Operation Comfort Analysis for the Master Manipulator of the Flexible Ureteroscopy Robot Based on Joint Torque

The master manipulator of flexible ureteroscopy (FURS) robot system plays an important role in the master-slave control and its operating comfort influences the efficiency and quality of the robot-assisted surgery. The evaluation mechanism of operating comfort is commonly implemented based on the human joint movements and ignores the joint torque, which significantly influences on the surgical procedure and outcomes. This paper proposes an evaluation model of upper limb operating comfort based on joint torque for FURS robot through the Lagrange equation and NASA joint torque model. The reliability of the proposed evaluation model has been verified by the rapid upper limb assessment (RULA) by software Delmia and the muscle fatigue experiments on ureteroscopy by both of robotic and traditional manual approaches. The results indicate that the comfort index based on joint torque can well reflect the operating comfort for the ureteroscopy surgeon. Using the same with the evaluation model, the muscle fatigue experiments also show that the improved efficiency and quality of the master manipulator for FURS, which can facilitate to improve the design and control of the FURS robot system.