Iterative Jacobian-Based Inverse Kinematics and Open-Loop Control of an MRI-Guided Magnetically Actuated Steerable Catheter System

Abstract

This paper presents an iterative Jacobian-based inverse kinematics method for an MRI-guided magnetically-actuated steerable intravascular catheter system. The catheter is directly actuated by magnetic torques generated on a set of current-carrying micro-coils embedded on the catheter tip, by the magnetic field of the magnetic resonance imaging (MRI) scanner. The Jacobian matrix relating changes of the currents through the coils to changes of the tip position is derived using a three dimensional kinematic model of the catheter deflection. The inverse kinematics is numerically computed by iteratively applying the inverse of the Jacobian matrix. The damped least square method is implemented to avoid numerical instability issues that exist during the computation of the inverse of the Jacobian matrix. The performance of the proposed inverse kinematics approach is validated using a prototype of the robotic catheter by comparing the actual trajectories of the catheter tip obtained via open-loop control with the desired trajectories. The results of reproducibility and accuracy evaluations demonstrate that the proposed Jacobian-based inverse kinematics method can be used to actuate the catheter in open-loop to successfully perform complex ablation trajectories required in atrial fibrillation ablation procedures. This study paves the way for effective and accurate closed-loop control of the robotic catheter with real-time feedback from MRI guidance in subsequent research.

Magnetic Resonance Imaging System–Driven Medical Robotics

“…For Lorentz torque–based actuation methods, typically the Lorentz coil is firmly attached to a flexible body to induce a local torque where it is located. Such a torque is used to deform the flexible body to control a catheter tip orientation or create a propulsion force in a fluid …”

“…For Lorentz torque–based actuation methods, typically the Lorentz coil is firmly attached to a flexible body to induce a local torque where it is located. Such a given torque is used to deform the flexible body to control the catheter tip orientation . In terms of catheter coil design, generally one or more sets of coils, referred to as “saddle” or “axial” depending upon the design, are wound, 3D‐printed, or cut using laser lithography at the tip of the catheter .…”

“…This issue was resolved later by Hetts et al by regulating the current to less than 300 mA with less than 1 min activation times and using a saline coolant under a 1.5 T MR scanner . Liu et al developed and validated a 3D kinematic model and control of 3 F MRI‐steerable catheters within 3 T MR scanners designed specifically for accessing the workspace of the heart for atrial fibrillation . This model was later improved with a design optimization of an MRI‐driven catheter given more than one coil set …”

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

“…Similarly, Liu et al [25] presented a catheter embedded with a set of current-carrying microcoils that was actuated by MR. In their latest study, they presented a prototype with a single axial coil and two orthogonal coils to allow for control of the 3-D deflection.…”

Iteratively Successive Projection: A Novel Continuous Approach for the Task-Based Control of Redundant Robots

“…However, the joint space method is limited for the cases with subtasks in the task space, such as obstacle avoidance and visual servoing. Due to the limitation of the control methods in the joint space, the control approaches in task space have been proposed [2]- [5]. In the task-based approach, the gradient project method (GPM) was first adopted to achieve joint-limit avoidance task in [6], and obstacle avoidance task in [7].…”