All-Pass Filters in the Systems of Active Vibration Control of Weakly-Damped Systems

The problem of active vibration control of weakly damped mechanical structures is potentially unstable modes of vibrations due to the positive feedback for some vibration modes. The paper will discuss the change of positive feedback on the negative one using all-pass discrete-time filters. These filters can be arranged in a cascade to stabilize many potentially unstable modes. The piezoelectric actuator as a source of force is used to damp vibration.