A new microrobot manipulation technique with high precision (nano level) positional accuracy to move in a liquid environment with diamagnetic levitation is presented. Untethered manipulation of microrobots by means of externally applied magnetic forces has been emerging as a promising field of research, particularly due to its potential for medical and biological applications. The purpose of the presented method is to eliminate friction force between the surface of the substrate and microrobot. In an effort to achieve high accuracy motion, required magnetic force for the levitation of the microrobot was determined by finite element method (FEM) simulations in COMSOL (version 5.3, COMSOL Inc., Stockholm, Sweden) and verified by experimental results. According to position of the lifter magnet, the levitation height of the microrobot in the liquid was found analytically, and compared with the experimental results head-to-head. The stable working range of the microrobot is between 30 µm to 330 µm, and it was confirmed in both simulations and experimental results. It can follow the given trajectory with high accuracy (<1 µm error avg.) at varied speeds and levitation heights. Due to the nano-level positioning accuracy, desired locomotion can be achieved in pre-specified trajectories (sinusoidal or circular). During its locomotion, phase difference between lifter magnet and carrier magnet has been observed, and relation with drag force effect has been discussed. Without using strong electromagnets or bulky permanent magnets, our manipulation approach can move the microrobot in three dimensions in a liquid environment.
Abstract:In this article, we present a microrobot manipulation technique with high precision positional ability to move in a fluid environment with diamagnetic levitation. Untethered manipulation of microrobots by means of externally applied magnetic forces has been emerging as a promising field of research, particularly due to its potential for medical and biological applications. The decreased size of the robots makes them suitable for both in vitro applications such as sorting, moving, filtering micro particles (e.g. cells) within lab-on-a-chip platforms and in vivo applications such as minimallyinvasive surgeries or targeted drug delivery inside a human body. Precise (nano) positioning of the levitated microrobot on the pyrolytic graphite is demonstrated in the liquid. Positioning is achieved by the movement of a "lifter" magnet on the sensitive microstage. The suspended microrobot successfully tracked the identified roots. Our study is about controlling the microrobot suspended on the pyrolytic graphite with nano-precision via fixed lifting magnets. The purpose of the presented method is to eliminate the friction force between the surface of the substrate and the microrobot. Thus, high accuracy motion can be achieved.UDC Classification: 606 DOI: http://dx
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