Research On The Control Method Of Robot In Ophthalmic Microsurgical

In this paper,the key techniques of ophthalmic microsurgery assisted robot system are researched in view of the characteristics of high operation complexity,high accuracy,dynamic and uncertain operation of posterior segment surgery.The typical operation processes such as minimally invasive orifice alignment,insert movement and intraocular movement solve the core theoretical and technical problems of master-slave control and cooperative control,and verify the effectiveness of the control method through simulation and experiment.Realized the precise operation of the ophthalmology microsurgery assisted robot.First,this study carried out the design of the control system.According to the system composition of the ophthalmology microsurgery assisted robot,the structure of the master and slave hands,The distributed computing and I/O connection are used to design the layered hardware and software structure,using the compilation environment of VS2017+Qt+Open Inventor,the human-computer interaction interface and 3d virtual interaction interface in the human-computer interaction layer are designed.Second,in the study of master-slave control,on the basis of RCM mechanism kinematics,a grouping control strategy of posture separation was proposed,and a master-slave heterogeneous position incremental master-slave control method was studied.In the slave hand motion planning,using the cubic polynomial to ensure the continuity of the slave hand joint displacement and velocity,the master hand jitter filtering algorithm is designed based on the bandlimited multiple fourier linear combiner,which cooperates with the master-slave proportional mapping and linear motion intent Recognition method to achieve precise control of the follower.Finally,the security mechanism of master-slave control is studied.Third,in the research of collaborative control,based on the basic principles of admittance control,a variable parameter admittance control algorithm based on speed and force information is designed to make the slave hand show flexibility in a large range of movement and quickly respond to manpower changes.In a small range of positioning close to the human eye,it exhibits relatively rigid characteristics,reducing the physical tremor of the human hand.Aiming at the effect of gravity on the display of the six-dimensional force sensor when the attitude of the actuator module changes,a gravity compensation algorithm is designed to compensate the gravity component in real time.Based on the gravity compensation algorithm,a compliant control method for catheter insertion operation was studied,and the axis of the actuator and the axis of the sleeve were automatically coincided during the insertion phase.Finally,simulation and experiment are used to verify the effectiveness of the control method.In the simulation,Adams and Matlab platforms were used to simulate the positioning function,the six-dimensional force data in Adams was used to verify the initialization algorithm in gravity compensation,and Coppelia Sim was used to verify the effectiveness of the flexible control method for catheter insertion.In the experiment,the master jitter filtering experiment verified the effectiveness of the jitter filtering algorithm;in the master-slave control trajectory tracking experiment,the tracking index of the large-scale moving mechanism is about 0.18,and the tracking index of the RCM mechanism is about 0.24.The performance is good;in the gravity compensation experiment,the average value of the absolute value of the force compensation under no load is about 0.11 N,and the average value of the absolute value of the torque compensation is about 0.01 N ·mm,which verifies the correctness of the gravity compensation algorithm.In addition,the feasibility of ophthalmic microsurgery-assisted robot for posterior segment surgery was verified on the eyeball model.