Active Control of Machine-tool Vibration in a Lathe

In the turning operation the relative dynamic motion between cutting tool and workpiece, or vibration is a frequent problem, which affects the result of the machining, in particular the surface finish. The tool life is also influenced by the vibrations. When the working environment is considered, noise is frequently introduced by dynamic motion between the cutting tool and the workpiece. By proper machine design, e.g. improved stiffness of the machine structure, the problem of relative dynamic motion between cutting tool and workpiece may be partially solved. However, by active control of machine-tool vibration, a further reduction of the dynamic motion between cutting tool and workpiece can be achieved. It was found that adaptive feedback control based on the filtered-x LMSalgorithm enables a reduction of the vibration with up to 40 dB at 1.5 kHz and simultaneously with approximateely 40 dB at 3 kHz. A significant improvement of the workpiece surface was observed and a substantial improvement of the acoustic noise level was obtained with adaptive control.