In this study, we have constructed a mathematical model that can analyze the coupled vibration of machine tool structure and feed drive systems. The model is proposed on the basis of the modal analysis of the actual machine tool structure. It consists of three translational and three rotational displacements of the bed, relative angular deformations between the bed and column, relative translational and angular deformations between the bed and saddle, and relative translational and angular deformations between the column and spindle head. In addition, each feed drive system is modeled using a vibration model, which has two degrees of freedom. The servo controllers of each axis are also modeled. To confirm the validity of the proposed model, frequency responses, motion trajectories of the feedback positions, linear scale positions, and the relative displacement between the table and head are measured and simulated. The effect of coupled vibrations on the tracking errors is examined with the help of both experiments and simulations. To investigate the effect of the servo systems on the vibration, both experiments and simulations are carried out by using feed drive systems in the following three conditions: mechanically clamped, servo-on, and servo-off. The results of experiments and the simulations show that the proposed model can express the mode of vibration and the influence of the condition of feed drive systems on the mode of vibration.
On the Effectiveness of Contouring Control for Machine Tool Feed Drive Systems
