Model Predictive Control Based Chatter Suppression in Milling Process via Piezoelectric Stack Actuators

Abstract

Chatter is a kind of self-excited vibration occurred in the machining process which limits the productivity, causes inferior work piece quality and even shortens the life of cutting tools and spindles. The control of chatter has become one of the major concerns in industry. In this work, a model predictive control based method is developed to suppress chatter in milling process. Firstly, by integrating the spindle, the piezoelectric stack actuators and milling process, a discrete model is established. Then, Padé approximation is used to approximate the time delay and the nonlinear time-varying system is transformed into a linear time-invariant system. Finally, receding horizon optimization and feedback compensation are implemented considering the input limits of the actuators. The chatter in a specific milling condition is controlled and its maximum chatter-free axial depth is increased significantly.