High-frequency-variation speed control of spindle motor for chatter vibration suppression in NC machine tools

This paper proposes a spindle motor control method for self-excited chatter vibration suppression in numerical control (NC) machine tools. In conventional NC machine tools, spindle speed is set to constant value during machining, and the spindle speed is determined according to analysis or operator´s experience. The proposed method reduces self-excited chatter vibration by varying spindle speed with high frequency during machining. This method can also suppress the disturbance derived from cutting resistance by repetitive control, and achieve spindle speed variation with high frequency by perfect tracking control. Finally, we show the advantages of the proposed method by simulations and experiments.