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

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 measurement-based 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.