The Research On Intracranial Dexterous Localization Technology Of Concentric Tube Surgical Robot

In China,stroke has caused the most years of life lost in all kinds of cause of death,and if it is not treated in time,even if cured,it will cause irretrievable damage to patients.Compared with ischemic stroke,several intracranial hematoma removal programs for bleeds still have their own problems,including the accuracy of the operation influenced by the limitations of the operation field,the obstacle avoidance of the path influenced by the rigid tool,the limited accessibility caused by the limited size of the tools,and excessive bleeding caused by imprecision of operation.This project has developed a concentric tube surgical robot under the funding of the “Double-hundred Project” for scientific and technological innovation of Shenyang,“Remote Stereotactic Surgical Robot System Based on Image Cloud”.It is based on the design of mechanism,with mechanical and kinematic modeling as the key,and using shape sensing technology as feedback that effectively solves the problem of its dexterous positioning.According to the requirements of the degrees of freedom of the mechanism,the working space and the precision of the end-effector of intracranial hematoma removal surgery,it is proposed that the requirements for mechanism design of the concentric tube surgical robot;based on the design requirements and the idea of compact arrangement of the mechanism,each driving mechanism is compared to determine the final design of the mechanism;combining the singular analysis of six-degree-of-freedom robot,and then classified the singularities,it is determined that the robot smooth motion path selection method,and the smooth and stable motion process of the robot could be achieved.Trough the puncture experiment,the reliability of the mechanism and the stability of the motion are verified,and the foundation is laid for the realization of dexterous positioning.By analyzing the material characteristics required for the concentric tube,pseudo-elastic nitinol is selected as the material for concentric tubes.Cosserat rod theoretical model and the torsional compliant model are combined to propose the improved fast torsional compliant model as the mechanical model of the concentric tube.Based on it,according to the twolevel mapping,which includes the tube variable to the curvature and arc length,and then to basic cross-section coordinate systematic frame,realized by the kinematic modeling theory.Combining with the calculation method of the spinor algorithm and the exponential matrix,it is realized that the modeling of the forward and inverse kinematics of all the tubes.With help of the experiment,the accuracy of the modeling method is verified,and the dexterity of the positioning is increased.Based on the principle of FBG shape sensor,it is proposed that the characters of FBG sensor,the sensing theory of FBG technology,and the shape reconstruction scheme.Based on the principle of FBG sensing,it is proposed that the design requirements and design schemes of FBG shape sensor.It is designed that an appropriate and effective shape sensor assembly platform and scheme using the designing theory of the sensor's structure.The experiment is performed for verifying the feasibility of the designed assembly scheme.According to the simulation experiment of shape reconstructing,it is verified that the accuracy of the theory of shape reconstructing and the possibility of the realization of dexterous positioning.In summary,this subject is designed for intracranial hematoma removal surgery,and a concentric tube surgical robot system is designed,and the feasibility of the proposed method is verified by simulation and experiments.The context proposed in this paper,which includes mechanism design method,the mechanics and kinematics model method and the shape sensing research,provides a guarantee for the refinement and accurate positioning of concentric tube surgical robot.It has important reference significance for the application and research of the continuum robot conducting an internal surgery in a similar restricted cavity,and lays the foundation for the development of robotic surgical operations.