Sliding Mode Control of Machining Chatter in the Presence of Tool Wear and Parametric Uncertainties

Chatter suppression is essential for achieving high precision and surface quality in machining processes. In this paper, a control strategy is presented for chatter suppression in cutting process in the presence of tool wear and parameter uncertainties. A single-degree-of-freedom model of a turning process in the orthogonal cutting configuration is used to set up the nonlinear delay differential equation of motion that includes the effects of tool flank wear. Uncertainties in cutting velocity, tool wear size and parameters of the dynamic model are included in the model of the cutting process. The force provided by a piezo-actuator is taken as the control input of the system. A sliding mode control scheme is used and an effective control law is derived that suppresses chatter. Results of stability analysis and sliding mode control for two distinct cases of sharp and worn tools are presented and compared, which show the effectiveness of the approach.