Design Of A Master-slave Controlling System For Endovascular Intervention Robot With Variable Stiffness And Force Feedback

In the past decades,cardiovascular disease(CVD)has been the major cause of death in our country.Robot-assisted endovascular intervention surgery has attracted much interest recently.However,available commercial applications of endovascular intervention robots are limited by their high costs,large size,and long-time installation.Besides,few researchers have focused on variable stiffness and force feedback.Therefore,this paper illustrated the mechanism design,controlling program and the realization of variable stiffness and force feedback function of the endovascular intervention robot.Finally,a prototype was fabricated and several experiments were conducted.The detailed contents of this paper are presented as follows:Firstly,to achieve variable stiffness,three catheter designs were presented which enable the user to control the stiffness of catheter by heating/cooling.These catheters can improve intervention efficiency while staying in compact sizes.Then,two driving mechanisms were proposed that have two degrees of freedom to deliver the catheter.With the customized program,the driving mechanisms can be controlled remotely.Additionally,a manipulator was designed and fabricated.Its operating mode is similar to the natural motion of surgeons.Afterward,the Fiber Bragg Grating(FBG)sensors were adopted to construct a parallel sensor module.The principle of FBG sensors is briefly described.The sensor module has been integrated into the tip of the catheter so that it can measure the contact force between the catheter and the vessel wall in real-time.Signals acquired by the FBG sensor module could be transmitted to the brakes that integrated into the manipulator,which makes the force feedback function possible.Finally,experimental results show that the driving mechanism is able to deliver linear and rotational motions.The feasibility of force sensing/feedback is proved.The designed catheter can change its stiffness partially,and the stiffness of the catheter is remarkably increased in the rigid state.The fabricated prototype has been validated with a vascular phantom,demonstrating the potential clinical value of the system.The proposed system provides important insights into the design of compact intervention robot incorporating effective variable stiffness mechanism and real-time force sensing for intraoperative endovascular intervention.