Adaptive Neural-Network-Based Active Control of Regenerative Chatter in Micromilling

In this paper, an active control approach using two piezoelectric actuators (PZTAs) and an adaptive controller is investigated for suppressing the two-DOF regenerative chatter in micromilling. The PZTAs are utilized as active control elements to provide force compensation for chatter suppression. First, the dynamical model of micromilling process is demonstrated. Then, an adaptive controller is developed by employing neural networks to approximate the unknown dynamics of the cutting system and the unknown bounding functions related to the time-delayed tool vibrations, and applying the Lyapunov-Krasovskii functional to aid in treating the time-delayed effect of the regenerative mechanism of chatter. By employing the developed control approach, the tool vibrations in two directions vertical to each other are successfully suppressed. Finally, simulations are presented to validate the effectiveness of the developed control approach.