High-quality manufactured components with a fast production rate represent an increasing demand of the modern machine tool industry. Internal machining operations due to the large length-to-diameter ratio are highly prone to intolerable chatter vibrations and have proven to be an extremely challenging process. This paper presents a new method for a proper design of Direct Velocity Feedback (DVF) controller in order to extend the boundaries of stable cutting for internal turning with minimum control eort. Control eort and active damping performance are two counteracting parameters that aect the results of active vibration control. After properly implementing the DVF active control algorithm on the internal turning setup, stable boundaries for dierent control gains of DVF controller are thoroughly studied. The comparison shows that although high DVF gains may considerably improve dynamic stiness of the tool, it leads to maximum control eort and actuator saturation and, consequently, process instability. The proposed gain selection method results in a signicant increase in stable machining over the desired range of cutting conditions. The suggested design approach of the DVF controller can considerably improve the limitations of rough machining on long overhang boring bars

Keywords