Remote Magnetic Levitation Using Reduced Attitude Control and Parametric Field Models

IEEE Robotics and Automation Letters · 2026-05-11

Electromagnetic navigation systems (eMNS) are increasingly used in minimally invasive procedures such as endovascular interventions and targeted drug delivery due to their ability to generate fast and precise magnetic fields. In this paper, we utilize the OctoMag and a custom 13-coil eMNS to achieve remote levitation and control of multiple rigid bodies across large air gaps, showcasing the dynamic capabilities of such systems. A compact parametric analytical model maps coil currents to the forces and torques acting on the levitating object, eliminating the need for computationally expensive simulations or lookup tables and establishing a levitator- and platform-agnostic control framework. Translational motion is stabilized using linear quadratic regulators. A nonlinear time-invariant controller is used to regulate the reduced attitude accounting for the inherent uncontrollability of rotations about the dipole axis and stabilizing the full five degrees of freedom controllable pose subspace. We analyze key design limitations and evaluate the approach through trajectory tracking experiments across different objects and actuation platforms. Notably, our proposed controller demonstrates superiority over an equivalent baseline PID formulation, reliably tracking large spatial angles up to 65<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula>. This work demonstrates the dynamic capabilities and potential of feedback control in electromagnetic navigation, which is likely to open up new medical applications.

Analysis of the Navigation of Magnetic Microrobots through Cerebral Bifurcations for Targeted Drug Delivery

Advanced Intelligent Systems · 2025-06-22 · 4 citations

Local administration of thrombolytics in ischemic stroke could accelerate clot lysis and the ensuing reperfusion while minimizing the side effects of systemic administration. Medical microrobots could be injected into the bloodstream and magnetically navigated to the clot for administering the drugs directly to the target. The magnetic manipulation that is required to navigate medical microrobots depends on various parameters such as the microrobots size, the blood velocity, and the imposed magnetic field gradients. Numerical simulation was used to study the motion of magnetically controlled microrobots flowing through representative cerebral bifurcations, for predicting the magnetic gradients required to navigate the microrobots from the injection point until the target location. Upon thorough validation of the model against several independent analytical and experimental results, the model was used to generate maps and predictive equations providing quantitative information on the required magnetic gradients, for different scenarios. The developed maps and predictive equations are crucial to inform the design, operation, and optimization of magnetic navigation systems for healthcare applications.

Clinically ready magnetic microrobots for targeted therapies

Science · 2025-11-13 · 36 citations

Systemic drug administration often causes off-target effects, limiting the efficacy of advanced therapies. Targeted drug delivery approaches increase local drug concentrations at the diseased site while minimizing systemic drug exposure. We present a magnetically guided microrobotic drug delivery platform capable of precise navigation under physiological conditions. This platform integrates a clinical electromagnetic navigation system, a custom-designed release catheter, and a dissolvable capsule for accurate therapeutic delivery. In vitro tests showed precise navigation in human vasculature models, and in vivo experiments confirmed tracking under fluoroscopy and successful navigation in large animal models. The microrobot balances magnetic material concentration, contrast agent loading, and therapeutic drug capacity, offering a promising solution for precise targeted drug delivery.

A Covalently Bonded Exchange Coupled Nanomagnet‐Based Hydrogel Composite for Microrobotic Applications

Advanced Intelligent Systems · 2025-05-29

The last decade has witnessed rapid progress in the development of soft microrobots for biomedical applications, largely powered by the incorporation of new materials in their design to address various challenges. Herein, a unique magnetic nanoparticle‐hydrogel composite designed for microrobot applications is introduced. This composite comprises iron platinum‐zinc ferrite nanoparticles whose magnetic properties are enhanced by magnetic exchange‐coupling behavior. The introduction of zinc ferrite further allows for grafting alkyne‐bearing ligands on the nanoparticles, enabling them to be covalently immobilized within the hydrogel framework via azide‐alkyne cycloaddition, thereby improving the composite's stability. Using a template‐assisted 3D fabrication technique, the feasibility of using this composite for soft microrobots is demonstrated. Hence, one can assume this straightforward procedure to be easily adapted to other material systems, facilitating the creation of more customized soft microrobots.

A roadmap for next-generation nanomotors

Nature Nanotechnology · 2025-08-01 · 26 citations

Design and Optimization of Remagnetization Actuators

IEEE Transactions on Magnetics · 2025-07-02

Magnetization programming is a promising approach in the field of robotic magnetic navigation in which magnetized devices are manipulated using externally generated magnetic fields. This work explores the design and optimization of remagnetization actuators to dynamically reprogram the magnetization of the devices to be manipulated. The influence of the material and geometry of the magnet to be programmed and of the remagnetization circuit parameters on the performance of the programming are investigated. Performance assessment focuses on maximizing the achievable torque on the magnet and optimizing the dynamics and efficiency of the remagnetization. The key findings of this study are that AlNiCo 9 magnets can deliver superior torque compared to AlNiCo 5, and that using hollow instead of solid cylindrical magnets can improve the remagnetization process with only a limited reduction in its maximum achievable torque. These findings provide an important foundation for advancing the performance and reliability of remagnetization actuators in magnetic control systems.

