Free-Space Dynamic Modeling of an MRI-Actuated Robotic Catheter

In this article, we present the free-space dynamic modeling of a novel magnetic resonance imaging (MRI)-actuated robotic catheter. The MRI-actuated robotic catheter is modeled as a series of rigid and flexible segments, where the rigid segments are embedded with a set of current-carrying micro-coils. The robotic catheter is steered by controlling the currents passing through the actuators under the influence of the static magnetic field of the MRI-scanner. In this article, two discrete-time dynamic models of the MRI-actuated robotic catheter are presented and evaluated. The first model presented is a full-body Cosserat-rod-based dynamic model based on the dynamic Cosserat-rod theory, where the dynamic Cosserat-rod partial differential equations and the Euler–Lagrange equation are, respectively, used to derive the dynamic equations of the flexible segments and rigid segments. The second model presented is a hybrid Cosserat-rod-based dynamic model, where the dynamic equation of the rigid segments is derived using the Euler–Lagrange equation and the shape of the flexible segments is derived using the static Cosserat-rod theory. The proposed dynamic models are compared and experimentally validated using the 3-D positional trajectories collected from a catadioptric stereo tracking system.