Design of the Controller for Elimination of Self-excited Oscillations

The article deals with design of the controller for elimination of self-excited oscillations during machining. These oscillations are generated between a cutting tool and a work-piece surface and lead to decreased quality of the machined surface as well as decreased geometrical precision. The secondary effect is increased level of noise emissions. In general, the self-excited oscillations negatively affect the working productivity of metal cutting machines and inhibit its growth. The design of the controller is based on a model of the cutting process which works with so-called regenerative principle of the self-excited oscillations generation and is based on the variable chip thickness. The model itself serves to derivation of the controller gains. A piezoelectric compensator of the cutting force is controlled by the designed PSD controller. The compensator changes the position of the tool against the machined surface thereby changing the chip thickness.