Design And Motion Mapping Strategy Of A Variable Configuration Minimally Invasive Surgical Manipulator

Based on the requirements of the high-end medical equipment and the challenges faced by minimally invasive surgical robotic systems,this paper focus on the surgical manipulator miniaturization and generalization of procedures,and studies design theories and key technologies of cable-driven behavior,variable configuration surgical manipulator design,kinematics of rigid-flexible hybrid manipulator,master-slave motion mapping and control strategy,system integration and experimentation.This thesis makes the following creative achievements:The kinematic and mechanical characteristics of cable-pulley-driven and cablesheath-driven were analysed,which laid the theoretical foundation for the design of a cable-driven surgical manipulator.The design and analysis methods for the cablepulley joint,cable-driven flexible joint and gripper of surgical manipulator were established,and the design criteria of cable-driven joints were proposed,which provided methods for the design of cable-driven surgical manipulator.Based on the analysis of the design requirements of the minimally invasive surgical manipulator,the design concept of variable configuration minimally invasive surgical manipulator was proposed to meet the requirements of manipulator miniaturization and generalization of procedures.The configuration,structure,and cable-driven system of the manipulator were designed in detail.The extend-retract arm with rigid-flexible joint nested structure and wrist with “hinge-hook” structure were proposed and analysed.The kinematic and mechanical properties of the cable-sheathdriven of the manipulator were analysed and optimized.The prototypes of the variable configuration surgical manipulator were developed.The general kinematics analysis method of the rigid-flexible joint hybrid manipulator was proposed for the variable configuration surgical manipulator.Based on the assumption of the constant curvature model,the kinematics model of flexible joint was derived,and the kinematics relationship between coordinate systems was analysed,which laid a theoretical foundation for the kinematics analysis of the manipulator.Based on rigid body kinematics and flexible joint kinematics,forward and differential kinematics models of the variable configuration surgical manipulator were established.Based on the gradient projection method of singular robustness inverse,the inverse kinematics model of the manipulator was established.Based on the basic problems and models of master-slave motion mapping,combined with the structural characteristics of master and slave manipulators,a masterslave motion mapping algorithm with the position and pose separation was proposed.The master and slave manipulators have the same wrist degree of freedom(DOF)layout and wrist-point pose,and the master-slave motion control of position and pose separation was realized with the manipulator wrist point as the benchmark,thus simplifying the control algorithm.To realize safe and effective control of the manipulator,the master-slave motion control strategies were established.Based on the design and master-slave mapping of the variable configuration manipulator,a prototype of the surgical robot system was developed.Based on the prototype of the system,the clamping force,motion performance,joint stiffness,master-slave motion tracking,and suture operation of the variable configuration surgical manipulator were tested.The clamping force stability,configuration variability,reliability of payload capability,master-slave motion mapping accuracy,and complex surgical operation feasibility of the manipulator were verified.