Two degree-of-freedom modeling and robust control of chatter in metal cutting by using piezoactuators

Self-excited vibrations, also called chatter, are known to cause detrimental effects on the machined surface finish while decreasing the machining efficiency and productivity. Chatter is small-amplitude and high-frequency vibration, and an active vibration control providing a force to the cutting system is necessary to overcome the chatter effect. To provide such a force, piezoelectric actuators have been introduced into the metal cutting systems. In this thesis, the metal cutting processes are described as two degree-of-freedom systems with two-dimensional or three-dimensional forces. One of the main contributions in this thesis work is that the hysteretic characteristic models are incorporated into the chatter suppression control in metal cutting systems. It should be noted that this incorporation severely complicates the tasks of control law designs and analyses. In order to overcome the chatter effect, several robust adaptive control schemes are proposed for different scenarios in this thesis. The simulation results show significant reduction of chatter by using the proposed adaptive control laws in all the case