Introducing BigMag — A novel system for 3D magnetic actuation of flexible surgical manipulators

Abstract

Magnetic interaction can be utilized for remote actuation of surgical manipulators. However, platforms currently available for that purpose have limited workspaces, inadequate field strength or very low bandwidth of the electrical subsystem. In this paper, we present BigMag, a novel platform capable of magnetic steering of continuum manipulators for medical purposes. BigMag comprises of 6 mobile coils and is capable of generating the fields of at least 40 mT in any direction at every point of its workspace. Moreover, we introduce a mathematical model for 3D mobile coil arrays. Each coil is modelled using finite element data adjusted by measurementbased correction, (a maximum observed mean error between the model and the prediction of 3.36 ± 5.62%). The model for a full system is validated in two tasks. In the first task, the system executes a prescribed rotating field (mean error between the model and measurement of 7.51% and minimum R 2 of 0.964). The second task tests the estimation of the field for known 3D trajectories (minimum R 2 of 0.967). The investigation concludes with a demonstration of BigMag capabilities in actuation of magnetic catheters in confined spaces usinguser-controlled steering.

Flexible Instruments for Endovascular Interventions: Improved Magnetic Steering, Actuation, and Image-Guided Surgical Instruments

“…These fields cover interventions such as peripheral and cardiac procedures, including angiography, angioplasty, and ablation [70]. Clinical trials have reported beneficial effects in the use of steerable catheters in interventional cardiology, while most studies concern advances in cardiac catheter technology and interventions [24], [30], [70], [73], with a main focus on passive magnetic actuation systems.…”

“…Permanent magnets Electromagnets [18], [30], [31], [36], [38] • Can generate high deflection forces.…”

“…This ferromagnetic material is widely utilized in catheter designs because it has strong magnetization, making it an excellent candidate for steering catheter tips [29]. Studies using both electromagnets [30], [31] and permanent magnets [32] for passive actuation have utilized Nd-Fe-B magnets in their catheter models, although the majority has implemented single magnetic components. Recently, Edelmann et al [33] demonstrated the modeling of different catheter geometries with multiple magnetic components and various boundary constraints.…”

“…Problems like the accuracy of closed-loop control strategies [83], 2-D-US tracking algorithm inaccuracies and 2-D plane visualization limitations [36], small operational workspaces [84], and magnetic field estimation inaccuracies [30] seem to arise frequently. Studies that take place in stationary environments tend to simplify complex scenarios; however, additional tracking uncertainties may occur because of the reduced visibility of the catheter [85].…”

Grasping Using Magnetically-Actuated Tentacle Catheter: A Proof-of-Concept Study

“…This force strengthens the grasp and allows for object manipulation. We test our design experimentally, using BigMag for magnetic actuation [17]. We employ a force sensor to quantify the strength of the grasp and compare the results with a finite element simulation.…”