A Novel Dexterous Steerable Catheter Robot System: Design, Modeling and Evaluation

Vascular interventional surgery (VIS) robots still face limitations in enhancing treatment quality. The primary challenges come from the accurate morphology control and miniaturization of the distal instruments. To address these issues, a novel 4 degrees of freedom steerable catheter robotic system is developed. The catheter is composed of two segments continua connected in series. By actuating the two segments independently, the distal end of the catheter has both position and wide-range orientation control capabilities. To accurately estimate the continuum deformation, an improved tendon tension propagation model considering the path friction is proposed. Then a continuum morphology estimation model is derived cell by cell based on the chain beam assumption. Based on the estimation model, the kinetostatic model is established and a model-based nonlinear numerical solution method is developed to obtain the inverse solution of the actuation space. Experimental results demonstrate that the improved tendon tension propagation model reduces the control errors in position and orientation by 45.6% and 57.6% respectively compared with the simplified model. Additionally, the dexterity and operability of the robotic system are demonstrated by 4 navigation experiments.