New kinematic multi-section model for catheter contact force estimation and steering

Contact force play is a significant role in success of the cardiac ablation. However, it is still challenging to estimate contact force when a catheter is under large bending and multiple contacts. This paper develops a new multi-section static model of the tendon-driven catheters for both real-time intrinsic force sensing and interaction control. The model allows estimating the catheter shape by the external force at arbitrary location. Also, an algorithm is developed for the contact force estimation using the shape estimation with the catheter end-position tracking and tension feedback. In this study, we validated the contact force and shape estimation using a robotic platform, which steers a catheter consisting of 4 tendons with tension feedback. The shape estimation results show that the model can accurately predict the catheter shape; the position difference between measured and estimated was 2.5mm. The results of the contact force estimation show that 3-dimensional contact forces can be estimated accurately using the proposed method. The magnitude of contact force error was 0.0117N with 350Hz update rate.