Orthogonal Pulse-Width-Modulation for Combined Electromagnetic Actuation and Localization

IEEE Robotics and Automation Letters · 2025-05-08 · 2 citations

Electromagnetic Navigation Systems can be used to remotely guide medical devices such as magnetic catheters or guidewires, holding potential in a variety of minimally invasive surgical applications. This paper introduces a method to simultaneously actuate and localize a tethered magnetic device with embedded sensor pickup coils using a single system. Six-degree-of-freedom localization is achieved by driving the electromagnets of the Electromagnetic Navigation System with mutually orthogonal pulse-width-modulated voltages of different frequencies. The method is demonstrated using a human-scale system composed of three electromagnets to actuate and localize a magnetic catheter prototype with pickup coils embedded at its tip. In this case, the pose is estimated at a rate of 77 Hz, with a typical mean accuracy below 2 mm in position and 2<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> in orientation.

Technology Roadmap of Micro/Nanorobots

ACS Nano · 2025-06-27 · 68 citations

, the field of micro/nanorobots has evolved from science fiction to reality, with significant advancements in biomedical and environmental applications. Despite the rapid progress, the deployment of functional micro/nanorobots remains limited. This review of the technology roadmap identifies key challenges hindering their widespread use, focusing on propulsion mechanisms, fundamental theoretical aspects, collective behavior, material design, and embodied intelligence. We explore the current state of micro/nanorobot technology, with an emphasis on applications in biomedicine, environmental remediation, analytical sensing, and other industrial technological aspects. Additionally, we analyze issues related to scaling up production, commercialization, and regulatory frameworks that are crucial for transitioning from research to practical applications. We also emphasize the need for interdisciplinary collaboration to address both technical and nontechnical challenges, such as sustainability, ethics, and business considerations. Finally, we propose a roadmap for future research to accelerate the development of micro/nanorobots, positioning them as essential tools for addressing grand challenges and enhancing the quality of life.

Soft magnetic microrobots with remote sensing and communication capabilities

Nature Communications · 2025-11-25 · 4 citations

Remote communication in small-scale robotics offers a powerful way to enhance their capabilities, introducing options for state monitoring, multi-agent collaboration, and autonomous operation. Integrating common remote communication tools, such as antennas, into microrobots is challenging with conventional design and manufacturing techniques. We propose a concept that integrates shape-reconfigurable soft microrobots with flexible electronics, leveraging their elastic mechanical properties to enable remote communication. This approach, based on photolithography processes, is scalable and adaptable to various sensing applications. As a proof of concept, we present a microrobot, which integrates a thermoresponsive magnetic hydrogel, an anisotropic support structure, and a flexible dipole antenna into a cohesive three-layered design. The microrobot can morph from a helical shape at low-temperatures to a planar shape at high-temperatures. This shape transformation can be remotely detected by external radio communication receivers, enabling shape-state recognition and environmental temperature sensing. Furthermore, we show that the collective behavior of multiple microrobots enhances the recognition performance by amplifying the signal. The concept represents a significant advancement in co-engineering smart materials and flexible electronics, illustrating an approach of microrobotic embodied intelligence by integrating environmental monitoring, magnetic navigation, and remote signaling.

Strategies for Navigating Magnetic Microrobots in Neurovascular Networks: A Numerical Analysis

Small Science · 2025-07-25

First-line therapy for ischemic stroke relies on the systemic administration of thrombolytics for dissolving clots affecting brain perfusion. However, because conservative dosages are used to avoid off-target toxicity and side effects, the systemic route is often unable to deal with large clots in a timely manner. Targeted delivery of thrombolytics could be the solution if microrobots carrying the drugs could be navigated through the patient's neurovascular network to locally administer them directly to the clot. Herein, the steering of magnetic microrobots along a patient-specific neurovascular network is numerically studied, for optimizing the navigation of the microrobots to target vessels often obstructed in ischemic stroke. It is found that spatially constant magnetic gradients can be used to navigate the microrobots to the target vessels and describe various navigation strategies that can be used by health professionals to reach different positions in the vasculature. Equations are developed to predict the required magnetic gradients as a function of the microrobot diameter, which are key for the development of magnetic navigation systems that can autonomously navigate microrobots through neurovascular networks. These findings open exciting possibilities for exploring targeted drug delivery approaches in clinical settings.