MILiMAC: Flexible Catheter with Miniaturized Electromagnets as a Small-Footprint System for Microrobotic Tasks

Advancements in medical microrobotics have given rise to an abundance of agents capable of localised interaction with human body in small scales. Nevertheless, clinically-relevant applications of this technology are still limited by the auxiliary infrastructure required for actuation of micro-agents. In this letter, we approach this challenge. Using finite-element analysis, we show that miniaturization of electromagnets can be used to create systems capable of providing magnetic forces adequate for micro-agent steering, while retaining small footprint and power consumption. We use these observations to create MILiMAC (Microrobotic Infrastructure Loaded into Magnetically-Actuated Catheter). MILiMAC is a flexible catheter employing three miniaturized electromagnets to provide localized magnetic actuation at the deeply-seated microsurgery site. We test our approach in a proof-of-concept study deploying MILiMAC inside a test platform to deliver and steer a 600 [\boldsymbol{\mu }m] ferromagnetic microbead. The bead is steered along a set of user-defined trajectories using closed-loop position control. Across all trajectories the best performance metrics are the mean error of 0.41 [mm] and the steady-state error of 0.27 [mm].