Type Synthesis And Performance Analysis Of Parallel Mechanism

Since the application of 6-DOF parallel manipulator to the flight simulator in 1965, the parallel robots named Stewart platform have obtained much development in both theory and practice area. However, there is a lack of deficient DOF mechanisms due to the difficulties of the type design of parallel manipulator.as the kinematic performance is determined by the mechanism architectures themselves. So the innovation of the structure type of the parallel robots is more crucial in the robotic area. For this purpose, the author has given more detailed and thorough study to type synthesis of the deficient-DOF manipulator from the viewpoint of mechanism. The parallel mechanism is composed of kinematic pairs and chains. The traditional types of pairs are prismatic pair, revolute joint, spherical joint ,helix, cylinder, and universal joint etc. But it is difficult for these pairs to constitute 2-5 DOF branch. This paper present several novel compound pairs with modularization structure which can perform 1-D rotation and 1-D translation for the translation-and-rotation universal joint and perform 2-D plane translation for the pure-planar-translation universal joint, and the pure translation universal joint which can implement pure translation. Furthermore, the 2-5 DOF kinematics branches are designed. By analysis using screw theory, we can know that they all have the determined kinematics characteristics, which are very crucial for the mechanism design of the manipulators. Based on that, we have also proposed 2-5 DOF novel parallel mechanisms with feature by the constitution laws of mechanism, those mobile platforms can implement 2-D plane translation, 3-D pure translation, 2-D translation and l-D rotation, 3-D translation&l-D rotation, 3-D traslation&2-D rotation, respectively. Accordingly, it is of important significance for the design of the parallel machine and manufacturing areas etc. The paper has also analyzed the performances of the novel 2-5 DQF parallel robot mentioned above. For example, the forward and inverse kinematic solutions, the Jacobian matrix, isotropy and workspace at all.