Flexible Tactile-Sensing Gripper Design and Excessive Force Protection Function for Endovascular Surgery Robots

Research on endovascular surgery robots (ESR) is continuously developing, because ESR can protect surgeons from radiation exposure. For designing an ESR manipulator, the main challenge is controlling the soft surgical tools and measuring the endovascular stress simultaneously. To solve these problems, a flexible tactile-sensing gripper (FTG) is designed in this study. Firstly, a catheter grasping model is constructed, and the factors affecting the force measurement are quantitatively analyzed. Secondly, the simulation experiments based on FTG models with three different sizes are implemented. When the catheter force is too large, shrinking the grasping distance of FTG can avoid the surgical risk. This method protects the surgeon’s behavior and controls the catheter force at the same time, which is named excessive force protection function (EFPF). Thirdly, the FTG prototype which meet the surgical requirements is made and integrated into the ESR manipulator. This manipulator can measure the catheter forces by detecting the coordinate of marks on FTG surface. The calibrated FTG gets the average and maximum errors of force sensing approximately 37 mN and 223 mN, respectively. Finally, in the experiment of carotid artery catheterization, EFPF can control the catheter force within 393 mN, which is far less than the control group’s 1351 mN.