Research Of Surgical Instrument For Celiac Minimally Invasive Surgical Robot

Minimally invasive surgery(MIS) is characterized by slight trauma,little hemorrhage and fast rehabilitation when it comes to easing patients'pain. Compared with traditional operative method, MIS has clear advantage of reducing surgery and nursing cost, therefore it has been widely applied in surgical operation and is a fast developing area nowadays. Robot, compared with human hand, have unparalleled advantage in precision and range of motion, and it would greatly improve the efficacy and convenience of surgery if applied to laparoscopic operation, so minimally invasive surgical robot system has become a hot topic in robotics field.The work is supported by the National 863 high-tech project"Research on minimally invasive robot for laparoscopic surgery". In this text, modularizing design according to functional needs of surgical instruments,specific structure design of various modules,mechanics and kinematics analysis/simulation for surgical instrument are finished successfully.Firstly, according to the analysis of operation processes for robot assisted laparoscopic surgery, DOF settings and transmission structure are obtained. For surgical clamp, four degrees of freedom are operating rod's rotation,wrist's act of oscillating and two fingers'independent holding/pitching, respectively; for surgical Cautery, three degrees of freedom are operating rod's rotation,wrist's act of oscillating and finger's act of oscillating, respectively. The whole surgical instrument is divided into manipulator interface module,motor drive module and surgical instrument ontology module, then the overall architecture for the surgical instrument is obtained.Secondly, structural design of the modules above is introduced in detail. For manipulator interface module, clamp ring mechanism is designed to make the replacement of surgical instruments more convenient. For motor drive module, transmission route of motors and clutches are designed, and design of universality for clamp and cautery is introduced. For surgical instrument ontology module's design, general parts are staff rotation device and tension/guiding device, decoupling control algorithm for clamp's end-effector is introduced while non-coupling mechanism for knife's end-effector is designed.Finally, analysis and simulation of two kinds of surgical instrument are carried out. As for mechanical properties, force analysis and selection of clamp and cautery's driving ropes are introduced; rod stability and bending deformation of staff are analyzed; simulation(ANSYS) is used to analysis the maximum displacement and stress of the cautery's finger for the purpose of evaluating the strength of it. As for kinematical properties, all the transformation matrixes from the basement to the finger joints of clamp and cautery are deduced, and initial posture of the robot is calculated; with the use of ADAMS, coupling movement of the clamp and non-coupling movement of the cautery is simulated. The surgical clamp and the cautery were tested, coupling of the surgical was presented, and the non-coupling principle of the cautery was proved.