Feed drive control tuning considering machine dynamics and chatter stability

In large machine tools, where structural dynamics significantly influences the cutting stability, judicious selection of the servo control parameters can increase the damping, thereby improving the chatter stability. This paper presents a new strategy for feed drive controller tuning, which takes this effect into consideration. The proposed strategy generalizes successfully to machine tool structures with high order dynamics, and integrates model-free frequency domain estimation and analysis techniques with model-based root locus design, the latter which is achieved through an efficient and accurate identification approach. The proposed strategy has been tested in machining stability tests, demonstrating up to 30% increase in productivity.