Adaptive Control in Machining—A New Approach Based on the Physical Constraints of Tool Wear Mechanisms

An optimization procedure for adaptive control based on the physical constraints of the machining process is proposed. Three different modes of tool failure have been examined and constraints for each mode of failure identified accordingly. A mapping procedure has then been used to transform these constraints into a control variable space and obtain a “safe working range.” The optimum working conditions are determined in terms of the control variables (cutting speed and feed rate) based on a chosen performance index (metal removal rate, in this case). Also, further consideration of time-varying situations such as tool wear and engage-exit conditions can be included in this formulation. Several numerical examples are presented for the identification of the dominant modes of failure, in particular, experimental cases. The results are in good agreement with the experimental data available.