Mechanism Performance Analysis And Trajectory Planning Of A 3-DOF Knee Grinding Robot

In recent years,with the development of computer technology,medical imaging technology and robot technology,robot assisted medical technology has been widely used in the field of knee replacement surgery in the Department of orthopedics.Because,there are many problems with the replacement of artificial kee joint such as high technical requirements for doctor,low grinding accuracy of artificial,inaccurate measurement and unstable grinding.But the robot-assisted knee arthroplasty has the merits of minimally invasive,high precision of grinding,reasonable preoperative planning,and quick recovery of postoperative patients.Based on the analysis of the characteristics of the artificial knee arthroplasty and the structure of the knee joint Robot assisted technique was introduced in the knee replacement operation.In order to improve the grinding precision of knee joint and combine the advantages of series robot and parallel Robot,a serial and hybrid 3-DOF robot for knee joint grinding replacement is designed,which can replace the doctor to finish the grinding of the focal position of the knee joint.First based on the background of knee arthroplasty,the design requirements of robot for knee joint grinding are put forward.Selecting the coordinate form material,connection and driving mode of robot a 3 degree of freedom knee grinding replacement robot is designed.The static stress and strain analysis of the robot is carried out by using ANSYS software,and the static analysis of the robot is obtained.Secondly,the kinematics of the robot is studied,and the Jacobi matrix and H matrix,the inverse kinematics equation and the positive kinematics are deduced.The inverse kinematics equation is verified by numerical simulation and virtual prototype simulation.The workspace,dexterity and stiffness of the robot are analyzed,and the static performance of the robot is discussed.Then using Lagrangian dynamics equations for the robot serial hybrid were dynamics modeling,,and the correctness of the kinetic equation is verified by using the simulation technology of ADAMS and the numerical calculation method of MATLAB.Finally,using the artificial knee replacement surgical procedure for reference,a plan for grinding the knee joint grinding robot was planned.The coordinate transformation relationship between the femur coordinate system and the fixed reference frame of the robot was determined by the three-point calibration method.Based on the patient prosthesis,a grinding trajectory planning method is established.The method firstly determines the surface equations and boundary equations of the prosthesis to determine the shape of the femur to be ground.Then the path trajectory equations were obtained by sequentially truncating the prosthesis using the surface distance perpendicular to the prosthesis interval of one knife,and the planning method was simulated and analyzed.Through the analysis of the robot's structure performance and the trajectory planning method of the knee joint grinding,to lay the theoretical foundation for the design control and clinical application of such surgical robot and provide technical support.To promote the development and application of robot assisted surgery technology in China.