Development Of Actuators For Retinal Tear Surgery

Ophthalmic disease is a kind of serious harm and high incidence of diseases,due to the small size of the human eyeball,the internal structure is precise and very fragile characteristics,it is very difficult for doctors to perform surgery on it.Therefore,for diseases such as anterior retinal membrane and macular hole fissure,this subject developed a fundus retinal tear surgical actuator.It is installed at the end of the surgical manipulator arm,and it is cooperated with the manipulator arm to complete the peeling operation of the internal boundary membrane.Firstly,the operation procedure of internal boundary membrane stripping operation operated by doctors with hand-held medical instruments was analyzed to determine the size of the actuator into the eye,the degree of freedom of the actuator and the overall size of the actuator.Then the force of the actuator during the operation is analyzed to determine the required output torque of each motor and its precision performance.And then we have to think about how the actuator interferes with the rest of the surgical equipment and design the whole thing.Finally,ANSYS simulation analysis was carried out to continuously optimize the configuration and size of each part of the iterative actuator.The quality and size of the parts were reduced as far as possible without reducing the stiffness,and the integration degree of the actuator was continuously improved.Finally,the assembly of the whole actuator is completed.Secondly,due to the precision and importance of the eyeball,the control of the contact force between the actuator and the eyeball needs to be very strict in the operation process.As the force sensor is used in the biomedical field,fiber Bragg grating(FBG)is chosen as the force sensor.After completing the basic principle of FBG force measurement and the calculation and analysis of temperature compensation algorithm,the FBG embedded platform is designed.In a more efficient and reasonable way to complete the FBG embedding work.Thirdly,the construction of FBG calibration platform is completed.Although the FBG is a very linear sensor,the linearity decreases significantly with the introduction of external sleeve and glue interference.Therefore,this paper adopts the linear method,namely the least square method and the nonlinear method,namely the support vector machine method,to calibrate the FBG micro-force sensing system.The calibration results of the two methods are compared.At the same time,the feasibility of temperature compensation algorithm is verified on the calibration platform.Finally,the experimental platform of simulated operation for retinal retinal tear was built.In this experiment,the egg shell membrane of chicken embryo was used to simulate the need to peel the inner boundary membrane,and the manipulative manipulator and actuator were used to simulate the experiment.In the course of the experiment,the procedure and method of the operation are summarized step by step.Finally,the force of the actuator in the process of the experiment is analyzed,which proves the feasibility of the operation of retinal tweezers.