Model predictive control based active chatter control in milling process

In high-speed milling process, chatter is often encountered due to the self-excitation mechanism, which not only limits the productivity, but also results in inferior work piece quality, shorter tool life, cutting noise and so on. In order to control chatter, an active chatter control method based on model predictive control is proposed in this work. Firstly, an active control structure is designed by integrating the specific tool holder, piezoelectric actuators and sensors into the spindle. Then, a time-varying model integrating the chatter dynamics is developed comprehensively considering the designed structure and the milling process. The model is then transformed into a linear time invariant (LTI) approximate model through zero order approximation (ZOA) and Padé approximation. Next, on the base of the model, a model predictive controller is designed to control only the chatter dynamics caused by regenerative effect. Finally, both simulation analysis and milling experiments are carried out to verify the effectiveness of the active chatter control method. The results show that the chatter is effectively controlled in the milling process and the milling stability is improved using the proposed active control method.