Design and analysis of feeder mechanism for buckling prevention in robotic catheterization

Abstract

Abstract In this study, a novel two-degree-of-freedom active-feeder mechanism with a disposable roller module for buckling prevention of the catheter tube was developed and analyzed. The buckling phenomenon occurs when the flexible part cannot withstand a compressive force. Buckling can be prevented using additional parts that support the long flexible part along the tube; however, these passive-type buckling-prevention mechanisms cannot improve transmissibility in a rotational motion. By contrast, the active-type mechanism can transmit both translational and rotational motion but has a bulky structure due to additional motors, which makes placing the mechanism near the patient difficult. Therefore, to solve the afore-mentioned issues, a compact and clinically practicable design is proposed. The proposed feeder mechanism was developed using two driving-shaft modules that enable simultaneous translational and rotational feeding with the minimum number of motors. Furthermore, to minimize the deformation of the tube and obtain sufficient grip force to replicate surgeons’ operation, the analysis was conducted based on contact mechanics. The maximum insertion force and rotating torque were estimated and verified using the measured static friction coefficient. In addition, we formulated an accurate insertion length model based on the experimental results. Using the proposed feeder mechanism and accurate insertion model, the buckling prevention and elimination performance were verified through the experiment on the robot system.