Sensor-less chatter vibration monitoring by mechanical power factor

Avoidance of chatter vibration is the key technique for the automatic machining. Model-based chatter prediction methods and sensor-based on-line detection methods have been studied actively. In this study, the sensor-less chatter detection technique by power factor was proposed, which only used servo information. Though the power factor is originally introduced for representing electrical efficiency, we applied it to machining operation in mechanical system. Since mechanical power factor was calculated with both velocity and dynamic machining force estimated by disturbance observer, sensor-less chatter detection was theoretically feasible. Several turning tests were conducted to evaluate the performance of the proposed method.