Robust control of regenerative chatter in uncertain milling process with weak nonlinear cutting forces: A comparison with linear model

Abstract

Abstract For various types of materials, milling process is extensively used to generate complex shapes with high quality. During the process and to achieve high removal rate, precision and better surface finish, chatter suppression is of great importance. An extended model of the milling process is presented in which the cutting forces are described as a third-order nonlinear function of chip thickness. Uncertainties associated with the process and tool parameters are also included to achieve a more realistic model. To suppress regenerative chatter, an H∞ robust control is designed based on µ-synthesis with DK-iteration algorithm. The controller guarantees the robust stability and performance of both linear and nonlinear models in the presence of uncertainties. In both models, as the amount of uncertainty increases, more actuator efforts are required to suppress the chatter. The linear model needs less actuation and time to suppress the chatter. However, as the nonlinear effects are increased, the controller must be re-designed.