Error Analysis Of 1-PU/2-UPS Parallel Kinematics Machine

Recently years, the application of Parallel Kinematics Machine is more and more extensive, but its development is still restricting to a certain extent because of its precision. With the development of the technical requirements, error analysis of PKM could not only be confined to some certain aspects of transmission system, but also make more researches on the multiple error factors of PKM systems to make a comprehensive analysis. This paper takes the PKM whose transmission mechanism is 1-PU/2-UPS as the research object, the main error factors are analyzed comprehensively by means of mathematical analysis and software simulation, and the more reliable theoretical basis is obtained for the error compensation and distribution. The main research contents of this paper are as follow:First, the structure of 1-PU/2-UPS Parallel Kinematics Machine theory is analyzed with the methods of screw theory and the ordered SOCs, its structural characteristics and basic motion properties could be cleared.Second, the kinematics and dynamics of 1-PU/2-UPS Parallel Kinematics Machine are studied, including kinematics, the singularity, the moving trajectory of platform, velocity and force analysis of the platform and the chains, and so forth. And Matlab and Adams are used to co-simulate the 3D virtual model.Third, multiple possible error factors of each system of 1-PU/2-UPS Parallel Kinematics Machine are analyzed, and the main error factors are analyzed by modeling and simulation, such as the length errors of driving chains, the position offset errors of kinematics pairs, the clearance errors of kinematics pairs, the elastic deformation errors of flexible chains in rigid-flexible coupling system and the executive errors of the end actuator etc. The method of regarding the length error of the driving chains as the "intermediary" is proposed, the error change of the end of the machine under the comprehensive influence is got. This paper achieved the purpose of comprehensive analysis of the error at last, which provides a reliable basis for error compensation.