Design Of The Novel Two Degree Of Freedom Translational Parallel Robot Performance Analysis And Optimization

The 2-DOF (degree of freedom) translation parallel robot, as an important component of low degree of freedoms parallel robots, has broad application prospects in electronics, packaging, medical and other fields because of simple structure, easy controlling and low cost in manufacturing. Take a new 2-DOF translation parallel robot as the research object, its kinematic characteristics, work space, spatial static stiffness and force transmissibility characteristics are highlight analysed. Based on that, the optimum design of the mechanism is finished.Kinematics equations of each branch chain of the compound chains (be a singular structure of the 3-UPU parallel mechanism) are established based on the DH method, and the kinematic characteristics of the singular structure are analysed by using geometric constraint conditions, then the results are checked through the numerical example and kinematics simulations. According to changing the joints' distribution, several topological structures of the compound chains are designed. Based on that, several novel 2-DOF translation parallel robots are structured.By an equivalent planar mechanism of the 2-DOF translation parallel robot, its kinematical equations are established, and the output velocity and acceleration equations are derived by taking the derivation and the singularities of the mechanism are analysed. The global dimension design space of the mechanism is built by means of the virtual mechanism method, the distributing rules of work space in the dimension design space are analyzed by using the mapping between the work space and the dimension design space.Based on the superposition principle at small strain and the virtual mechanism method, a quite comprehensive analytical approach of spatial static stiffness is proposed. By using this method, the six-dimensional spatial static stiffness model of the 2-DOF translation parallel robot is obtained, and its principal stiffness and divection are analysed. Using finite element soltware, the spatial static stiffness of the mechanism and the equivalent planar parallel mechanism are compared, which verify that the mechanism has more high lateral stiffness.Using the characteristic that the transmission angle has nothing the coordinate system, a non-dimensional index of the manipulability of the spatial parallel mechanism is defined. Combining the index and the dimension design space carries out the comprehensive optimization design for the 2-DOF parallel robot, which achieves good results.