Stiffness influential factors-based dynamic modeling and its parameter identification method of fixed joints in machine tools

A universal dynamic model of fixed joints is built through considering the relative motion between the sub-structures of the fixed joints and the coupling among various degrees of freedom. The dynamic model may accurately reflect the dynamic characteristics of the joints. Based on the inverse relationship between the frequency response function matrix and the dynamic stiffness matrix of a Multi-Degree-Of-Freedom system, a high-accuracy parameter identification method is proposed to recognize the dynamic model parameters of the joints using the dynamic test data of the whole structure including the joints. The error between the theoretical and experimental results of the model is less than 10%, while the error of the Yoshimura model is three times bigger than that of the model. The effectiveness and accuracy of the dynamic model and its parameter identification have been validated. The establishment of the model will provide a theoretical foundation for the precisely dynamic modeling of the CNC Machine Tool.