The Oretical Study Of A Serial-pm With 3-DOF Parallel Manipulator

For improving the load carrying capability of parrllel manipulator and extending the degree of PM,a new kind of serial-PM is proposed in this paper: a 3-DOF parallel manipulators which connected with a spherical pair in series is being set as a mixed limb.To make the research more modular and systematic,the inner 3-DOF parrllel manipulator is a generalized 3-DOF parrllel manipulator.Based on different connected structure,two kinds of new serial-parallel manipulators are established: the basic coupled manipulator and the movement coupled manipulator.Based on the screw theory,the constraintsand parameter relationship of internal generalized 3-DOF parrllel manipulator are analyzed.According to the analysis result,the whole study about new serial-parallel manipulators includes several aspects,like generalized position analysis,generalized kinematics analysis,generalized dynamic analysis.Based on vector method,the generalized position model is built,and the inverse displacement analysis is obtained.Based on the vector's time derivative and the constraint relationship,the generalized kinematics model and the Jacobian matix and the Hessian matrix of the manipulator are carried out.Utilizing the principle of virtual work,the paper computes the relational expression of the dynamic load and the driving force,generalized dynamic model is built.In order to verify the accuracy of generalized analysis model,take new serial-parallel manipulators which include 3-SPR parrllel manipulator as an example and compute position analysis,kinematics analysis,dynamic analysis.Utilizing the CAD variation geometry method and Solidworks software,the workspace of main body is drew out.