| Serial-parallel machine tool is a new kind machining equipment, which is a combination between traditional machine tools and modern robot. It is a series parallel type NC machine tool structure which not only has high speed and high stiffness, but also has the characteristics of series machine that has long travel. Recently so many research results of Serial-parallel machine tool have been obtained, but there are so many problems to be solved. In the contents, dynamic characteristics of machine tool are most emergent and practical. There are so many driving joints and passive joints in the parallel structure. The dynamic characteristics of the parallel structure are affected by many factors, which make it more complex than that of traditional machine tool. Research on modeling and analysis of dynamitic characteristics of parallel mechanism is of importance for the development of the Serial-parallel machine tool.The paper studies the dynastic force and distortion of the 3-RPS parallel structure of the 6PM2 series hybrid type NC machine tool structure. Using the boundary element method and the combined theory of mechanic system to establish the dynamic mode of parallel mechanism, and regards the element as elastic body, thus the dynamic model of the 3-RPS parallel structure is built. Firstly the dynamic equation of element is established by BEM, and then several kind of compound methods are discussed, at last the elements of the 3-RPS parallel mechanism is analyzed in its different state, and program related are developed.Based on the above theory, some programs have been developed use FORTRAN language. By comparing the test solution with analysis solution by the boundary element method, it is proved that the dynamic model, the analytical method and the program are right. The BEM method has great potential in the analysis of structure characteristics of machine tool. Trough simulating the characteristics of the 3-RPS parallel mechanism, some conclusion can be obtained which is helpful to design the serial-parallel machine tool. |
PDF Full Text Request