Engineering and Mechanics from Drexel University in 2013. Following his graduate study, Dr. Kim joined Rowland Institute at Harvard University as a postdoctoral researcher. In 2019, Dr. Kim joined Kennesaw State University as an assistant professor. His main research interests lie in Robotics, Optimized Control, Brain imaging, Biomedical Instrumentation, Microrobotics, and Optogenetics.
Authors:
Christophe Bulang Kennesaw State UniversityJessica Trinh Kennesaw State University
Jordan Scurry Kennesaw State University
Suk Joon Na Marshall University
Jungkyu Park Kennesaw State University
Dal Hyung Kim Kennesaw State University
Bi-Directional Locomotion of Asymmetric Curved Soft Millirobot Under Magnetic Fields in Different Frequencies
Paper Type
Technical Paper Publication