Dynamic Characteristics Analysis Of 5-UPS/PRPU Parallel Machine Tool

With the development of science and technology, modern machine tools are developing towards high stiffness, high velocity, high precision and low weight. So the error brought by elastic distortion of components can't be ignored any more. Rigid body dynamics can't satisfy the requirements of industry. So dynamic characteristics analysis based on elastic body has become an important branch in machine tool research. The indexes of dynamic characteristics can also be the basis of structure optimizing. Thus, dynamic characteristics analysis has an important place in the research of machine tool.Taking 5-UPS/PRPU parallel machine tool(PMT) as the research object, D-H method and lagrange function are employed to get the adverse kinematics and rigid body dynamics model on the basis of others' work.The structure of PMT is simplified and equivalent geometry model is established by ANSYS. Three dimensional solid elements are chosen to partition the finite element model(FEM)of PMT. Relative movements between parts are described by defined pairs.Then, modal analysis of the machine is conducted and its nature frequency and vibration modes are obtained. Analyses the results got from modal analysis and gets the weak taches. Some conclusions are gained about the dynamic characteristics of the machine.Dynamic experiments of the machine are conducted, and the low nature frequencies are gained. The data obtained from experiments are compared to theoretical calculation results. Factors affecting the test and theoretical calculation are discussed. The results gained from experiment testify the validity of the FEM.