Two DOF modeling with three-dimensional forces and robust chatter control in metal cutting by piezo-actuator

In turning, the occurrence of self-excited vibration, the so called chatter, is undesirable as it gives rise to production problems, causing detrimental effects on the machined surface finish and to decreasing the machining efficiency. In this paper, in order to suppress chatter, a piezoactuator is introduced for the regulation of the machine tool displacement and the metal cutting system is modeled as a two-degree-of-freedom uncertain system with three-dimensional forces. The novelty of the proposed model is the inclusion of hysteresis nonlinearities and time lag, which can explain cause of the chatter. To overcome the chatter during the cutting progress, a robust adaptive control law is proposed and the simulation results show that the proposed adaptive control law significantly eliminates the chatter phenomena.