A pseudo-rigid-body 3R model for a steerable ablation catheter

Over the past few decades, catheter-based cardiac ablation has been the first surgical option for treatment of arrhythmia. In order to have an effective ablation procedure, after positioning the catheter at the desired location inside the heart chamber, a consistent tip/tissue contact should be maintained during the whole procedure. With the goal of implementing hybrid force/position control of the catheter tip during the ablation procedure, this paper studies how the catheter tip deflects when forces are applied. A pseudo-rigid-body 3R model for the catheter tip is introduced. The model performance is evaluated through extensive experiments and it is shown that the proposed model can estimate the shape of the bending section of the ablation catheter if force information is available. This model does not require extensive knowledge of the catheter internal structure. Moreover, the well-established static equations are simple to understand and solve, making this model a convenient choice for developing a control system.