Design of a novel surgical instrument for minimally invasive robotic surgery

Minimally invasive robotic surgery (MIRS), compared to open surgery and traditional minimally invasive surgery, has advantages especially for patients and surgeons. In MIRS the surgeon´s capabilities are extended for kinds of dexterous instruments, and surgeons could perform precise and dexterous movements which are difficult to carry out by means of rigid instruments. In this paper, the design of a novel 4DOF dexterous surgical instrument for MIRS is presented. After analyzing feature of surgical instrument for MIRS, a novel 4DOF dexterous surgical instrument based on pulley-tendon mechanism is developed. The end effector of such an instrument is articulated, providing 4DOF without coupled motions. Force limited function is realized by conical axis mechanism, and a new quick change interface is designed based on trapezoidal clutch plate and magnetic sensors to change instruments according to the operation requirement. Strength checking of key parts are also analyzed. The experimental results demonstrate that the proposed surgical instrument can perform 4DOF uncouple motions with 10 mm outer diameter, except that the fast interface meet the fast and reliable requirements. The surgical instrument proposed in this paper has a good motion performance, flexibility and maneuverability. The surgical instrument satisfies the requirements of MIRS, laying a solid technical foundation for clinical application.