ACTIVE VIBRATION CONTROL FOR CHATTER SUPPRESSION

The vibration absorber, in its various forms, is a well-known control strategy that reduces the forced vibratory response of structures by introducing a carefully tuned, auxiliary degree of freedom. The method is simple, effective, and widely used. Recently, investigations have focused on the use of socalled active vibration absorbers for the suppression of machine-tool chatter. These absorbers are distinguished from their passive counterparts by the incorporation of various sensors and actuators to facilitate feedback control and thereby enhance the combined system response. In this paper, we consider a device, which we call an electronic vibration absorber; it is so-called because the auxiliary degree of freedom is simply a compensator realized via an electronicanalog circuit. In this regard, the technique is similar to the positive-position-feedback control algorithm and other popular second-order-compensation schemes in the literature. First, we develop the general theory for this device. Then, we consider its application to the problem of machine-tool chatter. The plant we consider in this study is a nonlinear single-degree-offreedom, machine-tool-chatter model that is known to possess a jump-type instability. A linear analysis is performed to determine the stability lobes of the controlled system. This analysis reveals that an electronic vibration absorber can increase the limit width of cut predicted in the modelling by approximately an order of magnitude. Furthermore, analogcomputer simulation of the complete nonlinear system predicts that the jump-type instability is eliminated by application of the absorber. We present a biaxial, electronic-vibration-absorber control system