Design And Kinematics Simulation Of Hand-held Microsurgical Robot

With the continuous development of robot technology,robot-assisted surgery has been more and more applied in surgical operations,and has achieved commercial success.However,in microsurgical operations,due to the limited operating space and obstructed vision under the microscope,the realization of micron-level accuracy of the existing teleoperated and cooperative surgical robots in microsurgical operations still faces great challenges.As a new alternative to traditional surgical instruments,the hand-held surgical robot can be manipulated flexibly by the surgeon,while retaining the sense of interaction between the doctor and the patient,and has tremor-filtering and motion zooming functions.In this paper,the kinematics and structural design of the hand-held microsurgical robot are studied on the application platform of retinal surgery.First of all,taking the action of retinal peeling surgery as an example,the performance requirements of the robot are analyzed and the design indexes of this paper are determined.On this basis,the overall design of the expected surgical system is introduced,and a handheld microsurgical robot is designed using the Gough-Stewart configuration,and the theoretical model of the handheld robot is established.The inverse kinematics of the hand-held robot is analyzed based on the remote center of motion by using vector analysis method to meet the need of minimally invasive incision in surgery.A simplified model is established based on the virtual prototype technology of ADAMS to verify the correctness of the inverse kinematics model.Meanwhile,the forward kinematics is analyzed by using Newton-Raphson numerical iteration method and its correctness is verified.Secondly,the factors affecting the workspace of parallel robot are analyzed,and the polar coordinate search method is adopted as the searching method of the workspace of the hand-held robot.Under the condition that the flexure hinge does not yield,the motion range of the robot is analyzed,and on the basis of selecting the nickel-titanium alloy wire as the flexure hinge,the influence of different wire diameter of the nickel-titanium alloy wire on the workspace of the handheld robot is analyzed.According to the design index of motion range,the workspace of the designed handheld robot is drawn after the wire diameter of the nickel-titanium alloy wire is determined to be 0.2mm.Then,on the theoretical basis of the above analysis,the structure of the hand-held robot is specifically designed,including the design of the structural parts,the selection of the piezoelectric motor,the structural design of the driving unit,etc..The finite element analysis of the whole structure of the hand-held robot is carried out by using ANSYS software,and the stress of the flexure hinge is analyzed in several extreme working conditions.The simulation results show that the force of the flexure hinge will not exceed the yield limit when the external load is borne,and the whole hand-held robot will not deform unrecoverably.Finally,in order to verify the rationality of the design,the principle prototype of the hand-held robot is developed,and an experimental test platform is built.The resolution and repeated positioning accuracy of the hand-held robot are tested in the grounded version.The test results show that the virtual prototype of the designed hand-held robot can achieve micron motion and meet the design criteria.