Modal analysis of machine tools during working process by matrix perturbation method

All the dynamic characteristics of machine tools, especially modal behaviors, should be known during the whole working process, in order to obtain high surface quality and accuracy of machined parts. In this paper, matrix perturbation method (MPM) is adopted to perform the modal analysis on machine tools under working state. A VMC0540d high-speed milling machine tool´s modal variation within its working space is calculated by MPM and dynamically mapped. A classical modal solution method, Block-Lanczos method is used as a comparison and modal measurement experiment is carried out as verification. The results show that the machine tool´s natural frequencies have a significant change with the maximum variation up to 40% during machining process. Compared with Block-Lanczos method, the time for model re-construction of first-order matrix perturbation method is obviously reduced. Modal experiments show that the MPM is credible and the error is within 10%.