Precise Model-Free Spline-Based Approach for Magnetic Field Mapping

Ongaro, Federico; Heunis, Christoff M.; Misra, Sarthak

doi:10.1109/lmag.2018.2882506

Cited by 11 publications

(8 citation statements)

References 27 publications

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“…4) Laplacian Constrained 3D B-Spline Interpolation (SPL-LPL): In [21], a constrained version of SPL-3D was introduced, such that the divergence and curl of the interpolated magnetic field was zero at points on a separate e × f × g grid. We call this method SPL-LPL.…”

Section: A Structured Grid Methodsmentioning

confidence: 99%

“…In [17], [18], and [19], field data was interpolated with trilinear interpolation, and with tricubic interpolation in [20]. B-Spline interpolation of the fields was performed in [21]. In [8], the magnetic field generated by an external permanent magnet was modeled using modal-basis functions using data from FEM simulation.…”

Section: Interpolation Of Magnetic Field Datamentioning

confidence: 99%

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Modeling Electromagnetic Navigation Systems

et al. 2021

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Remote magnetic navigation is used for the manipulation of untethered micro and nanorobots, as well as tethered magnetic surgical tools for minimally invasive medicine. Mathematical modeling of the magnetic fields generated by magnetic navigation systems is a fundamental task in the control of such tools for biomedical applications. We describe and compare several existing and newly developed methods for representations of continuous magnetic fields using interpolation in the context of remote magnetic navigation. Clinical-scale electromagnetic navigation systems feature nonlinear magnetization and magnetization interactions between electromagnets, which renders accurate magnetic field modeling challenging. We first introduce a method that can adapt existing linear models to correct for nonlinear magnetization, with similar performance to the current state-of-the-art nonlinear model. Furthermore, we present a method based on convolutional neural networks that is able to improve on the state-of-the-art method by a factor of 5.4.

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Section: A Structured Grid Methodsmentioning

confidence: 99%

Section: Interpolation Of Magnetic Field Datamentioning

confidence: 99%

Modeling Electromagnetic Navigation Systems

et al. 2021

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“…Finally, the controller outputs forces that are mapped into currents at the electromagnets using a force-current map. As the setup is overactuated, we select a map that aims at minimizing the Frobenius norm of the third-order tensor collecting the Hessian matrices of each component of the field [10,21]. This choice minimizes the spacial variation of the electromagnetic gradient, and consequently, of the electromantic force (3).…”

Section: Methodsmentioning

confidence: 99%

A Contactless and Biocompatible Approach for 3D Active Microrobotic Targeted Drug Delivery

et al. 2019

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As robotic tools are becoming a fundamental part of present day surgical interventions, microrobotic surgery is steadily approaching clinically-relevant scenarios. In particular, minimally invasive microrobotic targeted drug deliveries are reaching the grasp of the current state-of-the-art technology. However, clinically-relevant issues, such as lack of biocompatibility and dexterity, complicate the clinical application of the results obtained in controlled environments. Consequently, in this work we present a proof-of-concept fully contactless and biocompatible approach for active targeted delivery of a drug-model. In order to achieve full biocompatiblity and contacless actuation, magnetic fields are used for motion control, ultrasound is used for imaging, and induction heating is used for active drug-model release. The presented system is validated in a three-dimensional phantom of human vessels, performing ten trials that mimic targeted drug delivery using a drug-coated microrobot. The system is capable of closed-loop motion control with average velocity and positioning error of 0.3 mm/s and 0.4 mm, respectively. Overall, our findings suggest that the presented approach could augment the current capabilities of microrobotic tools, helping the development of clinically-relevant approaches for active in-vivo targeted drug delivery.

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“…Precise magnetic field information from each field source is required for actuation. Previously used approaches model the magnetic field either using an arbitrary function and fit unknown coefficients with least squares optimization [12,15], or use a first-order dipole approximation [5]. The former approach does not typically enforce constraints on the spatial gradients of the magnetic field, and the latter ignores higher order field effects that are more prominent closer to the field source [16].…”

Section: Introductionmentioning

confidence: 99%

Multi-Point Orientation Control of Discretely-Magnetized Continuum Manipulators

Richter

Venkiteswaran

Misra

2021

IEEE Robot. Autom. Lett.

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In the past decade, remote actuation through magnetic fields has been used for position and orientation control of continuum manipulators (CMs) with a single magnet at the distal tip. By leveraging multiple points of actuation along the length of the CM it is possible to achieve increasingly complex shapes, which could be of interest in complex navigation tasks, for example, in minimally invasive surgery. In this study we present an approach for multi-point orientation control of discretely magnetized CMs. The approach is demonstrated with a manipulator that contains two permanent magnets, which are each actuated inside a non-homogeneous magnetic field. We formulate an accurate field model that conforms to Maxwell's equations and apply this to the available actuation system. Furthermore, Cosserat rod theory is used to model the manipulator deformation under external wrenches, and is utilized to numerically compute a Jacobian necessary to calculate the actuation inputs. During experiments, a stereo vision setup is used for manipulator shape feedback. Target orientations are manually provided as input to show independent orientation control of the two permanent magnets. Additionally, simulations with an extended virtual clone of the electromagnetic system are performed to show the capability of achieving more complex manipulator shapes. In both scenarios, it is observed that the algorithm is able to independently control the orientation of two interconnected magnets in a non-uniform magnetic field.

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Precise Model-Free Spline-Based Approach for Magnetic Field Mapping

Cited by 11 publications

References 27 publications

Modeling Electromagnetic Navigation Systems

Modeling Electromagnetic Navigation Systems

A Contactless and Biocompatible Approach for 3D Active Microrobotic Targeted Drug Delivery

Multi-Point Orientation Control of Discretely-Magnetized Continuum Manipulators

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