Study On The Structural Synthesis About The Partly-DOF Parallel Robot Mechanisms And Constraint Chains

Parallel Robot Mechanisms, in which one or more parallel organs are included, is a new type of manufacturing mechanisms thriving in recent years of the world. Comparing with the series-wound configuration, the parallel configuration has special advantage like better rigidity, better precision, higher speed and acceleration which in all manufacturing fields it enjoy wider application prospect. Partly degrees of freedom parallel robot mechanisms has become a significant tendency in the field of parallel configuration equipment's development.Comparing with 6-degrees of freedom, the partly degrees of freedom parallel robot mechanisms is more complicated in the kinematical features and this has results in serious lack of the latter. So to research on the partly degrees of freedom parallel configuration is of more significance and values both in theory and in the application. Besides, the performance of the parallel robot mechanisms is directly influenced by the factors like constraint chains' configuration types and joints and the freedom degree configuration, precision and rigidity. Under such circumstances, the research on all types of sub-chains and their kinematical features is imperative.Focusing on partly-degrees freedom parallel mechanisms' configuration design and the constraint chains, and based on a wealthy research on the development tendency on the parallel mechanisms, this thesis mainly makes rather deep research on parallel configuration synthesis, constraint chains structures and classifications, variant constraint chains configuration's kinematics, static stiffness , elasticity dynamics, precision and errors. The contents includes:(1) This thesis mainly researches the screw theory, the Topology configuration theory and the Algebra of Lie group which are all tightly associated with the parallel mechanisms. It sets forth relevant basic concept, calculation and principle which lay academic groundwork for further research.(2) It researches current 3 main methods of parallel mechanism configuration which includes constraint synthesis on the screw theory, the structural synthesis on the screw theory and the displacement flowing synthesis and makes a full and clear comparison on their strong and weak points. Based on current theory, it puts forward the constraint accession synthesis method which expands parallel configurations.