Design Method And Motion Mapping Strategy Of Miniaturized Minimally Invasive Surgery Robot

The research on miniaturized Minimally Invasive Surgery(MIS)robot is of great significance to the development of robot assisted MIS.Closely coupled with China’s urgent demand for high-end medical devices,this dissertation studies key technologies and design theories of MIS robot miniaturization,making several achievements as concluded below.A basic design method of MIS robot is proposed based on study of the operating characteristics of MIS.Firstly,the effects of different basic configurations of MIS robot and instrument on motion performance of the robot are comprehensively analyzed,providing the configuration basis for mechanism design of MIS robot.Secondly,the existing cable-driven methods and configurations are summarized and analyzed,and the corresponding basic transmission models for these cable-driven configurations are established,providing the theoretical basis for the design and modeling of the cable-driven structure.A method to realize miniaturization design of MIS robot is summarized through investigation on the existing MIS robots.On this foundation,the feasible mechanism realization forms of miniaturized MIS robot,including a novel two Degree of Freedom(DoF)planar Remote Center of Motion(RCM)mechanism and an incision adaptive mechanism,are proposed.The structural characteristics analysis and kinematic performance evaluation of the mechanisms are presented,constructing the theoretical design basis for application of these mechanisms.According to the motion characteristics of the incision adaptive mechanism,an estimation algorithm for motion fulcrum is proposed,making the foundation for the establishment of master-slave motion mapping of MIS robot based on this mechanism.A novel cable-driven instrument with distal rotation function is designed to match the mechanism characteristics of the proposed miniaturized MIS robot,and the cable-driven structure and transmission model are correspondingly established.According to the structure characteristics of cable-driven open & close joint,the transmission model of variable curvature cable-conduit structure is established,and the transmission characteristic of the same structure is optimized.Moreover,a modeling method for grip force pre-compensation is proposed,which can be used to establish the compensation model of the grip force of cable-driven instrument and to realize the stable grip force output of MIS robot.Basic requirements and control strategies of master-slave motion mapping of MIS robot are studied,on which a new master-slave mapping algorithm based on separation of position and orientation and end isomorphism is proposed.This mapping algorithm can effectively reduce the kinematics calculation of master-slave motion mapping,simplify the complexity of control system,and thus help to realize the miniaturization design of the MIS robot.Several functional control strategies are designed to cope with situations and problems that may be encountered in the operation,such as instrument quick exchange,instrument beyond the scope of the endoscope,operating discomfort and interference between the slaves.As for the system development of miniaturized MIS robot,overall size of the robot is greatly simplified through creative design of the “three fingers” passive adjustment mechanism.Based on the detailed design of each structure unit,a prototype of the MIS robot “MicroHand S” is developed successfully.Tests and experiments are carried out to verify the performance of the slave,quick-exchange,transmission and grip force of the instrument and the master-slave mapping strategies.Finally,animal experiments are carried out to verify the comprehensive performance of the robot system.