Abstract: The machining of complex and precise parts continually brings new challenges to the performance of machine tools. To ensure the machining accuracy of parts, it’s necessary to predict the dynamic behavior of the whole machine tool in the design stage. Aimed at machine tool spindle systems, a coupling model between the spindle and machine tool is introduced and the existed problem of the joint dynamics identification in this model is also pointed out. In order to update this coupling model, a finite model updating technique based on frequency response function is proposed. The joint dynamics is modeled as a stiffness matrix which contains translational degree of freedom (DOF), rotational DOF and coupled DOF. Dynamic response data are measured to identify the joint dynamics between the spindle and machine tool and therefore the analytical model is updated. The experimental results show that the updated coupling model between the spindle and machine tool can reasonably reflect the effects of the machine tool structure on the spindle and predict dynamic properties of the spindle system after mounting, which can provide theoretical proofs for the digitalized design and manufacture of high performance machine tools.

Key words: Coupling, Joints, Machine tool spindle, Model updating, Parameter identification