Indirect measure of joint torques of surgical instrument in robot-assisted laparoscopic surgery

To solve problems due to absence of force feedback and provide a better medical environment for surgeons, using haptic feedback is proposed. A precondition to apply the haptic feedback is to measure the force however it is inconvenient to attach sensors to the end-tip of surgical instrument. Sensors can't endure high temperature and high pressure while surgical instrument is being sterilized. As a result, this study aims to measure force indirectly at the driving part and operate the traction suture thread experiment. When force is measured using indirect method, uncertainty factors, such as back-lash of the motor or various frictions disturb the actual data. One of the important difficulties is the wires being twisted while surgical instrument is rotating. As a result, we design a structure to prevent twisting and to confirm the repeatability of the measured force by the indirect method.