Structure Design Of Passive 7-DOF Minimally Invasive Celiac Sugery Robot And Study On Preoperative Positioning

With the development of modern robotics and medical technology, surgical robot is increasingly used in the field of minimally invasive surgery. Compared to conventional minimally invasive surgery, robot-assisted mode has greatly improved the accuracy and safety of surgery, meantime reduced surgical pain and recovery time of patients.Through in-depth study of minimally invasive surgical requirements, this paper presents a new kind of minimally invasive surgery mode in which the doctor directly controls the robot ends to achieve the surgical operation. Finish the structure design of passive 7-DOF minimally invasive celiac surgery robot and 3-DOF micro-operation instrument in consideration of the specific mode. Mounting platform of the manipulator is versatile, and can quickly switch between different surgical instruments such as laparoscope or surgical clamp.In order to enhance the operability of robot and save manpower, one-arm intraperitoneal image acquisition program and three-arm combination-type surgery program are studied with the use of the robot related.Based on the structural features of 7-DOF manipulator and related micro-operation instruments,this paper establish the kinematic coordinates of robot and get the kinematics,inverse kinematics models. Building the kinematics model and mechanism model by Matlab,then achieved the simulation. By comparing the errors between inputs and outputs, we draw the conclusion that the kinematics and inverse kinematics models are both correct. Input the link parameters into the kinematics model and finished the workspace simulation of mechanism fixed point and instrument operating point.Finished the finite element analysis of key components and the overall structure with Ansys, based on the analysis results, optimize the design of components; Inspecting the overall static stiffness and getting the terminal position error compared with the theoretical position, then certificated the positioning accuracy of the fixed point; finished the modal simulation of the overall structure, combining the form and frequency of vibration source,analyzed the possibility of resonance; By controlling the vibration source frequency, the resonance possibility is avoided, finally ensure the mechanism running accuracy.According to the robot assisted minimally invasive surgical operation requirements, we studied a preoperative arms positioning mode under multi arm coordinated working condition.With the consideration of avoiding moving interference and ensuring enough working space of instrument,established 3 evaluating principles of preoperative swing-bit effectiveness,writing M-files and carry out the associated simulation in Matlab, finally achieved the best arm swing-bit mode form based on the 3 evaluating principles. To further verify the practicability of the best mode, collaborative simulation analysis between the instrument’swork space inside body and doctor’s operation space outside body,finally proved the best arm swing-bit mode is with excellent operability.