Theoretical Study On 4PSS+SP Parallel Surgery Operating Hand Mechanism

With the development of science and technology,it is found that the parallel mechanism has the advantages of high precision,compact structure,large bearing capacity,no accumulated error,high stiffness,etc.compared with the serial mechanism.Therefore,the parallel mechanism is often used in many fields,such as driving motion simulator with high precision,microsurgical robot,attitude adjustment of motion system and so on.And for the parallel mechanism of limit degrees of freedom,its motion branch provides the constrained force and constrained torques,and its structure is simple and easy to control,which is more widely used in medical equipment and industrial production and so on.The application of the limited-DOF parallel manipulator to the multi-manipulator mechanism can realize multiple operations in the same position,which can provide greater driving force and simple control of the multi-manipulator.Therefore,according to the characteristics of the limited-DOF parallel mechanism itself,it is also a new exploration to the posture adjustment and driving of the manipulator.In this paper,a 4-DOF 4PSS+SP parallel mechanism with intermediate passive constraint branch is studied and applied to the parallel multi-manipulator.The degree of freedom of the mechanism is analyzed and calculated,and the three-dimensional solid model of the mechanism is established by using advanced CAD.According to the vector method,the position inverse solution of the mechanism is obtained,and the correctness of the position inverse solution is verified.Then the wireframe of the mechanism is established by using the advanced CAD software,and the workspace of the mechanism is obtained by using the secondary development of the advanced CAD software and the VB program according to the CAD variable geometry method.By using the velocity projection theorem and the binding force / torque of the constraint property of with the limited-DOF parallel mechanism,the 6×6 Jacobian matrix with the intermediate constrained branch 4PSS+SP parallel mechanism is obtained.Based on the kinematic analysis of the mechanism,the Hessian matrix is obtained,and the relationship between the motion and the driving of the end of the parallel mechanism is obtained and its correctness is verified.The static and dynamic models of the 4PSS+SP parallel mechanism are obtained by using the principle of virtual work.The dynamics simulation is combined with the dynamic model of the mechanism by computer MATLAB software.The correctness of the dynamic model is verified by programming simulation.Through the theoretical study of the 4PSS+SP parallel mechanism,it is applied to the surgery multi-manipulator based on the knowledge of the manipulator,and analyzes the parallel multi-manipulator mechanism finger position analysis,kinematics analysis and statics analysis.The analysis and verification provide an effective basis for the application of the institution to other fields.