The Mechanical Structure Design Of The Main Hand Of The Surgical Robot With Force Telepresence

The use of master-slave minimally invasive surgical robots for minimally invasive surgery has gained more widespread acceptance and application,not only freeing doctors from traditional minimally invasive surgery but also reducing patient trauma and reducing postoperative recovery time to reach the doctor Suffering a win-win goal.The master manipulator is an important part of master-slave minimally invasive surgical robots and is a carrier of human-computer interaction.The mechanical design of the master manipulator directly affects the performance of the whole minimally invasive surgical robot system.In this paper,funded by the Tianjin Natural Fund for new projects,the mechanical structure design,kinematics analysis,structural optimization analysis and simulation verification of the main manipulator are carried out.Firstly,the design requirements are proposed,and the mechanical structure design of the main manipulator is established according to the design requirements.The main manipulator is established from the heterogeneous 6+1 DOF tandem configuration.The master manipulator is composed of a base frame,big arm,small arm,posture mechanism and a clamping mechanism.The rotation of the base,the pitching of the small arm and an attitude degree of freedom deliver the output of the motor located away from the joint for traction through the wire transmission system.A feasible pre-tightening mechanism is designed,which has no backlash under reasonable preload,so that the output power of the motor is more accurate and stable.According to the design requirements,the counterweight of the big arm and small arm was analyzed,and the type selection of the motor was completed with the counterweight,and the main load-bearing parts were analyzed by the finite element method.Secondly,in this paper,a rigid-flexible transmission structure is adopted,that is,the rigid steel structure is replaced by the flexible steel wire in the non-travel section under the condition that the travel angle of the driving wheel is not big.The stiffness formula of the rigid flexible transmission structure is calculated.The transmission error formula and the natural frequency formula of the horizontal and vertical vibration of the transmission system are deduced theoretically.The parametric analysis of the relationship between transmission stiffness and transmission error,natural frequency of the horizontal and vertical vibration of transmission system is carried out.Through the ADAMS simulation and construction of the experimental platform for testing,using the comparison method,it is concluded that the transmission efficiency of the rigid flexible transmission structure is higher than that of the flexible steel wire transmission structure.Finally,the D-H method is used to establish the kinematics coordinate system of the master manipulator,and the forward kinematics model of the end effector is calculated and solved.According to the kinematic model,the Jacobian matrix is calculated,and the manipulability and dexterity of the master manipulator are calculated and analyzed based on the Jacobian matrix.Using Monte-Carlo method to simulate the main manipulator's motion space to prove that the main manipulator meets the surgical requirements.And the forward and inverse kinematics simulation of the master manipulator is carried out respectively,so that the solution correctness of the forward and inverse kinematics of the master manipulator and the rationality of the structural design are verified.