Research On A Cable-driven Interventional Catheter Surgery Robot System

With the continuous improvement of medical equipment and technique,as a new type of surgery robot,the interventional catheter surgery robot has got rapid development.The research of interventional catheter surgery robots is aimed to solve the problems of traditional interventional surgery,such as bad controllability,high difficulty,bad effect and massive radiation during the operation.By the system,catheter robot can take the place of surgeons to complete interventional catheter operations.A new complete interventional catheter surgery robot system is designed in this paper,which is composed of a mechanical system and a control system.This paper did a detailed research on structure design,robot system kinematics,static characteristics,driving cables analysis and master-slave control system.Through the study of traditional interventional catheter,a new cable-driven active catheter is designed combining the characteristics of cable-driven and SMA-driven catheters.The whole catheter consists of active catheters and common catheters.The position adjustment of the catheter is controlled by cables to make the catheter go forward and bend in vessels.To meet the demand of reconfigurability,a connecting component is designed to assembly and dismantle the tandem catheter easily on site.On the basis of the operating principle of the Tandem catheter,a catheter manipulating device is designed.The movement of the catheter is carried out by the cable driving module and linear pushing module.By the study of each module,the interventional catheter surgery robot system operating platform is established in this paper.In corresponding with the active catheter structure,the forward kinematics models for the single and multiple segments catheter units are established through D-H parameter method,and the workspace are solved.The single unit's inverse kinematics and Jacobian matrix are also solved in this paper.The relationship between driving force on cables and the catheter posture is analyzed basing on the study of static characteristics of the tandem catheter.The bending characteristic is analyzed on three models in which the catheter axis is simulated on the large deflection hypothesis,linear hypothesis and arc hypothesis.The equivalent bar model is established basing on the large deflection hypothesis.The deflection curve and the cable length expression are also solved.The whole framework of the master-slave control system for the catheter robot system is constructed in this paper,from the hardware layer and the controlling layer.The 3-dimension operating master device Falcon is used in the master-slave system.The master-slave mapping relations are established on the basis of spatial point-to-point model and incremental model to realize the following movement of slave device driven by PMAC controller and motors.The performance experiment platform is set up test the catheter prototype system.The final result shows that the interventional catheter surgery robot system is feasible and effective.