| The eye is an important sensory organ of the human body,and the structure of the eye tissue is complex and fragile.This leads to problems such as complicated operation,poor visibility,and high precision requirements in ophthalmic surgery,especially fundus microsurgery,which imposes high requirements on the surgeon’s surgical skills.The use of ophthalmic surgical robots to assist doctors in ophthalmic surgery can greatly improve the accuracy and safety of the operation,and the realization of the remote motion center(RCM)system is the key to the realization of the functions of the ophthalmic robot.This paper analyzes the domestic and foreign research status of ophthalmic surgical robots and the characteristics and requirements of ophthalmic microsurgery.By analyzing the intubation mode,initial insertion point position and intraocular surgery range in ophthalmic surgery,based on the existing operating room layout and for the diversity of human anatomy,determine the spatial layout of the slave hand and the externally related dimensions,and summarize the design requirements and design parameters of the ophthalmic robot slave hand.The overall program analysis of the RCM organization was carried out.According to the design requirements,analyze the schematic diagram of the slave RCM mechanism,and use the Solidworks software to establish a three-dimensional solid model of the slave RCM mechanism of the slave manipulator that meets the design requirements.In order to analyze the motion accuracy of the RCM mechanism,firstly,the D-H parameter method was used to analyze the kinematics of the RCM mechanism,and the Monte Carlo method was used to simulate the working space of the mechanism.According to the forward kinematics formula,the inverse kinematics formula is deduced.On the basis of considering the error,the source of the kinematic error of the RCM mechanism is analyzed,the kinematic error model of the RCM mechanism is established and the Jacobian matrix of error identification is derived,and a method of error identification and compensation is proposed.In Matlab software,this error compensation method is used for simulation,and the accuracy of the RCM mechanism’s end point positioning before and after compensation is compared to verify whether the proposed method is correct.Finally,the finite element method is used to analyze the strength and stiffness of some important parts of the RCM mechanism,and the stiffness of the entire RCM mechanism is analyzed to verify the stability of the designed structure.The structure dynamics model of the RCM mechanism is established,and its various vibration modes are obtained by the modal analysis method,so as to prevent the structure from resonating and causing excessive deformation and laying a good foundation for the next analysis.The harmonic response analysis method is used to obtain the response characteristics of the RCM mechanism to external loads at different frequencies to verify its vibration isolation performance. |
