Torsion Vibration Analysis of Lead-screw Feed Drives with Changeable Table Position and Work-piece Mass

This paper presents an investigation of dynamic behaviors of free torsion vibrations of lead-screw feed drives using the finite element method (FEM) under consideration of changeable table position and work-piece mass, to which the effect of changing table position and work-piece mass on the first three modes of the free vibration is numerically analyzed. The results indicate that all the nature frequencies of the torsion vibration in the lead-screw feed drives are notably changed with the table position where the sensitivity increases with the vibration order, while they are linearly varied with the change of work-piece mass. With the increase of the pitch in the system, it is found that the sensitivity has some increase. After that, the dynamic responses of a machine tool rotor-screw system with the closed position loop of servo drive system that utilize notch filter to compensate the torsion vibration of first two orders are simulated numerically. The results obtained display that the compensation using the conventional notch filter cannot suppress those disturbances induced by the vibrations associated with the changing table position. These results suggest us that the changeable vibration characteristics due to the change of the table position should be taken into account in designing the compensation filter control systems for high precision machine tools.