Autonomous three-dimensional sensor-assisted hybrid force/position control for tendon-driven catheters

Minimally invasive active cardiac catheters enable the interventionalists to reach inside cardiac chambers and operate on the fast-moving heart without stopping it. The guidance of a catheter inside the cardiac chamber requires surgeon's high dexterity for accurate positioning of its tip and constant contact force implementation to the heart tissue. Besides, it exposes the physicians to long-term X-ray radiation. To address these issues, this paper introduces autonomous robot-assisted cardiac catheterization platform based on the model-based hybrid force/position control strategy. In this regard, Cosserat theory is adopted for modeling the distal shaft of steerable tendon-driven catheters. The proposed control framework applies force control, position tracking, while regarding the inherent catheter characteristics, actuation transferring from the catheter handle to distal shaft and force-displacement mappings of catheter-tissue interaction. To ensure the controller's performance, a stability analysis of the controller is conducted. The robotic system autonomously controls the contact force/position on the intracardiac chamber. The performance of system was validated with ex vivo experiments on three swine hearts. The platform controlled the force and position with the maximum average RMSE of 0.0204 N and 2.76 mm, respectively. Simulations and ex vivo experimental results verify the viability of autonomous robot-assisted system for clinical cardiac ablation.