Kinematic Modeling And Simulation For The 3-prs Parallel Mechanism Based On Screw Theory

3-DOF parallel manipulator is an important branch of in the field of parallel manipulators. With the wide application of 3-DOF parallel manipulator in industry, recently more and more researches focus on this field. 3-PRS parallel manipulator is a typical kind of 3-DOF parallel manipulator and has a highly practical value. In order to provide a theoretical basis for its design and producing, this dissertation has investigated kinematic mathematical modeling and simulation analysis of 3-PRS parallel manipulator.Firstly, an overview to the rcent research about 6-DOF and 3-DOF parallel manipulators is presented, and the research achievements and methods previously used are introduced additionally.Secondly, the kinematic analysis of a 3-PRS parallel manipulator is conducted, in which closed-form solution for inverse kinematic problem, numerical solution for direct kinematic problem, and implementation of configuration visualization are addressed. Both screw theory and derivational approach are applied for the establishment of the first order and second order kinematic influence coefficient matrix.Comparing with each other, screw theory combined with kinematic influence coefficient is more adaptively applied to establish the equations.Thirdly, adopting an adaptive way to describe the working space of this kind of manipulator and based on the solution of inverse kinematics and comprehensively considering structural constrains on its working space, study on its working space and design of working space simulation system have been performed with MATLAB software. According to the results of simulation, the analysis of the structural parameters impacting on working space has been done. Further, based on the first order kinematic influence coefficient matrix, several typical singular configurations are put forward with deeply anlaysizing singular equation.Finally, a 3-PRS parallel virtual prototype model and kinematic simulation are shown with the ADAMS software and accuracy of kinematics obtained in this work has been verified. Greater range of posture space of the parallel manipulator is acquired by the kinematic simulation of structural parameters' design of experiment.