Research On Preoperative Positioning Mechanism Design And Preoperative Planning Of Minimally Invasive Surgical Robot

The overall structure of the minimally invasive surgical robot is complex,with multiple redundant degrees of freedom robotic arms,and the end effector of the robot works in a narrow abdominal cavity.The existence of the above-mentioned problems makes the preoperative planning of the robot difficult and affects the safety and feasibility of minimally invasive surgery.Therefore,this article combines the actual situation of minimally invasive surgery to design a new type of preoperative positioning mechanism,and at the same time,for the difficult problem of preoperative planning,a preoperative planning method based on multi-objective particle swarm optimization algorithm was proposed.Firstly,based on the flexibility of the robot,the working space and the requirements of minimally invasive surgery,a new type of preoperative positioning mechanism was designed.At the same time,to prevent collisions between multiple slave manipulators of the robot,redundant degrees of freedom were designed to increase the working space of the slave manipulator.The gravity of the slave manipulator was compensated by using the constant force springs,which can improve the flexibility of the joint.Threedimensional modeling of the overall structure of the preoperative positioning mechanism was carried out through Solid Works software.Secondly,the preoperative positioning mechanism was a passive part.All joints of the passive part remain immobile during the operation,so the forward and inverse kinematics of the active part were only analyzed by using the D-H method.At the same time,the Jacobian matrix of the active part and the working space at the end of the robot were deduced and analyzed to verify the working performance of the robot.Then,according to the physical characteristics of different patients and related knowledge of anatomy,a mathematical model of the location of the lesion and the incision area of the left and right surgical instruments was established to provide a basis for the preoperative planning algorithm.To avoid collisions between the endoscope arm and the surgical instrument arm,and between the endoscope and the surgical instrument during the operation,a collision constraint model was established.Starting from the operating performance of the surgical robot,the objective functions were proposed to facilitate the comprehensive performance evaluation of the non-inferior solution combination set obtained by the optimization algorithm.Finally,the validity of the preoperative planning method based on the multi-objective particle swarm optimization algorithm was verified.The preoperative planning plan obtained by this method was compared with the preoperative planning plan formulated by a doctor with rich clinical experience from the three perspectives of visibility,operability,and hand-eye coordination.The result showed that the preoperative planning method proposed in this paper has better performance.