Shinji Ishii

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 operators 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.

Experimental verification of chatter suppression in end milling process using cooperative control of spindle and stage motors

Chatter vibration is well known as an undesirable phenomenon, so various methods for chatter suppression have been proposed. Spindle speed variation as a triangular trajectory in the cutting process is one of the methods for chatter suppression. However, this method cannot suppress chatter vibration completely. Moreover, the triangular spindle speed variation requires large torque and a good response of the spindle motor. To solve these problems, this paper proposes a cooperative control of spindle and stage motors. The proposed methods are evaluated by simulations and experiments.