Research On Several Key Issues For Mechanism Design Of Force Feedback Master Manipulator

The master-slave surgical robotic system is a more effective surgical robotic system，theslave robot is the actual robot manipulator that performs the surgery within the patient’s bodywhile the master is an interface device that allows the surgeons to control the slave. Themaster-slave surgical robot system allows the human to provide high-level thinking and decisionmaking and allows the robot using its high precision and accuracy. The force feedback mastermanipulator is an important component of the master-slave surgical robotic system, the key issuessuch as workspace analysis, error modeling, gravity compensation have been studied, thefollowing aspects in the dissertation have been achieved：A computer program to calculate the kinematic model and the jacobian matrix of n dof robotmanipulator has been developed in MATLAB. The linear mapping relationship between the forcefeedback master manipulator workspace and the surgical robot workspace has been built.An algorithm for the workspace boundary of the n-R orthogonal manipulators has beendeveloped, sub workspace boundary surface of the last two joints is generated as initial subworkspace boundary，the cross sections of the initial sub workspace boundary are created withrespect to the preceding joint coordinate, the two end points, the point with maximum radius andthe point with minimum radius of each cross sections curve are defined as the feature points, theboundary curves and the boundary surfaces of the former sub workspace are determined by thesefeature points, then the workspace is computed by this iterative process, and the volume of theworkspace is calculated. A simulation has been performed on a3-R orthogonal manipulator.Simulation results show that the proposed algorithm has advantages of small amount of kinematiccalculations and high precision, and it can be used for the manipulators with parallel joints.In order to obtain a parametrically continuous model in the case of two adjacent paralleljoints or nearly parallel joints, an additional rotation term about the y-axis known as a Hayatiparameter is introduced as the fifth parameter. According to the differential theory, a new methodto calculate the differential vector of the end-effector is proposed to simplify the expressionsderived by Veitschegger and Wu. A linear error model that described the end-effector position andorientation errors of the master salve surgical robot system due to kinematics parameters errors has been presented. A computer program to perform the accuracy analysis is developed inMATLAB. This methodology and software has been applied to the accuracy analysis of amaster-slave surgical robot system which consists of PHANTOM force feedback device and DaVinci robotic arm. The position error in its workspace cross section (XOZ) has been plotted as3Dsurface graph and discussed. The orthogonal experimental design method is adopted for accuracydesign of the haptic manipulator. The kinematic parameter errors are considered as the factors andthe pose errors are considered as the response variable, simulation analysis for the accuracydesign has been performed.An energy approach to analysis the spring balancing mechanisms has been proposed, themono-articular spring balancing mechanism with auxiliary link for a2-DOF manipulator has beendesigned. The dynamic model of the PHANTOM force feedback device has been built, and thebackdrivability has been analyzed. The stiffness of a prototype force feedback master manipulatorhas been tested by experiment.