Active and passive damping based on piezoelectric elements -controllability issues-

Piezoelectric elements are widely used for damping micro-vibrations in mechanical structures. Active damping can be realised robustly by means of collocated actuator-sensor-pairs, controlled so as to extract vibration energy. Excellent damping performance is possible as long as sufficient controllability is assured. Passive damping based on a single piezoelectric element can be realised by the use of a resistive shunt. Damping performance however is very poor, due to the lack of controllability. A single piezoelectric element can also be used actively, in a self-sensing configuration, so as to improve controllability and damping performance. The non-linear capacitance of a piezoelectric element however endangers the robustness of the control scheme