In the recent decade, active dampers have been introduced to machining for the avoidance of machine tool chatter in milling processes. The tuning strategy for most of these devices is based on models which do not account for the dynamics of control loop within the active dampers, hence neglect the dynamics of actuator and measuring device, and do not consider filtering. However, these simplified models might lead to inaccurate stability predictions which can deteriorate the performance of active dampers. In order to better approximate the real behavior of milling processes controlled by active dampers, this paper develops a new mathematical model which incorporates the dynamics of control loop within these devices. In particular, the inertial actuator is modeled as an electromagnetic proof-mass transducer, while the dynamics of piezoelectric accelerometer and finite-impulse-response filtering are also taken into account. By the computation of stability lobe diagrams, it is shown that, at low-frequency actuation and at high-speed milling, the consideration of control loop dynamics in active dampers can be essential.

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