Scaled-up helical nanobelt modeling and simulation at low reynolds numbers

IEEE/ASME Trans. Mechatron.

et al. 2014

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Micro and nanorobots capable of controlled propulsion at low Reynolds number are foreseen to change many aspects of medicine by enabling targeted diagnosis and therapy, and minimally invasive surgery. Several kinds of helical swimmers with different heads actuated by a rotating magnetic field have been proposed in prior works. Beyond these proofs of concepts, this paper aims to obtain an optimized design of helical swimmers adapted to low Reynolds numbers. For this, we designed an experimental setup and scaled-up helical nanobelt swimmers with different head and tail coatings to compare their rotational propulsion characteristics. We found in this paper that the head shape of a helical swimmer does not influence the shape of the rotational propulsion characteristics curve, but it influences the cutoff frequency values. The rotational propulsion characteristics of helical swimmers with a magnetic head or a magnetic tail are different. The helical swimmers with uniformly coated magnetic tails do not show a cutoff frequency whereas the ones with a magnetic head exhibit a saturation of frequency.

“…The parameters (a, b) are thus the solution to the linear system formed by the last two equations (14) and (15).…”

Section: A Propulsion Matrix Identificationmentioning

confidence: 99%

Modeling and Swimming Property Characterizations of Scaled-Up Helical Microswimmers

Hwang²,

IEEE/ASME Trans. Mechatron.

et al. 2014

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“…The category named SHN10-magTail includes SHN10s with their first pitch (i.e. a 1-full-turn portion of the helix) covered with NdFeB permanent magnets (5 mm × 1.5 mm × 1 mm), since as described in [15], the SHN10s with one magnetic pitch are more advantageous than those with full magnetic pitch. In this category, SHN10s have different head shapes : without a head, with a cylindrical head, spherical head and square head, as shown in Fig.…”

Section: A Scaled-up Helical Swimmers With Different Headsmentioning

confidence: 99%

The rotational propulsion characteristics of scaled-up helical microswimmers with different heads and magnetic positioning

Hwang²,

2013 IEEE/ASME International Conference on Advanced Intelligent Mechatronics

et al. 2013

Self Cite

Micro and nanorobots capable of controlled propulsion at low Reynolds number are foreseen to change many aspects of medicine by enabling targeted diagnosis and therapy, and minimally invasive surgery. Several kinds of helical swimmers with different heads actuated by a rotating magnetic field have been proposed in prior works. Beyond these proofs of concepts, this paper aims to study behaviours of helical swimmers with different head and magnetic positing adapted to low Reynolds number liquids. For this, we designed an experimental setup and scaled-up helical nanobelt swimmers with different heads and tail coatings to compare their rotational propulsion characteristics. We found in this paper that the head shape of a helical swimmer does not influence on the shape of the rotational propulsion characteristics curve, but it influences on the values of the cutoff frequency. The rotational propulsion characteristics of helical swimmers with a magnetic head or a magnetic tail are much different. The helical swimmer with uniformly coated magnetic tail does not show a cutoff frequency but a saturation of frequency.

“…Compared to our previous works [20], [21], we designed a new helical swimmer and developed Helmholtz coils for uniform rotating magnetic field generation in Section III. The real-time visual tracking of the helical swimmer's axis is also introduced in this section.…”

Section: Introductionmentioning

confidence: 99%

Characterization of three-dimensional steering for helical swimmers

Hwang²,

2014 IEEE International Conference on Robotics and Automation (ICRA)

et al. 2014

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Abstract-Helical microswimmers capable of propulsion at low Reynolds numbers have been proposed for many applications. However, closed-loop controlled helical swimmers are still challenging because of the limits of optical tracking, and a lack of control parameters lying on the swimming characteristics of both linear propulsion and steering. Although the linear propulsion characteristics of helical swimmers were extensively studied, the steering characteristics have not yet been clearly shown. Helical microswimmers are efficient in propulsion, whereas their high surface-to-volume ratio limits the steering performances. In this paper, we characterized both the direction and inclination steering using a real-time visual tracking of orientation. The direction steering efficiency could be increased in terms of response time with a higher inclination angle both in floating conditions and on a sticky substrate. We thus developed a 3D steering strategy by combining direction and inclination steering to improve the steering performance. We further expect that the characterization of steering performance can contribute to defining the control parameters for future closed-loop control.