Development of chatter vibration detection utilizing disturbance observer (1st report) precise sensor-less process monitoring utilizing average T method

This paper presents a sensor-less process monitoring method to detect chatter vibration in square end milling. The method of monitoring cutting forces and detecting chatter vibration using external sensors such as accelerometer and force sensor has been proposed. However, using external sensors increases the cost of manufacturing systems and additional structures for sensor implementation often decrease the stiffness of workpiece fixturing, and it results in another chatter vibration. Therefore, a novel method without using any external sensors is developed to detect high-frequency vibration. Concretely, disturbance torque acting on the spindle is estimated by using disturbance observer and used simultaneously for spectrum analysis. From the experimental results, it is confirmed that the proposed method enables to estimate high-frequency disturbance. Certain peaks which are considered as a peak frequency of chatter vibration can be detected.