Design And Gripping Force Of Minimally Invasive Robotic Surgical Instruments

With the increasing application of robot technology in medical treatment,the burdens of surgeons and patients are reduced.Surgical instruments are one of the key components of minimally invasive robotic system,and the research on griping force of the surgical instrument end effector is also one of the main parts of minimally invasive machine mechanical property research.Surgical surgeons need to control the surgical instrument end effectors to complete hand movements.For most surgical instruments,the end effector is driven by steel cable,which can transfer power to the far end effector in a narrow space.The following work has been done in this paper:Firstly,a surgical instrument is designed for minimally invasive surgical robot.The power part,transmission part and the end effector of the surgical instrument were designed and analyzed.The weight of the surgical instrument can be reduced by using steel cable transmission,which meet the actual operation needs such as the degrees of freedom and other work requirements,and reduce the mass of the surgical instrument.Secondly,the forward and inverse kinematic analyses of the surgical instrument are carried out,and the mapping relationship between the rotation angle of each joint and the position and posture of the surgical instrument end effector is obtained.The dynamic analysis is performed,and the relationship between the motion state and torque of the end effector could be obtained.Then MATLAB Robotic toolbox was used to simulate the workspace of surgical instruments,and the workspace cloud map of the surgical instrument end effector is obtained.Thirdly,aiming at the safety problem of grip force of the different surgical instruments with the same opening & closing angle in minimally invasive surgical robot,which is controlled by using the same master manipulator,the grip force of surgical instrument end-effector is studied,and a mathematic model of the end-effector’s grip force is established without force sensor.which provides theoretical basis for effective and safe ripping force control in future.Finally,the grip force model is simulated and researched by MATLAB.the curves of the grip force with/without friction and creep deformation,and the grip force and the pulling force of the suture needle are given especially.The simulation results show that the mathematical model of the grip force is closer to the actual situation,which provides theoretical basis for effective and safe ripping force control in future.