Kinematics Analysis And Simulation Of 3-DOF Parallel Mechanism

With the development of parallel mechanism theory, technology and application, spatial imperfect-DOF parallel mechanism have received much attention for the advantages of their simple structure and low cost. At present, the research of imperfect-DOF parallel mechanism mainly focus on the representative types of planar 2-DOF 5R mechanism, planar 3-DOF 3-3R mechanism, spherical 3-DOF 3-3R mechanism, Tricept parallel mechanism and spatial three-translational parallel mechanism.According to the theories of the structure synthesis of parallel robot mechanisms, three representative types of 3-DOF parallel mechanism platform are synthesized and investigated, then the characters of self-structure and motion form are analyzed in brief. The direct and inverse kinematics constraint equations are used with the structural character of mechanism platform, from which the direct and inverse kinematics expressions can be derived. The velocity and acceleration expressions are deduced from first-order and second-order time derivative of the inverse kinematics equation. In conclusion, the relevant direct kinematics is obtained by the solution instance of position analysis.Workspace of parallel mechanism is scaled as one of most important indications. The factors for affecting workspace of parallel mechanism are analyzed in detail, and solid skeleton maps of three mechanism platforms are represented by the numerical method which is based on the inverse kinematics and limited workspace’s boundary.The software of Pro/E is used in the modeling and simulation of these three representative 3-DOF parallel mechanism platforms. By setting reference point on mobile platform, the position transformation graph is given, which verify the correctness of the theoretical position analysis.Finally,after machining and assembling,the rationality of these parallel mechanism platforms is validated.The research of this thesis establishes theoretical basis for the future research and development of these 3-DOF parallel mechanisms practicality.The kinematics analysis and simulation with software Pro/E not only validate the rationality of these parallel mechanism platforms, but also verify the correctness of theoretical position analysis further,and promote the development of theory and technology for the parallel mechanism.