Highly efficient piezoelectric actuators for active vibration control

An high performance/inexpensive diskbender actuator was produced by combining efficient design and fabrication methods and a new technique to operate these actuators was developed and tested, which can enhance the displacement and force capabilities by almost a factor of 2 by using the same maximal driving voltage. The properties of these actuators are intermediate between those of standard bimorphs, used for very large displacements but providing rather small forces, and those of low voltage stack multilayers, which provide quite large forces but are generally heavier, larger and expensive for equivalent displacements. The absence of any external mechanical amplification mechanism and their geometry make these actuators particularly suitable for active vibration damping applications within buildings affected by perturbations of hundreds of mum or for noise control by emission of controlled sound in antiphase. The class of displacement/force, which can be obtained with suitably dimensioned actuators, provides sufficient high motion even for the lower audio frequency region (400-1500 Hz). In order to lower the driving voltages, multilayer diskbenders were also fabricated with the same technique. The number of layers does not influence the actuator displacement and force properties but the increased capacity of the actuator may require sophisticated driving amplifiers.