Closed-Loop Control of a Helmholtz Coil System for Accurate Actuation of Magnetic Microrobot Swarms

Jiang, Jialin; Yang, Lidong; Zhang, Li

doi:10.1109/lra.2021.3052394

Cited by 32 publications

(17 citation statements)

References 33 publications

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“…Magnetic resonance navigation (MRN) of microrobots has so far relied on either external gradients coils, 4 small animal 7T scanner, 6 Helmholtz Coil System 12 and rotating magnetic field 1 to either compensate for the lower gradients amplitude found in clinical MRI (~43mT/m) or to find an alternative. Our results show that MRN is still possible using a 3T clinical MRI if all the forces applied on the microrobots are considered in the navigation: friction, gravity and buoyancy forces, combined MRI gradients amplitude and thrust force from the blood flow.…”

Section: Discussionmentioning

confidence: 99%

“…2 Lastly, a closed-loop control of a Helmholtz coil system for actuation of magnetic microrobot swarms was proposed to form and steer aggregates of nanoparticles. 12 Since the magnetic force increases at a cubic rate of the bead's radius 29 , a single magnetic microparticle is difficult to steer. Forming aggregate with known numbers of particles was first introduced by Li et al 3 to optimize steering and increase therapeutic loads per bolus, without the need of external coils.…”

Section: Introductionmentioning

confidence: 99%

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Navigation of Microrobots by MRI: Impact of Gravitational, Friction and Thrust Forces on Steering Success

Tous

Dimov

et al. 2021

Ann Biomed Eng

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Introduction Magnetic resonance navigation (MRN) uses MRI gradients to steer magnetic drug-eluting beads (MDEBs) across vascular bifurcations. We aim to experimentally verify our theoretical forces balance model (gravitational, thrust, friction, buoyant and gradient steering forces) to improve the MRN targeted success rate. Method A single-bifurcation phantom (3 mm inner diameter) made of poly-vinyl alcohol was connected to a cardiac pump at 0.8 mL/s, 60 beats/minutes with a glycerol solution to reproduce the viscosity of blood. MDEB aggregates (25 6 6 particles, 200 lm) were released into the main branch through a 5F catheter. The phantom was tilted horizontally from 2 10 to +25 to evaluate the MRN performance. Results The gravitational force was equivalent to 71.85 mT/m in a 3T MRI. The gradient duration and amplitude had a power relationship (amplitude=78.717 ðdurationÞ À0:525 ). It was possible, in 15 elevated vascular branches, to steer 87% of injected aggregates if two MRI gradients are simultaneously activated (G x = +26.5 mT/m, G y = +18 mT/m for 57% duty cycle), the flow velocity was minimized to 8 cm/s and a residual pulsatile flow to minimize the force of friction. Conclusion Our experimental model can determine the maximum elevation angle MRN can perform in a single-bifurcation phantom simulating in vivo conditions.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Navigation of Microrobots by MRI: Impact of Gravitational, Friction and Thrust Forces on Steering Success

Tous

Dimov

et al. 2021

Ann Biomed Eng

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“…Practically, a microrobot is a complicated system with high nonlinearity and uncertainty. The unmodelled dynamics, Brownian motion, [109][110][111] external fluid force, [101,112] and inaccuracy of the actuation system [113] all could distort the controllability of microrobots, making classic linear controllers like PID inadequate for some control tasks. Thus, more advanced nonlinear control strategies need to be proposed.…”

Section: Nonlinear Controlmentioning

confidence: 99%

Control and Autonomy of Microrobots: Recent Progress and Perspective

Jiang

Yang

Ferreira

et al. 2022

Advanced Intelligent Systems

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After decades of development, microrobots have exhibited great application potential in the biomedical field, such as minimally invasive surgery, drug delivery, and bio‐sensing. Compared with conventional medical robotic systems, microrobots may be capable of reaching more narrow and vulnerable regions in the human body with minimal damage. However, limited by the small scale of microrobots, microprocessors, power supplies, and sensors can hardly be integrated on‐board. Thus, new strategies for the actuation and feedback for microrobots need to be explored. Furthermore, the open‐loop control method accomplished by operators may lack accuracy, and long‐duration operation could bring a severe physical challenge in many applications. Consequently, the automatic control of microrobots with the aid of control theories is developed to improve the control efficiency and precision. To further promote the automation level of microrobots, machine learning algorithms are expected to provide a solution to let microrobots adapt to more dynamic environments and undertake more complex medical tasks. Herein, a systematic introduction of the manipulation of microrobots from open‐loop to closed‐loop control is given in this review. It is envisioned that microrobots will play an important role in future biomedical applications.

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“…These magnetic swarms can achieve controllable shifting and task actuation in different shapes and sizes under different parameters. [ 144,145 ] It also permits reversible shape transformation and effective recovery from various biological fluids, which is proper for cargo transport and biofilm removal in different physiological environments. In 2017, Geilich et al.…”

Section: Advanced Micro/nanorobotic Strategy For Biofilm Removalmentioning

confidence: 99%

Micro‐/Nanorobots in Antimicrobial Applications: Recent Progress, Challenges, and Opportunities

Zhang

Wang

Chan

et al. 2021

Adv Healthcare Materials

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The evolution of drug‐resistant pathogenic bacteria remains one of the most urgent threats to public health worldwide. Even worse, the bacterial cells commonly form biofilms through aggregation and adhesion, preventing antibiotic penetration and resisting environmental stress. Moreover, biofilms tend to grow in some hard‐to‐reach regions, bringing difficulty for antibiotic delivery at the infected site. The drug‐resistant pathogenic bacteria and intractable biofilm give rise to chronic and recurrent infections, exacerbating the challenge in combating bacterial infections. Micro/nanorobots (MNRs) are capable of active cargo delivery, targeted treatment with high precision, and motion‐assisted mechanical force, which enable transport and enhance penetration of antibacterial agents into the targeted site, thus showing great promise in emerging as an attractive alternative to conventional antibacterial therapies. This review summarizes the recent advances in micro‐/nanorobots for antibacterial applications, with emphasis on those novel strategies for drug‐resistance bacterium and stubborn biofilm infections. Insights on the future development of MNRs with good functionality and biosafety offer promising approaches to address infections in the clinic setting.

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Closed-Loop Control of a Helmholtz Coil System for Accurate Actuation of Magnetic Microrobot Swarms

Cited by 32 publications

References 33 publications

Navigation of Microrobots by MRI: Impact of Gravitational, Friction and Thrust Forces on Steering Success

Navigation of Microrobots by MRI: Impact of Gravitational, Friction and Thrust Forces on Steering Success

Control and Autonomy of Microrobots: Recent Progress and Perspective

Micro‐/Nanorobots in Antimicrobial Applications: Recent Progress, Challenges, and Opportunities

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